diff mbox

[v2,17/26] MTD: Nand: Add JZ4740 NAND driver

Message ID 1276924111-11158-18-git-send-email-lars@metafoo.de
State New, archived
Headers show

Commit Message

Lars-Peter Clausen June 19, 2010, 5:08 a.m. UTC
This patch adds support for the NAND controller on JZ4740 SoCs.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org

---
Changes since v1
- JZ4740: Remove debug macro
- Fix platform driver remove callback
- Add custom nand read/write callback since we need to support more then 64 ecc
  bytes
---
 drivers/mtd/nand/Kconfig        |    6 +
 drivers/mtd/nand/Makefile       |    1 +
 drivers/mtd/nand/jz4740_nand.c  |  474 +++++++++++++++++++++++++++++++++++++++
 include/linux/mtd/jz4740_nand.h |   34 +++
 4 files changed, 515 insertions(+), 0 deletions(-)
 create mode 100644 drivers/mtd/nand/jz4740_nand.c
 create mode 100644 include/linux/mtd/jz4740_nand.h

Comments

Artem Bityutskiy July 8, 2010, 6:06 a.m. UTC | #1
On Sat, 2010-06-19 at 07:08 +0200, Lars-Peter Clausen wrote:
> diff --git a/include/linux/mtd/jz4740_nand.h b/include/linux/mtd/jz4740_nand.h
> new file mode 100644
> index 0000000..379f9b6
> --- /dev/null
> +++ b/include/linux/mtd/jz4740_nand.h
> @@ -0,0 +1,34 @@
> +/*
> + *  Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
> + *  JZ4740 SoC NAND controller driver
> + *
> + *  This program is free software; you can redistribute	 it and/or modify it
> + *  under  the terms of	 the GNU General  Public License as published by the
> + *  Free Software Foundation;  either version 2 of the	License, or (at your
> + *  option) any later version.
> + *
> + *  You should have received a copy of the  GNU General Public License along
> + *  with this program; if not, write  to the Free Software Foundation, Inc.,
> + *  675 Mass Ave, Cambridge, MA 02139, USA.
> + *
> + */
> +
> +#ifndef __JZ_NAND_H__
> +#define __JZ_NAND_H__
> +
> +#include <linux/mtd/nand.h>
> +#include <linux/mtd/partitions.h>
> +
> +struct jz_nand_platform_data {
> +	int			num_partitions;
> +	struct mtd_partition	*partitions;
> +
> +	struct nand_ecclayout	*ecc_layout;
> +
> +	unsigned int busy_gpio;
> +
> +	void (*ident_callback)(struct platform_device *, struct nand_chip *,
> +				struct mtd_partition **, int *num_partitions);
> +};
> +
> +#endif

Do you really have to add your platform data strucutre to
"inlculde/mtd" ? That is quite global namespace, and ideally only things
like user-space interface and "public" interface of the MTD subsystem
should live there.

Can you keep this somewhere in mips architecture directory?
Artem Bityutskiy July 8, 2010, 1:19 p.m. UTC | #2
On Thu, 2010-07-08 at 15:20 +0200, Lars-Peter Clausen wrote:
> On the other hand I'm wondering where on would put headers for non platform specific
> drivers?

If we are talking about MTD, then drivers/mtd ?
Lars-Peter Clausen July 8, 2010, 1:20 p.m. UTC | #3
Artem Bityutskiy wrote:
> On Sat, 2010-06-19 at 07:08 +0200, Lars-Peter Clausen wrote:
>> diff --git a/include/linux/mtd/jz4740_nand.h b/include/linux/mtd/jz4740_nand.h
>> new file mode 100644
>> index 0000000..379f9b6
>> --- /dev/null
>> +++ b/include/linux/mtd/jz4740_nand.h
>> @@ -0,0 +1,34 @@
>> +/*
>> + *  Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
>> + *  JZ4740 SoC NAND controller driver
>> + *
>> + *  This program is free software; you can redistribute	 it and/or modify it
>> + *  under  the terms of	 the GNU General  Public License as published by the
>> + *  Free Software Foundation;  either version 2 of the	License, or (at your
>> + *  option) any later version.
>> + *
>> + *  You should have received a copy of the  GNU General Public License along
>> + *  with this program; if not, write  to the Free Software Foundation, Inc.,
>> + *  675 Mass Ave, Cambridge, MA 02139, USA.
>> + *
>> + */
>> +
>> +#ifndef __JZ_NAND_H__
>> +#define __JZ_NAND_H__
>> +
>> +#include <linux/mtd/nand.h>
>> +#include <linux/mtd/partitions.h>
>> +
>> +struct jz_nand_platform_data {
>> +	int			num_partitions;
>> +	struct mtd_partition	*partitions;
>> +
>> +	struct nand_ecclayout	*ecc_layout;
>> +
>> +	unsigned int busy_gpio;
>> +
>> +	void (*ident_callback)(struct platform_device *, struct nand_chip *,
>> +				struct mtd_partition **, int *num_partitions);
>> +};
>> +
>> +#endif
> 
> Do you really have to add your platform data strucutre to
> "inlculde/mtd" ? That is quite global namespace, and ideally only things
> like user-space interface and "public" interface of the MTD subsystem
> should live there.
> 
> Can you keep this somewhere in mips architecture directory?

Hi

Hm, ok, I see. I'll move it to arch/mips/include/asm/mach-jz4740/ then.
But I guess I should move the headers for all the other jz4740 driver to the same
directory as well.

On the other hand I'm wondering where on would put headers for non platform specific
drivers?

- Lars
Lars-Peter Clausen July 8, 2010, 2:02 p.m. UTC | #4
Artem Bityutskiy wrote:
> On Thu, 2010-07-08 at 15:20 +0200, Lars-Peter Clausen wrote:
>> On the other hand I'm wondering where on would put headers for non platform specific
>> drivers?
> 
> If we are talking about MTD, then drivers/mtd ?
> 
No, what I meant was header defining platform data structs and such.
And what I wanted to get at is an answer to why driver header files are put in
different directories while the driver files themselves are all keep in the same
directory. (drivers of the same subsystem that is)

- Lars
Artem Bityutskiy July 8, 2010, 2:14 p.m. UTC | #5
On Thu, 2010-07-08 at 16:02 +0200, Lars-Peter Clausen wrote:
> Artem Bityutskiy wrote:
> > On Thu, 2010-07-08 at 15:20 +0200, Lars-Peter Clausen wrote:
> >> On the other hand I'm wondering where on would put headers for non platform specific
> >> drivers?
> > 
> > If we are talking about MTD, then drivers/mtd ?
> > 
> No, what I meant was header defining platform data structs and such.
> And what I wanted to get at is an answer to why driver header files are put in
> different directories while the driver files themselves are all keep in the same
> directory. (drivers of the same subsystem that is)

To be frank I do not know, I did not look at the whole picture, just at
the MTD part :-)
diff mbox

Patch

diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index ffc3720..362d177 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -526,4 +526,10 @@  config MTD_NAND_NUC900
 	  This enables the driver for the NAND Flash on evaluation board based
 	  on w90p910 / NUC9xx.
 
+config MTD_NAND_JZ4740
+	tristate "Support for JZ4740 SoC NAND controller"
+	depends on MACH_JZ4740
+	help
+		Enables support for NAND Flash on JZ4740 SoC based boards.
+
 endif # MTD_NAND
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index e8ab884..ac83dcd 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -46,5 +46,6 @@  obj-$(CONFIG_MTD_NAND_NOMADIK)		+= nomadik_nand.o
 obj-$(CONFIG_MTD_NAND_BCM_UMI)		+= bcm_umi_nand.o nand_bcm_umi.o
 obj-$(CONFIG_MTD_NAND_MPC5121_NFC)	+= mpc5121_nfc.o
 obj-$(CONFIG_MTD_NAND_RICOH)		+= r852.o
+obj-$(CONFIG_MTD_NAND_JZ4740)		+= jz4740_nand.o
 
 nand-objs := nand_base.o nand_bbt.o
diff --git a/drivers/mtd/nand/jz4740_nand.c b/drivers/mtd/nand/jz4740_nand.c
new file mode 100644
index 0000000..8c55f8a
--- /dev/null
+++ b/drivers/mtd/nand/jz4740_nand.c
@@ -0,0 +1,474 @@ 
+/*
+ *  Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
+ *  JZ4740 SoC NAND controller driver
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under  the terms of the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/partitions.h>
+
+#include <linux/mtd/jz4740_nand.h>
+#include <linux/gpio.h>
+
+#define JZ_REG_NAND_CTRL	0x50
+#define JZ_REG_NAND_ECC_CTRL	0x100
+#define JZ_REG_NAND_DATA	0x104
+#define JZ_REG_NAND_PAR0	0x108
+#define JZ_REG_NAND_PAR1	0x10C
+#define JZ_REG_NAND_PAR2	0x110
+#define JZ_REG_NAND_IRQ_STAT	0x114
+#define JZ_REG_NAND_IRQ_CTRL	0x118
+#define JZ_REG_NAND_ERR(x)	(0x11C + (x << 2))
+
+#define JZ_NAND_ECC_CTRL_PAR_READY	BIT(4)
+#define JZ_NAND_ECC_CTRL_ENCODING	BIT(3)
+#define JZ_NAND_ECC_CTRL_RS		BIT(2)
+#define JZ_NAND_ECC_CTRL_RESET		BIT(1)
+#define JZ_NAND_ECC_CTRL_ENABLE		BIT(0)
+
+#define JZ_NAND_STATUS_ERR_COUNT	(BIT(31) | BIT(30) | BIT(29))
+#define JZ_NAND_STATUS_PAD_FINISH	BIT(4)
+#define JZ_NAND_STATUS_DEC_FINISH	BIT(3)
+#define JZ_NAND_STATUS_ENC_FINISH	BIT(2)
+#define JZ_NAND_STATUS_UNCOR_ERROR	BIT(1)
+#define JZ_NAND_STATUS_ERROR		BIT(0)
+
+#define JZ_NAND_CTRL_ENABLE_CHIP(x) BIT(x << 1)
+#define JZ_NAND_CTRL_ASSERT_CHIP(x) BIT((x << 1) + 1)
+
+#define JZ_NAND_DATA_ADDR ((void __iomem *)0xB8000000)
+#define JZ_NAND_CMD_ADDR (JZ_NAND_DATA_ADDR + 0x8000)
+#define JZ_NAND_ADDR_ADDR (JZ_NAND_DATA_ADDR + 0x10000)
+
+struct jz_nand {
+	struct mtd_info mtd;
+	struct nand_chip chip;
+	void __iomem *base;
+	struct resource *mem;
+
+	struct jz_nand_platform_data *pdata;
+	bool is_reading;
+};
+
+static inline struct jz_nand *mtd_to_jz_nand(struct mtd_info *mtd)
+{
+	return container_of(mtd, struct jz_nand, mtd);
+}
+
+static void jz_nand_cmd_ctrl(struct mtd_info *mtd, int dat, unsigned int ctrl)
+{
+	struct jz_nand *nand = mtd_to_jz_nand(mtd);
+	struct nand_chip *chip = mtd->priv;
+	uint32_t reg;
+
+	if (ctrl & NAND_CTRL_CHANGE) {
+		BUG_ON((ctrl & NAND_ALE) && (ctrl & NAND_CLE));
+		if (ctrl & NAND_ALE)
+			chip->IO_ADDR_W = JZ_NAND_ADDR_ADDR;
+		else if (ctrl & NAND_CLE)
+			chip->IO_ADDR_W = JZ_NAND_CMD_ADDR;
+		else
+			chip->IO_ADDR_W = JZ_NAND_DATA_ADDR;
+
+		reg = readl(nand->base + JZ_REG_NAND_CTRL);
+		if (ctrl & NAND_NCE)
+			reg |= JZ_NAND_CTRL_ASSERT_CHIP(0);
+		else
+			reg &= ~JZ_NAND_CTRL_ASSERT_CHIP(0);
+		writel(reg, nand->base + JZ_REG_NAND_CTRL);
+	}
+	if (dat != NAND_CMD_NONE)
+		writeb(dat, chip->IO_ADDR_W);
+}
+
+static int jz_nand_dev_ready(struct mtd_info *mtd)
+{
+	struct jz_nand *nand = mtd_to_jz_nand(mtd);
+	return gpio_get_value_cansleep(nand->pdata->busy_gpio);
+}
+
+static void jz_nand_hwctl(struct mtd_info *mtd, int mode)
+{
+	struct jz_nand *nand = mtd_to_jz_nand(mtd);
+	uint32_t reg;
+
+	writel(0, nand->base + JZ_REG_NAND_IRQ_STAT);
+	reg = readl(nand->base + JZ_REG_NAND_ECC_CTRL);
+
+	reg |= JZ_NAND_ECC_CTRL_RESET;
+	reg |= JZ_NAND_ECC_CTRL_ENABLE;
+	reg |= JZ_NAND_ECC_CTRL_RS;
+
+	switch (mode) {
+	case NAND_ECC_READ:
+		reg &= ~JZ_NAND_ECC_CTRL_ENCODING;
+		nand->is_reading = true;
+		break;
+	case NAND_ECC_WRITE:
+		reg |= JZ_NAND_ECC_CTRL_ENCODING;
+		nand->is_reading = false;
+		break;
+	default:
+		break;
+	}
+
+	writel(reg, nand->base + JZ_REG_NAND_ECC_CTRL);
+}
+
+static int jz_nand_calculate_ecc_rs(struct mtd_info *mtd, const uint8_t *dat,
+	uint8_t *ecc_code)
+{
+	struct jz_nand *nand = mtd_to_jz_nand(mtd);
+	uint32_t reg, status;
+	int i;
+	static uint8_t empty_block_ecc[] = {0xcd, 0x9d, 0x90, 0x58, 0xf4,
+						0x8b, 0xff, 0xb7, 0x6f};
+
+	if (nand->is_reading)
+		return 0;
+
+	do {
+		status = readl(nand->base + JZ_REG_NAND_IRQ_STAT);
+	} while (!(status & JZ_NAND_STATUS_ENC_FINISH));
+
+	reg = readl(nand->base + JZ_REG_NAND_ECC_CTRL);
+	reg &= ~JZ_NAND_ECC_CTRL_ENABLE;
+	writel(reg, nand->base + JZ_REG_NAND_ECC_CTRL);
+
+	for (i = 0; i < 9; ++i)
+		ecc_code[i] = readb(nand->base + JZ_REG_NAND_PAR0 + i);
+
+	/* If the written data is completly 0xff, we also want to write 0xff as
+	 * ecc, otherwise we will get in trouble when doing subpage writes. */
+	if (memcmp(ecc_code, empty_block_ecc, 9) == 0)
+		memset(ecc_code, 0xff, 9);
+
+	return 0;
+}
+
+static void correct_data(uint8_t *dat, int index, int mask)
+{
+	int offset = index & 0x7;
+	uint16_t data;
+
+	index += (index >> 3);
+
+	data = dat[index];
+	data |= dat[index+1] << 8;
+
+	mask ^= (data >> offset) & 0x1ff;
+	data &= ~(0x1ff << offset);
+	data |= (mask << offset);
+
+	dat[index] = data & 0xff;
+	dat[index+1] = (data >> 8) & 0xff;
+}
+
+static int jz_nand_correct_ecc_rs(struct mtd_info *mtd, uint8_t *dat,
+	uint8_t *read_ecc, uint8_t *calc_ecc)
+{
+	struct jz_nand *nand = mtd_to_jz_nand(mtd);
+	int i, error_count, index;
+	uint32_t reg, status, error;
+	uint32_t t;
+
+	t = read_ecc[0];
+
+	if (t == 0xff) {
+		for (i = 1; i < 9; ++i)
+			t &= read_ecc[i];
+
+		t &= dat[0];
+		t &= dat[nand->chip.ecc.size / 2];
+		t &= dat[nand->chip.ecc.size - 1];
+
+		if (t == 0xff) {
+			for (i = 1; i < nand->chip.ecc.size - 1; ++i)
+				t &= dat[i];
+			if (t == 0xff)
+				return 0;
+		}
+	}
+
+	for (i = 0; i < 9; ++i)
+		writeb(read_ecc[i], nand->base + JZ_REG_NAND_PAR0 + i);
+
+	reg = readl(nand->base + JZ_REG_NAND_ECC_CTRL);
+	reg |= JZ_NAND_ECC_CTRL_PAR_READY;
+	writel(reg, nand->base + JZ_REG_NAND_ECC_CTRL);
+
+	do {
+		status = readl(nand->base + JZ_REG_NAND_IRQ_STAT);
+	} while (!(status & JZ_NAND_STATUS_DEC_FINISH));
+
+	reg = readl(nand->base + JZ_REG_NAND_ECC_CTRL);
+	reg &= ~JZ_NAND_ECC_CTRL_ENABLE;
+	writel(reg, nand->base + JZ_REG_NAND_ECC_CTRL);
+
+	if (status & JZ_NAND_STATUS_ERROR) {
+		if (status & JZ_NAND_STATUS_UNCOR_ERROR)
+			return -1;
+
+		error_count = (status & JZ_NAND_STATUS_ERR_COUNT) >> 29;
+
+		for (i = 0; i < error_count; ++i) {
+			error = readl(nand->base + JZ_REG_NAND_ERR(i));
+			index = ((error >> 16) & 0x1ff) - 1;
+			if (index >= 0 && index < 512)
+				correct_data(dat, index, error & 0x1ff);
+		}
+
+		return error_count;
+	}
+
+	return 0;
+}
+
+
+/* Copy paste of nand_read_page_hwecc_oob_first except for different eccpos
+ * handling. The ecc area is for 4k chips 72 bytes long and thus does not fit
+ * into the eccpos array. */
+static int jz_nand_read_page_hwecc_oob_first(struct mtd_info *mtd,
+	struct nand_chip *chip, uint8_t *buf, int page)
+{
+	int i, eccsize = chip->ecc.size;
+	int eccbytes = chip->ecc.bytes;
+	int eccsteps = chip->ecc.steps;
+	uint8_t *p = buf;
+	unsigned int ecc_offset = chip->page_shift;
+
+	/* Read the OOB area first */
+	chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
+	chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
+	chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
+
+	for (i = ecc_offset; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
+		int stat;
+
+		chip->ecc.hwctl(mtd, NAND_ECC_READ);
+		chip->read_buf(mtd, p, eccsize);
+
+		stat = chip->ecc.correct(mtd, p, &chip->oob_poi[i], NULL);
+		if (stat < 0)
+			mtd->ecc_stats.failed++;
+		else
+			mtd->ecc_stats.corrected += stat;
+	}
+	return 0;
+}
+
+/* Copy-and-paste of nand_write_page_hwecc with different eccpos handling. */
+static void jz_nand_write_page_hwecc(struct mtd_info *mtd,
+	struct nand_chip *chip, const uint8_t *buf)
+{
+	int i, eccsize = chip->ecc.size;
+	int eccbytes = chip->ecc.bytes;
+	int eccsteps = chip->ecc.steps;
+	const uint8_t *p = buf;
+	unsigned int ecc_offset = chip->page_shift;
+
+	for (i = ecc_offset; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
+		chip->ecc.hwctl(mtd, NAND_ECC_WRITE);
+		chip->write_buf(mtd, p, eccsize);
+		chip->ecc.calculate(mtd, p, &chip->oob_poi[i]);
+	}
+
+	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
+}
+
+#ifdef CONFIG_MTD_CMDLINE_PARTS
+static const char *part_probes[] = {"cmdline", NULL};
+#endif
+
+static int __devinit jz_nand_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct jz_nand *nand;
+	struct nand_chip *chip;
+	struct mtd_info *mtd;
+	struct jz_nand_platform_data *pdata = pdev->dev.platform_data;
+#ifdef CONFIG_MTD_PARTITIONS
+	struct mtd_partition *partition_info;
+	int num_partitions = 0;
+#endif
+
+	nand = kzalloc(sizeof(*nand), GFP_KERNEL);
+	if (!nand) {
+		dev_err(&pdev->dev, "Failed to allocate device structure.\n");
+		return -ENOMEM;
+	}
+
+	nand->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!nand->mem) {
+		dev_err(&pdev->dev, "Failed to get platform mmio memory\n");
+		ret = -ENOENT;
+		goto err_free;
+	}
+
+	nand->mem = request_mem_region(nand->mem->start,
+					resource_size(nand->mem), pdev->name);
+	if (!nand->mem) {
+		dev_err(&pdev->dev, "Failed to request mmio memory region\n");
+		ret = -EBUSY;
+		goto err_free;
+	}
+
+	nand->base = ioremap(nand->mem->start, resource_size(nand->mem));
+	if (!nand->base) {
+		dev_err(&pdev->dev, "Failed to ioremap mmio memory region\n");
+		ret = -EBUSY;
+		goto err_release_mem;
+	}
+
+	if (pdata && gpio_is_valid(pdata->busy_gpio)) {
+		ret = gpio_request(pdata->busy_gpio, "NAND busy pin");
+		if (ret) {
+			dev_err(&pdev->dev,
+				"Failed to request busy gpio %d: %d\n",
+				pdata->busy_gpio, ret);
+			goto err_iounmap;
+		}
+	}
+
+	mtd		= &nand->mtd;
+	chip		= &nand->chip;
+	mtd->priv	= chip;
+	mtd->owner	= THIS_MODULE;
+	mtd->name	= "jz4740-nand";
+
+	chip->ecc.hwctl		= jz_nand_hwctl;
+	chip->ecc.calculate	= jz_nand_calculate_ecc_rs;
+	chip->ecc.correct	= jz_nand_correct_ecc_rs;
+	chip->ecc.mode		= NAND_ECC_HW_OOB_FIRST;
+	chip->ecc.size		= 512;
+	chip->ecc.bytes		= 9;
+
+	chip->ecc.read_page	= jz_nand_read_page_hwecc_oob_first;
+	chip->ecc.write_page	= jz_nand_write_page_hwecc;
+
+	if (pdata)
+		chip->ecc.layout = pdata->ecc_layout;
+
+	chip->chip_delay = 50;
+	chip->cmd_ctrl = jz_nand_cmd_ctrl;
+
+	if (pdata && gpio_is_valid(pdata->busy_gpio))
+		chip->dev_ready = jz_nand_dev_ready;
+
+	chip->IO_ADDR_R = JZ_NAND_DATA_ADDR;
+	chip->IO_ADDR_W = JZ_NAND_DATA_ADDR;
+
+	nand->pdata = pdata;
+	platform_set_drvdata(pdev, nand);
+
+	ret = nand_scan_ident(mtd, 1, NULL);
+	if (ret) {
+		dev_err(&pdev->dev,  "Failed to scan nand\n");
+		goto err_gpio_free;
+	}
+
+	if (pdata && pdata->ident_callback) {
+		pdata->ident_callback(pdev, chip, &pdata->partitions,
+					&pdata->num_partitions);
+	}
+
+	ret = nand_scan_tail(mtd);
+	if (ret) {
+		dev_err(&pdev->dev,  "Failed to scan nand\n");
+		goto err_gpio_free;
+	}
+
+#ifdef CONFIG_MTD_PARTITIONS
+#ifdef CONFIG_MTD_CMDLINE_PARTS
+	num_partitions = parse_mtd_partitions(mtd, part_probes,
+						&partition_info, 0);
+#endif
+	if (num_partitions <= 0 && pdata) {
+		num_partitions = pdata->num_partitions;
+		partition_info = pdata->partitions;
+	}
+
+	if (num_partitions > 0)
+		ret = add_mtd_partitions(mtd, partition_info, num_partitions);
+	else
+#endif
+	ret = add_mtd_device(mtd);
+
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to add mtd device\n");
+		goto err_nand_release;
+	}
+
+	dev_info(&pdev->dev, "Successfully registered JZ4740 NAND driver\n");
+
+	return 0;
+err_nand_release:
+	nand_release(&nand->mtd);
+err_gpio_free:
+	platform_set_drvdata(pdev, NULL);
+	gpio_free(pdata->busy_gpio);
+err_iounmap:
+	iounmap(nand->base);
+err_release_mem:
+	release_mem_region(nand->mem->start, resource_size(nand->mem));
+err_free:
+	kfree(nand);
+	return ret;
+}
+
+static int __devexit jz_nand_remove(struct platform_device *pdev)
+{
+	struct jz_nand *nand = platform_get_drvdata(pdev);
+
+	nand_release(&nand->mtd);
+
+	iounmap(nand->base);
+	release_mem_region(nand->mem->start, resource_size(nand->mem));
+
+	platform_set_drvdata(pdev, NULL);
+	kfree(nand);
+
+	return 0;
+}
+
+struct platform_driver jz_nand_driver = {
+	.probe = jz_nand_probe,
+	.remove = __devexit_p(jz_nand_remove),
+	.driver = {
+		.name = "jz4740-nand",
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init jz_nand_init(void)
+{
+	return platform_driver_register(&jz_nand_driver);
+}
+module_init(jz_nand_init);
+
+static void __exit jz_nand_exit(void)
+{
+	platform_driver_unregister(&jz_nand_driver);
+}
+module_exit(jz_nand_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("NAND controller driver for JZ4740 SoC");
+MODULE_ALIAS("platform:jz4740-nand");
diff --git a/include/linux/mtd/jz4740_nand.h b/include/linux/mtd/jz4740_nand.h
new file mode 100644
index 0000000..379f9b6
--- /dev/null
+++ b/include/linux/mtd/jz4740_nand.h
@@ -0,0 +1,34 @@ 
+/*
+ *  Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
+ *  JZ4740 SoC NAND controller driver
+ *
+ *  This program is free software; you can redistribute	 it and/or modify it
+ *  under  the terms of	 the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the	License, or (at your
+ *  option) any later version.
+ *
+ *  You should have received a copy of the  GNU General Public License along
+ *  with this program; if not, write  to the Free Software Foundation, Inc.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#ifndef __JZ_NAND_H__
+#define __JZ_NAND_H__
+
+#include <linux/mtd/nand.h>
+#include <linux/mtd/partitions.h>
+
+struct jz_nand_platform_data {
+	int			num_partitions;
+	struct mtd_partition	*partitions;
+
+	struct nand_ecclayout	*ecc_layout;
+
+	unsigned int busy_gpio;
+
+	void (*ident_callback)(struct platform_device *, struct nand_chip *,
+				struct mtd_partition **, int *num_partitions);
+};
+
+#endif