Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2316 insertions, 0 deletions

diff --git a/drivers/mtd/nand/raw/omap2.c b/drivers/mtd/nand/raw/omap2.c
new file mode 100644
index 000000000..7a4af5f3e
--- /dev/null
+++ b/drivers/mtd/nand/raw/omap2.c
@@ -0,0 +1,2316 @@
+/*
+ * Copyright © 2004 Texas Instruments, Jian Zhang <jzhang@ti.com>
+ * Copyright © 2004 Micron Technology Inc.
+ * Copyright © 2004 David Brownell
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/sched.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/rawnand.h>
+#include <linux/mtd/partitions.h>
+#include <linux/omap-dma.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+#include <linux/mtd/nand_bch.h>
+#include <linux/platform_data/elm.h>
+
+#include <linux/omap-gpmc.h>
+#include <linux/platform_data/mtd-nand-omap2.h>
+
+#define	DRIVER_NAME	"omap2-nand"
+#define	OMAP_NAND_TIMEOUT_MS	5000
+
+#define NAND_Ecc_P1e		(1 << 0)
+#define NAND_Ecc_P2e		(1 << 1)
+#define NAND_Ecc_P4e		(1 << 2)
+#define NAND_Ecc_P8e		(1 << 3)
+#define NAND_Ecc_P16e		(1 << 4)
+#define NAND_Ecc_P32e		(1 << 5)
+#define NAND_Ecc_P64e		(1 << 6)
+#define NAND_Ecc_P128e		(1 << 7)
+#define NAND_Ecc_P256e		(1 << 8)
+#define NAND_Ecc_P512e		(1 << 9)
+#define NAND_Ecc_P1024e		(1 << 10)
+#define NAND_Ecc_P2048e		(1 << 11)
+
+#define NAND_Ecc_P1o		(1 << 16)
+#define NAND_Ecc_P2o		(1 << 17)
+#define NAND_Ecc_P4o		(1 << 18)
+#define NAND_Ecc_P8o		(1 << 19)
+#define NAND_Ecc_P16o		(1 << 20)
+#define NAND_Ecc_P32o		(1 << 21)
+#define NAND_Ecc_P64o		(1 << 22)
+#define NAND_Ecc_P128o		(1 << 23)
+#define NAND_Ecc_P256o		(1 << 24)
+#define NAND_Ecc_P512o		(1 << 25)
+#define NAND_Ecc_P1024o		(1 << 26)
+#define NAND_Ecc_P2048o		(1 << 27)
+
+#define TF(value)	(value ? 1 : 0)
+
+#define P2048e(a)	(TF(a & NAND_Ecc_P2048e)	<< 0)
+#define P2048o(a)	(TF(a & NAND_Ecc_P2048o)	<< 1)
+#define P1e(a)		(TF(a & NAND_Ecc_P1e)		<< 2)
+#define P1o(a)		(TF(a & NAND_Ecc_P1o)		<< 3)
+#define P2e(a)		(TF(a & NAND_Ecc_P2e)		<< 4)
+#define P2o(a)		(TF(a & NAND_Ecc_P2o)		<< 5)
+#define P4e(a)		(TF(a & NAND_Ecc_P4e)		<< 6)
+#define P4o(a)		(TF(a & NAND_Ecc_P4o)		<< 7)
+
+#define P8e(a)		(TF(a & NAND_Ecc_P8e)		<< 0)
+#define P8o(a)		(TF(a & NAND_Ecc_P8o)		<< 1)
+#define P16e(a)		(TF(a & NAND_Ecc_P16e)		<< 2)
+#define P16o(a)		(TF(a & NAND_Ecc_P16o)		<< 3)
+#define P32e(a)		(TF(a & NAND_Ecc_P32e)		<< 4)
+#define P32o(a)		(TF(a & NAND_Ecc_P32o)		<< 5)
+#define P64e(a)		(TF(a & NAND_Ecc_P64e)		<< 6)
+#define P64o(a)		(TF(a & NAND_Ecc_P64o)		<< 7)
+
+#define P128e(a)	(TF(a & NAND_Ecc_P128e)		<< 0)
+#define P128o(a)	(TF(a & NAND_Ecc_P128o)		<< 1)
+#define P256e(a)	(TF(a & NAND_Ecc_P256e)		<< 2)
+#define P256o(a)	(TF(a & NAND_Ecc_P256o)		<< 3)
+#define P512e(a)	(TF(a & NAND_Ecc_P512e)		<< 4)
+#define P512o(a)	(TF(a & NAND_Ecc_P512o)		<< 5)
+#define P1024e(a)	(TF(a & NAND_Ecc_P1024e)	<< 6)
+#define P1024o(a)	(TF(a & NAND_Ecc_P1024o)	<< 7)
+
+#define P8e_s(a)	(TF(a & NAND_Ecc_P8e)		<< 0)
+#define P8o_s(a)	(TF(a & NAND_Ecc_P8o)		<< 1)
+#define P16e_s(a)	(TF(a & NAND_Ecc_P16e)		<< 2)
+#define P16o_s(a)	(TF(a & NAND_Ecc_P16o)		<< 3)
+#define P1e_s(a)	(TF(a & NAND_Ecc_P1e)		<< 4)
+#define P1o_s(a)	(TF(a & NAND_Ecc_P1o)		<< 5)
+#define P2e_s(a)	(TF(a & NAND_Ecc_P2e)		<< 6)
+#define P2o_s(a)	(TF(a & NAND_Ecc_P2o)		<< 7)
+
+#define P4e_s(a)	(TF(a & NAND_Ecc_P4e)		<< 0)
+#define P4o_s(a)	(TF(a & NAND_Ecc_P4o)		<< 1)
+
+#define	PREFETCH_CONFIG1_CS_SHIFT	24
+#define	ECC_CONFIG_CS_SHIFT		1
+#define	CS_MASK				0x7
+#define	ENABLE_PREFETCH			(0x1 << 7)
+#define	DMA_MPU_MODE_SHIFT		2
+#define	ECCSIZE0_SHIFT			12
+#define	ECCSIZE1_SHIFT			22
+#define	ECC1RESULTSIZE			0x1
+#define	ECCCLEAR			0x100
+#define	ECC1				0x1
+#define	PREFETCH_FIFOTHRESHOLD_MAX	0x40
+#define	PREFETCH_FIFOTHRESHOLD(val)	((val) << 8)
+#define	PREFETCH_STATUS_COUNT(val)	(val & 0x00003fff)
+#define	PREFETCH_STATUS_FIFO_CNT(val)	((val >> 24) & 0x7F)
+#define	STATUS_BUFF_EMPTY		0x00000001
+
+#define SECTOR_BYTES		512
+/* 4 bit padding to make byte aligned, 56 = 52 + 4 */
+#define BCH4_BIT_PAD		4
+
+/* GPMC ecc engine settings for read */
+#define BCH_WRAPMODE_1		1	/* BCH wrap mode 1 */
+#define BCH8R_ECC_SIZE0		0x1a	/* ecc_size0 = 26 */
+#define BCH8R_ECC_SIZE1		0x2	/* ecc_size1 = 2 */
+#define BCH4R_ECC_SIZE0		0xd	/* ecc_size0 = 13 */
+#define BCH4R_ECC_SIZE1		0x3	/* ecc_size1 = 3 */
+
+/* GPMC ecc engine settings for write */
+#define BCH_WRAPMODE_6		6	/* BCH wrap mode 6 */
+#define BCH_ECC_SIZE0		0x0	/* ecc_size0 = 0, no oob protection */
+#define BCH_ECC_SIZE1		0x20	/* ecc_size1 = 32 */
+
+#define BADBLOCK_MARKER_LENGTH		2
+
+static u_char bch16_vector[] = {0xf5, 0x24, 0x1c, 0xd0, 0x61, 0xb3, 0xf1, 0x55,
+				0x2e, 0x2c, 0x86, 0xa3, 0xed, 0x36, 0x1b, 0x78,
+				0x48, 0x76, 0xa9, 0x3b, 0x97, 0xd1, 0x7a, 0x93,
+				0x07, 0x0e};
+static u_char bch8_vector[] = {0xf3, 0xdb, 0x14, 0x16, 0x8b, 0xd2, 0xbe, 0xcc,
+	0xac, 0x6b, 0xff, 0x99, 0x7b};
+static u_char bch4_vector[] = {0x00, 0x6b, 0x31, 0xdd, 0x41, 0xbc, 0x10};
+
+struct omap_nand_info {
+	struct nand_chip		nand;
+	struct platform_device		*pdev;
+
+	int				gpmc_cs;
+	bool				dev_ready;
+	enum nand_io			xfer_type;
+	int				devsize;
+	enum omap_ecc			ecc_opt;
+	struct device_node		*elm_of_node;
+
+	unsigned long			phys_base;
+	struct completion		comp;
+	struct dma_chan			*dma;
+	int				gpmc_irq_fifo;
+	int				gpmc_irq_count;
+	enum {
+		OMAP_NAND_IO_READ = 0,	/* read */
+		OMAP_NAND_IO_WRITE,	/* write */
+	} iomode;
+	u_char				*buf;
+	int					buf_len;
+	/* Interface to GPMC */
+	struct gpmc_nand_regs		reg;
+	struct gpmc_nand_ops		*ops;
+	bool				flash_bbt;
+	/* fields specific for BCHx_HW ECC scheme */
+	struct device			*elm_dev;
+	/* NAND ready gpio */
+	struct gpio_desc		*ready_gpiod;
+};
+
+static inline struct omap_nand_info *mtd_to_omap(struct mtd_info *mtd)
+{
+	return container_of(mtd_to_nand(mtd), struct omap_nand_info, nand);
+}
+
+/**
+ * omap_prefetch_enable - configures and starts prefetch transfer
+ * @cs: cs (chip select) number
+ * @fifo_th: fifo threshold to be used for read/ write
+ * @dma_mode: dma mode enable (1) or disable (0)
+ * @u32_count: number of bytes to be transferred
+ * @is_write: prefetch read(0) or write post(1) mode
+ */
+static int omap_prefetch_enable(int cs, int fifo_th, int dma_mode,
+	unsigned int u32_count, int is_write, struct omap_nand_info *info)
+{
+	u32 val;
+
+	if (fifo_th > PREFETCH_FIFOTHRESHOLD_MAX)
+		return -1;
+
+	if (readl(info->reg.gpmc_prefetch_control))
+		return -EBUSY;
+
+	/* Set the amount of bytes to be prefetched */
+	writel(u32_count, info->reg.gpmc_prefetch_config2);
+
+	/* Set dma/mpu mode, the prefetch read / post write and
+	 * enable the engine. Set which cs is has requested for.
+	 */
+	val = ((cs << PREFETCH_CONFIG1_CS_SHIFT) |
+		PREFETCH_FIFOTHRESHOLD(fifo_th) | ENABLE_PREFETCH |
+		(dma_mode << DMA_MPU_MODE_SHIFT) | (is_write & 0x1));
+	writel(val, info->reg.gpmc_prefetch_config1);
+
+	/*  Start the prefetch engine */
+	writel(0x1, info->reg.gpmc_prefetch_control);
+
+	return 0;
+}
+
+/**
+ * omap_prefetch_reset - disables and stops the prefetch engine
+ */
+static int omap_prefetch_reset(int cs, struct omap_nand_info *info)
+{
+	u32 config1;
+
+	/* check if the same module/cs is trying to reset */
+	config1 = readl(info->reg.gpmc_prefetch_config1);
+	if (((config1 >> PREFETCH_CONFIG1_CS_SHIFT) & CS_MASK) != cs)
+		return -EINVAL;
+
+	/* Stop the PFPW engine */
+	writel(0x0, info->reg.gpmc_prefetch_control);
+
+	/* Reset/disable the PFPW engine */
+	writel(0x0, info->reg.gpmc_prefetch_config1);
+
+	return 0;
+}
+
+/**
+ * omap_hwcontrol - hardware specific access to control-lines
+ * @mtd: MTD device structure
+ * @cmd: command to device
+ * @ctrl:
+ * NAND_NCE: bit 0 -> don't care
+ * NAND_CLE: bit 1 -> Command Latch
+ * NAND_ALE: bit 2 -> Address Latch
+ *
+ * NOTE: boards may use different bits for these!!
+ */
+static void omap_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+
+	if (cmd != NAND_CMD_NONE) {
+		if (ctrl & NAND_CLE)
+			writeb(cmd, info->reg.gpmc_nand_command);
+
+		else if (ctrl & NAND_ALE)
+			writeb(cmd, info->reg.gpmc_nand_address);
+
+		else /* NAND_NCE */
+			writeb(cmd, info->reg.gpmc_nand_data);
+	}
+}
+
+/**
+ * omap_read_buf8 - read data from NAND controller into buffer
+ * @mtd: MTD device structure
+ * @buf: buffer to store date
+ * @len: number of bytes to read
+ */
+static void omap_read_buf8(struct mtd_info *mtd, u_char *buf, int len)
+{
+	struct nand_chip *nand = mtd_to_nand(mtd);
+
+	ioread8_rep(nand->IO_ADDR_R, buf, len);
+}
+
+/**
+ * omap_write_buf8 - write buffer to NAND controller
+ * @mtd: MTD device structure
+ * @buf: data buffer
+ * @len: number of bytes to write
+ */
+static void omap_write_buf8(struct mtd_info *mtd, const u_char *buf, int len)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	u_char *p = (u_char *)buf;
+	bool status;
+
+	while (len--) {
+		iowrite8(*p++, info->nand.IO_ADDR_W);
+		/* wait until buffer is available for write */
+		do {
+			status = info->ops->nand_writebuffer_empty();
+		} while (!status);
+	}
+}
+
+/**
+ * omap_read_buf16 - read data from NAND controller into buffer
+ * @mtd: MTD device structure
+ * @buf: buffer to store date
+ * @len: number of bytes to read
+ */
+static void omap_read_buf16(struct mtd_info *mtd, u_char *buf, int len)
+{
+	struct nand_chip *nand = mtd_to_nand(mtd);
+
+	ioread16_rep(nand->IO_ADDR_R, buf, len / 2);
+}
+
+/**
+ * omap_write_buf16 - write buffer to NAND controller
+ * @mtd: MTD device structure
+ * @buf: data buffer
+ * @len: number of bytes to write
+ */
+static void omap_write_buf16(struct mtd_info *mtd, const u_char * buf, int len)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	u16 *p = (u16 *) buf;
+	bool status;
+	/* FIXME try bursts of writesw() or DMA ... */
+	len >>= 1;
+
+	while (len--) {
+		iowrite16(*p++, info->nand.IO_ADDR_W);
+		/* wait until buffer is available for write */
+		do {
+			status = info->ops->nand_writebuffer_empty();
+		} while (!status);
+	}
+}
+
+/**
+ * omap_read_buf_pref - read data from NAND controller into buffer
+ * @mtd: MTD device structure
+ * @buf: buffer to store date
+ * @len: number of bytes to read
+ */
+static void omap_read_buf_pref(struct mtd_info *mtd, u_char *buf, int len)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	uint32_t r_count = 0;
+	int ret = 0;
+	u32 *p = (u32 *)buf;
+
+	/* take care of subpage reads */
+	if (len % 4) {
+		if (info->nand.options & NAND_BUSWIDTH_16)
+			omap_read_buf16(mtd, buf, len % 4);
+		else
+			omap_read_buf8(mtd, buf, len % 4);
+		p = (u32 *) (buf + len % 4);
+		len -= len % 4;
+	}
+
+	/* configure and start prefetch transfer */
+	ret = omap_prefetch_enable(info->gpmc_cs,
+			PREFETCH_FIFOTHRESHOLD_MAX, 0x0, len, 0x0, info);
+	if (ret) {
+		/* PFPW engine is busy, use cpu copy method */
+		if (info->nand.options & NAND_BUSWIDTH_16)
+			omap_read_buf16(mtd, (u_char *)p, len);
+		else
+			omap_read_buf8(mtd, (u_char *)p, len);
+	} else {
+		do {
+			r_count = readl(info->reg.gpmc_prefetch_status);
+			r_count = PREFETCH_STATUS_FIFO_CNT(r_count);
+			r_count = r_count >> 2;
+			ioread32_rep(info->nand.IO_ADDR_R, p, r_count);
+			p += r_count;
+			len -= r_count << 2;
+		} while (len);
+		/* disable and stop the PFPW engine */
+		omap_prefetch_reset(info->gpmc_cs, info);
+	}
+}
+
+/**
+ * omap_write_buf_pref - write buffer to NAND controller
+ * @mtd: MTD device structure
+ * @buf: data buffer
+ * @len: number of bytes to write
+ */
+static void omap_write_buf_pref(struct mtd_info *mtd,
+					const u_char *buf, int len)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	uint32_t w_count = 0;
+	int i = 0, ret = 0;
+	u16 *p = (u16 *)buf;
+	unsigned long tim, limit;
+	u32 val;
+
+	/* take care of subpage writes */
+	if (len % 2 != 0) {
+		writeb(*buf, info->nand.IO_ADDR_W);
+		p = (u16 *)(buf + 1);
+		len--;
+	}
+
+	/*  configure and start prefetch transfer */
+	ret = omap_prefetch_enable(info->gpmc_cs,
+			PREFETCH_FIFOTHRESHOLD_MAX, 0x0, len, 0x1, info);
+	if (ret) {
+		/* PFPW engine is busy, use cpu copy method */
+		if (info->nand.options & NAND_BUSWIDTH_16)
+			omap_write_buf16(mtd, (u_char *)p, len);
+		else
+			omap_write_buf8(mtd, (u_char *)p, len);
+	} else {
+		while (len) {
+			w_count = readl(info->reg.gpmc_prefetch_status);
+			w_count = PREFETCH_STATUS_FIFO_CNT(w_count);
+			w_count = w_count >> 1;
+			for (i = 0; (i < w_count) && len; i++, len -= 2)
+				iowrite16(*p++, info->nand.IO_ADDR_W);
+		}
+		/* wait for data to flushed-out before reset the prefetch */
+		tim = 0;
+		limit = (loops_per_jiffy *
+					msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
+		do {
+			cpu_relax();
+			val = readl(info->reg.gpmc_prefetch_status);
+			val = PREFETCH_STATUS_COUNT(val);
+		} while (val && (tim++ < limit));
+
+		/* disable and stop the PFPW engine */
+		omap_prefetch_reset(info->gpmc_cs, info);
+	}
+}
+
+/*
+ * omap_nand_dma_callback: callback on the completion of dma transfer
+ * @data: pointer to completion data structure
+ */
+static void omap_nand_dma_callback(void *data)
+{
+	complete((struct completion *) data);
+}
+
+/*
+ * omap_nand_dma_transfer: configure and start dma transfer
+ * @mtd: MTD device structure
+ * @addr: virtual address in RAM of source/destination
+ * @len: number of data bytes to be transferred
+ * @is_write: flag for read/write operation
+ */
+static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
+					unsigned int len, int is_write)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	struct dma_async_tx_descriptor *tx;
+	enum dma_data_direction dir = is_write ? DMA_TO_DEVICE :
+							DMA_FROM_DEVICE;
+	struct scatterlist sg;
+	unsigned long tim, limit;
+	unsigned n;
+	int ret;
+	u32 val;
+
+	if (!virt_addr_valid(addr))
+		goto out_copy;
+
+	sg_init_one(&sg, addr, len);
+	n = dma_map_sg(info->dma->device->dev, &sg, 1, dir);
+	if (n == 0) {
+		dev_err(&info->pdev->dev,
+			"Couldn't DMA map a %d byte buffer\n", len);
+		goto out_copy;
+	}
+
+	tx = dmaengine_prep_slave_sg(info->dma, &sg, n,
+		is_write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
+		DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!tx)
+		goto out_copy_unmap;
+
+	tx->callback = omap_nand_dma_callback;
+	tx->callback_param = &info->comp;
+	dmaengine_submit(tx);
+
+	init_completion(&info->comp);
+
+	/* setup and start DMA using dma_addr */
+	dma_async_issue_pending(info->dma);
+
+	/*  configure and start prefetch transfer */
+	ret = omap_prefetch_enable(info->gpmc_cs,
+		PREFETCH_FIFOTHRESHOLD_MAX, 0x1, len, is_write, info);
+	if (ret)
+		/* PFPW engine is busy, use cpu copy method */
+		goto out_copy_unmap;
+
+	wait_for_completion(&info->comp);
+	tim = 0;
+	limit = (loops_per_jiffy * msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
+
+	do {
+		cpu_relax();
+		val = readl(info->reg.gpmc_prefetch_status);
+		val = PREFETCH_STATUS_COUNT(val);
+	} while (val && (tim++ < limit));
+
+	/* disable and stop the PFPW engine */
+	omap_prefetch_reset(info->gpmc_cs, info);
+
+	dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
+	return 0;
+
+out_copy_unmap:
+	dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
+out_copy:
+	if (info->nand.options & NAND_BUSWIDTH_16)
+		is_write == 0 ? omap_read_buf16(mtd, (u_char *) addr, len)
+			: omap_write_buf16(mtd, (u_char *) addr, len);
+	else
+		is_write == 0 ? omap_read_buf8(mtd, (u_char *) addr, len)
+			: omap_write_buf8(mtd, (u_char *) addr, len);
+	return 0;
+}
+
+/**
+ * omap_read_buf_dma_pref - read data from NAND controller into buffer
+ * @mtd: MTD device structure
+ * @buf: buffer to store date
+ * @len: number of bytes to read
+ */
+static void omap_read_buf_dma_pref(struct mtd_info *mtd, u_char *buf, int len)
+{
+	if (len <= mtd->oobsize)
+		omap_read_buf_pref(mtd, buf, len);
+	else
+		/* start transfer in DMA mode */
+		omap_nand_dma_transfer(mtd, buf, len, 0x0);
+}
+
+/**
+ * omap_write_buf_dma_pref - write buffer to NAND controller
+ * @mtd: MTD device structure
+ * @buf: data buffer
+ * @len: number of bytes to write
+ */
+static void omap_write_buf_dma_pref(struct mtd_info *mtd,
+					const u_char *buf, int len)
+{
+	if (len <= mtd->oobsize)
+		omap_write_buf_pref(mtd, buf, len);
+	else
+		/* start transfer in DMA mode */
+		omap_nand_dma_transfer(mtd, (u_char *) buf, len, 0x1);
+}
+
+/*
+ * omap_nand_irq - GPMC irq handler
+ * @this_irq: gpmc irq number
+ * @dev: omap_nand_info structure pointer is passed here
+ */
+static irqreturn_t omap_nand_irq(int this_irq, void *dev)
+{
+	struct omap_nand_info *info = (struct omap_nand_info *) dev;
+	u32 bytes;
+
+	bytes = readl(info->reg.gpmc_prefetch_status);
+	bytes = PREFETCH_STATUS_FIFO_CNT(bytes);
+	bytes = bytes  & 0xFFFC; /* io in multiple of 4 bytes */
+	if (info->iomode == OMAP_NAND_IO_WRITE) { /* checks for write io */
+		if (this_irq == info->gpmc_irq_count)
+			goto done;
+
+		if (info->buf_len && (info->buf_len < bytes))
+			bytes = info->buf_len;
+		else if (!info->buf_len)
+			bytes = 0;
+		iowrite32_rep(info->nand.IO_ADDR_W,
+						(u32 *)info->buf, bytes >> 2);
+		info->buf = info->buf + bytes;
+		info->buf_len -= bytes;
+
+	} else {
+		ioread32_rep(info->nand.IO_ADDR_R,
+						(u32 *)info->buf, bytes >> 2);
+		info->buf = info->buf + bytes;
+
+		if (this_irq == info->gpmc_irq_count)
+			goto done;
+	}
+
+	return IRQ_HANDLED;
+
+done:
+	complete(&info->comp);
+
+	disable_irq_nosync(info->gpmc_irq_fifo);
+	disable_irq_nosync(info->gpmc_irq_count);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * omap_read_buf_irq_pref - read data from NAND controller into buffer
+ * @mtd: MTD device structure
+ * @buf: buffer to store date
+ * @len: number of bytes to read
+ */
+static void omap_read_buf_irq_pref(struct mtd_info *mtd, u_char *buf, int len)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	int ret = 0;
+
+	if (len <= mtd->oobsize) {
+		omap_read_buf_pref(mtd, buf, len);
+		return;
+	}
+
+	info->iomode = OMAP_NAND_IO_READ;
+	info->buf = buf;
+	init_completion(&info->comp);
+
+	/*  configure and start prefetch transfer */
+	ret = omap_prefetch_enable(info->gpmc_cs,
+			PREFETCH_FIFOTHRESHOLD_MAX/2, 0x0, len, 0x0, info);
+	if (ret)
+		/* PFPW engine is busy, use cpu copy method */
+		goto out_copy;
+
+	info->buf_len = len;
+
+	enable_irq(info->gpmc_irq_count);
+	enable_irq(info->gpmc_irq_fifo);
+
+	/* waiting for read to complete */
+	wait_for_completion(&info->comp);
+
+	/* disable and stop the PFPW engine */
+	omap_prefetch_reset(info->gpmc_cs, info);
+	return;
+
+out_copy:
+	if (info->nand.options & NAND_BUSWIDTH_16)
+		omap_read_buf16(mtd, buf, len);
+	else
+		omap_read_buf8(mtd, buf, len);
+}
+
+/*
+ * omap_write_buf_irq_pref - write buffer to NAND controller
+ * @mtd: MTD device structure
+ * @buf: data buffer
+ * @len: number of bytes to write
+ */
+static void omap_write_buf_irq_pref(struct mtd_info *mtd,
+					const u_char *buf, int len)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	int ret = 0;
+	unsigned long tim, limit;
+	u32 val;
+
+	if (len <= mtd->oobsize) {
+		omap_write_buf_pref(mtd, buf, len);
+		return;
+	}
+
+	info->iomode = OMAP_NAND_IO_WRITE;
+	info->buf = (u_char *) buf;
+	init_completion(&info->comp);
+
+	/* configure and start prefetch transfer : size=24 */
+	ret = omap_prefetch_enable(info->gpmc_cs,
+		(PREFETCH_FIFOTHRESHOLD_MAX * 3) / 8, 0x0, len, 0x1, info);
+	if (ret)
+		/* PFPW engine is busy, use cpu copy method */
+		goto out_copy;
+
+	info->buf_len = len;
+
+	enable_irq(info->gpmc_irq_count);
+	enable_irq(info->gpmc_irq_fifo);
+
+	/* waiting for write to complete */
+	wait_for_completion(&info->comp);
+
+	/* wait for data to flushed-out before reset the prefetch */
+	tim = 0;
+	limit = (loops_per_jiffy *  msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
+	do {
+		val = readl(info->reg.gpmc_prefetch_status);
+		val = PREFETCH_STATUS_COUNT(val);
+		cpu_relax();
+	} while (val && (tim++ < limit));
+
+	/* disable and stop the PFPW engine */
+	omap_prefetch_reset(info->gpmc_cs, info);
+	return;
+
+out_copy:
+	if (info->nand.options & NAND_BUSWIDTH_16)
+		omap_write_buf16(mtd, buf, len);
+	else
+		omap_write_buf8(mtd, buf, len);
+}
+
+/**
+ * gen_true_ecc - This function will generate true ECC value
+ * @ecc_buf: buffer to store ecc code
+ *
+ * This generated true ECC value can be used when correcting
+ * data read from NAND flash memory core
+ */
+static void gen_true_ecc(u8 *ecc_buf)
+{
+	u32 tmp = ecc_buf[0] | (ecc_buf[1] << 16) |
+		((ecc_buf[2] & 0xF0) << 20) | ((ecc_buf[2] & 0x0F) << 8);
+
+	ecc_buf[0] = ~(P64o(tmp) | P64e(tmp) | P32o(tmp) | P32e(tmp) |
+			P16o(tmp) | P16e(tmp) | P8o(tmp) | P8e(tmp));
+	ecc_buf[1] = ~(P1024o(tmp) | P1024e(tmp) | P512o(tmp) | P512e(tmp) |
+			P256o(tmp) | P256e(tmp) | P128o(tmp) | P128e(tmp));
+	ecc_buf[2] = ~(P4o(tmp) | P4e(tmp) | P2o(tmp) | P2e(tmp) | P1o(tmp) |
+			P1e(tmp) | P2048o(tmp) | P2048e(tmp));
+}
+
+/**
+ * omap_compare_ecc - Detect (2 bits) and correct (1 bit) error in data
+ * @ecc_data1:  ecc code from nand spare area
+ * @ecc_data2:  ecc code from hardware register obtained from hardware ecc
+ * @page_data:  page data
+ *
+ * This function compares two ECC's and indicates if there is an error.
+ * If the error can be corrected it will be corrected to the buffer.
+ * If there is no error, %0 is returned. If there is an error but it
+ * was corrected, %1 is returned. Otherwise, %-1 is returned.
+ */
+static int omap_compare_ecc(u8 *ecc_data1,	/* read from NAND memory */
+			    u8 *ecc_data2,	/* read from register */
+			    u8 *page_data)
+{
+	uint	i;
+	u8	tmp0_bit[8], tmp1_bit[8], tmp2_bit[8];
+	u8	comp0_bit[8], comp1_bit[8], comp2_bit[8];
+	u8	ecc_bit[24];
+	u8	ecc_sum = 0;
+	u8	find_bit = 0;
+	uint	find_byte = 0;
+	int	isEccFF;
+
+	isEccFF = ((*(u32 *)ecc_data1 & 0xFFFFFF) == 0xFFFFFF);
+
+	gen_true_ecc(ecc_data1);
+	gen_true_ecc(ecc_data2);
+
+	for (i = 0; i <= 2; i++) {
+		*(ecc_data1 + i) = ~(*(ecc_data1 + i));
+		*(ecc_data2 + i) = ~(*(ecc_data2 + i));
+	}
+
+	for (i = 0; i < 8; i++) {
+		tmp0_bit[i]     = *ecc_data1 % 2;
+		*ecc_data1	= *ecc_data1 / 2;
+	}
+
+	for (i = 0; i < 8; i++) {
+		tmp1_bit[i]	 = *(ecc_data1 + 1) % 2;
+		*(ecc_data1 + 1) = *(ecc_data1 + 1) / 2;
+	}
+
+	for (i = 0; i < 8; i++) {
+		tmp2_bit[i]	 = *(ecc_data1 + 2) % 2;
+		*(ecc_data1 + 2) = *(ecc_data1 + 2) / 2;
+	}
+
+	for (i = 0; i < 8; i++) {
+		comp0_bit[i]     = *ecc_data2 % 2;
+		*ecc_data2       = *ecc_data2 / 2;
+	}
+
+	for (i = 0; i < 8; i++) {
+		comp1_bit[i]     = *(ecc_data2 + 1) % 2;
+		*(ecc_data2 + 1) = *(ecc_data2 + 1) / 2;
+	}
+
+	for (i = 0; i < 8; i++) {
+		comp2_bit[i]     = *(ecc_data2 + 2) % 2;
+		*(ecc_data2 + 2) = *(ecc_data2 + 2) / 2;
+	}
+
+	for (i = 0; i < 6; i++)
+		ecc_bit[i] = tmp2_bit[i + 2] ^ comp2_bit[i + 2];
+
+	for (i = 0; i < 8; i++)
+		ecc_bit[i + 6] = tmp0_bit[i] ^ comp0_bit[i];
+
+	for (i = 0; i < 8; i++)
+		ecc_bit[i + 14] = tmp1_bit[i] ^ comp1_bit[i];
+
+	ecc_bit[22] = tmp2_bit[0] ^ comp2_bit[0];
+	ecc_bit[23] = tmp2_bit[1] ^ comp2_bit[1];
+
+	for (i = 0; i < 24; i++)
+		ecc_sum += ecc_bit[i];
+
+	switch (ecc_sum) {
+	case 0:
+		/* Not reached because this function is not called if
+		 *  ECC values are equal
+		 */
+		return 0;
+
+	case 1:
+		/* Uncorrectable error */
+		pr_debug("ECC UNCORRECTED_ERROR 1\n");
+		return -EBADMSG;
+
+	case 11:
+		/* UN-Correctable error */
+		pr_debug("ECC UNCORRECTED_ERROR B\n");
+		return -EBADMSG;
+
+	case 12:
+		/* Correctable error */
+		find_byte = (ecc_bit[23] << 8) +
+			    (ecc_bit[21] << 7) +
+			    (ecc_bit[19] << 6) +
+			    (ecc_bit[17] << 5) +
+			    (ecc_bit[15] << 4) +
+			    (ecc_bit[13] << 3) +
+			    (ecc_bit[11] << 2) +
+			    (ecc_bit[9]  << 1) +
+			    ecc_bit[7];
+
+		find_bit = (ecc_bit[5] << 2) + (ecc_bit[3] << 1) + ecc_bit[1];
+
+		pr_debug("Correcting single bit ECC error at offset: "
+				"%d, bit: %d\n", find_byte, find_bit);
+
+		page_data[find_byte] ^= (1 << find_bit);
+
+		return 1;
+	default:
+		if (isEccFF) {
+			if (ecc_data2[0] == 0 &&
+			    ecc_data2[1] == 0 &&
+			    ecc_data2[2] == 0)
+				return 0;
+		}
+		pr_debug("UNCORRECTED_ERROR default\n");
+		return -EBADMSG;
+	}
+}
+
+/**
+ * omap_correct_data - Compares the ECC read with HW generated ECC
+ * @mtd: MTD device structure
+ * @dat: page data
+ * @read_ecc: ecc read from nand flash
+ * @calc_ecc: ecc read from HW ECC registers
+ *
+ * Compares the ecc read from nand spare area with ECC registers values
+ * and if ECC's mismatched, it will call 'omap_compare_ecc' for error
+ * detection and correction. If there are no errors, %0 is returned. If
+ * there were errors and all of the errors were corrected, the number of
+ * corrected errors is returned. If uncorrectable errors exist, %-1 is
+ * returned.
+ */
+static int omap_correct_data(struct mtd_info *mtd, u_char *dat,
+				u_char *read_ecc, u_char *calc_ecc)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	int blockCnt = 0, i = 0, ret = 0;
+	int stat = 0;
+
+	/* Ex NAND_ECC_HW12_2048 */
+	if ((info->nand.ecc.mode == NAND_ECC_HW) &&
+			(info->nand.ecc.size  == 2048))
+		blockCnt = 4;
+	else
+		blockCnt = 1;
+
+	for (i = 0; i < blockCnt; i++) {
+		if (memcmp(read_ecc, calc_ecc, 3) != 0) {
+			ret = omap_compare_ecc(read_ecc, calc_ecc, dat);
+			if (ret < 0)
+				return ret;
+			/* keep track of the number of corrected errors */
+			stat += ret;
+		}
+		read_ecc += 3;
+		calc_ecc += 3;
+		dat      += 512;
+	}
+	return stat;
+}
+
+/**
+ * omap_calcuate_ecc - Generate non-inverted ECC bytes.
+ * @mtd: MTD device structure
+ * @dat: The pointer to data on which ecc is computed
+ * @ecc_code: The ecc_code buffer
+ *
+ * Using noninverted ECC can be considered ugly since writing a blank
+ * page ie. padding will clear the ECC bytes. This is no problem as long
+ * nobody is trying to write data on the seemingly unused page. Reading
+ * an erased page will produce an ECC mismatch between generated and read
+ * ECC bytes that has to be dealt with separately.
+ */
+static int omap_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
+				u_char *ecc_code)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	u32 val;
+
+	val = readl(info->reg.gpmc_ecc_config);
+	if (((val >> ECC_CONFIG_CS_SHIFT) & CS_MASK) != info->gpmc_cs)
+		return -EINVAL;
+
+	/* read ecc result */
+	val = readl(info->reg.gpmc_ecc1_result);
+	*ecc_code++ = val;          /* P128e, ..., P1e */
+	*ecc_code++ = val >> 16;    /* P128o, ..., P1o */
+	/* P2048o, P1024o, P512o, P256o, P2048e, P1024e, P512e, P256e */
+	*ecc_code++ = ((val >> 8) & 0x0f) | ((val >> 20) & 0xf0);
+
+	return 0;
+}
+
+/**
+ * omap_enable_hwecc - This function enables the hardware ecc functionality
+ * @mtd: MTD device structure
+ * @mode: Read/Write mode
+ */
+static void omap_enable_hwecc(struct mtd_info *mtd, int mode)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	unsigned int dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
+	u32 val;
+
+	/* clear ecc and enable bits */
+	val = ECCCLEAR | ECC1;
+	writel(val, info->reg.gpmc_ecc_control);
+
+	/* program ecc and result sizes */
+	val = ((((info->nand.ecc.size >> 1) - 1) << ECCSIZE1_SHIFT) |
+			 ECC1RESULTSIZE);
+	writel(val, info->reg.gpmc_ecc_size_config);
+
+	switch (mode) {
+	case NAND_ECC_READ:
+	case NAND_ECC_WRITE:
+		writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
+		break;
+	case NAND_ECC_READSYN:
+		writel(ECCCLEAR, info->reg.gpmc_ecc_control);
+		break;
+	default:
+		dev_info(&info->pdev->dev,
+			"error: unrecognized Mode[%d]!\n", mode);
+		break;
+	}
+
+	/* (ECC 16 or 8 bit col) | ( CS  )  | ECC Enable */
+	val = (dev_width << 7) | (info->gpmc_cs << 1) | (0x1);
+	writel(val, info->reg.gpmc_ecc_config);
+}
+
+/**
+ * omap_wait - wait until the command is done
+ * @mtd: MTD device structure
+ * @chip: NAND Chip structure
+ *
+ * Wait function is called during Program and erase operations and
+ * the way it is called from MTD layer, we should wait till the NAND
+ * chip is ready after the programming/erase operation has completed.
+ *
+ * Erase can take up to 400ms and program up to 20ms according to
+ * general NAND and SmartMedia specs
+ */
+static int omap_wait(struct mtd_info *mtd, struct nand_chip *chip)
+{
+	struct nand_chip *this = mtd_to_nand(mtd);
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	unsigned long timeo = jiffies;
+	int status, state = this->state;
+
+	if (state == FL_ERASING)
+		timeo += msecs_to_jiffies(400);
+	else
+		timeo += msecs_to_jiffies(20);
+
+	writeb(NAND_CMD_STATUS & 0xFF, info->reg.gpmc_nand_command);
+	while (time_before(jiffies, timeo)) {
+		status = readb(info->reg.gpmc_nand_data);
+		if (status & NAND_STATUS_READY)
+			break;
+		cond_resched();
+	}
+
+	status = readb(info->reg.gpmc_nand_data);
+	return status;
+}
+
+/**
+ * omap_dev_ready - checks the NAND Ready GPIO line
+ * @mtd: MTD device structure
+ *
+ * Returns true if ready and false if busy.
+ */
+static int omap_dev_ready(struct mtd_info *mtd)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+
+	return gpiod_get_value(info->ready_gpiod);
+}
+
+/**
+ * omap_enable_hwecc_bch - Program GPMC to perform BCH ECC calculation
+ * @mtd: MTD device structure
+ * @mode: Read/Write mode
+ *
+ * When using BCH with SW correction (i.e. no ELM), sector size is set
+ * to 512 bytes and we use BCH_WRAPMODE_6 wrapping mode
+ * for both reading and writing with:
+ * eccsize0 = 0  (no additional protected byte in spare area)
+ * eccsize1 = 32 (skip 32 nibbles = 16 bytes per sector in spare area)
+ */
+static void __maybe_unused omap_enable_hwecc_bch(struct mtd_info *mtd, int mode)
+{
+	unsigned int bch_type;
+	unsigned int dev_width, nsectors;
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	enum omap_ecc ecc_opt = info->ecc_opt;
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	u32 val, wr_mode;
+	unsigned int ecc_size1, ecc_size0;
+
+	/* GPMC configurations for calculating ECC */
+	switch (ecc_opt) {
+	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
+		bch_type = 0;
+		nsectors = 1;
+		wr_mode	  = BCH_WRAPMODE_6;
+		ecc_size0 = BCH_ECC_SIZE0;
+		ecc_size1 = BCH_ECC_SIZE1;
+		break;
+	case OMAP_ECC_BCH4_CODE_HW:
+		bch_type = 0;
+		nsectors = chip->ecc.steps;
+		if (mode == NAND_ECC_READ) {
+			wr_mode	  = BCH_WRAPMODE_1;
+			ecc_size0 = BCH4R_ECC_SIZE0;
+			ecc_size1 = BCH4R_ECC_SIZE1;
+		} else {
+			wr_mode   = BCH_WRAPMODE_6;
+			ecc_size0 = BCH_ECC_SIZE0;
+			ecc_size1 = BCH_ECC_SIZE1;
+		}
+		break;
+	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
+		bch_type = 1;
+		nsectors = 1;
+		wr_mode	  = BCH_WRAPMODE_6;
+		ecc_size0 = BCH_ECC_SIZE0;
+		ecc_size1 = BCH_ECC_SIZE1;
+		break;
+	case OMAP_ECC_BCH8_CODE_HW:
+		bch_type = 1;
+		nsectors = chip->ecc.steps;
+		if (mode == NAND_ECC_READ) {
+			wr_mode	  = BCH_WRAPMODE_1;
+			ecc_size0 = BCH8R_ECC_SIZE0;
+			ecc_size1 = BCH8R_ECC_SIZE1;
+		} else {
+			wr_mode   = BCH_WRAPMODE_6;
+			ecc_size0 = BCH_ECC_SIZE0;
+			ecc_size1 = BCH_ECC_SIZE1;
+		}
+		break;
+	case OMAP_ECC_BCH16_CODE_HW:
+		bch_type = 0x2;
+		nsectors = chip->ecc.steps;
+		if (mode == NAND_ECC_READ) {
+			wr_mode	  = 0x01;
+			ecc_size0 = 52; /* ECC bits in nibbles per sector */
+			ecc_size1 = 0;  /* non-ECC bits in nibbles per sector */
+		} else {
+			wr_mode	  = 0x01;
+			ecc_size0 = 0;  /* extra bits in nibbles per sector */
+			ecc_size1 = 52; /* OOB bits in nibbles per sector */
+		}
+		break;
+	default:
+		return;
+	}
+
+	writel(ECC1, info->reg.gpmc_ecc_control);
+
+	/* Configure ecc size for BCH */
+	val = (ecc_size1 << ECCSIZE1_SHIFT) | (ecc_size0 << ECCSIZE0_SHIFT);
+	writel(val, info->reg.gpmc_ecc_size_config);
+
+	dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
+
+	/* BCH configuration */
+	val = ((1                        << 16) | /* enable BCH */
+	       (bch_type		 << 12) | /* BCH4/BCH8/BCH16 */
+	       (wr_mode                  <<  8) | /* wrap mode */
+	       (dev_width                <<  7) | /* bus width */
+	       (((nsectors-1) & 0x7)     <<  4) | /* number of sectors */
+	       (info->gpmc_cs            <<  1) | /* ECC CS */
+	       (0x1));                            /* enable ECC */
+
+	writel(val, info->reg.gpmc_ecc_config);
+
+	/* Clear ecc and enable bits */
+	writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
+}
+
+static u8  bch4_polynomial[] = {0x28, 0x13, 0xcc, 0x39, 0x96, 0xac, 0x7f};
+static u8  bch8_polynomial[] = {0xef, 0x51, 0x2e, 0x09, 0xed, 0x93, 0x9a, 0xc2,
+				0x97, 0x79, 0xe5, 0x24, 0xb5};
+
+/**
+ * _omap_calculate_ecc_bch - Generate ECC bytes for one sector
+ * @mtd:	MTD device structure
+ * @dat:	The pointer to data on which ecc is computed
+ * @ecc_code:	The ecc_code buffer
+ * @i:		The sector number (for a multi sector page)
+ *
+ * Support calculating of BCH4/8/16 ECC vectors for one sector
+ * within a page. Sector number is in @i.
+ */
+static int _omap_calculate_ecc_bch(struct mtd_info *mtd,
+				   const u_char *dat, u_char *ecc_calc, int i)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	int eccbytes	= info->nand.ecc.bytes;
+	struct gpmc_nand_regs	*gpmc_regs = &info->reg;
+	u8 *ecc_code;
+	unsigned long bch_val1, bch_val2, bch_val3, bch_val4;
+	u32 val;
+	int j;
+
+	ecc_code = ecc_calc;
+	switch (info->ecc_opt) {
+	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
+	case OMAP_ECC_BCH8_CODE_HW:
+		bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
+		bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
+		bch_val3 = readl(gpmc_regs->gpmc_bch_result2[i]);
+		bch_val4 = readl(gpmc_regs->gpmc_bch_result3[i]);
+		*ecc_code++ = (bch_val4 & 0xFF);
+		*ecc_code++ = ((bch_val3 >> 24) & 0xFF);
+		*ecc_code++ = ((bch_val3 >> 16) & 0xFF);
+		*ecc_code++ = ((bch_val3 >> 8) & 0xFF);
+		*ecc_code++ = (bch_val3 & 0xFF);
+		*ecc_code++ = ((bch_val2 >> 24) & 0xFF);
+		*ecc_code++ = ((bch_val2 >> 16) & 0xFF);
+		*ecc_code++ = ((bch_val2 >> 8) & 0xFF);
+		*ecc_code++ = (bch_val2 & 0xFF);
+		*ecc_code++ = ((bch_val1 >> 24) & 0xFF);
+		*ecc_code++ = ((bch_val1 >> 16) & 0xFF);
+		*ecc_code++ = ((bch_val1 >> 8) & 0xFF);
+		*ecc_code++ = (bch_val1 & 0xFF);
+		break;
+	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
+	case OMAP_ECC_BCH4_CODE_HW:
+		bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
+		bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
+		*ecc_code++ = ((bch_val2 >> 12) & 0xFF);
+		*ecc_code++ = ((bch_val2 >> 4) & 0xFF);
+		*ecc_code++ = ((bch_val2 & 0xF) << 4) |
+			((bch_val1 >> 28) & 0xF);
+		*ecc_code++ = ((bch_val1 >> 20) & 0xFF);
+		*ecc_code++ = ((bch_val1 >> 12) & 0xFF);
+		*ecc_code++ = ((bch_val1 >> 4) & 0xFF);
+		*ecc_code++ = ((bch_val1 & 0xF) << 4);
+		break;
+	case OMAP_ECC_BCH16_CODE_HW:
+		val = readl(gpmc_regs->gpmc_bch_result6[i]);
+		ecc_code[0]  = ((val >>  8) & 0xFF);
+		ecc_code[1]  = ((val >>  0) & 0xFF);
+		val = readl(gpmc_regs->gpmc_bch_result5[i]);
+		ecc_code[2]  = ((val >> 24) & 0xFF);
+		ecc_code[3]  = ((val >> 16) & 0xFF);
+		ecc_code[4]  = ((val >>  8) & 0xFF);
+		ecc_code[5]  = ((val >>  0) & 0xFF);
+		val = readl(gpmc_regs->gpmc_bch_result4[i]);
+		ecc_code[6]  = ((val >> 24) & 0xFF);
+		ecc_code[7]  = ((val >> 16) & 0xFF);
+		ecc_code[8]  = ((val >>  8) & 0xFF);
+		ecc_code[9]  = ((val >>  0) & 0xFF);
+		val = readl(gpmc_regs->gpmc_bch_result3[i]);
+		ecc_code[10] = ((val >> 24) & 0xFF);
+		ecc_code[11] = ((val >> 16) & 0xFF);
+		ecc_code[12] = ((val >>  8) & 0xFF);
+		ecc_code[13] = ((val >>  0) & 0xFF);
+		val = readl(gpmc_regs->gpmc_bch_result2[i]);
+		ecc_code[14] = ((val >> 24) & 0xFF);
+		ecc_code[15] = ((val >> 16) & 0xFF);
+		ecc_code[16] = ((val >>  8) & 0xFF);
+		ecc_code[17] = ((val >>  0) & 0xFF);
+		val = readl(gpmc_regs->gpmc_bch_result1[i]);
+		ecc_code[18] = ((val >> 24) & 0xFF);
+		ecc_code[19] = ((val >> 16) & 0xFF);
+		ecc_code[20] = ((val >>  8) & 0xFF);
+		ecc_code[21] = ((val >>  0) & 0xFF);
+		val = readl(gpmc_regs->gpmc_bch_result0[i]);
+		ecc_code[22] = ((val >> 24) & 0xFF);
+		ecc_code[23] = ((val >> 16) & 0xFF);
+		ecc_code[24] = ((val >>  8) & 0xFF);
+		ecc_code[25] = ((val >>  0) & 0xFF);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* ECC scheme specific syndrome customizations */
+	switch (info->ecc_opt) {
+	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
+		/* Add constant polynomial to remainder, so that
+		 * ECC of blank pages results in 0x0 on reading back
+		 */
+		for (j = 0; j < eccbytes; j++)
+			ecc_calc[j] ^= bch4_polynomial[j];
+		break;
+	case OMAP_ECC_BCH4_CODE_HW:
+		/* Set  8th ECC byte as 0x0 for ROM compatibility */
+		ecc_calc[eccbytes - 1] = 0x0;
+		break;
+	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
+		/* Add constant polynomial to remainder, so that
+		 * ECC of blank pages results in 0x0 on reading back
+		 */
+		for (j = 0; j < eccbytes; j++)
+			ecc_calc[j] ^= bch8_polynomial[j];
+		break;
+	case OMAP_ECC_BCH8_CODE_HW:
+		/* Set 14th ECC byte as 0x0 for ROM compatibility */
+		ecc_calc[eccbytes - 1] = 0x0;
+		break;
+	case OMAP_ECC_BCH16_CODE_HW:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * omap_calculate_ecc_bch_sw - ECC generator for sector for SW based correction
+ * @mtd:	MTD device structure
+ * @dat:	The pointer to data on which ecc is computed
+ * @ecc_code:	The ecc_code buffer
+ *
+ * Support calculating of BCH4/8/16 ECC vectors for one sector. This is used
+ * when SW based correction is required as ECC is required for one sector
+ * at a time.
+ */
+static int omap_calculate_ecc_bch_sw(struct mtd_info *mtd,
+				     const u_char *dat, u_char *ecc_calc)
+{
+	return _omap_calculate_ecc_bch(mtd, dat, ecc_calc, 0);
+}
+
+/**
+ * omap_calculate_ecc_bch_multi - Generate ECC for multiple sectors
+ * @mtd:	MTD device structure
+ * @dat:	The pointer to data on which ecc is computed
+ * @ecc_code:	The ecc_code buffer
+ *
+ * Support calculating of BCH4/8/16 ecc vectors for the entire page in one go.
+ */
+static int omap_calculate_ecc_bch_multi(struct mtd_info *mtd,
+					const u_char *dat, u_char *ecc_calc)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	int eccbytes = info->nand.ecc.bytes;
+	unsigned long nsectors;
+	int i, ret;
+
+	nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
+	for (i = 0; i < nsectors; i++) {
+		ret = _omap_calculate_ecc_bch(mtd, dat, ecc_calc, i);
+		if (ret)
+			return ret;
+
+		ecc_calc += eccbytes;
+	}
+
+	return 0;
+}
+
+/**
+ * erased_sector_bitflips - count bit flips
+ * @data:	data sector buffer
+ * @oob:	oob buffer
+ * @info:	omap_nand_info
+ *
+ * Check the bit flips in erased page falls below correctable level.
+ * If falls below, report the page as erased with correctable bit
+ * flip, else report as uncorrectable page.
+ */
+static int erased_sector_bitflips(u_char *data, u_char *oob,
+		struct omap_nand_info *info)
+{
+	int flip_bits = 0, i;
+
+	for (i = 0; i < info->nand.ecc.size; i++) {
+		flip_bits += hweight8(~data[i]);
+		if (flip_bits > info->nand.ecc.strength)
+			return 0;
+	}
+
+	for (i = 0; i < info->nand.ecc.bytes - 1; i++) {
+		flip_bits += hweight8(~oob[i]);
+		if (flip_bits > info->nand.ecc.strength)
+			return 0;
+	}
+
+	/*
+	 * Bit flips falls in correctable level.
+	 * Fill data area with 0xFF
+	 */
+	if (flip_bits) {
+		memset(data, 0xFF, info->nand.ecc.size);
+		memset(oob, 0xFF, info->nand.ecc.bytes);
+	}
+
+	return flip_bits;
+}
+
+/**
+ * omap_elm_correct_data - corrects page data area in case error reported
+ * @mtd:	MTD device structure
+ * @data:	page data
+ * @read_ecc:	ecc read from nand flash
+ * @calc_ecc:	ecc read from HW ECC registers
+ *
+ * Calculated ecc vector reported as zero in case of non-error pages.
+ * In case of non-zero ecc vector, first filter out erased-pages, and
+ * then process data via ELM to detect bit-flips.
+ */
+static int omap_elm_correct_data(struct mtd_info *mtd, u_char *data,
+				u_char *read_ecc, u_char *calc_ecc)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	struct nand_ecc_ctrl *ecc = &info->nand.ecc;
+	int eccsteps = info->nand.ecc.steps;
+	int i , j, stat = 0;
+	int eccflag, actual_eccbytes;
+	struct elm_errorvec err_vec[ERROR_VECTOR_MAX];
+	u_char *ecc_vec = calc_ecc;
+	u_char *spare_ecc = read_ecc;
+	u_char *erased_ecc_vec;
+	u_char *buf;
+	int bitflip_count;
+	bool is_error_reported = false;
+	u32 bit_pos, byte_pos, error_max, pos;
+	int err;
+
+	switch (info->ecc_opt) {
+	case OMAP_ECC_BCH4_CODE_HW:
+		/* omit  7th ECC byte reserved for ROM code compatibility */
+		actual_eccbytes = ecc->bytes - 1;
+		erased_ecc_vec = bch4_vector;
+		break;
+	case OMAP_ECC_BCH8_CODE_HW:
+		/* omit 14th ECC byte reserved for ROM code compatibility */
+		actual_eccbytes = ecc->bytes - 1;
+		erased_ecc_vec = bch8_vector;
+		break;
+	case OMAP_ECC_BCH16_CODE_HW:
+		actual_eccbytes = ecc->bytes;
+		erased_ecc_vec = bch16_vector;
+		break;
+	default:
+		dev_err(&info->pdev->dev, "invalid driver configuration\n");
+		return -EINVAL;
+	}
+
+	/* Initialize elm error vector to zero */
+	memset(err_vec, 0, sizeof(err_vec));
+
+	for (i = 0; i < eccsteps ; i++) {
+		eccflag = 0;	/* initialize eccflag */
+
+		/*
+		 * Check any error reported,
+		 * In case of error, non zero ecc reported.
+		 */
+		for (j = 0; j < actual_eccbytes; j++) {
+			if (calc_ecc[j] != 0) {
+				eccflag = 1; /* non zero ecc, error present */
+				break;
+			}
+		}
+
+		if (eccflag == 1) {
+			if (memcmp(calc_ecc, erased_ecc_vec,
+						actual_eccbytes) == 0) {
+				/*
+				 * calc_ecc[] matches pattern for ECC(all 0xff)
+				 * so this is definitely an erased-page
+				 */
+			} else {
+				buf = &data[info->nand.ecc.size * i];
+				/*
+				 * count number of 0-bits in read_buf.
+				 * This check can be removed once a similar
+				 * check is introduced in generic NAND driver
+				 */
+				bitflip_count = erased_sector_bitflips(
+						buf, read_ecc, info);
+				if (bitflip_count) {
+					/*
+					 * number of 0-bits within ECC limits
+					 * So this may be an erased-page
+					 */
+					stat += bitflip_count;
+				} else {
+					/*
+					 * Too many 0-bits. It may be a
+					 * - programmed-page, OR
+					 * - erased-page with many bit-flips
+					 * So this page requires check by ELM
+					 */
+					err_vec[i].error_reported = true;
+					is_error_reported = true;
+				}
+			}
+		}
+
+		/* Update the ecc vector */
+		calc_ecc += ecc->bytes;
+		read_ecc += ecc->bytes;
+	}
+
+	/* Check if any error reported */
+	if (!is_error_reported)
+		return stat;
+
+	/* Decode BCH error using ELM module */
+	elm_decode_bch_error_page(info->elm_dev, ecc_vec, err_vec);
+
+	err = 0;
+	for (i = 0; i < eccsteps; i++) {
+		if (err_vec[i].error_uncorrectable) {
+			dev_err(&info->pdev->dev,
+				"uncorrectable bit-flips found\n");
+			err = -EBADMSG;
+		} else if (err_vec[i].error_reported) {
+			for (j = 0; j < err_vec[i].error_count; j++) {
+				switch (info->ecc_opt) {
+				case OMAP_ECC_BCH4_CODE_HW:
+					/* Add 4 bits to take care of padding */
+					pos = err_vec[i].error_loc[j] +
+						BCH4_BIT_PAD;
+					break;
+				case OMAP_ECC_BCH8_CODE_HW:
+				case OMAP_ECC_BCH16_CODE_HW:
+					pos = err_vec[i].error_loc[j];
+					break;
+				default:
+					return -EINVAL;
+				}
+				error_max = (ecc->size + actual_eccbytes) * 8;
+				/* Calculate bit position of error */
+				bit_pos = pos % 8;
+
+				/* Calculate byte position of error */
+				byte_pos = (error_max - pos - 1) / 8;
+
+				if (pos < error_max) {
+					if (byte_pos < 512) {
+						pr_debug("bitflip@dat[%d]=%x\n",
+						     byte_pos, data[byte_pos]);
+						data[byte_pos] ^= 1 << bit_pos;
+					} else {
+						pr_debug("bitflip@oob[%d]=%x\n",
+							(byte_pos - 512),
+						     spare_ecc[byte_pos - 512]);
+						spare_ecc[byte_pos - 512] ^=
+							1 << bit_pos;
+					}
+				} else {
+					dev_err(&info->pdev->dev,
+						"invalid bit-flip @ %d:%d\n",
+						byte_pos, bit_pos);
+					err = -EBADMSG;
+				}
+			}
+		}
+
+		/* Update number of correctable errors */
+		stat += err_vec[i].error_count;
+
+		/* Update page data with sector size */
+		data += ecc->size;
+		spare_ecc += ecc->bytes;
+	}
+
+	return (err) ? err : stat;
+}
+
+/**
+ * omap_write_page_bch - BCH ecc based write page function for entire page
+ * @mtd:		mtd info structure
+ * @chip:		nand chip info structure
+ * @buf:		data buffer
+ * @oob_required:	must write chip->oob_poi to OOB
+ * @page:		page
+ *
+ * Custom write page method evolved to support multi sector writing in one shot
+ */
+static int omap_write_page_bch(struct mtd_info *mtd, struct nand_chip *chip,
+			       const uint8_t *buf, int oob_required, int page)
+{
+	int ret;
+	uint8_t *ecc_calc = chip->ecc.calc_buf;
+
+	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
+
+	/* Enable GPMC ecc engine */
+	chip->ecc.hwctl(mtd, NAND_ECC_WRITE);
+
+	/* Write data */
+	chip->write_buf(mtd, buf, mtd->writesize);
+
+	/* Update ecc vector from GPMC result registers */
+	omap_calculate_ecc_bch_multi(mtd, buf, &ecc_calc[0]);
+
+	ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc, chip->oob_poi, 0,
+					 chip->ecc.total);
+	if (ret)
+		return ret;
+
+	/* Write ecc vector to OOB area */
+	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
+
+	return nand_prog_page_end_op(chip);
+}
+
+/**
+ * omap_write_subpage_bch - BCH hardware ECC based subpage write
+ * @mtd:	mtd info structure
+ * @chip:	nand chip info structure
+ * @offset:	column address of subpage within the page
+ * @data_len:	data length
+ * @buf:	data buffer
+ * @oob_required: must write chip->oob_poi to OOB
+ * @page: page number to write
+ *
+ * OMAP optimized subpage write method.
+ */
+static int omap_write_subpage_bch(struct mtd_info *mtd,
+				  struct nand_chip *chip, u32 offset,
+				  u32 data_len, const u8 *buf,
+				  int oob_required, int page)
+{
+	u8 *ecc_calc = chip->ecc.calc_buf;
+	int ecc_size      = chip->ecc.size;
+	int ecc_bytes     = chip->ecc.bytes;
+	int ecc_steps     = chip->ecc.steps;
+	u32 start_step = offset / ecc_size;
+	u32 end_step   = (offset + data_len - 1) / ecc_size;
+	int step, ret = 0;
+
+	/*
+	 * Write entire page at one go as it would be optimal
+	 * as ECC is calculated by hardware.
+	 * ECC is calculated for all subpages but we choose
+	 * only what we want.
+	 */
+	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
+
+	/* Enable GPMC ECC engine */
+	chip->ecc.hwctl(mtd, NAND_ECC_WRITE);
+
+	/* Write data */
+	chip->write_buf(mtd, buf, mtd->writesize);
+
+	for (step = 0; step < ecc_steps; step++) {
+		/* mask ECC of un-touched subpages by padding 0xFF */
+		if (step < start_step || step > end_step)
+			memset(ecc_calc, 0xff, ecc_bytes);
+		else
+			ret = _omap_calculate_ecc_bch(mtd, buf, ecc_calc, step);
+
+		if (ret)
+			return ret;
+
+		buf += ecc_size;
+		ecc_calc += ecc_bytes;
+	}
+
+	/* copy calculated ECC for whole page to chip->buffer->oob */
+	/* this include masked-value(0xFF) for unwritten subpages */
+	ecc_calc = chip->ecc.calc_buf;
+	ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc, chip->oob_poi, 0,
+					 chip->ecc.total);
+	if (ret)
+		return ret;
+
+	/* write OOB buffer to NAND device */
+	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
+
+	return nand_prog_page_end_op(chip);
+}
+
+/**
+ * omap_read_page_bch - BCH ecc based page read function for entire page
+ * @mtd:		mtd info structure
+ * @chip:		nand chip info structure
+ * @buf:		buffer to store read data
+ * @oob_required:	caller requires OOB data read to chip->oob_poi
+ * @page:		page number to read
+ *
+ * For BCH ecc scheme, GPMC used for syndrome calculation and ELM module
+ * used for error correction.
+ * Custom method evolved to support ELM error correction & multi sector
+ * reading. On reading page data area is read along with OOB data with
+ * ecc engine enabled. ecc vector updated after read of OOB data.
+ * For non error pages ecc vector reported as zero.
+ */
+static int omap_read_page_bch(struct mtd_info *mtd, struct nand_chip *chip,
+				uint8_t *buf, int oob_required, int page)
+{
+	uint8_t *ecc_calc = chip->ecc.calc_buf;
+	uint8_t *ecc_code = chip->ecc.code_buf;
+	int stat, ret;
+	unsigned int max_bitflips = 0;
+
+	nand_read_page_op(chip, page, 0, NULL, 0);
+
+	/* Enable GPMC ecc engine */
+	chip->ecc.hwctl(mtd, NAND_ECC_READ);
+
+	/* Read data */
+	chip->read_buf(mtd, buf, mtd->writesize);
+
+	/* Read oob bytes */
+	nand_change_read_column_op(chip,
+				   mtd->writesize + BADBLOCK_MARKER_LENGTH,
+				   chip->oob_poi + BADBLOCK_MARKER_LENGTH,
+				   chip->ecc.total, false);
+
+	/* Calculate ecc bytes */
+	omap_calculate_ecc_bch_multi(mtd, buf, ecc_calc);
+
+	ret = mtd_ooblayout_get_eccbytes(mtd, ecc_code, chip->oob_poi, 0,
+					 chip->ecc.total);
+	if (ret)
+		return ret;
+
+	stat = chip->ecc.correct(mtd, buf, ecc_code, ecc_calc);
+
+	if (stat < 0) {
+		mtd->ecc_stats.failed++;
+	} else {
+		mtd->ecc_stats.corrected += stat;
+		max_bitflips = max_t(unsigned int, max_bitflips, stat);
+	}
+
+	return max_bitflips;
+}
+
+/**
+ * is_elm_present - checks for presence of ELM module by scanning DT nodes
+ * @omap_nand_info: NAND device structure containing platform data
+ */
+static bool is_elm_present(struct omap_nand_info *info,
+			   struct device_node *elm_node)
+{
+	struct platform_device *pdev;
+
+	/* check whether elm-id is passed via DT */
+	if (!elm_node) {
+		dev_err(&info->pdev->dev, "ELM devicetree node not found\n");
+		return false;
+	}
+	pdev = of_find_device_by_node(elm_node);
+	/* check whether ELM device is registered */
+	if (!pdev) {
+		dev_err(&info->pdev->dev, "ELM device not found\n");
+		return false;
+	}
+	/* ELM module available, now configure it */
+	info->elm_dev = &pdev->dev;
+	return true;
+}
+
+static bool omap2_nand_ecc_check(struct omap_nand_info *info)
+{
+	bool ecc_needs_bch, ecc_needs_omap_bch, ecc_needs_elm;
+
+	switch (info->ecc_opt) {
+	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
+	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
+		ecc_needs_omap_bch = false;
+		ecc_needs_bch = true;
+		ecc_needs_elm = false;
+		break;
+	case OMAP_ECC_BCH4_CODE_HW:
+	case OMAP_ECC_BCH8_CODE_HW:
+	case OMAP_ECC_BCH16_CODE_HW:
+		ecc_needs_omap_bch = true;
+		ecc_needs_bch = false;
+		ecc_needs_elm = true;
+		break;
+	default:
+		ecc_needs_omap_bch = false;
+		ecc_needs_bch = false;
+		ecc_needs_elm = false;
+		break;
+	}
+
+	if (ecc_needs_bch && !IS_ENABLED(CONFIG_MTD_NAND_ECC_BCH)) {
+		dev_err(&info->pdev->dev,
+			"CONFIG_MTD_NAND_ECC_BCH not enabled\n");
+		return false;
+	}
+	if (ecc_needs_omap_bch && !IS_ENABLED(CONFIG_MTD_NAND_OMAP_BCH)) {
+		dev_err(&info->pdev->dev,
+			"CONFIG_MTD_NAND_OMAP_BCH not enabled\n");
+		return false;
+	}
+	if (ecc_needs_elm && !is_elm_present(info, info->elm_of_node)) {
+		dev_err(&info->pdev->dev, "ELM not available\n");
+		return false;
+	}
+
+	return true;
+}
+
+static const char * const nand_xfer_types[] = {
+	[NAND_OMAP_PREFETCH_POLLED] = "prefetch-polled",
+	[NAND_OMAP_POLLED] = "polled",
+	[NAND_OMAP_PREFETCH_DMA] = "prefetch-dma",
+	[NAND_OMAP_PREFETCH_IRQ] = "prefetch-irq",
+};
+
+static int omap_get_dt_info(struct device *dev, struct omap_nand_info *info)
+{
+	struct device_node *child = dev->of_node;
+	int i;
+	const char *s;
+	u32 cs;
+
+	if (of_property_read_u32(child, "reg", &cs) < 0) {
+		dev_err(dev, "reg not found in DT\n");
+		return -EINVAL;
+	}
+
+	info->gpmc_cs = cs;
+
+	/* detect availability of ELM module. Won't be present pre-OMAP4 */
+	info->elm_of_node = of_parse_phandle(child, "ti,elm-id", 0);
+	if (!info->elm_of_node) {
+		info->elm_of_node = of_parse_phandle(child, "elm_id", 0);
+		if (!info->elm_of_node)
+			dev_dbg(dev, "ti,elm-id not in DT\n");
+	}
+
+	/* select ecc-scheme for NAND */
+	if (of_property_read_string(child, "ti,nand-ecc-opt", &s)) {
+		dev_err(dev, "ti,nand-ecc-opt not found\n");
+		return -EINVAL;
+	}
+
+	if (!strcmp(s, "sw")) {
+		info->ecc_opt = OMAP_ECC_HAM1_CODE_SW;
+	} else if (!strcmp(s, "ham1") ||
+		   !strcmp(s, "hw") || !strcmp(s, "hw-romcode")) {
+		info->ecc_opt =	OMAP_ECC_HAM1_CODE_HW;
+	} else if (!strcmp(s, "bch4")) {
+		if (info->elm_of_node)
+			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW;
+		else
+			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW_DETECTION_SW;
+	} else if (!strcmp(s, "bch8")) {
+		if (info->elm_of_node)
+			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW;
+		else
+			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW_DETECTION_SW;
+	} else if (!strcmp(s, "bch16")) {
+		info->ecc_opt =	OMAP_ECC_BCH16_CODE_HW;
+	} else {
+		dev_err(dev, "unrecognized value for ti,nand-ecc-opt\n");
+		return -EINVAL;
+	}
+
+	/* select data transfer mode */
+	if (!of_property_read_string(child, "ti,nand-xfer-type", &s)) {
+		for (i = 0; i < ARRAY_SIZE(nand_xfer_types); i++) {
+			if (!strcasecmp(s, nand_xfer_types[i])) {
+				info->xfer_type = i;
+				return 0;
+			}
+		}
+
+		dev_err(dev, "unrecognized value for ti,nand-xfer-type\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int omap_ooblayout_ecc(struct mtd_info *mtd, int section,
+			      struct mtd_oob_region *oobregion)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	struct nand_chip *chip = &info->nand;
+	int off = BADBLOCK_MARKER_LENGTH;
+
+	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
+	    !(chip->options & NAND_BUSWIDTH_16))
+		off = 1;
+
+	if (section)
+		return -ERANGE;
+
+	oobregion->offset = off;
+	oobregion->length = chip->ecc.total;
+
+	return 0;
+}
+
+static int omap_ooblayout_free(struct mtd_info *mtd, int section,
+			       struct mtd_oob_region *oobregion)
+{
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	struct nand_chip *chip = &info->nand;
+	int off = BADBLOCK_MARKER_LENGTH;
+
+	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
+	    !(chip->options & NAND_BUSWIDTH_16))
+		off = 1;
+
+	if (section)
+		return -ERANGE;
+
+	off += chip->ecc.total;
+	if (off >= mtd->oobsize)
+		return -ERANGE;
+
+	oobregion->offset = off;
+	oobregion->length = mtd->oobsize - off;
+
+	return 0;
+}
+
+static const struct mtd_ooblayout_ops omap_ooblayout_ops = {
+	.ecc = omap_ooblayout_ecc,
+	.free = omap_ooblayout_free,
+};
+
+static int omap_sw_ooblayout_ecc(struct mtd_info *mtd, int section,
+				 struct mtd_oob_region *oobregion)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	int off = BADBLOCK_MARKER_LENGTH;
+
+	if (section >= chip->ecc.steps)
+		return -ERANGE;
+
+	/*
+	 * When SW correction is employed, one OMAP specific marker byte is
+	 * reserved after each ECC step.
+	 */
+	oobregion->offset = off + (section * (chip->ecc.bytes + 1));
+	oobregion->length = chip->ecc.bytes;
+
+	return 0;
+}
+
+static int omap_sw_ooblayout_free(struct mtd_info *mtd, int section,
+				  struct mtd_oob_region *oobregion)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	int off = BADBLOCK_MARKER_LENGTH;
+
+	if (section)
+		return -ERANGE;
+
+	/*
+	 * When SW correction is employed, one OMAP specific marker byte is
+	 * reserved after each ECC step.
+	 */
+	off += ((chip->ecc.bytes + 1) * chip->ecc.steps);
+	if (off >= mtd->oobsize)
+		return -ERANGE;
+
+	oobregion->offset = off;
+	oobregion->length = mtd->oobsize - off;
+
+	return 0;
+}
+
+static const struct mtd_ooblayout_ops omap_sw_ooblayout_ops = {
+	.ecc = omap_sw_ooblayout_ecc,
+	.free = omap_sw_ooblayout_free,
+};
+
+static int omap_nand_attach_chip(struct nand_chip *chip)
+{
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	struct device *dev = &info->pdev->dev;
+	int min_oobbytes = BADBLOCK_MARKER_LENGTH;
+	int oobbytes_per_step;
+	dma_cap_mask_t mask;
+	int err;
+
+	if (chip->bbt_options & NAND_BBT_USE_FLASH)
+		chip->bbt_options |= NAND_BBT_NO_OOB;
+	else
+		chip->options |= NAND_SKIP_BBTSCAN;
+
+	/* Re-populate low-level callbacks based on xfer modes */
+	switch (info->xfer_type) {
+	case NAND_OMAP_PREFETCH_POLLED:
+		chip->read_buf = omap_read_buf_pref;
+		chip->write_buf = omap_write_buf_pref;
+		break;
+
+	case NAND_OMAP_POLLED:
+		/* Use nand_base defaults for {read,write}_buf */
+		break;
+
+	case NAND_OMAP_PREFETCH_DMA:
+		dma_cap_zero(mask);
+		dma_cap_set(DMA_SLAVE, mask);
+		info->dma = dma_request_chan(dev->parent, "rxtx");
+
+		if (IS_ERR(info->dma)) {
+			dev_err(dev, "DMA engine request failed\n");
+			return PTR_ERR(info->dma);
+		} else {
+			struct dma_slave_config cfg;
+
+			memset(&cfg, 0, sizeof(cfg));
+			cfg.src_addr = info->phys_base;
+			cfg.dst_addr = info->phys_base;
+			cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+			cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+			cfg.src_maxburst = 16;
+			cfg.dst_maxburst = 16;
+			err = dmaengine_slave_config(info->dma, &cfg);
+			if (err) {
+				dev_err(dev,
+					"DMA engine slave config failed: %d\n",
+					err);
+				return err;
+			}
+			chip->read_buf = omap_read_buf_dma_pref;
+			chip->write_buf = omap_write_buf_dma_pref;
+		}
+		break;
+
+	case NAND_OMAP_PREFETCH_IRQ:
+		info->gpmc_irq_fifo = platform_get_irq(info->pdev, 0);
+		if (info->gpmc_irq_fifo <= 0) {
+			dev_err(dev, "Error getting fifo IRQ\n");
+			return -ENODEV;
+		}
+		err = devm_request_irq(dev, info->gpmc_irq_fifo,
+				       omap_nand_irq, IRQF_SHARED,
+				       "gpmc-nand-fifo", info);
+		if (err) {
+			dev_err(dev, "Requesting IRQ %d, error %d\n",
+				info->gpmc_irq_fifo, err);
+			info->gpmc_irq_fifo = 0;
+			return err;
+		}
+
+		info->gpmc_irq_count = platform_get_irq(info->pdev, 1);
+		if (info->gpmc_irq_count <= 0) {
+			dev_err(dev, "Error getting IRQ count\n");
+			return -ENODEV;
+		}
+		err = devm_request_irq(dev, info->gpmc_irq_count,
+				       omap_nand_irq, IRQF_SHARED,
+				       "gpmc-nand-count", info);
+		if (err) {
+			dev_err(dev, "Requesting IRQ %d, error %d\n",
+				info->gpmc_irq_count, err);
+			info->gpmc_irq_count = 0;
+			return err;
+		}
+
+		chip->read_buf = omap_read_buf_irq_pref;
+		chip->write_buf = omap_write_buf_irq_pref;
+
+		break;
+
+	default:
+		dev_err(dev, "xfer_type %d not supported!\n", info->xfer_type);
+		return -EINVAL;
+	}
+
+	if (!omap2_nand_ecc_check(info))
+		return -EINVAL;
+
+	/*
+	 * Bail out earlier to let NAND_ECC_SOFT code create its own
+	 * ooblayout instead of using ours.
+	 */
+	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_SW) {
+		chip->ecc.mode = NAND_ECC_SOFT;
+		chip->ecc.algo = NAND_ECC_HAMMING;
+		return 0;
+	}
+
+	/* Populate MTD interface based on ECC scheme */
+	switch (info->ecc_opt) {
+	case OMAP_ECC_HAM1_CODE_HW:
+		dev_info(dev, "nand: using OMAP_ECC_HAM1_CODE_HW\n");
+		chip->ecc.mode		= NAND_ECC_HW;
+		chip->ecc.bytes		= 3;
+		chip->ecc.size		= 512;
+		chip->ecc.strength	= 1;
+		chip->ecc.calculate	= omap_calculate_ecc;
+		chip->ecc.hwctl		= omap_enable_hwecc;
+		chip->ecc.correct	= omap_correct_data;
+		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
+		oobbytes_per_step	= chip->ecc.bytes;
+
+		if (!(chip->options & NAND_BUSWIDTH_16))
+			min_oobbytes	= 1;
+
+		break;
+
+	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
+		pr_info("nand: using OMAP_ECC_BCH4_CODE_HW_DETECTION_SW\n");
+		chip->ecc.mode		= NAND_ECC_HW;
+		chip->ecc.size		= 512;
+		chip->ecc.bytes		= 7;
+		chip->ecc.strength	= 4;
+		chip->ecc.hwctl		= omap_enable_hwecc_bch;
+		chip->ecc.correct	= nand_bch_correct_data;
+		chip->ecc.calculate	= omap_calculate_ecc_bch_sw;
+		mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
+		/* Reserve one byte for the OMAP marker */
+		oobbytes_per_step	= chip->ecc.bytes + 1;
+		/* Software BCH library is used for locating errors */
+		chip->ecc.priv		= nand_bch_init(mtd);
+		if (!chip->ecc.priv) {
+			dev_err(dev, "Unable to use BCH library\n");
+			return -EINVAL;
+		}
+		break;
+
+	case OMAP_ECC_BCH4_CODE_HW:
+		pr_info("nand: using OMAP_ECC_BCH4_CODE_HW ECC scheme\n");
+		chip->ecc.mode		= NAND_ECC_HW;
+		chip->ecc.size		= 512;
+		/* 14th bit is kept reserved for ROM-code compatibility */
+		chip->ecc.bytes		= 7 + 1;
+		chip->ecc.strength	= 4;
+		chip->ecc.hwctl		= omap_enable_hwecc_bch;
+		chip->ecc.correct	= omap_elm_correct_data;
+		chip->ecc.read_page	= omap_read_page_bch;
+		chip->ecc.write_page	= omap_write_page_bch;
+		chip->ecc.write_subpage	= omap_write_subpage_bch;
+		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
+		oobbytes_per_step	= chip->ecc.bytes;
+
+		err = elm_config(info->elm_dev, BCH4_ECC,
+				 mtd->writesize / chip->ecc.size,
+				 chip->ecc.size, chip->ecc.bytes);
+		if (err < 0)
+			return err;
+		break;
+
+	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
+		pr_info("nand: using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW\n");
+		chip->ecc.mode		= NAND_ECC_HW;
+		chip->ecc.size		= 512;
+		chip->ecc.bytes		= 13;
+		chip->ecc.strength	= 8;
+		chip->ecc.hwctl		= omap_enable_hwecc_bch;
+		chip->ecc.correct	= nand_bch_correct_data;
+		chip->ecc.calculate	= omap_calculate_ecc_bch_sw;
+		mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
+		/* Reserve one byte for the OMAP marker */
+		oobbytes_per_step	= chip->ecc.bytes + 1;
+		/* Software BCH library is used for locating errors */
+		chip->ecc.priv		= nand_bch_init(mtd);
+		if (!chip->ecc.priv) {
+			dev_err(dev, "unable to use BCH library\n");
+			return -EINVAL;
+		}
+		break;
+
+	case OMAP_ECC_BCH8_CODE_HW:
+		pr_info("nand: using OMAP_ECC_BCH8_CODE_HW ECC scheme\n");
+		chip->ecc.mode		= NAND_ECC_HW;
+		chip->ecc.size		= 512;
+		/* 14th bit is kept reserved for ROM-code compatibility */
+		chip->ecc.bytes		= 13 + 1;
+		chip->ecc.strength	= 8;
+		chip->ecc.hwctl		= omap_enable_hwecc_bch;
+		chip->ecc.correct	= omap_elm_correct_data;
+		chip->ecc.read_page	= omap_read_page_bch;
+		chip->ecc.write_page	= omap_write_page_bch;
+		chip->ecc.write_subpage	= omap_write_subpage_bch;
+		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
+		oobbytes_per_step	= chip->ecc.bytes;
+
+		err = elm_config(info->elm_dev, BCH8_ECC,
+				 mtd->writesize / chip->ecc.size,
+				 chip->ecc.size, chip->ecc.bytes);
+		if (err < 0)
+			return err;
+
+		break;
+
+	case OMAP_ECC_BCH16_CODE_HW:
+		pr_info("Using OMAP_ECC_BCH16_CODE_HW ECC scheme\n");
+		chip->ecc.mode		= NAND_ECC_HW;
+		chip->ecc.size		= 512;
+		chip->ecc.bytes		= 26;
+		chip->ecc.strength	= 16;
+		chip->ecc.hwctl		= omap_enable_hwecc_bch;
+		chip->ecc.correct	= omap_elm_correct_data;
+		chip->ecc.read_page	= omap_read_page_bch;
+		chip->ecc.write_page	= omap_write_page_bch;
+		chip->ecc.write_subpage	= omap_write_subpage_bch;
+		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
+		oobbytes_per_step	= chip->ecc.bytes;
+
+		err = elm_config(info->elm_dev, BCH16_ECC,
+				 mtd->writesize / chip->ecc.size,
+				 chip->ecc.size, chip->ecc.bytes);
+		if (err < 0)
+			return err;
+
+		break;
+	default:
+		dev_err(dev, "Invalid or unsupported ECC scheme\n");
+		return -EINVAL;
+	}
+
+	/* Check if NAND device's OOB is enough to store ECC signatures */
+	min_oobbytes += (oobbytes_per_step *
+			 (mtd->writesize / chip->ecc.size));
+	if (mtd->oobsize < min_oobbytes) {
+		dev_err(dev,
+			"Not enough OOB bytes: required = %d, available=%d\n",
+			min_oobbytes, mtd->oobsize);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct nand_controller_ops omap_nand_controller_ops = {
+	.attach_chip = omap_nand_attach_chip,
+};
+
+/* Shared among all NAND instances to synchronize access to the ECC Engine */
+static struct nand_controller omap_gpmc_controller = {
+	.lock = __SPIN_LOCK_UNLOCKED(omap_gpmc_controller.lock),
+	.wq = __WAIT_QUEUE_HEAD_INITIALIZER(omap_gpmc_controller.wq),
+	.ops = &omap_nand_controller_ops,
+};
+
+static int omap_nand_probe(struct platform_device *pdev)
+{
+	struct omap_nand_info		*info;
+	struct mtd_info			*mtd;
+	struct nand_chip		*nand_chip;
+	int				err;
+	struct resource			*res;
+	struct device			*dev = &pdev->dev;
+
+	info = devm_kzalloc(&pdev->dev, sizeof(struct omap_nand_info),
+				GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->pdev = pdev;
+
+	err = omap_get_dt_info(dev, info);
+	if (err)
+		return err;
+
+	info->ops = gpmc_omap_get_nand_ops(&info->reg, info->gpmc_cs);
+	if (!info->ops) {
+		dev_err(&pdev->dev, "Failed to get GPMC->NAND interface\n");
+		return -ENODEV;
+	}
+
+	nand_chip		= &info->nand;
+	mtd			= nand_to_mtd(nand_chip);
+	mtd->dev.parent		= &pdev->dev;
+	nand_chip->ecc.priv	= NULL;
+	nand_set_flash_node(nand_chip, dev->of_node);
+
+	if (!mtd->name) {
+		mtd->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+					   "omap2-nand.%d", info->gpmc_cs);
+		if (!mtd->name) {
+			dev_err(&pdev->dev, "Failed to set MTD name\n");
+			return -ENOMEM;
+		}
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	nand_chip->IO_ADDR_R = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(nand_chip->IO_ADDR_R))
+		return PTR_ERR(nand_chip->IO_ADDR_R);
+
+	info->phys_base = res->start;
+
+	nand_chip->controller = &omap_gpmc_controller;
+
+	nand_chip->IO_ADDR_W = nand_chip->IO_ADDR_R;
+	nand_chip->cmd_ctrl  = omap_hwcontrol;
+
+	info->ready_gpiod = devm_gpiod_get_optional(&pdev->dev, "rb",
+						    GPIOD_IN);
+	if (IS_ERR(info->ready_gpiod)) {
+		dev_err(dev, "failed to get ready gpio\n");
+		return PTR_ERR(info->ready_gpiod);
+	}
+
+	/*
+	 * If RDY/BSY line is connected to OMAP then use the omap ready
+	 * function and the generic nand_wait function which reads the status
+	 * register after monitoring the RDY/BSY line. Otherwise use a standard
+	 * chip delay which is slightly more than tR (AC Timing) of the NAND
+	 * device and read status register until you get a failure or success
+	 */
+	if (info->ready_gpiod) {
+		nand_chip->dev_ready = omap_dev_ready;
+		nand_chip->chip_delay = 0;
+	} else {
+		nand_chip->waitfunc = omap_wait;
+		nand_chip->chip_delay = 50;
+	}
+
+	if (info->flash_bbt)
+		nand_chip->bbt_options |= NAND_BBT_USE_FLASH;
+
+	/* scan NAND device connected to chip controller */
+	nand_chip->options |= info->devsize & NAND_BUSWIDTH_16;
+
+	err = nand_scan(nand_chip, 1);
+	if (err)
+		goto return_error;
+
+	err = mtd_device_register(mtd, NULL, 0);
+	if (err)
+		goto cleanup_nand;
+
+	platform_set_drvdata(pdev, mtd);
+
+	return 0;
+
+cleanup_nand:
+	nand_cleanup(nand_chip);
+
+return_error:
+	if (!IS_ERR_OR_NULL(info->dma))
+		dma_release_channel(info->dma);
+	if (nand_chip->ecc.priv) {
+		nand_bch_free(nand_chip->ecc.priv);
+		nand_chip->ecc.priv = NULL;
+	}
+	return err;
+}
+
+static int omap_nand_remove(struct platform_device *pdev)
+{
+	struct mtd_info *mtd = platform_get_drvdata(pdev);
+	struct nand_chip *nand_chip = mtd_to_nand(mtd);
+	struct omap_nand_info *info = mtd_to_omap(mtd);
+	if (nand_chip->ecc.priv) {
+		nand_bch_free(nand_chip->ecc.priv);
+		nand_chip->ecc.priv = NULL;
+	}
+	if (info->dma)
+		dma_release_channel(info->dma);
+	nand_release(nand_chip);
+	return 0;
+}
+
+static const struct of_device_id omap_nand_ids[] = {
+	{ .compatible = "ti,omap2-nand", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, omap_nand_ids);
+
+static struct platform_driver omap_nand_driver = {
+	.probe		= omap_nand_probe,
+	.remove		= omap_nand_remove,
+	.driver		= {
+		.name	= DRIVER_NAME,
+		.of_match_table = of_match_ptr(omap_nand_ids),
+	},
+};
+
+module_platform_driver(omap_nand_driver);
+
+MODULE_ALIAS("platform:" DRIVER_NAME);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Glue layer for NAND flash on TI OMAP boards");