tegra: nand: Add Tegra NAND driver

A device tree is used to configure the NAND, including memory
timings and block/pages sizes.

If this node is not present or is disabled, then NAND will not
be initialized.

Signed-off-by: Jim Lin <jilin@nvidia.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/drivers/mtd/nand/tegra_nand.c b/drivers/mtd/nand/tegra_nand.c
new file mode 100644
index 0000000..8c1de34
--- /dev/null
+++ b/drivers/mtd/nand/tegra_nand.c
@@ -0,0 +1,1026 @@
+/*
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * (C) Copyright 2011 NVIDIA Corporation <www.nvidia.com>
+ * (C) Copyright 2006 Detlev Zundel, dzu@denx.de
+ * (C) Copyright 2006 DENX Software Engineering
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <nand.h>
+#include <asm/arch/clk_rst.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/funcmux.h>
+#include <asm/arch/gpio.h>
+#include <asm/errno.h>
+#include <asm-generic/gpio.h>
+#include <fdtdec.h>
+#include "tegra_nand.h"
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define NAND_CMD_TIMEOUT_MS		10
+
+#define SKIPPED_SPARE_BYTES		4
+
+/* ECC bytes to be generated for tag data */
+#define TAG_ECC_BYTES			4
+
+/* 64 byte oob block info for large page (== 2KB) device
+ *
+ * OOB flash layout for Tegra with Reed-Solomon 4 symbol correct ECC:
+ *      Skipped bytes(4)
+ *      Main area Ecc(36)
+ *      Tag data(20)
+ *      Tag data Ecc(4)
+ *
+ * Yaffs2 will use 16 tag bytes.
+ */
+static struct nand_ecclayout eccoob = {
+	.eccbytes = 36,
+	.eccpos = {
+		4,  5,  6,  7,  8,  9,  10, 11, 12,
+		13, 14, 15, 16, 17, 18, 19, 20, 21,
+		22, 23, 24, 25, 26, 27, 28, 29, 30,
+		31, 32, 33, 34, 35, 36, 37, 38, 39,
+	},
+	.oobavail = 20,
+	.oobfree = {
+			{
+			.offset = 40,
+			.length = 20,
+			},
+	}
+};
+
+enum {
+	ECC_OK,
+	ECC_TAG_ERROR = 1 << 0,
+	ECC_DATA_ERROR = 1 << 1
+};
+
+/* Timing parameters */
+enum {
+	FDT_NAND_MAX_TRP_TREA,
+	FDT_NAND_TWB,
+	FDT_NAND_MAX_TCR_TAR_TRR,
+	FDT_NAND_TWHR,
+	FDT_NAND_MAX_TCS_TCH_TALS_TALH,
+	FDT_NAND_TWH,
+	FDT_NAND_TWP,
+	FDT_NAND_TRH,
+	FDT_NAND_TADL,
+
+	FDT_NAND_TIMING_COUNT
+};
+
+/* Information about an attached NAND chip */
+struct fdt_nand {
+	struct nand_ctlr *reg;
+	int enabled;		/* 1 to enable, 0 to disable */
+	struct fdt_gpio_state wp_gpio;	/* write-protect GPIO */
+	s32 width;		/* bit width, normally 8 */
+	u32 timing[FDT_NAND_TIMING_COUNT];
+};
+
+struct nand_drv {
+	struct nand_ctlr *reg;
+
+	/*
+	* When running in PIO mode to get READ ID bytes from register
+	* RESP_0, we need this variable as an index to know which byte in
+	* register RESP_0 should be read.
+	* Because common code in nand_base.c invokes read_byte function two
+	* times for NAND_CMD_READID.
+	* And our controller returns 4 bytes at once in register RESP_0.
+	*/
+	int pio_byte_index;
+	struct fdt_nand config;
+};
+
+static struct nand_drv nand_ctrl;
+static struct mtd_info *our_mtd;
+static struct nand_chip nand_chip[CONFIG_SYS_MAX_NAND_DEVICE];
+
+#ifdef CONFIG_SYS_DCACHE_OFF
+static inline void dma_prepare(void *start, unsigned long length,
+			       int is_writing)
+{
+}
+#else
+/**
+ * Prepare for a DMA transaction
+ *
+ * For a write we flush out our data. For a read we invalidate, since we
+ * need to do this before we read from the buffer after the DMA has
+ * completed, so may as well do it now.
+ *
+ * @param start		Start address for DMA buffer (should be cache-aligned)
+ * @param length	Length of DMA buffer in bytes
+ * @param is_writing	0 if reading, non-zero if writing
+ */
+static void dma_prepare(void *start, unsigned long length, int is_writing)
+{
+	unsigned long addr = (unsigned long)start;
+
+	length = ALIGN(length, ARCH_DMA_MINALIGN);
+	if (is_writing)
+		flush_dcache_range(addr, addr + length);
+	else
+		invalidate_dcache_range(addr, addr + length);
+}
+#endif
+
+/**
+ * Wait for command completion
+ *
+ * @param reg	nand_ctlr structure
+ * @return
+ *	1 - Command completed
+ *	0 - Timeout
+ */
+static int nand_waitfor_cmd_completion(struct nand_ctlr *reg)
+{
+	u32 reg_val;
+	int running;
+	int i;
+
+	for (i = 0; i < NAND_CMD_TIMEOUT_MS * 1000; i++) {
+		if ((readl(&reg->command) & CMD_GO) ||
+				!(readl(&reg->status) & STATUS_RBSY0) ||
+				!(readl(&reg->isr) & ISR_IS_CMD_DONE)) {
+			udelay(1);
+			continue;
+		}
+		reg_val = readl(&reg->dma_mst_ctrl);
+		/*
+		 * If DMA_MST_CTRL_EN_A_ENABLE or DMA_MST_CTRL_EN_B_ENABLE
+		 * is set, that means DMA engine is running.
+		 *
+		 * Then we have to wait until DMA_MST_CTRL_IS_DMA_DONE
+		 * is cleared, indicating DMA transfer completion.
+		 */
+		running = reg_val & (DMA_MST_CTRL_EN_A_ENABLE |
+				DMA_MST_CTRL_EN_B_ENABLE);
+		if (!running || (reg_val & DMA_MST_CTRL_IS_DMA_DONE))
+			return 1;
+		udelay(1);
+	}
+	return 0;
+}
+
+/**
+ * Read one byte from the chip
+ *
+ * @param mtd	MTD device structure
+ * @return	data byte
+ *
+ * Read function for 8bit bus-width
+ */
+static uint8_t read_byte(struct mtd_info *mtd)
+{
+	struct nand_chip *chip = mtd->priv;
+	u32 dword_read;
+	struct nand_drv *info;
+
+	info = (struct nand_drv *)chip->priv;
+
+	/* In PIO mode, only 4 bytes can be transferred with single CMD_GO. */
+	if (info->pio_byte_index > 3) {
+		info->pio_byte_index = 0;
+		writel(CMD_GO | CMD_PIO
+			| CMD_RX | CMD_CE0,
+			&info->reg->command);
+		if (!nand_waitfor_cmd_completion(info->reg))
+			printf("Command timeout\n");
+	}
+
+	dword_read = readl(&info->reg->resp);
+	dword_read = dword_read >> (8 * info->pio_byte_index);
+	info->pio_byte_index++;
+	return (uint8_t)dword_read;
+}
+
+/**
+ * Check NAND status to see if it is ready or not
+ *
+ * @param mtd	MTD device structure
+ * @return
+ *	1 - ready
+ *	0 - not ready
+ */
+static int nand_dev_ready(struct mtd_info *mtd)
+{
+	struct nand_chip *chip = mtd->priv;
+	int reg_val;
+	struct nand_drv *info;
+
+	info = (struct nand_drv *)chip->priv;
+
+	reg_val = readl(&info->reg->status);
+	if (reg_val & STATUS_RBSY0)
+		return 1;
+	else
+		return 0;
+}
+
+/* Dummy implementation: we don't support multiple chips */
+static void nand_select_chip(struct mtd_info *mtd, int chipnr)
+{
+	switch (chipnr) {
+	case -1:
+	case 0:
+		break;
+
+	default:
+		BUG();
+	}
+}
+
+/**
+ * Clear all interrupt status bits
+ *
+ * @param reg	nand_ctlr structure
+ */
+static void nand_clear_interrupt_status(struct nand_ctlr *reg)
+{
+	u32 reg_val;
+
+	/* Clear interrupt status */
+	reg_val = readl(&reg->isr);
+	writel(reg_val, &reg->isr);
+}
+
+/**
+ * Send command to NAND device
+ *
+ * @param mtd		MTD device structure
+ * @param command	the command to be sent
+ * @param column	the column address for this command, -1 if none
+ * @param page_addr	the page address for this command, -1 if none
+ */
+static void nand_command(struct mtd_info *mtd, unsigned int command,
+	int column, int page_addr)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct nand_drv *info;
+
+	info = (struct nand_drv *)chip->priv;
+
+	/*
+	 * Write out the command to the device.
+	 *
+	 * Only command NAND_CMD_RESET or NAND_CMD_READID will come
+	 * here before mtd->writesize is initialized.
+	 */
+
+	/* Emulate NAND_CMD_READOOB */
+	if (command == NAND_CMD_READOOB) {
+		assert(mtd->writesize != 0);
+		column += mtd->writesize;
+		command = NAND_CMD_READ0;
+	}
+
+	/* Adjust columns for 16 bit bus-width */
+	if (column != -1 && (chip->options & NAND_BUSWIDTH_16))
+		column >>= 1;
+
+	nand_clear_interrupt_status(info->reg);
+
+	/* Stop DMA engine, clear DMA completion status */
+	writel(DMA_MST_CTRL_EN_A_DISABLE
+		| DMA_MST_CTRL_EN_B_DISABLE
+		| DMA_MST_CTRL_IS_DMA_DONE,
+		&info->reg->dma_mst_ctrl);
+
+	/*
+	 * Program and erase have their own busy handlers
+	 * status and sequential in needs no delay
+	 */
+	switch (command) {
+	case NAND_CMD_READID:
+		writel(NAND_CMD_READID, &info->reg->cmd_reg1);
+		writel(CMD_GO | CMD_CLE | CMD_ALE | CMD_PIO
+			| CMD_RX |
+			((4 - 1) << CMD_TRANS_SIZE_SHIFT)
+			| CMD_CE0,
+			&info->reg->command);
+		info->pio_byte_index = 0;
+		break;
+	case NAND_CMD_READ0:
+		writel(NAND_CMD_READ0, &info->reg->cmd_reg1);
+		writel(NAND_CMD_READSTART, &info->reg->cmd_reg2);
+		writel((page_addr << 16) | (column & 0xFFFF),
+			&info->reg->addr_reg1);
+		writel(page_addr >> 16, &info->reg->addr_reg2);
+		return;
+	case NAND_CMD_SEQIN:
+		writel(NAND_CMD_SEQIN, &info->reg->cmd_reg1);
+		writel(NAND_CMD_PAGEPROG, &info->reg->cmd_reg2);
+		writel((page_addr << 16) | (column & 0xFFFF),
+			&info->reg->addr_reg1);
+		writel(page_addr >> 16,
+			&info->reg->addr_reg2);
+		return;
+	case NAND_CMD_PAGEPROG:
+		return;
+	case NAND_CMD_ERASE1:
+		writel(NAND_CMD_ERASE1, &info->reg->cmd_reg1);
+		writel(NAND_CMD_ERASE2, &info->reg->cmd_reg2);
+		writel(page_addr, &info->reg->addr_reg1);
+		writel(CMD_GO | CMD_CLE | CMD_ALE |
+			CMD_SEC_CMD | CMD_CE0 | CMD_ALE_BYTES3,
+			&info->reg->command);
+		break;
+	case NAND_CMD_ERASE2:
+		return;
+	case NAND_CMD_STATUS:
+		writel(NAND_CMD_STATUS, &info->reg->cmd_reg1);
+		writel(CMD_GO | CMD_CLE | CMD_PIO | CMD_RX
+			| ((1 - 0) << CMD_TRANS_SIZE_SHIFT)
+			| CMD_CE0,
+			&info->reg->command);
+		info->pio_byte_index = 0;
+		break;
+	case NAND_CMD_RESET:
+		writel(NAND_CMD_RESET, &info->reg->cmd_reg1);
+		writel(CMD_GO | CMD_CLE | CMD_CE0,
+			&info->reg->command);
+		break;
+	case NAND_CMD_RNDOUT:
+	default:
+		printf("%s: Unsupported command %d\n", __func__, command);
+		return;
+	}
+	if (!nand_waitfor_cmd_completion(info->reg))
+		printf("Command 0x%02X timeout\n", command);
+}
+
+/**
+ * Check whether the pointed buffer are all 0xff (blank).
+ *
+ * @param buf	data buffer for blank check
+ * @param len	length of the buffer in byte
+ * @return
+ *	1 - blank
+ *	0 - non-blank
+ */
+static int blank_check(u8 *buf, int len)
+{
+	int i;
+
+	for (i = 0; i < len; i++)
+		if (buf[i] != 0xFF)
+			return 0;
+	return 1;
+}
+
+/**
+ * After a DMA transfer for read, we call this function to see whether there
+ * is any uncorrectable error on the pointed data buffer or oob buffer.
+ *
+ * @param reg		nand_ctlr structure
+ * @param databuf	data buffer
+ * @param a_len		data buffer length
+ * @param oobbuf	oob buffer
+ * @param b_len		oob buffer length
+ * @return
+ *	ECC_OK - no ECC error or correctable ECC error
+ *	ECC_TAG_ERROR - uncorrectable tag ECC error
+ *	ECC_DATA_ERROR - uncorrectable data ECC error
+ *	ECC_DATA_ERROR + ECC_TAG_ERROR - uncorrectable data+tag ECC error
+ */
+static int check_ecc_error(struct nand_ctlr *reg, u8 *databuf,
+	int a_len, u8 *oobbuf, int b_len)
+{
+	int return_val = ECC_OK;
+	u32 reg_val;
+
+	if (!(readl(&reg->isr) & ISR_IS_ECC_ERR))
+		return ECC_OK;
+
+	/*
+	 * Area A is used for the data block (databuf). Area B is used for
+	 * the spare block (oobbuf)
+	 */
+	reg_val = readl(&reg->dec_status);
+	if ((reg_val & DEC_STATUS_A_ECC_FAIL) && databuf) {
+		reg_val = readl(&reg->bch_dec_status_buf);
+		/*
+		 * If uncorrectable error occurs on data area, then see whether
+		 * they are all FF. If all are FF, it's a blank page.
+		 * Not error.
+		 */
+		if ((reg_val & BCH_DEC_STATUS_FAIL_SEC_FLAG_MASK) &&
+				!blank_check(databuf, a_len))
+			return_val |= ECC_DATA_ERROR;
+	}
+
+	if ((reg_val & DEC_STATUS_B_ECC_FAIL) && oobbuf) {
+		reg_val = readl(&reg->bch_dec_status_buf);
+		/*
+		 * If uncorrectable error occurs on tag area, then see whether
+		 * they are all FF. If all are FF, it's a blank page.
+		 * Not error.
+		 */
+		if ((reg_val & BCH_DEC_STATUS_FAIL_TAG_MASK) &&
+				!blank_check(oobbuf, b_len))
+			return_val |= ECC_TAG_ERROR;
+	}
+
+	return return_val;
+}
+
+/**
+ * Set GO bit to send command to device
+ *
+ * @param reg	nand_ctlr structure
+ */
+static void start_command(struct nand_ctlr *reg)
+{
+	u32 reg_val;
+
+	reg_val = readl(&reg->command);
+	reg_val |= CMD_GO;
+	writel(reg_val, &reg->command);
+}
+
+/**
+ * Clear command GO bit, DMA GO bit, and DMA completion status
+ *
+ * @param reg	nand_ctlr structure
+ */
+static void stop_command(struct nand_ctlr *reg)
+{
+	/* Stop command */
+	writel(0, &reg->command);
+
+	/* Stop DMA engine and clear DMA completion status */
+	writel(DMA_MST_CTRL_GO_DISABLE
+		| DMA_MST_CTRL_IS_DMA_DONE,
+		&reg->dma_mst_ctrl);
+}
+
+/**
+ * Set up NAND bus width and page size
+ *
+ * @param info		nand_info structure
+ * @param *reg_val	address of reg_val
+ * @return 0 if ok, -1 on error
+ */
+static int set_bus_width_page_size(struct fdt_nand *config,
+	u32 *reg_val)
+{
+	if (config->width == 8)
+		*reg_val = CFG_BUS_WIDTH_8BIT;
+	else if (config->width == 16)
+		*reg_val = CFG_BUS_WIDTH_16BIT;
+	else {
+		debug("%s: Unsupported bus width %d\n", __func__,
+		      config->width);
+		return -1;
+	}
+
+	if (our_mtd->writesize == 512)
+		*reg_val |= CFG_PAGE_SIZE_512;
+	else if (our_mtd->writesize == 2048)
+		*reg_val |= CFG_PAGE_SIZE_2048;
+	else if (our_mtd->writesize == 4096)
+		*reg_val |= CFG_PAGE_SIZE_4096;
+	else {
+		debug("%s: Unsupported page size %d\n", __func__,
+		      our_mtd->writesize);
+		return -1;
+	}
+
+	return 0;
+}
+
+/**
+ * Page read/write function
+ *
+ * @param mtd		mtd info structure
+ * @param chip		nand chip info structure
+ * @param buf		data buffer
+ * @param page		page number
+ * @param with_ecc	1 to enable ECC, 0 to disable ECC
+ * @param is_writing	0 for read, 1 for write
+ * @return	0 when successfully completed
+ *		-EIO when command timeout
+ */
+static int nand_rw_page(struct mtd_info *mtd, struct nand_chip *chip,
+	uint8_t *buf, int page, int with_ecc, int is_writing)
+{
+	u32 reg_val;
+	int tag_size;
+	struct nand_oobfree *free = chip->ecc.layout->oobfree;
+	/* 4*128=512 (byte) is the value that our HW can support. */
+	ALLOC_CACHE_ALIGN_BUFFER(u32, tag_buf, 128);
+	char *tag_ptr;
+	struct nand_drv *info;
+	struct fdt_nand *config;
+
+	if ((uintptr_t)buf & 0x03) {
+		printf("buf %p has to be 4-byte aligned\n", buf);
+		return -EINVAL;
+	}
+
+	info = (struct nand_drv *)chip->priv;
+	config = &info->config;
+	if (set_bus_width_page_size(config, &reg_val))
+		return -EINVAL;
+
+	/* Need to be 4-byte aligned */
+	tag_ptr = (char *)tag_buf;
+
+	stop_command(info->reg);
+
+	writel((1 << chip->page_shift) - 1, &info->reg->dma_cfg_a);
+	writel(virt_to_phys(buf), &info->reg->data_block_ptr);
+
+	if (with_ecc) {
+		writel(virt_to_phys(tag_ptr), &info->reg->tag_ptr);
+		if (is_writing)
+			memcpy(tag_ptr, chip->oob_poi + free->offset,
+				chip->ecc.layout->oobavail +
+				TAG_ECC_BYTES);
+	} else {
+		writel(virt_to_phys(chip->oob_poi), &info->reg->tag_ptr);
+	}
+
+	/* Set ECC selection, configure ECC settings */
+	if (with_ecc) {
+		tag_size = chip->ecc.layout->oobavail + TAG_ECC_BYTES;
+		reg_val |= (CFG_SKIP_SPARE_SEL_4
+			| CFG_SKIP_SPARE_ENABLE
+			| CFG_HW_ECC_CORRECTION_ENABLE
+			| CFG_ECC_EN_TAG_DISABLE
+			| CFG_HW_ECC_SEL_RS
+			| CFG_HW_ECC_ENABLE
+			| CFG_TVAL4
+			| (tag_size - 1));
+
+		if (!is_writing)
+			tag_size += SKIPPED_SPARE_BYTES;
+		dma_prepare(tag_ptr, tag_size, is_writing);
+	} else {
+		tag_size = mtd->oobsize;
+		reg_val |= (CFG_SKIP_SPARE_DISABLE
+			| CFG_HW_ECC_CORRECTION_DISABLE
+			| CFG_ECC_EN_TAG_DISABLE
+			| CFG_HW_ECC_DISABLE
+			| (tag_size - 1));
+		dma_prepare(chip->oob_poi, tag_size, is_writing);
+	}
+	writel(reg_val, &info->reg->config);
+
+	dma_prepare(buf, 1 << chip->page_shift, is_writing);
+
+	writel(BCH_CONFIG_BCH_ECC_DISABLE, &info->reg->bch_config);
+
+	writel(tag_size - 1, &info->reg->dma_cfg_b);
+
+	nand_clear_interrupt_status(info->reg);
+
+	reg_val = CMD_CLE | CMD_ALE
+		| CMD_SEC_CMD
+		| (CMD_ALE_BYTES5 << CMD_ALE_BYTE_SIZE_SHIFT)
+		| CMD_A_VALID
+		| CMD_B_VALID
+		| (CMD_TRANS_SIZE_PAGE << CMD_TRANS_SIZE_SHIFT)
+		| CMD_CE0;
+	if (!is_writing)
+		reg_val |= (CMD_AFT_DAT_DISABLE | CMD_RX);
+	else
+		reg_val |= (CMD_AFT_DAT_ENABLE | CMD_TX);
+	writel(reg_val, &info->reg->command);
+
+	/* Setup DMA engine */
+	reg_val = DMA_MST_CTRL_GO_ENABLE
+		| DMA_MST_CTRL_BURST_8WORDS
+		| DMA_MST_CTRL_EN_A_ENABLE
+		| DMA_MST_CTRL_EN_B_ENABLE;
+
+	if (!is_writing)
+		reg_val |= DMA_MST_CTRL_DIR_READ;
+	else
+		reg_val |= DMA_MST_CTRL_DIR_WRITE;
+
+	writel(reg_val, &info->reg->dma_mst_ctrl);
+
+	start_command(info->reg);
+
+	if (!nand_waitfor_cmd_completion(info->reg)) {
+		if (!is_writing)
+			printf("Read Page 0x%X timeout ", page);
+		else
+			printf("Write Page 0x%X timeout ", page);
+		if (with_ecc)
+			printf("with ECC");
+		else
+			printf("without ECC");
+		printf("\n");
+		return -EIO;
+	}
+
+	if (with_ecc && !is_writing) {
+		memcpy(chip->oob_poi, tag_ptr,
+			SKIPPED_SPARE_BYTES);
+		memcpy(chip->oob_poi + free->offset,
+			tag_ptr + SKIPPED_SPARE_BYTES,
+			chip->ecc.layout->oobavail);
+		reg_val = (u32)check_ecc_error(info->reg, (u8 *)buf,
+			1 << chip->page_shift,
+			(u8 *)(tag_ptr + SKIPPED_SPARE_BYTES),
+			chip->ecc.layout->oobavail);
+		if (reg_val & ECC_TAG_ERROR)
+			printf("Read Page 0x%X tag ECC error\n", page);
+		if (reg_val & ECC_DATA_ERROR)
+			printf("Read Page 0x%X data ECC error\n",
+				page);
+		if (reg_val & (ECC_DATA_ERROR | ECC_TAG_ERROR))
+			return -EIO;
+	}
+	return 0;
+}
+
+/**
+ * Hardware ecc based page read function
+ *
+ * @param mtd	mtd info structure
+ * @param chip	nand chip info structure
+ * @param buf	buffer to store read data
+ * @param page	page number to read
+ * @return	0 when successfully completed
+ *		-EIO when command timeout
+ */
+static int nand_read_page_hwecc(struct mtd_info *mtd,
+	struct nand_chip *chip, uint8_t *buf, int page)
+{
+	return nand_rw_page(mtd, chip, buf, page, 1, 0);
+}
+
+/**
+ * Hardware ecc based page write function
+ *
+ * @param mtd	mtd info structure
+ * @param chip	nand chip info structure
+ * @param buf	data buffer
+ */
+static void nand_write_page_hwecc(struct mtd_info *mtd,
+	struct nand_chip *chip, const uint8_t *buf)
+{
+	int page;
+	struct nand_drv *info;
+
+	info = (struct nand_drv *)chip->priv;
+
+	page = (readl(&info->reg->addr_reg1) >> 16) |
+		(readl(&info->reg->addr_reg2) << 16);
+
+	nand_rw_page(mtd, chip, (uint8_t *)buf, page, 1, 1);
+}
+
+
+/**
+ * Read raw page data without ecc
+ *
+ * @param mtd	mtd info structure
+ * @param chip	nand chip info structure
+ * @param buf	buffer to store read data
+ * @param page	page number to read
+ * @return	0 when successfully completed
+ *		-EINVAL when chip->oob_poi is not double-word aligned
+ *		-EIO when command timeout
+ */
+static int nand_read_page_raw(struct mtd_info *mtd,
+	struct nand_chip *chip, uint8_t *buf, int page)
+{
+	return nand_rw_page(mtd, chip, buf, page, 0, 0);
+}
+
+/**
+ * Raw page write function
+ *
+ * @param mtd	mtd info structure
+ * @param chip	nand chip info structure
+ * @param buf	data buffer
+ */
+static void nand_write_page_raw(struct mtd_info *mtd,
+		struct nand_chip *chip,	const uint8_t *buf)
+{
+	int page;
+	struct nand_drv *info;
+
+	info = (struct nand_drv *)chip->priv;
+	page = (readl(&info->reg->addr_reg1) >> 16) |
+		(readl(&info->reg->addr_reg2) << 16);
+
+	nand_rw_page(mtd, chip, (uint8_t *)buf, page, 0, 1);
+}
+
+/**
+ * OOB data read/write function
+ *
+ * @param mtd		mtd info structure
+ * @param chip		nand chip info structure
+ * @param page		page number to read
+ * @param with_ecc	1 to enable ECC, 0 to disable ECC
+ * @param is_writing	0 for read, 1 for write
+ * @return	0 when successfully completed
+ *		-EINVAL when chip->oob_poi is not double-word aligned
+ *		-EIO when command timeout
+ */
+static int nand_rw_oob(struct mtd_info *mtd, struct nand_chip *chip,
+	int page, int with_ecc, int is_writing)
+{
+	u32 reg_val;
+	int tag_size;
+	struct nand_oobfree *free = chip->ecc.layout->oobfree;
+	struct nand_drv *info;
+
+	if (((int)chip->oob_poi) & 0x03)
+		return -EINVAL;
+	info = (struct nand_drv *)chip->priv;
+	if (set_bus_width_page_size(&info->config, &reg_val))
+		return -EINVAL;
+
+	stop_command(info->reg);
+
+	writel(virt_to_phys(chip->oob_poi), &info->reg->tag_ptr);
+
+	/* Set ECC selection */
+	tag_size = mtd->oobsize;
+	if (with_ecc)
+		reg_val |= CFG_ECC_EN_TAG_ENABLE;
+	else
+		reg_val |= (CFG_ECC_EN_TAG_DISABLE);
+
+	reg_val |= ((tag_size - 1) |
+		CFG_SKIP_SPARE_DISABLE |
+		CFG_HW_ECC_CORRECTION_DISABLE |
+		CFG_HW_ECC_DISABLE);
+	writel(reg_val, &info->reg->config);
+
+	dma_prepare(chip->oob_poi, tag_size, is_writing);
+
+	writel(BCH_CONFIG_BCH_ECC_DISABLE, &info->reg->bch_config);
+
+	if (is_writing && with_ecc)
+		tag_size -= TAG_ECC_BYTES;
+
+	writel(tag_size - 1, &info->reg->dma_cfg_b);
+
+	nand_clear_interrupt_status(info->reg);
+
+	reg_val = CMD_CLE | CMD_ALE
+		| CMD_SEC_CMD
+		| (CMD_ALE_BYTES5 << CMD_ALE_BYTE_SIZE_SHIFT)
+		| CMD_B_VALID
+		| CMD_CE0;
+	if (!is_writing)
+		reg_val |= (CMD_AFT_DAT_DISABLE | CMD_RX);
+	else
+		reg_val |= (CMD_AFT_DAT_ENABLE | CMD_TX);
+	writel(reg_val, &info->reg->command);
+
+	/* Setup DMA engine */
+	reg_val = DMA_MST_CTRL_GO_ENABLE
+		| DMA_MST_CTRL_BURST_8WORDS
+		| DMA_MST_CTRL_EN_B_ENABLE;
+	if (!is_writing)
+		reg_val |= DMA_MST_CTRL_DIR_READ;
+	else
+		reg_val |= DMA_MST_CTRL_DIR_WRITE;
+
+	writel(reg_val, &info->reg->dma_mst_ctrl);
+
+	start_command(info->reg);
+
+	if (!nand_waitfor_cmd_completion(info->reg)) {
+		if (!is_writing)
+			printf("Read OOB of Page 0x%X timeout\n", page);
+		else
+			printf("Write OOB of Page 0x%X timeout\n", page);
+		return -EIO;
+	}
+
+	if (with_ecc && !is_writing) {
+		reg_val = (u32)check_ecc_error(info->reg, 0, 0,
+			(u8 *)(chip->oob_poi + free->offset),
+			chip->ecc.layout->oobavail);
+		if (reg_val & ECC_TAG_ERROR)
+			printf("Read OOB of Page 0x%X tag ECC error\n", page);
+	}
+	return 0;
+}
+
+/**
+ * OOB data read function
+ *
+ * @param mtd		mtd info structure
+ * @param chip		nand chip info structure
+ * @param page		page number to read
+ * @param sndcmd	flag whether to issue read command or not
+ * @return	1 - issue read command next time
+ *		0 - not to issue
+ */
+static int nand_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
+	int page, int sndcmd)
+{
+	if (sndcmd) {
+		chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
+		sndcmd = 0;
+	}
+	nand_rw_oob(mtd, chip, page, 0, 0);
+	return sndcmd;
+}
+
+/**
+ * OOB data write function
+ *
+ * @param mtd	mtd info structure
+ * @param chip	nand chip info structure
+ * @param page	page number to write
+ * @return	0 when successfully completed
+ *		-EINVAL when chip->oob_poi is not double-word aligned
+ *		-EIO when command timeout
+ */
+static int nand_write_oob(struct mtd_info *mtd, struct nand_chip *chip,
+	int page)
+{
+	chip->cmdfunc(mtd, NAND_CMD_SEQIN, mtd->writesize, page);
+
+	return nand_rw_oob(mtd, chip, page, 0, 1);
+}
+
+/**
+ * Set up NAND memory timings according to the provided parameters
+ *
+ * @param timing	Timing parameters
+ * @param reg		NAND controller register address
+ */
+static void setup_timing(unsigned timing[FDT_NAND_TIMING_COUNT],
+			 struct nand_ctlr *reg)
+{
+	u32 reg_val, clk_rate, clk_period, time_val;
+
+	clk_rate = (u32)clock_get_periph_rate(PERIPH_ID_NDFLASH,
+		CLOCK_ID_PERIPH) / 1000000;
+	clk_period = 1000 / clk_rate;
+	reg_val = ((timing[FDT_NAND_MAX_TRP_TREA] / clk_period) <<
+		TIMING_TRP_RESP_CNT_SHIFT) & TIMING_TRP_RESP_CNT_MASK;
+	reg_val |= ((timing[FDT_NAND_TWB] / clk_period) <<
+		TIMING_TWB_CNT_SHIFT) & TIMING_TWB_CNT_MASK;
+	time_val = timing[FDT_NAND_MAX_TCR_TAR_TRR] / clk_period;
+	if (time_val > 2)
+		reg_val |= ((time_val - 2) << TIMING_TCR_TAR_TRR_CNT_SHIFT) &
+			TIMING_TCR_TAR_TRR_CNT_MASK;
+	reg_val |= ((timing[FDT_NAND_TWHR] / clk_period) <<
+		TIMING_TWHR_CNT_SHIFT) & TIMING_TWHR_CNT_MASK;
+	time_val = timing[FDT_NAND_MAX_TCS_TCH_TALS_TALH] / clk_period;
+	if (time_val > 1)
+		reg_val |= ((time_val - 1) << TIMING_TCS_CNT_SHIFT) &
+			TIMING_TCS_CNT_MASK;
+	reg_val |= ((timing[FDT_NAND_TWH] / clk_period) <<
+		TIMING_TWH_CNT_SHIFT) & TIMING_TWH_CNT_MASK;
+	reg_val |= ((timing[FDT_NAND_TWP] / clk_period) <<
+		TIMING_TWP_CNT_SHIFT) & TIMING_TWP_CNT_MASK;
+	reg_val |= ((timing[FDT_NAND_TRH] / clk_period) <<
+		TIMING_TRH_CNT_SHIFT) & TIMING_TRH_CNT_MASK;
+	reg_val |= ((timing[FDT_NAND_MAX_TRP_TREA] / clk_period) <<
+		TIMING_TRP_CNT_SHIFT) & TIMING_TRP_CNT_MASK;
+	writel(reg_val, &reg->timing);
+
+	reg_val = 0;
+	time_val = timing[FDT_NAND_TADL] / clk_period;
+	if (time_val > 2)
+		reg_val = (time_val - 2) & TIMING2_TADL_CNT_MASK;
+	writel(reg_val, &reg->timing2);
+}
+
+/**
+ * Decode NAND parameters from the device tree
+ *
+ * @param blob	Device tree blob
+ * @param node	Node containing "nand-flash" compatble node
+ * @return 0 if ok, -ve on error (FDT_ERR_...)
+ */
+static int fdt_decode_nand(const void *blob, int node, struct fdt_nand *config)
+{
+	int err;
+
+	config->reg = (struct nand_ctlr *)fdtdec_get_addr(blob, node, "reg");
+	config->enabled = fdtdec_get_is_enabled(blob, node);
+	config->width = fdtdec_get_int(blob, node, "nvidia,nand-width", 8);
+	err = fdtdec_decode_gpio(blob, node, "nvidia,wp-gpios",
+				 &config->wp_gpio);
+	if (err)
+		return err;
+	err = fdtdec_get_int_array(blob, node, "nvidia,timing",
+			config->timing, FDT_NAND_TIMING_COUNT);
+	if (err < 0)
+		return err;
+
+	/* Now look up the controller and decode that */
+	node = fdt_next_node(blob, node, NULL);
+	if (node < 0)
+		return node;
+
+	return 0;
+}
+
+/**
+ * Board-specific NAND initialization
+ *
+ * @param nand	nand chip info structure
+ * @return 0, after initialized, -1 on error
+ */
+int tegra_nand_init(struct nand_chip *nand, int devnum)
+{
+	struct nand_drv *info = &nand_ctrl;
+	struct fdt_nand *config = &info->config;
+	int node, ret;
+
+	node = fdtdec_next_compatible(gd->fdt_blob, 0,
+				      COMPAT_NVIDIA_TEGRA20_NAND);
+	if (node < 0)
+		return -1;
+	if (fdt_decode_nand(gd->fdt_blob, node, config)) {
+		printf("Could not decode nand-flash in device tree\n");
+		return -1;
+	}
+	if (!config->enabled)
+		return -1;
+	info->reg = config->reg;
+	nand->ecc.mode = NAND_ECC_HW;
+	nand->ecc.layout = &eccoob;
+
+	nand->options = LP_OPTIONS;
+	nand->cmdfunc = nand_command;
+	nand->read_byte = read_byte;
+	nand->ecc.read_page = nand_read_page_hwecc;
+	nand->ecc.write_page = nand_write_page_hwecc;
+	nand->ecc.read_page_raw = nand_read_page_raw;
+	nand->ecc.write_page_raw = nand_write_page_raw;
+	nand->ecc.read_oob = nand_read_oob;
+	nand->ecc.write_oob = nand_write_oob;
+	nand->select_chip = nand_select_chip;
+	nand->dev_ready  = nand_dev_ready;
+	nand->priv = &nand_ctrl;
+
+	/* Adjust controller clock rate */
+	clock_start_periph_pll(PERIPH_ID_NDFLASH, CLOCK_ID_PERIPH, 52000000);
+
+	/* Adjust timing for NAND device */
+	setup_timing(config->timing, info->reg);
+
+	funcmux_select(PERIPH_ID_NDFLASH, FUNCMUX_DEFAULT);
+	fdtdec_setup_gpio(&config->wp_gpio);
+	gpio_direction_output(config->wp_gpio.gpio, 1);
+
+	our_mtd = &nand_info[devnum];
+	our_mtd->priv = nand;
+	ret = nand_scan_ident(our_mtd, CONFIG_SYS_NAND_MAX_CHIPS, NULL);
+	if (ret)
+		return ret;
+
+	nand->ecc.size = our_mtd->writesize;
+	nand->ecc.bytes = our_mtd->oobsize;
+
+	ret = nand_scan_tail(our_mtd);
+	if (ret)
+		return ret;
+
+	ret = nand_register(devnum);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+void board_nand_init(void)
+{
+	struct nand_chip *nand = &nand_chip[0];
+
+	if (tegra_nand_init(nand, 0))
+		puts("Tegra NAND init failed\n");
+}