Patchwork [v3] MTD: Nand: Add JZ4740 NAND driver

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Submitter Lars-Peter Clausen
Date July 17, 2010, 12:15 p.m.
Message ID <1279368929-21193-1-git-send-email-lars@metafoo.de>
Download mbox | patch
Permalink /patch/59136/
State New
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Comments

Lars-Peter Clausen - July 17, 2010, 12:15 p.m.
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

Changes since v2
- Fix potential deadlock that can happen when the hardware is broken
- Move include file from include/linux/mtd/ to arch/mips/include/asm/mach-jz4740/
- {Enable,Disable} NAND-chip in {probe,remove}
- Supply memory bank address through platform resource
---
 arch/mips/include/asm/mach-jz4740/jz4740_nand.h |   34 ++
 drivers/mtd/nand/Kconfig                        |    6 +
 drivers/mtd/nand/Makefile                       |    1 +
 drivers/mtd/nand/jz4740_nand.c                  |  516 +++++++++++++++++++++++
 4 files changed, 557 insertions(+), 0 deletions(-)
 create mode 100644 arch/mips/include/asm/mach-jz4740/jz4740_nand.h
 create mode 100644 drivers/mtd/nand/jz4740_nand.c
Artem Bityutskiy - July 18, 2010, 4:54 p.m.
On Sat, 2010-07-17 at 14:15 +0200, Lars-Peter Clausen wrote:
> 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
> 

Do you expect this patch to go in via the MTD tree? I guess it might be
better if it was MIPS tree?
Lars-Peter Clausen - July 18, 2010, 5:02 p.m.
Artem Bityutskiy wrote:
> On Sat, 2010-07-17 at 14:15 +0200, Lars-Peter Clausen wrote:
>> 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
>>
> 
> Do you expect this patch to go in via the MTD tree? I guess it might be
> better if it was MIPS tree?

Hi

Yes, letting it go through the MIPS tree is the plan.

- Lars

Patch

diff --git a/arch/mips/include/asm/mach-jz4740/jz4740_nand.h b/arch/mips/include/asm/mach-jz4740/jz4740_nand.h
new file mode 100644
index 0000000..bb5b9a4
--- /dev/null
+++ b/arch/mips/include/asm/mach-jz4740/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 __ASM_MACH_JZ4740_JZ4740_NAND_H__
+#define __ASM_MACH_JZ4740_JZ4740_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
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..67343fc
--- /dev/null
+++ b/drivers/mtd/nand/jz4740_nand.c
@@ -0,0 +1,516 @@ 
+/*
+ *  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/gpio.h>
+
+#include <asm/mach-jz4740/jz4740_nand.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_MEM_ADDR_OFFSET 0x10000
+#define JZ_NAND_MEM_CMD_OFFSET 0x08000
+
+struct jz_nand {
+	struct mtd_info mtd;
+	struct nand_chip chip;
+	void __iomem *base;
+	struct resource *mem;
+
+	void __iomem *bank_base;
+	struct resource *bank_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 = nand->bank_base + JZ_NAND_MEM_ADDR_OFFSET;
+		else if (ctrl & NAND_CLE)
+			chip->IO_ADDR_W = nand->bank_base + JZ_NAND_MEM_CMD_OFFSET;
+		else
+			chip->IO_ADDR_W = nand->bank_base;
+
+		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;
+	unsigned int timeout = 1000;
+	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) && --timeout);
+
+	if (timeout == 0)
+	    return -1;
+
+	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 jz_nand_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;
+	unsigned int timeout = 1000;
+
+	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) && --timeout);
+
+	if (timeout == 0)
+	    return -1;
+
+	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)
+				jz_nand_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 jz_nand_ioremap_resource(struct platform_device *pdev,
+	const char *name, struct resource **res, void __iomem **base)
+{
+	int ret;
+
+	*res = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
+	if (!*res) {
+		dev_err(&pdev->dev, "Failed to get platform %s memory\n", name);
+		ret = -ENXIO;
+		goto err;
+	}
+
+	*res = request_mem_region((*res)->start, resource_size(*res),
+				pdev->name);
+	if (!*res) {
+		dev_err(&pdev->dev, "Failed to request %s memory region\n", name);
+		ret = -EBUSY;
+		goto err;
+	}
+
+	*base = ioremap((*res)->start, resource_size(*res));
+	if (!*base) {
+		dev_err(&pdev->dev, "Failed to ioremap %s memory region\n", name);
+		ret = -EBUSY;
+		goto err_release_mem;
+	}
+
+	return 0;
+
+err_release_mem:
+	release_mem_region((*res)->start, resource_size(*res));
+err:
+	*res = NULL;
+	*base = NULL;
+	return ret;
+}
+
+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;
+	}
+
+	ret = jz_nand_ioremap_resource(pdev, "mmio", &nand->mem, &nand->base);
+	if (ret)
+		goto err_free;
+	ret = jz_nand_ioremap_resource(pdev, "bank", &nand->bank_mem,
+			&nand->bank_base);
+	if (ret)
+		goto err_iounmap_mmio;
+
+	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_mem;
+		}
+	}
+
+	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 = nand->bank_base;
+	chip->IO_ADDR_W = nand->bank_base;
+
+	nand->pdata = pdata;
+	platform_set_drvdata(pdev, nand);
+
+	writel(JZ_NAND_CTRL_ENABLE_CHIP(0), nand->base + JZ_REG_NAND_CTRL);
+
+	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_mem:
+	iounmap(nand->bank_base);
+err_iounmap_mmio:
+	iounmap(nand->base);
+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);
+
+	/* Deassert and disable all chips */
+	writel(0, nand->base + JZ_REG_NAND_CTRL);
+
+	iounmap(nand->bank_base);
+	release_mem_region(nand->bank_mem->start, resource_size(nand->bank_mem));
+	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");