Patchwork [V2,2/2] MTD: MIPS: lantiq: Add NAND support on Lantiq XWAY SoC.

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Submitter John Crispin
Date Aug. 23, 2012, 6:28 p.m.
Message ID <1345746512-22823-1-git-send-email-blogic@openwrt.org>
Download mbox | patch
Permalink /patch/179701/
State New
Headers show

Comments

John Crispin - Aug. 23, 2012, 6:28 p.m.
The driver uses plat_nand. As the platform_device is loaded from DT, we need
to lookup the node and attach our xway specific "struct platform_nand_data"
to it.

Signed-off-by: John Crispin <blogic@openwrt.org>
Cc: linux-mtd@lists.infradead.org
---
Changes in V2
* fix up some sparse warnings

 drivers/mtd/nand/Kconfig     |    8 ++
 drivers/mtd/nand/Makefile    |    1 +
 drivers/mtd/nand/xway_nand.c |  201 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 210 insertions(+), 0 deletions(-)
 create mode 100644 drivers/mtd/nand/xway_nand.c
Artem Bityutskiy - Aug. 24, 2012, 2:32 p.m.
On Thu, 2012-08-23 at 20:28 +0200, John Crispin wrote:
> The driver uses plat_nand. As the platform_device is loaded from DT, we need
> to lookup the node and attach our xway specific "struct platform_nand_data"
> to it.
> 
> Signed-off-by: John Crispin <blogic@openwrt.org>
> Cc: linux-mtd@lists.infradead.org

Pushed to l2-mtd.git, thanks!
David Woodhouse - Sept. 29, 2012, 2:05 p.m.
On Thu, 2012-08-23 at 20:28 +0200, John Crispin wrote:
> 
> +       /* finish with a reset */
> +       spin_lock_irqsave(&ebu_lock, flags);
> +       writeb(NAND_WRITE_CMD_RESET, (void __iomem *) nandaddr);
> +       while ((ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_WR_C) == 0)
> +               ;
> +       spin_unlock_irqrestore(&ebu_lock, flags); 

Disable IRQs, spin forever waiting for hardware.

However much you trust the hardware, you should *never* do this.
Implement a timeout of some kind, please.

You do it again in xway_cmd_ctrl().

I've merged the original patch from l2-mtd.git but please send me a
fix...

Patch

diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 8ca4176..a928fdc 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -607,4 +607,12 @@  config MTD_NAND_FSMC
 	  Enables support for NAND Flash chips on the ST Microelectronics
 	  Flexible Static Memory Controller (FSMC)
 
+config MTD_NAND_XWAY
+	tristate "Support for NAND on Lantiq XWAY SoC"
+	depends on LANTIQ && SOC_TYPE_XWAY
+	select MTD_NAND_PLATFORM
+	help
+	  Enables support for NAND Flash chips on Lantiq XWAY SoCs. NAND is attached
+	  to the External Bus Unit (EBU).
+
 endif # MTD_NAND
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index d4b4d87..52cc861 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -51,5 +51,6 @@  obj-$(CONFIG_MTD_NAND_MPC5121_NFC)	+= mpc5121_nfc.o
 obj-$(CONFIG_MTD_NAND_RICOH)		+= r852.o
 obj-$(CONFIG_MTD_NAND_JZ4740)		+= jz4740_nand.o
 obj-$(CONFIG_MTD_NAND_GPMI_NAND)	+= gpmi-nand/
+obj-$(CONFIG_MTD_NAND_XWAY)		+= xway_nand.o
 
 nand-objs := nand_base.o nand_bbt.o
diff --git a/drivers/mtd/nand/xway_nand.c b/drivers/mtd/nand/xway_nand.c
new file mode 100644
index 0000000..ad94229
--- /dev/null
+++ b/drivers/mtd/nand/xway_nand.c
@@ -0,0 +1,201 @@ 
+/*
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ *
+ *  Copyright (C) 2012 John Crispin <blogic@openwrt.org>
+ */
+
+#include <linux/mtd/nand.h>
+#include <linux/of_gpio.h>
+#include <linux/of_platform.h>
+
+#include <lantiq_soc.h>
+
+/* nand registers */
+#define EBU_ADDSEL1		0x24
+#define EBU_NAND_CON		0xB0
+#define EBU_NAND_WAIT		0xB4
+#define EBU_NAND_ECC0		0xB8
+#define EBU_NAND_ECC_AC		0xBC
+
+/* nand commands */
+#define NAND_CMD_ALE		(1 << 2)
+#define NAND_CMD_CLE		(1 << 3)
+#define NAND_CMD_CS		(1 << 4)
+#define NAND_WRITE_CMD_RESET	0xff
+#define NAND_WRITE_CMD		(NAND_CMD_CS | NAND_CMD_CLE)
+#define NAND_WRITE_ADDR		(NAND_CMD_CS | NAND_CMD_ALE)
+#define NAND_WRITE_DATA		(NAND_CMD_CS)
+#define NAND_READ_DATA		(NAND_CMD_CS)
+#define NAND_WAIT_WR_C		(1 << 3)
+#define NAND_WAIT_RD		(0x1)
+
+/* we need to tel the ebu which addr we mapped the nand to */
+#define ADDSEL1_MASK(x)		(x << 4)
+#define ADDSEL1_REGEN		1
+
+/* we need to tell the EBU that we have nand attached and set it up properly */
+#define BUSCON1_SETUP		(1 << 22)
+#define BUSCON1_BCGEN_RES	(0x3 << 12)
+#define BUSCON1_WAITWRC2	(2 << 8)
+#define BUSCON1_WAITRDC2	(2 << 6)
+#define BUSCON1_HOLDC1		(1 << 4)
+#define BUSCON1_RECOVC1		(1 << 2)
+#define BUSCON1_CMULT4		1
+
+#define NAND_CON_CE		(1 << 20)
+#define NAND_CON_OUT_CS1	(1 << 10)
+#define NAND_CON_IN_CS1		(1 << 8)
+#define NAND_CON_PRE_P		(1 << 7)
+#define NAND_CON_WP_P		(1 << 6)
+#define NAND_CON_SE_P		(1 << 5)
+#define NAND_CON_CS_P		(1 << 4)
+#define NAND_CON_CSMUX		(1 << 1)
+#define NAND_CON_NANDM		1
+
+static void xway_reset_chip(struct nand_chip *chip)
+{
+	unsigned long nandaddr = (unsigned long) chip->IO_ADDR_W;
+	unsigned long flags;
+
+	nandaddr &= ~NAND_WRITE_ADDR;
+	nandaddr |= NAND_WRITE_CMD;
+
+	/* finish with a reset */
+	spin_lock_irqsave(&ebu_lock, flags);
+	writeb(NAND_WRITE_CMD_RESET, (void __iomem *) nandaddr);
+	while ((ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_WR_C) == 0)
+		;
+	spin_unlock_irqrestore(&ebu_lock, flags);
+}
+
+static void xway_select_chip(struct mtd_info *mtd, int chip)
+{
+
+	switch (chip) {
+	case -1:
+		ltq_ebu_w32_mask(NAND_CON_CE, 0, EBU_NAND_CON);
+		ltq_ebu_w32_mask(NAND_CON_NANDM, 0, EBU_NAND_CON);
+		break;
+	case 0:
+		ltq_ebu_w32_mask(0, NAND_CON_NANDM, EBU_NAND_CON);
+		ltq_ebu_w32_mask(0, NAND_CON_CE, EBU_NAND_CON);
+		break;
+	default:
+		BUG();
+	}
+}
+
+static void xway_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
+{
+	struct nand_chip *this = mtd->priv;
+	unsigned long nandaddr = (unsigned long) this->IO_ADDR_W;
+	unsigned long flags;
+
+	if (ctrl & NAND_CTRL_CHANGE) {
+		nandaddr &= ~(NAND_WRITE_CMD | NAND_WRITE_ADDR);
+		if (ctrl & NAND_CLE)
+			nandaddr |= NAND_WRITE_CMD;
+		else
+			nandaddr |= NAND_WRITE_ADDR;
+		this->IO_ADDR_W = (void __iomem *) nandaddr;
+	}
+
+	if (cmd != NAND_CMD_NONE) {
+		spin_lock_irqsave(&ebu_lock, flags);
+		writeb(cmd, this->IO_ADDR_W);
+		while ((ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_WR_C) == 0)
+			;
+		spin_unlock_irqrestore(&ebu_lock, flags);
+	}
+}
+
+static int xway_dev_ready(struct mtd_info *mtd)
+{
+	return ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_RD;
+}
+
+static unsigned char xway_read_byte(struct mtd_info *mtd)
+{
+	struct nand_chip *this = mtd->priv;
+	unsigned long nandaddr = (unsigned long) this->IO_ADDR_R;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&ebu_lock, flags);
+	ret = ltq_r8((void __iomem *)(nandaddr + NAND_READ_DATA));
+	spin_unlock_irqrestore(&ebu_lock, flags);
+
+	return ret;
+}
+
+static int xway_nand_probe(struct platform_device *pdev)
+{
+	struct nand_chip *this = platform_get_drvdata(pdev);
+	unsigned long nandaddr = (unsigned long) this->IO_ADDR_W;
+	const __be32 *cs = of_get_property(pdev->dev.of_node,
+					"lantiq,cs", NULL);
+	u32 cs_flag = 0;
+
+	/* load our CS from the DT. Either we find a valid 1 or default to 0 */
+	if (cs && (*cs == 1))
+		cs_flag = NAND_CON_IN_CS1 | NAND_CON_OUT_CS1;
+
+	/* setup the EBU to run in NAND mode on our base addr */
+	ltq_ebu_w32(CPHYSADDR(nandaddr)
+		| ADDSEL1_MASK(3) | ADDSEL1_REGEN, EBU_ADDSEL1);
+
+	ltq_ebu_w32(BUSCON1_SETUP | BUSCON1_BCGEN_RES | BUSCON1_WAITWRC2
+		| BUSCON1_WAITRDC2 | BUSCON1_HOLDC1 | BUSCON1_RECOVC1
+		| BUSCON1_CMULT4, LTQ_EBU_BUSCON1);
+
+	ltq_ebu_w32(NAND_CON_NANDM | NAND_CON_CSMUX | NAND_CON_CS_P
+		| NAND_CON_SE_P | NAND_CON_WP_P | NAND_CON_PRE_P
+		| cs_flag, EBU_NAND_CON);
+
+	/* finish with a reset */
+	xway_reset_chip(this);
+
+	return 0;
+}
+
+/* allow users to override the partition in DT using the cmdline */
+static const char *part_probes[] = { "cmdlinepart", "ofpart", NULL };
+
+static struct platform_nand_data xway_nand_data = {
+	.chip = {
+		.nr_chips		= 1,
+		.chip_delay		= 30,
+		.part_probe_types	= part_probes,
+	},
+	.ctrl = {
+		.probe		= xway_nand_probe,
+		.cmd_ctrl	= xway_cmd_ctrl,
+		.dev_ready	= xway_dev_ready,
+		.select_chip	= xway_select_chip,
+		.read_byte	= xway_read_byte,
+	}
+};
+
+/*
+ * Try to find the node inside the DT. If it is available attach out
+ * platform_nand_data
+ */
+static int __init xway_register_nand(void)
+{
+	struct device_node *node;
+	struct platform_device *pdev;
+
+	node = of_find_compatible_node(NULL, NULL, "lantiq,nand-xway");
+	if (!node)
+		return -ENOENT;
+	pdev = of_find_device_by_node(node);
+	if (!pdev)
+		return -EINVAL;
+	pdev->dev.platform_data = &xway_nand_data;
+	of_node_put(node);
+	return 0;
+}
+
+subsys_initcall(xway_register_nand);