[v3,4/6] mtd: rawnand: add NVIDIA Tegra NAND Flash controller driver

Add support for the NAND flash controller found on NVIDIA
Tegra 2 SoCs. This implementation does not make use of the
command queue feature. Regular operations/data transfers are
done in PIO mode. Page read/writes with hardware ECC make
use of the DMA for data transfer.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 MAINTAINERS                       |    7 +
 drivers/mtd/nand/raw/Kconfig      |    6 +
 drivers/mtd/nand/raw/Makefile     |    1 +
 drivers/mtd/nand/raw/tegra_nand.c | 1143 +++++++++++++++++++++++++++++
 4 files changed, 1157 insertions(+)
 create mode 100644 drivers/mtd/nand/raw/tegra_nand.c

On 01.06.2018 01:16, Stefan Agner wrote:
> Add support for the NAND flash controller found on NVIDIA
> Tegra 2 SoCs. This implementation does not make use of the
> command queue feature. Regular operations/data transfers are
> done in PIO mode. Page read/writes with hardware ECC make
> use of the DMA for data transfer.
> 
> Signed-off-by: Lucas Stach <dev@lynxeye.de>
> Signed-off-by: Stefan Agner <stefan@agner.ch>
> ---
>  MAINTAINERS                       |    7 +
>  drivers/mtd/nand/raw/Kconfig      |    6 +
>  drivers/mtd/nand/raw/Makefile     |    1 +
>  drivers/mtd/nand/raw/tegra_nand.c | 1143 +++++++++++++++++++++++++++++
>  4 files changed, 1157 insertions(+)
>  create mode 100644 drivers/mtd/nand/raw/tegra_nand.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 58b9861ccf99..c2e5571c85d4 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -13844,6 +13844,13 @@ M:	Laxman Dewangan <ldewangan@nvidia.com>
>  S:	Supported
>  F:	drivers/input/keyboard/tegra-kbc.c
>  
> +TEGRA NAND DRIVER
> +M:	Stefan Agner <stefan@agner.ch>
> +M:	Lucas Stach <dev@lynxeye.de>
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/mtd/nvidia-tegra20-nand.txt
> +F:	drivers/mtd/nand/raw/tegra_nand.c
> +
>  TEGRA PWM DRIVER
>  M:	Thierry Reding <thierry.reding@gmail.com>
>  S:	Supported
> diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
> index 19a2b283fbbe..e9093f52371e 100644
> --- a/drivers/mtd/nand/raw/Kconfig
> +++ b/drivers/mtd/nand/raw/Kconfig
> @@ -534,4 +534,10 @@ config MTD_NAND_MTK
>  	  Enables support for NAND controller on MTK SoCs.
>  	  This controller is found on mt27xx, mt81xx, mt65xx SoCs.
>  
> +config MTD_NAND_TEGRA
> +	tristate "Support for NAND controller on NVIDIA Tegra"
> +	depends on ARCH_TEGRA || COMPILE_TEST
> +	help
> +	  Enables support for NAND flash controller on NVIDIA Tegra SoC.
> +
>  endif # MTD_NAND
> diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile
> index 165b7ef9e9a1..d5a5f9832b88 100644
> --- a/drivers/mtd/nand/raw/Makefile
> +++ b/drivers/mtd/nand/raw/Makefile
> @@ -56,6 +56,7 @@ obj-$(CONFIG_MTD_NAND_HISI504)	        += hisi504_nand.o
>  obj-$(CONFIG_MTD_NAND_BRCMNAND)		+= brcmnand/
>  obj-$(CONFIG_MTD_NAND_QCOM)		+= qcom_nandc.o
>  obj-$(CONFIG_MTD_NAND_MTK)		+= mtk_ecc.o mtk_nand.o
> +obj-$(CONFIG_MTD_NAND_TEGRA)		+= tegra_nand.o
>  
>  nand-objs := nand_base.o nand_bbt.o nand_timings.o nand_ids.o
>  nand-objs += nand_amd.o
> diff --git a/drivers/mtd/nand/raw/tegra_nand.c b/drivers/mtd/nand/raw/tegra_nand.c
> new file mode 100644
> index 000000000000..e9664f2938a3
> --- /dev/null
> +++ b/drivers/mtd/nand/raw/tegra_nand.c
> @@ -0,0 +1,1143 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2018 Stefan Agner <stefan@agner.ch>
> + * Copyright (C) 2014-2015 Lucas Stach <dev@lynxeye.de>
> + * Copyright (C) 2012 Avionic Design GmbH
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/completion.h>
> +#include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/err.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/mtd/partitions.h>
> +#include <linux/mtd/rawnand.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +
> +#define CMD					0x00
> +#define   CMD_GO				BIT(31)
> +#define   CMD_CLE				BIT(30)
> +#define   CMD_ALE				BIT(29)
> +#define   CMD_PIO				BIT(28)
> +#define   CMD_TX				BIT(27)
> +#define   CMD_RX				BIT(26)
> +#define   CMD_SEC_CMD				BIT(25)
> +#define   CMD_AFT_DAT				BIT(24)
> +#define   CMD_TRANS_SIZE(x)			(((x - 1) & 0xf) << 20)
> +#define   CMD_A_VALID				BIT(19)
> +#define   CMD_B_VALID				BIT(18)
> +#define   CMD_RD_STATUS_CHK			BIT(17)
> +#define   CMD_RBSY_CHK				BIT(16)
> +#define   CMD_CE(x)				BIT((8 + ((x) & 0x7)))
> +#define   CMD_CLE_SIZE(x)			(((x - 1) & 0x3) << 4)
> +#define   CMD_ALE_SIZE(x)			(((x - 1) & 0xf) << 0)
> +
> +#define STATUS					0x04
> +
> +#define ISR					0x08
> +#define   ISR_CORRFAIL_ERR			BIT(24)
> +#define   ISR_UND				BIT(7)
> +#define   ISR_OVR				BIT(6)
> +#define   ISR_CMD_DONE				BIT(5)
> +#define   ISR_ECC_ERR				BIT(4)
> +
> +#define IER					0x0c
> +#define   IER_ERR_TRIG_VAL(x)			(((x) & 0xf) << 16)
> +#define   IER_UND				BIT(7)
> +#define   IER_OVR				BIT(6)
> +#define   IER_CMD_DONE				BIT(5)
> +#define   IER_ECC_ERR				BIT(4)
> +#define   IER_GIE				BIT(0)
> +
> +#define CFG					0x10
> +#define   CFG_HW_ECC				BIT(31)
> +#define   CFG_ECC_SEL				BIT(30)
> +#define   CFG_ERR_COR				BIT(29)
> +#define   CFG_PIPE_EN				BIT(28)
> +#define   CFG_TVAL_4				(0 << 24)
> +#define   CFG_TVAL_6				(1 << 24)
> +#define   CFG_TVAL_8				(2 << 24)
> +#define   CFG_SKIP_SPARE			BIT(23)
> +#define   CFG_BUS_WIDTH_16			BIT(21)
> +#define   CFG_COM_BSY				BIT(20)
> +#define   CFG_PS_256				(0 << 16)
> +#define   CFG_PS_512				(1 << 16)
> +#define   CFG_PS_1024				(2 << 16)
> +#define   CFG_PS_2048				(3 << 16)
> +#define   CFG_PS_4096				(4 << 16)
> +#define   CFG_SKIP_SPARE_SIZE_4			(0 << 14)
> +#define   CFG_SKIP_SPARE_SIZE_8			(1 << 14)
> +#define   CFG_SKIP_SPARE_SIZE_12		(2 << 14)
> +#define   CFG_SKIP_SPARE_SIZE_16		(3 << 14)
> +#define   CFG_TAG_BYTE_SIZE(x)			((x) & 0xff)
> +
> +#define TIMING_1				0x14
> +#define   TIMING_TRP_RESP(x)			(((x) & 0xf) << 28)
> +#define   TIMING_TWB(x)				(((x) & 0xf) << 24)
> +#define   TIMING_TCR_TAR_TRR(x)			(((x) & 0xf) << 20)
> +#define   TIMING_TWHR(x)			(((x) & 0xf) << 16)
> +#define   TIMING_TCS(x)				(((x) & 0x3) << 14)
> +#define   TIMING_TWH(x)				(((x) & 0x3) << 12)
> +#define   TIMING_TWP(x)				(((x) & 0xf) <<  8)
> +#define   TIMING_TRH(x)				(((x) & 0x3) <<  4)
> +#define   TIMING_TRP(x)				(((x) & 0xf) <<  0)
> +
> +#define RESP					0x18
> +
> +#define TIMING_2				0x1c
> +#define   TIMING_TADL(x)			((x) & 0xf)
> +
> +#define CMD_1					0x20
> +#define CMD_2					0x24
> +#define ADDR_1					0x28
> +#define ADDR_2					0x2c
> +
> +#define DMA_CTRL				0x30
> +#define   DMA_CTRL_GO				BIT(31)
> +#define   DMA_CTRL_IN				(0 << 30)
> +#define   DMA_CTRL_OUT				BIT(30)
> +#define   DMA_CTRL_PERF_EN			BIT(29)
> +#define   DMA_CTRL_IE_DONE			BIT(28)
> +#define   DMA_CTRL_REUSE			BIT(27)
> +#define   DMA_CTRL_BURST_1			(2 << 24)
> +#define   DMA_CTRL_BURST_4			(3 << 24)
> +#define   DMA_CTRL_BURST_8			(4 << 24)
> +#define   DMA_CTRL_BURST_16			(5 << 24)
> +#define   DMA_CTRL_IS_DONE			BIT(20)
> +#define   DMA_CTRL_EN_A				BIT(2)
> +#define   DMA_CTRL_EN_B				BIT(1)
> +
> +#define DMA_CFG_A				0x34
> +#define DMA_CFG_B				0x38
> +
> +#define FIFO_CTRL				0x3c
> +#define   FIFO_CTRL_CLR_ALL			BIT(3)
> +
> +#define DATA_PTR				0x40
> +#define TAG_PTR					0x44
> +#define ECC_PTR					0x48
> +
> +#define DEC_STATUS				0x4c
> +#define   DEC_STATUS_A_ECC_FAIL			BIT(1)
> +#define   DEC_STATUS_ERR_COUNT_MASK		0x00ff0000
> +#define   DEC_STATUS_ERR_COUNT_SHIFT		16
> +
> +#define HWSTATUS_CMD				0x50
> +#define HWSTATUS_MASK				0x54
> +#define   HWSTATUS_RDSTATUS_MASK(x)		(((x) & 0xff) << 24)
> +#define   HWSTATUS_RDSTATUS_VALUE(x)		(((x) & 0xff) << 16)
> +#define   HWSTATUS_RBSY_MASK(x)			(((x) & 0xff) << 8)
> +#define   HWSTATUS_RBSY_VALUE(x)		(((x) & 0xff) << 0)
> +
> +#define BCH_CONFIG				0xcc
> +#define   BCH_ENABLE				BIT(0)
> +#define   BCH_TVAL_4				(0 << 4)
> +#define   BCH_TVAL_8				(1 << 4)
> +#define   BCH_TVAL_14				(2 << 4)
> +#define   BCH_TVAL_16				(3 << 4)
> +
> +#define DEC_STAT_RESULT				0xd0
> +#define DEC_STAT_BUF				0xd4
> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_MASK	0xff000000
> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_SHIFT	24
> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_MASK	0x00ff0000
> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT	16
> +#define   DEC_STAT_BUF_MAX_CORR_CNT_MASK	0x00001f00
> +#define   DEC_STAT_BUF_MAX_CORR_CNT_SHIFT	8
> +
> +#define OFFSET(val, off)		((val) < (off) ? 0 : (val) - (off))
> +
> +#define SKIP_SPARE_BYTES	4
> +#define BITS_PER_STEP_RS	18
> +#define BITS_PER_STEP_BCH	13
> +
> +struct tegra_nand_controller {
> +	struct nand_hw_control controller;
> +	void __iomem *regs;
> +	struct clk *clk;
> +	struct device *dev;
> +	struct completion command_complete;
> +	struct completion dma_complete;
> +	bool last_read_error;
> +	int cur_chip;
> +	struct nand_chip *chip;
> +};
> +
> +struct tegra_nand_chip {
> +	struct nand_chip chip;
> +	struct gpio_desc *wp_gpio;
> +	struct mtd_oob_region tag;
> +};
> +
> +static inline struct tegra_nand_controller *to_tegra_ctrl(
> +						struct nand_hw_control *hw_ctrl)
> +{
> +	return container_of(hw_ctrl, struct tegra_nand_controller, controller);
> +}
> +
> +static inline struct tegra_nand_chip *to_tegra_chip(struct nand_chip *chip)
> +{
> +	return container_of(chip, struct tegra_nand_chip, chip);
> +}
> +
> +static int tegra_nand_ooblayout_rs_ecc(struct mtd_info *mtd, int section,
> +				       struct mtd_oob_region *oobregion)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS * chip->ecc.strength,
> +					  BITS_PER_BYTE);
> +
> +	if (section > 0)
> +		return -ERANGE;
> +
> +	oobregion->offset = SKIP_SPARE_BYTES;
> +	oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 4);
> +
> +	return 0;
> +}
> +
> +static int tegra_nand_ooblayout_rs_free(struct mtd_info *mtd, int section,
> +					struct mtd_oob_region *oobregion)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS * chip->ecc.strength,
> +					  BITS_PER_BYTE);
> +
> +	if (section > 0)
> +		return -ERANGE;
> +
> +	oobregion->offset = SKIP_SPARE_BYTES +
> +			    round_up(bytes_per_step * chip->ecc.steps, 4);
> +	oobregion->length = mtd->oobsize - oobregion->offset;
> +
> +	return 0;
> +}
> +
> +static const struct mtd_ooblayout_ops tegra_nand_oob_rs_ops = {
> +	.ecc = tegra_nand_ooblayout_rs_ecc,
> +	.free = tegra_nand_ooblayout_rs_free,
> +};
> +
> +static int tegra_nand_ooblayout_bch_ecc(struct mtd_info *mtd, int section,
> +				       struct mtd_oob_region *oobregion)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH * chip->ecc.strength,
> +					  BITS_PER_BYTE);
> +
> +	if (section > 0)
> +		return -ERANGE;
> +
> +	oobregion->offset = SKIP_SPARE_BYTES;
> +	oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 4);
> +
> +	return 0;
> +}
> +
> +static int tegra_nand_ooblayout_bch_free(struct mtd_info *mtd, int section,
> +					struct mtd_oob_region *oobregion)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH * chip->ecc.strength,
> +					  BITS_PER_BYTE);
> +
> +	if (section > 0)
> +		return -ERANGE;
> +
> +	oobregion->offset = SKIP_SPARE_BYTES +
> +			    round_up(bytes_per_step * chip->ecc.steps, 4);
> +	oobregion->length = mtd->oobsize - oobregion->offset;
> +
> +	return 0;
> +}
> +
> +/*
> + * Layout with tag bytes is
> + *
> + * --------------------------------------------------------------------------
> + * | main area                       | skip bytes | tag bytes | parity | .. |
> + * --------------------------------------------------------------------------
> + *
> + * If not tag bytes are written, parity moves right after skip bytes!
> + */
> +static const struct mtd_ooblayout_ops tegra_nand_oob_bch_ops = {
> +	.ecc = tegra_nand_ooblayout_bch_ecc,
> +	.free = tegra_nand_ooblayout_bch_free,
> +};
> +
> +static irqreturn_t tegra_nand_irq(int irq, void *data)
> +{
> +	struct tegra_nand_controller *ctrl = data;
> +	u32 isr, dma;
> +
> +	isr = readl_relaxed(ctrl->regs + ISR);
> +	dma = readl_relaxed(ctrl->regs + DMA_CTRL);
> +	dev_dbg(ctrl->dev, "isr %08x\n", isr);
> +
> +	if (!isr && !(dma & DMA_CTRL_IS_DONE))
> +		return IRQ_NONE;
> +
> +	/*
> +	 * The bit name is somewhat missleading: This is also set when
> +	 * HW ECC was successful. The data sheet states:
> +	 * Correctable OR Un-correctable errors occurred in the DMA transfer...
> +	 */
> +	if (isr & ISR_CORRFAIL_ERR)
> +		ctrl->last_read_error = true;
> +
> +	if (isr & ISR_CMD_DONE)
> +		complete(&ctrl->command_complete);
> +
> +	if (isr & ISR_UND)
> +		dev_err(ctrl->dev, "FIFO underrun\n");
> +
> +	if (isr & ISR_OVR)
> +		dev_err(ctrl->dev, "FIFO overrun\n");
> +
> +	/* handle DMA interrupts */
> +	if (dma & DMA_CTRL_IS_DONE) {
> +		writel_relaxed(dma, ctrl->regs + DMA_CTRL);
> +		complete(&ctrl->dma_complete);
> +	}
> +
> +	/* clear interrupts */
> +	writel_relaxed(isr, ctrl->regs + ISR);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static const char * const tegra_nand_reg_names[] = {
> +	"COMMAND",
> +	"STATUS",
> +	"ISR",
> +	"IER",
> +	"CONFIG",
> +	"TIMING",
> +	NULL,
> +	"TIMING2",
> +	"CMD_REG1",
> +	"CMD_REG2",
> +	"ADDR_REG1",
> +	"ADDR_REG2",
> +	"DMA_MST_CTRL",
> +	"DMA_CFG_A",
> +	"DMA_CFG_B",
> +	"FIFO_CTRL",
> +};
> +
> +static void tegra_nand_dump_reg(struct tegra_nand_controller *ctrl)
> +{
> +	u32 reg;
> +	int i;
> +
> +	dev_err(ctrl->dev, "Tegra NAND controller register dump\n");
> +	for (i = 0; i < ARRAY_SIZE(tegra_nand_reg_names); i++) {
> +		const char *reg_name = tegra_nand_reg_names[i];
> +
> +		if (!reg_name)
> +			continue;
> +
> +		reg = readl_relaxed(ctrl->regs + (i * 4));
> +		dev_err(ctrl->dev, "%s: 0x%08x\n", reg_name, reg);
> +	}
> +}
> +
> +static int tegra_nand_cmd(struct nand_chip *chip,
> +			 const struct nand_subop *subop)
> +{
> +	const struct nand_op_instr *instr;
> +	const struct nand_op_instr *instr_data_in = NULL;
> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
> +	unsigned int op_id, size = 0, offset = 0;
> +	bool first_cmd = true;
> +	u32 reg, cmd = 0;
> +	int ret;
> +
> +	for (op_id = 0; op_id < subop->ninstrs; op_id++) {
> +		unsigned int naddrs, i;
> +		const u8 *addrs;
> +		u32 addr1 = 0, addr2 = 0;
> +
> +		instr = &subop->instrs[op_id];
> +
> +		switch (instr->type) {
> +		case NAND_OP_CMD_INSTR:
> +			if (first_cmd) {
> +				cmd |= CMD_CLE;
> +				writel_relaxed(instr->ctx.cmd.opcode,
> +					       ctrl->regs + CMD_1);
> +			} else {
> +				cmd |= CMD_SEC_CMD;
> +				writel_relaxed(instr->ctx.cmd.opcode,
> +					       ctrl->regs + CMD_2);
> +			}
> +			first_cmd = false;
> +			break;
> +		case NAND_OP_ADDR_INSTR:
> +			offset = nand_subop_get_addr_start_off(subop, op_id);
> +			naddrs = nand_subop_get_num_addr_cyc(subop, op_id);
> +			addrs = &instr->ctx.addr.addrs[offset];
> +
> +			cmd |= CMD_ALE | CMD_ALE_SIZE(naddrs);
> +			for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
> +				addr1 |= *addrs++ << (BITS_PER_BYTE * i);
> +			naddrs -= i;
> +			for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
> +				addr2 |= *addrs++ << (BITS_PER_BYTE * i);
> +			writel_relaxed(addr1, ctrl->regs + ADDR_1);
> +			writel_relaxed(addr2, ctrl->regs + ADDR_2);
> +			break;
> +
> +		case NAND_OP_DATA_IN_INSTR:
> +			size = nand_subop_get_data_len(subop, op_id);
> +			offset = nand_subop_get_data_start_off(subop, op_id);
> +
> +			cmd |= CMD_TRANS_SIZE(size) | CMD_PIO | CMD_RX |
> +				CMD_A_VALID;
> +
> +			instr_data_in = instr;
> +			break;
> +
> +		case NAND_OP_DATA_OUT_INSTR:
> +			size = nand_subop_get_data_len(subop, op_id);
> +			offset = nand_subop_get_data_start_off(subop, op_id);
> +
> +			cmd |= CMD_TRANS_SIZE(size) | CMD_PIO | CMD_TX |
> +				CMD_A_VALID;
> +
> +			memcpy(&reg, instr->ctx.data.buf.out + offset, size);
> +			writel_relaxed(reg, ctrl->regs + RESP);
> +
> +			break;
> +		case NAND_OP_WAITRDY_INSTR:
> +			cmd |= CMD_RBSY_CHK;
> +			break;
> +
> +		}
> +	}
> +
> +	cmd |= CMD_GO | CMD_CE(ctrl->cur_chip);
> +	writel_relaxed(cmd, ctrl->regs + CMD);
> +	ret = wait_for_completion_timeout(&ctrl->command_complete,
> +					  msecs_to_jiffies(500));
> +	if (!ret) {
> +		dev_err(ctrl->dev, "CMD timeout\n");
> +		tegra_nand_dump_reg(ctrl);
> +		return -ETIMEDOUT;
> +	}

- wait_for_completion_timeout() could fail
- HW shall be reset
- completion shall be re-inited because IRQ could fire just after the completion
timeout

I'd write it something like this:

#define INT_MASK	(IER_UND | IER_OVR | IER_CMD_DONE | IER_GIE)

#define HWSTATUS_MASK	(HWSTATUS_RDSTATUS_MASK(1) |		 \
			 HWSTATUS_RDSTATUS_VALUE(0) |		 \
			 HWSTATUS_RBSY_MASK(NAND_STATUS_READY) | \
			 HWSTATUS_RBSY_VALUE(NAND_STATUS_READY))

#define HW_TIMEOUT	500	

void tegra_nand_controller_reset(struct tegra_nand_controller *ctrl)
{
	int err;

	disable_irq(ctrl->irq);

	err = reset_control_reset(ctrl->rst);
	if (err) {
		dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
		msleep(HW_TIMEOUT);
	}

	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
	writel_relaxed(HWSTATUS_MASK, ctrl->regs + HWSTATUS_MASK);
	writel_relaxed(INT_MASK, ctrl->regs + ISR);

	reinit_completion(&ctrl->command_complete);
	reinit_completion(&ctrl->dma_complete);

	enable_irq(ctrl->irq);
}

...

	ret = wait_for_completion_timeout(&ctrl->command_complete,
					  msecs_to_jiffies(HW_TIMEOUT));
	if (ret <= 0) {
		if (ret == 0) {
			dev_err(ctrl->dev, "CMD timeout\n");
			tegra_nand_dump_reg(ctrl);
			ret = -ETIMEDOUT;
		} else {
			dev_err(ctrl->dev,
				"Failed to wait for CMD completion: %d\n",
				ret);
		}

		tegra_nand_controller_reset(ctrl);
		return ret;
	}

> +
> +	if (instr_data_in) {
> +		reg = readl_relaxed(ctrl->regs + RESP);
> +		memcpy(instr_data_in->ctx.data.buf.in + offset, &reg, size);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct nand_op_parser tegra_nand_op_parser = NAND_OP_PARSER(
> +	NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
> +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
> +		NAND_OP_PARSER_PAT_ADDR_ELEM(true, 8),
> +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
> +		NAND_OP_PARSER_PAT_WAITRDY_ELEM(true)),
> +	NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
> +		NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, 4)),
> +	NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
> +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
> +		NAND_OP_PARSER_PAT_ADDR_ELEM(true, 8),
> +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
> +		NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
> +		NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, 4)),
> +	);
> +
> +static int tegra_nand_exec_op(struct nand_chip *chip,
> +			     const struct nand_operation *op,
> +			     bool check_only)
> +{
> +	return nand_op_parser_exec_op(chip, &tegra_nand_op_parser, op,
> +				      check_only);
> +}
> +static void tegra_nand_select_chip(struct mtd_info *mtd, int chip_nr)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
> +
> +	ctrl->cur_chip = chip_nr;
> +}
> +
> +static void tegra_nand_hw_ecc(struct tegra_nand_controller *ctrl,
> +			      struct nand_chip *chip, bool enable)
> +{
> +	u32 reg;
> +
> +	switch (chip->ecc.algo) {
> +	case NAND_ECC_RS:
> +		reg = readl_relaxed(ctrl->regs + CFG);
> +		if (enable)
> +			reg |= CFG_HW_ECC | CFG_ERR_COR;
> +		else
> +			reg &= ~(CFG_HW_ECC | CFG_ERR_COR);
> +		writel_relaxed(reg, ctrl->regs + CFG);
> +		break;
> +	case NAND_ECC_BCH:
> +		reg = readl_relaxed(ctrl->regs + BCH_CONFIG);
> +		if (enable)
> +			reg |= BCH_ENABLE;
> +		else
> +			reg &= ~BCH_ENABLE;
> +		writel_relaxed(reg, ctrl->regs + BCH_CONFIG);
> +		break;
> +	default:
> +		dev_err(ctrl->dev, "Unsupported hardware ECC algorithm\n");
> +		break;
> +	}
> +}
> +
> +static int tegra_nand_page_xfer(struct mtd_info *mtd, struct nand_chip *chip,
> +				void *buf, int oob_required, int page,
> +				bool read)
> +{
> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
> +	struct tegra_nand_chip *nand = to_tegra_chip(chip);
> +	enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
> +	dma_addr_t dma_addr;
> +	u32 cmd, dma_ctrl;
> +	int ret, dma_len;
> +
> +	if (read) {
> +		writel_relaxed(NAND_CMD_READ0, ctrl->regs + CMD_1);
> +		writel_relaxed(NAND_CMD_READSTART, ctrl->regs + CMD_2);
> +	} else {
> +		writel_relaxed(NAND_CMD_SEQIN, ctrl->regs + CMD_1);
> +		writel_relaxed(NAND_CMD_PAGEPROG, ctrl->regs + CMD_2);
> +	}
> +	cmd = CMD_CLE | CMD_SEC_CMD;
> +
> +	/* Lower 16-bits are column, always 0 */
> +	writel_relaxed(page << 16, ctrl->regs + ADDR_1);
> +
> +	if (chip->options & NAND_ROW_ADDR_3) {
> +		writel_relaxed(page >> 16, ctrl->regs + ADDR_2);
> +		cmd |= CMD_ALE | CMD_ALE_SIZE(5);
> +	} else {
> +		cmd |= CMD_ALE | CMD_ALE_SIZE(4);
> +	}
> +
> +	dma_len = mtd->writesize + (oob_required ? mtd->oobsize : 0);
> +	dma_addr = dma_map_single(ctrl->dev, buf, dma_len, dir);
> +	ret = dma_mapping_error(ctrl->dev, dma_addr);
> +	if (ret) {
> +		dev_err(ctrl->dev, "dma mapping error\n");
> +		return -EINVAL;
> +	}
> +
> +	writel_relaxed(mtd->writesize - 1, ctrl->regs + DMA_CFG_A);
> +	writel_relaxed(dma_addr, ctrl->regs + DATA_PTR);
> +
> +	if (oob_required) {
> +		dma_addr_t dma_addr_tag = dma_addr + mtd->writesize;
> +
> +		writel_relaxed(nand->tag.length - 1, ctrl->regs + DMA_CFG_B);
> +		writel_relaxed(dma_addr_tag + nand->tag.offset,
> +			       ctrl->regs + TAG_PTR);
> +	} else {
> +		writel_relaxed(0, ctrl->regs + DMA_CFG_B);
> +		writel_relaxed(0, ctrl->regs + TAG_PTR);
> +	}
> +
> +	dma_ctrl = DMA_CTRL_GO | DMA_CTRL_PERF_EN |
> +		   DMA_CTRL_IE_DONE | DMA_CTRL_IS_DONE |
> +		   DMA_CTRL_BURST_16 | DMA_CTRL_EN_A;
> +	if (oob_required)
> +		dma_ctrl |= DMA_CTRL_EN_B;
> +	if (read)
> +		dma_ctrl |= DMA_CTRL_IN | DMA_CTRL_REUSE;
> +	else
> +		dma_ctrl |= DMA_CTRL_OUT;
> +
> +	writel_relaxed(dma_ctrl, ctrl->regs + DMA_CTRL);
> +
> +	cmd |= CMD_GO | CMD_RBSY_CHK | CMD_TRANS_SIZE(9) |
> +	       CMD_CE(ctrl->cur_chip) | CMD_A_VALID;
> +	if (oob_required)
> +		cmd |= CMD_B_VALID;
> +	if (read)
> +		cmd |= CMD_RX;
> +	else
> +		cmd |= CMD_TX | CMD_AFT_DAT;
> +
> +	writel_relaxed(cmd, ctrl->regs + CMD);
> +
> +	ret = wait_for_completion_timeout(&ctrl->command_complete,
> +					  msecs_to_jiffies(500));
> +	if (!ret) {
> +		dev_err(ctrl->dev, "CMD timeout\n");
> +		tegra_nand_dump_reg(ctrl);
> +		ret = -ETIMEDOUT;
> +		goto err_unmap_dma;
> +	}
> +
> +	ret = wait_for_completion_timeout(&ctrl->dma_complete,
> +					  msecs_to_jiffies(500));
> +	if (!ret) {
> +		dev_err(ctrl->dev, "DMA timeout\n");
> +		tegra_nand_dump_reg(ctrl);
> +		ret = -ETIMEDOUT;
> +		goto err_unmap_dma;
> +	}
> +	ret = 0;

Same as the above comment regarding the wait_for_completion_timeout().

> +
> +err_unmap_dma:
> +	dma_unmap_single(ctrl->dev, dma_addr, dma_len, dir);
> +
> +	return ret;
> +}
> +
> +static int tegra_nand_read_page_hwecc(struct mtd_info *mtd,
> +				      struct nand_chip *chip,
> +				      uint8_t *buf, int oob_required, int page)
> +{
> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
> +	u32 dec_stat, max_corr_cnt;
> +	unsigned long fail_sec_flag;
> +	int ret;
> +
> +	tegra_nand_hw_ecc(ctrl, chip, true);
> +	ret = tegra_nand_page_xfer(mtd, chip, buf, oob_required, page, true);
> +	tegra_nand_hw_ecc(ctrl, chip, false);
> +	if (ret)
> +		return ret;
> +
> +	/* No correctable or un-correctable errors, page must have 0 bitflips */
> +	if (!ctrl->last_read_error)
> +		return 0;
> +
> +	/*
> +	 * Correctable or un-correctable errors occurred. Use DEC_STAT_BUF
> +	 * which contains information for all ECC selections.
> +	 *
> +	 * Note that since we do not use Command Queues DEC_RESULT does not
> +	 * state the number of pages we can read from the DEC_STAT_BUF. But
> +	 * since CORRFAIL_ERR did occur during page read we do have a valid
> +	 * result in DEC_STAT_BUF.
> +	 */
> +	ctrl->last_read_error = false;
> +	dec_stat = readl_relaxed(ctrl->regs + DEC_STAT_BUF);
> +
> +	fail_sec_flag = (dec_stat & DEC_STAT_BUF_FAIL_SEC_FLAG_MASK) >>
> +			DEC_STAT_BUF_FAIL_SEC_FLAG_SHIFT;
> +
> +	max_corr_cnt = (dec_stat & DEC_STAT_BUF_MAX_CORR_CNT_MASK) >>
> +		       DEC_STAT_BUF_MAX_CORR_CNT_SHIFT;
> +
> +	if (fail_sec_flag) {
> +		int bit, max_bitflips = 0;
> +
> +		/*
> +		 * Check if all sectors in a page failed. If only some failed
> +		 * its definitly not an erased page and we can return error
> +		 * stats right away.
> +		 *
> +		 * E.g. controller might return fail_sec_flag with 0x4, which
> +		 * would mean only the third sector failed to correct.
> +		 */
> +		if (fail_sec_flag ^ GENMASK(chip->ecc.steps - 1, 0)) {
> +			mtd->ecc_stats.failed += hweight8(fail_sec_flag);
> +			return max_corr_cnt;
> +		}
> +
> +		/*
> +		 * All sectors failed to correct, but the ECC isn't smart
> +		 * enough to figure out if a page is really completely erased.
> +		 * We check the read data here to figure out if it's a
> +		 * legitimate ECC error or only an erased page.
> +		 */
> +		for_each_set_bit(bit, &fail_sec_flag, chip->ecc.steps) {
> +			u8 *data = buf + (chip->ecc.size * bit);
> +
> +			ret = nand_check_erased_ecc_chunk(data, chip->ecc.size,
> +							  NULL, 0,
> +							  NULL, 0,
> +							  chip->ecc.strength);
> +			if (ret < 0)
> +				mtd->ecc_stats.failed++;
> +			else
> +				max_bitflips = max(ret, max_bitflips);
> +		}
> +
> +		return max_t(unsigned int, max_corr_cnt, max_bitflips);
> +	} else {
> +		int corr_sec_flag;
> +
> +		corr_sec_flag = (dec_stat & DEC_STAT_BUF_CORR_SEC_FLAG_MASK) >>
> +				DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT;
> +
> +		/*
> +		 * The value returned in the register is the maximum of
> +		 * bitflips encountered in any of the ECC regions. As there is
> +		 * no way to get the number of bitflips in a specific regions
> +		 * we are not able to deliver correct stats but instead
> +		 * overestimate the number of corrected bitflips by assuming
> +		 * that all regions where errors have been corrected
> +		 * encountered the maximum number of bitflips.
> +		 */
> +		mtd->ecc_stats.corrected += max_corr_cnt * hweight8(corr_sec_flag);
> +
> +		return max_corr_cnt;
> +	}
> +
> +}
> +
> +static int tegra_nand_write_page_hwecc(struct mtd_info *mtd,
> +				       struct nand_chip *chip,
> +				       const uint8_t *buf, int oob_required,
> +				       int page)
> +{
> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
> +	int ret;
> +
> +	tegra_nand_hw_ecc(ctrl, chip, true);
> +	ret = tegra_nand_page_xfer(mtd, chip, (void *)buf, oob_required, page,
> +				   false);
> +	tegra_nand_hw_ecc(ctrl, chip, false);
> +
> +	return ret;
> +}
> +
> +static void tegra_nand_setup_timing(struct tegra_nand_controller *ctrl,
> +				    const struct nand_sdr_timings *timings)
> +{
> +	/*
> +	 * The period (and all other timings in this function) is in ps,
> +	 * so need to take care here to avoid integer overflows.
> +	 */
> +	unsigned int rate = clk_get_rate(ctrl->clk) / 1000000;
> +	unsigned int period = DIV_ROUND_UP(1000000, rate);
> +	u32 val, reg = 0;
> +
> +	val = DIV_ROUND_UP(max3(timings->tAR_min, timings->tRR_min,
> +				timings->tRC_min), period);
> +	reg |= TIMING_TCR_TAR_TRR(OFFSET(val, 3));
> +
> +	val = DIV_ROUND_UP(max(max(timings->tCS_min, timings->tCH_min),
> +			       max(timings->tALS_min, timings->tALH_min)),
> +			   period);
> +	reg |= TIMING_TCS(OFFSET(val, 2));
> +
> +	val = DIV_ROUND_UP(max(timings->tRP_min, timings->tREA_max) + 6000,
> +			   period);
> +	reg |= TIMING_TRP(OFFSET(val, 1)) | TIMING_TRP_RESP(OFFSET(val, 1));
> +
> +	reg |= TIMING_TWB(OFFSET(DIV_ROUND_UP(timings->tWB_max, period), 1));
> +	reg |= TIMING_TWHR(OFFSET(DIV_ROUND_UP(timings->tWHR_min, period), 1));
> +	reg |= TIMING_TWH(OFFSET(DIV_ROUND_UP(timings->tWH_min, period), 1));
> +	reg |= TIMING_TWP(OFFSET(DIV_ROUND_UP(timings->tWP_min, period), 1));
> +	reg |= TIMING_TRH(OFFSET(DIV_ROUND_UP(timings->tREH_min, period), 1));
> +
> +	writel_relaxed(reg, ctrl->regs + TIMING_1);
> +
> +	val = DIV_ROUND_UP(timings->tADL_min, period);
> +	reg = TIMING_TADL(OFFSET(val, 3));
> +
> +	writel_relaxed(reg, ctrl->regs + TIMING_2);
> +}
> +
> +static int tegra_nand_setup_data_interface(struct mtd_info *mtd, int csline,
> +					   const struct nand_data_interface *conf)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
> +	const struct nand_sdr_timings *timings;
> +
> +	timings = nand_get_sdr_timings(conf);
> +	if (IS_ERR(timings))
> +		return PTR_ERR(timings);
> +
> +	if (csline == NAND_DATA_IFACE_CHECK_ONLY)
> +		return 0;
> +
> +	tegra_nand_setup_timing(ctrl, timings);
> +
> +	return 0;
> +}
> +
> +
> +const int rs_strength_bootable[] = { 4 };
> +const int rs_strength[] = { 4, 6, 8 };
> +const int bch_strength_bootable[] = { 8, 16 };
> +const int bch_strength[] = { 4, 8, 14, 16 };

These const's shall be 'static'.

> +
> +static int tegra_nand_get_strength(struct nand_chip *chip, const int *strength,
> +				   int strength_len, int oobsize)
> +{
> +	bool maximize = chip->ecc.options & NAND_ECC_MAXIMIZE;
> +	int i;
> +
> +	/*
> +	 * Loop through available strengths. Backwards in case we try to
> +	 * maximize the BCH strength.
> +	 */
> +	for (i = 0; i < strength_len; i++) {
> +		int strength_sel, bytes_per_step, bytes_per_page;
> +
> +		if (maximize) {
> +			strength_sel = strength[strength_len - i - 1];
> +		} else {
> +			strength_sel = strength[i];
> +
> +			if (strength_sel < chip->ecc_strength_ds)
> +				continue;
> +		}
> +
> +		bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH * strength_sel,
> +					      BITS_PER_BYTE);
> +		bytes_per_page = round_up(bytes_per_step * chip->ecc.steps, 4);
> +
> +		/* Check whether strength fits OOB */
> +		if (bytes_per_page < (oobsize - SKIP_SPARE_BYTES))
> +			return strength_sel;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int tegra_nand_select_strength(struct nand_chip *chip, int oobsize)
> +{
> +	const int *strength;
> +	int strength_len;
> +
> +	switch (chip->ecc.algo) {
> +	case NAND_ECC_RS:
> +		if (chip->options & NAND_IS_BOOT_MEDIUM) {
> +			strength = rs_strength_bootable;
> +			strength_len = ARRAY_SIZE(rs_strength_bootable);
> +		} else {
> +			strength = rs_strength;
> +			strength_len = ARRAY_SIZE(rs_strength);
> +		}
> +		break;
> +	case NAND_ECC_BCH:
> +		if (chip->options & NAND_IS_BOOT_MEDIUM) {
> +			strength = bch_strength_bootable;
> +			strength_len = ARRAY_SIZE(bch_strength_bootable);
> +		} else {
> +			strength = bch_strength;
> +			strength_len = ARRAY_SIZE(bch_strength);
> +		}
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return tegra_nand_get_strength(chip, strength, strength_len, oobsize);
> +}
> +
> +static int tegra_nand_chips_init(struct device *dev,
> +				 struct tegra_nand_controller *ctrl)
> +{
> +	struct device_node *np = dev->of_node;
> +	struct device_node *np_nand;
> +	int nchips = of_get_child_count(np);
> +	struct tegra_nand_chip *nand;
> +	struct mtd_info *mtd;
> +	struct nand_chip *chip;
> +	unsigned long config, bch_config = 0;
> +	int bits_per_step;
> +	int ret;
> +
> +	if (nchips != 1) {
> +		dev_err(dev, "Currently only one NAND chip supported\n");
> +		return -EINVAL;
> +	}
> +
> +	np_nand = of_get_next_child(np, NULL);
> +
> +	nand = devm_kzalloc(dev, sizeof(*nand), GFP_KERNEL);
> +	if (!nand)
> +		return -ENOMEM;
> +
> +	nand->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_LOW);
> +
> +	if (IS_ERR(nand->wp_gpio)) {
> +		ret = PTR_ERR(nand->wp_gpio);
> +		dev_err(dev, "Failed to request WP GPIO: %d\n", ret);
> +		return ret;
> +	}
> +
> +	chip = &nand->chip;
> +	chip->controller = &ctrl->controller;
> +
> +	mtd = nand_to_mtd(chip);
> +
> +	mtd->dev.parent = dev;
> +	if (!mtd->name)
> +		mtd->name = "tegra_nand";
> +	mtd->owner = THIS_MODULE;
> +
> +	nand_set_flash_node(chip, np_nand);
> +
> +	chip->options = NAND_NO_SUBPAGE_WRITE | NAND_USE_BOUNCE_BUFFER;
> +	chip->exec_op = tegra_nand_exec_op;
> +	chip->select_chip = tegra_nand_select_chip;
> +	chip->setup_data_interface = tegra_nand_setup_data_interface;
> +
> +	ret = nand_scan_ident(mtd, 1, NULL);
> +	if (ret)
> +		return ret;
> +
> +	if (chip->bbt_options & NAND_BBT_USE_FLASH)
> +		chip->bbt_options |= NAND_BBT_NO_OOB;
> +
> +	chip->ecc.mode = NAND_ECC_HW;
> +	chip->ecc.size = 512;
> +	chip->ecc.steps = mtd->writesize / chip->ecc.size;
> +	if (chip->ecc_step_ds != 512) {
> +		dev_err(dev, "Unsupported step size %d\n", chip->ecc_step_ds);
> +		return -EINVAL;
> +	}
> +
> +	chip->ecc.read_page = tegra_nand_read_page_hwecc;
> +	chip->ecc.write_page = tegra_nand_write_page_hwecc;
> +
> +	config = readl_relaxed(ctrl->regs + CFG);
> +	config |= CFG_PIPE_EN | CFG_SKIP_SPARE | CFG_SKIP_SPARE_SIZE_4;
> +
> +	if (chip->options & NAND_BUSWIDTH_16)
> +		config |= CFG_BUS_WIDTH_16;
> +
> +	if (chip->ecc.algo == NAND_ECC_UNKNOWN) {
> +		if (mtd->writesize < 2048)
> +			chip->ecc.algo = NAND_ECC_RS;
> +		else
> +			chip->ecc.algo = NAND_ECC_BCH;
> +	}
> +
> +	if (chip->ecc.algo == NAND_ECC_BCH && mtd->writesize < 2048) {
> +		dev_err(dev, "BCH supportes 2K or 4K page size only\n");
> +		return -EINVAL;
> +	}
> +
> +	if (!chip->ecc.strength) {
> +		ret = tegra_nand_select_strength(chip, mtd->oobsize);
> +		if (ret < 0) {
> +			dev_err(dev, "No valid strenght found, minimum %d\n",
> +				chip->ecc_strength_ds);
> +			return ret;
> +		}
> +
> +		chip->ecc.strength = ret;
> +	}
> +
> +	switch (chip->ecc.algo) {
> +	case NAND_ECC_RS:
> +		bits_per_step = BITS_PER_STEP_RS * chip->ecc.strength;
> +		mtd_set_ooblayout(mtd, &tegra_nand_oob_rs_ops);
> +		switch (chip->ecc.strength) {
> +		case 4:
> +			config |= CFG_ECC_SEL | CFG_TVAL_4;
> +			break;
> +		case 6:
> +			config |= CFG_ECC_SEL | CFG_TVAL_6;
> +			break;
> +		case 8:
> +			config |= CFG_ECC_SEL | CFG_TVAL_8;
> +			break;
> +		default:
> +			dev_err(dev, "ECC strength %d not supported\n",
> +				chip->ecc.strength);
> +			return -EINVAL;
> +		}
> +		break;
> +	case NAND_ECC_BCH:
> +		bits_per_step = BITS_PER_STEP_BCH * chip->ecc.strength;
> +		mtd_set_ooblayout(mtd, &tegra_nand_oob_bch_ops);
> +		switch (chip->ecc.strength) {
> +		case 4:
> +			bch_config = BCH_TVAL_4;
> +			break;
> +		case 8:
> +			bch_config = BCH_TVAL_8;
> +			break;
> +		case 14:
> +			bch_config = BCH_TVAL_14;
> +			break;
> +		case 16:
> +			bch_config = BCH_TVAL_16;
> +			break;
> +		default:
> +			dev_err(dev, "ECC strength %d not supported\n",
> +				chip->ecc.strength);
> +			return -EINVAL;
> +		}
> +		break;
> +	default:
> +		dev_err(dev, "ECC algorithm not supported\n");
> +		return -EINVAL;
> +	}
> +
> +	dev_info(dev, "Using %s with strength %d per 512 byte step\n",
> +			chip->ecc.algo == NAND_ECC_BCH ? "BCH" : "RS",
> +			chip->ecc.strength);
> +
> +	chip->ecc.bytes = DIV_ROUND_UP(bits_per_step, BITS_PER_BYTE);
> +
> +	switch (mtd->writesize) {
> +	case 256:
> +		config |= CFG_PS_256;
> +		break;
> +	case 512:
> +		config |= CFG_PS_512;
> +		break;
> +	case 1024:
> +		config |= CFG_PS_1024;
> +		break;
> +	case 2048:
> +		config |= CFG_PS_2048;
> +		break;
> +	case 4096:
> +		config |= CFG_PS_4096;
> +		break;
> +	default:
> +		dev_err(dev, "Unsupported writesize %d\n", mtd->writesize);
> +		return -ENODEV;
> +	}
> +
> +	writel_relaxed(config, ctrl->regs + CFG);
> +	writel_relaxed(bch_config, ctrl->regs + BCH_CONFIG);
> +
> +	ret = nand_scan_tail(mtd);
> +	if (ret)
> +		return ret;
> +
> +	mtd_ooblayout_free(mtd, 0, &nand->tag);
> +
> +	config |= CFG_TAG_BYTE_SIZE(nand->tag.length - 1);
> +	writel_relaxed(config, ctrl->regs + CFG);
> +
> +	ret = mtd_device_register(mtd, NULL, 0);
> +	if (ret) {
> +		dev_err(dev, "Failed to register mtd device: %d\n", ret);
> +		nand_cleanup(chip);
> +		return ret;
> +	}
> +
> +	ctrl->chip = chip;
> +
> +	return 0;
> +}
> +
> +static int tegra_nand_probe(struct platform_device *pdev)
> +{
> +	struct reset_control *rst;
> +	struct tegra_nand_controller *ctrl;
> +	struct resource *res;
> +	unsigned long reg;
> +	int irq, err = 0;
> +
> +	ctrl = devm_kzalloc(&pdev->dev, sizeof(*ctrl), GFP_KERNEL);
> +	if (!ctrl)
> +		return -ENOMEM;
> +
> +	ctrl->dev = &pdev->dev;
> +	nand_hw_control_init(&ctrl->controller);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	ctrl->regs = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(ctrl->regs))
> +		return PTR_ERR(ctrl->regs);
> +
> +	rst = devm_reset_control_get(&pdev->dev, "nand");
> +	if (IS_ERR(rst))
> +		return PTR_ERR(rst);
> +
> +	ctrl->clk = devm_clk_get(&pdev->dev, "nand");
> +	if (IS_ERR(ctrl->clk))
> +		return PTR_ERR(ctrl->clk);
> +
> +	err = clk_prepare_enable(ctrl->clk);
> +	if (err)
> +		return err;
> +
> +	err = reset_control_reset(rst);
> +	if (err)
> +		goto err_disable_clk;
> +
> +	reg = HWSTATUS_RDSTATUS_MASK(1) | HWSTATUS_RDSTATUS_VALUE(0) |
> +		HWSTATUS_RBSY_MASK(NAND_STATUS_READY) |
> +		HWSTATUS_RBSY_VALUE(NAND_STATUS_READY);
> +	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
> +	writel_relaxed(reg, ctrl->regs + HWSTATUS_MASK);
> +
> +	init_completion(&ctrl->command_complete);
> +	init_completion(&ctrl->dma_complete);
> +
> +	/* clear interrupts */
> +	reg = readl_relaxed(ctrl->regs + ISR);
> +	writel_relaxed(reg, ctrl->regs + ISR);
> +
> +	irq = platform_get_irq(pdev, 0);
> +	err = devm_request_irq(&pdev->dev, irq, tegra_nand_irq, 0,
> +			       dev_name(&pdev->dev), ctrl);
> +	if (err)
> +		goto err_disable_clk;
> +
> +	writel_relaxed(DMA_CTRL_IS_DONE, ctrl->regs + DMA_CTRL);
> +
> +	/* enable interrupts */
> +	reg = IER_UND | IER_OVR | IER_CMD_DONE | IER_GIE;
> +	writel_relaxed(reg, ctrl->regs + IER);
> +
> +	/* reset config */
> +	writel_relaxed(0, ctrl->regs + CFG);
> +
> +	err = tegra_nand_chips_init(ctrl->dev, ctrl);
> +	if (err)
> +		goto err_disable_clk;
> +
> +	platform_set_drvdata(pdev, ctrl);
> +
> +	return 0;
> +
> +err_disable_clk:
> +	clk_disable_unprepare(ctrl->clk);
> +	return err;
> +}
> +
> +static int tegra_nand_remove(struct platform_device *pdev)
> +{
> +	struct tegra_nand_controller *ctrl = platform_get_drvdata(pdev);
> +
> +	nand_release(nand_to_mtd(ctrl->chip));
> +
> +	clk_disable_unprepare(ctrl->clk);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id tegra_nand_of_match[] = {
> +	{ .compatible = "nvidia,tegra20-nand" },
> +	{ /* sentinel */ }
> +};
> +
> +static struct platform_driver tegra_nand_driver = {
> +	.driver = {
> +		.name = "tegra-nand",
> +		.of_match_table = tegra_nand_of_match,
> +	},
> +	.probe = tegra_nand_probe,
> +	.remove = tegra_nand_remove,
> +};
> +module_platform_driver(tegra_nand_driver);
> +
> +MODULE_DESCRIPTION("NVIDIA Tegra NAND driver");
> +MODULE_AUTHOR("Thierry Reding <thierry.reding@nvidia.com>");
> +MODULE_AUTHOR("Lucas Stach <dev@lynxeye.de>");
> +MODULE_AUTHOR("Stefan Agner <stefan@agner.ch>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_DEVICE_TABLE(of, tegra_nand_of_match);
> 

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Am Freitag, den 01.06.2018, 00:16 +0200 schrieb Stefan Agner:
> Add support for the NAND flash controller found on NVIDIA
> Tegra 2 SoCs. This implementation does not make use of the
> command queue feature. Regular operations/data transfers are
> done in PIO mode. Page read/writes with hardware ECC make
> use of the DMA for data transfer.
> 
> Signed-off-by: Lucas Stach <dev@lynxeye.de>
> Signed-off-by: Stefan Agner <stefan@agner.ch>
> ---
>  MAINTAINERS                       |    7 +
>  drivers/mtd/nand/raw/Kconfig      |    6 +
>  drivers/mtd/nand/raw/Makefile     |    1 +
>  drivers/mtd/nand/raw/tegra_nand.c | 1143
> +++++++++++++++++++++++++++++
>  4 files changed, 1157 insertions(+)
>  create mode 100644 drivers/mtd/nand/raw/tegra_nand.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 58b9861ccf99..c2e5571c85d4 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -13844,6 +13844,13 @@ M:	Laxman Dewangan <ldewangan@nvidia.
> com>
>  S:	Supported
>  F:	drivers/input/keyboard/tegra-kbc.c
>  
> +TEGRA NAND DRIVER
> +M:	Stefan Agner <stefan@agner.ch>
> +M:	Lucas Stach <dev@lynxeye.de>
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/mtd/nvidia-tegra20-
> nand.txt
> +F:	drivers/mtd/nand/raw/tegra_nand.c
> +
>  TEGRA PWM DRIVER
>  M:	Thierry Reding <thierry.reding@gmail.com>
>  S:	Supported
> diff --git a/drivers/mtd/nand/raw/Kconfig
> b/drivers/mtd/nand/raw/Kconfig
> index 19a2b283fbbe..e9093f52371e 100644
> --- a/drivers/mtd/nand/raw/Kconfig
> +++ b/drivers/mtd/nand/raw/Kconfig
> @@ -534,4 +534,10 @@ config MTD_NAND_MTK
>  	  Enables support for NAND controller on MTK SoCs.
>  	  This controller is found on mt27xx, mt81xx, mt65xx SoCs.
>  
> +config MTD_NAND_TEGRA
> +	tristate "Support for NAND controller on NVIDIA Tegra"
> +	depends on ARCH_TEGRA || COMPILE_TEST
> +	help
> +	  Enables support for NAND flash controller on NVIDIA Tegra
> SoC.
> +
>  endif # MTD_NAND
> diff --git a/drivers/mtd/nand/raw/Makefile
> b/drivers/mtd/nand/raw/Makefile
> index 165b7ef9e9a1..d5a5f9832b88 100644
> --- a/drivers/mtd/nand/raw/Makefile
> +++ b/drivers/mtd/nand/raw/Makefile
> @@ -56,6 +56,7 @@ obj-$(CONFIG_MTD_NAND_HISI504)	        +=
> hisi504_nand.o
>  obj-$(CONFIG_MTD_NAND_BRCMNAND)		+= brcmnand/
>  obj-$(CONFIG_MTD_NAND_QCOM)		+= qcom_nandc.o
>  obj-$(CONFIG_MTD_NAND_MTK)		+= mtk_ecc.o mtk_nand.o
> +obj-$(CONFIG_MTD_NAND_TEGRA)		+= tegra_nand.o
>  
>  nand-objs := nand_base.o nand_bbt.o nand_timings.o nand_ids.o
>  nand-objs += nand_amd.o
> diff --git a/drivers/mtd/nand/raw/tegra_nand.c
> b/drivers/mtd/nand/raw/tegra_nand.c
> new file mode 100644
> index 000000000000..e9664f2938a3
> --- /dev/null
> +++ b/drivers/mtd/nand/raw/tegra_nand.c
> @@ -0,0 +1,1143 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2018 Stefan Agner <stefan@agner.ch>
> + * Copyright (C) 2014-2015 Lucas Stach <dev@lynxeye.de>
> + * Copyright (C) 2012 Avionic Design GmbH
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/completion.h>
> +#include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/err.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/mtd/partitions.h>
> +#include <linux/mtd/rawnand.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +
> +#define CMD					0x00
> +#define   CMD_GO				BIT(31)
> +#define   CMD_CLE				BIT(30)
> +#define   CMD_ALE				BIT(29)
> +#define   CMD_PIO				BIT(28)
> +#define   CMD_TX				BIT(27)
> +#define   CMD_RX				BIT(26)
> +#define   CMD_SEC_CMD				BIT(25)
> +#define   CMD_AFT_DAT				BIT(24)
> +#define   CMD_TRANS_SIZE(x)			(((x - 1) & 0xf)
> << 20)
> +#define   CMD_A_VALID				BIT(19)
> +#define   CMD_B_VALID				BIT(18)
> +#define   CMD_RD_STATUS_CHK			BIT(17)
> +#define   CMD_RBSY_CHK				BIT(16)
> +#define   CMD_CE(x)				BIT((8 + ((x) &
> 0x7)))
> +#define   CMD_CLE_SIZE(x)			(((x - 1) & 0x3) <<
> 4)
> +#define   CMD_ALE_SIZE(x)			(((x - 1) & 0xf) <<
> 0)
> +
> +#define STATUS					0x04
> +
> +#define ISR					0x08
> +#define   ISR_CORRFAIL_ERR			BIT(24)
> +#define   ISR_UND				BIT(7)
> +#define   ISR_OVR				BIT(6)
> +#define   ISR_CMD_DONE				BIT(5)
> +#define   ISR_ECC_ERR				BIT(4)
> +
> +#define IER					0x0c
> +#define   IER_ERR_TRIG_VAL(x)			(((x) & 0xf) <<
> 16)
> +#define   IER_UND				BIT(7)
> +#define   IER_OVR				BIT(6)
> +#define   IER_CMD_DONE				BIT(5)
> +#define   IER_ECC_ERR				BIT(4)
> +#define   IER_GIE				BIT(0)
> +
> +#define CFG					0x10
> +#define   CFG_HW_ECC				BIT(31)
> +#define   CFG_ECC_SEL				BIT(30)
> +#define   CFG_ERR_COR				BIT(29)
> +#define   CFG_PIPE_EN				BIT(28)
> +#define   CFG_TVAL_4				(0 << 24)
> +#define   CFG_TVAL_6				(1 << 24)
> +#define   CFG_TVAL_8				(2 << 24)
> +#define   CFG_SKIP_SPARE			BIT(23)
> +#define   CFG_BUS_WIDTH_16			BIT(21)
> +#define   CFG_COM_BSY				BIT(20)
> +#define   CFG_PS_256				(0 << 16)
> +#define   CFG_PS_512				(1 << 16)
> +#define   CFG_PS_1024				(2 << 16)
> +#define   CFG_PS_2048				(3 << 16)
> +#define   CFG_PS_4096				(4 << 16)
> +#define   CFG_SKIP_SPARE_SIZE_4			(0 << 14)
> +#define   CFG_SKIP_SPARE_SIZE_8			(1 << 14)
> +#define   CFG_SKIP_SPARE_SIZE_12		(2 << 14)
> +#define   CFG_SKIP_SPARE_SIZE_16		(3 << 14)
> +#define   CFG_TAG_BYTE_SIZE(x)			((x) & 0xff)
> +
> +#define TIMING_1				0x14
> +#define   TIMING_TRP_RESP(x)			(((x) & 0xf) <<
> 28)
> +#define   TIMING_TWB(x)				(((x) & 0xf)
> << 24)
> +#define   TIMING_TCR_TAR_TRR(x)			(((x) & 0xf)
> << 20)
> +#define   TIMING_TWHR(x)			(((x) & 0xf) << 16)
> +#define   TIMING_TCS(x)				(((x) & 0x3)
> << 14)
> +#define   TIMING_TWH(x)				(((x) & 0x3)
> << 12)
> +#define   TIMING_TWP(x)				(((x) & 0xf)
> <<  8)
> +#define   TIMING_TRH(x)				(((x) & 0x3)
> <<  4)
> +#define   TIMING_TRP(x)				(((x) & 0xf)
> <<  0)
> +
> +#define RESP					0x18
> +
> +#define TIMING_2				0x1c
> +#define   TIMING_TADL(x)			((x) & 0xf)
> +
> +#define CMD_1					0x20
> +#define CMD_2					0x24
> +#define ADDR_1					0x28
> +#define ADDR_2					0x2c
> +
> +#define DMA_CTRL				0x30
> +#define   DMA_CTRL_GO				BIT(31)
> +#define   DMA_CTRL_IN				(0 << 30)
> +#define   DMA_CTRL_OUT				BIT(30)
> +#define   DMA_CTRL_PERF_EN			BIT(29)
> +#define   DMA_CTRL_IE_DONE			BIT(28)
> +#define   DMA_CTRL_REUSE			BIT(27)
> +#define   DMA_CTRL_BURST_1			(2 << 24)
> +#define   DMA_CTRL_BURST_4			(3 << 24)
> +#define   DMA_CTRL_BURST_8			(4 << 24)
> +#define   DMA_CTRL_BURST_16			(5 << 24)
> +#define   DMA_CTRL_IS_DONE			BIT(20)
> +#define   DMA_CTRL_EN_A				BIT(2)
> +#define   DMA_CTRL_EN_B				BIT(1)
> +
> +#define DMA_CFG_A				0x34
> +#define DMA_CFG_B				0x38
> +
> +#define FIFO_CTRL				0x3c
> +#define   FIFO_CTRL_CLR_ALL			BIT(3)
> +
> +#define DATA_PTR				0x40
> +#define TAG_PTR					0x44
> +#define ECC_PTR					0x48
> +
> +#define DEC_STATUS				0x4c
> +#define   DEC_STATUS_A_ECC_FAIL			BIT(1)
> +#define   DEC_STATUS_ERR_COUNT_MASK		0x00ff0000
> +#define   DEC_STATUS_ERR_COUNT_SHIFT		16
> +
> +#define HWSTATUS_CMD				0x50
> +#define HWSTATUS_MASK				0x54
> +#define   HWSTATUS_RDSTATUS_MASK(x)		(((x) & 0xff) <<
> 24)
> +#define   HWSTATUS_RDSTATUS_VALUE(x)		(((x) & 0xff) <<
> 16)
> +#define   HWSTATUS_RBSY_MASK(x)			(((x) & 0xff)
> << 8)
> +#define   HWSTATUS_RBSY_VALUE(x)		(((x) & 0xff) << 0)
> +
> +#define BCH_CONFIG				0xcc
> +#define   BCH_ENABLE				BIT(0)
> +#define   BCH_TVAL_4				(0 << 4)
> +#define   BCH_TVAL_8				(1 << 4)
> +#define   BCH_TVAL_14				(2 << 4)
> +#define   BCH_TVAL_16				(3 << 4)
> +
> +#define DEC_STAT_RESULT				0xd0
> +#define DEC_STAT_BUF				0xd4
> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_MASK	0xff000000
> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_SHIFT	24
> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_MASK	0x00ff0000
> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT	16
> +#define   DEC_STAT_BUF_MAX_CORR_CNT_MASK	0x00001f00
> +#define   DEC_STAT_BUF_MAX_CORR_CNT_SHIFT	8
> +
> +#define OFFSET(val, off)		((val) < (off) ? 0 : (val) -
> (off))
> +
> +#define SKIP_SPARE_BYTES	4
> +#define BITS_PER_STEP_RS	18
> +#define BITS_PER_STEP_BCH	13
> +
> +struct tegra_nand_controller {
> +	struct nand_hw_control controller;
> +	void __iomem *regs;
> +	struct clk *clk;
> +	struct device *dev;
> +	struct completion command_complete;
> +	struct completion dma_complete;
> +	bool last_read_error;
> +	int cur_chip;
> +	struct nand_chip *chip;
> +};
> +
> +struct tegra_nand_chip {
> +	struct nand_chip chip;
> +	struct gpio_desc *wp_gpio;
> +	struct mtd_oob_region tag;
> +};
> +
> +static inline struct tegra_nand_controller *to_tegra_ctrl(
> +						struct
> nand_hw_control *hw_ctrl)
> +{
> +	return container_of(hw_ctrl, struct tegra_nand_controller,
> controller);
> +}
> +
> +static inline struct tegra_nand_chip *to_tegra_chip(struct nand_chip
> *chip)
> +{
> +	return container_of(chip, struct tegra_nand_chip, chip);
> +}
> +
> +static int tegra_nand_ooblayout_rs_ecc(struct mtd_info *mtd, int
> section,
> +				       struct mtd_oob_region
> *oobregion)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS * chip-
> >ecc.strength,
> +					  BITS_PER_BYTE);
> +
> +	if (section > 0)
> +		return -ERANGE;
> +
> +	oobregion->offset = SKIP_SPARE_BYTES;
> +	oobregion->length = round_up(bytes_per_step * chip-
> >ecc.steps, 4);
> +
> +	return 0;
> +}
> +
> +static int tegra_nand_ooblayout_rs_free(struct mtd_info *mtd, int
> section,
> +					struct mtd_oob_region
> *oobregion)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS * chip-
> >ecc.strength,
> +					  BITS_PER_BYTE);
> +
> +	if (section > 0)
> +		return -ERANGE;
> +
> +	oobregion->offset = SKIP_SPARE_BYTES +
> +			    round_up(bytes_per_step * chip-
> >ecc.steps, 4);
> +	oobregion->length = mtd->oobsize - oobregion->offset;
> +
> +	return 0;
> +}
> +
> +static const struct mtd_ooblayout_ops tegra_nand_oob_rs_ops = {
> +	.ecc = tegra_nand_ooblayout_rs_ecc,
> +	.free = tegra_nand_ooblayout_rs_free,
> +};
> +
> +static int tegra_nand_ooblayout_bch_ecc(struct mtd_info *mtd, int
> section,
> +				       struct mtd_oob_region
> *oobregion)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH * chip-
> >ecc.strength,
> +					  BITS_PER_BYTE);
> +
> +	if (section > 0)
> +		return -ERANGE;
> +
> +	oobregion->offset = SKIP_SPARE_BYTES;
> +	oobregion->length = round_up(bytes_per_step * chip-
> >ecc.steps, 4);
> +
> +	return 0;
> +}
> +
> +static int tegra_nand_ooblayout_bch_free(struct mtd_info *mtd, int
> section,
> +					struct mtd_oob_region
> *oobregion)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH * chip-
> >ecc.strength,
> +					  BITS_PER_BYTE);
> +
> +	if (section > 0)
> +		return -ERANGE;
> +
> +	oobregion->offset = SKIP_SPARE_BYTES +
> +			    round_up(bytes_per_step * chip-
> >ecc.steps, 4);
> +	oobregion->length = mtd->oobsize - oobregion->offset;
> +
> +	return 0;
> +}
> +
> +/*
> + * Layout with tag bytes is
> + *
> + * ---------------------------------------------------------------
> -----------
> + * | main area                       | skip bytes | tag bytes |
> parity | .. |
> + * ---------------------------------------------------------------
> -----------
> + *
> + * If not tag bytes are written, parity moves right after skip
> bytes!
> + */
> +static const struct mtd_ooblayout_ops tegra_nand_oob_bch_ops = {
> +	.ecc = tegra_nand_ooblayout_bch_ecc,
> +	.free = tegra_nand_ooblayout_bch_free,
> +};
> +
> +static irqreturn_t tegra_nand_irq(int irq, void *data)
> +{
> +	struct tegra_nand_controller *ctrl = data;
> +	u32 isr, dma;
> +
> +	isr = readl_relaxed(ctrl->regs + ISR);
> +	dma = readl_relaxed(ctrl->regs + DMA_CTRL);
> +	dev_dbg(ctrl->dev, "isr %08x\n", isr);
> +
> +	if (!isr && !(dma & DMA_CTRL_IS_DONE))
> +		return IRQ_NONE;
> +
> +	/*
> +	 * The bit name is somewhat missleading: This is also set
> when
> +	 * HW ECC was successful. The data sheet states:
> +	 * Correctable OR Un-correctable errors occurred in the DMA
> transfer...
> +	 */
> +	if (isr & ISR_CORRFAIL_ERR)
> +		ctrl->last_read_error = true;
> +
> +	if (isr & ISR_CMD_DONE)
> +		complete(&ctrl->command_complete);
> +
> +	if (isr & ISR_UND)
> +		dev_err(ctrl->dev, "FIFO underrun\n");
> +
> +	if (isr & ISR_OVR)
> +		dev_err(ctrl->dev, "FIFO overrun\n");
> +
> +	/* handle DMA interrupts */
> +	if (dma & DMA_CTRL_IS_DONE) {
> +		writel_relaxed(dma, ctrl->regs + DMA_CTRL);
> +		complete(&ctrl->dma_complete);
> +	}
> +
> +	/* clear interrupts */
> +	writel_relaxed(isr, ctrl->regs + ISR);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static const char * const tegra_nand_reg_names[] = {
> +	"COMMAND",
> +	"STATUS",
> +	"ISR",
> +	"IER",
> +	"CONFIG",
> +	"TIMING",
> +	NULL,
> +	"TIMING2",
> +	"CMD_REG1",
> +	"CMD_REG2",
> +	"ADDR_REG1",
> +	"ADDR_REG2",
> +	"DMA_MST_CTRL",
> +	"DMA_CFG_A",
> +	"DMA_CFG_B",
> +	"FIFO_CTRL",
> +};
> +
> +static void tegra_nand_dump_reg(struct tegra_nand_controller *ctrl)
> +{
> +	u32 reg;
> +	int i;
> +
> +	dev_err(ctrl->dev, "Tegra NAND controller register dump\n");
> +	for (i = 0; i < ARRAY_SIZE(tegra_nand_reg_names); i++) {
> +		const char *reg_name = tegra_nand_reg_names[i];
> +
> +		if (!reg_name)
> +			continue;
> +
> +		reg = readl_relaxed(ctrl->regs + (i * 4));
> +		dev_err(ctrl->dev, "%s: 0x%08x\n", reg_name, reg);
> +	}
> +}
> +
> +static int tegra_nand_cmd(struct nand_chip *chip,
> +			 const struct nand_subop *subop)
> +{
> +	const struct nand_op_instr *instr;
> +	const struct nand_op_instr *instr_data_in = NULL;
> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip-
> >controller);
> +	unsigned int op_id, size = 0, offset = 0;
> +	bool first_cmd = true;
> +	u32 reg, cmd = 0;
> +	int ret;
> +
> +	for (op_id = 0; op_id < subop->ninstrs; op_id++) {
> +		unsigned int naddrs, i;
> +		const u8 *addrs;
> +		u32 addr1 = 0, addr2 = 0;
> +
> +		instr = &subop->instrs[op_id];
> +
> +		switch (instr->type) {
> +		case NAND_OP_CMD_INSTR:
> +			if (first_cmd) {
> +				cmd |= CMD_CLE;
> +				writel_relaxed(instr-
> >ctx.cmd.opcode,
> +					       ctrl->regs + CMD_1);
> +			} else {
> +				cmd |= CMD_SEC_CMD;
> +				writel_relaxed(instr-
> >ctx.cmd.opcode,
> +					       ctrl->regs + CMD_2);
> +			}
> +			first_cmd = false;
> +			break;
> +		case NAND_OP_ADDR_INSTR:
> +			offset =
> nand_subop_get_addr_start_off(subop, op_id);
> +			naddrs = nand_subop_get_num_addr_cyc(subop,
> op_id);
> +			addrs = &instr->ctx.addr.addrs[offset];
> +
> +			cmd |= CMD_ALE | CMD_ALE_SIZE(naddrs);
> +			for (i = 0; i < min_t(unsigned int, 4,
> naddrs); i++)
> +				addr1 |= *addrs++ << (BITS_PER_BYTE
> * i);
> +			naddrs -= i;
> +			for (i = 0; i < min_t(unsigned int, 4,
> naddrs); i++)
> +				addr2 |= *addrs++ << (BITS_PER_BYTE
> * i);
> +			writel_relaxed(addr1, ctrl->regs + ADDR_1);
> +			writel_relaxed(addr2, ctrl->regs + ADDR_2);
> +			break;
> +
> +		case NAND_OP_DATA_IN_INSTR:
> +			size = nand_subop_get_data_len(subop,
> op_id);
> +			offset =
> nand_subop_get_data_start_off(subop, op_id);
> +
> +			cmd |= CMD_TRANS_SIZE(size) | CMD_PIO |
> CMD_RX |
> +				CMD_A_VALID;
> +
> +			instr_data_in = instr;
> +			break;
> +
> +		case NAND_OP_DATA_OUT_INSTR:
> +			size = nand_subop_get_data_len(subop,
> op_id);
> +			offset =
> nand_subop_get_data_start_off(subop, op_id);
> +
> +			cmd |= CMD_TRANS_SIZE(size) | CMD_PIO |
> CMD_TX |
> +				CMD_A_VALID;
> +
> +			memcpy(&reg, instr->ctx.data.buf.out +
> offset, size);
> +			writel_relaxed(reg, ctrl->regs + RESP);
> +
> +			break;
> +		case NAND_OP_WAITRDY_INSTR:
> +			cmd |= CMD_RBSY_CHK;
> +			break;
> +
> +		}
> +	}
> +
> +	cmd |= CMD_GO | CMD_CE(ctrl->cur_chip);
> +	writel_relaxed(cmd, ctrl->regs + CMD);
> +	ret = wait_for_completion_timeout(&ctrl->command_complete,
> +					  msecs_to_jiffies(500));
> +	if (!ret) {
> +		dev_err(ctrl->dev, "CMD timeout\n");
> +		tegra_nand_dump_reg(ctrl);
> +		return -ETIMEDOUT;
> +	}
> +
> +	if (instr_data_in) {
> +		reg = readl_relaxed(ctrl->regs + RESP);
> +		memcpy(instr_data_in->ctx.data.buf.in + offset,
> &reg, size);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct nand_op_parser tegra_nand_op_parser =
> NAND_OP_PARSER(
> +	NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
> +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
> +		NAND_OP_PARSER_PAT_ADDR_ELEM(true, 8),
> +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
> +		NAND_OP_PARSER_PAT_WAITRDY_ELEM(true)),
> +	NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
> +		NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, 4)),
> +	NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
> +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
> +		NAND_OP_PARSER_PAT_ADDR_ELEM(true, 8),
> +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
> +		NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
> +		NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, 4)),
> +	);
> +
> +static int tegra_nand_exec_op(struct nand_chip *chip,
> +			     const struct nand_operation *op,
> +			     bool check_only)
> +{
> +	return nand_op_parser_exec_op(chip, &tegra_nand_op_parser,
> op,
> +				      check_only);
> +}
> +static void tegra_nand_select_chip(struct mtd_info *mtd, int
> chip_nr)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip-
> >controller);
> +
> +	ctrl->cur_chip = chip_nr;
> +}
> +
> +static void tegra_nand_hw_ecc(struct tegra_nand_controller *ctrl,
> +			      struct nand_chip *chip, bool enable)
> +{
> +	u32 reg;
> +
> +	switch (chip->ecc.algo) {
> +	case NAND_ECC_RS:
> +		reg = readl_relaxed(ctrl->regs + CFG);
> +		if (enable)
> +			reg |= CFG_HW_ECC | CFG_ERR_COR;
> +		else
> +			reg &= ~(CFG_HW_ECC | CFG_ERR_COR);
> +		writel_relaxed(reg, ctrl->regs + CFG);
> +		break;
> +	case NAND_ECC_BCH:
> +		reg = readl_relaxed(ctrl->regs + BCH_CONFIG);
> +		if (enable)
> +			reg |= BCH_ENABLE;
> +		else
> +			reg &= ~BCH_ENABLE;
> +		writel_relaxed(reg, ctrl->regs + BCH_CONFIG);
> +		break;
> +	default:
> +		dev_err(ctrl->dev, "Unsupported hardware ECC
> algorithm\n");
> +		break;
> +	}
> +}
> +
> +static int tegra_nand_page_xfer(struct mtd_info *mtd, struct
> nand_chip *chip,
> +				void *buf, int oob_required, int
> page,
> +				bool read)
> +{
> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip-
> >controller);
> +	struct tegra_nand_chip *nand = to_tegra_chip(chip);
> +	enum dma_data_direction dir = read ? DMA_FROM_DEVICE :
> DMA_TO_DEVICE;
> +	dma_addr_t dma_addr;
> +	u32 cmd, dma_ctrl;
> +	int ret, dma_len;
> +
> +	if (read) {
> +		writel_relaxed(NAND_CMD_READ0, ctrl->regs + CMD_1);
> +		writel_relaxed(NAND_CMD_READSTART, ctrl->regs +
> CMD_2);
> +	} else {
> +		writel_relaxed(NAND_CMD_SEQIN, ctrl->regs + CMD_1);
> +		writel_relaxed(NAND_CMD_PAGEPROG, ctrl->regs +
> CMD_2);
> +	}
> +	cmd = CMD_CLE | CMD_SEC_CMD;
> +
> +	/* Lower 16-bits are column, always 0 */
> +	writel_relaxed(page << 16, ctrl->regs + ADDR_1);
> +
> +	if (chip->options & NAND_ROW_ADDR_3) {
> +		writel_relaxed(page >> 16, ctrl->regs + ADDR_2);
> +		cmd |= CMD_ALE | CMD_ALE_SIZE(5);
> +	} else {
> +		cmd |= CMD_ALE | CMD_ALE_SIZE(4);
> +	}
> +
> +	dma_len = mtd->writesize + (oob_required ? mtd->oobsize :
> 0);
> +	dma_addr = dma_map_single(ctrl->dev, buf, dma_len, dir);
> +	ret = dma_mapping_error(ctrl->dev, dma_addr);
> +	if (ret) {
> +		dev_err(ctrl->dev, "dma mapping error\n");
> +		return -EINVAL;
> +	}
> +
> +	writel_relaxed(mtd->writesize - 1, ctrl->regs + DMA_CFG_A);
> +	writel_relaxed(dma_addr, ctrl->regs + DATA_PTR);
> +
> +	if (oob_required) {
> +		dma_addr_t dma_addr_tag = dma_addr + mtd->writesize;
> +
> +		writel_relaxed(nand->tag.length - 1, ctrl->regs +
> DMA_CFG_B);
> +		writel_relaxed(dma_addr_tag + nand->tag.offset,
> +			       ctrl->regs + TAG_PTR);
> +	} else {
> +		writel_relaxed(0, ctrl->regs + DMA_CFG_B);
> +		writel_relaxed(0, ctrl->regs + TAG_PTR);
> +	}
> +
> +	dma_ctrl = DMA_CTRL_GO | DMA_CTRL_PERF_EN |
> +		   DMA_CTRL_IE_DONE | DMA_CTRL_IS_DONE |
> +		   DMA_CTRL_BURST_16 | DMA_CTRL_EN_A;
> +	if (oob_required)
> +		dma_ctrl |= DMA_CTRL_EN_B;
> +	if (read)
> +		dma_ctrl |= DMA_CTRL_IN | DMA_CTRL_REUSE;
> +	else
> +		dma_ctrl |= DMA_CTRL_OUT;
> +
> +	writel_relaxed(dma_ctrl, ctrl->regs + DMA_CTRL);
> +
> +	cmd |= CMD_GO | CMD_RBSY_CHK | CMD_TRANS_SIZE(9) |
> +	       CMD_CE(ctrl->cur_chip) | CMD_A_VALID;
> +	if (oob_required)
> +		cmd |= CMD_B_VALID;
> +	if (read)
> +		cmd |= CMD_RX;
> +	else
> +		cmd |= CMD_TX | CMD_AFT_DAT;
> +
> +	writel_relaxed(cmd, ctrl->regs + CMD);
> +
> +	ret = wait_for_completion_timeout(&ctrl->command_complete,
> +					  msecs_to_jiffies(500));
> +	if (!ret) {
> +		dev_err(ctrl->dev, "CMD timeout\n");
> +		tegra_nand_dump_reg(ctrl);
> +		ret = -ETIMEDOUT;
> +		goto err_unmap_dma;
> +	}
> +
> +	ret = wait_for_completion_timeout(&ctrl->dma_complete,
> +					  msecs_to_jiffies(500));
> +	if (!ret) {
> +		dev_err(ctrl->dev, "DMA timeout\n");
> +		tegra_nand_dump_reg(ctrl);
> +		ret = -ETIMEDOUT;
> +		goto err_unmap_dma;
> +	}
> +	ret = 0;
> +
> +err_unmap_dma:
> +	dma_unmap_single(ctrl->dev, dma_addr, dma_len, dir);
> +
> +	return ret;
> +}
> +
> +static int tegra_nand_read_page_hwecc(struct mtd_info *mtd,
> +				      struct nand_chip *chip,
> +				      uint8_t *buf, int
> oob_required, int page)
> +{
> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip-
> >controller);
> +	u32 dec_stat, max_corr_cnt;
> +	unsigned long fail_sec_flag;
> +	int ret;
> +
> +	tegra_nand_hw_ecc(ctrl, chip, true);
> +	ret = tegra_nand_page_xfer(mtd, chip, buf, oob_required,
> page, true);
> +	tegra_nand_hw_ecc(ctrl, chip, false);
> +	if (ret)
> +		return ret;
> +
> +	/* No correctable or un-correctable errors, page must have 0
> bitflips */
> +	if (!ctrl->last_read_error)
> +		return 0;
> +
> +	/*
> +	 * Correctable or un-correctable errors occurred. Use
> DEC_STAT_BUF
> +	 * which contains information for all ECC selections.
> +	 *
> +	 * Note that since we do not use Command Queues DEC_RESULT
> does not
> +	 * state the number of pages we can read from the
> DEC_STAT_BUF. But
> +	 * since CORRFAIL_ERR did occur during page read we do have
> a valid
> +	 * result in DEC_STAT_BUF.
> +	 */
> +	ctrl->last_read_error = false;
> +	dec_stat = readl_relaxed(ctrl->regs + DEC_STAT_BUF);
> +
> +	fail_sec_flag = (dec_stat & DEC_STAT_BUF_FAIL_SEC_FLAG_MASK)
> >>
> +			DEC_STAT_BUF_FAIL_SEC_FLAG_SHIFT;
> +
> +	max_corr_cnt = (dec_stat & DEC_STAT_BUF_MAX_CORR_CNT_MASK)
> >>
> +		       DEC_STAT_BUF_MAX_CORR_CNT_SHIFT;
> +
> +	if (fail_sec_flag) {
> +		int bit, max_bitflips = 0;
> +
> +		/*
> +		 * Check if all sectors in a page failed. If only
> some failed
> +		 * its definitly not an erased page and we can
> return error
> +		 * stats right away.
> +		 *
> +		 * E.g. controller might return fail_sec_flag with
> 0x4, which
> +		 * would mean only the third sector failed to
> correct.
> +		 */
> +		if (fail_sec_flag ^ GENMASK(chip->ecc.steps - 1, 0))
> {
> +			mtd->ecc_stats.failed +=
> hweight8(fail_sec_flag);
> +			return max_corr_cnt;
> +		}
> +
> +		/*
> +		 * All sectors failed to correct, but the ECC isn't
> smart
> +		 * enough to figure out if a page is really
> completely erased.
> +		 * We check the read data here to figure out if it's
> a
> +		 * legitimate ECC error or only an erased page.
> +		 */
> +		for_each_set_bit(bit, &fail_sec_flag, chip-
> >ecc.steps) {
> +			u8 *data = buf + (chip->ecc.size * bit);
> +
> +			ret = nand_check_erased_ecc_chunk(data,
> chip->ecc.size,
> +							  NULL, 0,
> +							  NULL, 0,
> +							  chip-
> >ecc.strength);
> +			if (ret < 0)
> +				mtd->ecc_stats.failed++;
> +			else
> +				max_bitflips = max(ret,
> max_bitflips);
> +		}
> +
> +		return max_t(unsigned int, max_corr_cnt,
> max_bitflips);
> +	} else {
> +		int corr_sec_flag;
> +
> +		corr_sec_flag = (dec_stat &
> DEC_STAT_BUF_CORR_SEC_FLAG_MASK) >>
> +				DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT;
> +
> +		/*
> +		 * The value returned in the register is the maximum
> of
> +		 * bitflips encountered in any of the ECC regions.
> As there is
> +		 * no way to get the number of bitflips in a
> specific regions
> +		 * we are not able to deliver correct stats but
> instead
> +		 * overestimate the number of corrected bitflips by
> assuming
> +		 * that all regions where errors have been corrected
> +		 * encountered the maximum number of bitflips.
> +		 */
> +		mtd->ecc_stats.corrected += max_corr_cnt *
> hweight8(corr_sec_flag);
> +
> +		return max_corr_cnt;
> +	}
> +
> +}
> +
> +static int tegra_nand_write_page_hwecc(struct mtd_info *mtd,
> +				       struct nand_chip *chip,
> +				       const uint8_t *buf, int
> oob_required,
> +				       int page)
> +{
> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip-
> >controller);
> +	int ret;
> +
> +	tegra_nand_hw_ecc(ctrl, chip, true);
> +	ret = tegra_nand_page_xfer(mtd, chip, (void *)buf,
> oob_required, page,
> +				   false);
> +	tegra_nand_hw_ecc(ctrl, chip, false);
> +
> +	return ret;
> +}
> +
> +static void tegra_nand_setup_timing(struct tegra_nand_controller
> *ctrl,
> +				    const struct nand_sdr_timings
> *timings)
> +{
> +	/*
> +	 * The period (and all other timings in this function) is in
> ps,
> +	 * so need to take care here to avoid integer overflows.
> +	 */
> +	unsigned int rate = clk_get_rate(ctrl->clk) / 1000000;
> +	unsigned int period = DIV_ROUND_UP(1000000, rate);
> +	u32 val, reg = 0;
> +
> +	val = DIV_ROUND_UP(max3(timings->tAR_min, timings->tRR_min,
> +				timings->tRC_min), period);
> +	reg |= TIMING_TCR_TAR_TRR(OFFSET(val, 3));
> +
> +	val = DIV_ROUND_UP(max(max(timings->tCS_min, timings-
> >tCH_min),
> +			       max(timings->tALS_min, timings-
> >tALH_min)),
> +			   period);
> +	reg |= TIMING_TCS(OFFSET(val, 2));
> +
> +	val = DIV_ROUND_UP(max(timings->tRP_min, timings->tREA_max)
> + 6000,
> +			   period);
> +	reg |= TIMING_TRP(OFFSET(val, 1)) |
> TIMING_TRP_RESP(OFFSET(val, 1));
> +
> +	reg |= TIMING_TWB(OFFSET(DIV_ROUND_UP(timings->tWB_max,
> period), 1));
> +	reg |= TIMING_TWHR(OFFSET(DIV_ROUND_UP(timings->tWHR_min,
> period), 1));
> +	reg |= TIMING_TWH(OFFSET(DIV_ROUND_UP(timings->tWH_min,
> period), 1));
> +	reg |= TIMING_TWP(OFFSET(DIV_ROUND_UP(timings->tWP_min,
> period), 1));
> +	reg |= TIMING_TRH(OFFSET(DIV_ROUND_UP(timings->tREH_min,
> period), 1));
> +
> +	writel_relaxed(reg, ctrl->regs + TIMING_1);
> +
> +	val = DIV_ROUND_UP(timings->tADL_min, period);
> +	reg = TIMING_TADL(OFFSET(val, 3));
> +
> +	writel_relaxed(reg, ctrl->regs + TIMING_2);
> +}
> +
> +static int tegra_nand_setup_data_interface(struct mtd_info *mtd, int
> csline,
> +					   const struct
> nand_data_interface *conf)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip-
> >controller);
> +	const struct nand_sdr_timings *timings;
> +
> +	timings = nand_get_sdr_timings(conf);
> +	if (IS_ERR(timings))
> +		return PTR_ERR(timings);
> +
> +	if (csline == NAND_DATA_IFACE_CHECK_ONLY)
> +		return 0;
> +
> +	tegra_nand_setup_timing(ctrl, timings);
> +
> +	return 0;
> +}
> +
> +
> +const int rs_strength_bootable[] = { 4 };
> +const int rs_strength[] = { 4, 6, 8 };
> +const int bch_strength_bootable[] = { 8, 16 };
> +const int bch_strength[] = { 4, 8, 14, 16 };
> +
> +static int tegra_nand_get_strength(struct nand_chip *chip, const int
> *strength,
> +				   int strength_len, int oobsize)
> +{
> +	bool maximize = chip->ecc.options & NAND_ECC_MAXIMIZE;
> +	int i;
> +
> +	/*
> +	 * Loop through available strengths. Backwards in case we
> try to
> +	 * maximize the BCH strength.
> +	 */
> +	for (i = 0; i < strength_len; i++) {
> +		int strength_sel, bytes_per_step, bytes_per_page;
> +
> +		if (maximize) {
> +			strength_sel = strength[strength_len - i -
> 1];
> +		} else {
> +			strength_sel = strength[i];
> +
> +			if (strength_sel < chip->ecc_strength_ds)
> +				continue;
> +		}
> +
> +		bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH *
> strength_sel,
> +					      BITS_PER_BYTE);
> +		bytes_per_page = round_up(bytes_per_step * chip-
> >ecc.steps, 4);
> +
> +		/* Check whether strength fits OOB */
> +		if (bytes_per_page < (oobsize - SKIP_SPARE_BYTES))
> +			return strength_sel;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int tegra_nand_select_strength(struct nand_chip *chip, int
> oobsize)
> +{
> +	const int *strength;
> +	int strength_len;
> +
> +	switch (chip->ecc.algo) {
> +	case NAND_ECC_RS:
> +		if (chip->options & NAND_IS_BOOT_MEDIUM) {
> +			strength = rs_strength_bootable;
> +			strength_len =
> ARRAY_SIZE(rs_strength_bootable);
> +		} else {
> +			strength = rs_strength;
> +			strength_len = ARRAY_SIZE(rs_strength);
> +		}
> +		break;
> +	case NAND_ECC_BCH:
> +		if (chip->options & NAND_IS_BOOT_MEDIUM) {
> +			strength = bch_strength_bootable;
> +			strength_len =
> ARRAY_SIZE(bch_strength_bootable);
> +		} else {
> +			strength = bch_strength;
> +			strength_len = ARRAY_SIZE(bch_strength);
> +		}
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return tegra_nand_get_strength(chip, strength, strength_len,
> oobsize);
> +}
> +
> +static int tegra_nand_chips_init(struct device *dev,
> +				 struct tegra_nand_controller *ctrl)
> +{
> +	struct device_node *np = dev->of_node;
> +	struct device_node *np_nand;
> +	int nchips = of_get_child_count(np);
> +	struct tegra_nand_chip *nand;
> +	struct mtd_info *mtd;
> +	struct nand_chip *chip;
> +	unsigned long config, bch_config = 0;
> +	int bits_per_step;
> +	int ret;
> +
> +	if (nchips != 1) {
> +		dev_err(dev, "Currently only one NAND chip
> supported\n");
> +		return -EINVAL;
> +	}
> +
> +	np_nand = of_get_next_child(np, NULL);
> +
> +	nand = devm_kzalloc(dev, sizeof(*nand), GFP_KERNEL);
> +	if (!nand)
> +		return -ENOMEM;
> +
> +	nand->wp_gpio = devm_gpiod_get_optional(dev, "wp",
> GPIOD_OUT_LOW);
> +
> +	if (IS_ERR(nand->wp_gpio)) {
> +		ret = PTR_ERR(nand->wp_gpio);
> +		dev_err(dev, "Failed to request WP GPIO: %d\n",
> ret);
> +		return ret;
> +	}
> +
> +	chip = &nand->chip;
> +	chip->controller = &ctrl->controller;
> +
> +	mtd = nand_to_mtd(chip);
> +
> +	mtd->dev.parent = dev;
> +	if (!mtd->name)
> +		mtd->name = "tegra_nand";
> +	mtd->owner = THIS_MODULE;
> +
> +	nand_set_flash_node(chip, np_nand);

Hi,
i just tried this driver and it works great so far, thanks.
I just found, that assigning the of node after setting the mtd->name
makes it impossible to assign a name via devicetree label. I have read
the discussion about the label on this list, so I'm curious if this is
intentional? Setting mtd->name after nand_set_flash_node() enables the
label parameter.

> +
> +	chip->options = NAND_NO_SUBPAGE_WRITE |
> NAND_USE_BOUNCE_BUFFER;
> +	chip->exec_op = tegra_nand_exec_op;
> +	chip->select_chip = tegra_nand_select_chip;
> +	chip->setup_data_interface =
> tegra_nand_setup_data_interface;
> +
> +	ret = nand_scan_ident(mtd, 1, NULL);
> +	if (ret)
> +		return ret;
> +
> +	if (chip->bbt_options & NAND_BBT_USE_FLASH)
> +		chip->bbt_options |= NAND_BBT_NO_OOB;
> +
> +	chip->ecc.mode = NAND_ECC_HW;
> +	chip->ecc.size = 512;
> +	chip->ecc.steps = mtd->writesize / chip->ecc.size;
> +	if (chip->ecc_step_ds != 512) {
> +		dev_err(dev, "Unsupported step size %d\n", chip-
> >ecc_step_ds);
> +		return -EINVAL;
> +	}
> +
> +	chip->ecc.read_page = tegra_nand_read_page_hwecc;
> +	chip->ecc.write_page = tegra_nand_write_page_hwecc;
> +
> +	config = readl_relaxed(ctrl->regs + CFG);
> +	config |= CFG_PIPE_EN | CFG_SKIP_SPARE |
> CFG_SKIP_SPARE_SIZE_4;
> +
> +	if (chip->options & NAND_BUSWIDTH_16)
> +		config |= CFG_BUS_WIDTH_16;
> +
> +	if (chip->ecc.algo == NAND_ECC_UNKNOWN) {
> +		if (mtd->writesize < 2048)
> +			chip->ecc.algo = NAND_ECC_RS;
> +		else
> +			chip->ecc.algo = NAND_ECC_BCH;
> +	}
> +
> +	if (chip->ecc.algo == NAND_ECC_BCH && mtd->writesize < 2048)
> {
> +		dev_err(dev, "BCH supportes 2K or 4K page size
> only\n");
> +		return -EINVAL;
> +	}
> +
> +	if (!chip->ecc.strength) {
> +		ret = tegra_nand_select_strength(chip, mtd-
> >oobsize);
> +		if (ret < 0) {
> +			dev_err(dev, "No valid strenght found,
> minimum %d\n",
> +				chip->ecc_strength_ds);
> +			return ret;
> +		}
> +
> +		chip->ecc.strength = ret;
> +	}
> +
> +	switch (chip->ecc.algo) {
> +	case NAND_ECC_RS:
> +		bits_per_step = BITS_PER_STEP_RS * chip-
> >ecc.strength;
> +		mtd_set_ooblayout(mtd, &tegra_nand_oob_rs_ops);
> +		switch (chip->ecc.strength) {
> +		case 4:
> +			config |= CFG_ECC_SEL | CFG_TVAL_4;
> +			break;
> +		case 6:
> +			config |= CFG_ECC_SEL | CFG_TVAL_6;
> +			break;
> +		case 8:
> +			config |= CFG_ECC_SEL | CFG_TVAL_8;
> +			break;
> +		default:
> +			dev_err(dev, "ECC strength %d not
> supported\n",
> +				chip->ecc.strength);
> +			return -EINVAL;
> +		}
> +		break;
> +	case NAND_ECC_BCH:
> +		bits_per_step = BITS_PER_STEP_BCH * chip-
> >ecc.strength;
> +		mtd_set_ooblayout(mtd, &tegra_nand_oob_bch_ops);
> +		switch (chip->ecc.strength) {
> +		case 4:
> +			bch_config = BCH_TVAL_4;
> +			break;
> +		case 8:
> +			bch_config = BCH_TVAL_8;
> +			break;
> +		case 14:
> +			bch_config = BCH_TVAL_14;
> +			break;
> +		case 16:
> +			bch_config = BCH_TVAL_16;
> +			break;
> +		default:
> +			dev_err(dev, "ECC strength %d not
> supported\n",
> +				chip->ecc.strength);
> +			return -EINVAL;
> +		}
> +		break;
> +	default:
> +		dev_err(dev, "ECC algorithm not supported\n");
> +		return -EINVAL;
> +	}
> +
> +	dev_info(dev, "Using %s with strength %d per 512 byte
> step\n",
> +			chip->ecc.algo == NAND_ECC_BCH ? "BCH" :
> "RS",
> +			chip->ecc.strength);
> +
> +	chip->ecc.bytes = DIV_ROUND_UP(bits_per_step,
> BITS_PER_BYTE);
> +
> +	switch (mtd->writesize) {
> +	case 256:
> +		config |= CFG_PS_256;
> +		break;
> +	case 512:
> +		config |= CFG_PS_512;
> +		break;
> +	case 1024:
> +		config |= CFG_PS_1024;
> +		break;
> +	case 2048:
> +		config |= CFG_PS_2048;
> +		break;
> +	case 4096:
> +		config |= CFG_PS_4096;
> +		break;
> +	default:
> +		dev_err(dev, "Unsupported writesize %d\n", mtd-
> >writesize);
> +		return -ENODEV;
> +	}
> +
> +	writel_relaxed(config, ctrl->regs + CFG);
> +	writel_relaxed(bch_config, ctrl->regs + BCH_CONFIG);
> +
> +	ret = nand_scan_tail(mtd);
> +	if (ret)
> +		return ret;
> +
> +	mtd_ooblayout_free(mtd, 0, &nand->tag);
> +
> +	config |= CFG_TAG_BYTE_SIZE(nand->tag.length - 1);
> +	writel_relaxed(config, ctrl->regs + CFG);
> +
> +	ret = mtd_device_register(mtd, NULL, 0);
> +	if (ret) {
> +		dev_err(dev, "Failed to register mtd device: %d\n",
> ret);
> +		nand_cleanup(chip);
> +		return ret;
> +	}
> +
> +	ctrl->chip = chip;
> +
> +	return 0;
> +}
> +
> +static int tegra_nand_probe(struct platform_device *pdev)
> +{
> +	struct reset_control *rst;
> +	struct tegra_nand_controller *ctrl;
> +	struct resource *res;
> +	unsigned long reg;
> +	int irq, err = 0;
> +
> +	ctrl = devm_kzalloc(&pdev->dev, sizeof(*ctrl), GFP_KERNEL);
> +	if (!ctrl)
> +		return -ENOMEM;
> +
> +	ctrl->dev = &pdev->dev;
> +	nand_hw_control_init(&ctrl->controller);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	ctrl->regs = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(ctrl->regs))
> +		return PTR_ERR(ctrl->regs);
> +
> +	rst = devm_reset_control_get(&pdev->dev, "nand");
> +	if (IS_ERR(rst))
> +		return PTR_ERR(rst);
> +
> +	ctrl->clk = devm_clk_get(&pdev->dev, "nand");
> +	if (IS_ERR(ctrl->clk))
> +		return PTR_ERR(ctrl->clk);
> +
> +	err = clk_prepare_enable(ctrl->clk);
> +	if (err)
> +		return err;
> +
> +	err = reset_control_reset(rst);
> +	if (err)
> +		goto err_disable_clk;
> +
> +	reg = HWSTATUS_RDSTATUS_MASK(1) | HWSTATUS_RDSTATUS_VALUE(0)
> |
> +		HWSTATUS_RBSY_MASK(NAND_STATUS_READY) |
> +		HWSTATUS_RBSY_VALUE(NAND_STATUS_READY);
> +	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
> +	writel_relaxed(reg, ctrl->regs + HWSTATUS_MASK);
> +
> +	init_completion(&ctrl->command_complete);
> +	init_completion(&ctrl->dma_complete);
> +
> +	/* clear interrupts */
> +	reg = readl_relaxed(ctrl->regs + ISR);
> +	writel_relaxed(reg, ctrl->regs + ISR);
> +
> +	irq = platform_get_irq(pdev, 0);
> +	err = devm_request_irq(&pdev->dev, irq, tegra_nand_irq, 0,
> +			       dev_name(&pdev->dev), ctrl);
> +	if (err)
> +		goto err_disable_clk;
> +
> +	writel_relaxed(DMA_CTRL_IS_DONE, ctrl->regs + DMA_CTRL);
> +
> +	/* enable interrupts */
> +	reg = IER_UND | IER_OVR | IER_CMD_DONE | IER_GIE;
> +	writel_relaxed(reg, ctrl->regs + IER);
> +
> +	/* reset config */
> +	writel_relaxed(0, ctrl->regs + CFG);
> +
> +	err = tegra_nand_chips_init(ctrl->dev, ctrl);
> +	if (err)
> +		goto err_disable_clk;
> +
> +	platform_set_drvdata(pdev, ctrl);
> +
> +	return 0;
> +
> +err_disable_clk:
> +	clk_disable_unprepare(ctrl->clk);
> +	return err;
> +}
> +
> +static int tegra_nand_remove(struct platform_device *pdev)
> +{
> +	struct tegra_nand_controller *ctrl =
> platform_get_drvdata(pdev);
> +
> +	nand_release(nand_to_mtd(ctrl->chip));
> +
> +	clk_disable_unprepare(ctrl->clk);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id tegra_nand_of_match[] = {
> +	{ .compatible = "nvidia,tegra20-nand" },
> +	{ /* sentinel */ }
> +};
> +
> +static struct platform_driver tegra_nand_driver = {
> +	.driver = {
> +		.name = "tegra-nand",
> +		.of_match_table = tegra_nand_of_match,
> +	},
> +	.probe = tegra_nand_probe,
> +	.remove = tegra_nand_remove,
> +};
> +module_platform_driver(tegra_nand_driver);
> +
> +MODULE_DESCRIPTION("NVIDIA Tegra NAND driver");
> +MODULE_AUTHOR("Thierry Reding <thierry.reding@nvidia.com>");
> +MODULE_AUTHOR("Lucas Stach <dev@lynxeye.de>");
> +MODULE_AUTHOR("Stefan Agner <stefan@agner.ch>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_DEVICE_TABLE(of, tegra_nand_of_match);

Sorry for any noise/mistake, I'm new to kernel development
Greetings
Randolph Maaßen
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Hi Randolph,

On 04.06.2018 19:16, Randolph Maaßen wrote:
> Am Freitag, den 01.06.2018, 00:16 +0200 schrieb Stefan Agner:
>> Add support for the NAND flash controller found on NVIDIA
>> Tegra 2 SoCs. This implementation does not make use of the
>> command queue feature. Regular operations/data transfers are
>> done in PIO mode. Page read/writes with hardware ECC make
>> use of the DMA for data transfer.
>>
>> Signed-off-by: Lucas Stach <dev@lynxeye.de>
>> Signed-off-by: Stefan Agner <stefan@agner.ch>
>> ---
>>  MAINTAINERS                       |    7 +
>>  drivers/mtd/nand/raw/Kconfig      |    6 +
>>  drivers/mtd/nand/raw/Makefile     |    1 +
>>  drivers/mtd/nand/raw/tegra_nand.c | 1143
>> +++++++++++++++++++++++++++++
>>  4 files changed, 1157 insertions(+)
>>  create mode 100644 drivers/mtd/nand/raw/tegra_nand.c
>>
[...]
>> +static int tegra_nand_chips_init(struct device *dev,
>> +				 struct tegra_nand_controller *ctrl)
>> +{
>> +	struct device_node *np = dev->of_node;
>> +	struct device_node *np_nand;
>> +	int nchips = of_get_child_count(np);
>> +	struct tegra_nand_chip *nand;
>> +	struct mtd_info *mtd;
>> +	struct nand_chip *chip;
>> +	unsigned long config, bch_config = 0;
>> +	int bits_per_step;
>> +	int ret;
>> +
>> +	if (nchips != 1) {
>> +		dev_err(dev, "Currently only one NAND chip
>> supported\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	np_nand = of_get_next_child(np, NULL);
>> +
>> +	nand = devm_kzalloc(dev, sizeof(*nand), GFP_KERNEL);
>> +	if (!nand)
>> +		return -ENOMEM;
>> +
>> +	nand->wp_gpio = devm_gpiod_get_optional(dev, "wp",
>> GPIOD_OUT_LOW);
>> +
>> +	if (IS_ERR(nand->wp_gpio)) {
>> +		ret = PTR_ERR(nand->wp_gpio);
>> +		dev_err(dev, "Failed to request WP GPIO: %d\n",
>> ret);
>> +		return ret;
>> +	}
>> +
>> +	chip = &nand->chip;
>> +	chip->controller = &ctrl->controller;
>> +
>> +	mtd = nand_to_mtd(chip);
>> +
>> +	mtd->dev.parent = dev;
>> +	if (!mtd->name)
>> +		mtd->name = "tegra_nand";
>> +	mtd->owner = THIS_MODULE;
>> +
>> +	nand_set_flash_node(chip, np_nand);
> 
> Hi,
> i just tried this driver and it works great so far, thanks.
> I just found, that assigning the of node after setting the mtd->name
> makes it impossible to assign a name via devicetree label. I have read
> the discussion about the label on this list, so I'm curious if this is
> intentional? Setting mtd->name after nand_set_flash_node() enables the
> label parameter.
> 

Hm, good catch. No that was not intentional. The name indeed should be
assigned after the call to nand_set_flash_node. Will fix this in the
next revision.

>> +
>> +	chip->options = NAND_NO_SUBPAGE_WRITE |
>> NAND_USE_BOUNCE_BUFFER;
>> +	chip->exec_op = tegra_nand_exec_op;
>> +	chip->select_chip = tegra_nand_select_chip;
>> +	chip->setup_data_interface =
>> tegra_nand_setup_data_interface;
>> +
>> +	ret = nand_scan_ident(mtd, 1, NULL);
>> +	if (ret)
>> +		return ret;
>> +
>> +	if (chip->bbt_options & NAND_BBT_USE_FLASH)
>> +		chip->bbt_options |= NAND_BBT_NO_OOB;
>> +
>> +	chip->ecc.mode = NAND_ECC_HW;
>> +	chip->ecc.size = 512;
>> +	chip->ecc.steps = mtd->writesize / chip->ecc.size;
>> +	if (chip->ecc_step_ds != 512) {
>> +		dev_err(dev, "Unsupported step size %d\n", chip-
>> >ecc_step_ds);
>> +		return -EINVAL;
>> +	}
>> +
>> +	chip->ecc.read_page = tegra_nand_read_page_hwecc;
>> +	chip->ecc.write_page = tegra_nand_write_page_hwecc;
>> +
>> +	config = readl_relaxed(ctrl->regs + CFG);
>> +	config |= CFG_PIPE_EN | CFG_SKIP_SPARE |
>> CFG_SKIP_SPARE_SIZE_4;
>> +
>> +	if (chip->options & NAND_BUSWIDTH_16)
>> +		config |= CFG_BUS_WIDTH_16;
>> +
>> +	if (chip->ecc.algo == NAND_ECC_UNKNOWN) {
>> +		if (mtd->writesize < 2048)
>> +			chip->ecc.algo = NAND_ECC_RS;
>> +		else
>> +			chip->ecc.algo = NAND_ECC_BCH;
>> +	}
>> +
>> +	if (chip->ecc.algo == NAND_ECC_BCH && mtd->writesize < 2048)
>> {
>> +		dev_err(dev, "BCH supportes 2K or 4K page size
>> only\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (!chip->ecc.strength) {
>> +		ret = tegra_nand_select_strength(chip, mtd-
>> >oobsize);
>> +		if (ret < 0) {
>> +			dev_err(dev, "No valid strenght found,
>> minimum %d\n",
>> +				chip->ecc_strength_ds);
>> +			return ret;
>> +		}
>> +
>> +		chip->ecc.strength = ret;
>> +	}
>> +
>> +	switch (chip->ecc.algo) {
>> +	case NAND_ECC_RS:
>> +		bits_per_step = BITS_PER_STEP_RS * chip-
>> >ecc.strength;
>> +		mtd_set_ooblayout(mtd, &tegra_nand_oob_rs_ops);
>> +		switch (chip->ecc.strength) {
>> +		case 4:
>> +			config |= CFG_ECC_SEL | CFG_TVAL_4;
>> +			break;
>> +		case 6:
>> +			config |= CFG_ECC_SEL | CFG_TVAL_6;
>> +			break;
>> +		case 8:
>> +			config |= CFG_ECC_SEL | CFG_TVAL_8;
>> +			break;
>> +		default:
>> +			dev_err(dev, "ECC strength %d not
>> supported\n",
>> +				chip->ecc.strength);
>> +			return -EINVAL;
>> +		}
>> +		break;
>> +	case NAND_ECC_BCH:
>> +		bits_per_step = BITS_PER_STEP_BCH * chip-
>> >ecc.strength;
>> +		mtd_set_ooblayout(mtd, &tegra_nand_oob_bch_ops);
>> +		switch (chip->ecc.strength) {
>> +		case 4:
>> +			bch_config = BCH_TVAL_4;
>> +			break;
>> +		case 8:
>> +			bch_config = BCH_TVAL_8;
>> +			break;
>> +		case 14:
>> +			bch_config = BCH_TVAL_14;
>> +			break;
>> +		case 16:
>> +			bch_config = BCH_TVAL_16;
>> +			break;
>> +		default:
>> +			dev_err(dev, "ECC strength %d not
>> supported\n",
>> +				chip->ecc.strength);
>> +			return -EINVAL;
>> +		}
>> +		break;
>> +	default:
>> +		dev_err(dev, "ECC algorithm not supported\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	dev_info(dev, "Using %s with strength %d per 512 byte
>> step\n",
>> +			chip->ecc.algo == NAND_ECC_BCH ? "BCH" :
>> "RS",
>> +			chip->ecc.strength);
>> +
>> +	chip->ecc.bytes = DIV_ROUND_UP(bits_per_step,
>> BITS_PER_BYTE);
>> +
>> +	switch (mtd->writesize) {
>> +	case 256:
>> +		config |= CFG_PS_256;
>> +		break;
>> +	case 512:
>> +		config |= CFG_PS_512;
>> +		break;
>> +	case 1024:
>> +		config |= CFG_PS_1024;
>> +		break;
>> +	case 2048:
>> +		config |= CFG_PS_2048;
>> +		break;
>> +	case 4096:
>> +		config |= CFG_PS_4096;
>> +		break;
>> +	default:
>> +		dev_err(dev, "Unsupported writesize %d\n", mtd-
>> >writesize);
>> +		return -ENODEV;
>> +	}
>> +
>> +	writel_relaxed(config, ctrl->regs + CFG);
>> +	writel_relaxed(bch_config, ctrl->regs + BCH_CONFIG);
>> +
>> +	ret = nand_scan_tail(mtd);
>> +	if (ret)
>> +		return ret;
>> +
>> +	mtd_ooblayout_free(mtd, 0, &nand->tag);
>> +
>> +	config |= CFG_TAG_BYTE_SIZE(nand->tag.length - 1);
>> +	writel_relaxed(config, ctrl->regs + CFG);
>> +
>> +	ret = mtd_device_register(mtd, NULL, 0);
>> +	if (ret) {
>> +		dev_err(dev, "Failed to register mtd device: %d\n",
>> ret);
>> +		nand_cleanup(chip);
>> +		return ret;
>> +	}
>> +
>> +	ctrl->chip = chip;
>> +
>> +	return 0;
>> +}
>> +
>> +static int tegra_nand_probe(struct platform_device *pdev)
>> +{
>> +	struct reset_control *rst;
>> +	struct tegra_nand_controller *ctrl;
>> +	struct resource *res;
>> +	unsigned long reg;
>> +	int irq, err = 0;
>> +
>> +	ctrl = devm_kzalloc(&pdev->dev, sizeof(*ctrl), GFP_KERNEL);
>> +	if (!ctrl)
>> +		return -ENOMEM;
>> +
>> +	ctrl->dev = &pdev->dev;
>> +	nand_hw_control_init(&ctrl->controller);
>> +
>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	ctrl->regs = devm_ioremap_resource(&pdev->dev, res);
>> +	if (IS_ERR(ctrl->regs))
>> +		return PTR_ERR(ctrl->regs);
>> +
>> +	rst = devm_reset_control_get(&pdev->dev, "nand");
>> +	if (IS_ERR(rst))
>> +		return PTR_ERR(rst);
>> +
>> +	ctrl->clk = devm_clk_get(&pdev->dev, "nand");
>> +	if (IS_ERR(ctrl->clk))
>> +		return PTR_ERR(ctrl->clk);
>> +
>> +	err = clk_prepare_enable(ctrl->clk);
>> +	if (err)
>> +		return err;
>> +
>> +	err = reset_control_reset(rst);
>> +	if (err)
>> +		goto err_disable_clk;
>> +
>> +	reg = HWSTATUS_RDSTATUS_MASK(1) | HWSTATUS_RDSTATUS_VALUE(0)
>> |
>> +		HWSTATUS_RBSY_MASK(NAND_STATUS_READY) |
>> +		HWSTATUS_RBSY_VALUE(NAND_STATUS_READY);
>> +	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
>> +	writel_relaxed(reg, ctrl->regs + HWSTATUS_MASK);
>> +
>> +	init_completion(&ctrl->command_complete);
>> +	init_completion(&ctrl->dma_complete);
>> +
>> +	/* clear interrupts */
>> +	reg = readl_relaxed(ctrl->regs + ISR);
>> +	writel_relaxed(reg, ctrl->regs + ISR);
>> +
>> +	irq = platform_get_irq(pdev, 0);
>> +	err = devm_request_irq(&pdev->dev, irq, tegra_nand_irq, 0,
>> +			       dev_name(&pdev->dev), ctrl);
>> +	if (err)
>> +		goto err_disable_clk;
>> +
>> +	writel_relaxed(DMA_CTRL_IS_DONE, ctrl->regs + DMA_CTRL);
>> +
>> +	/* enable interrupts */
>> +	reg = IER_UND | IER_OVR | IER_CMD_DONE | IER_GIE;
>> +	writel_relaxed(reg, ctrl->regs + IER);
>> +
>> +	/* reset config */
>> +	writel_relaxed(0, ctrl->regs + CFG);
>> +
>> +	err = tegra_nand_chips_init(ctrl->dev, ctrl);
>> +	if (err)
>> +		goto err_disable_clk;
>> +
>> +	platform_set_drvdata(pdev, ctrl);
>> +
>> +	return 0;
>> +
>> +err_disable_clk:
>> +	clk_disable_unprepare(ctrl->clk);
>> +	return err;
>> +}
>> +
>> +static int tegra_nand_remove(struct platform_device *pdev)
>> +{
>> +	struct tegra_nand_controller *ctrl =
>> platform_get_drvdata(pdev);
>> +
>> +	nand_release(nand_to_mtd(ctrl->chip));
>> +
>> +	clk_disable_unprepare(ctrl->clk);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id tegra_nand_of_match[] = {
>> +	{ .compatible = "nvidia,tegra20-nand" },
>> +	{ /* sentinel */ }
>> +};
>> +
>> +static struct platform_driver tegra_nand_driver = {
>> +	.driver = {
>> +		.name = "tegra-nand",
>> +		.of_match_table = tegra_nand_of_match,
>> +	},
>> +	.probe = tegra_nand_probe,
>> +	.remove = tegra_nand_remove,
>> +};
>> +module_platform_driver(tegra_nand_driver);
>> +
>> +MODULE_DESCRIPTION("NVIDIA Tegra NAND driver");
>> +MODULE_AUTHOR("Thierry Reding <thierry.reding@nvidia.com>");
>> +MODULE_AUTHOR("Lucas Stach <dev@lynxeye.de>");
>> +MODULE_AUTHOR("Stefan Agner <stefan@agner.ch>");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_DEVICE_TABLE(of, tegra_nand_of_match);
> 
> Sorry for any noise/mistake, I'm new to kernel development

That was constructive feedback! Thanks for pointing out!

--
Stefan
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On 01.06.2018 11:20, Dmitry Osipenko wrote:
> On 01.06.2018 01:16, Stefan Agner wrote:
>> Add support for the NAND flash controller found on NVIDIA
>> Tegra 2 SoCs. This implementation does not make use of the
>> command queue feature. Regular operations/data transfers are
>> done in PIO mode. Page read/writes with hardware ECC make
>> use of the DMA for data transfer.
>>
>> Signed-off-by: Lucas Stach <dev@lynxeye.de>
>> Signed-off-by: Stefan Agner <stefan@agner.ch>
>> ---
>>  MAINTAINERS                       |    7 +
>>  drivers/mtd/nand/raw/Kconfig      |    6 +
>>  drivers/mtd/nand/raw/Makefile     |    1 +
>>  drivers/mtd/nand/raw/tegra_nand.c | 1143 +++++++++++++++++++++++++++++
>>  4 files changed, 1157 insertions(+)
>>  create mode 100644 drivers/mtd/nand/raw/tegra_nand.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 58b9861ccf99..c2e5571c85d4 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -13844,6 +13844,13 @@ M:	Laxman Dewangan <ldewangan@nvidia.com>
>>  S:	Supported
>>  F:	drivers/input/keyboard/tegra-kbc.c
>>
>> +TEGRA NAND DRIVER
>> +M:	Stefan Agner <stefan@agner.ch>
>> +M:	Lucas Stach <dev@lynxeye.de>
>> +S:	Maintained
>> +F:	Documentation/devicetree/bindings/mtd/nvidia-tegra20-nand.txt
>> +F:	drivers/mtd/nand/raw/tegra_nand.c
>> +
>>  TEGRA PWM DRIVER
>>  M:	Thierry Reding <thierry.reding@gmail.com>
>>  S:	Supported
>> diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
>> index 19a2b283fbbe..e9093f52371e 100644
>> --- a/drivers/mtd/nand/raw/Kconfig
>> +++ b/drivers/mtd/nand/raw/Kconfig
>> @@ -534,4 +534,10 @@ config MTD_NAND_MTK
>>  	  Enables support for NAND controller on MTK SoCs.
>>  	  This controller is found on mt27xx, mt81xx, mt65xx SoCs.
>>
>> +config MTD_NAND_TEGRA
>> +	tristate "Support for NAND controller on NVIDIA Tegra"
>> +	depends on ARCH_TEGRA || COMPILE_TEST
>> +	help
>> +	  Enables support for NAND flash controller on NVIDIA Tegra SoC.
>> +
>>  endif # MTD_NAND
>> diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile
>> index 165b7ef9e9a1..d5a5f9832b88 100644
>> --- a/drivers/mtd/nand/raw/Makefile
>> +++ b/drivers/mtd/nand/raw/Makefile
>> @@ -56,6 +56,7 @@ obj-$(CONFIG_MTD_NAND_HISI504)	        += hisi504_nand.o
>>  obj-$(CONFIG_MTD_NAND_BRCMNAND)		+= brcmnand/
>>  obj-$(CONFIG_MTD_NAND_QCOM)		+= qcom_nandc.o
>>  obj-$(CONFIG_MTD_NAND_MTK)		+= mtk_ecc.o mtk_nand.o
>> +obj-$(CONFIG_MTD_NAND_TEGRA)		+= tegra_nand.o
>>
>>  nand-objs := nand_base.o nand_bbt.o nand_timings.o nand_ids.o
>>  nand-objs += nand_amd.o
>> diff --git a/drivers/mtd/nand/raw/tegra_nand.c b/drivers/mtd/nand/raw/tegra_nand.c
>> new file mode 100644
>> index 000000000000..e9664f2938a3
>> --- /dev/null
>> +++ b/drivers/mtd/nand/raw/tegra_nand.c
>> @@ -0,0 +1,1143 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (C) 2018 Stefan Agner <stefan@agner.ch>
>> + * Copyright (C) 2014-2015 Lucas Stach <dev@lynxeye.de>
>> + * Copyright (C) 2012 Avionic Design GmbH
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/completion.h>
>> +#include <linux/delay.h>
>> +#include <linux/dma-mapping.h>
>> +#include <linux/err.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/io.h>
>> +#include <linux/module.h>
>> +#include <linux/mtd/partitions.h>
>> +#include <linux/mtd/rawnand.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/reset.h>
>> +
>> +#define CMD					0x00
>> +#define   CMD_GO				BIT(31)
>> +#define   CMD_CLE				BIT(30)
>> +#define   CMD_ALE				BIT(29)
>> +#define   CMD_PIO				BIT(28)
>> +#define   CMD_TX				BIT(27)
>> +#define   CMD_RX				BIT(26)
>> +#define   CMD_SEC_CMD				BIT(25)
>> +#define   CMD_AFT_DAT				BIT(24)
>> +#define   CMD_TRANS_SIZE(x)			(((x - 1) & 0xf) << 20)
>> +#define   CMD_A_VALID				BIT(19)
>> +#define   CMD_B_VALID				BIT(18)
>> +#define   CMD_RD_STATUS_CHK			BIT(17)
>> +#define   CMD_RBSY_CHK				BIT(16)
>> +#define   CMD_CE(x)				BIT((8 + ((x) & 0x7)))
>> +#define   CMD_CLE_SIZE(x)			(((x - 1) & 0x3) << 4)
>> +#define   CMD_ALE_SIZE(x)			(((x - 1) & 0xf) << 0)
>> +
>> +#define STATUS					0x04
>> +
>> +#define ISR					0x08
>> +#define   ISR_CORRFAIL_ERR			BIT(24)
>> +#define   ISR_UND				BIT(7)
>> +#define   ISR_OVR				BIT(6)
>> +#define   ISR_CMD_DONE				BIT(5)
>> +#define   ISR_ECC_ERR				BIT(4)
>> +
>> +#define IER					0x0c
>> +#define   IER_ERR_TRIG_VAL(x)			(((x) & 0xf) << 16)
>> +#define   IER_UND				BIT(7)
>> +#define   IER_OVR				BIT(6)
>> +#define   IER_CMD_DONE				BIT(5)
>> +#define   IER_ECC_ERR				BIT(4)
>> +#define   IER_GIE				BIT(0)
>> +
>> +#define CFG					0x10
>> +#define   CFG_HW_ECC				BIT(31)
>> +#define   CFG_ECC_SEL				BIT(30)
>> +#define   CFG_ERR_COR				BIT(29)
>> +#define   CFG_PIPE_EN				BIT(28)
>> +#define   CFG_TVAL_4				(0 << 24)
>> +#define   CFG_TVAL_6				(1 << 24)
>> +#define   CFG_TVAL_8				(2 << 24)
>> +#define   CFG_SKIP_SPARE			BIT(23)
>> +#define   CFG_BUS_WIDTH_16			BIT(21)
>> +#define   CFG_COM_BSY				BIT(20)
>> +#define   CFG_PS_256				(0 << 16)
>> +#define   CFG_PS_512				(1 << 16)
>> +#define   CFG_PS_1024				(2 << 16)
>> +#define   CFG_PS_2048				(3 << 16)
>> +#define   CFG_PS_4096				(4 << 16)
>> +#define   CFG_SKIP_SPARE_SIZE_4			(0 << 14)
>> +#define   CFG_SKIP_SPARE_SIZE_8			(1 << 14)
>> +#define   CFG_SKIP_SPARE_SIZE_12		(2 << 14)
>> +#define   CFG_SKIP_SPARE_SIZE_16		(3 << 14)
>> +#define   CFG_TAG_BYTE_SIZE(x)			((x) & 0xff)
>> +
>> +#define TIMING_1				0x14
>> +#define   TIMING_TRP_RESP(x)			(((x) & 0xf) << 28)
>> +#define   TIMING_TWB(x)				(((x) & 0xf) << 24)
>> +#define   TIMING_TCR_TAR_TRR(x)			(((x) & 0xf) << 20)
>> +#define   TIMING_TWHR(x)			(((x) & 0xf) << 16)
>> +#define   TIMING_TCS(x)				(((x) & 0x3) << 14)
>> +#define   TIMING_TWH(x)				(((x) & 0x3) << 12)
>> +#define   TIMING_TWP(x)				(((x) & 0xf) <<  8)
>> +#define   TIMING_TRH(x)				(((x) & 0x3) <<  4)
>> +#define   TIMING_TRP(x)				(((x) & 0xf) <<  0)
>> +
>> +#define RESP					0x18
>> +
>> +#define TIMING_2				0x1c
>> +#define   TIMING_TADL(x)			((x) & 0xf)
>> +
>> +#define CMD_1					0x20
>> +#define CMD_2					0x24
>> +#define ADDR_1					0x28
>> +#define ADDR_2					0x2c
>> +
>> +#define DMA_CTRL				0x30
>> +#define   DMA_CTRL_GO				BIT(31)
>> +#define   DMA_CTRL_IN				(0 << 30)
>> +#define   DMA_CTRL_OUT				BIT(30)
>> +#define   DMA_CTRL_PERF_EN			BIT(29)
>> +#define   DMA_CTRL_IE_DONE			BIT(28)
>> +#define   DMA_CTRL_REUSE			BIT(27)
>> +#define   DMA_CTRL_BURST_1			(2 << 24)
>> +#define   DMA_CTRL_BURST_4			(3 << 24)
>> +#define   DMA_CTRL_BURST_8			(4 << 24)
>> +#define   DMA_CTRL_BURST_16			(5 << 24)
>> +#define   DMA_CTRL_IS_DONE			BIT(20)
>> +#define   DMA_CTRL_EN_A				BIT(2)
>> +#define   DMA_CTRL_EN_B				BIT(1)
>> +
>> +#define DMA_CFG_A				0x34
>> +#define DMA_CFG_B				0x38
>> +
>> +#define FIFO_CTRL				0x3c
>> +#define   FIFO_CTRL_CLR_ALL			BIT(3)
>> +
>> +#define DATA_PTR				0x40
>> +#define TAG_PTR					0x44
>> +#define ECC_PTR					0x48
>> +
>> +#define DEC_STATUS				0x4c
>> +#define   DEC_STATUS_A_ECC_FAIL			BIT(1)
>> +#define   DEC_STATUS_ERR_COUNT_MASK		0x00ff0000
>> +#define   DEC_STATUS_ERR_COUNT_SHIFT		16
>> +
>> +#define HWSTATUS_CMD				0x50
>> +#define HWSTATUS_MASK				0x54
>> +#define   HWSTATUS_RDSTATUS_MASK(x)		(((x) & 0xff) << 24)
>> +#define   HWSTATUS_RDSTATUS_VALUE(x)		(((x) & 0xff) << 16)
>> +#define   HWSTATUS_RBSY_MASK(x)			(((x) & 0xff) << 8)
>> +#define   HWSTATUS_RBSY_VALUE(x)		(((x) & 0xff) << 0)
>> +
>> +#define BCH_CONFIG				0xcc
>> +#define   BCH_ENABLE				BIT(0)
>> +#define   BCH_TVAL_4				(0 << 4)
>> +#define   BCH_TVAL_8				(1 << 4)
>> +#define   BCH_TVAL_14				(2 << 4)
>> +#define   BCH_TVAL_16				(3 << 4)
>> +
>> +#define DEC_STAT_RESULT				0xd0
>> +#define DEC_STAT_BUF				0xd4
>> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_MASK	0xff000000
>> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_SHIFT	24
>> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_MASK	0x00ff0000
>> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT	16
>> +#define   DEC_STAT_BUF_MAX_CORR_CNT_MASK	0x00001f00
>> +#define   DEC_STAT_BUF_MAX_CORR_CNT_SHIFT	8
>> +
>> +#define OFFSET(val, off)		((val) < (off) ? 0 : (val) - (off))
>> +
>> +#define SKIP_SPARE_BYTES	4
>> +#define BITS_PER_STEP_RS	18
>> +#define BITS_PER_STEP_BCH	13
>> +
>> +struct tegra_nand_controller {
>> +	struct nand_hw_control controller;
>> +	void __iomem *regs;
>> +	struct clk *clk;
>> +	struct device *dev;
>> +	struct completion command_complete;
>> +	struct completion dma_complete;
>> +	bool last_read_error;
>> +	int cur_chip;
>> +	struct nand_chip *chip;
>> +};
>> +
>> +struct tegra_nand_chip {
>> +	struct nand_chip chip;
>> +	struct gpio_desc *wp_gpio;
>> +	struct mtd_oob_region tag;
>> +};
>> +
>> +static inline struct tegra_nand_controller *to_tegra_ctrl(
>> +						struct nand_hw_control *hw_ctrl)
>> +{
>> +	return container_of(hw_ctrl, struct tegra_nand_controller, controller);
>> +}
>> +
>> +static inline struct tegra_nand_chip *to_tegra_chip(struct nand_chip *chip)
>> +{
>> +	return container_of(chip, struct tegra_nand_chip, chip);
>> +}
>> +
>> +static int tegra_nand_ooblayout_rs_ecc(struct mtd_info *mtd, int section,
>> +				       struct mtd_oob_region *oobregion)
>> +{
>> +	struct nand_chip *chip = mtd_to_nand(mtd);
>> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS * chip->ecc.strength,
>> +					  BITS_PER_BYTE);
>> +
>> +	if (section > 0)
>> +		return -ERANGE;
>> +
>> +	oobregion->offset = SKIP_SPARE_BYTES;
>> +	oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 4);
>> +
>> +	return 0;
>> +}
>> +
>> +static int tegra_nand_ooblayout_rs_free(struct mtd_info *mtd, int section,
>> +					struct mtd_oob_region *oobregion)
>> +{
>> +	struct nand_chip *chip = mtd_to_nand(mtd);
>> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS * chip->ecc.strength,
>> +					  BITS_PER_BYTE);
>> +
>> +	if (section > 0)
>> +		return -ERANGE;
>> +
>> +	oobregion->offset = SKIP_SPARE_BYTES +
>> +			    round_up(bytes_per_step * chip->ecc.steps, 4);
>> +	oobregion->length = mtd->oobsize - oobregion->offset;
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct mtd_ooblayout_ops tegra_nand_oob_rs_ops = {
>> +	.ecc = tegra_nand_ooblayout_rs_ecc,
>> +	.free = tegra_nand_ooblayout_rs_free,
>> +};
>> +
>> +static int tegra_nand_ooblayout_bch_ecc(struct mtd_info *mtd, int section,
>> +				       struct mtd_oob_region *oobregion)
>> +{
>> +	struct nand_chip *chip = mtd_to_nand(mtd);
>> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH * chip->ecc.strength,
>> +					  BITS_PER_BYTE);
>> +
>> +	if (section > 0)
>> +		return -ERANGE;
>> +
>> +	oobregion->offset = SKIP_SPARE_BYTES;
>> +	oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 4);
>> +
>> +	return 0;
>> +}
>> +
>> +static int tegra_nand_ooblayout_bch_free(struct mtd_info *mtd, int section,
>> +					struct mtd_oob_region *oobregion)
>> +{
>> +	struct nand_chip *chip = mtd_to_nand(mtd);
>> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH * chip->ecc.strength,
>> +					  BITS_PER_BYTE);
>> +
>> +	if (section > 0)
>> +		return -ERANGE;
>> +
>> +	oobregion->offset = SKIP_SPARE_BYTES +
>> +			    round_up(bytes_per_step * chip->ecc.steps, 4);
>> +	oobregion->length = mtd->oobsize - oobregion->offset;
>> +
>> +	return 0;
>> +}
>> +
>> +/*
>> + * Layout with tag bytes is
>> + *
>> + * --------------------------------------------------------------------------
>> + * | main area                       | skip bytes | tag bytes | parity | .. |
>> + * --------------------------------------------------------------------------
>> + *
>> + * If not tag bytes are written, parity moves right after skip bytes!
>> + */
>> +static const struct mtd_ooblayout_ops tegra_nand_oob_bch_ops = {
>> +	.ecc = tegra_nand_ooblayout_bch_ecc,
>> +	.free = tegra_nand_ooblayout_bch_free,
>> +};
>> +
>> +static irqreturn_t tegra_nand_irq(int irq, void *data)
>> +{
>> +	struct tegra_nand_controller *ctrl = data;
>> +	u32 isr, dma;
>> +
>> +	isr = readl_relaxed(ctrl->regs + ISR);
>> +	dma = readl_relaxed(ctrl->regs + DMA_CTRL);
>> +	dev_dbg(ctrl->dev, "isr %08x\n", isr);
>> +
>> +	if (!isr && !(dma & DMA_CTRL_IS_DONE))
>> +		return IRQ_NONE;
>> +
>> +	/*
>> +	 * The bit name is somewhat missleading: This is also set when
>> +	 * HW ECC was successful. The data sheet states:
>> +	 * Correctable OR Un-correctable errors occurred in the DMA transfer...
>> +	 */
>> +	if (isr & ISR_CORRFAIL_ERR)
>> +		ctrl->last_read_error = true;
>> +
>> +	if (isr & ISR_CMD_DONE)
>> +		complete(&ctrl->command_complete);
>> +
>> +	if (isr & ISR_UND)
>> +		dev_err(ctrl->dev, "FIFO underrun\n");
>> +
>> +	if (isr & ISR_OVR)
>> +		dev_err(ctrl->dev, "FIFO overrun\n");
>> +
>> +	/* handle DMA interrupts */
>> +	if (dma & DMA_CTRL_IS_DONE) {
>> +		writel_relaxed(dma, ctrl->regs + DMA_CTRL);
>> +		complete(&ctrl->dma_complete);
>> +	}
>> +
>> +	/* clear interrupts */
>> +	writel_relaxed(isr, ctrl->regs + ISR);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static const char * const tegra_nand_reg_names[] = {
>> +	"COMMAND",
>> +	"STATUS",
>> +	"ISR",
>> +	"IER",
>> +	"CONFIG",
>> +	"TIMING",
>> +	NULL,
>> +	"TIMING2",
>> +	"CMD_REG1",
>> +	"CMD_REG2",
>> +	"ADDR_REG1",
>> +	"ADDR_REG2",
>> +	"DMA_MST_CTRL",
>> +	"DMA_CFG_A",
>> +	"DMA_CFG_B",
>> +	"FIFO_CTRL",
>> +};
>> +
>> +static void tegra_nand_dump_reg(struct tegra_nand_controller *ctrl)
>> +{
>> +	u32 reg;
>> +	int i;
>> +
>> +	dev_err(ctrl->dev, "Tegra NAND controller register dump\n");
>> +	for (i = 0; i < ARRAY_SIZE(tegra_nand_reg_names); i++) {
>> +		const char *reg_name = tegra_nand_reg_names[i];
>> +
>> +		if (!reg_name)
>> +			continue;
>> +
>> +		reg = readl_relaxed(ctrl->regs + (i * 4));
>> +		dev_err(ctrl->dev, "%s: 0x%08x\n", reg_name, reg);
>> +	}
>> +}
>> +
>> +static int tegra_nand_cmd(struct nand_chip *chip,
>> +			 const struct nand_subop *subop)
>> +{
>> +	const struct nand_op_instr *instr;
>> +	const struct nand_op_instr *instr_data_in = NULL;
>> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>> +	unsigned int op_id, size = 0, offset = 0;
>> +	bool first_cmd = true;
>> +	u32 reg, cmd = 0;
>> +	int ret;
>> +
>> +	for (op_id = 0; op_id < subop->ninstrs; op_id++) {
>> +		unsigned int naddrs, i;
>> +		const u8 *addrs;
>> +		u32 addr1 = 0, addr2 = 0;
>> +
>> +		instr = &subop->instrs[op_id];
>> +
>> +		switch (instr->type) {
>> +		case NAND_OP_CMD_INSTR:
>> +			if (first_cmd) {
>> +				cmd |= CMD_CLE;
>> +				writel_relaxed(instr->ctx.cmd.opcode,
>> +					       ctrl->regs + CMD_1);
>> +			} else {
>> +				cmd |= CMD_SEC_CMD;
>> +				writel_relaxed(instr->ctx.cmd.opcode,
>> +					       ctrl->regs + CMD_2);
>> +			}
>> +			first_cmd = false;
>> +			break;
>> +		case NAND_OP_ADDR_INSTR:
>> +			offset = nand_subop_get_addr_start_off(subop, op_id);
>> +			naddrs = nand_subop_get_num_addr_cyc(subop, op_id);
>> +			addrs = &instr->ctx.addr.addrs[offset];
>> +
>> +			cmd |= CMD_ALE | CMD_ALE_SIZE(naddrs);
>> +			for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
>> +				addr1 |= *addrs++ << (BITS_PER_BYTE * i);
>> +			naddrs -= i;
>> +			for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
>> +				addr2 |= *addrs++ << (BITS_PER_BYTE * i);
>> +			writel_relaxed(addr1, ctrl->regs + ADDR_1);
>> +			writel_relaxed(addr2, ctrl->regs + ADDR_2);
>> +			break;
>> +
>> +		case NAND_OP_DATA_IN_INSTR:
>> +			size = nand_subop_get_data_len(subop, op_id);
>> +			offset = nand_subop_get_data_start_off(subop, op_id);
>> +
>> +			cmd |= CMD_TRANS_SIZE(size) | CMD_PIO | CMD_RX |
>> +				CMD_A_VALID;
>> +
>> +			instr_data_in = instr;
>> +			break;
>> +
>> +		case NAND_OP_DATA_OUT_INSTR:
>> +			size = nand_subop_get_data_len(subop, op_id);
>> +			offset = nand_subop_get_data_start_off(subop, op_id);
>> +
>> +			cmd |= CMD_TRANS_SIZE(size) | CMD_PIO | CMD_TX |
>> +				CMD_A_VALID;
>> +
>> +			memcpy(&reg, instr->ctx.data.buf.out + offset, size);
>> +			writel_relaxed(reg, ctrl->regs + RESP);
>> +
>> +			break;
>> +		case NAND_OP_WAITRDY_INSTR:
>> +			cmd |= CMD_RBSY_CHK;
>> +			break;
>> +
>> +		}
>> +	}
>> +
>> +	cmd |= CMD_GO | CMD_CE(ctrl->cur_chip);
>> +	writel_relaxed(cmd, ctrl->regs + CMD);
>> +	ret = wait_for_completion_timeout(&ctrl->command_complete,
>> +					  msecs_to_jiffies(500));
>> +	if (!ret) {
>> +		dev_err(ctrl->dev, "CMD timeout\n");
>> +		tegra_nand_dump_reg(ctrl);
>> +		return -ETIMEDOUT;
>> +	}
> 
> - wait_for_completion_timeout() could fail

Not according to:
https://elixir.bootlin.com/linux/latest/source/kernel/sched/completion.c#L140
https://www.kernel.org/doc/Documentation/scheduler/completion.txt

Afaik, only the _interruptible variant can fail.

Btw, maybe we should use the _io variant?


> - HW shall be reset
> - completion shall be re-inited because IRQ could fire just after the completion
> timeout
> 
> I'd write it something like this:
> 
> #define INT_MASK	(IER_UND | IER_OVR | IER_CMD_DONE | IER_GIE)
> 
> #define HWSTATUS_MASK	(HWSTATUS_RDSTATUS_MASK(1) |		 \
> 			 HWSTATUS_RDSTATUS_VALUE(0) |		 \
> 			 HWSTATUS_RBSY_MASK(NAND_STATUS_READY) | \
> 			 HWSTATUS_RBSY_VALUE(NAND_STATUS_READY))
> 
> #define HW_TIMEOUT	500
> 
> void tegra_nand_controller_reset(struct tegra_nand_controller *ctrl)
> {
> 	int err;
> 
> 	disable_irq(ctrl->irq);
> 
> 	err = reset_control_reset(ctrl->rst);
> 	if (err) {
> 		dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
> 		msleep(HW_TIMEOUT);
> 	}
> 
> 	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
> 	writel_relaxed(HWSTATUS_MASK, ctrl->regs + HWSTATUS_MASK);
> 	writel_relaxed(INT_MASK, ctrl->regs + ISR);

If we do a controller reset, there is much more state than that which
needs to be restored. A lot of it is not readily available currently
(timing, ECC settings...)

That seems a lot of work for a code path I do not intend to ever use :-)

--
Stefan

> 
> 	reinit_completion(&ctrl->command_complete);
> 	reinit_completion(&ctrl->dma_complete);
> 
> 	enable_irq(ctrl->irq);
> }
> 
> ...
> 
> 	ret = wait_for_completion_timeout(&ctrl->command_complete,
> 					  msecs_to_jiffies(HW_TIMEOUT));
> 	if (ret <= 0) {
> 		if (ret == 0) {
> 			dev_err(ctrl->dev, "CMD timeout\n");
> 			tegra_nand_dump_reg(ctrl);
> 			ret = -ETIMEDOUT;
> 		} else {
> 			dev_err(ctrl->dev,
> 				"Failed to wait for CMD completion: %d\n",
> 				ret);
> 		}
> 
> 		tegra_nand_controller_reset(ctrl);
> 		return ret;
> 	}
> 
>> +
>> +	if (instr_data_in) {
>> +		reg = readl_relaxed(ctrl->regs + RESP);
>> +		memcpy(instr_data_in->ctx.data.buf.in + offset, &reg, size);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct nand_op_parser tegra_nand_op_parser = NAND_OP_PARSER(
>> +	NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
>> +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
>> +		NAND_OP_PARSER_PAT_ADDR_ELEM(true, 8),
>> +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
>> +		NAND_OP_PARSER_PAT_WAITRDY_ELEM(true)),
>> +	NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
>> +		NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, 4)),
>> +	NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
>> +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
>> +		NAND_OP_PARSER_PAT_ADDR_ELEM(true, 8),
>> +		NAND_OP_PARSER_PAT_CMD_ELEM(true),
>> +		NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
>> +		NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, 4)),
>> +	);
>> +
>> +static int tegra_nand_exec_op(struct nand_chip *chip,
>> +			     const struct nand_operation *op,
>> +			     bool check_only)
>> +{
>> +	return nand_op_parser_exec_op(chip, &tegra_nand_op_parser, op,
>> +				      check_only);
>> +}
>> +static void tegra_nand_select_chip(struct mtd_info *mtd, int chip_nr)
>> +{
>> +	struct nand_chip *chip = mtd_to_nand(mtd);
>> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>> +
>> +	ctrl->cur_chip = chip_nr;
>> +}
>> +
>> +static void tegra_nand_hw_ecc(struct tegra_nand_controller *ctrl,
>> +			      struct nand_chip *chip, bool enable)
>> +{
>> +	u32 reg;
>> +
>> +	switch (chip->ecc.algo) {
>> +	case NAND_ECC_RS:
>> +		reg = readl_relaxed(ctrl->regs + CFG);
>> +		if (enable)
>> +			reg |= CFG_HW_ECC | CFG_ERR_COR;
>> +		else
>> +			reg &= ~(CFG_HW_ECC | CFG_ERR_COR);
>> +		writel_relaxed(reg, ctrl->regs + CFG);
>> +		break;
>> +	case NAND_ECC_BCH:
>> +		reg = readl_relaxed(ctrl->regs + BCH_CONFIG);
>> +		if (enable)
>> +			reg |= BCH_ENABLE;
>> +		else
>> +			reg &= ~BCH_ENABLE;
>> +		writel_relaxed(reg, ctrl->regs + BCH_CONFIG);
>> +		break;
>> +	default:
>> +		dev_err(ctrl->dev, "Unsupported hardware ECC algorithm\n");
>> +		break;
>> +	}
>> +}
>> +
>> +static int tegra_nand_page_xfer(struct mtd_info *mtd, struct nand_chip *chip,
>> +				void *buf, int oob_required, int page,
>> +				bool read)
>> +{
>> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>> +	struct tegra_nand_chip *nand = to_tegra_chip(chip);
>> +	enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
>> +	dma_addr_t dma_addr;
>> +	u32 cmd, dma_ctrl;
>> +	int ret, dma_len;
>> +
>> +	if (read) {
>> +		writel_relaxed(NAND_CMD_READ0, ctrl->regs + CMD_1);
>> +		writel_relaxed(NAND_CMD_READSTART, ctrl->regs + CMD_2);
>> +	} else {
>> +		writel_relaxed(NAND_CMD_SEQIN, ctrl->regs + CMD_1);
>> +		writel_relaxed(NAND_CMD_PAGEPROG, ctrl->regs + CMD_2);
>> +	}
>> +	cmd = CMD_CLE | CMD_SEC_CMD;
>> +
>> +	/* Lower 16-bits are column, always 0 */
>> +	writel_relaxed(page << 16, ctrl->regs + ADDR_1);
>> +
>> +	if (chip->options & NAND_ROW_ADDR_3) {
>> +		writel_relaxed(page >> 16, ctrl->regs + ADDR_2);
>> +		cmd |= CMD_ALE | CMD_ALE_SIZE(5);
>> +	} else {
>> +		cmd |= CMD_ALE | CMD_ALE_SIZE(4);
>> +	}
>> +
>> +	dma_len = mtd->writesize + (oob_required ? mtd->oobsize : 0);
>> +	dma_addr = dma_map_single(ctrl->dev, buf, dma_len, dir);
>> +	ret = dma_mapping_error(ctrl->dev, dma_addr);
>> +	if (ret) {
>> +		dev_err(ctrl->dev, "dma mapping error\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	writel_relaxed(mtd->writesize - 1, ctrl->regs + DMA_CFG_A);
>> +	writel_relaxed(dma_addr, ctrl->regs + DATA_PTR);
>> +
>> +	if (oob_required) {
>> +		dma_addr_t dma_addr_tag = dma_addr + mtd->writesize;
>> +
>> +		writel_relaxed(nand->tag.length - 1, ctrl->regs + DMA_CFG_B);
>> +		writel_relaxed(dma_addr_tag + nand->tag.offset,
>> +			       ctrl->regs + TAG_PTR);
>> +	} else {
>> +		writel_relaxed(0, ctrl->regs + DMA_CFG_B);
>> +		writel_relaxed(0, ctrl->regs + TAG_PTR);
>> +	}
>> +
>> +	dma_ctrl = DMA_CTRL_GO | DMA_CTRL_PERF_EN |
>> +		   DMA_CTRL_IE_DONE | DMA_CTRL_IS_DONE |
>> +		   DMA_CTRL_BURST_16 | DMA_CTRL_EN_A;
>> +	if (oob_required)
>> +		dma_ctrl |= DMA_CTRL_EN_B;
>> +	if (read)
>> +		dma_ctrl |= DMA_CTRL_IN | DMA_CTRL_REUSE;
>> +	else
>> +		dma_ctrl |= DMA_CTRL_OUT;
>> +
>> +	writel_relaxed(dma_ctrl, ctrl->regs + DMA_CTRL);
>> +
>> +	cmd |= CMD_GO | CMD_RBSY_CHK | CMD_TRANS_SIZE(9) |
>> +	       CMD_CE(ctrl->cur_chip) | CMD_A_VALID;
>> +	if (oob_required)
>> +		cmd |= CMD_B_VALID;
>> +	if (read)
>> +		cmd |= CMD_RX;
>> +	else
>> +		cmd |= CMD_TX | CMD_AFT_DAT;
>> +
>> +	writel_relaxed(cmd, ctrl->regs + CMD);
>> +
>> +	ret = wait_for_completion_timeout(&ctrl->command_complete,
>> +					  msecs_to_jiffies(500));
>> +	if (!ret) {
>> +		dev_err(ctrl->dev, "CMD timeout\n");
>> +		tegra_nand_dump_reg(ctrl);
>> +		ret = -ETIMEDOUT;
>> +		goto err_unmap_dma;
>> +	}
>> +
>> +	ret = wait_for_completion_timeout(&ctrl->dma_complete,
>> +					  msecs_to_jiffies(500));
>> +	if (!ret) {
>> +		dev_err(ctrl->dev, "DMA timeout\n");
>> +		tegra_nand_dump_reg(ctrl);
>> +		ret = -ETIMEDOUT;
>> +		goto err_unmap_dma;
>> +	}
>> +	ret = 0;
> 
> Same as the above comment regarding the wait_for_completion_timeout().
> 
>> +
>> +err_unmap_dma:
>> +	dma_unmap_single(ctrl->dev, dma_addr, dma_len, dir);
>> +
>> +	return ret;
>> +}
>> +
>> +static int tegra_nand_read_page_hwecc(struct mtd_info *mtd,
>> +				      struct nand_chip *chip,
>> +				      uint8_t *buf, int oob_required, int page)
>> +{
>> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>> +	u32 dec_stat, max_corr_cnt;
>> +	unsigned long fail_sec_flag;
>> +	int ret;
>> +
>> +	tegra_nand_hw_ecc(ctrl, chip, true);
>> +	ret = tegra_nand_page_xfer(mtd, chip, buf, oob_required, page, true);
>> +	tegra_nand_hw_ecc(ctrl, chip, false);
>> +	if (ret)
>> +		return ret;
>> +
>> +	/* No correctable or un-correctable errors, page must have 0 bitflips */
>> +	if (!ctrl->last_read_error)
>> +		return 0;
>> +
>> +	/*
>> +	 * Correctable or un-correctable errors occurred. Use DEC_STAT_BUF
>> +	 * which contains information for all ECC selections.
>> +	 *
>> +	 * Note that since we do not use Command Queues DEC_RESULT does not
>> +	 * state the number of pages we can read from the DEC_STAT_BUF. But
>> +	 * since CORRFAIL_ERR did occur during page read we do have a valid
>> +	 * result in DEC_STAT_BUF.
>> +	 */
>> +	ctrl->last_read_error = false;
>> +	dec_stat = readl_relaxed(ctrl->regs + DEC_STAT_BUF);
>> +
>> +	fail_sec_flag = (dec_stat & DEC_STAT_BUF_FAIL_SEC_FLAG_MASK) >>
>> +			DEC_STAT_BUF_FAIL_SEC_FLAG_SHIFT;
>> +
>> +	max_corr_cnt = (dec_stat & DEC_STAT_BUF_MAX_CORR_CNT_MASK) >>
>> +		       DEC_STAT_BUF_MAX_CORR_CNT_SHIFT;
>> +
>> +	if (fail_sec_flag) {
>> +		int bit, max_bitflips = 0;
>> +
>> +		/*
>> +		 * Check if all sectors in a page failed. If only some failed
>> +		 * its definitly not an erased page and we can return error
>> +		 * stats right away.
>> +		 *
>> +		 * E.g. controller might return fail_sec_flag with 0x4, which
>> +		 * would mean only the third sector failed to correct.
>> +		 */
>> +		if (fail_sec_flag ^ GENMASK(chip->ecc.steps - 1, 0)) {
>> +			mtd->ecc_stats.failed += hweight8(fail_sec_flag);
>> +			return max_corr_cnt;
>> +		}
>> +
>> +		/*
>> +		 * All sectors failed to correct, but the ECC isn't smart
>> +		 * enough to figure out if a page is really completely erased.
>> +		 * We check the read data here to figure out if it's a
>> +		 * legitimate ECC error or only an erased page.
>> +		 */
>> +		for_each_set_bit(bit, &fail_sec_flag, chip->ecc.steps) {
>> +			u8 *data = buf + (chip->ecc.size * bit);
>> +
>> +			ret = nand_check_erased_ecc_chunk(data, chip->ecc.size,
>> +							  NULL, 0,
>> +							  NULL, 0,
>> +							  chip->ecc.strength);
>> +			if (ret < 0)
>> +				mtd->ecc_stats.failed++;
>> +			else
>> +				max_bitflips = max(ret, max_bitflips);
>> +		}
>> +
>> +		return max_t(unsigned int, max_corr_cnt, max_bitflips);
>> +	} else {
>> +		int corr_sec_flag;
>> +
>> +		corr_sec_flag = (dec_stat & DEC_STAT_BUF_CORR_SEC_FLAG_MASK) >>
>> +				DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT;
>> +
>> +		/*
>> +		 * The value returned in the register is the maximum of
>> +		 * bitflips encountered in any of the ECC regions. As there is
>> +		 * no way to get the number of bitflips in a specific regions
>> +		 * we are not able to deliver correct stats but instead
>> +		 * overestimate the number of corrected bitflips by assuming
>> +		 * that all regions where errors have been corrected
>> +		 * encountered the maximum number of bitflips.
>> +		 */
>> +		mtd->ecc_stats.corrected += max_corr_cnt * hweight8(corr_sec_flag);
>> +
>> +		return max_corr_cnt;
>> +	}
>> +
>> +}
>> +
>> +static int tegra_nand_write_page_hwecc(struct mtd_info *mtd,
>> +				       struct nand_chip *chip,
>> +				       const uint8_t *buf, int oob_required,
>> +				       int page)
>> +{
>> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>> +	int ret;
>> +
>> +	tegra_nand_hw_ecc(ctrl, chip, true);
>> +	ret = tegra_nand_page_xfer(mtd, chip, (void *)buf, oob_required, page,
>> +				   false);
>> +	tegra_nand_hw_ecc(ctrl, chip, false);
>> +
>> +	return ret;
>> +}
>> +
>> +static void tegra_nand_setup_timing(struct tegra_nand_controller *ctrl,
>> +				    const struct nand_sdr_timings *timings)
>> +{
>> +	/*
>> +	 * The period (and all other timings in this function) is in ps,
>> +	 * so need to take care here to avoid integer overflows.
>> +	 */
>> +	unsigned int rate = clk_get_rate(ctrl->clk) / 1000000;
>> +	unsigned int period = DIV_ROUND_UP(1000000, rate);
>> +	u32 val, reg = 0;
>> +
>> +	val = DIV_ROUND_UP(max3(timings->tAR_min, timings->tRR_min,
>> +				timings->tRC_min), period);
>> +	reg |= TIMING_TCR_TAR_TRR(OFFSET(val, 3));
>> +
>> +	val = DIV_ROUND_UP(max(max(timings->tCS_min, timings->tCH_min),
>> +			       max(timings->tALS_min, timings->tALH_min)),
>> +			   period);
>> +	reg |= TIMING_TCS(OFFSET(val, 2));
>> +
>> +	val = DIV_ROUND_UP(max(timings->tRP_min, timings->tREA_max) + 6000,
>> +			   period);
>> +	reg |= TIMING_TRP(OFFSET(val, 1)) | TIMING_TRP_RESP(OFFSET(val, 1));
>> +
>> +	reg |= TIMING_TWB(OFFSET(DIV_ROUND_UP(timings->tWB_max, period), 1));
>> +	reg |= TIMING_TWHR(OFFSET(DIV_ROUND_UP(timings->tWHR_min, period), 1));
>> +	reg |= TIMING_TWH(OFFSET(DIV_ROUND_UP(timings->tWH_min, period), 1));
>> +	reg |= TIMING_TWP(OFFSET(DIV_ROUND_UP(timings->tWP_min, period), 1));
>> +	reg |= TIMING_TRH(OFFSET(DIV_ROUND_UP(timings->tREH_min, period), 1));
>> +
>> +	writel_relaxed(reg, ctrl->regs + TIMING_1);
>> +
>> +	val = DIV_ROUND_UP(timings->tADL_min, period);
>> +	reg = TIMING_TADL(OFFSET(val, 3));
>> +
>> +	writel_relaxed(reg, ctrl->regs + TIMING_2);
>> +}
>> +
>> +static int tegra_nand_setup_data_interface(struct mtd_info *mtd, int csline,
>> +					   const struct nand_data_interface *conf)
>> +{
>> +	struct nand_chip *chip = mtd_to_nand(mtd);
>> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>> +	const struct nand_sdr_timings *timings;
>> +
>> +	timings = nand_get_sdr_timings(conf);
>> +	if (IS_ERR(timings))
>> +		return PTR_ERR(timings);
>> +
>> +	if (csline == NAND_DATA_IFACE_CHECK_ONLY)
>> +		return 0;
>> +
>> +	tegra_nand_setup_timing(ctrl, timings);
>> +
>> +	return 0;
>> +}
>> +
>> +
>> +const int rs_strength_bootable[] = { 4 };
>> +const int rs_strength[] = { 4, 6, 8 };
>> +const int bch_strength_bootable[] = { 8, 16 };
>> +const int bch_strength[] = { 4, 8, 14, 16 };
> 
> These const's shall be 'static'.
> 
>> +
>> +static int tegra_nand_get_strength(struct nand_chip *chip, const int *strength,
>> +				   int strength_len, int oobsize)
>> +{
>> +	bool maximize = chip->ecc.options & NAND_ECC_MAXIMIZE;
>> +	int i;
>> +
>> +	/*
>> +	 * Loop through available strengths. Backwards in case we try to
>> +	 * maximize the BCH strength.
>> +	 */
>> +	for (i = 0; i < strength_len; i++) {
>> +		int strength_sel, bytes_per_step, bytes_per_page;
>> +
>> +		if (maximize) {
>> +			strength_sel = strength[strength_len - i - 1];
>> +		} else {
>> +			strength_sel = strength[i];
>> +
>> +			if (strength_sel < chip->ecc_strength_ds)
>> +				continue;
>> +		}
>> +
>> +		bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH * strength_sel,
>> +					      BITS_PER_BYTE);
>> +		bytes_per_page = round_up(bytes_per_step * chip->ecc.steps, 4);
>> +
>> +		/* Check whether strength fits OOB */
>> +		if (bytes_per_page < (oobsize - SKIP_SPARE_BYTES))
>> +			return strength_sel;
>> +	}
>> +
>> +	return -EINVAL;
>> +}
>> +
>> +static int tegra_nand_select_strength(struct nand_chip *chip, int oobsize)
>> +{
>> +	const int *strength;
>> +	int strength_len;
>> +
>> +	switch (chip->ecc.algo) {
>> +	case NAND_ECC_RS:
>> +		if (chip->options & NAND_IS_BOOT_MEDIUM) {
>> +			strength = rs_strength_bootable;
>> +			strength_len = ARRAY_SIZE(rs_strength_bootable);
>> +		} else {
>> +			strength = rs_strength;
>> +			strength_len = ARRAY_SIZE(rs_strength);
>> +		}
>> +		break;
>> +	case NAND_ECC_BCH:
>> +		if (chip->options & NAND_IS_BOOT_MEDIUM) {
>> +			strength = bch_strength_bootable;
>> +			strength_len = ARRAY_SIZE(bch_strength_bootable);
>> +		} else {
>> +			strength = bch_strength;
>> +			strength_len = ARRAY_SIZE(bch_strength);
>> +		}
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	return tegra_nand_get_strength(chip, strength, strength_len, oobsize);
>> +}
>> +
>> +static int tegra_nand_chips_init(struct device *dev,
>> +				 struct tegra_nand_controller *ctrl)
>> +{
>> +	struct device_node *np = dev->of_node;
>> +	struct device_node *np_nand;
>> +	int nchips = of_get_child_count(np);
>> +	struct tegra_nand_chip *nand;
>> +	struct mtd_info *mtd;
>> +	struct nand_chip *chip;
>> +	unsigned long config, bch_config = 0;
>> +	int bits_per_step;
>> +	int ret;
>> +
>> +	if (nchips != 1) {
>> +		dev_err(dev, "Currently only one NAND chip supported\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	np_nand = of_get_next_child(np, NULL);
>> +
>> +	nand = devm_kzalloc(dev, sizeof(*nand), GFP_KERNEL);
>> +	if (!nand)
>> +		return -ENOMEM;
>> +
>> +	nand->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_LOW);
>> +
>> +	if (IS_ERR(nand->wp_gpio)) {
>> +		ret = PTR_ERR(nand->wp_gpio);
>> +		dev_err(dev, "Failed to request WP GPIO: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	chip = &nand->chip;
>> +	chip->controller = &ctrl->controller;
>> +
>> +	mtd = nand_to_mtd(chip);
>> +
>> +	mtd->dev.parent = dev;
>> +	if (!mtd->name)
>> +		mtd->name = "tegra_nand";
>> +	mtd->owner = THIS_MODULE;
>> +
>> +	nand_set_flash_node(chip, np_nand);
>> +
>> +	chip->options = NAND_NO_SUBPAGE_WRITE | NAND_USE_BOUNCE_BUFFER;
>> +	chip->exec_op = tegra_nand_exec_op;
>> +	chip->select_chip = tegra_nand_select_chip;
>> +	chip->setup_data_interface = tegra_nand_setup_data_interface;
>> +
>> +	ret = nand_scan_ident(mtd, 1, NULL);
>> +	if (ret)
>> +		return ret;
>> +
>> +	if (chip->bbt_options & NAND_BBT_USE_FLASH)
>> +		chip->bbt_options |= NAND_BBT_NO_OOB;
>> +
>> +	chip->ecc.mode = NAND_ECC_HW;
>> +	chip->ecc.size = 512;
>> +	chip->ecc.steps = mtd->writesize / chip->ecc.size;
>> +	if (chip->ecc_step_ds != 512) {
>> +		dev_err(dev, "Unsupported step size %d\n", chip->ecc_step_ds);
>> +		return -EINVAL;
>> +	}
>> +
>> +	chip->ecc.read_page = tegra_nand_read_page_hwecc;
>> +	chip->ecc.write_page = tegra_nand_write_page_hwecc;
>> +
>> +	config = readl_relaxed(ctrl->regs + CFG);
>> +	config |= CFG_PIPE_EN | CFG_SKIP_SPARE | CFG_SKIP_SPARE_SIZE_4;
>> +
>> +	if (chip->options & NAND_BUSWIDTH_16)
>> +		config |= CFG_BUS_WIDTH_16;
>> +
>> +	if (chip->ecc.algo == NAND_ECC_UNKNOWN) {
>> +		if (mtd->writesize < 2048)
>> +			chip->ecc.algo = NAND_ECC_RS;
>> +		else
>> +			chip->ecc.algo = NAND_ECC_BCH;
>> +	}
>> +
>> +	if (chip->ecc.algo == NAND_ECC_BCH && mtd->writesize < 2048) {
>> +		dev_err(dev, "BCH supportes 2K or 4K page size only\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (!chip->ecc.strength) {
>> +		ret = tegra_nand_select_strength(chip, mtd->oobsize);
>> +		if (ret < 0) {
>> +			dev_err(dev, "No valid strenght found, minimum %d\n",
>> +				chip->ecc_strength_ds);
>> +			return ret;
>> +		}
>> +
>> +		chip->ecc.strength = ret;
>> +	}
>> +
>> +	switch (chip->ecc.algo) {
>> +	case NAND_ECC_RS:
>> +		bits_per_step = BITS_PER_STEP_RS * chip->ecc.strength;
>> +		mtd_set_ooblayout(mtd, &tegra_nand_oob_rs_ops);
>> +		switch (chip->ecc.strength) {
>> +		case 4:
>> +			config |= CFG_ECC_SEL | CFG_TVAL_4;
>> +			break;
>> +		case 6:
>> +			config |= CFG_ECC_SEL | CFG_TVAL_6;
>> +			break;
>> +		case 8:
>> +			config |= CFG_ECC_SEL | CFG_TVAL_8;
>> +			break;
>> +		default:
>> +			dev_err(dev, "ECC strength %d not supported\n",
>> +				chip->ecc.strength);
>> +			return -EINVAL;
>> +		}
>> +		break;
>> +	case NAND_ECC_BCH:
>> +		bits_per_step = BITS_PER_STEP_BCH * chip->ecc.strength;
>> +		mtd_set_ooblayout(mtd, &tegra_nand_oob_bch_ops);
>> +		switch (chip->ecc.strength) {
>> +		case 4:
>> +			bch_config = BCH_TVAL_4;
>> +			break;
>> +		case 8:
>> +			bch_config = BCH_TVAL_8;
>> +			break;
>> +		case 14:
>> +			bch_config = BCH_TVAL_14;
>> +			break;
>> +		case 16:
>> +			bch_config = BCH_TVAL_16;
>> +			break;
>> +		default:
>> +			dev_err(dev, "ECC strength %d not supported\n",
>> +				chip->ecc.strength);
>> +			return -EINVAL;
>> +		}
>> +		break;
>> +	default:
>> +		dev_err(dev, "ECC algorithm not supported\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	dev_info(dev, "Using %s with strength %d per 512 byte step\n",
>> +			chip->ecc.algo == NAND_ECC_BCH ? "BCH" : "RS",
>> +			chip->ecc.strength);
>> +
>> +	chip->ecc.bytes = DIV_ROUND_UP(bits_per_step, BITS_PER_BYTE);
>> +
>> +	switch (mtd->writesize) {
>> +	case 256:
>> +		config |= CFG_PS_256;
>> +		break;
>> +	case 512:
>> +		config |= CFG_PS_512;
>> +		break;
>> +	case 1024:
>> +		config |= CFG_PS_1024;
>> +		break;
>> +	case 2048:
>> +		config |= CFG_PS_2048;
>> +		break;
>> +	case 4096:
>> +		config |= CFG_PS_4096;
>> +		break;
>> +	default:
>> +		dev_err(dev, "Unsupported writesize %d\n", mtd->writesize);
>> +		return -ENODEV;
>> +	}
>> +
>> +	writel_relaxed(config, ctrl->regs + CFG);
>> +	writel_relaxed(bch_config, ctrl->regs + BCH_CONFIG);
>> +
>> +	ret = nand_scan_tail(mtd);
>> +	if (ret)
>> +		return ret;
>> +
>> +	mtd_ooblayout_free(mtd, 0, &nand->tag);
>> +
>> +	config |= CFG_TAG_BYTE_SIZE(nand->tag.length - 1);
>> +	writel_relaxed(config, ctrl->regs + CFG);
>> +
>> +	ret = mtd_device_register(mtd, NULL, 0);
>> +	if (ret) {
>> +		dev_err(dev, "Failed to register mtd device: %d\n", ret);
>> +		nand_cleanup(chip);
>> +		return ret;
>> +	}
>> +
>> +	ctrl->chip = chip;
>> +
>> +	return 0;
>> +}
>> +
>> +static int tegra_nand_probe(struct platform_device *pdev)
>> +{
>> +	struct reset_control *rst;
>> +	struct tegra_nand_controller *ctrl;
>> +	struct resource *res;
>> +	unsigned long reg;
>> +	int irq, err = 0;
>> +
>> +	ctrl = devm_kzalloc(&pdev->dev, sizeof(*ctrl), GFP_KERNEL);
>> +	if (!ctrl)
>> +		return -ENOMEM;
>> +
>> +	ctrl->dev = &pdev->dev;
>> +	nand_hw_control_init(&ctrl->controller);
>> +
>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	ctrl->regs = devm_ioremap_resource(&pdev->dev, res);
>> +	if (IS_ERR(ctrl->regs))
>> +		return PTR_ERR(ctrl->regs);
>> +
>> +	rst = devm_reset_control_get(&pdev->dev, "nand");
>> +	if (IS_ERR(rst))
>> +		return PTR_ERR(rst);
>> +
>> +	ctrl->clk = devm_clk_get(&pdev->dev, "nand");
>> +	if (IS_ERR(ctrl->clk))
>> +		return PTR_ERR(ctrl->clk);
>> +
>> +	err = clk_prepare_enable(ctrl->clk);
>> +	if (err)
>> +		return err;
>> +
>> +	err = reset_control_reset(rst);
>> +	if (err)
>> +		goto err_disable_clk;
>> +
>> +	reg = HWSTATUS_RDSTATUS_MASK(1) | HWSTATUS_RDSTATUS_VALUE(0) |
>> +		HWSTATUS_RBSY_MASK(NAND_STATUS_READY) |
>> +		HWSTATUS_RBSY_VALUE(NAND_STATUS_READY);
>> +	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
>> +	writel_relaxed(reg, ctrl->regs + HWSTATUS_MASK);
>> +
>> +	init_completion(&ctrl->command_complete);
>> +	init_completion(&ctrl->dma_complete);
>> +
>> +	/* clear interrupts */
>> +	reg = readl_relaxed(ctrl->regs + ISR);
>> +	writel_relaxed(reg, ctrl->regs + ISR);
>> +
>> +	irq = platform_get_irq(pdev, 0);
>> +	err = devm_request_irq(&pdev->dev, irq, tegra_nand_irq, 0,
>> +			       dev_name(&pdev->dev), ctrl);
>> +	if (err)
>> +		goto err_disable_clk;
>> +
>> +	writel_relaxed(DMA_CTRL_IS_DONE, ctrl->regs + DMA_CTRL);
>> +
>> +	/* enable interrupts */
>> +	reg = IER_UND | IER_OVR | IER_CMD_DONE | IER_GIE;
>> +	writel_relaxed(reg, ctrl->regs + IER);
>> +
>> +	/* reset config */
>> +	writel_relaxed(0, ctrl->regs + CFG);
>> +
>> +	err = tegra_nand_chips_init(ctrl->dev, ctrl);
>> +	if (err)
>> +		goto err_disable_clk;
>> +
>> +	platform_set_drvdata(pdev, ctrl);
>> +
>> +	return 0;
>> +
>> +err_disable_clk:
>> +	clk_disable_unprepare(ctrl->clk);
>> +	return err;
>> +}
>> +
>> +static int tegra_nand_remove(struct platform_device *pdev)
>> +{
>> +	struct tegra_nand_controller *ctrl = platform_get_drvdata(pdev);
>> +
>> +	nand_release(nand_to_mtd(ctrl->chip));
>> +
>> +	clk_disable_unprepare(ctrl->clk);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id tegra_nand_of_match[] = {
>> +	{ .compatible = "nvidia,tegra20-nand" },
>> +	{ /* sentinel */ }
>> +};
>> +
>> +static struct platform_driver tegra_nand_driver = {
>> +	.driver = {
>> +		.name = "tegra-nand",
>> +		.of_match_table = tegra_nand_of_match,
>> +	},
>> +	.probe = tegra_nand_probe,
>> +	.remove = tegra_nand_remove,
>> +};
>> +module_platform_driver(tegra_nand_driver);
>> +
>> +MODULE_DESCRIPTION("NVIDIA Tegra NAND driver");
>> +MODULE_AUTHOR("Thierry Reding <thierry.reding@nvidia.com>");
>> +MODULE_AUTHOR("Lucas Stach <dev@lynxeye.de>");
>> +MODULE_AUTHOR("Stefan Agner <stefan@agner.ch>");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_DEVICE_TABLE(of, tegra_nand_of_match);
>>
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On Fri, 08 Jun 2018 23:51:01 +0200
Stefan Agner <stefan@agner.ch> wrote:


> > 
> > void tegra_nand_controller_reset(struct tegra_nand_controller *ctrl)
> > {
> > 	int err;
> > 
> > 	disable_irq(ctrl->irq);
> > 
> > 	err = reset_control_reset(ctrl->rst);
> > 	if (err) {
> > 		dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
> > 		msleep(HW_TIMEOUT);
> > 	}
> > 
> > 	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
> > 	writel_relaxed(HWSTATUS_MASK, ctrl->regs + HWSTATUS_MASK);
> > 	writel_relaxed(INT_MASK, ctrl->regs + ISR);  
> 
> If we do a controller reset, there is much more state than that which
> needs to be restored. A lot of it is not readily available currently
> (timing, ECC settings...)

This is actually a good test to detect what is not properly initialized
by the driver. Timings should be configured correctly through
->setup_data_interface(). ECC engine should be disabled by default and
only enabled when ->{read,write}_page() is called.

> 
> That seems a lot of work for a code path I do not intend to ever use :-)
> 

Not so sure it's a lot of work. If ECC and timing settings are the
only thing you need to initialize then it should work just fine.
Try with a controller reset and you'll know if you miss something ;-).
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On Fri,  1 Jun 2018 00:16:35 +0200
Stefan Agner <stefan@agner.ch> wrote:

> +
> +static const struct of_device_id tegra_nand_of_match[] = {
> +	{ .compatible = "nvidia,tegra20-nand" },
> +	{ /* sentinel */ }
> +};
> +
> +static struct platform_driver tegra_nand_driver = {
> +	.driver = {
> +		.name = "tegra-nand",
> +		.of_match_table = tegra_nand_of_match,
> +	},
> +	.probe = tegra_nand_probe,
> +	.remove = tegra_nand_remove,
> +};
> +module_platform_driver(tegra_nand_driver);
> +
> +MODULE_DESCRIPTION("NVIDIA Tegra NAND driver");
> +MODULE_AUTHOR("Thierry Reding <thierry.reding@nvidia.com>");
> +MODULE_AUTHOR("Lucas Stach <dev@lynxeye.de>");
> +MODULE_AUTHOR("Stefan Agner <stefan@agner.ch>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_DEVICE_TABLE(of, tegra_nand_of_match);

Just a nitpick: can you move this MODULE_DEVICE_TABLE() just after the
tegra_nand_of_match declaration?

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On 09.06.2018 07:52, Boris Brezillon wrote:
> On Fri, 08 Jun 2018 23:51:01 +0200
> Stefan Agner <stefan@agner.ch> wrote:
> 
> 
>> >
>> > void tegra_nand_controller_reset(struct tegra_nand_controller *ctrl)
>> > {
>> > 	int err;
>> >
>> > 	disable_irq(ctrl->irq);
>> >
>> > 	err = reset_control_reset(ctrl->rst);
>> > 	if (err) {
>> > 		dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
>> > 		msleep(HW_TIMEOUT);
>> > 	}
>> >
>> > 	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
>> > 	writel_relaxed(HWSTATUS_MASK, ctrl->regs + HWSTATUS_MASK);
>> > 	writel_relaxed(INT_MASK, ctrl->regs + ISR);
>>
>> If we do a controller reset, there is much more state than that which
>> needs to be restored. A lot of it is not readily available currently
>> (timing, ECC settings...)
> 
> This is actually a good test to detect what is not properly initialized
> by the driver. Timings should be configured correctly through
> ->setup_data_interface(). ECC engine should be disabled by default and
> only enabled when ->{read,write}_page() is called.
> 

Is setup_data_interface guaranteed to be called after a failed
->exec_op()/{read,write}_page()?

>>
>> That seems a lot of work for a code path I do not intend to ever use :-)
>>
> 
> Not so sure it's a lot of work. If ECC and timing settings are the
> only thing you need to initialize then it should work just fine.
> Try with a controller reset and you'll know if you miss something ;-).

Currently the setting gets written directly to the registers. Only the
enable flag is set in the HW ECC {read,write}_page() functions. So I
will have to store the complete register in the chip structure and write
them on every {read,write}_page()?

--
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On Sat, 09 Jun 2018 08:23:51 +0200
Stefan Agner <stefan@agner.ch> wrote:

> On 09.06.2018 07:52, Boris Brezillon wrote:
> > On Fri, 08 Jun 2018 23:51:01 +0200
> > Stefan Agner <stefan@agner.ch> wrote:
> > 
> >   
> >> >
> >> > void tegra_nand_controller_reset(struct tegra_nand_controller *ctrl)
> >> > {
> >> > 	int err;
> >> >
> >> > 	disable_irq(ctrl->irq);
> >> >
> >> > 	err = reset_control_reset(ctrl->rst);
> >> > 	if (err) {
> >> > 		dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
> >> > 		msleep(HW_TIMEOUT);
> >> > 	}
> >> >
> >> > 	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
> >> > 	writel_relaxed(HWSTATUS_MASK, ctrl->regs + HWSTATUS_MASK);
> >> > 	writel_relaxed(INT_MASK, ctrl->regs + ISR);  
> >>
> >> If we do a controller reset, there is much more state than that which
> >> needs to be restored. A lot of it is not readily available currently
> >> (timing, ECC settings...)  
> > 
> > This is actually a good test to detect what is not properly initialized
> > by the driver. Timings should be configured correctly through  
> > ->setup_data_interface(). ECC engine should be disabled by default and  
> > only enabled when ->{read,write}_page() is called.
> >   
> 
> Is setup_data_interface guaranteed to be called after a failed
> ->exec_op()/{read,write}_page()?

No. Maybe I misunderstood when tegra_nand_controller_reset() was
supposed to be called. That's something I would call only once, early
in the probe function, so that the controller is placed in a well-known
state before we start using it. Definitely not something you should
call after each error.

> 
> >>
> >> That seems a lot of work for a code path I do not intend to ever use :-)
> >>  
> > 
> > Not so sure it's a lot of work. If ECC and timing settings are the
> > only thing you need to initialize then it should work just fine.
> > Try with a controller reset and you'll know if you miss something ;-).  
> 
> Currently the setting gets written directly to the registers. Only the
> enable flag is set in the HW ECC {read,write}_page() functions. So I
> will have to store the complete register in the chip structure and write
> them on every {read,write}_page()?

Well, your solution works as long as you only have one chip connected
to the controller. What we usually set the ECC config in
->select_chip() (or at least make sure the current setting matches the
one we expect) and then enable the engine in read/write_page() (as you
seem to already do).
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On Sat, 9 Jun 2018 08:41:57 +0200
Boris Brezillon <boris.brezillon@bootlin.com> wrote:

> On Sat, 09 Jun 2018 08:23:51 +0200
> Stefan Agner <stefan@agner.ch> wrote:
> 
> > On 09.06.2018 07:52, Boris Brezillon wrote:
> > > On Fri, 08 Jun 2018 23:51:01 +0200
> > > Stefan Agner <stefan@agner.ch> wrote:
> > > 
> > >   
> > >> >
> > >> > void tegra_nand_controller_reset(struct tegra_nand_controller *ctrl)
> > >> > {
> > >> > 	int err;
> > >> >
> > >> > 	disable_irq(ctrl->irq);
> > >> >
> > >> > 	err = reset_control_reset(ctrl->rst);
> > >> > 	if (err) {
> > >> > 		dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
> > >> > 		msleep(HW_TIMEOUT);
> > >> > 	}
> > >> >
> > >> > 	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
> > >> > 	writel_relaxed(HWSTATUS_MASK, ctrl->regs + HWSTATUS_MASK);
> > >> > 	writel_relaxed(INT_MASK, ctrl->regs + ISR);  
> > >>
> > >> If we do a controller reset, there is much more state than that which
> > >> needs to be restored. A lot of it is not readily available currently
> > >> (timing, ECC settings...)  
> > > 
> > > This is actually a good test to detect what is not properly initialized
> > > by the driver. Timings should be configured correctly through  
> > > ->setup_data_interface(). ECC engine should be disabled by default and  
> > > only enabled when ->{read,write}_page() is called.
> > >   
> > 
> > Is setup_data_interface guaranteed to be called after a failed
> > ->exec_op()/{read,write}_page()?
> 
> No. Maybe I misunderstood when tegra_nand_controller_reset() was
> supposed to be called. That's something I would call only once, early
> in the probe function, so that the controller is placed in a well-known
> state before we start using it. Definitely not something you should
> call after each error.

Note that if you really want to reset the controller after an error,
you should also iterate over all chips and call nand_reset() on them.
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On 09.06.2018 08:41, Boris Brezillon wrote:
> On Sat, 09 Jun 2018 08:23:51 +0200
> Stefan Agner <stefan@agner.ch> wrote:
> 
>> On 09.06.2018 07:52, Boris Brezillon wrote:
>> > On Fri, 08 Jun 2018 23:51:01 +0200
>> > Stefan Agner <stefan@agner.ch> wrote:
>> >
>> >
>> >> >
>> >> > void tegra_nand_controller_reset(struct tegra_nand_controller *ctrl)
>> >> > {
>> >> > 	int err;
>> >> >
>> >> > 	disable_irq(ctrl->irq);
>> >> >
>> >> > 	err = reset_control_reset(ctrl->rst);
>> >> > 	if (err) {
>> >> > 		dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
>> >> > 		msleep(HW_TIMEOUT);
>> >> > 	}
>> >> >
>> >> > 	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
>> >> > 	writel_relaxed(HWSTATUS_MASK, ctrl->regs + HWSTATUS_MASK);
>> >> > 	writel_relaxed(INT_MASK, ctrl->regs + ISR);
>> >>
>> >> If we do a controller reset, there is much more state than that which
>> >> needs to be restored. A lot of it is not readily available currently
>> >> (timing, ECC settings...)
>> >
>> > This is actually a good test to detect what is not properly initialized
>> > by the driver. Timings should be configured correctly through
>> > ->setup_data_interface(). ECC engine should be disabled by default and
>> > only enabled when ->{read,write}_page() is called.
>> >
>>
>> Is setup_data_interface guaranteed to be called after a failed
>> ->exec_op()/{read,write}_page()?
> 
> No. Maybe I misunderstood when tegra_nand_controller_reset() was
> supposed to be called. That's something I would call only once, early
> in the probe function, so that the controller is placed in a well-known
> state before we start using it. Definitely not something you should
> call after each error.
> 

Dmitry suggests to make use of it in the error handling path in case the
command/DMA  timed out.

Which makes sense in general I guess, just to make sure that the state
is properly set. It just isn't entirely trivial to do, since state is
setup during probe, chip detect and timing setup...

>>
>> >>
>> >> That seems a lot of work for a code path I do not intend to ever use :-)
>> >>
>> >
>> > Not so sure it's a lot of work. If ECC and timing settings are the
>> > only thing you need to initialize then it should work just fine.
>> > Try with a controller reset and you'll know if you miss something ;-).
>>
>> Currently the setting gets written directly to the registers. Only the
>> enable flag is set in the HW ECC {read,write}_page() functions. So I
>> will have to store the complete register in the chip structure and write
>> them on every {read,write}_page()?
> 
> Well, your solution works as long as you only have one chip connected
> to the controller. What we usually set the ECC config in
> ->select_chip() (or at least make sure the current setting matches the
> one we expect) and then enable the engine in read/write_page() (as you
> seem to already do).

I did not plan to make the driver multi chip capable, as I am not aware
of any real hardware using it.

But to properly reset state, we would have to have all the chip settings
stored somewhere...

--
Stefan
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On Sat, 9 Jun 2018 08:46:15 +0200
Boris Brezillon <boris.brezillon@bootlin.com> wrote:

> On Sat, 9 Jun 2018 08:41:57 +0200
> Boris Brezillon <boris.brezillon@bootlin.com> wrote:
> 
> > On Sat, 09 Jun 2018 08:23:51 +0200
> > Stefan Agner <stefan@agner.ch> wrote:
> >   
> > > On 09.06.2018 07:52, Boris Brezillon wrote:  
> > > > On Fri, 08 Jun 2018 23:51:01 +0200
> > > > Stefan Agner <stefan@agner.ch> wrote:
> > > > 
> > > >     
> > > >> >
> > > >> > void tegra_nand_controller_reset(struct tegra_nand_controller *ctrl)
> > > >> > {
> > > >> > 	int err;
> > > >> >
> > > >> > 	disable_irq(ctrl->irq);
> > > >> >
> > > >> > 	err = reset_control_reset(ctrl->rst);
> > > >> > 	if (err) {
> > > >> > 		dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
> > > >> > 		msleep(HW_TIMEOUT);
> > > >> > 	}
> > > >> >
> > > >> > 	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
> > > >> > 	writel_relaxed(HWSTATUS_MASK, ctrl->regs + HWSTATUS_MASK);
> > > >> > 	writel_relaxed(INT_MASK, ctrl->regs + ISR);    
> > > >>
> > > >> If we do a controller reset, there is much more state than that which
> > > >> needs to be restored. A lot of it is not readily available currently
> > > >> (timing, ECC settings...)    
> > > > 
> > > > This is actually a good test to detect what is not properly initialized
> > > > by the driver. Timings should be configured correctly through    
> > > > ->setup_data_interface(). ECC engine should be disabled by default and    
> > > > only enabled when ->{read,write}_page() is called.
> > > >     
> > > 
> > > Is setup_data_interface guaranteed to be called after a failed  
> > > ->exec_op()/{read,write}_page()?  
> > 
> > No. Maybe I misunderstood when tegra_nand_controller_reset() was
> > supposed to be called. That's something I would call only once, early
> > in the probe function, so that the controller is placed in a well-known
> > state before we start using it. Definitely not something you should
> > call after each error.  
> 
> Note that if you really want to reset the controller after an error,
> you should also iterate over all chips and call nand_reset() on them.

And that's clearly not possible to call nand_reset() from ->exec_op(),
otherwise you might recurse indefinitely in ->exec_op() if it keeps
failing, because nand_reset() relies on ->exec_op() to reset the chip.
So, as you said initially, not a good idea to reset the controller in
this case. But maybe you can clear the interrupts, mask them and cancel
the current operation (if any).
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On Fri,  1 Jun 2018 00:16:35 +0200
Stefan Agner <stefan@agner.ch> wrote:

> +
> +static int tegra_nand_chips_init(struct device *dev,
> +				 struct tegra_nand_controller *ctrl)
> +{
> +	struct device_node *np = dev->of_node;
> +	struct device_node *np_nand;
> +	int nchips = of_get_child_count(np);
> +	struct tegra_nand_chip *nand;
> +	struct mtd_info *mtd;
> +	struct nand_chip *chip;
> +	unsigned long config, bch_config = 0;
> +	int bits_per_step;
> +	int ret;
> +
> +	if (nchips != 1) {
> +		dev_err(dev, "Currently only one NAND chip supported\n");
> +		return -EINVAL;
> +	}
> +
> +	np_nand = of_get_next_child(np, NULL);
> +
> +	nand = devm_kzalloc(dev, sizeof(*nand), GFP_KERNEL);
> +	if (!nand)
> +		return -ENOMEM;
> +
> +	nand->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_LOW);
> +
> +	if (IS_ERR(nand->wp_gpio)) {
> +		ret = PTR_ERR(nand->wp_gpio);
> +		dev_err(dev, "Failed to request WP GPIO: %d\n", ret);
> +		return ret;
> +	}
> +

You should retrieve the value of reg and store it somewhere in
tegra_nand_chip. ->select_chip() is passed a chip_CE id, and it has to
be converted into a ctrl_CE id. Right now you're assuming that ctrl_CE0
always drives chip_CE0, but that's not necessarily the case.

Also, you don't support multi-CE chips, so you should check the number
of entries in reg and fail if it's not 1.
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On Saturday, 9 June 2018 00:51:01 MSK Stefan Agner wrote:
> On 01.06.2018 11:20, Dmitry Osipenko wrote:
> > On 01.06.2018 01:16, Stefan Agner wrote:
> >> Add support for the NAND flash controller found on NVIDIA
> >> Tegra 2 SoCs. This implementation does not make use of the
> >> command queue feature. Regular operations/data transfers are
> >> done in PIO mode. Page read/writes with hardware ECC make
> >> use of the DMA for data transfer.
> >> 
> >> Signed-off-by: Lucas Stach <dev@lynxeye.de>
> >> Signed-off-by: Stefan Agner <stefan@agner.ch>
> >> ---
> >> 
> >>  MAINTAINERS                       |    7 +
> >>  drivers/mtd/nand/raw/Kconfig      |    6 +
> >>  drivers/mtd/nand/raw/Makefile     |    1 +
> >>  drivers/mtd/nand/raw/tegra_nand.c | 1143 +++++++++++++++++++++++++++++
> >>  4 files changed, 1157 insertions(+)
> >>  create mode 100644 drivers/mtd/nand/raw/tegra_nand.c
> >> 
> >> diff --git a/MAINTAINERS b/MAINTAINERS
> >> index 58b9861ccf99..c2e5571c85d4 100644
> >> --- a/MAINTAINERS
> >> +++ b/MAINTAINERS
> >> @@ -13844,6 +13844,13 @@ M:	Laxman Dewangan <ldewangan@nvidia.com>
> >> 
> >>  S:	Supported
> >>  F:	drivers/input/keyboard/tegra-kbc.c
> >> 
> >> +TEGRA NAND DRIVER
> >> +M:	Stefan Agner <stefan@agner.ch>
> >> +M:	Lucas Stach <dev@lynxeye.de>
> >> +S:	Maintained
> >> +F:	Documentation/devicetree/bindings/mtd/nvidia-tegra20-nand.txt
> >> +F:	drivers/mtd/nand/raw/tegra_nand.c
> >> +
> >> 
> >>  TEGRA PWM DRIVER
> >>  M:	Thierry Reding <thierry.reding@gmail.com>
> >>  S:	Supported
> >> 
> >> diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
> >> index 19a2b283fbbe..e9093f52371e 100644
> >> --- a/drivers/mtd/nand/raw/Kconfig
> >> +++ b/drivers/mtd/nand/raw/Kconfig
> >> @@ -534,4 +534,10 @@ config MTD_NAND_MTK
> >> 
> >>  	  Enables support for NAND controller on MTK SoCs.
> >>  	  This controller is found on mt27xx, mt81xx, mt65xx SoCs.
> >> 
> >> +config MTD_NAND_TEGRA
> >> +	tristate "Support for NAND controller on NVIDIA Tegra"
> >> +	depends on ARCH_TEGRA || COMPILE_TEST
> >> +	help
> >> +	  Enables support for NAND flash controller on NVIDIA Tegra SoC.
> >> +
> >> 
> >>  endif # MTD_NAND
> >> 
> >> diff --git a/drivers/mtd/nand/raw/Makefile
> >> b/drivers/mtd/nand/raw/Makefile
> >> index 165b7ef9e9a1..d5a5f9832b88 100644
> >> --- a/drivers/mtd/nand/raw/Makefile
> >> +++ b/drivers/mtd/nand/raw/Makefile
> >> @@ -56,6 +56,7 @@ obj-$(CONFIG_MTD_NAND_HISI504)	        +=
> >> hisi504_nand.o
> >> 
> >>  obj-$(CONFIG_MTD_NAND_BRCMNAND)		+= brcmnand/
> >>  obj-$(CONFIG_MTD_NAND_QCOM)		+= qcom_nandc.o
> >>  obj-$(CONFIG_MTD_NAND_MTK)		+= mtk_ecc.o mtk_nand.o
> >> 
> >> +obj-$(CONFIG_MTD_NAND_TEGRA)		+= tegra_nand.o
> >> 
> >>  nand-objs := nand_base.o nand_bbt.o nand_timings.o nand_ids.o
> >>  nand-objs += nand_amd.o
> >> 
> >> diff --git a/drivers/mtd/nand/raw/tegra_nand.c
> >> b/drivers/mtd/nand/raw/tegra_nand.c new file mode 100644
> >> index 000000000000..e9664f2938a3
> >> --- /dev/null
> >> +++ b/drivers/mtd/nand/raw/tegra_nand.c
> >> @@ -0,0 +1,1143 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +/*
> >> + * Copyright (C) 2018 Stefan Agner <stefan@agner.ch>
> >> + * Copyright (C) 2014-2015 Lucas Stach <dev@lynxeye.de>
> >> + * Copyright (C) 2012 Avionic Design GmbH
> >> + */
> >> +
> >> +#include <linux/clk.h>
> >> +#include <linux/completion.h>
> >> +#include <linux/delay.h>
> >> +#include <linux/dma-mapping.h>
> >> +#include <linux/err.h>
> >> +#include <linux/gpio/consumer.h>
> >> +#include <linux/interrupt.h>
> >> +#include <linux/io.h>
> >> +#include <linux/module.h>
> >> +#include <linux/mtd/partitions.h>
> >> +#include <linux/mtd/rawnand.h>
> >> +#include <linux/of.h>
> >> +#include <linux/platform_device.h>
> >> +#include <linux/reset.h>
> >> +
> >> +#define CMD					0x00
> >> +#define   CMD_GO				BIT(31)
> >> +#define   CMD_CLE				BIT(30)
> >> +#define   CMD_ALE				BIT(29)
> >> +#define   CMD_PIO				BIT(28)
> >> +#define   CMD_TX				BIT(27)
> >> +#define   CMD_RX				BIT(26)
> >> +#define   CMD_SEC_CMD				BIT(25)
> >> +#define   CMD_AFT_DAT				BIT(24)
> >> +#define   CMD_TRANS_SIZE(x)			(((x - 1) & 0xf) << 20)
> >> +#define   CMD_A_VALID				BIT(19)
> >> +#define   CMD_B_VALID				BIT(18)
> >> +#define   CMD_RD_STATUS_CHK			BIT(17)
> >> +#define   CMD_RBSY_CHK				BIT(16)
> >> +#define   CMD_CE(x)				BIT((8 + ((x) & 0x7)))
> >> +#define   CMD_CLE_SIZE(x)			(((x - 1) & 0x3) << 4)
> >> +#define   CMD_ALE_SIZE(x)			(((x - 1) & 0xf) << 0)
> >> +
> >> +#define STATUS					0x04
> >> +
> >> +#define ISR					0x08
> >> +#define   ISR_CORRFAIL_ERR			BIT(24)
> >> +#define   ISR_UND				BIT(7)
> >> +#define   ISR_OVR				BIT(6)
> >> +#define   ISR_CMD_DONE				BIT(5)
> >> +#define   ISR_ECC_ERR				BIT(4)
> >> +
> >> +#define IER					0x0c
> >> +#define   IER_ERR_TRIG_VAL(x)			(((x) & 0xf) << 16)
> >> +#define   IER_UND				BIT(7)
> >> +#define   IER_OVR				BIT(6)
> >> +#define   IER_CMD_DONE				BIT(5)
> >> +#define   IER_ECC_ERR				BIT(4)
> >> +#define   IER_GIE				BIT(0)
> >> +
> >> +#define CFG					0x10
> >> +#define   CFG_HW_ECC				BIT(31)
> >> +#define   CFG_ECC_SEL				BIT(30)
> >> +#define   CFG_ERR_COR				BIT(29)
> >> +#define   CFG_PIPE_EN				BIT(28)
> >> +#define   CFG_TVAL_4				(0 << 24)
> >> +#define   CFG_TVAL_6				(1 << 24)
> >> +#define   CFG_TVAL_8				(2 << 24)
> >> +#define   CFG_SKIP_SPARE			BIT(23)
> >> +#define   CFG_BUS_WIDTH_16			BIT(21)
> >> +#define   CFG_COM_BSY				BIT(20)
> >> +#define   CFG_PS_256				(0 << 16)
> >> +#define   CFG_PS_512				(1 << 16)
> >> +#define   CFG_PS_1024				(2 << 16)
> >> +#define   CFG_PS_2048				(3 << 16)
> >> +#define   CFG_PS_4096				(4 << 16)
> >> +#define   CFG_SKIP_SPARE_SIZE_4			(0 << 14)
> >> +#define   CFG_SKIP_SPARE_SIZE_8			(1 << 14)
> >> +#define   CFG_SKIP_SPARE_SIZE_12		(2 << 14)
> >> +#define   CFG_SKIP_SPARE_SIZE_16		(3 << 14)
> >> +#define   CFG_TAG_BYTE_SIZE(x)			((x) & 0xff)
> >> +
> >> +#define TIMING_1				0x14
> >> +#define   TIMING_TRP_RESP(x)			(((x) & 0xf) << 28)
> >> +#define   TIMING_TWB(x)				(((x) & 0xf) << 24)
> >> +#define   TIMING_TCR_TAR_TRR(x)			(((x) & 0xf) << 20)
> >> +#define   TIMING_TWHR(x)			(((x) & 0xf) << 16)
> >> +#define   TIMING_TCS(x)				(((x) & 0x3) << 14)
> >> +#define   TIMING_TWH(x)				(((x) & 0x3) << 12)
> >> +#define   TIMING_TWP(x)				(((x) & 0xf) <<  8)
> >> +#define   TIMING_TRH(x)				(((x) & 0x3) <<  4)
> >> +#define   TIMING_TRP(x)				(((x) & 0xf) <<  0)
> >> +
> >> +#define RESP					0x18
> >> +
> >> +#define TIMING_2				0x1c
> >> +#define   TIMING_TADL(x)			((x) & 0xf)
> >> +
> >> +#define CMD_1					0x20
> >> +#define CMD_2					0x24
> >> +#define ADDR_1					0x28
> >> +#define ADDR_2					0x2c
> >> +
> >> +#define DMA_CTRL				0x30
> >> +#define   DMA_CTRL_GO				BIT(31)
> >> +#define   DMA_CTRL_IN				(0 << 30)
> >> +#define   DMA_CTRL_OUT				BIT(30)
> >> +#define   DMA_CTRL_PERF_EN			BIT(29)
> >> +#define   DMA_CTRL_IE_DONE			BIT(28)
> >> +#define   DMA_CTRL_REUSE			BIT(27)
> >> +#define   DMA_CTRL_BURST_1			(2 << 24)
> >> +#define   DMA_CTRL_BURST_4			(3 << 24)
> >> +#define   DMA_CTRL_BURST_8			(4 << 24)
> >> +#define   DMA_CTRL_BURST_16			(5 << 24)
> >> +#define   DMA_CTRL_IS_DONE			BIT(20)
> >> +#define   DMA_CTRL_EN_A				BIT(2)
> >> +#define   DMA_CTRL_EN_B				BIT(1)
> >> +
> >> +#define DMA_CFG_A				0x34
> >> +#define DMA_CFG_B				0x38
> >> +
> >> +#define FIFO_CTRL				0x3c
> >> +#define   FIFO_CTRL_CLR_ALL			BIT(3)
> >> +
> >> +#define DATA_PTR				0x40
> >> +#define TAG_PTR					0x44
> >> +#define ECC_PTR					0x48
> >> +
> >> +#define DEC_STATUS				0x4c
> >> +#define   DEC_STATUS_A_ECC_FAIL			BIT(1)
> >> +#define   DEC_STATUS_ERR_COUNT_MASK		0x00ff0000
> >> +#define   DEC_STATUS_ERR_COUNT_SHIFT		16
> >> +
> >> +#define HWSTATUS_CMD				0x50
> >> +#define HWSTATUS_MASK				0x54
> >> +#define   HWSTATUS_RDSTATUS_MASK(x)		(((x) & 0xff) << 24)
> >> +#define   HWSTATUS_RDSTATUS_VALUE(x)		(((x) & 0xff) << 16)
> >> +#define   HWSTATUS_RBSY_MASK(x)			(((x) & 0xff) << 8)
> >> +#define   HWSTATUS_RBSY_VALUE(x)		(((x) & 0xff) << 0)
> >> +
> >> +#define BCH_CONFIG				0xcc
> >> +#define   BCH_ENABLE				BIT(0)
> >> +#define   BCH_TVAL_4				(0 << 4)
> >> +#define   BCH_TVAL_8				(1 << 4)
> >> +#define   BCH_TVAL_14				(2 << 4)
> >> +#define   BCH_TVAL_16				(3 << 4)
> >> +
> >> +#define DEC_STAT_RESULT				0xd0
> >> +#define DEC_STAT_BUF				0xd4
> >> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_MASK	0xff000000
> >> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_SHIFT	24
> >> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_MASK	0x00ff0000
> >> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT	16
> >> +#define   DEC_STAT_BUF_MAX_CORR_CNT_MASK	0x00001f00
> >> +#define   DEC_STAT_BUF_MAX_CORR_CNT_SHIFT	8
> >> +
> >> +#define OFFSET(val, off)		((val) < (off) ? 0 : (val) - (off))
> >> +
> >> +#define SKIP_SPARE_BYTES	4
> >> +#define BITS_PER_STEP_RS	18
> >> +#define BITS_PER_STEP_BCH	13
> >> +
> >> +struct tegra_nand_controller {
> >> +	struct nand_hw_control controller;
> >> +	void __iomem *regs;
> >> +	struct clk *clk;
> >> +	struct device *dev;
> >> +	struct completion command_complete;
> >> +	struct completion dma_complete;
> >> +	bool last_read_error;
> >> +	int cur_chip;
> >> +	struct nand_chip *chip;
> >> +};
> >> +
> >> +struct tegra_nand_chip {
> >> +	struct nand_chip chip;
> >> +	struct gpio_desc *wp_gpio;
> >> +	struct mtd_oob_region tag;
> >> +};
> >> +
> >> +static inline struct tegra_nand_controller *to_tegra_ctrl(
> >> +						struct nand_hw_control *hw_ctrl)
> >> +{
> >> +	return container_of(hw_ctrl, struct tegra_nand_controller, 
controller);
> >> +}
> >> +
> >> +static inline struct tegra_nand_chip *to_tegra_chip(struct nand_chip
> >> *chip) +{
> >> +	return container_of(chip, struct tegra_nand_chip, chip);
> >> +}
> >> +
> >> +static int tegra_nand_ooblayout_rs_ecc(struct mtd_info *mtd, int
> >> section,
> >> +				       struct mtd_oob_region *oobregion)
> >> +{
> >> +	struct nand_chip *chip = mtd_to_nand(mtd);
> >> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS *
> >> chip->ecc.strength,
> >> +					  BITS_PER_BYTE);
> >> +
> >> +	if (section > 0)
> >> +		return -ERANGE;
> >> +
> >> +	oobregion->offset = SKIP_SPARE_BYTES;
> >> +	oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 4);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int tegra_nand_ooblayout_rs_free(struct mtd_info *mtd, int
> >> section,
> >> +					struct mtd_oob_region *oobregion)
> >> +{
> >> +	struct nand_chip *chip = mtd_to_nand(mtd);
> >> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS *
> >> chip->ecc.strength,
> >> +					  BITS_PER_BYTE);
> >> +
> >> +	if (section > 0)
> >> +		return -ERANGE;
> >> +
> >> +	oobregion->offset = SKIP_SPARE_BYTES +
> >> +			    round_up(bytes_per_step * chip->ecc.steps, 4);
> >> +	oobregion->length = mtd->oobsize - oobregion->offset;
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static const struct mtd_ooblayout_ops tegra_nand_oob_rs_ops = {
> >> +	.ecc = tegra_nand_ooblayout_rs_ecc,
> >> +	.free = tegra_nand_ooblayout_rs_free,
> >> +};
> >> +
> >> +static int tegra_nand_ooblayout_bch_ecc(struct mtd_info *mtd, int
> >> section,
> >> +				       struct mtd_oob_region *oobregion)
> >> +{
> >> +	struct nand_chip *chip = mtd_to_nand(mtd);
> >> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH *
> >> chip->ecc.strength,
> >> +					  BITS_PER_BYTE);
> >> +
> >> +	if (section > 0)
> >> +		return -ERANGE;
> >> +
> >> +	oobregion->offset = SKIP_SPARE_BYTES;
> >> +	oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 4);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int tegra_nand_ooblayout_bch_free(struct mtd_info *mtd, int
> >> section, +					struct mtd_oob_region *oobregion)
> >> +{
> >> +	struct nand_chip *chip = mtd_to_nand(mtd);
> >> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH *
> >> chip->ecc.strength,
> >> +					  BITS_PER_BYTE);
> >> +
> >> +	if (section > 0)
> >> +		return -ERANGE;
> >> +
> >> +	oobregion->offset = SKIP_SPARE_BYTES +
> >> +			    round_up(bytes_per_step * chip->ecc.steps, 4);
> >> +	oobregion->length = mtd->oobsize - oobregion->offset;
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +/*
> >> + * Layout with tag bytes is
> >> + *
> >> + *
> >> ------------------------------------------------------------------------
> >> -- + * | main area                       | skip bytes | tag bytes |
> >> parity | .. | + *
> >> ------------------------------------------------------------------------
> >> -- + *
> >> + * If not tag bytes are written, parity moves right after skip bytes!
> >> + */
> >> +static const struct mtd_ooblayout_ops tegra_nand_oob_bch_ops = {
> >> +	.ecc = tegra_nand_ooblayout_bch_ecc,
> >> +	.free = tegra_nand_ooblayout_bch_free,
> >> +};
> >> +
> >> +static irqreturn_t tegra_nand_irq(int irq, void *data)
> >> +{
> >> +	struct tegra_nand_controller *ctrl = data;
> >> +	u32 isr, dma;
> >> +
> >> +	isr = readl_relaxed(ctrl->regs + ISR);
> >> +	dma = readl_relaxed(ctrl->regs + DMA_CTRL);
> >> +	dev_dbg(ctrl->dev, "isr %08x\n", isr);
> >> +
> >> +	if (!isr && !(dma & DMA_CTRL_IS_DONE))
> >> +		return IRQ_NONE;
> >> +
> >> +	/*
> >> +	 * The bit name is somewhat missleading: This is also set when
> >> +	 * HW ECC was successful. The data sheet states:
> >> +	 * Correctable OR Un-correctable errors occurred in the DMA 
transfer...
> >> +	 */
> >> +	if (isr & ISR_CORRFAIL_ERR)
> >> +		ctrl->last_read_error = true;
> >> +
> >> +	if (isr & ISR_CMD_DONE)
> >> +		complete(&ctrl->command_complete);
> >> +
> >> +	if (isr & ISR_UND)
> >> +		dev_err(ctrl->dev, "FIFO underrun\n");
> >> +
> >> +	if (isr & ISR_OVR)
> >> +		dev_err(ctrl->dev, "FIFO overrun\n");
> >> +
> >> +	/* handle DMA interrupts */
> >> +	if (dma & DMA_CTRL_IS_DONE) {
> >> +		writel_relaxed(dma, ctrl->regs + DMA_CTRL);
> >> +		complete(&ctrl->dma_complete);
> >> +	}
> >> +
> >> +	/* clear interrupts */
> >> +	writel_relaxed(isr, ctrl->regs + ISR);
> >> +
> >> +	return IRQ_HANDLED;
> >> +}
> >> +
> >> +static const char * const tegra_nand_reg_names[] = {
> >> +	"COMMAND",
> >> +	"STATUS",
> >> +	"ISR",
> >> +	"IER",
> >> +	"CONFIG",
> >> +	"TIMING",
> >> +	NULL,
> >> +	"TIMING2",
> >> +	"CMD_REG1",
> >> +	"CMD_REG2",
> >> +	"ADDR_REG1",
> >> +	"ADDR_REG2",
> >> +	"DMA_MST_CTRL",
> >> +	"DMA_CFG_A",
> >> +	"DMA_CFG_B",
> >> +	"FIFO_CTRL",
> >> +};
> >> +
> >> +static void tegra_nand_dump_reg(struct tegra_nand_controller *ctrl)
> >> +{
> >> +	u32 reg;
> >> +	int i;
> >> +
> >> +	dev_err(ctrl->dev, "Tegra NAND controller register dump\n");
> >> +	for (i = 0; i < ARRAY_SIZE(tegra_nand_reg_names); i++) {
> >> +		const char *reg_name = tegra_nand_reg_names[i];
> >> +
> >> +		if (!reg_name)
> >> +			continue;
> >> +
> >> +		reg = readl_relaxed(ctrl->regs + (i * 4));
> >> +		dev_err(ctrl->dev, "%s: 0x%08x\n", reg_name, reg);
> >> +	}
> >> +}
> >> +
> >> +static int tegra_nand_cmd(struct nand_chip *chip,
> >> +			 const struct nand_subop *subop)
> >> +{
> >> +	const struct nand_op_instr *instr;
> >> +	const struct nand_op_instr *instr_data_in = NULL;
> >> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
> >> +	unsigned int op_id, size = 0, offset = 0;
> >> +	bool first_cmd = true;
> >> +	u32 reg, cmd = 0;
> >> +	int ret;
> >> +
> >> +	for (op_id = 0; op_id < subop->ninstrs; op_id++) {
> >> +		unsigned int naddrs, i;
> >> +		const u8 *addrs;
> >> +		u32 addr1 = 0, addr2 = 0;
> >> +
> >> +		instr = &subop->instrs[op_id];
> >> +
> >> +		switch (instr->type) {
> >> +		case NAND_OP_CMD_INSTR:
> >> +			if (first_cmd) {
> >> +				cmd |= CMD_CLE;
> >> +				writel_relaxed(instr->ctx.cmd.opcode,
> >> +					       ctrl->regs + CMD_1);
> >> +			} else {
> >> +				cmd |= CMD_SEC_CMD;
> >> +				writel_relaxed(instr->ctx.cmd.opcode,
> >> +					       ctrl->regs + CMD_2);
> >> +			}
> >> +			first_cmd = false;
> >> +			break;
> >> +		case NAND_OP_ADDR_INSTR:
> >> +			offset = nand_subop_get_addr_start_off(subop, op_id);
> >> +			naddrs = nand_subop_get_num_addr_cyc(subop, op_id);
> >> +			addrs = &instr->ctx.addr.addrs[offset];
> >> +
> >> +			cmd |= CMD_ALE | CMD_ALE_SIZE(naddrs);
> >> +			for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
> >> +				addr1 |= *addrs++ << (BITS_PER_BYTE * i);
> >> +			naddrs -= i;
> >> +			for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
> >> +				addr2 |= *addrs++ << (BITS_PER_BYTE * i);
> >> +			writel_relaxed(addr1, ctrl->regs + ADDR_1);
> >> +			writel_relaxed(addr2, ctrl->regs + ADDR_2);
> >> +			break;
> >> +
> >> +		case NAND_OP_DATA_IN_INSTR:
> >> +			size = nand_subop_get_data_len(subop, op_id);
> >> +			offset = nand_subop_get_data_start_off(subop, op_id);
> >> +
> >> +			cmd |= CMD_TRANS_SIZE(size) | CMD_PIO | CMD_RX |
> >> +				CMD_A_VALID;
> >> +
> >> +			instr_data_in = instr;
> >> +			break;
> >> +
> >> +		case NAND_OP_DATA_OUT_INSTR:
> >> +			size = nand_subop_get_data_len(subop, op_id);
> >> +			offset = nand_subop_get_data_start_off(subop, op_id);
> >> +
> >> +			cmd |= CMD_TRANS_SIZE(size) | CMD_PIO | CMD_TX |
> >> +				CMD_A_VALID;
> >> +
> >> +			memcpy(&reg, instr->ctx.data.buf.out + offset, size);
> >> +			writel_relaxed(reg, ctrl->regs + RESP);
> >> +
> >> +			break;
> >> +		case NAND_OP_WAITRDY_INSTR:
> >> +			cmd |= CMD_RBSY_CHK;
> >> +			break;
> >> +
> >> +		}
> >> +	}
> >> +
> >> +	cmd |= CMD_GO | CMD_CE(ctrl->cur_chip);
> >> +	writel_relaxed(cmd, ctrl->regs + CMD);
> >> +	ret = wait_for_completion_timeout(&ctrl->command_complete,
> >> +					  msecs_to_jiffies(500));
> >> +	if (!ret) {
> >> +		dev_err(ctrl->dev, "CMD timeout\n");
> >> +		tegra_nand_dump_reg(ctrl);
> >> +		return -ETIMEDOUT;
> >> +	}
> > 
> > - wait_for_completion_timeout() could fail
> 
> Not according to:
> https://elixir.bootlin.com/linux/latest/source/kernel/sched/completion.c#L14
> 0 https://www.kernel.org/doc/Documentation/scheduler/completion.txt
> 
> Afaik, only the _interruptible variant can fail.

Okay.

> Btw, maybe we should use the _io variant?

Looks like the _io variant is something specific to block/FS subsys and 
shouldn't be used by the drivers.

> > - HW shall be reset
> > - completion shall be re-inited because IRQ could fire just after the
> > completion timeout
> > 
> > I'd write it something like this:
> > 
> > #define INT_MASK	(IER_UND | IER_OVR | IER_CMD_DONE | IER_GIE)
> > 
> > #define HWSTATUS_MASK	(HWSTATUS_RDSTATUS_MASK(1) |		 \
> > 
> > 			 HWSTATUS_RDSTATUS_VALUE(0) |		 \
> > 			 HWSTATUS_RBSY_MASK(NAND_STATUS_READY) | \
> > 			 HWSTATUS_RBSY_VALUE(NAND_STATUS_READY))
> > 
> > #define HW_TIMEOUT	500
> > 
> > void tegra_nand_controller_reset(struct tegra_nand_controller *ctrl)
> > {
> > 
> > 	int err;
> > 	
> > 	disable_irq(ctrl->irq);
> > 	
> > 	err = reset_control_reset(ctrl->rst);
> > 	if (err) {
> > 	
> > 		dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
> > 		msleep(HW_TIMEOUT);
> > 	
> > 	}
> > 	
> > 	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
> > 	writel_relaxed(HWSTATUS_MASK, ctrl->regs + HWSTATUS_MASK);
> > 	writel_relaxed(INT_MASK, ctrl->regs + ISR);
> 
> If we do a controller reset, there is much more state than that which
> needs to be restored. A lot of it is not readily available currently
> (timing, ECC settings...)
> 
> That seems a lot of work for a code path I do not intend to ever use :-)

Are you sure that resetting HW resets the timing and other registers 
configuration? Reset implementation is HW-specific, like for example in a case 
of a video decoder the registers state is re-intialized on HW reset, but 
registers configuration is untouched in a case of resetting GPU. I'd suggest 
to check whether NAND controller resetting affects the HW configuration.


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On 09.06.2018 14:21, Dmitry Osipenko wrote:
> On Saturday, 9 June 2018 00:51:01 MSK Stefan Agner wrote:
>> On 01.06.2018 11:20, Dmitry Osipenko wrote:
>> > On 01.06.2018 01:16, Stefan Agner wrote:
>> >> Add support for the NAND flash controller found on NVIDIA
>> >> Tegra 2 SoCs. This implementation does not make use of the
>> >> command queue feature. Regular operations/data transfers are
>> >> done in PIO mode. Page read/writes with hardware ECC make
>> >> use of the DMA for data transfer.
>> >>
>> >> Signed-off-by: Lucas Stach <dev@lynxeye.de>
>> >> Signed-off-by: Stefan Agner <stefan@agner.ch>
>> >> ---
>> >>
>> >>  MAINTAINERS                       |    7 +
>> >>  drivers/mtd/nand/raw/Kconfig      |    6 +
>> >>  drivers/mtd/nand/raw/Makefile     |    1 +
>> >>  drivers/mtd/nand/raw/tegra_nand.c | 1143 +++++++++++++++++++++++++++++
>> >>  4 files changed, 1157 insertions(+)
>> >>  create mode 100644 drivers/mtd/nand/raw/tegra_nand.c
>> >>
>> >> diff --git a/MAINTAINERS b/MAINTAINERS
>> >> index 58b9861ccf99..c2e5571c85d4 100644
>> >> --- a/MAINTAINERS
>> >> +++ b/MAINTAINERS
>> >> @@ -13844,6 +13844,13 @@ M:	Laxman Dewangan <ldewangan@nvidia.com>
>> >>
>> >>  S:	Supported
>> >>  F:	drivers/input/keyboard/tegra-kbc.c
>> >>
>> >> +TEGRA NAND DRIVER
>> >> +M:	Stefan Agner <stefan@agner.ch>
>> >> +M:	Lucas Stach <dev@lynxeye.de>
>> >> +S:	Maintained
>> >> +F:	Documentation/devicetree/bindings/mtd/nvidia-tegra20-nand.txt
>> >> +F:	drivers/mtd/nand/raw/tegra_nand.c
>> >> +
>> >>
>> >>  TEGRA PWM DRIVER
>> >>  M:	Thierry Reding <thierry.reding@gmail.com>
>> >>  S:	Supported
>> >>
>> >> diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
>> >> index 19a2b283fbbe..e9093f52371e 100644
>> >> --- a/drivers/mtd/nand/raw/Kconfig
>> >> +++ b/drivers/mtd/nand/raw/Kconfig
>> >> @@ -534,4 +534,10 @@ config MTD_NAND_MTK
>> >>
>> >>  	  Enables support for NAND controller on MTK SoCs.
>> >>  	  This controller is found on mt27xx, mt81xx, mt65xx SoCs.
>> >>
>> >> +config MTD_NAND_TEGRA
>> >> +	tristate "Support for NAND controller on NVIDIA Tegra"
>> >> +	depends on ARCH_TEGRA || COMPILE_TEST
>> >> +	help
>> >> +	  Enables support for NAND flash controller on NVIDIA Tegra SoC.
>> >> +
>> >>
>> >>  endif # MTD_NAND
>> >>
>> >> diff --git a/drivers/mtd/nand/raw/Makefile
>> >> b/drivers/mtd/nand/raw/Makefile
>> >> index 165b7ef9e9a1..d5a5f9832b88 100644
>> >> --- a/drivers/mtd/nand/raw/Makefile
>> >> +++ b/drivers/mtd/nand/raw/Makefile
>> >> @@ -56,6 +56,7 @@ obj-$(CONFIG_MTD_NAND_HISI504)	        +=
>> >> hisi504_nand.o
>> >>
>> >>  obj-$(CONFIG_MTD_NAND_BRCMNAND)		+= brcmnand/
>> >>  obj-$(CONFIG_MTD_NAND_QCOM)		+= qcom_nandc.o
>> >>  obj-$(CONFIG_MTD_NAND_MTK)		+= mtk_ecc.o mtk_nand.o
>> >>
>> >> +obj-$(CONFIG_MTD_NAND_TEGRA)		+= tegra_nand.o
>> >>
>> >>  nand-objs := nand_base.o nand_bbt.o nand_timings.o nand_ids.o
>> >>  nand-objs += nand_amd.o
>> >>
>> >> diff --git a/drivers/mtd/nand/raw/tegra_nand.c
>> >> b/drivers/mtd/nand/raw/tegra_nand.c new file mode 100644
>> >> index 000000000000..e9664f2938a3
>> >> --- /dev/null
>> >> +++ b/drivers/mtd/nand/raw/tegra_nand.c
>> >> @@ -0,0 +1,1143 @@
>> >> +// SPDX-License-Identifier: GPL-2.0
>> >> +/*
>> >> + * Copyright (C) 2018 Stefan Agner <stefan@agner.ch>
>> >> + * Copyright (C) 2014-2015 Lucas Stach <dev@lynxeye.de>
>> >> + * Copyright (C) 2012 Avionic Design GmbH
>> >> + */
>> >> +
>> >> +#include <linux/clk.h>
>> >> +#include <linux/completion.h>
>> >> +#include <linux/delay.h>
>> >> +#include <linux/dma-mapping.h>
>> >> +#include <linux/err.h>
>> >> +#include <linux/gpio/consumer.h>
>> >> +#include <linux/interrupt.h>
>> >> +#include <linux/io.h>
>> >> +#include <linux/module.h>
>> >> +#include <linux/mtd/partitions.h>
>> >> +#include <linux/mtd/rawnand.h>
>> >> +#include <linux/of.h>
>> >> +#include <linux/platform_device.h>
>> >> +#include <linux/reset.h>
>> >> +
>> >> +#define CMD					0x00
>> >> +#define   CMD_GO				BIT(31)
>> >> +#define   CMD_CLE				BIT(30)
>> >> +#define   CMD_ALE				BIT(29)
>> >> +#define   CMD_PIO				BIT(28)
>> >> +#define   CMD_TX				BIT(27)
>> >> +#define   CMD_RX				BIT(26)
>> >> +#define   CMD_SEC_CMD				BIT(25)
>> >> +#define   CMD_AFT_DAT				BIT(24)
>> >> +#define   CMD_TRANS_SIZE(x)			(((x - 1) & 0xf) << 20)
>> >> +#define   CMD_A_VALID				BIT(19)
>> >> +#define   CMD_B_VALID				BIT(18)
>> >> +#define   CMD_RD_STATUS_CHK			BIT(17)
>> >> +#define   CMD_RBSY_CHK				BIT(16)
>> >> +#define   CMD_CE(x)				BIT((8 + ((x) & 0x7)))
>> >> +#define   CMD_CLE_SIZE(x)			(((x - 1) & 0x3) << 4)
>> >> +#define   CMD_ALE_SIZE(x)			(((x - 1) & 0xf) << 0)
>> >> +
>> >> +#define STATUS					0x04
>> >> +
>> >> +#define ISR					0x08
>> >> +#define   ISR_CORRFAIL_ERR			BIT(24)
>> >> +#define   ISR_UND				BIT(7)
>> >> +#define   ISR_OVR				BIT(6)
>> >> +#define   ISR_CMD_DONE				BIT(5)
>> >> +#define   ISR_ECC_ERR				BIT(4)
>> >> +
>> >> +#define IER					0x0c
>> >> +#define   IER_ERR_TRIG_VAL(x)			(((x) & 0xf) << 16)
>> >> +#define   IER_UND				BIT(7)
>> >> +#define   IER_OVR				BIT(6)
>> >> +#define   IER_CMD_DONE				BIT(5)
>> >> +#define   IER_ECC_ERR				BIT(4)
>> >> +#define   IER_GIE				BIT(0)
>> >> +
>> >> +#define CFG					0x10
>> >> +#define   CFG_HW_ECC				BIT(31)
>> >> +#define   CFG_ECC_SEL				BIT(30)
>> >> +#define   CFG_ERR_COR				BIT(29)
>> >> +#define   CFG_PIPE_EN				BIT(28)
>> >> +#define   CFG_TVAL_4				(0 << 24)
>> >> +#define   CFG_TVAL_6				(1 << 24)
>> >> +#define   CFG_TVAL_8				(2 << 24)
>> >> +#define   CFG_SKIP_SPARE			BIT(23)
>> >> +#define   CFG_BUS_WIDTH_16			BIT(21)
>> >> +#define   CFG_COM_BSY				BIT(20)
>> >> +#define   CFG_PS_256				(0 << 16)
>> >> +#define   CFG_PS_512				(1 << 16)
>> >> +#define   CFG_PS_1024				(2 << 16)
>> >> +#define   CFG_PS_2048				(3 << 16)
>> >> +#define   CFG_PS_4096				(4 << 16)
>> >> +#define   CFG_SKIP_SPARE_SIZE_4			(0 << 14)
>> >> +#define   CFG_SKIP_SPARE_SIZE_8			(1 << 14)
>> >> +#define   CFG_SKIP_SPARE_SIZE_12		(2 << 14)
>> >> +#define   CFG_SKIP_SPARE_SIZE_16		(3 << 14)
>> >> +#define   CFG_TAG_BYTE_SIZE(x)			((x) & 0xff)
>> >> +
>> >> +#define TIMING_1				0x14
>> >> +#define   TIMING_TRP_RESP(x)			(((x) & 0xf) << 28)
>> >> +#define   TIMING_TWB(x)				(((x) & 0xf) << 24)
>> >> +#define   TIMING_TCR_TAR_TRR(x)			(((x) & 0xf) << 20)
>> >> +#define   TIMING_TWHR(x)			(((x) & 0xf) << 16)
>> >> +#define   TIMING_TCS(x)				(((x) & 0x3) << 14)
>> >> +#define   TIMING_TWH(x)				(((x) & 0x3) << 12)
>> >> +#define   TIMING_TWP(x)				(((x) & 0xf) <<  8)
>> >> +#define   TIMING_TRH(x)				(((x) & 0x3) <<  4)
>> >> +#define   TIMING_TRP(x)				(((x) & 0xf) <<  0)
>> >> +
>> >> +#define RESP					0x18
>> >> +
>> >> +#define TIMING_2				0x1c
>> >> +#define   TIMING_TADL(x)			((x) & 0xf)
>> >> +
>> >> +#define CMD_1					0x20
>> >> +#define CMD_2					0x24
>> >> +#define ADDR_1					0x28
>> >> +#define ADDR_2					0x2c
>> >> +
>> >> +#define DMA_CTRL				0x30
>> >> +#define   DMA_CTRL_GO				BIT(31)
>> >> +#define   DMA_CTRL_IN				(0 << 30)
>> >> +#define   DMA_CTRL_OUT				BIT(30)
>> >> +#define   DMA_CTRL_PERF_EN			BIT(29)
>> >> +#define   DMA_CTRL_IE_DONE			BIT(28)
>> >> +#define   DMA_CTRL_REUSE			BIT(27)
>> >> +#define   DMA_CTRL_BURST_1			(2 << 24)
>> >> +#define   DMA_CTRL_BURST_4			(3 << 24)
>> >> +#define   DMA_CTRL_BURST_8			(4 << 24)
>> >> +#define   DMA_CTRL_BURST_16			(5 << 24)
>> >> +#define   DMA_CTRL_IS_DONE			BIT(20)
>> >> +#define   DMA_CTRL_EN_A				BIT(2)
>> >> +#define   DMA_CTRL_EN_B				BIT(1)
>> >> +
>> >> +#define DMA_CFG_A				0x34
>> >> +#define DMA_CFG_B				0x38
>> >> +
>> >> +#define FIFO_CTRL				0x3c
>> >> +#define   FIFO_CTRL_CLR_ALL			BIT(3)
>> >> +
>> >> +#define DATA_PTR				0x40
>> >> +#define TAG_PTR					0x44
>> >> +#define ECC_PTR					0x48
>> >> +
>> >> +#define DEC_STATUS				0x4c
>> >> +#define   DEC_STATUS_A_ECC_FAIL			BIT(1)
>> >> +#define   DEC_STATUS_ERR_COUNT_MASK		0x00ff0000
>> >> +#define   DEC_STATUS_ERR_COUNT_SHIFT		16
>> >> +
>> >> +#define HWSTATUS_CMD				0x50
>> >> +#define HWSTATUS_MASK				0x54
>> >> +#define   HWSTATUS_RDSTATUS_MASK(x)		(((x) & 0xff) << 24)
>> >> +#define   HWSTATUS_RDSTATUS_VALUE(x)		(((x) & 0xff) << 16)
>> >> +#define   HWSTATUS_RBSY_MASK(x)			(((x) & 0xff) << 8)
>> >> +#define   HWSTATUS_RBSY_VALUE(x)		(((x) & 0xff) << 0)
>> >> +
>> >> +#define BCH_CONFIG				0xcc
>> >> +#define   BCH_ENABLE				BIT(0)
>> >> +#define   BCH_TVAL_4				(0 << 4)
>> >> +#define   BCH_TVAL_8				(1 << 4)
>> >> +#define   BCH_TVAL_14				(2 << 4)
>> >> +#define   BCH_TVAL_16				(3 << 4)
>> >> +
>> >> +#define DEC_STAT_RESULT				0xd0
>> >> +#define DEC_STAT_BUF				0xd4
>> >> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_MASK	0xff000000
>> >> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_SHIFT	24
>> >> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_MASK	0x00ff0000
>> >> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT	16
>> >> +#define   DEC_STAT_BUF_MAX_CORR_CNT_MASK	0x00001f00
>> >> +#define   DEC_STAT_BUF_MAX_CORR_CNT_SHIFT	8
>> >> +
>> >> +#define OFFSET(val, off)		((val) < (off) ? 0 : (val) - (off))
>> >> +
>> >> +#define SKIP_SPARE_BYTES	4
>> >> +#define BITS_PER_STEP_RS	18
>> >> +#define BITS_PER_STEP_BCH	13
>> >> +
>> >> +struct tegra_nand_controller {
>> >> +	struct nand_hw_control controller;
>> >> +	void __iomem *regs;
>> >> +	struct clk *clk;
>> >> +	struct device *dev;
>> >> +	struct completion command_complete;
>> >> +	struct completion dma_complete;
>> >> +	bool last_read_error;
>> >> +	int cur_chip;
>> >> +	struct nand_chip *chip;
>> >> +};
>> >> +
>> >> +struct tegra_nand_chip {
>> >> +	struct nand_chip chip;
>> >> +	struct gpio_desc *wp_gpio;
>> >> +	struct mtd_oob_region tag;
>> >> +};
>> >> +
>> >> +static inline struct tegra_nand_controller *to_tegra_ctrl(
>> >> +						struct nand_hw_control *hw_ctrl)
>> >> +{
>> >> +	return container_of(hw_ctrl, struct tegra_nand_controller,
> controller);
>> >> +}
>> >> +
>> >> +static inline struct tegra_nand_chip *to_tegra_chip(struct nand_chip
>> >> *chip) +{
>> >> +	return container_of(chip, struct tegra_nand_chip, chip);
>> >> +}
>> >> +
>> >> +static int tegra_nand_ooblayout_rs_ecc(struct mtd_info *mtd, int
>> >> section,
>> >> +				       struct mtd_oob_region *oobregion)
>> >> +{
>> >> +	struct nand_chip *chip = mtd_to_nand(mtd);
>> >> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS *
>> >> chip->ecc.strength,
>> >> +					  BITS_PER_BYTE);
>> >> +
>> >> +	if (section > 0)
>> >> +		return -ERANGE;
>> >> +
>> >> +	oobregion->offset = SKIP_SPARE_BYTES;
>> >> +	oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 4);
>> >> +
>> >> +	return 0;
>> >> +}
>> >> +
>> >> +static int tegra_nand_ooblayout_rs_free(struct mtd_info *mtd, int
>> >> section,
>> >> +					struct mtd_oob_region *oobregion)
>> >> +{
>> >> +	struct nand_chip *chip = mtd_to_nand(mtd);
>> >> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS *
>> >> chip->ecc.strength,
>> >> +					  BITS_PER_BYTE);
>> >> +
>> >> +	if (section > 0)
>> >> +		return -ERANGE;
>> >> +
>> >> +	oobregion->offset = SKIP_SPARE_BYTES +
>> >> +			    round_up(bytes_per_step * chip->ecc.steps, 4);
>> >> +	oobregion->length = mtd->oobsize - oobregion->offset;
>> >> +
>> >> +	return 0;
>> >> +}
>> >> +
>> >> +static const struct mtd_ooblayout_ops tegra_nand_oob_rs_ops = {
>> >> +	.ecc = tegra_nand_ooblayout_rs_ecc,
>> >> +	.free = tegra_nand_ooblayout_rs_free,
>> >> +};
>> >> +
>> >> +static int tegra_nand_ooblayout_bch_ecc(struct mtd_info *mtd, int
>> >> section,
>> >> +				       struct mtd_oob_region *oobregion)
>> >> +{
>> >> +	struct nand_chip *chip = mtd_to_nand(mtd);
>> >> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH *
>> >> chip->ecc.strength,
>> >> +					  BITS_PER_BYTE);
>> >> +
>> >> +	if (section > 0)
>> >> +		return -ERANGE;
>> >> +
>> >> +	oobregion->offset = SKIP_SPARE_BYTES;
>> >> +	oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 4);
>> >> +
>> >> +	return 0;
>> >> +}
>> >> +
>> >> +static int tegra_nand_ooblayout_bch_free(struct mtd_info *mtd, int
>> >> section, +					struct mtd_oob_region *oobregion)
>> >> +{
>> >> +	struct nand_chip *chip = mtd_to_nand(mtd);
>> >> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH *
>> >> chip->ecc.strength,
>> >> +					  BITS_PER_BYTE);
>> >> +
>> >> +	if (section > 0)
>> >> +		return -ERANGE;
>> >> +
>> >> +	oobregion->offset = SKIP_SPARE_BYTES +
>> >> +			    round_up(bytes_per_step * chip->ecc.steps, 4);
>> >> +	oobregion->length = mtd->oobsize - oobregion->offset;
>> >> +
>> >> +	return 0;
>> >> +}
>> >> +
>> >> +/*
>> >> + * Layout with tag bytes is
>> >> + *
>> >> + *
>> >> ------------------------------------------------------------------------
>> >> -- + * | main area                       | skip bytes | tag bytes |
>> >> parity | .. | + *
>> >> ------------------------------------------------------------------------
>> >> -- + *
>> >> + * If not tag bytes are written, parity moves right after skip bytes!
>> >> + */
>> >> +static const struct mtd_ooblayout_ops tegra_nand_oob_bch_ops = {
>> >> +	.ecc = tegra_nand_ooblayout_bch_ecc,
>> >> +	.free = tegra_nand_ooblayout_bch_free,
>> >> +};
>> >> +
>> >> +static irqreturn_t tegra_nand_irq(int irq, void *data)
>> >> +{
>> >> +	struct tegra_nand_controller *ctrl = data;
>> >> +	u32 isr, dma;
>> >> +
>> >> +	isr = readl_relaxed(ctrl->regs + ISR);
>> >> +	dma = readl_relaxed(ctrl->regs + DMA_CTRL);
>> >> +	dev_dbg(ctrl->dev, "isr %08x\n", isr);
>> >> +
>> >> +	if (!isr && !(dma & DMA_CTRL_IS_DONE))
>> >> +		return IRQ_NONE;
>> >> +
>> >> +	/*
>> >> +	 * The bit name is somewhat missleading: This is also set when
>> >> +	 * HW ECC was successful. The data sheet states:
>> >> +	 * Correctable OR Un-correctable errors occurred in the DMA
> transfer...
>> >> +	 */
>> >> +	if (isr & ISR_CORRFAIL_ERR)
>> >> +		ctrl->last_read_error = true;
>> >> +
>> >> +	if (isr & ISR_CMD_DONE)
>> >> +		complete(&ctrl->command_complete);
>> >> +
>> >> +	if (isr & ISR_UND)
>> >> +		dev_err(ctrl->dev, "FIFO underrun\n");
>> >> +
>> >> +	if (isr & ISR_OVR)
>> >> +		dev_err(ctrl->dev, "FIFO overrun\n");
>> >> +
>> >> +	/* handle DMA interrupts */
>> >> +	if (dma & DMA_CTRL_IS_DONE) {
>> >> +		writel_relaxed(dma, ctrl->regs + DMA_CTRL);
>> >> +		complete(&ctrl->dma_complete);
>> >> +	}
>> >> +
>> >> +	/* clear interrupts */
>> >> +	writel_relaxed(isr, ctrl->regs + ISR);
>> >> +
>> >> +	return IRQ_HANDLED;
>> >> +}
>> >> +
>> >> +static const char * const tegra_nand_reg_names[] = {
>> >> +	"COMMAND",
>> >> +	"STATUS",
>> >> +	"ISR",
>> >> +	"IER",
>> >> +	"CONFIG",
>> >> +	"TIMING",
>> >> +	NULL,
>> >> +	"TIMING2",
>> >> +	"CMD_REG1",
>> >> +	"CMD_REG2",
>> >> +	"ADDR_REG1",
>> >> +	"ADDR_REG2",
>> >> +	"DMA_MST_CTRL",
>> >> +	"DMA_CFG_A",
>> >> +	"DMA_CFG_B",
>> >> +	"FIFO_CTRL",
>> >> +};
>> >> +
>> >> +static void tegra_nand_dump_reg(struct tegra_nand_controller *ctrl)
>> >> +{
>> >> +	u32 reg;
>> >> +	int i;
>> >> +
>> >> +	dev_err(ctrl->dev, "Tegra NAND controller register dump\n");
>> >> +	for (i = 0; i < ARRAY_SIZE(tegra_nand_reg_names); i++) {
>> >> +		const char *reg_name = tegra_nand_reg_names[i];
>> >> +
>> >> +		if (!reg_name)
>> >> +			continue;
>> >> +
>> >> +		reg = readl_relaxed(ctrl->regs + (i * 4));
>> >> +		dev_err(ctrl->dev, "%s: 0x%08x\n", reg_name, reg);
>> >> +	}
>> >> +}
>> >> +
>> >> +static int tegra_nand_cmd(struct nand_chip *chip,
>> >> +			 const struct nand_subop *subop)
>> >> +{
>> >> +	const struct nand_op_instr *instr;
>> >> +	const struct nand_op_instr *instr_data_in = NULL;
>> >> +	struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
>> >> +	unsigned int op_id, size = 0, offset = 0;
>> >> +	bool first_cmd = true;
>> >> +	u32 reg, cmd = 0;
>> >> +	int ret;
>> >> +
>> >> +	for (op_id = 0; op_id < subop->ninstrs; op_id++) {
>> >> +		unsigned int naddrs, i;
>> >> +		const u8 *addrs;
>> >> +		u32 addr1 = 0, addr2 = 0;
>> >> +
>> >> +		instr = &subop->instrs[op_id];
>> >> +
>> >> +		switch (instr->type) {
>> >> +		case NAND_OP_CMD_INSTR:
>> >> +			if (first_cmd) {
>> >> +				cmd |= CMD_CLE;
>> >> +				writel_relaxed(instr->ctx.cmd.opcode,
>> >> +					       ctrl->regs + CMD_1);
>> >> +			} else {
>> >> +				cmd |= CMD_SEC_CMD;
>> >> +				writel_relaxed(instr->ctx.cmd.opcode,
>> >> +					       ctrl->regs + CMD_2);
>> >> +			}
>> >> +			first_cmd = false;
>> >> +			break;
>> >> +		case NAND_OP_ADDR_INSTR:
>> >> +			offset = nand_subop_get_addr_start_off(subop, op_id);
>> >> +			naddrs = nand_subop_get_num_addr_cyc(subop, op_id);
>> >> +			addrs = &instr->ctx.addr.addrs[offset];
>> >> +
>> >> +			cmd |= CMD_ALE | CMD_ALE_SIZE(naddrs);
>> >> +			for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
>> >> +				addr1 |= *addrs++ << (BITS_PER_BYTE * i);
>> >> +			naddrs -= i;
>> >> +			for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
>> >> +				addr2 |= *addrs++ << (BITS_PER_BYTE * i);
>> >> +			writel_relaxed(addr1, ctrl->regs + ADDR_1);
>> >> +			writel_relaxed(addr2, ctrl->regs + ADDR_2);
>> >> +			break;
>> >> +
>> >> +		case NAND_OP_DATA_IN_INSTR:
>> >> +			size = nand_subop_get_data_len(subop, op_id);
>> >> +			offset = nand_subop_get_data_start_off(subop, op_id);
>> >> +
>> >> +			cmd |= CMD_TRANS_SIZE(size) | CMD_PIO | CMD_RX |
>> >> +				CMD_A_VALID;
>> >> +
>> >> +			instr_data_in = instr;
>> >> +			break;
>> >> +
>> >> +		case NAND_OP_DATA_OUT_INSTR:
>> >> +			size = nand_subop_get_data_len(subop, op_id);
>> >> +			offset = nand_subop_get_data_start_off(subop, op_id);
>> >> +
>> >> +			cmd |= CMD_TRANS_SIZE(size) | CMD_PIO | CMD_TX |
>> >> +				CMD_A_VALID;
>> >> +
>> >> +			memcpy(&reg, instr->ctx.data.buf.out + offset, size);
>> >> +			writel_relaxed(reg, ctrl->regs + RESP);
>> >> +
>> >> +			break;
>> >> +		case NAND_OP_WAITRDY_INSTR:
>> >> +			cmd |= CMD_RBSY_CHK;
>> >> +			break;
>> >> +
>> >> +		}
>> >> +	}
>> >> +
>> >> +	cmd |= CMD_GO | CMD_CE(ctrl->cur_chip);
>> >> +	writel_relaxed(cmd, ctrl->regs + CMD);
>> >> +	ret = wait_for_completion_timeout(&ctrl->command_complete,
>> >> +					  msecs_to_jiffies(500));
>> >> +	if (!ret) {
>> >> +		dev_err(ctrl->dev, "CMD timeout\n");
>> >> +		tegra_nand_dump_reg(ctrl);
>> >> +		return -ETIMEDOUT;
>> >> +	}
>> >
>> > - wait_for_completion_timeout() could fail
>>
>> Not according to:
>> https://elixir.bootlin.com/linux/latest/source/kernel/sched/completion.c#L14
>> 0 https://www.kernel.org/doc/Documentation/scheduler/completion.txt
>>
>> Afaik, only the _interruptible variant can fail.
> 
> Okay.
> 
>> Btw, maybe we should use the _io variant?
> 
> Looks like the _io variant is something specific to block/FS subsys and 
> shouldn't be used by the drivers.
> 
>> > - HW shall be reset
>> > - completion shall be re-inited because IRQ could fire just after the
>> > completion timeout
>> >
>> > I'd write it something like this:
>> >
>> > #define INT_MASK	(IER_UND | IER_OVR | IER_CMD_DONE | IER_GIE)
>> >
>> > #define HWSTATUS_MASK	(HWSTATUS_RDSTATUS_MASK(1) |		 \
>> >
>> > 			 HWSTATUS_RDSTATUS_VALUE(0) |		 \
>> > 			 HWSTATUS_RBSY_MASK(NAND_STATUS_READY) | \
>> > 			 HWSTATUS_RBSY_VALUE(NAND_STATUS_READY))
>> >
>> > #define HW_TIMEOUT	500
>> >
>> > void tegra_nand_controller_reset(struct tegra_nand_controller *ctrl)
>> > {
>> >
>> > 	int err;
>> >
>> > 	disable_irq(ctrl->irq);
>> >
>> > 	err = reset_control_reset(ctrl->rst);
>> > 	if (err) {
>> >
>> > 		dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
>> > 		msleep(HW_TIMEOUT);
>> >
>> > 	}
>> >
>> > 	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
>> > 	writel_relaxed(HWSTATUS_MASK, ctrl->regs + HWSTATUS_MASK);
>> > 	writel_relaxed(INT_MASK, ctrl->regs + ISR);
>>
>> If we do a controller reset, there is much more state than that which
>> needs to be restored. A lot of it is not readily available currently
>> (timing, ECC settings...)
>>
>> That seems a lot of work for a code path I do not intend to ever use :-)
> 
> Are you sure that resetting HW resets the timing and other registers 
> configuration? Reset implementation is HW-specific, like for example in a case 
> of a video decoder the registers state is re-intialized on HW reset, but 
> registers configuration is untouched in a case of resetting GPU. I'd suggest 
> to check whether NAND controller resetting affects the HW configuration.

It seems all registers are set back to their documented reset value:

[boot loader/ROM initialized values]
[    1.270253] tegra-nand 70008000.nand: Tegra NAND controller register
dump
[    1.277051] tegra-nand 70008000.nand: COMMAND: 0x66880104
[    1.282457] tegra-nand 70008000.nand: STATUS: 0x00000101
[    1.287763] tegra-nand 70008000.nand: ISR: 0x01000120
[    1.292818] tegra-nand 70008000.nand: IER: 0x00000000
[    1.297863] tegra-nand 70008000.nand: CONFIG: 0x00840000
[    1.303181] tegra-nand 70008000.nand: TIMING: 0x05040000
[    1.308486] tegra-nand 70008000.nand: TIMING2: 0x00000003
[    1.313897] tegra-nand 70008000.nand: CMD_REG1: 0x00000000
[    1.319377] tegra-nand 70008000.nand: CMD_REG2: 0x00000030
[    1.324868] tegra-nand 70008000.nand: ADDR_REG1: 0x03000000
[    1.330435] tegra-nand 70008000.nand: ADDR_REG2: 0x00000000
[    1.336011] tegra-nand 70008000.nand: DMA_MST_CTRL: 0x04100004
[    1.341838] tegra-nand 70008000.nand: DMA_CFG_A: 0x00000fff
[    1.347415] tegra-nand 70008000.nand: DMA_CFG_B: 0x0000001b
[    1.352991] tegra-nand 70008000.nand: FIFO_CTRL: 0x0000aa00
[reset]
[    1.358559] tegra-nand 70008000.nand: Tegra NAND controller register
dump
[    1.365352] tegra-nand 70008000.nand: COMMAND: 0x00800004
[    1.370744] tegra-nand 70008000.nand: STATUS: 0x00000101
[    1.376060] tegra-nand 70008000.nand: ISR: 0x00000100
[    1.381105] tegra-nand 70008000.nand: IER: 0x00000000
[    1.386161] tegra-nand 70008000.nand: CONFIG: 0x10030000
[    1.391466] tegra-nand 70008000.nand: TIMING: 0x00000000
[    1.396782] tegra-nand 70008000.nand: TIMING2: 0x00000000
[    1.402174] tegra-nand 70008000.nand: CMD_REG1: 0x00000000
[    1.407664] tegra-nand 70008000.nand: CMD_REG2: 0x00000000
[    1.413156] tegra-nand 70008000.nand: ADDR_REG1: 0x00000000
[    1.418722] tegra-nand 70008000.nand: ADDR_REG2: 0x00000000
[    1.424297] tegra-nand 70008000.nand: DMA_MST_CTRL: 0x24000000
[    1.430123] tegra-nand 70008000.nand: DMA_CFG_A: 0x00000000
[    1.435698] tegra-nand 70008000.nand: DMA_CFG_B: 0x00000000
[    1.441264] tegra-nand 70008000.nand: FIFO_CTRL: 0x0000aa00

--
Stefan
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On Sunday, 10 June 2018 14:09:24 MSK Stefan Agner wrote:
> On 09.06.2018 14:21, Dmitry Osipenko wrote:
> > On Saturday, 9 June 2018 00:51:01 MSK Stefan Agner wrote:
> >> On 01.06.2018 11:20, Dmitry Osipenko wrote:
> >> > On 01.06.2018 01:16, Stefan Agner wrote:
> >> >> Add support for the NAND flash controller found on NVIDIA
> >> >> Tegra 2 SoCs. This implementation does not make use of the
> >> >> command queue feature. Regular operations/data transfers are
> >> >> done in PIO mode. Page read/writes with hardware ECC make
> >> >> use of the DMA for data transfer.
> >> >> 
> >> >> Signed-off-by: Lucas Stach <dev@lynxeye.de>
> >> >> Signed-off-by: Stefan Agner <stefan@agner.ch>
> >> >> ---
> >> >> 
> >> >>  MAINTAINERS                       |    7 +
> >> >>  drivers/mtd/nand/raw/Kconfig      |    6 +
> >> >>  drivers/mtd/nand/raw/Makefile     |    1 +
> >> >>  drivers/mtd/nand/raw/tegra_nand.c | 1143
> >> >>  +++++++++++++++++++++++++++++
> >> >>  4 files changed, 1157 insertions(+)
> >> >>  create mode 100644 drivers/mtd/nand/raw/tegra_nand.c
> >> >> 
> >> >> diff --git a/MAINTAINERS b/MAINTAINERS
> >> >> index 58b9861ccf99..c2e5571c85d4 100644
> >> >> --- a/MAINTAINERS
> >> >> +++ b/MAINTAINERS
> >> >> @@ -13844,6 +13844,13 @@ M:	Laxman Dewangan <ldewangan@nvidia.com>
> >> >> 
> >> >>  S:	Supported
> >> >>  F:	drivers/input/keyboard/tegra-kbc.c
> >> >> 
> >> >> +TEGRA NAND DRIVER
> >> >> +M:	Stefan Agner <stefan@agner.ch>
> >> >> +M:	Lucas Stach <dev@lynxeye.de>
> >> >> +S:	Maintained
> >> >> +F:	Documentation/devicetree/bindings/mtd/nvidia-tegra20-nand.txt
> >> >> +F:	drivers/mtd/nand/raw/tegra_nand.c
> >> >> +
> >> >> 
> >> >>  TEGRA PWM DRIVER
> >> >>  M:	Thierry Reding <thierry.reding@gmail.com>
> >> >>  S:	Supported
> >> >> 
> >> >> diff --git a/drivers/mtd/nand/raw/Kconfig
> >> >> b/drivers/mtd/nand/raw/Kconfig
> >> >> index 19a2b283fbbe..e9093f52371e 100644
> >> >> --- a/drivers/mtd/nand/raw/Kconfig
> >> >> +++ b/drivers/mtd/nand/raw/Kconfig
> >> >> @@ -534,4 +534,10 @@ config MTD_NAND_MTK
> >> >> 
> >> >>  	  Enables support for NAND controller on MTK SoCs.
> >> >>  	  This controller is found on mt27xx, mt81xx, mt65xx SoCs.
> >> >> 
> >> >> +config MTD_NAND_TEGRA
> >> >> +	tristate "Support for NAND controller on NVIDIA Tegra"
> >> >> +	depends on ARCH_TEGRA || COMPILE_TEST
> >> >> +	help
> >> >> +	  Enables support for NAND flash controller on NVIDIA Tegra SoC.
> >> >> +
> >> >> 
> >> >>  endif # MTD_NAND
> >> >> 
> >> >> diff --git a/drivers/mtd/nand/raw/Makefile
> >> >> b/drivers/mtd/nand/raw/Makefile
> >> >> index 165b7ef9e9a1..d5a5f9832b88 100644
> >> >> --- a/drivers/mtd/nand/raw/Makefile
> >> >> +++ b/drivers/mtd/nand/raw/Makefile
> >> >> @@ -56,6 +56,7 @@ obj-$(CONFIG_MTD_NAND_HISI504)	        +=
> >> >> hisi504_nand.o
> >> >> 
> >> >>  obj-$(CONFIG_MTD_NAND_BRCMNAND)		+= brcmnand/
> >> >>  obj-$(CONFIG_MTD_NAND_QCOM)		+= qcom_nandc.o
> >> >>  obj-$(CONFIG_MTD_NAND_MTK)		+= mtk_ecc.o mtk_nand.o
> >> >> 
> >> >> +obj-$(CONFIG_MTD_NAND_TEGRA)		+= tegra_nand.o
> >> >> 
> >> >>  nand-objs := nand_base.o nand_bbt.o nand_timings.o nand_ids.o
> >> >>  nand-objs += nand_amd.o
> >> >> 
> >> >> diff --git a/drivers/mtd/nand/raw/tegra_nand.c
> >> >> b/drivers/mtd/nand/raw/tegra_nand.c new file mode 100644
> >> >> index 000000000000..e9664f2938a3
> >> >> --- /dev/null
> >> >> +++ b/drivers/mtd/nand/raw/tegra_nand.c
> >> >> @@ -0,0 +1,1143 @@
> >> >> +// SPDX-License-Identifier: GPL-2.0
> >> >> +/*
> >> >> + * Copyright (C) 2018 Stefan Agner <stefan@agner.ch>
> >> >> + * Copyright (C) 2014-2015 Lucas Stach <dev@lynxeye.de>
> >> >> + * Copyright (C) 2012 Avionic Design GmbH
> >> >> + */
> >> >> +
> >> >> +#include <linux/clk.h>
> >> >> +#include <linux/completion.h>
> >> >> +#include <linux/delay.h>
> >> >> +#include <linux/dma-mapping.h>
> >> >> +#include <linux/err.h>
> >> >> +#include <linux/gpio/consumer.h>
> >> >> +#include <linux/interrupt.h>
> >> >> +#include <linux/io.h>
> >> >> +#include <linux/module.h>
> >> >> +#include <linux/mtd/partitions.h>
> >> >> +#include <linux/mtd/rawnand.h>
> >> >> +#include <linux/of.h>
> >> >> +#include <linux/platform_device.h>
> >> >> +#include <linux/reset.h>
> >> >> +
> >> >> +#define CMD					0x00
> >> >> +#define   CMD_GO				BIT(31)
> >> >> +#define   CMD_CLE				BIT(30)
> >> >> +#define   CMD_ALE				BIT(29)
> >> >> +#define   CMD_PIO				BIT(28)
> >> >> +#define   CMD_TX				BIT(27)
> >> >> +#define   CMD_RX				BIT(26)
> >> >> +#define   CMD_SEC_CMD				BIT(25)
> >> >> +#define   CMD_AFT_DAT				BIT(24)
> >> >> +#define   CMD_TRANS_SIZE(x)			(((x - 1) & 0xf) << 20)
> >> >> +#define   CMD_A_VALID				BIT(19)
> >> >> +#define   CMD_B_VALID				BIT(18)
> >> >> +#define   CMD_RD_STATUS_CHK			BIT(17)
> >> >> +#define   CMD_RBSY_CHK				BIT(16)
> >> >> +#define   CMD_CE(x)				BIT((8 + ((x) & 0x7)))
> >> >> +#define   CMD_CLE_SIZE(x)			(((x - 1) & 0x3) << 4)
> >> >> +#define   CMD_ALE_SIZE(x)			(((x - 1) & 0xf) << 0)
> >> >> +
> >> >> +#define STATUS					0x04
> >> >> +
> >> >> +#define ISR					0x08
> >> >> +#define   ISR_CORRFAIL_ERR			BIT(24)
> >> >> +#define   ISR_UND				BIT(7)
> >> >> +#define   ISR_OVR				BIT(6)
> >> >> +#define   ISR_CMD_DONE				BIT(5)
> >> >> +#define   ISR_ECC_ERR				BIT(4)
> >> >> +
> >> >> +#define IER					0x0c
> >> >> +#define   IER_ERR_TRIG_VAL(x)			(((x) & 0xf) << 16)
> >> >> +#define   IER_UND				BIT(7)
> >> >> +#define   IER_OVR				BIT(6)
> >> >> +#define   IER_CMD_DONE				BIT(5)
> >> >> +#define   IER_ECC_ERR				BIT(4)
> >> >> +#define   IER_GIE				BIT(0)
> >> >> +
> >> >> +#define CFG					0x10
> >> >> +#define   CFG_HW_ECC				BIT(31)
> >> >> +#define   CFG_ECC_SEL				BIT(30)
> >> >> +#define   CFG_ERR_COR				BIT(29)
> >> >> +#define   CFG_PIPE_EN				BIT(28)
> >> >> +#define   CFG_TVAL_4				(0 << 24)
> >> >> +#define   CFG_TVAL_6				(1 << 24)
> >> >> +#define   CFG_TVAL_8				(2 << 24)
> >> >> +#define   CFG_SKIP_SPARE			BIT(23)
> >> >> +#define   CFG_BUS_WIDTH_16			BIT(21)
> >> >> +#define   CFG_COM_BSY				BIT(20)
> >> >> +#define   CFG_PS_256				(0 << 16)
> >> >> +#define   CFG_PS_512				(1 << 16)
> >> >> +#define   CFG_PS_1024				(2 << 16)
> >> >> +#define   CFG_PS_2048				(3 << 16)
> >> >> +#define   CFG_PS_4096				(4 << 16)
> >> >> +#define   CFG_SKIP_SPARE_SIZE_4			(0 << 14)
> >> >> +#define   CFG_SKIP_SPARE_SIZE_8			(1 << 14)
> >> >> +#define   CFG_SKIP_SPARE_SIZE_12		(2 << 14)
> >> >> +#define   CFG_SKIP_SPARE_SIZE_16		(3 << 14)
> >> >> +#define   CFG_TAG_BYTE_SIZE(x)			((x) & 0xff)
> >> >> +
> >> >> +#define TIMING_1				0x14
> >> >> +#define   TIMING_TRP_RESP(x)			(((x) & 0xf) << 28)
> >> >> +#define   TIMING_TWB(x)				(((x) & 0xf) << 24)
> >> >> +#define   TIMING_TCR_TAR_TRR(x)			(((x) & 0xf) << 20)
> >> >> +#define   TIMING_TWHR(x)			(((x) & 0xf) << 16)
> >> >> +#define   TIMING_TCS(x)				(((x) & 0x3) << 14)
> >> >> +#define   TIMING_TWH(x)				(((x) & 0x3) << 12)
> >> >> +#define   TIMING_TWP(x)				(((x) & 0xf) <<  8)
> >> >> +#define   TIMING_TRH(x)				(((x) & 0x3) <<  4)
> >> >> +#define   TIMING_TRP(x)				(((x) & 0xf) <<  0)
> >> >> +
> >> >> +#define RESP					0x18
> >> >> +
> >> >> +#define TIMING_2				0x1c
> >> >> +#define   TIMING_TADL(x)			((x) & 0xf)
> >> >> +
> >> >> +#define CMD_1					0x20
> >> >> +#define CMD_2					0x24
> >> >> +#define ADDR_1					0x28
> >> >> +#define ADDR_2					0x2c
> >> >> +
> >> >> +#define DMA_CTRL				0x30
> >> >> +#define   DMA_CTRL_GO				BIT(31)
> >> >> +#define   DMA_CTRL_IN				(0 << 30)
> >> >> +#define   DMA_CTRL_OUT				BIT(30)
> >> >> +#define   DMA_CTRL_PERF_EN			BIT(29)
> >> >> +#define   DMA_CTRL_IE_DONE			BIT(28)
> >> >> +#define   DMA_CTRL_REUSE			BIT(27)
> >> >> +#define   DMA_CTRL_BURST_1			(2 << 24)
> >> >> +#define   DMA_CTRL_BURST_4			(3 << 24)
> >> >> +#define   DMA_CTRL_BURST_8			(4 << 24)
> >> >> +#define   DMA_CTRL_BURST_16			(5 << 24)
> >> >> +#define   DMA_CTRL_IS_DONE			BIT(20)
> >> >> +#define   DMA_CTRL_EN_A				BIT(2)
> >> >> +#define   DMA_CTRL_EN_B				BIT(1)
> >> >> +
> >> >> +#define DMA_CFG_A				0x34
> >> >> +#define DMA_CFG_B				0x38
> >> >> +
> >> >> +#define FIFO_CTRL				0x3c
> >> >> +#define   FIFO_CTRL_CLR_ALL			BIT(3)
> >> >> +
> >> >> +#define DATA_PTR				0x40
> >> >> +#define TAG_PTR					0x44
> >> >> +#define ECC_PTR					0x48
> >> >> +
> >> >> +#define DEC_STATUS				0x4c
> >> >> +#define   DEC_STATUS_A_ECC_FAIL			BIT(1)
> >> >> +#define   DEC_STATUS_ERR_COUNT_MASK		0x00ff0000
> >> >> +#define   DEC_STATUS_ERR_COUNT_SHIFT		16
> >> >> +
> >> >> +#define HWSTATUS_CMD				0x50
> >> >> +#define HWSTATUS_MASK				0x54
> >> >> +#define   HWSTATUS_RDSTATUS_MASK(x)		(((x) & 0xff) << 24)
> >> >> +#define   HWSTATUS_RDSTATUS_VALUE(x)		(((x) & 0xff) << 16)
> >> >> +#define   HWSTATUS_RBSY_MASK(x)			(((x) & 0xff) << 8)
> >> >> +#define   HWSTATUS_RBSY_VALUE(x)		(((x) & 0xff) << 0)
> >> >> +
> >> >> +#define BCH_CONFIG				0xcc
> >> >> +#define   BCH_ENABLE				BIT(0)
> >> >> +#define   BCH_TVAL_4				(0 << 4)
> >> >> +#define   BCH_TVAL_8				(1 << 4)
> >> >> +#define   BCH_TVAL_14				(2 << 4)
> >> >> +#define   BCH_TVAL_16				(3 << 4)
> >> >> +
> >> >> +#define DEC_STAT_RESULT				0xd0
> >> >> +#define DEC_STAT_BUF				0xd4
> >> >> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_MASK	0xff000000
> >> >> +#define   DEC_STAT_BUF_FAIL_SEC_FLAG_SHIFT	24
> >> >> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_MASK	0x00ff0000
> >> >> +#define   DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT	16
> >> >> +#define   DEC_STAT_BUF_MAX_CORR_CNT_MASK	0x00001f00
> >> >> +#define   DEC_STAT_BUF_MAX_CORR_CNT_SHIFT	8
> >> >> +
> >> >> +#define OFFSET(val, off)		((val) < (off) ? 0 : (val) - (off))
> >> >> +
> >> >> +#define SKIP_SPARE_BYTES	4
> >> >> +#define BITS_PER_STEP_RS	18
> >> >> +#define BITS_PER_STEP_BCH	13
> >> >> +
> >> >> +struct tegra_nand_controller {
> >> >> +	struct nand_hw_control controller;
> >> >> +	void __iomem *regs;
> >> >> +	struct clk *clk;
> >> >> +	struct device *dev;
> >> >> +	struct completion command_complete;
> >> >> +	struct completion dma_complete;
> >> >> +	bool last_read_error;
> >> >> +	int cur_chip;
> >> >> +	struct nand_chip *chip;
> >> >> +};
> >> >> +
> >> >> +struct tegra_nand_chip {
> >> >> +	struct nand_chip chip;
> >> >> +	struct gpio_desc *wp_gpio;
> >> >> +	struct mtd_oob_region tag;
> >> >> +};
> >> >> +
> >> >> +static inline struct tegra_nand_controller *to_tegra_ctrl(
> >> >> +						struct nand_hw_control *hw_ctrl)
> >> >> +{
> >> >> +	return container_of(hw_ctrl, struct tegra_nand_controller,
> > 
> > controller);
> > 
> >> >> +}
> >> >> +
> >> >> +static inline struct tegra_nand_chip *to_tegra_chip(struct nand_chip
> >> >> *chip) +{
> >> >> +	return container_of(chip, struct tegra_nand_chip, chip);
> >> >> +}
> >> >> +
> >> >> +static int tegra_nand_ooblayout_rs_ecc(struct mtd_info *mtd, int
> >> >> section,
> >> >> +				       struct mtd_oob_region *oobregion)
> >> >> +{
> >> >> +	struct nand_chip *chip = mtd_to_nand(mtd);
> >> >> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS *
> >> >> chip->ecc.strength,
> >> >> +					  BITS_PER_BYTE);
> >> >> +
> >> >> +	if (section > 0)
> >> >> +		return -ERANGE;
> >> >> +
> >> >> +	oobregion->offset = SKIP_SPARE_BYTES;
> >> >> +	oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 
4);
> >> >> +
> >> >> +	return 0;
> >> >> +}
> >> >> +
> >> >> +static int tegra_nand_ooblayout_rs_free(struct mtd_info *mtd, int
> >> >> section,
> >> >> +					struct mtd_oob_region *oobregion)
> >> >> +{
> >> >> +	struct nand_chip *chip = mtd_to_nand(mtd);
> >> >> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS *
> >> >> chip->ecc.strength,
> >> >> +					  BITS_PER_BYTE);
> >> >> +
> >> >> +	if (section > 0)
> >> >> +		return -ERANGE;
> >> >> +
> >> >> +	oobregion->offset = SKIP_SPARE_BYTES +
> >> >> +			    round_up(bytes_per_step * chip->ecc.steps, 4);
> >> >> +	oobregion->length = mtd->oobsize - oobregion->offset;
> >> >> +
> >> >> +	return 0;
> >> >> +}
> >> >> +
> >> >> +static const struct mtd_ooblayout_ops tegra_nand_oob_rs_ops = {
> >> >> +	.ecc = tegra_nand_ooblayout_rs_ecc,
> >> >> +	.free = tegra_nand_ooblayout_rs_free,
> >> >> +};
> >> >> +
> >> >> +static int tegra_nand_ooblayout_bch_ecc(struct mtd_info *mtd, int
> >> >> section,
> >> >> +				       struct mtd_oob_region *oobregion)
> >> >> +{
> >> >> +	struct nand_chip *chip = mtd_to_nand(mtd);
> >> >> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH *
> >> >> chip->ecc.strength,
> >> >> +					  BITS_PER_BYTE);
> >> >> +
> >> >> +	if (section > 0)
> >> >> +		return -ERANGE;
> >> >> +
> >> >> +	oobregion->offset = SKIP_SPARE_BYTES;
> >> >> +	oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 
4);
> >> >> +
> >> >> +	return 0;
> >> >> +}
> >> >> +
> >> >> +static int tegra_nand_ooblayout_bch_free(struct mtd_info *mtd, int
> >> >> section, +					struct mtd_oob_region *oobregion)
> >> >> +{
> >> >> +	struct nand_chip *chip = mtd_to_nand(mtd);
> >> >> +	int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH *
> >> >> chip->ecc.strength,
> >> >> +					  BITS_PER_BYTE);
> >> >> +
> >> >> +	if (section > 0)
> >> >> +		return -ERANGE;
> >> >> +
> >> >> +	oobregion->offset = SKIP_SPARE_BYTES +
> >> >> +			    round_up(bytes_per_step * chip->ecc.steps, 4);
> >> >> +	oobregion->length = mtd->oobsize - oobregion->offset;
> >> >> +
> >> >> +	return 0;
> >> >> +}
> >> >> +
> >> >> +/*
> >> >> + * Layout with tag bytes is
> >> >> + *
> >> >> + *
> >> >> ----------------------------------------------------------------------
> >> >> --
> >> >> -- + * | main area                       | skip bytes | tag bytes |
> >> >> parity | .. | + *
> >> >> ----------------------------------------------------------------------
> >> >> --
> >> >> -- + *
> >> >> + * If not tag bytes are written, parity moves right after skip bytes!
> >> >> + */
> >> >> +static const struct mtd_ooblayout_ops tegra_nand_oob_bch_ops = {
> >> >> +	.ecc = tegra_nand_ooblayout_bch_ecc,
> >> >> +	.free = tegra_nand_ooblayout_bch_free,
> >> >> +};
> >> >> +
> >> >> +static irqreturn_t tegra_nand_irq(int irq, void *data)
> >> >> +{
> >> >> +	struct tegra_nand_controller *ctrl = data;
> >> >> +	u32 isr, dma;
> >> >> +
> >> >> +	isr = readl_relaxed(ctrl->regs + ISR);
> >> >> +	dma = readl_relaxed(ctrl->regs + DMA_CTRL);
> >> >> +	dev_dbg(ctrl->dev, "isr %08x\n", isr);
> >> >> +
> >> >> +	if (!isr && !(dma & DMA_CTRL_IS_DONE))
> >> >> +		return IRQ_NONE;
> >> >> +
> >> >> +	/*
> >> >> +	 * The bit name is somewhat missleading: This is also set when
> >> >> +	 * HW ECC was successful. The data sheet states:
> >> >> +	 * Correctable OR Un-correctable errors occurred in the DMA
> > 
> > transfer...
> > 
> >> >> +	 */
> >> >> +	if (isr & ISR_CORRFAIL_ERR)
> >> >> +		ctrl->last_read_error = true;
> >> >> +
> >> >> +	if (isr & ISR_CMD_DONE)
> >> >> +		complete(&ctrl->command_complete);
> >> >> +
> >> >> +	if (isr & ISR_UND)
> >> >> +		dev_err(ctrl->dev, "FIFO underrun\n");
> >> >> +
> >> >> +	if (isr & ISR_OVR)
> >> >> +		dev_err(ctrl->dev, "FIFO overrun\n");
> >> >> +
> >> >> +	/* handle DMA interrupts */
> >> >> +	if (dma & DMA_CTRL_IS_DONE) {
> >> >> +		writel_relaxed(dma, ctrl->regs + DMA_CTRL);
> >> >> +		complete(&ctrl->dma_complete);
> >> >> +	}
> >> >> +
> >> >> +	/* clear interrupts */
> >> >> +	writel_relaxed(isr, ctrl->regs + ISR);
> >> >> +
> >> >> +	return IRQ_HANDLED;
> >> >> +}
> >> >> +
> >> >> +static const char * const tegra_nand_reg_names[] = {
> >> >> +	"COMMAND",
> >> >> +	"STATUS",
> >> >> +	"ISR",
> >> >> +	"IER",
> >> >> +	"CONFIG",
> >> >> +	"TIMING",
> >> >> +	NULL,
> >> >> +	"TIMING2",
> >> >> +	"CMD_REG1",
> >> >> +	"CMD_REG2",
> >> >> +	"ADDR_REG1",
> >> >> +	"ADDR_REG2",
> >> >> +	"DMA_MST_CTRL",
> >> >> +	"DMA_CFG_A",
> >> >> +	"DMA_CFG_B",
> >> >> +	"FIFO_CTRL",
> >> >> +};
> >> >> +
> >> >> +static void tegra_nand_dump_reg(struct tegra_nand_controller *ctrl)
> >> >> +{
> >> >> +	u32 reg;
> >> >> +	int i;
> >> >> +
> >> >> +	dev_err(ctrl->dev, "Tegra NAND controller register dump\n");
> >> >> +	for (i = 0; i < ARRAY_SIZE(tegra_nand_reg_names); i++) {
> >> >> +		const char *reg_name = tegra_nand_reg_names[i];
> >> >> +
> >> >> +		if (!reg_name)
> >> >> +			continue;
> >> >> +
> >> >> +		reg = readl_relaxed(ctrl->regs + (i * 4));
> >> >> +		dev_err(ctrl->dev, "%s: 0x%08x\n", reg_name, reg);
> >> >> +	}
> >> >> +}
> >> >> +
> >> >> +static int tegra_nand_cmd(struct nand_chip *chip,
> >> >> +			 const struct nand_subop *subop)
> >> >> +{
> >> >> +	const struct nand_op_instr *instr;
> >> >> +	const struct nand_op_instr *instr_data_in = NULL;
> >> >> +	struct tegra_nand_controller *ctrl =
> >> >> to_tegra_ctrl(chip->controller);
> >> >> +	unsigned int op_id, size = 0, offset = 0;
> >> >> +	bool first_cmd = true;
> >> >> +	u32 reg, cmd = 0;
> >> >> +	int ret;
> >> >> +
> >> >> +	for (op_id = 0; op_id < subop->ninstrs; op_id++) {
> >> >> +		unsigned int naddrs, i;
> >> >> +		const u8 *addrs;
> >> >> +		u32 addr1 = 0, addr2 = 0;
> >> >> +
> >> >> +		instr = &subop->instrs[op_id];
> >> >> +
> >> >> +		switch (instr->type) {
> >> >> +		case NAND_OP_CMD_INSTR:
> >> >> +			if (first_cmd) {
> >> >> +				cmd |= CMD_CLE;
> >> >> +				writel_relaxed(instr->ctx.cmd.opcode,
> >> >> +					       ctrl->regs + CMD_1);
> >> >> +			} else {
> >> >> +				cmd |= CMD_SEC_CMD;
> >> >> +				writel_relaxed(instr->ctx.cmd.opcode,
> >> >> +					       ctrl->regs + CMD_2);
> >> >> +			}
> >> >> +			first_cmd = false;
> >> >> +			break;
> >> >> +		case NAND_OP_ADDR_INSTR:
> >> >> +			offset = nand_subop_get_addr_start_off(subop, op_id);
> >> >> +			naddrs = nand_subop_get_num_addr_cyc(subop, op_id);
> >> >> +			addrs = &instr->ctx.addr.addrs[offset];
> >> >> +
> >> >> +			cmd |= CMD_ALE | CMD_ALE_SIZE(naddrs);
> >> >> +			for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
> >> >> +				addr1 |= *addrs++ << (BITS_PER_BYTE * i);
> >> >> +			naddrs -= i;
> >> >> +			for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
> >> >> +				addr2 |= *addrs++ << (BITS_PER_BYTE * i);
> >> >> +			writel_relaxed(addr1, ctrl->regs + ADDR_1);
> >> >> +			writel_relaxed(addr2, ctrl->regs + ADDR_2);
> >> >> +			break;
> >> >> +
> >> >> +		case NAND_OP_DATA_IN_INSTR:
> >> >> +			size = nand_subop_get_data_len(subop, op_id);
> >> >> +			offset = nand_subop_get_data_start_off(subop, op_id);
> >> >> +
> >> >> +			cmd |= CMD_TRANS_SIZE(size) | CMD_PIO | CMD_RX |
> >> >> +				CMD_A_VALID;
> >> >> +
> >> >> +			instr_data_in = instr;
> >> >> +			break;
> >> >> +
> >> >> +		case NAND_OP_DATA_OUT_INSTR:
> >> >> +			size = nand_subop_get_data_len(subop, op_id);
> >> >> +			offset = nand_subop_get_data_start_off(subop, op_id);
> >> >> +
> >> >> +			cmd |= CMD_TRANS_SIZE(size) | CMD_PIO | CMD_TX |
> >> >> +				CMD_A_VALID;
> >> >> +
> >> >> +			memcpy(&reg, instr->ctx.data.buf.out + offset, size);
> >> >> +			writel_relaxed(reg, ctrl->regs + RESP);
> >> >> +
> >> >> +			break;
> >> >> +		case NAND_OP_WAITRDY_INSTR:
> >> >> +			cmd |= CMD_RBSY_CHK;
> >> >> +			break;
> >> >> +
> >> >> +		}
> >> >> +	}
> >> >> +
> >> >> +	cmd |= CMD_GO | CMD_CE(ctrl->cur_chip);
> >> >> +	writel_relaxed(cmd, ctrl->regs + CMD);
> >> >> +	ret = wait_for_completion_timeout(&ctrl->command_complete,
> >> >> +					  msecs_to_jiffies(500));
> >> >> +	if (!ret) {
> >> >> +		dev_err(ctrl->dev, "CMD timeout\n");
> >> >> +		tegra_nand_dump_reg(ctrl);
> >> >> +		return -ETIMEDOUT;
> >> >> +	}
> >> > 
> >> > - wait_for_completion_timeout() could fail
> >> 
> >> Not according to:
> >> https://elixir.bootlin.com/linux/latest/source/kernel/sched/completion.c#
> >> L14 0 https://www.kernel.org/doc/Documentation/scheduler/completion.txt
> >> 
> >> Afaik, only the _interruptible variant can fail.
> > 
> > Okay.
> > 
> >> Btw, maybe we should use the _io variant?
> > 
> > Looks like the _io variant is something specific to block/FS subsys and
> > shouldn't be used by the drivers.
> > 
> >> > - HW shall be reset
> >> > - completion shall be re-inited because IRQ could fire just after the
> >> > completion timeout
> >> > 
> >> > I'd write it something like this:
> >> > 
> >> > #define INT_MASK	(IER_UND | IER_OVR | IER_CMD_DONE | IER_GIE)
> >> > 
> >> > #define HWSTATUS_MASK	(HWSTATUS_RDSTATUS_MASK(1) |		 \
> >> > 
> >> > 			 HWSTATUS_RDSTATUS_VALUE(0) |		 \
> >> > 			 HWSTATUS_RBSY_MASK(NAND_STATUS_READY) | \
> >> > 			 HWSTATUS_RBSY_VALUE(NAND_STATUS_READY))
> >> > 
> >> > #define HW_TIMEOUT	500
> >> > 
> >> > void tegra_nand_controller_reset(struct tegra_nand_controller *ctrl)
> >> > {
> >> > 
> >> > 	int err;
> >> > 	
> >> > 	disable_irq(ctrl->irq);
> >> > 	
> >> > 	err = reset_control_reset(ctrl->rst);
> >> > 	if (err) {
> >> > 	
> >> > 		dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
> >> > 		msleep(HW_TIMEOUT);
> >> > 	
> >> > 	}
> >> > 	
> >> > 	writel_relaxed(NAND_CMD_STATUS, ctrl->regs + HWSTATUS_CMD);
> >> > 	writel_relaxed(HWSTATUS_MASK, ctrl->regs + HWSTATUS_MASK);
> >> > 	writel_relaxed(INT_MASK, ctrl->regs + ISR);
> >> 
> >> If we do a controller reset, there is much more state than that which
> >> needs to be restored. A lot of it is not readily available currently
> >> (timing, ECC settings...)
> >> 
> >> That seems a lot of work for a code path I do not intend to ever use :-)
> > 
> > Are you sure that resetting HW resets the timing and other registers
> > configuration? Reset implementation is HW-specific, like for example in a
> > case of a video decoder the registers state is re-intialized on HW reset,
> > but registers configuration is untouched in a case of resetting GPU. I'd
> > suggest to check whether NAND controller resetting affects the HW
> > configuration.
> It seems all registers are set back to their documented reset value:
> 
> [boot loader/ROM initialized values]
> [    1.270253] tegra-nand 70008000.nand: Tegra NAND controller register
> dump
> [    1.277051] tegra-nand 70008000.nand: COMMAND: 0x66880104
> [    1.282457] tegra-nand 70008000.nand: STATUS: 0x00000101
> [    1.287763] tegra-nand 70008000.nand: ISR: 0x01000120
> [    1.292818] tegra-nand 70008000.nand: IER: 0x00000000
> [    1.297863] tegra-nand 70008000.nand: CONFIG: 0x00840000
> [    1.303181] tegra-nand 70008000.nand: TIMING: 0x05040000
> [    1.308486] tegra-nand 70008000.nand: TIMING2: 0x00000003
> [    1.313897] tegra-nand 70008000.nand: CMD_REG1: 0x00000000
> [    1.319377] tegra-nand 70008000.nand: CMD_REG2: 0x00000030
> [    1.324868] tegra-nand 70008000.nand: ADDR_REG1: 0x03000000
> [    1.330435] tegra-nand 70008000.nand: ADDR_REG2: 0x00000000
> [    1.336011] tegra-nand 70008000.nand: DMA_MST_CTRL: 0x04100004
> [    1.341838] tegra-nand 70008000.nand: DMA_CFG_A: 0x00000fff
> [    1.347415] tegra-nand 70008000.nand: DMA_CFG_B: 0x0000001b
> [    1.352991] tegra-nand 70008000.nand: FIFO_CTRL: 0x0000aa00
> [reset]
> [    1.358559] tegra-nand 70008000.nand: Tegra NAND controller register
> dump
> [    1.365352] tegra-nand 70008000.nand: COMMAND: 0x00800004
> [    1.370744] tegra-nand 70008000.nand: STATUS: 0x00000101
> [    1.376060] tegra-nand 70008000.nand: ISR: 0x00000100
> [    1.381105] tegra-nand 70008000.nand: IER: 0x00000000
> [    1.386161] tegra-nand 70008000.nand: CONFIG: 0x10030000
> [    1.391466] tegra-nand 70008000.nand: TIMING: 0x00000000
> [    1.396782] tegra-nand 70008000.nand: TIMING2: 0x00000000
> [    1.402174] tegra-nand 70008000.nand: CMD_REG1: 0x00000000
> [    1.407664] tegra-nand 70008000.nand: CMD_REG2: 0x00000000
> [    1.413156] tegra-nand 70008000.nand: ADDR_REG1: 0x00000000
> [    1.418722] tegra-nand 70008000.nand: ADDR_REG2: 0x00000000
> [    1.424297] tegra-nand 70008000.nand: DMA_MST_CTRL: 0x24000000
> [    1.430123] tegra-nand 70008000.nand: DMA_CFG_A: 0x00000000
> [    1.435698] tegra-nand 70008000.nand: DMA_CFG_B: 0x00000000
> [    1.441264] tegra-nand 70008000.nand: FIFO_CTRL: 0x0000aa00

Alright, then indeed it's not really worth to bother with HW resetting here.  
Probably only a kernel module reload or a reboot will help if HW is hung. 
Maybe NAND controller / chip recovering is something that NAND core should be 
handling in a such case by providing a nand_controller_reset() hook?


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On Sun, 10 Jun 2018 18:00:06 +0300
Dmitry Osipenko <digetx@gmail.com> wrote:

> > >> That seems a lot of work for a code path I do not intend to ever use :-)  
> > > 
> > > Are you sure that resetting HW resets the timing and other registers
> > > configuration? Reset implementation is HW-specific, like for example in a
> > > case of a video decoder the registers state is re-intialized on HW reset,
> > > but registers configuration is untouched in a case of resetting GPU. I'd
> > > suggest to check whether NAND controller resetting affects the HW
> > > configuration.  
> > It seems all registers are set back to their documented reset value:
> > 
> > [boot loader/ROM initialized values]
> > [    1.270253] tegra-nand 70008000.nand: Tegra NAND controller register
> > dump
> > [    1.277051] tegra-nand 70008000.nand: COMMAND: 0x66880104
> > [    1.282457] tegra-nand 70008000.nand: STATUS: 0x00000101
> > [    1.287763] tegra-nand 70008000.nand: ISR: 0x01000120
> > [    1.292818] tegra-nand 70008000.nand: IER: 0x00000000
> > [    1.297863] tegra-nand 70008000.nand: CONFIG: 0x00840000
> > [    1.303181] tegra-nand 70008000.nand: TIMING: 0x05040000
> > [    1.308486] tegra-nand 70008000.nand: TIMING2: 0x00000003
> > [    1.313897] tegra-nand 70008000.nand: CMD_REG1: 0x00000000
> > [    1.319377] tegra-nand 70008000.nand: CMD_REG2: 0x00000030
> > [    1.324868] tegra-nand 70008000.nand: ADDR_REG1: 0x03000000
> > [    1.330435] tegra-nand 70008000.nand: ADDR_REG2: 0x00000000
> > [    1.336011] tegra-nand 70008000.nand: DMA_MST_CTRL: 0x04100004
> > [    1.341838] tegra-nand 70008000.nand: DMA_CFG_A: 0x00000fff
> > [    1.347415] tegra-nand 70008000.nand: DMA_CFG_B: 0x0000001b
> > [    1.352991] tegra-nand 70008000.nand: FIFO_CTRL: 0x0000aa00
> > [reset]
> > [    1.358559] tegra-nand 70008000.nand: Tegra NAND controller register
> > dump
> > [    1.365352] tegra-nand 70008000.nand: COMMAND: 0x00800004
> > [    1.370744] tegra-nand 70008000.nand: STATUS: 0x00000101
> > [    1.376060] tegra-nand 70008000.nand: ISR: 0x00000100
> > [    1.381105] tegra-nand 70008000.nand: IER: 0x00000000
> > [    1.386161] tegra-nand 70008000.nand: CONFIG: 0x10030000
> > [    1.391466] tegra-nand 70008000.nand: TIMING: 0x00000000
> > [    1.396782] tegra-nand 70008000.nand: TIMING2: 0x00000000
> > [    1.402174] tegra-nand 70008000.nand: CMD_REG1: 0x00000000
> > [    1.407664] tegra-nand 70008000.nand: CMD_REG2: 0x00000000
> > [    1.413156] tegra-nand 70008000.nand: ADDR_REG1: 0x00000000
> > [    1.418722] tegra-nand 70008000.nand: ADDR_REG2: 0x00000000
> > [    1.424297] tegra-nand 70008000.nand: DMA_MST_CTRL: 0x24000000
> > [    1.430123] tegra-nand 70008000.nand: DMA_CFG_A: 0x00000000
> > [    1.435698] tegra-nand 70008000.nand: DMA_CFG_B: 0x00000000
> > [    1.441264] tegra-nand 70008000.nand: FIFO_CTRL: 0x0000aa00  
> 
> Alright, then indeed it's not really worth to bother with HW resetting here.  
> Probably only a kernel module reload or a reboot will help if HW is hung. 
> Maybe NAND controller / chip recovering is something that NAND core should be 
> handling in a such case by providing a nand_controller_reset() hook?
> 

I don't see what the core could do to help with that. We'd end up with
a new hook implemented by the controller that would be called by the
controller driver when it knows it's safe to reset the controller. So,
why bother exposing that in the core?

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On Sunday, 10 June 2018 18:32:02 MSK Boris Brezillon wrote:
> On Sun, 10 Jun 2018 18:00:06 +0300
> 
> Dmitry Osipenko <digetx@gmail.com> wrote:
> > > >> That seems a lot of work for a code path I do not intend to ever use
> > > >> :-)
> > > > 
> > > > Are you sure that resetting HW resets the timing and other registers
> > > > configuration? Reset implementation is HW-specific, like for example
> > > > in a
> > > > case of a video decoder the registers state is re-intialized on HW
> > > > reset,
> > > > but registers configuration is untouched in a case of resetting GPU.
> > > > I'd
> > > > suggest to check whether NAND controller resetting affects the HW
> > > > configuration.
> > > 
> > > It seems all registers are set back to their documented reset value:
> > > 
> > > [boot loader/ROM initialized values]
> > > [    1.270253] tegra-nand 70008000.nand: Tegra NAND controller register
> > > dump
> > > [    1.277051] tegra-nand 70008000.nand: COMMAND: 0x66880104
> > > [    1.282457] tegra-nand 70008000.nand: STATUS: 0x00000101
> > > [    1.287763] tegra-nand 70008000.nand: ISR: 0x01000120
> > > [    1.292818] tegra-nand 70008000.nand: IER: 0x00000000
> > > [    1.297863] tegra-nand 70008000.nand: CONFIG: 0x00840000
> > > [    1.303181] tegra-nand 70008000.nand: TIMING: 0x05040000
> > > [    1.308486] tegra-nand 70008000.nand: TIMING2: 0x00000003
> > > [    1.313897] tegra-nand 70008000.nand: CMD_REG1: 0x00000000
> > > [    1.319377] tegra-nand 70008000.nand: CMD_REG2: 0x00000030
> > > [    1.324868] tegra-nand 70008000.nand: ADDR_REG1: 0x03000000
> > > [    1.330435] tegra-nand 70008000.nand: ADDR_REG2: 0x00000000
> > > [    1.336011] tegra-nand 70008000.nand: DMA_MST_CTRL: 0x04100004
> > > [    1.341838] tegra-nand 70008000.nand: DMA_CFG_A: 0x00000fff
> > > [    1.347415] tegra-nand 70008000.nand: DMA_CFG_B: 0x0000001b
> > > [    1.352991] tegra-nand 70008000.nand: FIFO_CTRL: 0x0000aa00
> > > [reset]
> > > [    1.358559] tegra-nand 70008000.nand: Tegra NAND controller register
> > > dump
> > > [    1.365352] tegra-nand 70008000.nand: COMMAND: 0x00800004
> > > [    1.370744] tegra-nand 70008000.nand: STATUS: 0x00000101
> > > [    1.376060] tegra-nand 70008000.nand: ISR: 0x00000100
> > > [    1.381105] tegra-nand 70008000.nand: IER: 0x00000000
> > > [    1.386161] tegra-nand 70008000.nand: CONFIG: 0x10030000
> > > [    1.391466] tegra-nand 70008000.nand: TIMING: 0x00000000
> > > [    1.396782] tegra-nand 70008000.nand: TIMING2: 0x00000000
> > > [    1.402174] tegra-nand 70008000.nand: CMD_REG1: 0x00000000
> > > [    1.407664] tegra-nand 70008000.nand: CMD_REG2: 0x00000000
> > > [    1.413156] tegra-nand 70008000.nand: ADDR_REG1: 0x00000000
> > > [    1.418722] tegra-nand 70008000.nand: ADDR_REG2: 0x00000000
> > > [    1.424297] tegra-nand 70008000.nand: DMA_MST_CTRL: 0x24000000
> > > [    1.430123] tegra-nand 70008000.nand: DMA_CFG_A: 0x00000000
> > > [    1.435698] tegra-nand 70008000.nand: DMA_CFG_B: 0x00000000
> > > [    1.441264] tegra-nand 70008000.nand: FIFO_CTRL: 0x0000aa00
> > 
> > Alright, then indeed it's not really worth to bother with HW resetting
> > here. Probably only a kernel module reload or a reboot will help if HW is
> > hung. Maybe NAND controller / chip recovering is something that NAND core
> > should be handling in a such case by providing a nand_controller_reset()
> > hook?
> I don't see what the core could do to help with that. We'd end up with
> a new hook implemented by the controller that would be called by the
> controller driver when it knows it's safe to reset the controller. So,
> why bother exposing that in the core?

Giving a driver more flexibility is always a good thing. I'm not really 
familiar with mtd/ and maybe indeed it doesn't make much sense to move HW 
resetting to NAND core, though it looked to me that it should be always safe 
for NAND core to initiate HW resetting after IO failure and hence would be 
cleaner and nicer to have a unified HW reset management rather than to have 
each driver to do its own thing.


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On Mon, 11 Jun 2018 14:45:45 +0300
Dmitry Osipenko <digetx@gmail.com> wrote:

> On Sunday, 10 June 2018 18:32:02 MSK Boris Brezillon wrote:
> > On Sun, 10 Jun 2018 18:00:06 +0300
> > 
> > Dmitry Osipenko <digetx@gmail.com> wrote:  
> > > > >> That seems a lot of work for a code path I do not intend to ever use
> > > > >> :-)  
> > > > > 
> > > > > Are you sure that resetting HW resets the timing and other registers
> > > > > configuration? Reset implementation is HW-specific, like for example
> > > > > in a
> > > > > case of a video decoder the registers state is re-intialized on HW
> > > > > reset,
> > > > > but registers configuration is untouched in a case of resetting GPU.
> > > > > I'd
> > > > > suggest to check whether NAND controller resetting affects the HW
> > > > > configuration.  
> > > > 
> > > > It seems all registers are set back to their documented reset value:
> > > > 
> > > > [boot loader/ROM initialized values]
> > > > [    1.270253] tegra-nand 70008000.nand: Tegra NAND controller register
> > > > dump
> > > > [    1.277051] tegra-nand 70008000.nand: COMMAND: 0x66880104
> > > > [    1.282457] tegra-nand 70008000.nand: STATUS: 0x00000101
> > > > [    1.287763] tegra-nand 70008000.nand: ISR: 0x01000120
> > > > [    1.292818] tegra-nand 70008000.nand: IER: 0x00000000
> > > > [    1.297863] tegra-nand 70008000.nand: CONFIG: 0x00840000
> > > > [    1.303181] tegra-nand 70008000.nand: TIMING: 0x05040000
> > > > [    1.308486] tegra-nand 70008000.nand: TIMING2: 0x00000003
> > > > [    1.313897] tegra-nand 70008000.nand: CMD_REG1: 0x00000000
> > > > [    1.319377] tegra-nand 70008000.nand: CMD_REG2: 0x00000030
> > > > [    1.324868] tegra-nand 70008000.nand: ADDR_REG1: 0x03000000
> > > > [    1.330435] tegra-nand 70008000.nand: ADDR_REG2: 0x00000000
> > > > [    1.336011] tegra-nand 70008000.nand: DMA_MST_CTRL: 0x04100004
> > > > [    1.341838] tegra-nand 70008000.nand: DMA_CFG_A: 0x00000fff
> > > > [    1.347415] tegra-nand 70008000.nand: DMA_CFG_B: 0x0000001b
> > > > [    1.352991] tegra-nand 70008000.nand: FIFO_CTRL: 0x0000aa00
> > > > [reset]
> > > > [    1.358559] tegra-nand 70008000.nand: Tegra NAND controller register
> > > > dump
> > > > [    1.365352] tegra-nand 70008000.nand: COMMAND: 0x00800004
> > > > [    1.370744] tegra-nand 70008000.nand: STATUS: 0x00000101
> > > > [    1.376060] tegra-nand 70008000.nand: ISR: 0x00000100
> > > > [    1.381105] tegra-nand 70008000.nand: IER: 0x00000000
> > > > [    1.386161] tegra-nand 70008000.nand: CONFIG: 0x10030000
> > > > [    1.391466] tegra-nand 70008000.nand: TIMING: 0x00000000
> > > > [    1.396782] tegra-nand 70008000.nand: TIMING2: 0x00000000
> > > > [    1.402174] tegra-nand 70008000.nand: CMD_REG1: 0x00000000
> > > > [    1.407664] tegra-nand 70008000.nand: CMD_REG2: 0x00000000
> > > > [    1.413156] tegra-nand 70008000.nand: ADDR_REG1: 0x00000000
> > > > [    1.418722] tegra-nand 70008000.nand: ADDR_REG2: 0x00000000
> > > > [    1.424297] tegra-nand 70008000.nand: DMA_MST_CTRL: 0x24000000
> > > > [    1.430123] tegra-nand 70008000.nand: DMA_CFG_A: 0x00000000
> > > > [    1.435698] tegra-nand 70008000.nand: DMA_CFG_B: 0x00000000
> > > > [    1.441264] tegra-nand 70008000.nand: FIFO_CTRL: 0x0000aa00  
> > > 
> > > Alright, then indeed it's not really worth to bother with HW resetting
> > > here. Probably only a kernel module reload or a reboot will help if HW is
> > > hung. Maybe NAND controller / chip recovering is something that NAND core
> > > should be handling in a such case by providing a nand_controller_reset()
> > > hook?  
> > I don't see what the core could do to help with that. We'd end up with
> > a new hook implemented by the controller that would be called by the
> > controller driver when it knows it's safe to reset the controller. So,
> > why bother exposing that in the core?  
> 
> Giving a driver more flexibility is always a good thing. I'm not really 
> familiar with mtd/ and maybe indeed it doesn't make much sense to move HW 
> resetting to NAND core, though it looked to me that it should be always safe 
> for NAND core to initiate HW resetting after IO failure and hence would be 
> cleaner and nicer to have a unified HW reset management rather than to have 
> each driver to do its own thing.

No really, the NAND core can't know when it's appropriate to reset the
controller, and what this reset will do, hence it doesn't know if the
chips connected to the controller should also be reset.
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On Monday, 11 June 2018 14:50:13 MSK Boris Brezillon wrote:
> On Mon, 11 Jun 2018 14:45:45 +0300
> 
> Dmitry Osipenko <digetx@gmail.com> wrote:
> > On Sunday, 10 June 2018 18:32:02 MSK Boris Brezillon wrote:
> > > On Sun, 10 Jun 2018 18:00:06 +0300
> > > 
> > > Dmitry Osipenko <digetx@gmail.com> wrote:
> > > > > >> That seems a lot of work for a code path I do not intend to ever
> > > > > >> use
> > > > > >> 
> > > > > >> :-)
> > > > > > 
> > > > > > Are you sure that resetting HW resets the timing and other
> > > > > > registers
> > > > > > configuration? Reset implementation is HW-specific, like for
> > > > > > example
> > > > > > in a
> > > > > > case of a video decoder the registers state is re-intialized on HW
> > > > > > reset,
> > > > > > but registers configuration is untouched in a case of resetting
> > > > > > GPU.
> > > > > > I'd
> > > > > > suggest to check whether NAND controller resetting affects the HW
> > > > > > configuration.
> > > > > 
> > > > > It seems all registers are set back to their documented reset value:
> > > > > 
> > > > > [boot loader/ROM initialized values]
> > > > > [    1.270253] tegra-nand 70008000.nand: Tegra NAND controller
> > > > > register
> > > > > dump
> > > > > [    1.277051] tegra-nand 70008000.nand: COMMAND: 0x66880104
> > > > > [    1.282457] tegra-nand 70008000.nand: STATUS: 0x00000101
> > > > > [    1.287763] tegra-nand 70008000.nand: ISR: 0x01000120
> > > > > [    1.292818] tegra-nand 70008000.nand: IER: 0x00000000
> > > > > [    1.297863] tegra-nand 70008000.nand: CONFIG: 0x00840000
> > > > > [    1.303181] tegra-nand 70008000.nand: TIMING: 0x05040000
> > > > > [    1.308486] tegra-nand 70008000.nand: TIMING2: 0x00000003
> > > > > [    1.313897] tegra-nand 70008000.nand: CMD_REG1: 0x00000000
> > > > > [    1.319377] tegra-nand 70008000.nand: CMD_REG2: 0x00000030
> > > > > [    1.324868] tegra-nand 70008000.nand: ADDR_REG1: 0x03000000
> > > > > [    1.330435] tegra-nand 70008000.nand: ADDR_REG2: 0x00000000
> > > > > [    1.336011] tegra-nand 70008000.nand: DMA_MST_CTRL: 0x04100004
> > > > > [    1.341838] tegra-nand 70008000.nand: DMA_CFG_A: 0x00000fff
> > > > > [    1.347415] tegra-nand 70008000.nand: DMA_CFG_B: 0x0000001b
> > > > > [    1.352991] tegra-nand 70008000.nand: FIFO_CTRL: 0x0000aa00
> > > > > [reset]
> > > > > [    1.358559] tegra-nand 70008000.nand: Tegra NAND controller
> > > > > register
> > > > > dump
> > > > > [    1.365352] tegra-nand 70008000.nand: COMMAND: 0x00800004
> > > > > [    1.370744] tegra-nand 70008000.nand: STATUS: 0x00000101
> > > > > [    1.376060] tegra-nand 70008000.nand: ISR: 0x00000100
> > > > > [    1.381105] tegra-nand 70008000.nand: IER: 0x00000000
> > > > > [    1.386161] tegra-nand 70008000.nand: CONFIG: 0x10030000
> > > > > [    1.391466] tegra-nand 70008000.nand: TIMING: 0x00000000
> > > > > [    1.396782] tegra-nand 70008000.nand: TIMING2: 0x00000000
> > > > > [    1.402174] tegra-nand 70008000.nand: CMD_REG1: 0x00000000
> > > > > [    1.407664] tegra-nand 70008000.nand: CMD_REG2: 0x00000000
> > > > > [    1.413156] tegra-nand 70008000.nand: ADDR_REG1: 0x00000000
> > > > > [    1.418722] tegra-nand 70008000.nand: ADDR_REG2: 0x00000000
> > > > > [    1.424297] tegra-nand 70008000.nand: DMA_MST_CTRL: 0x24000000
> > > > > [    1.430123] tegra-nand 70008000.nand: DMA_CFG_A: 0x00000000
> > > > > [    1.435698] tegra-nand 70008000.nand: DMA_CFG_B: 0x00000000
> > > > > [    1.441264] tegra-nand 70008000.nand: FIFO_CTRL: 0x0000aa00
> > > > 
> > > > Alright, then indeed it's not really worth to bother with HW resetting
> > > > here. Probably only a kernel module reload or a reboot will help if HW
> > > > is
> > > > hung. Maybe NAND controller / chip recovering is something that NAND
> > > > core
> > > > should be handling in a such case by providing a
> > > > nand_controller_reset()
> > > > hook?
> > > 
> > > I don't see what the core could do to help with that. We'd end up with
> > > a new hook implemented by the controller that would be called by the
> > > controller driver when it knows it's safe to reset the controller. So,
> > > why bother exposing that in the core?
> > 
> > Giving a driver more flexibility is always a good thing. I'm not really
> > familiar with mtd/ and maybe indeed it doesn't make much sense to move HW
> > resetting to NAND core, though it looked to me that it should be always
> > safe for NAND core to initiate HW resetting after IO failure and hence
> > would be cleaner and nicer to have a unified HW reset management rather
> > than to have each driver to do its own thing.
> 
> No really, the NAND core can't know when it's appropriate to reset the
> controller, and what this reset will do, hence it doesn't know if the
> chips connected to the controller should also be reset.

Okay!


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