nand/denali: Adding Denali NAND driver support

To add the Denali NAND driver support into U-Boot.
This driver is leveraged from Linux with commit ID
fdbad98dff8007f2b8bee6698b5d25ebba0471c9. For Denali
controller 64 variance, you need to declare macro
CONFIG_SYS_NAND_DENALI_64BIT.

Signed-off-by: Chin Liang See <clsee@altera.com>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reviewed-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

1 files changed, 1205 insertions, 0 deletions

diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c
new file mode 100644
index 0000000..ba3de1a
--- /dev/null
+++ b/drivers/mtd/nand/denali.c
@@ -0,0 +1,1205 @@
+/*
+ * Copyright (C) 2014       Panasonic Corporation
+ * Copyright (C) 2013-2014, Altera Corporation <www.altera.com>
+ * Copyright (C) 2009-2010, Intel Corporation and its suppliers.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <nand.h>
+#include <asm/errno.h>
+#include <asm/io.h>
+
+#include "denali.h"
+
+#define NAND_DEFAULT_TIMINGS	-1
+
+static int onfi_timing_mode = NAND_DEFAULT_TIMINGS;
+
+/* We define a macro here that combines all interrupts this driver uses into
+ * a single constant value, for convenience. */
+#define DENALI_IRQ_ALL	(INTR_STATUS__DMA_CMD_COMP | \
+			INTR_STATUS__ECC_TRANSACTION_DONE | \
+			INTR_STATUS__ECC_ERR | \
+			INTR_STATUS__PROGRAM_FAIL | \
+			INTR_STATUS__LOAD_COMP | \
+			INTR_STATUS__PROGRAM_COMP | \
+			INTR_STATUS__TIME_OUT | \
+			INTR_STATUS__ERASE_FAIL | \
+			INTR_STATUS__RST_COMP | \
+			INTR_STATUS__ERASE_COMP | \
+			INTR_STATUS__ECC_UNCOR_ERR | \
+			INTR_STATUS__INT_ACT | \
+			INTR_STATUS__LOCKED_BLK)
+
+/* indicates whether or not the internal value for the flash bank is
+ * valid or not */
+#define CHIP_SELECT_INVALID	-1
+
+#define SUPPORT_8BITECC		1
+
+/*
+ * this macro allows us to convert from an MTD structure to our own
+ * device context (denali) structure.
+ */
+#define mtd_to_denali(m) (((struct nand_chip *)mtd->priv)->priv)
+
+/* These constants are defined by the driver to enable common driver
+ * configuration options. */
+#define SPARE_ACCESS		0x41
+#define MAIN_ACCESS		0x42
+#define MAIN_SPARE_ACCESS	0x43
+
+#define DENALI_UNLOCK_START	0x10
+#define DENALI_UNLOCK_END	0x11
+#define DENALI_LOCK		0x21
+#define DENALI_LOCK_TIGHT	0x31
+#define DENALI_BUFFER_LOAD	0x60
+#define DENALI_BUFFER_WRITE	0x62
+
+#define DENALI_READ	0
+#define DENALI_WRITE	0x100
+
+/* types of device accesses. We can issue commands and get status */
+#define COMMAND_CYCLE	0
+#define ADDR_CYCLE	1
+#define STATUS_CYCLE	2
+
+/* this is a helper macro that allows us to
+ * format the bank into the proper bits for the controller */
+#define BANK(x) ((x) << 24)
+
+/* Interrupts are cleared by writing a 1 to the appropriate status bit */
+static inline void clear_interrupt(struct denali_nand_info *denali,
+							uint32_t irq_mask)
+{
+	uint32_t intr_status_reg;
+
+	intr_status_reg = INTR_STATUS(denali->flash_bank);
+
+	writel(irq_mask, denali->flash_reg + intr_status_reg);
+}
+
+static uint32_t read_interrupt_status(struct denali_nand_info *denali)
+{
+	uint32_t intr_status_reg;
+
+	intr_status_reg = INTR_STATUS(denali->flash_bank);
+
+	return readl(denali->flash_reg + intr_status_reg);
+}
+
+static void clear_interrupts(struct denali_nand_info *denali)
+{
+	uint32_t status;
+
+	status = read_interrupt_status(denali);
+	clear_interrupt(denali, status);
+
+	denali->irq_status = 0;
+}
+
+static void denali_irq_enable(struct denali_nand_info *denali,
+							uint32_t int_mask)
+{
+	int i;
+
+	for (i = 0; i < denali->max_banks; ++i)
+		writel(int_mask, denali->flash_reg + INTR_EN(i));
+}
+
+static uint32_t wait_for_irq(struct denali_nand_info *denali, uint32_t irq_mask)
+{
+	unsigned long timeout = 1000000;
+	uint32_t intr_status;
+
+	do {
+		intr_status = read_interrupt_status(denali) & DENALI_IRQ_ALL;
+		if (intr_status & irq_mask) {
+			denali->irq_status &= ~irq_mask;
+			/* our interrupt was detected */
+			break;
+		}
+		udelay(1);
+		timeout--;
+	} while (timeout != 0);
+
+	if (timeout == 0) {
+		/* timeout */
+		printf("Denali timeout with interrupt status %08x\n",
+		       read_interrupt_status(denali));
+		intr_status = 0;
+	}
+	return intr_status;
+}
+
+/*
+ * Certain operations for the denali NAND controller use an indexed mode to
+ * read/write data. The operation is performed by writing the address value
+ * of the command to the device memory followed by the data. This function
+ * abstracts this common operation.
+*/
+static void index_addr(struct denali_nand_info *denali,
+				uint32_t address, uint32_t data)
+{
+	writel(address, denali->flash_mem + INDEX_CTRL_REG);
+	writel(data, denali->flash_mem + INDEX_DATA_REG);
+}
+
+/* Perform an indexed read of the device */
+static void index_addr_read_data(struct denali_nand_info *denali,
+				 uint32_t address, uint32_t *pdata)
+{
+	writel(address, denali->flash_mem + INDEX_CTRL_REG);
+	*pdata = readl(denali->flash_mem + INDEX_DATA_REG);
+}
+
+/* We need to buffer some data for some of the NAND core routines.
+ * The operations manage buffering that data. */
+static void reset_buf(struct denali_nand_info *denali)
+{
+	denali->buf.head = 0;
+	denali->buf.tail = 0;
+}
+
+static void write_byte_to_buf(struct denali_nand_info *denali, uint8_t byte)
+{
+	denali->buf.buf[denali->buf.tail++] = byte;
+}
+
+/* resets a specific device connected to the core */
+static void reset_bank(struct denali_nand_info *denali)
+{
+	uint32_t irq_status;
+	uint32_t irq_mask = INTR_STATUS__RST_COMP |
+			    INTR_STATUS__TIME_OUT;
+
+	clear_interrupts(denali);
+
+	writel(1 << denali->flash_bank, denali->flash_reg + DEVICE_RESET);
+
+	irq_status = wait_for_irq(denali, irq_mask);
+	if (irq_status & INTR_STATUS__TIME_OUT)
+		debug("reset bank failed.\n");
+}
+
+/* Reset the flash controller */
+static uint32_t denali_nand_reset(struct denali_nand_info *denali)
+{
+	uint32_t i;
+
+	for (i = 0; i < denali->max_banks; i++)
+		writel(INTR_STATUS__RST_COMP | INTR_STATUS__TIME_OUT,
+		       denali->flash_reg + INTR_STATUS(i));
+
+	for (i = 0; i < denali->max_banks; i++) {
+		writel(1 << i, denali->flash_reg + DEVICE_RESET);
+		while (!(readl(denali->flash_reg + INTR_STATUS(i)) &
+			(INTR_STATUS__RST_COMP | INTR_STATUS__TIME_OUT)))
+			if (readl(denali->flash_reg + INTR_STATUS(i)) &
+				INTR_STATUS__TIME_OUT)
+				debug("NAND Reset operation timed out on bank"
+				      " %d\n", i);
+	}
+
+	for (i = 0; i < denali->max_banks; i++)
+		writel(INTR_STATUS__RST_COMP | INTR_STATUS__TIME_OUT,
+		       denali->flash_reg + INTR_STATUS(i));
+
+	return 0;
+}
+
+/*
+ * this routine calculates the ONFI timing values for a given mode and
+ * programs the clocking register accordingly. The mode is determined by
+ * the get_onfi_nand_para routine.
+ */
+static void nand_onfi_timing_set(struct denali_nand_info *denali,
+								uint16_t mode)
+{
+	uint32_t trea[6] = {40, 30, 25, 20, 20, 16};
+	uint32_t trp[6] = {50, 25, 17, 15, 12, 10};
+	uint32_t treh[6] = {30, 15, 15, 10, 10, 7};
+	uint32_t trc[6] = {100, 50, 35, 30, 25, 20};
+	uint32_t trhoh[6] = {0, 15, 15, 15, 15, 15};
+	uint32_t trloh[6] = {0, 0, 0, 0, 5, 5};
+	uint32_t tcea[6] = {100, 45, 30, 25, 25, 25};
+	uint32_t tadl[6] = {200, 100, 100, 100, 70, 70};
+	uint32_t trhw[6] = {200, 100, 100, 100, 100, 100};
+	uint32_t trhz[6] = {200, 100, 100, 100, 100, 100};
+	uint32_t twhr[6] = {120, 80, 80, 60, 60, 60};
+	uint32_t tcs[6] = {70, 35, 25, 25, 20, 15};
+
+	uint32_t tclsrising = 1;
+	uint32_t data_invalid_rhoh, data_invalid_rloh, data_invalid;
+	uint32_t dv_window = 0;
+	uint32_t en_lo, en_hi;
+	uint32_t acc_clks;
+	uint32_t addr_2_data, re_2_we, re_2_re, we_2_re, cs_cnt;
+
+	en_lo = DIV_ROUND_UP(trp[mode], CLK_X);
+	en_hi = DIV_ROUND_UP(treh[mode], CLK_X);
+	if ((en_hi * CLK_X) < (treh[mode] + 2))
+		en_hi++;
+
+	if ((en_lo + en_hi) * CLK_X < trc[mode])
+		en_lo += DIV_ROUND_UP((trc[mode] - (en_lo + en_hi) * CLK_X),
+				      CLK_X);
+
+	if ((en_lo + en_hi) < CLK_MULTI)
+		en_lo += CLK_MULTI - en_lo - en_hi;
+
+	while (dv_window < 8) {
+		data_invalid_rhoh = en_lo * CLK_X + trhoh[mode];
+
+		data_invalid_rloh = (en_lo + en_hi) * CLK_X + trloh[mode];
+
+		data_invalid =
+		    data_invalid_rhoh <
+		    data_invalid_rloh ? data_invalid_rhoh : data_invalid_rloh;
+
+		dv_window = data_invalid - trea[mode];
+
+		if (dv_window < 8)
+			en_lo++;
+	}
+
+	acc_clks = DIV_ROUND_UP(trea[mode], CLK_X);
+
+	while (((acc_clks * CLK_X) - trea[mode]) < 3)
+		acc_clks++;
+
+	if ((data_invalid - acc_clks * CLK_X) < 2)
+		debug("%s, Line %d: Warning!\n", __FILE__, __LINE__);
+
+	addr_2_data = DIV_ROUND_UP(tadl[mode], CLK_X);
+	re_2_we = DIV_ROUND_UP(trhw[mode], CLK_X);
+	re_2_re = DIV_ROUND_UP(trhz[mode], CLK_X);
+	we_2_re = DIV_ROUND_UP(twhr[mode], CLK_X);
+	cs_cnt = DIV_ROUND_UP((tcs[mode] - trp[mode]), CLK_X);
+	if (!tclsrising)
+		cs_cnt = DIV_ROUND_UP(tcs[mode], CLK_X);
+	if (cs_cnt == 0)
+		cs_cnt = 1;
+
+	if (tcea[mode]) {
+		while (((cs_cnt * CLK_X) + trea[mode]) < tcea[mode])
+			cs_cnt++;
+	}
+
+	/* Sighting 3462430: Temporary hack for MT29F128G08CJABAWP:B */
+	if ((readl(denali->flash_reg + MANUFACTURER_ID) == 0) &&
+	    (readl(denali->flash_reg + DEVICE_ID) == 0x88))
+		acc_clks = 6;
+
+	writel(acc_clks, denali->flash_reg + ACC_CLKS);
+	writel(re_2_we, denali->flash_reg + RE_2_WE);
+	writel(re_2_re, denali->flash_reg + RE_2_RE);
+	writel(we_2_re, denali->flash_reg + WE_2_RE);
+	writel(addr_2_data, denali->flash_reg + ADDR_2_DATA);
+	writel(en_lo, denali->flash_reg + RDWR_EN_LO_CNT);
+	writel(en_hi, denali->flash_reg + RDWR_EN_HI_CNT);
+	writel(cs_cnt, denali->flash_reg + CS_SETUP_CNT);
+}
+
+/* queries the NAND device to see what ONFI modes it supports. */
+static uint32_t get_onfi_nand_para(struct denali_nand_info *denali)
+{
+	int i;
+	/*
+	 * we needn't to do a reset here because driver has already
+	 * reset all the banks before
+	 */
+	if (!(readl(denali->flash_reg + ONFI_TIMING_MODE) &
+	    ONFI_TIMING_MODE__VALUE))
+		return -EIO;
+
+	for (i = 5; i > 0; i--) {
+		if (readl(denali->flash_reg + ONFI_TIMING_MODE) &
+			(0x01 << i))
+			break;
+	}
+
+	nand_onfi_timing_set(denali, i);
+
+	/* By now, all the ONFI devices we know support the page cache */
+	/* rw feature. So here we enable the pipeline_rw_ahead feature */
+	return 0;
+}
+
+static void get_samsung_nand_para(struct denali_nand_info *denali,
+							uint8_t device_id)
+{
+	if (device_id == 0xd3) { /* Samsung K9WAG08U1A */
+		/* Set timing register values according to datasheet */
+		writel(5, denali->flash_reg + ACC_CLKS);
+		writel(20, denali->flash_reg + RE_2_WE);
+		writel(12, denali->flash_reg + WE_2_RE);
+		writel(14, denali->flash_reg + ADDR_2_DATA);
+		writel(3, denali->flash_reg + RDWR_EN_LO_CNT);
+		writel(2, denali->flash_reg + RDWR_EN_HI_CNT);
+		writel(2, denali->flash_reg + CS_SETUP_CNT);
+	}
+}
+
+static void get_toshiba_nand_para(struct denali_nand_info *denali)
+{
+	uint32_t tmp;
+
+	/* Workaround to fix a controller bug which reports a wrong */
+	/* spare area size for some kind of Toshiba NAND device */
+	if ((readl(denali->flash_reg + DEVICE_MAIN_AREA_SIZE) == 4096) &&
+	    (readl(denali->flash_reg + DEVICE_SPARE_AREA_SIZE) == 64)) {
+		writel(216, denali->flash_reg + DEVICE_SPARE_AREA_SIZE);
+		tmp = readl(denali->flash_reg + DEVICES_CONNECTED) *
+			readl(denali->flash_reg + DEVICE_SPARE_AREA_SIZE);
+		writel(tmp, denali->flash_reg + LOGICAL_PAGE_SPARE_SIZE);
+	}
+}
+
+static void get_hynix_nand_para(struct denali_nand_info *denali,
+							uint8_t device_id)
+{
+	uint32_t main_size, spare_size;
+
+	switch (device_id) {
+	case 0xD5: /* Hynix H27UAG8T2A, H27UBG8U5A or H27UCG8VFA */
+	case 0xD7: /* Hynix H27UDG8VEM, H27UCG8UDM or H27UCG8V5A */
+		writel(128, denali->flash_reg + PAGES_PER_BLOCK);
+		writel(4096, denali->flash_reg + DEVICE_MAIN_AREA_SIZE);
+		writel(224, denali->flash_reg + DEVICE_SPARE_AREA_SIZE);
+		main_size = 4096 *
+			readl(denali->flash_reg + DEVICES_CONNECTED);
+		spare_size = 224 *
+			readl(denali->flash_reg + DEVICES_CONNECTED);
+		writel(main_size, denali->flash_reg + LOGICAL_PAGE_DATA_SIZE);
+		writel(spare_size, denali->flash_reg + LOGICAL_PAGE_SPARE_SIZE);
+		writel(0, denali->flash_reg + DEVICE_WIDTH);
+		break;
+	default:
+		debug("Spectra: Unknown Hynix NAND (Device ID: 0x%x)."
+		      "Will use default parameter values instead.\n",
+		      device_id);
+	}
+}
+
+/*
+ * determines how many NAND chips are connected to the controller. Note for
+ * Intel CE4100 devices we don't support more than one device.
+ */
+static void find_valid_banks(struct denali_nand_info *denali)
+{
+	uint32_t id[denali->max_banks];
+	int i;
+
+	denali->total_used_banks = 1;
+	for (i = 0; i < denali->max_banks; i++) {
+		index_addr(denali, (uint32_t)(MODE_11 | (i << 24) | 0), 0x90);
+		index_addr(denali, (uint32_t)(MODE_11 | (i << 24) | 1), 0);
+		index_addr_read_data(denali,
+				     (uint32_t)(MODE_11 | (i << 24) | 2),
+				     &id[i]);
+
+		if (i == 0) {
+			if (!(id[i] & 0x0ff))
+				break;
+		} else {
+			if ((id[i] & 0x0ff) == (id[0] & 0x0ff))
+				denali->total_used_banks++;
+			else
+				break;
+		}
+	}
+}
+
+/*
+ * Use the configuration feature register to determine the maximum number of
+ * banks that the hardware supports.
+ */
+static void detect_max_banks(struct denali_nand_info *denali)
+{
+	uint32_t features = readl(denali->flash_reg + FEATURES);
+	denali->max_banks = 2 << (features & FEATURES__N_BANKS);
+}
+
+static void detect_partition_feature(struct denali_nand_info *denali)
+{
+	/*
+	 * For MRST platform, denali->fwblks represent the
+	 * number of blocks firmware is taken,
+	 * FW is in protect partition and MTD driver has no
+	 * permission to access it. So let driver know how many
+	 * blocks it can't touch.
+	 */
+	if (readl(denali->flash_reg + FEATURES) & FEATURES__PARTITION) {
+		if ((readl(denali->flash_reg + PERM_SRC_ID(1)) &
+			PERM_SRC_ID__SRCID) == SPECTRA_PARTITION_ID) {
+			denali->fwblks =
+			    ((readl(denali->flash_reg + MIN_MAX_BANK(1)) &
+			      MIN_MAX_BANK__MIN_VALUE) *
+			     denali->blksperchip)
+			    +
+			    (readl(denali->flash_reg + MIN_BLK_ADDR(1)) &
+			    MIN_BLK_ADDR__VALUE);
+		} else {
+			denali->fwblks = SPECTRA_START_BLOCK;
+		}
+	} else {
+		denali->fwblks = SPECTRA_START_BLOCK;
+	}
+}
+
+static uint32_t denali_nand_timing_set(struct denali_nand_info *denali)
+{
+	uint32_t id_bytes[5], addr;
+	uint8_t i, maf_id, device_id;
+
+	/* Use read id method to get device ID and other
+	 * params. For some NAND chips, controller can't
+	 * report the correct device ID by reading from
+	 * DEVICE_ID register
+	 * */
+	addr = (uint32_t)MODE_11 | BANK(denali->flash_bank);
+	index_addr(denali, (uint32_t)addr | 0, 0x90);
+	index_addr(denali, (uint32_t)addr | 1, 0);
+	for (i = 0; i < 5; i++)
+		index_addr_read_data(denali, addr | 2, &id_bytes[i]);
+	maf_id = id_bytes[0];
+	device_id = id_bytes[1];
+
+	if (readl(denali->flash_reg + ONFI_DEVICE_NO_OF_LUNS) &
+		ONFI_DEVICE_NO_OF_LUNS__ONFI_DEVICE) { /* ONFI 1.0 NAND */
+		if (get_onfi_nand_para(denali))
+			return -EIO;
+	} else if (maf_id == 0xEC) { /* Samsung NAND */
+		get_samsung_nand_para(denali, device_id);
+	} else if (maf_id == 0x98) { /* Toshiba NAND */
+		get_toshiba_nand_para(denali);
+	} else if (maf_id == 0xAD) { /* Hynix NAND */
+		get_hynix_nand_para(denali, device_id);
+	}
+
+	find_valid_banks(denali);
+
+	detect_partition_feature(denali);
+
+	/* If the user specified to override the default timings
+	 * with a specific ONFI mode, we apply those changes here.
+	 */
+	if (onfi_timing_mode != NAND_DEFAULT_TIMINGS)
+		nand_onfi_timing_set(denali, onfi_timing_mode);
+
+	return 0;
+}
+
+/* validation function to verify that the controlling software is making
+ * a valid request
+ */
+static inline bool is_flash_bank_valid(int flash_bank)
+{
+	return flash_bank >= 0 && flash_bank < 4;
+}
+
+static void denali_irq_init(struct denali_nand_info *denali)
+{
+	uint32_t int_mask = 0;
+	int i;
+
+	/* Disable global interrupts */
+	writel(0, denali->flash_reg + GLOBAL_INT_ENABLE);
+
+	int_mask = DENALI_IRQ_ALL;
+
+	/* Clear all status bits */
+	for (i = 0; i < denali->max_banks; ++i)
+		writel(0xFFFF, denali->flash_reg + INTR_STATUS(i));
+
+	denali_irq_enable(denali, int_mask);
+}
+
+/* This helper function setups the registers for ECC and whether or not
+ * the spare area will be transferred. */
+static void setup_ecc_for_xfer(struct denali_nand_info *denali, bool ecc_en,
+				bool transfer_spare)
+{
+	int ecc_en_flag = 0, transfer_spare_flag = 0;
+
+	/* set ECC, transfer spare bits if needed */
+	ecc_en_flag = ecc_en ? ECC_ENABLE__FLAG : 0;
+	transfer_spare_flag = transfer_spare ? TRANSFER_SPARE_REG__FLAG : 0;
+
+	/* Enable spare area/ECC per user's request. */
+	writel(ecc_en_flag, denali->flash_reg + ECC_ENABLE);
+	/* applicable for MAP01 only */
+	writel(transfer_spare_flag, denali->flash_reg + TRANSFER_SPARE_REG);
+}
+
+/* sends a pipeline command operation to the controller. See the Denali NAND
+ * controller's user guide for more information (section 4.2.3.6).
+ */
+static int denali_send_pipeline_cmd(struct denali_nand_info *denali,
+					bool ecc_en, bool transfer_spare,
+					int access_type, int op)
+{
+	uint32_t addr, cmd, irq_status;
+	static uint32_t page_count = 1;
+
+	setup_ecc_for_xfer(denali, ecc_en, transfer_spare);
+
+	/* clear interrupts */
+	clear_interrupts(denali);
+
+	addr = BANK(denali->flash_bank) | denali->page;
+
+	/* setup the acccess type */
+	cmd = MODE_10 | addr;
+	index_addr(denali, cmd, access_type);
+
+	/* setup the pipeline command */
+	index_addr(denali, cmd, 0x2000 | op | page_count);
+
+	cmd = MODE_01 | addr;
+	writel(cmd, denali->flash_mem + INDEX_CTRL_REG);
+
+	if (op == DENALI_READ) {
+		/* wait for command to be accepted */
+		irq_status = wait_for_irq(denali, INTR_STATUS__LOAD_COMP);
+
+		if (irq_status == 0)
+			return -EIO;
+	}
+
+	return 0;
+}
+
+/* helper function that simply writes a buffer to the flash */
+static int write_data_to_flash_mem(struct denali_nand_info *denali,
+						const uint8_t *buf, int len)
+{
+	uint32_t i = 0, *buf32;
+
+	/* verify that the len is a multiple of 4. see comment in
+	 * read_data_from_flash_mem() */
+	BUG_ON((len % 4) != 0);
+
+	/* write the data to the flash memory */
+	buf32 = (uint32_t *)buf;
+	for (i = 0; i < len / 4; i++)
+		writel(*buf32++, denali->flash_mem + INDEX_DATA_REG);
+	return i * 4; /* intent is to return the number of bytes read */
+}
+
+/* helper function that simply reads a buffer from the flash */
+static int read_data_from_flash_mem(struct denali_nand_info *denali,
+						uint8_t *buf, int len)
+{
+	uint32_t i, *buf32;
+
+	/*
+	 * we assume that len will be a multiple of 4, if not
+	 * it would be nice to know about it ASAP rather than
+	 * have random failures...
+	 * This assumption is based on the fact that this
+	 * function is designed to be used to read flash pages,
+	 * which are typically multiples of 4...
+	 */
+
+	BUG_ON((len % 4) != 0);
+
+	/* transfer the data from the flash */
+	buf32 = (uint32_t *)buf;
+	for (i = 0; i < len / 4; i++)
+		*buf32++ = readl(denali->flash_mem + INDEX_DATA_REG);
+
+	return i * 4; /* intent is to return the number of bytes read */
+}
+
+static void denali_mode_main_access(struct denali_nand_info *denali)
+{
+	uint32_t addr, cmd;
+
+	addr = BANK(denali->flash_bank) | denali->page;
+	cmd = MODE_10 | addr;
+	index_addr(denali, cmd, MAIN_ACCESS);
+}
+
+static void denali_mode_main_spare_access(struct denali_nand_info *denali)
+{
+	uint32_t addr, cmd;
+
+	addr = BANK(denali->flash_bank) | denali->page;
+	cmd = MODE_10 | addr;
+	index_addr(denali, cmd, MAIN_SPARE_ACCESS);
+}
+
+/* writes OOB data to the device */
+static int write_oob_data(struct mtd_info *mtd, uint8_t *buf, int page)
+{
+	struct denali_nand_info *denali = mtd_to_denali(mtd);
+	uint32_t irq_status;
+	uint32_t irq_mask = INTR_STATUS__PROGRAM_COMP |
+						INTR_STATUS__PROGRAM_FAIL;
+	int status = 0;
+
+	denali->page = page;
+
+	if (denali_send_pipeline_cmd(denali, false, true, SPARE_ACCESS,
+				     DENALI_WRITE) == 0) {
+		write_data_to_flash_mem(denali, buf, mtd->oobsize);
+
+		/* wait for operation to complete */
+		irq_status = wait_for_irq(denali, irq_mask);
+
+		if (irq_status == 0) {
+			dev_err(denali->dev, "OOB write failed\n");
+			status = -EIO;
+		}
+	} else {
+		printf("unable to send pipeline command\n");
+		status = -EIO;
+	}
+	return status;
+}
+
+/* reads OOB data from the device */
+static void read_oob_data(struct mtd_info *mtd, uint8_t *buf, int page)
+{
+	struct denali_nand_info *denali = mtd_to_denali(mtd);
+	uint32_t irq_mask = INTR_STATUS__LOAD_COMP,
+			 irq_status = 0, addr = 0x0, cmd = 0x0;
+
+	denali->page = page;
+
+	if (denali_send_pipeline_cmd(denali, false, true, SPARE_ACCESS,
+				     DENALI_READ) == 0) {
+		read_data_from_flash_mem(denali, buf, mtd->oobsize);
+
+		/* wait for command to be accepted
+		 * can always use status0 bit as the mask is identical for each
+		 * bank. */
+		irq_status = wait_for_irq(denali, irq_mask);
+
+		if (irq_status == 0)
+			printf("page on OOB timeout %d\n", denali->page);
+
+		/* We set the device back to MAIN_ACCESS here as I observed
+		 * instability with the controller if you do a block erase
+		 * and the last transaction was a SPARE_ACCESS. Block erase
+		 * is reliable (according to the MTD test infrastructure)
+		 * if you are in MAIN_ACCESS.
+		 */
+		addr = BANK(denali->flash_bank) | denali->page;
+		cmd = MODE_10 | addr;
+		index_addr(denali, cmd, MAIN_ACCESS);
+	}
+}
+
+/* this function examines buffers to see if they contain data that
+ * indicate that the buffer is part of an erased region of flash.
+ */
+static bool is_erased(uint8_t *buf, int len)
+{
+	int i = 0;
+	for (i = 0; i < len; i++)
+		if (buf[i] != 0xFF)
+			return false;
+	return true;
+}
+
+/* programs the controller to either enable/disable DMA transfers */
+static void denali_enable_dma(struct denali_nand_info *denali, bool en)
+{
+	uint32_t reg_val = 0x0;
+
+	if (en)
+		reg_val = DMA_ENABLE__FLAG;
+
+	writel(reg_val, denali->flash_reg + DMA_ENABLE);
+	readl(denali->flash_reg + DMA_ENABLE);
+}
+
+/* setups the HW to perform the data DMA */
+static void denali_setup_dma(struct denali_nand_info *denali, int op)
+{
+	uint32_t mode;
+	const int page_count = 1;
+	uint32_t addr = (uint32_t)denali->buf.dma_buf;
+
+	flush_dcache_range(addr, addr + sizeof(denali->buf.dma_buf));
+
+/* For Denali controller that is 64 bit bus IP core */
+#ifdef CONFIG_SYS_NAND_DENALI_64BIT
+	mode = MODE_10 | BANK(denali->flash_bank) | denali->page;
+
+	/* DMA is a three step process */
+
+	/* 1. setup transfer type, interrupt when complete,
+	      burst len = 64 bytes, the number of pages */
+	index_addr(denali, mode, 0x01002000 | (64 << 16) | op | page_count);
+
+	/* 2. set memory low address bits 31:0 */
+	index_addr(denali, mode, addr);
+
+	/* 3. set memory high address bits 64:32 */
+	index_addr(denali, mode, 0);
+#else
+	mode = MODE_10 | BANK(denali->flash_bank);
+
+	/* DMA is a four step process */
+
+	/* 1. setup transfer type and # of pages */
+	index_addr(denali, mode | denali->page, 0x2000 | op | page_count);
+
+	/* 2. set memory high address bits 23:8 */
+	index_addr(denali, mode | ((uint32_t)(addr >> 16) << 8), 0x2200);
+
+	/* 3. set memory low address bits 23:8 */
+	index_addr(denali, mode | ((uint32_t)addr << 8), 0x2300);
+
+	/* 4.  interrupt when complete, burst len = 64 bytes*/
+	index_addr(denali, mode | 0x14000, 0x2400);
+#endif
+}
+
+/* Common DMA function */
+static uint32_t denali_dma_configuration(struct denali_nand_info *denali,
+					 uint32_t ops, bool raw_xfer,
+					 uint32_t irq_mask, int oob_required)
+{
+	uint32_t irq_status = 0;
+	/* setup_ecc_for_xfer(bool ecc_en, bool transfer_spare) */
+	setup_ecc_for_xfer(denali, !raw_xfer, oob_required);
+
+	/* clear any previous interrupt flags */
+	clear_interrupts(denali);
+
+	/* enable the DMA */
+	denali_enable_dma(denali, true);
+
+	/* setup the DMA */
+	denali_setup_dma(denali, ops);
+
+	/* wait for operation to complete */
+	irq_status = wait_for_irq(denali, irq_mask);
+
+	/* if ECC fault happen, seems we need delay before turning off DMA.
+	 * If not, the controller will go into non responsive condition */
+	if (irq_status & INTR_STATUS__ECC_UNCOR_ERR)
+		udelay(100);
+
+	/* disable the DMA */
+	denali_enable_dma(denali, false);
+
+	return irq_status;
+}
+
+static int write_page(struct mtd_info *mtd, struct nand_chip *chip,
+			const uint8_t *buf, bool raw_xfer, int oob_required)
+{
+	struct denali_nand_info *denali = mtd_to_denali(mtd);
+
+	uint32_t irq_status = 0;
+	uint32_t irq_mask = INTR_STATUS__DMA_CMD_COMP;
+
+	denali->status = 0;
+
+	/* copy buffer into DMA buffer */
+	memcpy(denali->buf.dma_buf, buf, mtd->writesize);
+
+	/* need extra memcpy for raw transfer */
+	if (raw_xfer)
+		memcpy(denali->buf.dma_buf + mtd->writesize,
+		       chip->oob_poi, mtd->oobsize);
+
+	/* setting up DMA */
+	irq_status = denali_dma_configuration(denali, DENALI_WRITE, raw_xfer,
+					      irq_mask, oob_required);
+
+	/* if timeout happen, error out */
+	if (!(irq_status & INTR_STATUS__DMA_CMD_COMP)) {
+		debug("DMA timeout for denali write_page\n");
+		denali->status = NAND_STATUS_FAIL;
+		return -EIO;
+	}
+
+	if (irq_status & INTR_STATUS__LOCKED_BLK) {
+		debug("Failed as write to locked block\n");
+		denali->status = NAND_STATUS_FAIL;
+		return -EIO;
+	}
+	return 0;
+}
+
+/* NAND core entry points */
+
+/*
+ * this is the callback that the NAND core calls to write a page. Since
+ * writing a page with ECC or without is similar, all the work is done
+ * by write_page above.
+ */
+static int denali_write_page(struct mtd_info *mtd, struct nand_chip *chip,
+				const uint8_t *buf, int oob_required)
+{
+	struct denali_nand_info *denali = mtd_to_denali(mtd);
+
+	/*
+	 * for regular page writes, we let HW handle all the ECC
+	 * data written to the device.
+	 */
+	if (oob_required)
+		/* switch to main + spare access */
+		denali_mode_main_spare_access(denali);
+	else
+		/* switch to main access only */
+		denali_mode_main_access(denali);
+
+	return write_page(mtd, chip, buf, false, oob_required);
+}
+
+/*
+ * This is the callback that the NAND core calls to write a page without ECC.
+ * raw access is similar to ECC page writes, so all the work is done in the
+ * write_page() function above.
+ */
+static int denali_write_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
+					const uint8_t *buf, int oob_required)
+{
+	struct denali_nand_info *denali = mtd_to_denali(mtd);
+
+	/*
+	 * for raw page writes, we want to disable ECC and simply write
+	 * whatever data is in the buffer.
+	 */
+
+	if (oob_required)
+		/* switch to main + spare access */
+		denali_mode_main_spare_access(denali);
+	else
+		/* switch to main access only */
+		denali_mode_main_access(denali);
+
+	return write_page(mtd, chip, buf, true, oob_required);
+}
+
+static int denali_write_oob(struct mtd_info *mtd, struct nand_chip *chip,
+				int page)
+{
+	return write_oob_data(mtd, chip->oob_poi, page);
+}
+
+/* raw include ECC value and all the spare area */
+static int denali_read_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
+				uint8_t *buf, int oob_required, int page)
+{
+	struct denali_nand_info *denali = mtd_to_denali(mtd);
+
+	uint32_t irq_status, irq_mask = INTR_STATUS__DMA_CMD_COMP;
+
+	if (denali->page != page) {
+		debug("Missing NAND_CMD_READ0 command\n");
+		return -EIO;
+	}
+
+	if (oob_required)
+		/* switch to main + spare access */
+		denali_mode_main_spare_access(denali);
+	else
+		/* switch to main access only */
+		denali_mode_main_access(denali);
+
+	/* setting up the DMA where ecc_enable is false */
+	irq_status = denali_dma_configuration(denali, DENALI_READ, true,
+					      irq_mask, oob_required);
+
+	/* if timeout happen, error out */
+	if (!(irq_status & INTR_STATUS__DMA_CMD_COMP)) {
+		debug("DMA timeout for denali_read_page_raw\n");
+		return -EIO;
+	}
+
+	/* splitting the content to destination buffer holder */
+	memcpy(chip->oob_poi, (denali->buf.dma_buf + mtd->writesize),
+	       mtd->oobsize);
+	memcpy(buf, denali->buf.dma_buf, mtd->writesize);
+
+	return 0;
+}
+
+static int denali_read_page(struct mtd_info *mtd, struct nand_chip *chip,
+				uint8_t *buf, int oob_required, int page)
+{
+	struct denali_nand_info *denali = mtd_to_denali(mtd);
+	uint32_t irq_status, irq_mask =	INTR_STATUS__DMA_CMD_COMP;
+
+	if (denali->page != page) {
+		debug("Missing NAND_CMD_READ0 command\n");
+		return -EIO;
+	}
+
+	if (oob_required)
+		/* switch to main + spare access */
+		denali_mode_main_spare_access(denali);
+	else
+		/* switch to main access only */
+		denali_mode_main_access(denali);
+
+	/* setting up the DMA where ecc_enable is true */
+	irq_status = denali_dma_configuration(denali, DENALI_READ, false,
+					      irq_mask, oob_required);
+
+	memcpy(buf, denali->buf.dma_buf, mtd->writesize);
+
+	/* check whether any ECC error */
+	if (irq_status & INTR_STATUS__ECC_UNCOR_ERR) {
+		/* is the ECC cause by erase page, check using read_page_raw */
+		debug("  Uncorrected ECC detected\n");
+		denali_read_page_raw(mtd, chip, buf, oob_required,
+				     denali->page);
+
+		if (is_erased(buf, mtd->writesize) == true &&
+		    is_erased(chip->oob_poi, mtd->oobsize) == true) {
+			debug("  ECC error cause by erased block\n");
+			/* false alarm, return the 0xFF */
+		} else {
+			return -EIO;
+		}
+	}
+	memcpy(buf, denali->buf.dma_buf, mtd->writesize);
+	return 0;
+}
+
+static int denali_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
+				int page)
+{
+	read_oob_data(mtd, chip->oob_poi, page);
+
+	return 0;
+}
+
+static uint8_t denali_read_byte(struct mtd_info *mtd)
+{
+	struct denali_nand_info *denali = mtd_to_denali(mtd);
+	uint32_t addr, result;
+
+	addr = (uint32_t)MODE_11 | BANK(denali->flash_bank);
+	index_addr_read_data(denali, addr | 2, &result);
+	return (uint8_t)result & 0xFF;
+}
+
+static void denali_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
+{
+	struct denali_nand_info *denali = mtd_to_denali(mtd);
+	uint32_t i, addr, result;
+
+	/* delay for tR (data transfer from Flash array to data register) */
+	udelay(25);
+
+	/* ensure device completed else additional delay and polling */
+	wait_for_irq(denali, INTR_STATUS__INT_ACT);
+
+	addr = (uint32_t)MODE_11 | BANK(denali->flash_bank);
+	for (i = 0; i < len; i++) {
+		index_addr_read_data(denali, (uint32_t)addr | 2, &result);
+		write_byte_to_buf(denali, result);
+	}
+	memcpy(buf, denali->buf.buf, len);
+}
+
+static void denali_select_chip(struct mtd_info *mtd, int chip)
+{
+	struct denali_nand_info *denali = mtd_to_denali(mtd);
+
+	denali->flash_bank = chip;
+}
+
+static int denali_waitfunc(struct mtd_info *mtd, struct nand_chip *chip)
+{
+	struct denali_nand_info *denali = mtd_to_denali(mtd);
+	int status = denali->status;
+	denali->status = 0;
+
+	return status;
+}
+
+static void denali_erase(struct mtd_info *mtd, int page)
+{
+	struct denali_nand_info *denali = mtd_to_denali(mtd);
+	uint32_t cmd, irq_status;
+
+	/* clear interrupts */
+	clear_interrupts(denali);
+
+	/* setup page read request for access type */
+	cmd = MODE_10 | BANK(denali->flash_bank) | page;
+	index_addr(denali, cmd, 0x1);
+
+	/* wait for erase to complete or failure to occur */
+	irq_status = wait_for_irq(denali, INTR_STATUS__ERASE_COMP |
+					INTR_STATUS__ERASE_FAIL);
+
+	if (irq_status & INTR_STATUS__ERASE_FAIL ||
+	    irq_status & INTR_STATUS__LOCKED_BLK)
+		denali->status = NAND_STATUS_FAIL;
+	else
+		denali->status = 0;
+}
+
+static void denali_cmdfunc(struct mtd_info *mtd, unsigned int cmd, int col,
+			   int page)
+{
+	struct denali_nand_info *denali = mtd_to_denali(mtd);
+	uint32_t addr;
+
+	switch (cmd) {
+	case NAND_CMD_PAGEPROG:
+		break;
+	case NAND_CMD_STATUS:
+		addr = MODE_11 | BANK(denali->flash_bank);
+		index_addr(denali, addr | 0, cmd);
+		break;
+	case NAND_CMD_PARAM:
+		clear_interrupts(denali);
+	case NAND_CMD_READID:
+		reset_buf(denali);
+		/* sometimes ManufactureId read from register is not right
+		 * e.g. some of Micron MT29F32G08QAA MLC NAND chips
+		 * So here we send READID cmd to NAND insteand
+		 * */
+		addr = MODE_11 | BANK(denali->flash_bank);
+		index_addr(denali, addr | 0, cmd);
+		index_addr(denali, addr | 1, col & 0xFF);
+		break;
+	case NAND_CMD_READ0:
+	case NAND_CMD_SEQIN:
+		denali->page = page;
+		break;
+	case NAND_CMD_RESET:
+		reset_bank(denali);
+		break;
+	case NAND_CMD_READOOB:
+		/* TODO: Read OOB data */
+		break;
+	case NAND_CMD_ERASE1:
+		/*
+		 * supporting block erase only, not multiblock erase as
+		 * it will cross plane and software need complex calculation
+		 * to identify the block count for the cross plane
+		 */
+		denali_erase(mtd, page);
+		break;
+	case NAND_CMD_ERASE2:
+		/* nothing to do here as it was done during NAND_CMD_ERASE1 */
+		break;
+	case NAND_CMD_UNLOCK1:
+		addr = MODE_10 | BANK(denali->flash_bank) | page;
+		index_addr(denali, addr | 0, DENALI_UNLOCK_START);
+		break;
+	case NAND_CMD_UNLOCK2:
+		addr = MODE_10 | BANK(denali->flash_bank) | page;
+		index_addr(denali, addr | 0, DENALI_UNLOCK_END);
+		break;
+	case NAND_CMD_LOCK:
+		addr = MODE_10 | BANK(denali->flash_bank);
+		index_addr(denali, addr | 0, DENALI_LOCK);
+		break;
+	default:
+		printf(": unsupported command received 0x%x\n", cmd);
+		break;
+	}
+}
+/* end NAND core entry points */
+
+/* Initialization code to bring the device up to a known good state */
+static void denali_hw_init(struct denali_nand_info *denali)
+{
+	/*
+	 * tell driver how many bit controller will skip before writing
+	 * ECC code in OOB. This is normally used for bad block marker
+	 */
+	writel(CONFIG_NAND_DENALI_SPARE_AREA_SKIP_BYTES,
+	       denali->flash_reg + SPARE_AREA_SKIP_BYTES);
+	detect_max_banks(denali);
+	denali_nand_reset(denali);
+	writel(0x0F, denali->flash_reg + RB_PIN_ENABLED);
+	writel(CHIP_EN_DONT_CARE__FLAG,
+	       denali->flash_reg + CHIP_ENABLE_DONT_CARE);
+	writel(0xffff, denali->flash_reg + SPARE_AREA_MARKER);
+
+	/* Should set value for these registers when init */
+	writel(0, denali->flash_reg + TWO_ROW_ADDR_CYCLES);
+	writel(1, denali->flash_reg + ECC_ENABLE);
+	denali_nand_timing_set(denali);
+	denali_irq_init(denali);
+}
+
+static struct nand_ecclayout nand_oob;
+
+static int denali_nand_init(struct nand_chip *nand)
+{
+	struct denali_nand_info *denali;
+
+	denali = malloc(sizeof(*denali));
+	if (!denali)
+		return -ENOMEM;
+
+	nand->priv = denali;
+
+	denali->flash_reg = (void  __iomem *)CONFIG_SYS_NAND_REGS_BASE;
+	denali->flash_mem = (void  __iomem *)CONFIG_SYS_NAND_DATA_BASE;
+
+#ifdef CONFIG_SYS_NAND_USE_FLASH_BBT
+	/* check whether flash got BBT table (located at end of flash). As we
+	 * use NAND_BBT_NO_OOB, the BBT page will start with
+	 * bbt_pattern. We will have mirror pattern too */
+	nand->bbt_options |= NAND_BBT_USE_FLASH;
+	/*
+	 * We are using main + spare with ECC support. As BBT need ECC support,
+	 * we need to ensure BBT code don't write to OOB for the BBT pattern.
+	 * All BBT info will be stored into data area with ECC support.
+	 */
+	nand->bbt_options |= NAND_BBT_NO_OOB;
+#endif
+
+	nand->ecc.mode = NAND_ECC_HW;
+	nand->ecc.size = CONFIG_NAND_DENALI_ECC_SIZE;
+	nand->ecc.read_oob = denali_read_oob;
+	nand->ecc.write_oob = denali_write_oob;
+	nand->ecc.read_page = denali_read_page;
+	nand->ecc.read_page_raw = denali_read_page_raw;
+	nand->ecc.write_page = denali_write_page;
+	nand->ecc.write_page_raw = denali_write_page_raw;
+	/*
+	 * Tell driver the ecc strength. This register may be already set
+	 * correctly. So we read this value out.
+	 */
+	nand->ecc.strength = readl(denali->flash_reg + ECC_CORRECTION);
+	switch (nand->ecc.size) {
+	case 512:
+		nand->ecc.bytes = (nand->ecc.strength * 13 + 15) / 16 * 2;
+		break;
+	case 1024:
+		nand->ecc.bytes = (nand->ecc.strength * 14 + 15) / 16 * 2;
+		break;
+	default:
+		pr_err("Unsupported ECC size\n");
+		return -EINVAL;
+	}
+	nand_oob.eccbytes = nand->ecc.bytes;
+	nand->ecc.layout = &nand_oob;
+
+	/* Set address of hardware control function */
+	nand->cmdfunc = denali_cmdfunc;
+	nand->read_byte = denali_read_byte;
+	nand->read_buf = denali_read_buf;
+	nand->select_chip = denali_select_chip;
+	nand->waitfunc = denali_waitfunc;
+	denali_hw_init(denali);
+	return 0;
+}
+
+int board_nand_init(struct nand_chip *chip)
+{
+	return denali_nand_init(chip);
+}