Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / mtd / nand / omap2.c
diff --git a/kernel/drivers/mtd/nand/omap2.c b/kernel/drivers/mtd/nand/omap2.c
new file mode 100644 (file)
index 0000000..60fa899
--- /dev/null
@@ -0,0 +1,2086 @@
+/*
+ * 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/module.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/sched.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.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/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 OMAP24XX_DMA_GPMC              4
+
+#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};
+
+/* Shared among all NAND instances to synchronize access to the ECC Engine */
+static struct nand_hw_control omap_gpmc_controller = {
+       .lock = __SPIN_LOCK_UNLOCKED(omap_gpmc_controller.lock),
+       .wq = __WAIT_QUEUE_HEAD_INITIALIZER(omap_gpmc_controller.wq),
+};
+
+struct omap_nand_info {
+       struct omap_nand_platform_data  *pdata;
+       struct mtd_info                 mtd;
+       struct nand_chip                nand;
+       struct platform_device          *pdev;
+
+       int                             gpmc_cs;
+       unsigned long                   phys_base;
+       enum omap_ecc                   ecc_opt;
+       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;
+       struct gpmc_nand_regs           reg;
+       /* generated at runtime depending on ECC algorithm and layout selected */
+       struct nand_ecclayout           oobinfo;
+       /* fields specific for BCHx_HW ECC scheme */
+       struct device                   *elm_dev;
+       struct device_node              *of_node;
+};
+
+/**
+ * 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) | (0x1 & is_write));
+       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 = container_of(mtd,
+                                       struct omap_nand_info, 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->priv;
+
+       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 = container_of(mtd,
+                                               struct omap_nand_info, mtd);
+       u_char *p = (u_char *)buf;
+       u32     status = 0;
+
+       while (len--) {
+               iowrite8(*p++, info->nand.IO_ADDR_W);
+               /* wait until buffer is available for write */
+               do {
+                       status = readl(info->reg.gpmc_status) &
+                                       STATUS_BUFF_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->priv;
+
+       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 = container_of(mtd,
+                                               struct omap_nand_info, mtd);
+       u16 *p = (u16 *) buf;
+       u32     status = 0;
+       /* 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 = readl(info->reg.gpmc_status) &
+                                       STATUS_BUFF_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 = container_of(mtd,
+                                               struct omap_nand_info, 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 = container_of(mtd,
+                                               struct omap_nand_info, 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 = container_of(mtd,
+                                       struct omap_nand_info, 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 (addr >= high_memory) {
+               struct page *p1;
+
+               if (((size_t)addr & PAGE_MASK) !=
+                       ((size_t)(addr + len - 1) & PAGE_MASK))
+                       goto out_copy;
+               p1 = vmalloc_to_page(addr);
+               if (!p1)
+                       goto out_copy;
+               addr = page_address(p1) + ((size_t)addr & ~PAGE_MASK);
+       }
+
+       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);
+
+       /*  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;
+
+       init_completion(&info->comp);
+       dma_async_issue_pending(info->dma);
+
+       /* setup and start DMA using dma_addr */
+       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 = container_of(mtd,
+                                               struct omap_nand_info, 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 = container_of(mtd,
+                                               struct omap_nand_info, 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 -1;
+
+       case 11:
+               /* UN-Correctable error */
+               pr_debug("ECC UNCORRECTED_ERROR B\n");
+               return -1;
+
+       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 -1;
+       }
+}
+
+/**
+ * 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 = container_of(mtd, struct omap_nand_info,
+                                                       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 = container_of(mtd, struct omap_nand_info,
+                                                       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 = container_of(mtd, struct omap_nand_info,
+                                                       mtd);
+       struct nand_chip *chip = mtd->priv;
+       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->priv;
+       struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
+                                                       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 - calls the platform specific dev_ready function
+ * @mtd: MTD device structure
+ */
+static int omap_dev_ready(struct mtd_info *mtd)
+{
+       unsigned int val = 0;
+       struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
+                                                       mtd);
+
+       val = readl(info->reg.gpmc_status);
+
+       if ((val & 0x100) == 0x100) {
+               return 1;
+       } else {
+               return 0;
+       }
+}
+
+/**
+ * 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 = container_of(mtd, struct omap_nand_info,
+                                                  mtd);
+       enum omap_ecc ecc_opt = info->ecc_opt;
+       struct nand_chip *chip = mtd->priv;
+       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 bytes of ECC bytes
+ * @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 ecc vectors for the page
+ */
+static int __maybe_unused omap_calculate_ecc_bch(struct mtd_info *mtd,
+                                       const u_char *dat, u_char *ecc_calc)
+{
+       struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
+                                                  mtd);
+       int eccbytes    = info->nand.ecc.bytes;
+       struct gpmc_nand_regs   *gpmc_regs = &info->reg;
+       u8 *ecc_code;
+       unsigned long nsectors, bch_val1, bch_val2, bch_val3, bch_val4;
+       u32 val;
+       int i, j;
+
+       nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
+       for (i = 0; i < nsectors; i++) {
+               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;
+               }
+
+       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 = container_of(mtd, struct omap_nand_info,
+                       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
+ *
+ * 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 i;
+       uint8_t *ecc_calc = chip->buffers->ecccalc;
+       uint32_t *eccpos = chip->ecc.layout->eccpos;
+
+       /* 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 */
+       chip->ecc.calculate(mtd, buf, &ecc_calc[0]);
+
+       for (i = 0; i < chip->ecc.total; i++)
+               chip->oob_poi[eccpos[i]] = ecc_calc[i];
+
+       /* Write ecc vector to OOB area */
+       chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
+       return 0;
+}
+
+/**
+ * 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->buffers->ecccalc;
+       uint8_t *ecc_code = chip->buffers->ecccode;
+       uint32_t *eccpos = chip->ecc.layout->eccpos;
+       uint8_t *oob = &chip->oob_poi[eccpos[0]];
+       uint32_t oob_pos = mtd->writesize + chip->ecc.layout->eccpos[0];
+       int stat;
+       unsigned int max_bitflips = 0;
+
+       /* Enable GPMC ecc engine */
+       chip->ecc.hwctl(mtd, NAND_ECC_READ);
+
+       /* Read data */
+       chip->read_buf(mtd, buf, mtd->writesize);
+
+       /* Read oob bytes */
+       chip->cmdfunc(mtd, NAND_CMD_RNDOUT, oob_pos, -1);
+       chip->read_buf(mtd, oob, chip->ecc.total);
+
+       /* Calculate ecc bytes */
+       chip->ecc.calculate(mtd, buf, ecc_calc);
+
+       memcpy(ecc_code, &chip->oob_poi[eccpos[0]], chip->ecc.total);
+
+       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,
+                                struct omap_nand_platform_data *pdata)
+{
+       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, pdata->elm_of_node)) {
+               dev_err(&info->pdev->dev, "ELM not available\n");
+               return false;
+       }
+
+       return true;
+}
+
+static int omap_nand_probe(struct platform_device *pdev)
+{
+       struct omap_nand_info           *info;
+       struct omap_nand_platform_data  *pdata;
+       struct mtd_info                 *mtd;
+       struct nand_chip                *nand_chip;
+       struct nand_ecclayout           *ecclayout;
+       int                             err;
+       int                             i;
+       dma_cap_mask_t                  mask;
+       unsigned                        sig;
+       unsigned                        oob_index;
+       struct resource                 *res;
+       struct mtd_part_parser_data     ppdata = {};
+
+       pdata = dev_get_platdata(&pdev->dev);
+       if (pdata == NULL) {
+               dev_err(&pdev->dev, "platform data missing\n");
+               return -ENODEV;
+       }
+
+       info = devm_kzalloc(&pdev->dev, sizeof(struct omap_nand_info),
+                               GFP_KERNEL);
+       if (!info)
+               return -ENOMEM;
+
+       platform_set_drvdata(pdev, info);
+
+       info->pdev              = pdev;
+       info->gpmc_cs           = pdata->cs;
+       info->reg               = pdata->reg;
+       info->of_node           = pdata->of_node;
+       info->ecc_opt           = pdata->ecc_opt;
+       mtd                     = &info->mtd;
+       mtd->priv               = &info->nand;
+       mtd->name               = dev_name(&pdev->dev);
+       mtd->owner              = THIS_MODULE;
+       nand_chip               = &info->nand;
+       nand_chip->ecc.priv     = NULL;
+
+       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;
+
+       /*
+        * 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 (pdata->dev_ready) {
+               nand_chip->dev_ready = omap_dev_ready;
+               nand_chip->chip_delay = 0;
+       } else {
+               nand_chip->waitfunc = omap_wait;
+               nand_chip->chip_delay = 50;
+       }
+
+       if (pdata->flash_bbt)
+               nand_chip->bbt_options |= NAND_BBT_USE_FLASH | NAND_BBT_NO_OOB;
+       else
+               nand_chip->options |= NAND_SKIP_BBTSCAN;
+
+       /* scan NAND device connected to chip controller */
+       nand_chip->options |= pdata->devsize & NAND_BUSWIDTH_16;
+       if (nand_scan_ident(mtd, 1, NULL)) {
+               dev_err(&info->pdev->dev, "scan failed, may be bus-width mismatch\n");
+               err = -ENXIO;
+               goto return_error;
+       }
+
+       /* re-populate low-level callbacks based on xfer modes */
+       switch (pdata->xfer_type) {
+       case NAND_OMAP_PREFETCH_POLLED:
+               nand_chip->read_buf   = omap_read_buf_pref;
+               nand_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);
+               sig = OMAP24XX_DMA_GPMC;
+               info->dma = dma_request_channel(mask, omap_dma_filter_fn, &sig);
+               if (!info->dma) {
+                       dev_err(&pdev->dev, "DMA engine request failed\n");
+                       err = -ENXIO;
+                       goto return_error;
+               } 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(&pdev->dev, "DMA engine slave config failed: %d\n",
+                                       err);
+                               goto return_error;
+                       }
+                       nand_chip->read_buf   = omap_read_buf_dma_pref;
+                       nand_chip->write_buf  = omap_write_buf_dma_pref;
+               }
+               break;
+
+       case NAND_OMAP_PREFETCH_IRQ:
+               info->gpmc_irq_fifo = platform_get_irq(pdev, 0);
+               if (info->gpmc_irq_fifo <= 0) {
+                       dev_err(&pdev->dev, "error getting fifo irq\n");
+                       err = -ENODEV;
+                       goto return_error;
+               }
+               err = devm_request_irq(&pdev->dev, info->gpmc_irq_fifo,
+                                       omap_nand_irq, IRQF_SHARED,
+                                       "gpmc-nand-fifo", info);
+               if (err) {
+                       dev_err(&pdev->dev, "requesting irq(%d) error:%d",
+                                               info->gpmc_irq_fifo, err);
+                       info->gpmc_irq_fifo = 0;
+                       goto return_error;
+               }
+
+               info->gpmc_irq_count = platform_get_irq(pdev, 1);
+               if (info->gpmc_irq_count <= 0) {
+                       dev_err(&pdev->dev, "error getting count irq\n");
+                       err = -ENODEV;
+                       goto return_error;
+               }
+               err = devm_request_irq(&pdev->dev, info->gpmc_irq_count,
+                                       omap_nand_irq, IRQF_SHARED,
+                                       "gpmc-nand-count", info);
+               if (err) {
+                       dev_err(&pdev->dev, "requesting irq(%d) error:%d",
+                                               info->gpmc_irq_count, err);
+                       info->gpmc_irq_count = 0;
+                       goto return_error;
+               }
+
+               nand_chip->read_buf  = omap_read_buf_irq_pref;
+               nand_chip->write_buf = omap_write_buf_irq_pref;
+
+               break;
+
+       default:
+               dev_err(&pdev->dev,
+                       "xfer_type(%d) not supported!\n", pdata->xfer_type);
+               err = -EINVAL;
+               goto return_error;
+       }
+
+       if (!omap2_nand_ecc_check(info, pdata)) {
+               err = -EINVAL;
+               goto return_error;
+       }
+
+       /* populate MTD interface based on ECC scheme */
+       ecclayout               = &info->oobinfo;
+       switch (info->ecc_opt) {
+       case OMAP_ECC_HAM1_CODE_SW:
+               nand_chip->ecc.mode = NAND_ECC_SOFT;
+               break;
+
+       case OMAP_ECC_HAM1_CODE_HW:
+               pr_info("nand: using OMAP_ECC_HAM1_CODE_HW\n");
+               nand_chip->ecc.mode             = NAND_ECC_HW;
+               nand_chip->ecc.bytes            = 3;
+               nand_chip->ecc.size             = 512;
+               nand_chip->ecc.strength         = 1;
+               nand_chip->ecc.calculate        = omap_calculate_ecc;
+               nand_chip->ecc.hwctl            = omap_enable_hwecc;
+               nand_chip->ecc.correct          = omap_correct_data;
+               /* define ECC layout */
+               ecclayout->eccbytes             = nand_chip->ecc.bytes *
+                                                       (mtd->writesize /
+                                                       nand_chip->ecc.size);
+               if (nand_chip->options & NAND_BUSWIDTH_16)
+                       oob_index               = BADBLOCK_MARKER_LENGTH;
+               else
+                       oob_index               = 1;
+               for (i = 0; i < ecclayout->eccbytes; i++, oob_index++)
+                       ecclayout->eccpos[i]    = oob_index;
+               /* no reserved-marker in ecclayout for this ecc-scheme */
+               ecclayout->oobfree->offset      =
+                               ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
+               break;
+
+       case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
+               pr_info("nand: using OMAP_ECC_BCH4_CODE_HW_DETECTION_SW\n");
+               nand_chip->ecc.mode             = NAND_ECC_HW;
+               nand_chip->ecc.size             = 512;
+               nand_chip->ecc.bytes            = 7;
+               nand_chip->ecc.strength         = 4;
+               nand_chip->ecc.hwctl            = omap_enable_hwecc_bch;
+               nand_chip->ecc.correct          = nand_bch_correct_data;
+               nand_chip->ecc.calculate        = omap_calculate_ecc_bch;
+               /* define ECC layout */
+               ecclayout->eccbytes             = nand_chip->ecc.bytes *
+                                                       (mtd->writesize /
+                                                       nand_chip->ecc.size);
+               oob_index                       = BADBLOCK_MARKER_LENGTH;
+               for (i = 0; i < ecclayout->eccbytes; i++, oob_index++) {
+                       ecclayout->eccpos[i] = oob_index;
+                       if (((i + 1) % nand_chip->ecc.bytes) == 0)
+                               oob_index++;
+               }
+               /* include reserved-marker in ecclayout->oobfree calculation */
+               ecclayout->oobfree->offset      = 1 +
+                               ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
+               /* software bch library is used for locating errors */
+               nand_chip->ecc.priv             = nand_bch_init(mtd,
+                                                       nand_chip->ecc.size,
+                                                       nand_chip->ecc.bytes,
+                                                       &ecclayout);
+               if (!nand_chip->ecc.priv) {
+                       dev_err(&info->pdev->dev, "unable to use BCH library\n");
+                       err = -EINVAL;
+                       goto return_error;
+               }
+               break;
+
+       case OMAP_ECC_BCH4_CODE_HW:
+               pr_info("nand: using OMAP_ECC_BCH4_CODE_HW ECC scheme\n");
+               nand_chip->ecc.mode             = NAND_ECC_HW;
+               nand_chip->ecc.size             = 512;
+               /* 14th bit is kept reserved for ROM-code compatibility */
+               nand_chip->ecc.bytes            = 7 + 1;
+               nand_chip->ecc.strength         = 4;
+               nand_chip->ecc.hwctl            = omap_enable_hwecc_bch;
+               nand_chip->ecc.correct          = omap_elm_correct_data;
+               nand_chip->ecc.calculate        = omap_calculate_ecc_bch;
+               nand_chip->ecc.read_page        = omap_read_page_bch;
+               nand_chip->ecc.write_page       = omap_write_page_bch;
+               /* define ECC layout */
+               ecclayout->eccbytes             = nand_chip->ecc.bytes *
+                                                       (mtd->writesize /
+                                                       nand_chip->ecc.size);
+               oob_index                       = BADBLOCK_MARKER_LENGTH;
+               for (i = 0; i < ecclayout->eccbytes; i++, oob_index++)
+                       ecclayout->eccpos[i]    = oob_index;
+               /* reserved marker already included in ecclayout->eccbytes */
+               ecclayout->oobfree->offset      =
+                               ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
+
+               err = elm_config(info->elm_dev, BCH4_ECC,
+                                info->mtd.writesize / nand_chip->ecc.size,
+                                nand_chip->ecc.size, nand_chip->ecc.bytes);
+               if (err < 0)
+                       goto return_error;
+               break;
+
+       case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
+               pr_info("nand: using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW\n");
+               nand_chip->ecc.mode             = NAND_ECC_HW;
+               nand_chip->ecc.size             = 512;
+               nand_chip->ecc.bytes            = 13;
+               nand_chip->ecc.strength         = 8;
+               nand_chip->ecc.hwctl            = omap_enable_hwecc_bch;
+               nand_chip->ecc.correct          = nand_bch_correct_data;
+               nand_chip->ecc.calculate        = omap_calculate_ecc_bch;
+               /* define ECC layout */
+               ecclayout->eccbytes             = nand_chip->ecc.bytes *
+                                                       (mtd->writesize /
+                                                       nand_chip->ecc.size);
+               oob_index                       = BADBLOCK_MARKER_LENGTH;
+               for (i = 0; i < ecclayout->eccbytes; i++, oob_index++) {
+                       ecclayout->eccpos[i] = oob_index;
+                       if (((i + 1) % nand_chip->ecc.bytes) == 0)
+                               oob_index++;
+               }
+               /* include reserved-marker in ecclayout->oobfree calculation */
+               ecclayout->oobfree->offset      = 1 +
+                               ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
+               /* software bch library is used for locating errors */
+               nand_chip->ecc.priv             = nand_bch_init(mtd,
+                                                       nand_chip->ecc.size,
+                                                       nand_chip->ecc.bytes,
+                                                       &ecclayout);
+               if (!nand_chip->ecc.priv) {
+                       dev_err(&info->pdev->dev, "unable to use BCH library\n");
+                       err = -EINVAL;
+                       goto return_error;
+               }
+               break;
+
+       case OMAP_ECC_BCH8_CODE_HW:
+               pr_info("nand: using OMAP_ECC_BCH8_CODE_HW ECC scheme\n");
+               nand_chip->ecc.mode             = NAND_ECC_HW;
+               nand_chip->ecc.size             = 512;
+               /* 14th bit is kept reserved for ROM-code compatibility */
+               nand_chip->ecc.bytes            = 13 + 1;
+               nand_chip->ecc.strength         = 8;
+               nand_chip->ecc.hwctl            = omap_enable_hwecc_bch;
+               nand_chip->ecc.correct          = omap_elm_correct_data;
+               nand_chip->ecc.calculate        = omap_calculate_ecc_bch;
+               nand_chip->ecc.read_page        = omap_read_page_bch;
+               nand_chip->ecc.write_page       = omap_write_page_bch;
+
+               err = elm_config(info->elm_dev, BCH8_ECC,
+                                info->mtd.writesize / nand_chip->ecc.size,
+                                nand_chip->ecc.size, nand_chip->ecc.bytes);
+               if (err < 0)
+                       goto return_error;
+
+               /* define ECC layout */
+               ecclayout->eccbytes             = nand_chip->ecc.bytes *
+                                                       (mtd->writesize /
+                                                       nand_chip->ecc.size);
+               oob_index                       = BADBLOCK_MARKER_LENGTH;
+               for (i = 0; i < ecclayout->eccbytes; i++, oob_index++)
+                       ecclayout->eccpos[i]    = oob_index;
+               /* reserved marker already included in ecclayout->eccbytes */
+               ecclayout->oobfree->offset      =
+                               ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
+               break;
+
+       case OMAP_ECC_BCH16_CODE_HW:
+               pr_info("using OMAP_ECC_BCH16_CODE_HW ECC scheme\n");
+               nand_chip->ecc.mode             = NAND_ECC_HW;
+               nand_chip->ecc.size             = 512;
+               nand_chip->ecc.bytes            = 26;
+               nand_chip->ecc.strength         = 16;
+               nand_chip->ecc.hwctl            = omap_enable_hwecc_bch;
+               nand_chip->ecc.correct          = omap_elm_correct_data;
+               nand_chip->ecc.calculate        = omap_calculate_ecc_bch;
+               nand_chip->ecc.read_page        = omap_read_page_bch;
+               nand_chip->ecc.write_page       = omap_write_page_bch;
+
+               err = elm_config(info->elm_dev, BCH16_ECC,
+                                info->mtd.writesize / nand_chip->ecc.size,
+                                nand_chip->ecc.size, nand_chip->ecc.bytes);
+               if (err < 0)
+                       goto return_error;
+
+               /* define ECC layout */
+               ecclayout->eccbytes             = nand_chip->ecc.bytes *
+                                                       (mtd->writesize /
+                                                       nand_chip->ecc.size);
+               oob_index                       = BADBLOCK_MARKER_LENGTH;
+               for (i = 0; i < ecclayout->eccbytes; i++, oob_index++)
+                       ecclayout->eccpos[i]    = oob_index;
+               /* reserved marker already included in ecclayout->eccbytes */
+               ecclayout->oobfree->offset      =
+                               ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
+               break;
+       default:
+               dev_err(&info->pdev->dev, "invalid or unsupported ECC scheme\n");
+               err = -EINVAL;
+               goto return_error;
+       }
+
+       if (info->ecc_opt == OMAP_ECC_HAM1_CODE_SW)
+               goto scan_tail;
+
+       /* all OOB bytes from oobfree->offset till end off OOB are free */
+       ecclayout->oobfree->length = mtd->oobsize - ecclayout->oobfree->offset;
+       /* check if NAND device's OOB is enough to store ECC signatures */
+       if (mtd->oobsize < (ecclayout->eccbytes + BADBLOCK_MARKER_LENGTH)) {
+               dev_err(&info->pdev->dev,
+                       "not enough OOB bytes required = %d, available=%d\n",
+                       ecclayout->eccbytes, mtd->oobsize);
+               err = -EINVAL;
+               goto return_error;
+       }
+       nand_chip->ecc.layout = ecclayout;
+
+scan_tail:
+       /* second phase scan */
+       if (nand_scan_tail(mtd)) {
+               err = -ENXIO;
+               goto return_error;
+       }
+
+       ppdata.of_node = pdata->of_node;
+       mtd_device_parse_register(mtd, NULL, &ppdata, pdata->parts,
+                                 pdata->nr_parts);
+
+       platform_set_drvdata(pdev, mtd);
+
+       return 0;
+
+return_error:
+       if (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->priv;
+       struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
+                                                       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(mtd);
+       return 0;
+}
+
+static struct platform_driver omap_nand_driver = {
+       .probe          = omap_nand_probe,
+       .remove         = omap_nand_remove,
+       .driver         = {
+               .name   = DRIVER_NAME,
+       },
+};
+
+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");