nand/mpc512x: Add MPC512x NAND support (NFC)

This patch adds NAND Flash Controller driver for MPC5121 revision 2.
All device features, except hardware ECC and power management, are
supported.

This NFC driver replaces the one orignally posted by John Rigby:

"[PATCH] Freescale NFC NAND driver"

It's a port of the Linux driver version posted by Piotr Ziecik a few
weeks ago. Using this driver has the following advantages (from my
point of view):

- Compatibility with the Linux NAND driver (e.g. ECC usage)
- Better code quality in general
- Resulting U-Boot image is a bit smaller (approx. 3k)
- Better to sync with newer Linux driver versions

The only disadvantage I can see, is that HW-ECC is not supported right
now. But this could be added later (e.g. port from Linux driver after
it's supported there). Using HW-ECC on the MCP5121 NFC has a general
problem because of the ECC usage in the spare area. This collides with
JFFS2 for example.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Piotr Ziecik <kosmo@semihalf.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: John Rigby <jcrigby@gmail.com>
Cc: Scott Wood <scottwood@freescale.com>

drivers/mtd/nand/Makefile

@@ -40,6 +40,7 @@ COBJS-$(CONFIG_DRIVER_NAND_BFIN) += bfin_nand.o
 COBJS-$(CONFIG_NAND_DAVINCI) += davinci_nand.o
 COBJS-$(CONFIG_NAND_FSL_ELBC) += fsl_elbc_nand.o
 COBJS-$(CONFIG_NAND_FSL_UPM) += fsl_upm.o
+COBJS-$(CONFIG_NAND_MPC5121_NFC) += mpc5121_nfc.o
 COBJS-$(CONFIG_NAND_NOMADIK) += nomadik.o
 COBJS-$(CONFIG_NAND_S3C2410) += s3c2410_nand.c
 COBJS-$(CONFIG_NAND_S3C64XX) += s3c64xx.o

drivers/mtd/nand/mpc5121_nfc.c

@@ -0,0 +1,692 @@
+/*
+ * Copyright 2004-2008 Freescale Semiconductor, Inc.
+ * Copyright 2009 Semihalf.
+ * (C) Copyright 2009 Stefan Roese <sr@denx.de>
+ *
+ * Based on original driver from Freescale Semiconductor
+ * written by John Rigby <jrigby@freescale.com> on basis
+ * of drivers/mtd/nand/mxc_nand.c. Reworked and extended
+ * Piotr Ziecik <kosmo@semihalf.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., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#include <common.h>
+#include <malloc.h>
+
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/nand_ecc.h>
+#include <linux/mtd/compat.h>
+
+#include <asm/errno.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <nand.h>
+
+#define DRV_NAME		"mpc5121_nfc"
+
+/* Timeouts */
+#define NFC_RESET_TIMEOUT	1000	/* 1 ms */
+#define NFC_TIMEOUT		2000	/* 2000 us */
+
+/* Addresses for NFC MAIN RAM BUFFER areas */
+#define NFC_MAIN_AREA(n)	((n) *  0x200)
+
+/* Addresses for NFC SPARE BUFFER areas */
+#define NFC_SPARE_BUFFERS	8
+#define NFC_SPARE_LEN		0x40
+#define NFC_SPARE_AREA(n)	(0x1000 + ((n) * NFC_SPARE_LEN))
+
+/* MPC5121 NFC registers */
+#define NFC_BUF_ADDR		0x1E04
+#define NFC_FLASH_ADDR		0x1E06
+#define NFC_FLASH_CMD		0x1E08
+#define NFC_CONFIG		0x1E0A
+#define NFC_ECC_STATUS1		0x1E0C
+#define NFC_ECC_STATUS2		0x1E0E
+#define NFC_SPAS		0x1E10
+#define NFC_WRPROT		0x1E12
+#define NFC_NF_WRPRST		0x1E18
+#define NFC_CONFIG1		0x1E1A
+#define NFC_CONFIG2		0x1E1C
+#define NFC_UNLOCKSTART_BLK0	0x1E20
+#define NFC_UNLOCKEND_BLK0	0x1E22
+#define NFC_UNLOCKSTART_BLK1	0x1E24
+#define NFC_UNLOCKEND_BLK1	0x1E26
+#define NFC_UNLOCKSTART_BLK2	0x1E28
+#define NFC_UNLOCKEND_BLK2	0x1E2A
+#define NFC_UNLOCKSTART_BLK3	0x1E2C
+#define NFC_UNLOCKEND_BLK3	0x1E2E
+
+/* Bit Definitions: NFC_BUF_ADDR */
+#define NFC_RBA_MASK		(7 << 0)
+#define NFC_ACTIVE_CS_SHIFT	5
+#define NFC_ACTIVE_CS_MASK	(3 << NFC_ACTIVE_CS_SHIFT)
+
+/* Bit Definitions: NFC_CONFIG */
+#define NFC_BLS_UNLOCKED	(1 << 1)
+
+/* Bit Definitions: NFC_CONFIG1 */
+#define NFC_ECC_4BIT		(1 << 0)
+#define NFC_FULL_PAGE_DMA	(1 << 1)
+#define NFC_SPARE_ONLY		(1 << 2)
+#define NFC_ECC_ENABLE		(1 << 3)
+#define NFC_INT_MASK		(1 << 4)
+#define NFC_BIG_ENDIAN		(1 << 5)
+#define NFC_RESET		(1 << 6)
+#define NFC_CE			(1 << 7)
+#define NFC_ONE_CYCLE		(1 << 8)
+#define NFC_PPB_32		(0 << 9)
+#define NFC_PPB_64		(1 << 9)
+#define NFC_PPB_128		(2 << 9)
+#define NFC_PPB_256		(3 << 9)
+#define NFC_PPB_MASK		(3 << 9)
+#define NFC_FULL_PAGE_INT	(1 << 11)
+
+/* Bit Definitions: NFC_CONFIG2 */
+#define NFC_COMMAND		(1 << 0)
+#define NFC_ADDRESS		(1 << 1)
+#define NFC_INPUT		(1 << 2)
+#define NFC_OUTPUT		(1 << 3)
+#define NFC_ID			(1 << 4)
+#define NFC_STATUS		(1 << 5)
+#define NFC_CMD_FAIL		(1 << 15)
+#define NFC_INT			(1 << 15)
+
+/* Bit Definitions: NFC_WRPROT */
+#define NFC_WPC_LOCK_TIGHT	(1 << 0)
+#define NFC_WPC_LOCK		(1 << 1)
+#define NFC_WPC_UNLOCK		(1 << 2)
+
+struct mpc5121_nfc_prv {
+	struct mtd_info mtd;
+	struct nand_chip chip;
+	int irq;
+	void __iomem *regs;
+	struct clk *clk;
+	uint column;
+	int spareonly;
+	int chipsel;
+};
+
+int mpc5121_nfc_chip = 0;
+
+static void mpc5121_nfc_done(struct mtd_info *mtd);
+
+/* Read NFC register */
+static inline u16 nfc_read(struct mtd_info *mtd, uint reg)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+
+	return in_be16(prv->regs + reg);
+}
+
+/* Write NFC register */
+static inline void nfc_write(struct mtd_info *mtd, uint reg, u16 val)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+
+	out_be16(prv->regs + reg, val);
+}
+
+/* Set bits in NFC register */
+static inline void nfc_set(struct mtd_info *mtd, uint reg, u16 bits)
+{
+	nfc_write(mtd, reg, nfc_read(mtd, reg) | bits);
+}
+
+/* Clear bits in NFC register */
+static inline void nfc_clear(struct mtd_info *mtd, uint reg, u16 bits)
+{
+	nfc_write(mtd, reg, nfc_read(mtd, reg) & ~bits);
+}
+
+/* Invoke address cycle */
+static inline void mpc5121_nfc_send_addr(struct mtd_info *mtd, u16 addr)
+{
+	nfc_write(mtd, NFC_FLASH_ADDR, addr);
+	nfc_write(mtd, NFC_CONFIG2, NFC_ADDRESS);
+	mpc5121_nfc_done(mtd);
+}
+
+/* Invoke command cycle */
+static inline void mpc5121_nfc_send_cmd(struct mtd_info *mtd, u16 cmd)
+{
+	nfc_write(mtd, NFC_FLASH_CMD, cmd);
+	nfc_write(mtd, NFC_CONFIG2, NFC_COMMAND);
+	mpc5121_nfc_done(mtd);
+}
+
+/* Send data from NFC buffers to NAND flash */
+static inline void mpc5121_nfc_send_prog_page(struct mtd_info *mtd)
+{
+	nfc_clear(mtd, NFC_BUF_ADDR, NFC_RBA_MASK);
+	nfc_write(mtd, NFC_CONFIG2, NFC_INPUT);
+	mpc5121_nfc_done(mtd);
+}
+
+/* Receive data from NAND flash */
+static inline void mpc5121_nfc_send_read_page(struct mtd_info *mtd)
+{
+	nfc_clear(mtd, NFC_BUF_ADDR, NFC_RBA_MASK);
+	nfc_write(mtd, NFC_CONFIG2, NFC_OUTPUT);
+	mpc5121_nfc_done(mtd);
+}
+
+/* Receive ID from NAND flash */
+static inline void mpc5121_nfc_send_read_id(struct mtd_info *mtd)
+{
+	nfc_clear(mtd, NFC_BUF_ADDR, NFC_RBA_MASK);
+	nfc_write(mtd, NFC_CONFIG2, NFC_ID);
+	mpc5121_nfc_done(mtd);
+}
+
+/* Receive status from NAND flash */
+static inline void mpc5121_nfc_send_read_status(struct mtd_info *mtd)
+{
+	nfc_clear(mtd, NFC_BUF_ADDR, NFC_RBA_MASK);
+	nfc_write(mtd, NFC_CONFIG2, NFC_STATUS);
+	mpc5121_nfc_done(mtd);
+}
+
+static void mpc5121_nfc_done(struct mtd_info *mtd)
+{
+	int max_retries = NFC_TIMEOUT;
+
+	while (1) {
+		max_retries--;
+		if (nfc_read(mtd, NFC_CONFIG2) & NFC_INT)
+			break;
+		udelay(1);
+	}
+
+	if (max_retries <= 0)
+		printk(KERN_WARNING DRV_NAME
+		       ": Timeout while waiting for completion.\n");
+}
+
+/* Do address cycle(s) */
+static void mpc5121_nfc_addr_cycle(struct mtd_info *mtd, int column, int page)
+{
+	struct nand_chip *chip = mtd->priv;
+	u32 pagemask = chip->pagemask;
+
+	if (column != -1) {
+		mpc5121_nfc_send_addr(mtd, column);
+		if (mtd->writesize > 512)
+			mpc5121_nfc_send_addr(mtd, column >> 8);
+	}
+
+	if (page != -1) {
+		do {
+			mpc5121_nfc_send_addr(mtd, page & 0xFF);
+			page >>= 8;
+			pagemask >>= 8;
+		} while (pagemask);
+	}
+}
+
+/* Control chip select signals */
+
+/*
+ * Selecting the active device:
+ *
+ * This is different than the linux version. Switching between chips
+ * is done via board_nand_select_device(). The Linux select_chip
+ * function used here in U-Boot has only 2 valid chip numbers:
+ * 	0 select
+ * 	-1 deselect
+ */
+
+/*
+ * Implement it as a weak default, so that boards with a specific
+ * chip-select routine can use their own function.
+ */
+void __mpc5121_nfc_select_chip(struct mtd_info *mtd, int chip)
+{
+	if (chip < 0) {
+		nfc_clear(mtd, NFC_CONFIG1, NFC_CE);
+		return;
+	}
+
+	nfc_clear(mtd, NFC_BUF_ADDR, NFC_ACTIVE_CS_MASK);
+	nfc_set(mtd, NFC_BUF_ADDR, (chip << NFC_ACTIVE_CS_SHIFT) &
+		NFC_ACTIVE_CS_MASK);
+	nfc_set(mtd, NFC_CONFIG1, NFC_CE);
+}
+void mpc5121_nfc_select_chip(struct mtd_info *mtd, int chip)
+	__attribute__((weak, alias("__mpc5121_nfc_select_chip")));
+
+void board_nand_select_device(struct nand_chip *nand, int chip)
+{
+	/*
+	 * Only save this chip number in global variable here. This
+	 * will be used later in mpc5121_nfc_select_chip().
+	 */
+	mpc5121_nfc_chip = chip;
+}
+
+/* Read NAND Ready/Busy signal */
+static int mpc5121_nfc_dev_ready(struct mtd_info *mtd)
+{
+	/*
+	 * NFC handles ready/busy signal internally. Therefore, this function
+	 * always returns status as ready.
+	 */
+	return 1;
+}
+
+/* Write command to NAND flash */
+static void mpc5121_nfc_command(struct mtd_info *mtd, unsigned command,
+				int column, int page)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+
+	prv->column = (column >= 0) ? column : 0;
+	prv->spareonly = 0;
+
+	switch (command) {
+	case NAND_CMD_PAGEPROG:
+		mpc5121_nfc_send_prog_page(mtd);
+		break;
+		/*
+		 * NFC does not support sub-page reads and writes,
+		 * so emulate them using full page transfers.
+		 */
+	case NAND_CMD_READ0:
+		column = 0;
+		break;
+
+	case NAND_CMD_READ1:
+		prv->column += 256;
+		command = NAND_CMD_READ0;
+		column = 0;
+		break;
+
+	case NAND_CMD_READOOB:
+		prv->spareonly = 1;
+		command = NAND_CMD_READ0;
+		column = 0;
+		break;
+
+	case NAND_CMD_SEQIN:
+		mpc5121_nfc_command(mtd, NAND_CMD_READ0, column, page);
+		column = 0;
+		break;
+
+	case NAND_CMD_ERASE1:
+	case NAND_CMD_ERASE2:
+	case NAND_CMD_READID:
+	case NAND_CMD_STATUS:
+		break;
+
+	default:
+		return;
+	}
+
+	mpc5121_nfc_send_cmd(mtd, command);
+	mpc5121_nfc_addr_cycle(mtd, column, page);
+
+	switch (command) {
+	case NAND_CMD_READ0:
+		if (mtd->writesize > 512)
+			mpc5121_nfc_send_cmd(mtd, NAND_CMD_READSTART);
+		mpc5121_nfc_send_read_page(mtd);
+		break;
+
+	case NAND_CMD_READID:
+		mpc5121_nfc_send_read_id(mtd);
+		break;
+
+	case NAND_CMD_STATUS:
+		mpc5121_nfc_send_read_status(mtd);
+		if (chip->options & NAND_BUSWIDTH_16)
+			prv->column = 1;
+		else
+			prv->column = 0;
+		break;
+	}
+}
+
+/* Copy data from/to NFC spare buffers. */
+static void mpc5121_nfc_copy_spare(struct mtd_info *mtd, uint offset,
+				   u8 * buffer, uint size, int wr)
+{
+	struct nand_chip *nand = mtd->priv;
+	struct mpc5121_nfc_prv *prv = nand->priv;
+	uint o, s, sbsize, blksize;
+
+	/*
+	 * NAND spare area is available through NFC spare buffers.
+	 * The NFC divides spare area into (page_size / 512) chunks.
+	 * Each chunk is placed into separate spare memory area, using
+	 * first (spare_size / num_of_chunks) bytes of the buffer.
+	 *
+	 * For NAND device in which the spare area is not divided fully
+	 * by the number of chunks, number of used bytes in each spare
+	 * buffer is rounded down to the nearest even number of bytes,
+	 * and all remaining bytes are added to the last used spare area.
+	 *
+	 * For more information read section 26.6.10 of MPC5121e
+	 * Microcontroller Reference Manual, Rev. 3.
+	 */
+
+	/* Calculate number of valid bytes in each spare buffer */
+	sbsize = (mtd->oobsize / (mtd->writesize / 512)) & ~1;
+
+	while (size) {
+		/* Calculate spare buffer number */
+		s = offset / sbsize;
+		if (s > NFC_SPARE_BUFFERS - 1)
+			s = NFC_SPARE_BUFFERS - 1;
+
+		/*
+		 * Calculate offset to requested data block in selected spare
+		 * buffer and its size.
+		 */
+		o = offset - (s * sbsize);
+		blksize = min(sbsize - o, size);
+
+		if (wr)
+			memcpy_toio(prv->regs + NFC_SPARE_AREA(s) + o,
+				    buffer, blksize);
+		else
+			memcpy_fromio(buffer,
+				      prv->regs + NFC_SPARE_AREA(s) + o,
+				      blksize);
+
+		buffer += blksize;
+		offset += blksize;
+		size -= blksize;
+	};
+}
+
+/* Copy data from/to NFC main and spare buffers */
+static void mpc5121_nfc_buf_copy(struct mtd_info *mtd, u_char * buf, int len,
+				 int wr)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct mpc5121_nfc_prv *prv = chip->priv;
+	uint c = prv->column;
+	uint l;
+
+	/* Handle spare area access */
+	if (prv->spareonly || c >= mtd->writesize) {
+		/* Calculate offset from beginning of spare area */
+		if (c >= mtd->writesize)
+			c -= mtd->writesize;
+
+		prv->column += len;
+		mpc5121_nfc_copy_spare(mtd, c, buf, len, wr);
+		return;
+	}
+
+	/*
+	 * Handle main area access - limit copy length to prevent
+	 * crossing main/spare boundary.
+	 */
+	l = min((uint) len, mtd->writesize - c);
+	prv->column += l;
+
+	if (wr)
+		memcpy_toio(prv->regs + NFC_MAIN_AREA(0) + c, buf, l);
+	else
+		memcpy_fromio(buf, prv->regs + NFC_MAIN_AREA(0) + c, l);
+
+	/* Handle crossing main/spare boundary */
+	if (l != len) {
+		buf += l;
+		len -= l;
+		mpc5121_nfc_buf_copy(mtd, buf, len, wr);
+	}
+}
+
+/* Read data from NFC buffers */
+static void mpc5121_nfc_read_buf(struct mtd_info *mtd, u_char * buf, int len)
+{
+	mpc5121_nfc_buf_copy(mtd, buf, len, 0);
+}
+
+/* Write data to NFC buffers */
+static void mpc5121_nfc_write_buf(struct mtd_info *mtd,
+				  const u_char * buf, int len)
+{
+	mpc5121_nfc_buf_copy(mtd, (u_char *) buf, len, 1);
+}
+
+/* Compare buffer with NAND flash */
+static int mpc5121_nfc_verify_buf(struct mtd_info *mtd,
+				  const u_char * buf, int len)
+{
+	u_char tmp[256];
+	uint bsize;
+
+	while (len) {
+		bsize = min(len, 256);
+		mpc5121_nfc_read_buf(mtd, tmp, bsize);
+
+		if (memcmp(buf, tmp, bsize))
+			return 1;
+
+		buf += bsize;
+		len -= bsize;
+	}
+
+	return 0;
+}
+
+/* Read byte from NFC buffers */
+static u8 mpc5121_nfc_read_byte(struct mtd_info *mtd)
+{
+	u8 tmp;
+
+	mpc5121_nfc_read_buf(mtd, &tmp, sizeof(tmp));
+
+	return tmp;
+}
+
+/* Read word from NFC buffers */
+static u16 mpc5121_nfc_read_word(struct mtd_info *mtd)
+{
+	u16 tmp;
+
+	mpc5121_nfc_read_buf(mtd, (u_char *) & tmp, sizeof(tmp));
+
+	return tmp;
+}
+
+/*
+ * Read NFC configuration from Reset Config Word
+ *
+ * NFC is configured during reset in basis of information stored
+ * in Reset Config Word. There is no other way to set NAND block
+ * size, spare size and bus width.
+ */
+static int mpc5121_nfc_read_hw_config(struct mtd_info *mtd)
+{
+	immap_t *im = (immap_t *)CONFIG_SYS_IMMR;
+	struct nand_chip *chip = mtd->priv;
+	uint rcw_pagesize = 0;
+	uint rcw_sparesize = 0;
+	uint rcw_width;
+	uint rcwh;
+	uint romloc, ps;
+
+	rcwh = in_be32(&(im->reset.rcwh));
+
+	/* Bit 6: NFC bus width */
+	rcw_width = ((rcwh >> 6) & 0x1) ? 2 : 1;
+
+	/* Bit 7: NFC Page/Spare size */
+	ps = (rcwh >> 7) & 0x1;
+
+	/* Bits [22:21]: ROM Location */
+	romloc = (rcwh >> 21) & 0x3;
+
+	/* Decode RCW bits */
+	switch ((ps << 2) | romloc) {
+	case 0x00:
+	case 0x01:
+		rcw_pagesize = 512;
+		rcw_sparesize = 16;
+		break;
+	case 0x02:
+	case 0x03:
+		rcw_pagesize = 4096;
+		rcw_sparesize = 128;
+		break;
+	case 0x04:
+	case 0x05:
+		rcw_pagesize = 2048;
+		rcw_sparesize = 64;
+		break;
+	case 0x06:
+	case 0x07:
+		rcw_pagesize = 4096;
+		rcw_sparesize = 218;
+		break;
+	}
+
+	mtd->writesize = rcw_pagesize;
+	mtd->oobsize = rcw_sparesize;
+	if (rcw_width == 2)
+		chip->options |= NAND_BUSWIDTH_16;
+
+	debug(KERN_NOTICE DRV_NAME ": Configured for "
+	      "%u-bit NAND, page size %u with %u spare.\n",
+	      rcw_width * 8, rcw_pagesize, rcw_sparesize);
+	return 0;
+}
+
+int board_nand_init(struct nand_chip *chip)
+{
+	struct mpc5121_nfc_prv *prv;
+	struct mtd_info *mtd;
+	int resettime = 0;
+	int retval = 0;
+	int rev;
+	static int chip_nr = 0;
+
+	/*
+	 * Check SoC revision. This driver supports only NFC
+	 * in MPC5121 revision 2.
+	 */
+	rev = (mfspr(SPRN_SVR) >> 4) & 0xF;
+	if (rev != 2) {
+		printk(KERN_ERR DRV_NAME
+		       ": SoC revision %u is not supported!\n", rev);
+		return -ENXIO;
+	}
+
+	prv = malloc(sizeof(*prv));
+	if (!prv) {
+		printk(KERN_ERR DRV_NAME ": Memory exhausted!\n");
+		return -ENOMEM;
+	}
+
+	mtd = &nand_info[chip_nr++];
+	mtd->priv = chip;
+	chip->priv = prv;
+
+	/* Read NFC configuration from Reset Config Word */
+	retval = mpc5121_nfc_read_hw_config(mtd);
+	if (retval) {
+		printk(KERN_ERR DRV_NAME ": Unable to read NFC config!\n");
+		return retval;
+	}
+
+	prv->regs = (void __iomem *)CONFIG_SYS_NAND_BASE;
+	chip->dev_ready = mpc5121_nfc_dev_ready;
+	chip->cmdfunc = mpc5121_nfc_command;
+	chip->read_byte = mpc5121_nfc_read_byte;
+	chip->read_word = mpc5121_nfc_read_word;
+	chip->read_buf = mpc5121_nfc_read_buf;
+	chip->write_buf = mpc5121_nfc_write_buf;
+	chip->verify_buf = mpc5121_nfc_verify_buf;
+	chip->select_chip = mpc5121_nfc_select_chip;
+	chip->options = NAND_NO_AUTOINCR | NAND_USE_FLASH_BBT;
+	chip->ecc.mode = NAND_ECC_SOFT;
+
+	/* Reset NAND Flash controller */
+	nfc_set(mtd, NFC_CONFIG1, NFC_RESET);
+	while (nfc_read(mtd, NFC_CONFIG1) & NFC_RESET) {
+		if (resettime++ >= NFC_RESET_TIMEOUT) {
+			printk(KERN_ERR DRV_NAME
+			       ": Timeout while resetting NFC!\n");
+			retval = -EINVAL;
+			goto error;
+		}
+
+		udelay(1);
+	}
+
+	/* Enable write to NFC memory */
+	nfc_write(mtd, NFC_CONFIG, NFC_BLS_UNLOCKED);
+
+	/* Enable write to all NAND pages */
+	nfc_write(mtd, NFC_UNLOCKSTART_BLK0, 0x0000);
+	nfc_write(mtd, NFC_UNLOCKEND_BLK0, 0xFFFF);
+	nfc_write(mtd, NFC_WRPROT, NFC_WPC_UNLOCK);
+
+	/*
+	 * Setup NFC:
+	 *      - Big Endian transfers,
+	 *      - Interrupt after full page read/write.
+	 */
+	nfc_write(mtd, NFC_CONFIG1, NFC_BIG_ENDIAN | NFC_INT_MASK |
+		  NFC_FULL_PAGE_INT);
+
+	/* Set spare area size */
+	nfc_write(mtd, NFC_SPAS, mtd->oobsize >> 1);
+
+	/* Detect NAND chips */
+	if (nand_scan(mtd, 1)) {
+		printk(KERN_ERR DRV_NAME ": NAND Flash not found !\n");
+		retval = -ENXIO;
+		goto error;
+	}
+
+	/* Set erase block size */
+	switch (mtd->erasesize / mtd->writesize) {
+	case 32:
+		nfc_set(mtd, NFC_CONFIG1, NFC_PPB_32);
+		break;
+
+	case 64:
+		nfc_set(mtd, NFC_CONFIG1, NFC_PPB_64);
+		break;
+
+	case 128:
+		nfc_set(mtd, NFC_CONFIG1, NFC_PPB_128);
+		break;
+
+	case 256:
+		nfc_set(mtd, NFC_CONFIG1, NFC_PPB_256);
+		break;
+
+	default:
+		printk(KERN_ERR DRV_NAME ": Unsupported NAND flash!\n");
+		retval = -ENXIO;
+		goto error;
+	}
+
+	return 0;
+error:
+	return retval;
+}