[MTD] [NAND] davinci_nand driver

This is a device driver for the NAND flash controller found on the various
DaVinci family chips.  It handles up to four SoC chipselects, and some
flavors of secondary chipselect (e.g.  based on upper bits of the address
bus) as used with some multichip packages.  (Including the 2 GiB chips
used on some TI devel boards.)

The 1-bit ECC hardware is supported (3 bytes ECC per 512 bytes data); but
not yet the newer 4-bit ECC (10 bytes ECC per 512 bytes data), as
available on chips like the DM355 or OMAP-L137 and needed with the more
error-prone MLC NAND chips.

This is a cleaned-up version of code that's been in use for several years
now; sanity checked with the new drivers/mtd/tests.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Sudhakar Rajashekhara <sudhakar.raj@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

4 files changed, 672 insertions, 0 deletions

diff --git a/arch/arm/mach-davinci/include/mach/nand.h b/arch/arm/mach-davinci/include/mach/nand.h
new file mode 100644
index 000000000000..aa482841270b
--- /dev/null
+++ b/arch/arm/mach-davinci/include/mach/nand.h
@@ -0,0 +1,80 @@
+/*
+ * mach-davinci/nand.h
+ *
+ * Copyright © 2006 Texas Instruments.
+ *
+ * Ported to 2.6.23 Copyright © 2008 by
+ *   Sander Huijsen <Shuijsen@optelecom-nkf.com>
+ *   Troy Kisky <troy.kisky@boundarydevices.com>
+ *   Dirk Behme <Dirk.Behme@gmail.com>
+ *
+ * --------------------------------------------------------------------------
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * 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 __ARCH_ARM_DAVINCI_NAND_H
+#define __ARCH_ARM_DAVINCI_NAND_H
+
+#include <linux/mtd/nand.h>
+
+#define NRCSR_OFFSET		0x00
+#define AWCCR_OFFSET		0x04
+#define A1CR_OFFSET		0x10
+#define NANDFCR_OFFSET		0x60
+#define NANDFSR_OFFSET		0x64
+#define NANDF1ECC_OFFSET	0x70
+
+/* 4-bit ECC syndrome registers */
+#define NAND_4BIT_ECC_LOAD_OFFSET	0xbc
+#define NAND_4BIT_ECC1_OFFSET		0xc0
+#define NAND_4BIT_ECC2_OFFSET		0xc4
+#define NAND_4BIT_ECC3_OFFSET		0xc8
+#define NAND_4BIT_ECC4_OFFSET		0xcc
+#define NAND_ERR_ADD1_OFFSET		0xd0
+#define NAND_ERR_ADD2_OFFSET		0xd4
+#define NAND_ERR_ERRVAL1_OFFSET		0xd8
+#define NAND_ERR_ERRVAL2_OFFSET		0xdc
+
+/* NOTE:  boards don't need to use these address bits
+ * for ALE/CLE unless they support booting from NAND.
+ * They're used unless platform data overrides them.
+ */
+#define	MASK_ALE		0x08
+#define	MASK_CLE		0x10
+
+struct davinci_nand_pdata {		/* platform_data */
+	uint32_t		mask_ale;
+	uint32_t		mask_cle;
+
+	/* for packages using two chipselects */
+	uint32_t		mask_chipsel;
+
+	/* board's default static partition info */
+	struct mtd_partition	*parts;
+	unsigned		nr_parts;
+
+	/* none  == NAND_ECC_NONE (strongly *not* advised!!)
+	 * soft  == NAND_ECC_SOFT
+	 * 1-bit == NAND_ECC_HW
+	 * 4-bit == NAND_ECC_HW_SYNDROME (not on all chips)
+	 */
+	nand_ecc_modes_t	ecc_mode;
+
+	/* e.g. NAND_BUSWIDTH_16 or NAND_USE_FLASH_BBT */
+	unsigned		options;
+};
+
+#endif	/* __ARCH_ARM_DAVINCI_NAND_H */
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 8b12e6e109d3..30d6fbc30c35 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -427,4 +427,11 @@ config MTD_NAND_SH_FLCTL
 	  Several Renesas SuperH CPU has FLCTL. This option enables support
 	  for NAND Flash using FLCTL. This driver support SH7723.
 
+config MTD_NAND_DAVINCI
+        tristate "Support NAND on DaVinci SoC"
+        depends on ARCH_DAVINCI
+        help
+	  Enable the driver for NAND flash chips on Texas Instruments
+	  DaVinci processors.
+
 endif # MTD_NAND
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index b661586afbfc..26dc0bef68ae 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_MTD_NAND_AU1550)		+= au1550nd.o
 obj-$(CONFIG_MTD_NAND_BF5XX)		+= bf5xx_nand.o
 obj-$(CONFIG_MTD_NAND_PPCHAMELEONEVB)	+= ppchameleonevb.o
 obj-$(CONFIG_MTD_NAND_S3C2410)		+= s3c2410.o
+obj-$(CONFIG_MTD_NAND_DAVINCI)		+= davinci_nand.o
 obj-$(CONFIG_MTD_NAND_DISKONCHIP)	+= diskonchip.o
 obj-$(CONFIG_MTD_NAND_H1900)		+= h1910.o
 obj-$(CONFIG_MTD_NAND_RTC_FROM4)	+= rtc_from4.o
diff --git a/drivers/mtd/nand/davinci_nand.c b/drivers/mtd/nand/davinci_nand.c
new file mode 100644
index 000000000000..4bedd8dec61e
--- /dev/null
+++ b/drivers/mtd/nand/davinci_nand.c
@@ -0,0 +1,584 @@
+/*
+ * davinci_nand.c - NAND Flash Driver for DaVinci family chips
+ *
+ * Copyright © 2006 Texas Instruments.
+ *
+ * Port to 2.6.23 Copyright © 2008 by:
+ *   Sander Huijsen <Shuijsen@optelecom-nkf.com>
+ *   Troy Kisky <troy.kisky@boundarydevices.com>
+ *   Dirk Behme <Dirk.Behme@gmail.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * 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/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/partitions.h>
+
+#include <mach/cpu.h>
+#include <mach/nand.h>
+
+#include <asm/mach-types.h>
+
+
+#ifdef CONFIG_MTD_PARTITIONS
+static inline int mtd_has_partitions(void) { return 1; }
+#else
+static inline int mtd_has_partitions(void) { return 0; }
+#endif
+
+#ifdef CONFIG_MTD_CMDLINE_PARTS
+static inline int mtd_has_cmdlinepart(void) { return 1; }
+#else
+static inline int mtd_has_cmdlinepart(void) { return 0; }
+#endif
+
+
+/*
+ * This is a device driver for the NAND flash controller found on the
+ * various DaVinci family chips.  It handles up to four SoC chipselects,
+ * and some flavors of secondary chipselect (e.g. based on A12) as used
+ * with multichip packages.
+ *
+ * The 1-bit ECC hardware is supported, but not yet the newer 4-bit ECC
+ * available on chips like the DM355 and OMAP-L137 and needed with the
+ * more error-prone MLC NAND chips.
+ *
+ * This driver assumes EM_WAIT connects all the NAND devices' RDY/nBUSY
+ * outputs in a "wire-AND" configuration, with no per-chip signals.
+ */
+struct davinci_nand_info {
+	struct mtd_info		mtd;
+	struct nand_chip	chip;
+
+	struct device		*dev;
+	struct clk		*clk;
+	bool			partitioned;
+
+	void __iomem		*base;
+	void __iomem		*vaddr;
+
+	uint32_t		ioaddr;
+	uint32_t		current_cs;
+
+	uint32_t		mask_chipsel;
+	uint32_t		mask_ale;
+	uint32_t		mask_cle;
+
+	uint32_t		core_chipsel;
+};
+
+static DEFINE_SPINLOCK(davinci_nand_lock);
+
+#define to_davinci_nand(m) container_of(m, struct davinci_nand_info, mtd)
+
+
+static inline unsigned int davinci_nand_readl(struct davinci_nand_info *info,
+		int offset)
+{
+	return __raw_readl(info->base + offset);
+}
+
+static inline void davinci_nand_writel(struct davinci_nand_info *info,
+		int offset, unsigned long value)
+{
+	__raw_writel(value, info->base + offset);
+}
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * Access to hardware control lines:  ALE, CLE, secondary chipselect.
+ */
+
+static void nand_davinci_hwcontrol(struct mtd_info *mtd, int cmd,
+				   unsigned int ctrl)
+{
+	struct davinci_nand_info	*info = to_davinci_nand(mtd);
+	uint32_t			addr = info->current_cs;
+	struct nand_chip		*nand = mtd->priv;
+
+	/* Did the control lines change? */
+	if (ctrl & NAND_CTRL_CHANGE) {
+		if ((ctrl & NAND_CTRL_CLE) == NAND_CTRL_CLE)
+			addr |= info->mask_cle;
+		else if ((ctrl & NAND_CTRL_ALE) == NAND_CTRL_ALE)
+			addr |= info->mask_ale;
+
+		nand->IO_ADDR_W = (void __iomem __force *)addr;
+	}
+
+	if (cmd != NAND_CMD_NONE)
+		iowrite8(cmd, nand->IO_ADDR_W);
+}
+
+static void nand_davinci_select_chip(struct mtd_info *mtd, int chip)
+{
+	struct davinci_nand_info	*info = to_davinci_nand(mtd);
+	uint32_t			addr = info->ioaddr;
+
+	/* maybe kick in a second chipselect */
+	if (chip > 0)
+		addr |= info->mask_chipsel;
+	info->current_cs = addr;
+
+	info->chip.IO_ADDR_W = (void __iomem __force *)addr;
+	info->chip.IO_ADDR_R = info->chip.IO_ADDR_W;
+}
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * 1-bit hardware ECC ... context maintained for each core chipselect
+ */
+
+static inline uint32_t nand_davinci_readecc_1bit(struct mtd_info *mtd)
+{
+	struct davinci_nand_info *info = to_davinci_nand(mtd);
+
+	return davinci_nand_readl(info, NANDF1ECC_OFFSET
+			+ 4 * info->core_chipsel);
+}
+
+static void nand_davinci_hwctl_1bit(struct mtd_info *mtd, int mode)
+{
+	struct davinci_nand_info *info;
+	uint32_t nandcfr;
+	unsigned long flags;
+
+	info = to_davinci_nand(mtd);
+
+	/* Reset ECC hardware */
+	nand_davinci_readecc_1bit(mtd);
+
+	spin_lock_irqsave(&davinci_nand_lock, flags);
+
+	/* Restart ECC hardware */
+	nandcfr = davinci_nand_readl(info, NANDFCR_OFFSET);
+	nandcfr |= BIT(8 + info->core_chipsel);
+	davinci_nand_writel(info, NANDFCR_OFFSET, nandcfr);
+
+	spin_unlock_irqrestore(&davinci_nand_lock, flags);
+}
+
+/*
+ * Read hardware ECC value and pack into three bytes
+ */
+static int nand_davinci_calculate_1bit(struct mtd_info *mtd,
+				      const u_char *dat, u_char *ecc_code)
+{
+	unsigned int ecc_val = nand_davinci_readecc_1bit(mtd);
+	unsigned int ecc24 = (ecc_val & 0x0fff) | ((ecc_val & 0x0fff0000) >> 4);
+
+	/* invert so that erased block ecc is correct */
+	ecc24 = ~ecc24;
+	ecc_code[0] = (u_char)(ecc24);
+	ecc_code[1] = (u_char)(ecc24 >> 8);
+	ecc_code[2] = (u_char)(ecc24 >> 16);
+
+	return 0;
+}
+
+static int nand_davinci_correct_1bit(struct mtd_info *mtd, u_char *dat,
+				     u_char *read_ecc, u_char *calc_ecc)
+{
+	struct nand_chip *chip = mtd->priv;
+	uint32_t eccNand = read_ecc[0] | (read_ecc[1] << 8) |
+					  (read_ecc[2] << 16);
+	uint32_t eccCalc = calc_ecc[0] | (calc_ecc[1] << 8) |
+					  (calc_ecc[2] << 16);
+	uint32_t diff = eccCalc ^ eccNand;
+
+	if (diff) {
+		if ((((diff >> 12) ^ diff) & 0xfff) == 0xfff) {
+			/* Correctable error */
+			if ((diff >> (12 + 3)) < chip->ecc.size) {
+				dat[diff >> (12 + 3)] ^= BIT((diff >> 12) & 7);
+				return 1;
+			} else {
+				return -1;
+			}
+		} else if (!(diff & (diff - 1))) {
+			/* Single bit ECC error in the ECC itself,
+			 * nothing to fix */
+			return 1;
+		} else {
+			/* Uncorrectable error */
+			return -1;
+		}
+
+	}
+	return 0;
+}
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * NOTE:  NAND boot requires ALE == EM_A[1], CLE == EM_A[2], so that's
+ * how these chips are normally wired.  This translates to both 8 and 16
+ * bit busses using ALE == BIT(3) in byte addresses, and CLE == BIT(4).
+ *
+ * For now we assume that configuration, or any other one which ignores
+ * the two LSBs for NAND access ... so we can issue 32-bit reads/writes
+ * and have that transparently morphed into multiple NAND operations.
+ */
+static void nand_davinci_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
+{
+	struct nand_chip *chip = mtd->priv;
+
+	if ((0x03 & ((unsigned)buf)) == 0 && (0x03 & len) == 0)
+		ioread32_rep(chip->IO_ADDR_R, buf, len >> 2);
+	else if ((0x01 & ((unsigned)buf)) == 0 && (0x01 & len) == 0)
+		ioread16_rep(chip->IO_ADDR_R, buf, len >> 1);
+	else
+		ioread8_rep(chip->IO_ADDR_R, buf, len);
+}
+
+static void nand_davinci_write_buf(struct mtd_info *mtd,
+		const uint8_t *buf, int len)
+{
+	struct nand_chip *chip = mtd->priv;
+
+	if ((0x03 & ((unsigned)buf)) == 0 && (0x03 & len) == 0)
+		iowrite32_rep(chip->IO_ADDR_R, buf, len >> 2);
+	else if ((0x01 & ((unsigned)buf)) == 0 && (0x01 & len) == 0)
+		iowrite16_rep(chip->IO_ADDR_R, buf, len >> 1);
+	else
+		iowrite8_rep(chip->IO_ADDR_R, buf, len);
+}
+
+/*
+ * Check hardware register for wait status. Returns 1 if device is ready,
+ * 0 if it is still busy.
+ */
+static int nand_davinci_dev_ready(struct mtd_info *mtd)
+{
+	struct davinci_nand_info *info = to_davinci_nand(mtd);
+
+	return davinci_nand_readl(info, NANDFSR_OFFSET) & BIT(0);
+}
+
+static void __init nand_dm6446evm_flash_init(struct davinci_nand_info *info)
+{
+	uint32_t regval, a1cr;
+
+	/*
+	 * NAND FLASH timings @ PLL1 == 459 MHz
+	 *  - AEMIF.CLK freq   = PLL1/6 = 459/6 = 76.5 MHz
+	 *  - AEMIF.CLK period = 1/76.5 MHz = 13.1 ns
+	 */
+	regval = 0
+		| (0 << 31)           /* selectStrobe */
+		| (0 << 30)           /* extWait (never with NAND) */
+		| (1 << 26)           /* writeSetup      10 ns */
+		| (3 << 20)           /* writeStrobe     40 ns */
+		| (1 << 17)           /* writeHold       10 ns */
+		| (0 << 13)           /* readSetup       10 ns */
+		| (3 << 7)            /* readStrobe      60 ns */
+		| (0 << 4)            /* readHold        10 ns */
+		| (3 << 2)            /* turnAround      ?? ns */
+		| (0 << 0)            /* asyncSize       8-bit bus */
+		;
+	a1cr = davinci_nand_readl(info, A1CR_OFFSET);
+	if (a1cr != regval) {
+		dev_dbg(info->dev, "Warning: NAND config: Set A1CR " \
+		       "reg to 0x%08x, was 0x%08x, should be done by " \
+		       "bootloader.\n", regval, a1cr);
+		davinci_nand_writel(info, A1CR_OFFSET, regval);
+	}
+}
+
+/*----------------------------------------------------------------------*/
+
+static int __init nand_davinci_probe(struct platform_device *pdev)
+{
+	struct davinci_nand_pdata	*pdata = pdev->dev.platform_data;
+	struct davinci_nand_info	*info;
+	struct resource			*res1;
+	struct resource			*res2;
+	void __iomem			*vaddr;
+	void __iomem			*base;
+	int				ret;
+	uint32_t			val;
+	nand_ecc_modes_t		ecc_mode;
+
+	/* which external chipselect will we be managing? */
+	if (pdev->id < 0 || pdev->id > 3)
+		return -ENODEV;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info) {
+		dev_err(&pdev->dev, "unable to allocate memory\n");
+		ret = -ENOMEM;
+		goto err_nomem;
+	}
+
+	platform_set_drvdata(pdev, info);
+
+	res1 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	res2 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!res1 || !res2) {
+		dev_err(&pdev->dev, "resource missing\n");
+		ret = -EINVAL;
+		goto err_nomem;
+	}
+
+	vaddr = ioremap(res1->start, res1->end - res1->start);
+	base = ioremap(res2->start, res2->end - res2->start);
+	if (!vaddr || !base) {
+		dev_err(&pdev->dev, "ioremap failed\n");
+		ret = -EINVAL;
+		goto err_ioremap;
+	}
+
+	info->dev		= &pdev->dev;
+	info->base		= base;
+	info->vaddr		= vaddr;
+
+	info->mtd.priv		= &info->chip;
+	info->mtd.name		= dev_name(&pdev->dev);
+	info->mtd.owner		= THIS_MODULE;
+
+	info->chip.IO_ADDR_R	= vaddr;
+	info->chip.IO_ADDR_W	= vaddr;
+	info->chip.chip_delay	= 0;
+	info->chip.select_chip	= nand_davinci_select_chip;
+
+	/* options such as NAND_USE_FLASH_BBT or 16-bit widths */
+	info->chip.options	= pdata ? pdata->options : 0;
+
+	info->ioaddr		= (uint32_t __force) vaddr;
+
+	info->current_cs	= info->ioaddr;
+	info->core_chipsel	= pdev->id;
+	info->mask_chipsel	= pdata->mask_chipsel;
+
+	/* use nandboot-capable ALE/CLE masks by default */
+	if (pdata && pdata->mask_ale)
+		info->mask_ale	= pdata->mask_cle;
+	else
+		info->mask_ale	= MASK_ALE;
+	if (pdata && pdata->mask_cle)
+		info->mask_cle	= pdata->mask_cle;
+	else
+		info->mask_cle	= MASK_CLE;
+
+	/* Set address of hardware control function */
+	info->chip.cmd_ctrl	= nand_davinci_hwcontrol;
+	info->chip.dev_ready	= nand_davinci_dev_ready;
+
+	/* Speed up buffer I/O */
+	info->chip.read_buf     = nand_davinci_read_buf;
+	info->chip.write_buf    = nand_davinci_write_buf;
+
+	/* use board-specific ECC config; else, the best available */
+	if (pdata)
+		ecc_mode = pdata->ecc_mode;
+	else if (cpu_is_davinci_dm355())
+		ecc_mode = NAND_ECC_HW_SYNDROME;
+	else
+		ecc_mode = NAND_ECC_HW;
+
+	switch (ecc_mode) {
+	case NAND_ECC_NONE:
+	case NAND_ECC_SOFT:
+		break;
+	case NAND_ECC_HW:
+		info->chip.ecc.calculate = nand_davinci_calculate_1bit;
+		info->chip.ecc.correct = nand_davinci_correct_1bit;
+		info->chip.ecc.hwctl = nand_davinci_hwctl_1bit;
+		info->chip.ecc.size = 512;
+		info->chip.ecc.bytes = 3;
+		break;
+	case NAND_ECC_HW_SYNDROME:
+		/* FIXME implement */
+		info->chip.ecc.size = 512;
+		info->chip.ecc.bytes = 10;
+
+		dev_warn(&pdev->dev, "4-bit ECC nyet supported\n");
+		/* FALL THROUGH */
+	default:
+		ret = -EINVAL;
+		goto err_ecc;
+	}
+	info->chip.ecc.mode = ecc_mode;
+
+	info->clk = clk_get(&pdev->dev, "AEMIFCLK");
+	if (IS_ERR(info->clk)) {
+		ret = PTR_ERR(info->clk);
+		dev_dbg(&pdev->dev, "unable to get AEMIFCLK, err %d\n", ret);
+		goto err_clk;
+	}
+
+	ret = clk_enable(info->clk);
+	if (ret < 0) {
+		dev_dbg(&pdev->dev, "unable to enable AEMIFCLK, err %d\n", ret);
+		goto err_clk_enable;
+	}
+
+	/* EMIF timings should normally be set by the boot loader,
+	 * especially after boot-from-NAND.  The *only* reason to
+	 * have this special casing for the DM6446 EVM is to work
+	 * with boot-from-NOR ... with CS0 manually re-jumpered
+	 * (after startup) so it addresses the NAND flash, not NOR.
+	 * Even for dev boards, that's unusually rude...
+	 */
+	if (machine_is_davinci_evm())
+		nand_dm6446evm_flash_init(info);
+
+	spin_lock_irq(&davinci_nand_lock);
+
+	/* put CSxNAND into NAND mode */
+	val = davinci_nand_readl(info, NANDFCR_OFFSET);
+	val |= BIT(info->core_chipsel);
+	davinci_nand_writel(info, NANDFCR_OFFSET, val);
+
+	spin_unlock_irq(&davinci_nand_lock);
+
+	/* Scan to find existence of the device(s) */
+	ret = nand_scan(&info->mtd, pdata->mask_chipsel ? 2 : 1);
+	if (ret < 0) {
+		dev_dbg(&pdev->dev, "no NAND chip(s) found\n");
+		goto err_scan;
+	}
+
+	if (mtd_has_partitions()) {
+		struct mtd_partition	*mtd_parts = NULL;
+		int			mtd_parts_nb = 0;
+
+		if (mtd_has_cmdlinepart()) {
+			static const char *probes[] __initconst =
+				{ "cmdlinepart", NULL };
+
+			const char		*master_name;
+
+			/* Set info->mtd.name = 0 temporarily */
+			master_name		= info->mtd.name;
+			info->mtd.name		= (char *)0;
+
+			/* info->mtd.name == 0, means: don't bother checking
+			   <mtd-id> */
+			mtd_parts_nb = parse_mtd_partitions(&info->mtd, probes,
+							    &mtd_parts, 0);
+
+			/* Restore info->mtd.name */
+			info->mtd.name = master_name;
+		}
+
+		if (mtd_parts_nb <= 0 && pdata) {
+			mtd_parts = pdata->parts;
+			mtd_parts_nb = pdata->nr_parts;
+		}
+
+		/* Register any partitions */
+		if (mtd_parts_nb > 0) {
+			ret = add_mtd_partitions(&info->mtd,
+					mtd_parts, mtd_parts_nb);
+			if (ret == 0)
+				info->partitioned = true;
+		}
+
+	} else if (pdata && pdata->nr_parts) {
+		dev_warn(&pdev->dev, "ignoring %d default partitions on %s\n",
+				pdata->nr_parts, info->mtd.name);
+	}
+
+	/* If there's no partition info, just package the whole chip
+	 * as a single MTD device.
+	 */
+	if (!info->partitioned)
+		ret = add_mtd_device(&info->mtd) ? -ENODEV : 0;
+
+	if (ret < 0)
+		goto err_scan;
+
+	val = davinci_nand_readl(info, NRCSR_OFFSET);
+	dev_info(&pdev->dev, "controller rev. %d.%d\n",
+	       (val >> 8) & 0xff, val & 0xff);
+
+	return 0;
+
+err_scan:
+	clk_disable(info->clk);
+
+err_clk_enable:
+	clk_put(info->clk);
+
+err_ecc:
+err_clk:
+err_ioremap:
+	if (base)
+		iounmap(base);
+	if (vaddr)
+		iounmap(vaddr);
+
+err_nomem:
+	kfree(info);
+	return ret;
+}
+
+static int __exit nand_davinci_remove(struct platform_device *pdev)
+{
+	struct davinci_nand_info *info = platform_get_drvdata(pdev);
+	int status;
+
+	if (mtd_has_partitions() && info->partitioned)
+		status = del_mtd_partitions(&info->mtd);
+	else
+		status = del_mtd_device(&info->mtd);
+
+	iounmap(info->base);
+	iounmap(info->vaddr);
+
+	nand_release(&info->mtd);
+
+	clk_disable(info->clk);
+	clk_put(info->clk);
+
+	kfree(info);
+
+	return 0;
+}
+
+static struct platform_driver nand_davinci_driver = {
+	.remove		= __exit_p(nand_davinci_remove),
+	.driver		= {
+		.name	= "davinci_nand",
+	},
+};
+MODULE_ALIAS("platform:davinci_nand");
+
+static int __init nand_davinci_init(void)
+{
+	return platform_driver_probe(&nand_davinci_driver, nand_davinci_probe);
+}
+module_init(nand_davinci_init);
+
+static void __exit nand_davinci_exit(void)
+{
+	platform_driver_unregister(&nand_davinci_driver);
+}
+module_exit(nand_davinci_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Texas Instruments");
+MODULE_DESCRIPTION("Davinci NAND flash driver");
+