Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / mtd / nand / atmel_nand.c
diff --git a/kernel/drivers/mtd/nand/atmel_nand.c b/kernel/drivers/mtd/nand/atmel_nand.c
new file mode 100644 (file)
index 0000000..46010bd
--- /dev/null
@@ -0,0 +1,2412 @@
+/*
+ *  Copyright © 2003 Rick Bronson
+ *
+ *  Derived from drivers/mtd/nand/autcpu12.c
+ *      Copyright © 2001 Thomas Gleixner (gleixner@autronix.de)
+ *
+ *  Derived from drivers/mtd/spia.c
+ *      Copyright © 2000 Steven J. Hill (sjhill@cotw.com)
+ *
+ *
+ *  Add Hardware ECC support for AT91SAM9260 / AT91SAM9263
+ *     Richard Genoud (richard.genoud@gmail.com), Adeneo Copyright © 2007
+ *
+ *     Derived from Das U-Boot source code
+ *                     (u-boot-1.1.5/board/atmel/at91sam9263ek/nand.c)
+ *     © Copyright 2006 ATMEL Rousset, Lacressonniere Nicolas
+ *
+ *  Add Programmable Multibit ECC support for various AT91 SoC
+ *     © Copyright 2012 ATMEL, Hong Xu
+ *
+ *  Add Nand Flash Controller support for SAMA5 SoC
+ *     © Copyright 2013 ATMEL, Josh Wu (josh.wu@atmel.com)
+ *
+ * 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/clk.h>
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/of_mtd.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/partitions.h>
+
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/platform_data/atmel.h>
+
+static int use_dma = 1;
+module_param(use_dma, int, 0);
+
+static int on_flash_bbt = 0;
+module_param(on_flash_bbt, int, 0);
+
+/* Register access macros */
+#define ecc_readl(add, reg)                            \
+       __raw_readl(add + ATMEL_ECC_##reg)
+#define ecc_writel(add, reg, value)                    \
+       __raw_writel((value), add + ATMEL_ECC_##reg)
+
+#include "atmel_nand_ecc.h"    /* Hardware ECC registers */
+#include "atmel_nand_nfc.h"    /* Nand Flash Controller definition */
+
+struct atmel_nand_caps {
+       bool pmecc_correct_erase_page;
+};
+
+/* oob layout for large page size
+ * bad block info is on bytes 0 and 1
+ * the bytes have to be consecutives to avoid
+ * several NAND_CMD_RNDOUT during read
+ */
+static struct nand_ecclayout atmel_oobinfo_large = {
+       .eccbytes = 4,
+       .eccpos = {60, 61, 62, 63},
+       .oobfree = {
+               {2, 58}
+       },
+};
+
+/* oob layout for small page size
+ * bad block info is on bytes 4 and 5
+ * the bytes have to be consecutives to avoid
+ * several NAND_CMD_RNDOUT during read
+ */
+static struct nand_ecclayout atmel_oobinfo_small = {
+       .eccbytes = 4,
+       .eccpos = {0, 1, 2, 3},
+       .oobfree = {
+               {6, 10}
+       },
+};
+
+struct atmel_nfc {
+       void __iomem            *base_cmd_regs;
+       void __iomem            *hsmc_regs;
+       void                    *sram_bank0;
+       dma_addr_t              sram_bank0_phys;
+       bool                    use_nfc_sram;
+       bool                    write_by_sram;
+
+       struct clk              *clk;
+
+       bool                    is_initialized;
+       struct completion       comp_ready;
+       struct completion       comp_cmd_done;
+       struct completion       comp_xfer_done;
+
+       /* Point to the sram bank which include readed data via NFC */
+       void                    *data_in_sram;
+       bool                    will_write_sram;
+};
+static struct atmel_nfc        nand_nfc;
+
+struct atmel_nand_host {
+       struct nand_chip        nand_chip;
+       struct mtd_info         mtd;
+       void __iomem            *io_base;
+       dma_addr_t              io_phys;
+       struct atmel_nand_data  board;
+       struct device           *dev;
+       void __iomem            *ecc;
+
+       struct completion       comp;
+       struct dma_chan         *dma_chan;
+
+       struct atmel_nfc        *nfc;
+
+       struct atmel_nand_caps  *caps;
+       bool                    has_pmecc;
+       u8                      pmecc_corr_cap;
+       u16                     pmecc_sector_size;
+       bool                    has_no_lookup_table;
+       u32                     pmecc_lookup_table_offset;
+       u32                     pmecc_lookup_table_offset_512;
+       u32                     pmecc_lookup_table_offset_1024;
+
+       int                     pmecc_degree;   /* Degree of remainders */
+       int                     pmecc_cw_len;   /* Length of codeword */
+
+       void __iomem            *pmerrloc_base;
+       void __iomem            *pmecc_rom_base;
+
+       /* lookup table for alpha_to and index_of */
+       void __iomem            *pmecc_alpha_to;
+       void __iomem            *pmecc_index_of;
+
+       /* data for pmecc computation */
+       int16_t                 *pmecc_partial_syn;
+       int16_t                 *pmecc_si;
+       int16_t                 *pmecc_smu;     /* Sigma table */
+       int16_t                 *pmecc_lmu;     /* polynomal order */
+       int                     *pmecc_mu;
+       int                     *pmecc_dmu;
+       int                     *pmecc_delta;
+};
+
+static struct nand_ecclayout atmel_pmecc_oobinfo;
+
+/*
+ * Enable NAND.
+ */
+static void atmel_nand_enable(struct atmel_nand_host *host)
+{
+       if (gpio_is_valid(host->board.enable_pin))
+               gpio_set_value(host->board.enable_pin, 0);
+}
+
+/*
+ * Disable NAND.
+ */
+static void atmel_nand_disable(struct atmel_nand_host *host)
+{
+       if (gpio_is_valid(host->board.enable_pin))
+               gpio_set_value(host->board.enable_pin, 1);
+}
+
+/*
+ * Hardware specific access to control-lines
+ */
+static void atmel_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
+{
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+
+       if (ctrl & NAND_CTRL_CHANGE) {
+               if (ctrl & NAND_NCE)
+                       atmel_nand_enable(host);
+               else
+                       atmel_nand_disable(host);
+       }
+       if (cmd == NAND_CMD_NONE)
+               return;
+
+       if (ctrl & NAND_CLE)
+               writeb(cmd, host->io_base + (1 << host->board.cle));
+       else
+               writeb(cmd, host->io_base + (1 << host->board.ale));
+}
+
+/*
+ * Read the Device Ready pin.
+ */
+static int atmel_nand_device_ready(struct mtd_info *mtd)
+{
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+
+       return gpio_get_value(host->board.rdy_pin) ^
+                !!host->board.rdy_pin_active_low;
+}
+
+/* Set up for hardware ready pin and enable pin. */
+static int atmel_nand_set_enable_ready_pins(struct mtd_info *mtd)
+{
+       struct nand_chip *chip = mtd->priv;
+       struct atmel_nand_host *host = chip->priv;
+       int res = 0;
+
+       if (gpio_is_valid(host->board.rdy_pin)) {
+               res = devm_gpio_request(host->dev,
+                               host->board.rdy_pin, "nand_rdy");
+               if (res < 0) {
+                       dev_err(host->dev,
+                               "can't request rdy gpio %d\n",
+                               host->board.rdy_pin);
+                       return res;
+               }
+
+               res = gpio_direction_input(host->board.rdy_pin);
+               if (res < 0) {
+                       dev_err(host->dev,
+                               "can't request input direction rdy gpio %d\n",
+                               host->board.rdy_pin);
+                       return res;
+               }
+
+               chip->dev_ready = atmel_nand_device_ready;
+       }
+
+       if (gpio_is_valid(host->board.enable_pin)) {
+               res = devm_gpio_request(host->dev,
+                               host->board.enable_pin, "nand_enable");
+               if (res < 0) {
+                       dev_err(host->dev,
+                               "can't request enable gpio %d\n",
+                               host->board.enable_pin);
+                       return res;
+               }
+
+               res = gpio_direction_output(host->board.enable_pin, 1);
+               if (res < 0) {
+                       dev_err(host->dev,
+                               "can't request output direction enable gpio %d\n",
+                               host->board.enable_pin);
+                       return res;
+               }
+       }
+
+       return res;
+}
+
+/*
+ * Minimal-overhead PIO for data access.
+ */
+static void atmel_read_buf8(struct mtd_info *mtd, u8 *buf, int len)
+{
+       struct nand_chip        *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+
+       if (host->nfc && host->nfc->use_nfc_sram && host->nfc->data_in_sram) {
+               memcpy(buf, host->nfc->data_in_sram, len);
+               host->nfc->data_in_sram += len;
+       } else {
+               __raw_readsb(nand_chip->IO_ADDR_R, buf, len);
+       }
+}
+
+static void atmel_read_buf16(struct mtd_info *mtd, u8 *buf, int len)
+{
+       struct nand_chip        *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+
+       if (host->nfc && host->nfc->use_nfc_sram && host->nfc->data_in_sram) {
+               memcpy(buf, host->nfc->data_in_sram, len);
+               host->nfc->data_in_sram += len;
+       } else {
+               __raw_readsw(nand_chip->IO_ADDR_R, buf, len / 2);
+       }
+}
+
+static void atmel_write_buf8(struct mtd_info *mtd, const u8 *buf, int len)
+{
+       struct nand_chip        *nand_chip = mtd->priv;
+
+       __raw_writesb(nand_chip->IO_ADDR_W, buf, len);
+}
+
+static void atmel_write_buf16(struct mtd_info *mtd, const u8 *buf, int len)
+{
+       struct nand_chip        *nand_chip = mtd->priv;
+
+       __raw_writesw(nand_chip->IO_ADDR_W, buf, len / 2);
+}
+
+static void dma_complete_func(void *completion)
+{
+       complete(completion);
+}
+
+static int nfc_set_sram_bank(struct atmel_nand_host *host, unsigned int bank)
+{
+       /* NFC only has two banks. Must be 0 or 1 */
+       if (bank > 1)
+               return -EINVAL;
+
+       if (bank) {
+               /* Only for a 2k-page or lower flash, NFC can handle 2 banks */
+               if (host->mtd.writesize > 2048)
+                       return -EINVAL;
+               nfc_writel(host->nfc->hsmc_regs, BANK, ATMEL_HSMC_NFC_BANK1);
+       } else {
+               nfc_writel(host->nfc->hsmc_regs, BANK, ATMEL_HSMC_NFC_BANK0);
+       }
+
+       return 0;
+}
+
+static uint nfc_get_sram_off(struct atmel_nand_host *host)
+{
+       if (nfc_readl(host->nfc->hsmc_regs, BANK) & ATMEL_HSMC_NFC_BANK1)
+               return NFC_SRAM_BANK1_OFFSET;
+       else
+               return 0;
+}
+
+static dma_addr_t nfc_sram_phys(struct atmel_nand_host *host)
+{
+       if (nfc_readl(host->nfc->hsmc_regs, BANK) & ATMEL_HSMC_NFC_BANK1)
+               return host->nfc->sram_bank0_phys + NFC_SRAM_BANK1_OFFSET;
+       else
+               return host->nfc->sram_bank0_phys;
+}
+
+static int atmel_nand_dma_op(struct mtd_info *mtd, void *buf, int len,
+                              int is_read)
+{
+       struct dma_device *dma_dev;
+       enum dma_ctrl_flags flags;
+       dma_addr_t dma_src_addr, dma_dst_addr, phys_addr;
+       struct dma_async_tx_descriptor *tx = NULL;
+       dma_cookie_t cookie;
+       struct nand_chip *chip = mtd->priv;
+       struct atmel_nand_host *host = chip->priv;
+       void *p = buf;
+       int err = -EIO;
+       enum dma_data_direction dir = is_read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+       struct atmel_nfc *nfc = host->nfc;
+
+       if (buf >= high_memory)
+               goto err_buf;
+
+       dma_dev = host->dma_chan->device;
+
+       flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
+
+       phys_addr = dma_map_single(dma_dev->dev, p, len, dir);
+       if (dma_mapping_error(dma_dev->dev, phys_addr)) {
+               dev_err(host->dev, "Failed to dma_map_single\n");
+               goto err_buf;
+       }
+
+       if (is_read) {
+               if (nfc && nfc->data_in_sram)
+                       dma_src_addr = nfc_sram_phys(host) + (nfc->data_in_sram
+                               - (nfc->sram_bank0 + nfc_get_sram_off(host)));
+               else
+                       dma_src_addr = host->io_phys;
+
+               dma_dst_addr = phys_addr;
+       } else {
+               dma_src_addr = phys_addr;
+
+               if (nfc && nfc->write_by_sram)
+                       dma_dst_addr = nfc_sram_phys(host);
+               else
+                       dma_dst_addr = host->io_phys;
+       }
+
+       tx = dma_dev->device_prep_dma_memcpy(host->dma_chan, dma_dst_addr,
+                                            dma_src_addr, len, flags);
+       if (!tx) {
+               dev_err(host->dev, "Failed to prepare DMA memcpy\n");
+               goto err_dma;
+       }
+
+       init_completion(&host->comp);
+       tx->callback = dma_complete_func;
+       tx->callback_param = &host->comp;
+
+       cookie = tx->tx_submit(tx);
+       if (dma_submit_error(cookie)) {
+               dev_err(host->dev, "Failed to do DMA tx_submit\n");
+               goto err_dma;
+       }
+
+       dma_async_issue_pending(host->dma_chan);
+       wait_for_completion(&host->comp);
+
+       if (is_read && nfc && nfc->data_in_sram)
+               /* After read data from SRAM, need to increase the position */
+               nfc->data_in_sram += len;
+
+       err = 0;
+
+err_dma:
+       dma_unmap_single(dma_dev->dev, phys_addr, len, dir);
+err_buf:
+       if (err != 0)
+               dev_dbg(host->dev, "Fall back to CPU I/O\n");
+       return err;
+}
+
+static void atmel_read_buf(struct mtd_info *mtd, u8 *buf, int len)
+{
+       struct nand_chip *chip = mtd->priv;
+       struct atmel_nand_host *host = chip->priv;
+
+       if (use_dma && len > mtd->oobsize)
+               /* only use DMA for bigger than oob size: better performances */
+               if (atmel_nand_dma_op(mtd, buf, len, 1) == 0)
+                       return;
+
+       if (host->board.bus_width_16)
+               atmel_read_buf16(mtd, buf, len);
+       else
+               atmel_read_buf8(mtd, buf, len);
+}
+
+static void atmel_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
+{
+       struct nand_chip *chip = mtd->priv;
+       struct atmel_nand_host *host = chip->priv;
+
+       if (use_dma && len > mtd->oobsize)
+               /* only use DMA for bigger than oob size: better performances */
+               if (atmel_nand_dma_op(mtd, (void *)buf, len, 0) == 0)
+                       return;
+
+       if (host->board.bus_width_16)
+               atmel_write_buf16(mtd, buf, len);
+       else
+               atmel_write_buf8(mtd, buf, len);
+}
+
+/*
+ * Return number of ecc bytes per sector according to sector size and
+ * correction capability
+ *
+ * Following table shows what at91 PMECC supported:
+ * Correction Capability       Sector_512_bytes        Sector_1024_bytes
+ * =====================       ================        =================
+ *                2-bits                 4-bytes                  4-bytes
+ *                4-bits                 7-bytes                  7-bytes
+ *                8-bits                13-bytes                 14-bytes
+ *               12-bits                20-bytes                 21-bytes
+ *               24-bits                39-bytes                 42-bytes
+ */
+static int pmecc_get_ecc_bytes(int cap, int sector_size)
+{
+       int m = 12 + sector_size / 512;
+       return (m * cap + 7) / 8;
+}
+
+static void pmecc_config_ecc_layout(struct nand_ecclayout *layout,
+                                   int oobsize, int ecc_len)
+{
+       int i;
+
+       layout->eccbytes = ecc_len;
+
+       /* ECC will occupy the last ecc_len bytes continuously */
+       for (i = 0; i < ecc_len; i++)
+               layout->eccpos[i] = oobsize - ecc_len + i;
+
+       layout->oobfree[0].offset = PMECC_OOB_RESERVED_BYTES;
+       layout->oobfree[0].length =
+               oobsize - ecc_len - layout->oobfree[0].offset;
+}
+
+static void __iomem *pmecc_get_alpha_to(struct atmel_nand_host *host)
+{
+       int table_size;
+
+       table_size = host->pmecc_sector_size == 512 ?
+               PMECC_LOOKUP_TABLE_SIZE_512 : PMECC_LOOKUP_TABLE_SIZE_1024;
+
+       return host->pmecc_rom_base + host->pmecc_lookup_table_offset +
+                       table_size * sizeof(int16_t);
+}
+
+static int pmecc_data_alloc(struct atmel_nand_host *host)
+{
+       const int cap = host->pmecc_corr_cap;
+       int size;
+
+       size = (2 * cap + 1) * sizeof(int16_t);
+       host->pmecc_partial_syn = devm_kzalloc(host->dev, size, GFP_KERNEL);
+       host->pmecc_si = devm_kzalloc(host->dev, size, GFP_KERNEL);
+       host->pmecc_lmu = devm_kzalloc(host->dev,
+                       (cap + 1) * sizeof(int16_t), GFP_KERNEL);
+       host->pmecc_smu = devm_kzalloc(host->dev,
+                       (cap + 2) * size, GFP_KERNEL);
+
+       size = (cap + 1) * sizeof(int);
+       host->pmecc_mu = devm_kzalloc(host->dev, size, GFP_KERNEL);
+       host->pmecc_dmu = devm_kzalloc(host->dev, size, GFP_KERNEL);
+       host->pmecc_delta = devm_kzalloc(host->dev, size, GFP_KERNEL);
+
+       if (!host->pmecc_partial_syn ||
+               !host->pmecc_si ||
+               !host->pmecc_lmu ||
+               !host->pmecc_smu ||
+               !host->pmecc_mu ||
+               !host->pmecc_dmu ||
+               !host->pmecc_delta)
+               return -ENOMEM;
+
+       return 0;
+}
+
+static void pmecc_gen_syndrome(struct mtd_info *mtd, int sector)
+{
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+       int i;
+       uint32_t value;
+
+       /* Fill odd syndromes */
+       for (i = 0; i < host->pmecc_corr_cap; i++) {
+               value = pmecc_readl_rem_relaxed(host->ecc, sector, i / 2);
+               if (i & 1)
+                       value >>= 16;
+               value &= 0xffff;
+               host->pmecc_partial_syn[(2 * i) + 1] = (int16_t)value;
+       }
+}
+
+static void pmecc_substitute(struct mtd_info *mtd)
+{
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+       int16_t __iomem *alpha_to = host->pmecc_alpha_to;
+       int16_t __iomem *index_of = host->pmecc_index_of;
+       int16_t *partial_syn = host->pmecc_partial_syn;
+       const int cap = host->pmecc_corr_cap;
+       int16_t *si;
+       int i, j;
+
+       /* si[] is a table that holds the current syndrome value,
+        * an element of that table belongs to the field
+        */
+       si = host->pmecc_si;
+
+       memset(&si[1], 0, sizeof(int16_t) * (2 * cap - 1));
+
+       /* Computation 2t syndromes based on S(x) */
+       /* Odd syndromes */
+       for (i = 1; i < 2 * cap; i += 2) {
+               for (j = 0; j < host->pmecc_degree; j++) {
+                       if (partial_syn[i] & ((unsigned short)0x1 << j))
+                               si[i] = readw_relaxed(alpha_to + i * j) ^ si[i];
+               }
+       }
+       /* Even syndrome = (Odd syndrome) ** 2 */
+       for (i = 2, j = 1; j <= cap; i = ++j << 1) {
+               if (si[j] == 0) {
+                       si[i] = 0;
+               } else {
+                       int16_t tmp;
+
+                       tmp = readw_relaxed(index_of + si[j]);
+                       tmp = (tmp * 2) % host->pmecc_cw_len;
+                       si[i] = readw_relaxed(alpha_to + tmp);
+               }
+       }
+
+       return;
+}
+
+static void pmecc_get_sigma(struct mtd_info *mtd)
+{
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+
+       int16_t *lmu = host->pmecc_lmu;
+       int16_t *si = host->pmecc_si;
+       int *mu = host->pmecc_mu;
+       int *dmu = host->pmecc_dmu;     /* Discrepancy */
+       int *delta = host->pmecc_delta; /* Delta order */
+       int cw_len = host->pmecc_cw_len;
+       const int16_t cap = host->pmecc_corr_cap;
+       const int num = 2 * cap + 1;
+       int16_t __iomem *index_of = host->pmecc_index_of;
+       int16_t __iomem *alpha_to = host->pmecc_alpha_to;
+       int i, j, k;
+       uint32_t dmu_0_count, tmp;
+       int16_t *smu = host->pmecc_smu;
+
+       /* index of largest delta */
+       int ro;
+       int largest;
+       int diff;
+
+       dmu_0_count = 0;
+
+       /* First Row */
+
+       /* Mu */
+       mu[0] = -1;
+
+       memset(smu, 0, sizeof(int16_t) * num);
+       smu[0] = 1;
+
+       /* discrepancy set to 1 */
+       dmu[0] = 1;
+       /* polynom order set to 0 */
+       lmu[0] = 0;
+       delta[0] = (mu[0] * 2 - lmu[0]) >> 1;
+
+       /* Second Row */
+
+       /* Mu */
+       mu[1] = 0;
+       /* Sigma(x) set to 1 */
+       memset(&smu[num], 0, sizeof(int16_t) * num);
+       smu[num] = 1;
+
+       /* discrepancy set to S1 */
+       dmu[1] = si[1];
+
+       /* polynom order set to 0 */
+       lmu[1] = 0;
+
+       delta[1] = (mu[1] * 2 - lmu[1]) >> 1;
+
+       /* Init the Sigma(x) last row */
+       memset(&smu[(cap + 1) * num], 0, sizeof(int16_t) * num);
+
+       for (i = 1; i <= cap; i++) {
+               mu[i + 1] = i << 1;
+               /* Begin Computing Sigma (Mu+1) and L(mu) */
+               /* check if discrepancy is set to 0 */
+               if (dmu[i] == 0) {
+                       dmu_0_count++;
+
+                       tmp = ((cap - (lmu[i] >> 1) - 1) / 2);
+                       if ((cap - (lmu[i] >> 1) - 1) & 0x1)
+                               tmp += 2;
+                       else
+                               tmp += 1;
+
+                       if (dmu_0_count == tmp) {
+                               for (j = 0; j <= (lmu[i] >> 1) + 1; j++)
+                                       smu[(cap + 1) * num + j] =
+                                                       smu[i * num + j];
+
+                               lmu[cap + 1] = lmu[i];
+                               return;
+                       }
+
+                       /* copy polynom */
+                       for (j = 0; j <= lmu[i] >> 1; j++)
+                               smu[(i + 1) * num + j] = smu[i * num + j];
+
+                       /* copy previous polynom order to the next */
+                       lmu[i + 1] = lmu[i];
+               } else {
+                       ro = 0;
+                       largest = -1;
+                       /* find largest delta with dmu != 0 */
+                       for (j = 0; j < i; j++) {
+                               if ((dmu[j]) && (delta[j] > largest)) {
+                                       largest = delta[j];
+                                       ro = j;
+                               }
+                       }
+
+                       /* compute difference */
+                       diff = (mu[i] - mu[ro]);
+
+                       /* Compute degree of the new smu polynomial */
+                       if ((lmu[i] >> 1) > ((lmu[ro] >> 1) + diff))
+                               lmu[i + 1] = lmu[i];
+                       else
+                               lmu[i + 1] = ((lmu[ro] >> 1) + diff) * 2;
+
+                       /* Init smu[i+1] with 0 */
+                       for (k = 0; k < num; k++)
+                               smu[(i + 1) * num + k] = 0;
+
+                       /* Compute smu[i+1] */
+                       for (k = 0; k <= lmu[ro] >> 1; k++) {
+                               int16_t a, b, c;
+
+                               if (!(smu[ro * num + k] && dmu[i]))
+                                       continue;
+                               a = readw_relaxed(index_of + dmu[i]);
+                               b = readw_relaxed(index_of + dmu[ro]);
+                               c = readw_relaxed(index_of + smu[ro * num + k]);
+                               tmp = a + (cw_len - b) + c;
+                               a = readw_relaxed(alpha_to + tmp % cw_len);
+                               smu[(i + 1) * num + (k + diff)] = a;
+                       }
+
+                       for (k = 0; k <= lmu[i] >> 1; k++)
+                               smu[(i + 1) * num + k] ^= smu[i * num + k];
+               }
+
+               /* End Computing Sigma (Mu+1) and L(mu) */
+               /* In either case compute delta */
+               delta[i + 1] = (mu[i + 1] * 2 - lmu[i + 1]) >> 1;
+
+               /* Do not compute discrepancy for the last iteration */
+               if (i >= cap)
+                       continue;
+
+               for (k = 0; k <= (lmu[i + 1] >> 1); k++) {
+                       tmp = 2 * (i - 1);
+                       if (k == 0) {
+                               dmu[i + 1] = si[tmp + 3];
+                       } else if (smu[(i + 1) * num + k] && si[tmp + 3 - k]) {
+                               int16_t a, b, c;
+                               a = readw_relaxed(index_of +
+                                               smu[(i + 1) * num + k]);
+                               b = si[2 * (i - 1) + 3 - k];
+                               c = readw_relaxed(index_of + b);
+                               tmp = a + c;
+                               tmp %= cw_len;
+                               dmu[i + 1] = readw_relaxed(alpha_to + tmp) ^
+                                       dmu[i + 1];
+                       }
+               }
+       }
+
+       return;
+}
+
+static int pmecc_err_location(struct mtd_info *mtd)
+{
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+       unsigned long end_time;
+       const int cap = host->pmecc_corr_cap;
+       const int num = 2 * cap + 1;
+       int sector_size = host->pmecc_sector_size;
+       int err_nbr = 0;        /* number of error */
+       int roots_nbr;          /* number of roots */
+       int i;
+       uint32_t val;
+       int16_t *smu = host->pmecc_smu;
+
+       pmerrloc_writel(host->pmerrloc_base, ELDIS, PMERRLOC_DISABLE);
+
+       for (i = 0; i <= host->pmecc_lmu[cap + 1] >> 1; i++) {
+               pmerrloc_writel_sigma_relaxed(host->pmerrloc_base, i,
+                                     smu[(cap + 1) * num + i]);
+               err_nbr++;
+       }
+
+       val = (err_nbr - 1) << 16;
+       if (sector_size == 1024)
+               val |= 1;
+
+       pmerrloc_writel(host->pmerrloc_base, ELCFG, val);
+       pmerrloc_writel(host->pmerrloc_base, ELEN,
+                       sector_size * 8 + host->pmecc_degree * cap);
+
+       end_time = jiffies + msecs_to_jiffies(PMECC_MAX_TIMEOUT_MS);
+       while (!(pmerrloc_readl_relaxed(host->pmerrloc_base, ELISR)
+                & PMERRLOC_CALC_DONE)) {
+               if (unlikely(time_after(jiffies, end_time))) {
+                       dev_err(host->dev, "PMECC: Timeout to calculate error location.\n");
+                       return -1;
+               }
+               cpu_relax();
+       }
+
+       roots_nbr = (pmerrloc_readl_relaxed(host->pmerrloc_base, ELISR)
+               & PMERRLOC_ERR_NUM_MASK) >> 8;
+       /* Number of roots == degree of smu hence <= cap */
+       if (roots_nbr == host->pmecc_lmu[cap + 1] >> 1)
+               return err_nbr - 1;
+
+       /* Number of roots does not match the degree of smu
+        * unable to correct error */
+       return -1;
+}
+
+static void pmecc_correct_data(struct mtd_info *mtd, uint8_t *buf, uint8_t *ecc,
+               int sector_num, int extra_bytes, int err_nbr)
+{
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+       int i = 0;
+       int byte_pos, bit_pos, sector_size, pos;
+       uint32_t tmp;
+       uint8_t err_byte;
+
+       sector_size = host->pmecc_sector_size;
+
+       while (err_nbr) {
+               tmp = pmerrloc_readl_el_relaxed(host->pmerrloc_base, i) - 1;
+               byte_pos = tmp / 8;
+               bit_pos  = tmp % 8;
+
+               if (byte_pos >= (sector_size + extra_bytes))
+                       BUG();  /* should never happen */
+
+               if (byte_pos < sector_size) {
+                       err_byte = *(buf + byte_pos);
+                       *(buf + byte_pos) ^= (1 << bit_pos);
+
+                       pos = sector_num * host->pmecc_sector_size + byte_pos;
+                       dev_info(host->dev, "Bit flip in data area, byte_pos: %d, bit_pos: %d, 0x%02x -> 0x%02x\n",
+                               pos, bit_pos, err_byte, *(buf + byte_pos));
+               } else {
+                       /* Bit flip in OOB area */
+                       tmp = sector_num * nand_chip->ecc.bytes
+                                       + (byte_pos - sector_size);
+                       err_byte = ecc[tmp];
+                       ecc[tmp] ^= (1 << bit_pos);
+
+                       pos = tmp + nand_chip->ecc.layout->eccpos[0];
+                       dev_info(host->dev, "Bit flip in OOB, oob_byte_pos: %d, bit_pos: %d, 0x%02x -> 0x%02x\n",
+                               pos, bit_pos, err_byte, ecc[tmp]);
+               }
+
+               i++;
+               err_nbr--;
+       }
+
+       return;
+}
+
+static int pmecc_correction(struct mtd_info *mtd, u32 pmecc_stat, uint8_t *buf,
+       u8 *ecc)
+{
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+       int i, err_nbr;
+       uint8_t *buf_pos;
+       int max_bitflips = 0;
+
+       /* If can correct bitfilps from erased page, do the normal check */
+       if (host->caps->pmecc_correct_erase_page)
+               goto normal_check;
+
+       for (i = 0; i < nand_chip->ecc.total; i++)
+               if (ecc[i] != 0xff)
+                       goto normal_check;
+       /* Erased page, return OK */
+       return 0;
+
+normal_check:
+       for (i = 0; i < nand_chip->ecc.steps; i++) {
+               err_nbr = 0;
+               if (pmecc_stat & 0x1) {
+                       buf_pos = buf + i * host->pmecc_sector_size;
+
+                       pmecc_gen_syndrome(mtd, i);
+                       pmecc_substitute(mtd);
+                       pmecc_get_sigma(mtd);
+
+                       err_nbr = pmecc_err_location(mtd);
+                       if (err_nbr == -1) {
+                               dev_err(host->dev, "PMECC: Too many errors\n");
+                               mtd->ecc_stats.failed++;
+                               return -EIO;
+                       } else {
+                               pmecc_correct_data(mtd, buf_pos, ecc, i,
+                                       nand_chip->ecc.bytes, err_nbr);
+                               mtd->ecc_stats.corrected += err_nbr;
+                               max_bitflips = max_t(int, max_bitflips, err_nbr);
+                       }
+               }
+               pmecc_stat >>= 1;
+       }
+
+       return max_bitflips;
+}
+
+static void pmecc_enable(struct atmel_nand_host *host, int ecc_op)
+{
+       u32 val;
+
+       if (ecc_op != NAND_ECC_READ && ecc_op != NAND_ECC_WRITE) {
+               dev_err(host->dev, "atmel_nand: wrong pmecc operation type!");
+               return;
+       }
+
+       pmecc_writel(host->ecc, CTRL, PMECC_CTRL_RST);
+       pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DISABLE);
+       val = pmecc_readl_relaxed(host->ecc, CFG);
+
+       if (ecc_op == NAND_ECC_READ)
+               pmecc_writel(host->ecc, CFG, (val & ~PMECC_CFG_WRITE_OP)
+                       | PMECC_CFG_AUTO_ENABLE);
+       else
+               pmecc_writel(host->ecc, CFG, (val | PMECC_CFG_WRITE_OP)
+                       & ~PMECC_CFG_AUTO_ENABLE);
+
+       pmecc_writel(host->ecc, CTRL, PMECC_CTRL_ENABLE);
+       pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DATA);
+}
+
+static int atmel_nand_pmecc_read_page(struct mtd_info *mtd,
+       struct nand_chip *chip, uint8_t *buf, int oob_required, int page)
+{
+       struct atmel_nand_host *host = chip->priv;
+       int eccsize = chip->ecc.size * chip->ecc.steps;
+       uint8_t *oob = chip->oob_poi;
+       uint32_t *eccpos = chip->ecc.layout->eccpos;
+       uint32_t stat;
+       unsigned long end_time;
+       int bitflips = 0;
+
+       if (!host->nfc || !host->nfc->use_nfc_sram)
+               pmecc_enable(host, NAND_ECC_READ);
+
+       chip->read_buf(mtd, buf, eccsize);
+       chip->read_buf(mtd, oob, mtd->oobsize);
+
+       end_time = jiffies + msecs_to_jiffies(PMECC_MAX_TIMEOUT_MS);
+       while ((pmecc_readl_relaxed(host->ecc, SR) & PMECC_SR_BUSY)) {
+               if (unlikely(time_after(jiffies, end_time))) {
+                       dev_err(host->dev, "PMECC: Timeout to get error status.\n");
+                       return -EIO;
+               }
+               cpu_relax();
+       }
+
+       stat = pmecc_readl_relaxed(host->ecc, ISR);
+       if (stat != 0) {
+               bitflips = pmecc_correction(mtd, stat, buf, &oob[eccpos[0]]);
+               if (bitflips < 0)
+                       /* uncorrectable errors */
+                       return 0;
+       }
+
+       return bitflips;
+}
+
+static int atmel_nand_pmecc_write_page(struct mtd_info *mtd,
+               struct nand_chip *chip, const uint8_t *buf, int oob_required)
+{
+       struct atmel_nand_host *host = chip->priv;
+       uint32_t *eccpos = chip->ecc.layout->eccpos;
+       int i, j;
+       unsigned long end_time;
+
+       if (!host->nfc || !host->nfc->write_by_sram) {
+               pmecc_enable(host, NAND_ECC_WRITE);
+               chip->write_buf(mtd, (u8 *)buf, mtd->writesize);
+       }
+
+       end_time = jiffies + msecs_to_jiffies(PMECC_MAX_TIMEOUT_MS);
+       while ((pmecc_readl_relaxed(host->ecc, SR) & PMECC_SR_BUSY)) {
+               if (unlikely(time_after(jiffies, end_time))) {
+                       dev_err(host->dev, "PMECC: Timeout to get ECC value.\n");
+                       return -EIO;
+               }
+               cpu_relax();
+       }
+
+       for (i = 0; i < chip->ecc.steps; i++) {
+               for (j = 0; j < chip->ecc.bytes; j++) {
+                       int pos;
+
+                       pos = i * chip->ecc.bytes + j;
+                       chip->oob_poi[eccpos[pos]] =
+                               pmecc_readb_ecc_relaxed(host->ecc, i, j);
+               }
+       }
+       chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
+
+       return 0;
+}
+
+static void atmel_pmecc_core_init(struct mtd_info *mtd)
+{
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+       uint32_t val = 0;
+       struct nand_ecclayout *ecc_layout;
+
+       pmecc_writel(host->ecc, CTRL, PMECC_CTRL_RST);
+       pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DISABLE);
+
+       switch (host->pmecc_corr_cap) {
+       case 2:
+               val = PMECC_CFG_BCH_ERR2;
+               break;
+       case 4:
+               val = PMECC_CFG_BCH_ERR4;
+               break;
+       case 8:
+               val = PMECC_CFG_BCH_ERR8;
+               break;
+       case 12:
+               val = PMECC_CFG_BCH_ERR12;
+               break;
+       case 24:
+               val = PMECC_CFG_BCH_ERR24;
+               break;
+       }
+
+       if (host->pmecc_sector_size == 512)
+               val |= PMECC_CFG_SECTOR512;
+       else if (host->pmecc_sector_size == 1024)
+               val |= PMECC_CFG_SECTOR1024;
+
+       switch (nand_chip->ecc.steps) {
+       case 1:
+               val |= PMECC_CFG_PAGE_1SECTOR;
+               break;
+       case 2:
+               val |= PMECC_CFG_PAGE_2SECTORS;
+               break;
+       case 4:
+               val |= PMECC_CFG_PAGE_4SECTORS;
+               break;
+       case 8:
+               val |= PMECC_CFG_PAGE_8SECTORS;
+               break;
+       }
+
+       val |= (PMECC_CFG_READ_OP | PMECC_CFG_SPARE_DISABLE
+               | PMECC_CFG_AUTO_DISABLE);
+       pmecc_writel(host->ecc, CFG, val);
+
+       ecc_layout = nand_chip->ecc.layout;
+       pmecc_writel(host->ecc, SAREA, mtd->oobsize - 1);
+       pmecc_writel(host->ecc, SADDR, ecc_layout->eccpos[0]);
+       pmecc_writel(host->ecc, EADDR,
+                       ecc_layout->eccpos[ecc_layout->eccbytes - 1]);
+       /* See datasheet about PMECC Clock Control Register */
+       pmecc_writel(host->ecc, CLK, 2);
+       pmecc_writel(host->ecc, IDR, 0xff);
+       pmecc_writel(host->ecc, CTRL, PMECC_CTRL_ENABLE);
+}
+
+/*
+ * Get minimum ecc requirements from NAND.
+ * If pmecc-cap, pmecc-sector-size in DTS are not specified, this function
+ * will set them according to minimum ecc requirement. Otherwise, use the
+ * value in DTS file.
+ * return 0 if success. otherwise return error code.
+ */
+static int pmecc_choose_ecc(struct atmel_nand_host *host,
+               int *cap, int *sector_size)
+{
+       /* Get minimum ECC requirements */
+       if (host->nand_chip.ecc_strength_ds) {
+               *cap = host->nand_chip.ecc_strength_ds;
+               *sector_size = host->nand_chip.ecc_step_ds;
+               dev_info(host->dev, "minimum ECC: %d bits in %d bytes\n",
+                               *cap, *sector_size);
+       } else {
+               *cap = 2;
+               *sector_size = 512;
+               dev_info(host->dev, "can't detect min. ECC, assume 2 bits in 512 bytes\n");
+       }
+
+       /* If device tree doesn't specify, use NAND's minimum ECC parameters */
+       if (host->pmecc_corr_cap == 0) {
+               /* use the most fitable ecc bits (the near bigger one ) */
+               if (*cap <= 2)
+                       host->pmecc_corr_cap = 2;
+               else if (*cap <= 4)
+                       host->pmecc_corr_cap = 4;
+               else if (*cap <= 8)
+                       host->pmecc_corr_cap = 8;
+               else if (*cap <= 12)
+                       host->pmecc_corr_cap = 12;
+               else if (*cap <= 24)
+                       host->pmecc_corr_cap = 24;
+               else
+                       return -EINVAL;
+       }
+       if (host->pmecc_sector_size == 0) {
+               /* use the most fitable sector size (the near smaller one ) */
+               if (*sector_size >= 1024)
+                       host->pmecc_sector_size = 1024;
+               else if (*sector_size >= 512)
+                       host->pmecc_sector_size = 512;
+               else
+                       return -EINVAL;
+       }
+       return 0;
+}
+
+static inline int deg(unsigned int poly)
+{
+       /* polynomial degree is the most-significant bit index */
+       return fls(poly) - 1;
+}
+
+static int build_gf_tables(int mm, unsigned int poly,
+               int16_t *index_of, int16_t *alpha_to)
+{
+       unsigned int i, x = 1;
+       const unsigned int k = 1 << deg(poly);
+       unsigned int nn = (1 << mm) - 1;
+
+       /* primitive polynomial must be of degree m */
+       if (k != (1u << mm))
+               return -EINVAL;
+
+       for (i = 0; i < nn; i++) {
+               alpha_to[i] = x;
+               index_of[x] = i;
+               if (i && (x == 1))
+                       /* polynomial is not primitive (a^i=1 with 0<i<2^m-1) */
+                       return -EINVAL;
+               x <<= 1;
+               if (x & k)
+                       x ^= poly;
+       }
+       alpha_to[nn] = 1;
+       index_of[0] = 0;
+
+       return 0;
+}
+
+static uint16_t *create_lookup_table(struct device *dev, int sector_size)
+{
+       int degree = (sector_size == 512) ?
+                       PMECC_GF_DIMENSION_13 :
+                       PMECC_GF_DIMENSION_14;
+       unsigned int poly = (sector_size == 512) ?
+                       PMECC_GF_13_PRIMITIVE_POLY :
+                       PMECC_GF_14_PRIMITIVE_POLY;
+       int table_size = (sector_size == 512) ?
+                       PMECC_LOOKUP_TABLE_SIZE_512 :
+                       PMECC_LOOKUP_TABLE_SIZE_1024;
+
+       int16_t *addr = devm_kzalloc(dev, 2 * table_size * sizeof(uint16_t),
+                       GFP_KERNEL);
+       if (addr && build_gf_tables(degree, poly, addr, addr + table_size))
+               return NULL;
+
+       return addr;
+}
+
+static int atmel_pmecc_nand_init_params(struct platform_device *pdev,
+                                        struct atmel_nand_host *host)
+{
+       struct mtd_info *mtd = &host->mtd;
+       struct nand_chip *nand_chip = &host->nand_chip;
+       struct resource *regs, *regs_pmerr, *regs_rom;
+       uint16_t *galois_table;
+       int cap, sector_size, err_no;
+
+       err_no = pmecc_choose_ecc(host, &cap, &sector_size);
+       if (err_no) {
+               dev_err(host->dev, "The NAND flash's ECC requirement are not support!");
+               return err_no;
+       }
+
+       if (cap > host->pmecc_corr_cap ||
+                       sector_size != host->pmecc_sector_size)
+               dev_info(host->dev, "WARNING: Be Caution! Using different PMECC parameters from Nand ONFI ECC reqirement.\n");
+
+       cap = host->pmecc_corr_cap;
+       sector_size = host->pmecc_sector_size;
+       host->pmecc_lookup_table_offset = (sector_size == 512) ?
+                       host->pmecc_lookup_table_offset_512 :
+                       host->pmecc_lookup_table_offset_1024;
+
+       dev_info(host->dev, "Initialize PMECC params, cap: %d, sector: %d\n",
+                cap, sector_size);
+
+       regs = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+       if (!regs) {
+               dev_warn(host->dev,
+                       "Can't get I/O resource regs for PMECC controller, rolling back on software ECC\n");
+               nand_chip->ecc.mode = NAND_ECC_SOFT;
+               return 0;
+       }
+
+       host->ecc = devm_ioremap_resource(&pdev->dev, regs);
+       if (IS_ERR(host->ecc)) {
+               err_no = PTR_ERR(host->ecc);
+               goto err;
+       }
+
+       regs_pmerr = platform_get_resource(pdev, IORESOURCE_MEM, 2);
+       host->pmerrloc_base = devm_ioremap_resource(&pdev->dev, regs_pmerr);
+       if (IS_ERR(host->pmerrloc_base)) {
+               err_no = PTR_ERR(host->pmerrloc_base);
+               goto err;
+       }
+
+       if (!host->has_no_lookup_table) {
+               regs_rom = platform_get_resource(pdev, IORESOURCE_MEM, 3);
+               host->pmecc_rom_base = devm_ioremap_resource(&pdev->dev,
+                                                               regs_rom);
+               if (IS_ERR(host->pmecc_rom_base)) {
+                       dev_err(host->dev, "Can not get I/O resource for ROM, will build a lookup table in runtime!\n");
+                       host->has_no_lookup_table = true;
+               }
+       }
+
+       if (host->has_no_lookup_table) {
+               /* Build the look-up table in runtime */
+               galois_table = create_lookup_table(host->dev, sector_size);
+               if (!galois_table) {
+                       dev_err(host->dev, "Failed to build a lookup table in runtime!\n");
+                       err_no = -EINVAL;
+                       goto err;
+               }
+
+               host->pmecc_rom_base = (void __iomem *)galois_table;
+               host->pmecc_lookup_table_offset = 0;
+       }
+
+       nand_chip->ecc.size = sector_size;
+
+       /* set ECC page size and oob layout */
+       switch (mtd->writesize) {
+       case 512:
+       case 1024:
+       case 2048:
+       case 4096:
+       case 8192:
+               if (sector_size > mtd->writesize) {
+                       dev_err(host->dev, "pmecc sector size is bigger than the page size!\n");
+                       err_no = -EINVAL;
+                       goto err;
+               }
+
+               host->pmecc_degree = (sector_size == 512) ?
+                       PMECC_GF_DIMENSION_13 : PMECC_GF_DIMENSION_14;
+               host->pmecc_cw_len = (1 << host->pmecc_degree) - 1;
+               host->pmecc_alpha_to = pmecc_get_alpha_to(host);
+               host->pmecc_index_of = host->pmecc_rom_base +
+                       host->pmecc_lookup_table_offset;
+
+               nand_chip->ecc.strength = cap;
+               nand_chip->ecc.bytes = pmecc_get_ecc_bytes(cap, sector_size);
+               nand_chip->ecc.steps = mtd->writesize / sector_size;
+               nand_chip->ecc.total = nand_chip->ecc.bytes *
+                       nand_chip->ecc.steps;
+               if (nand_chip->ecc.total >
+                               mtd->oobsize - PMECC_OOB_RESERVED_BYTES) {
+                       dev_err(host->dev, "No room for ECC bytes\n");
+                       err_no = -EINVAL;
+                       goto err;
+               }
+               pmecc_config_ecc_layout(&atmel_pmecc_oobinfo,
+                                       mtd->oobsize,
+                                       nand_chip->ecc.total);
+
+               nand_chip->ecc.layout = &atmel_pmecc_oobinfo;
+               break;
+       default:
+               dev_warn(host->dev,
+                       "Unsupported page size for PMECC, use Software ECC\n");
+               /* page size not handled by HW ECC */
+               /* switching back to soft ECC */
+               nand_chip->ecc.mode = NAND_ECC_SOFT;
+               return 0;
+       }
+
+       /* Allocate data for PMECC computation */
+       err_no = pmecc_data_alloc(host);
+       if (err_no) {
+               dev_err(host->dev,
+                               "Cannot allocate memory for PMECC computation!\n");
+               goto err;
+       }
+
+       nand_chip->options |= NAND_NO_SUBPAGE_WRITE;
+       nand_chip->ecc.read_page = atmel_nand_pmecc_read_page;
+       nand_chip->ecc.write_page = atmel_nand_pmecc_write_page;
+
+       atmel_pmecc_core_init(mtd);
+
+       return 0;
+
+err:
+       return err_no;
+}
+
+/*
+ * Calculate HW ECC
+ *
+ * function called after a write
+ *
+ * mtd:        MTD block structure
+ * dat:        raw data (unused)
+ * ecc_code:   buffer for ECC
+ */
+static int atmel_nand_calculate(struct mtd_info *mtd,
+               const u_char *dat, unsigned char *ecc_code)
+{
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+       unsigned int ecc_value;
+
+       /* get the first 2 ECC bytes */
+       ecc_value = ecc_readl(host->ecc, PR);
+
+       ecc_code[0] = ecc_value & 0xFF;
+       ecc_code[1] = (ecc_value >> 8) & 0xFF;
+
+       /* get the last 2 ECC bytes */
+       ecc_value = ecc_readl(host->ecc, NPR) & ATMEL_ECC_NPARITY;
+
+       ecc_code[2] = ecc_value & 0xFF;
+       ecc_code[3] = (ecc_value >> 8) & 0xFF;
+
+       return 0;
+}
+
+/*
+ * HW ECC read page function
+ *
+ * mtd:        mtd info structure
+ * chip:       nand chip info structure
+ * buf:        buffer to store read data
+ * oob_required:    caller expects OOB data read to chip->oob_poi
+ */
+static int atmel_nand_read_page(struct mtd_info *mtd, struct nand_chip *chip,
+                               uint8_t *buf, int oob_required, int page)
+{
+       int eccsize = chip->ecc.size;
+       int eccbytes = chip->ecc.bytes;
+       uint32_t *eccpos = chip->ecc.layout->eccpos;
+       uint8_t *p = buf;
+       uint8_t *oob = chip->oob_poi;
+       uint8_t *ecc_pos;
+       int stat;
+       unsigned int max_bitflips = 0;
+
+       /*
+        * Errata: ALE is incorrectly wired up to the ECC controller
+        * on the AP7000, so it will include the address cycles in the
+        * ECC calculation.
+        *
+        * Workaround: Reset the parity registers before reading the
+        * actual data.
+        */
+       struct atmel_nand_host *host = chip->priv;
+       if (host->board.need_reset_workaround)
+               ecc_writel(host->ecc, CR, ATMEL_ECC_RST);
+
+       /* read the page */
+       chip->read_buf(mtd, p, eccsize);
+
+       /* move to ECC position if needed */
+       if (eccpos[0] != 0) {
+               /* This only works on large pages
+                * because the ECC controller waits for
+                * NAND_CMD_RNDOUTSTART after the
+                * NAND_CMD_RNDOUT.
+                * anyway, for small pages, the eccpos[0] == 0
+                */
+               chip->cmdfunc(mtd, NAND_CMD_RNDOUT,
+                               mtd->writesize + eccpos[0], -1);
+       }
+
+       /* the ECC controller needs to read the ECC just after the data */
+       ecc_pos = oob + eccpos[0];
+       chip->read_buf(mtd, ecc_pos, eccbytes);
+
+       /* check if there's an error */
+       stat = chip->ecc.correct(mtd, p, oob, NULL);
+
+       if (stat < 0) {
+               mtd->ecc_stats.failed++;
+       } else {
+               mtd->ecc_stats.corrected += stat;
+               max_bitflips = max_t(unsigned int, max_bitflips, stat);
+       }
+
+       /* get back to oob start (end of page) */
+       chip->cmdfunc(mtd, NAND_CMD_RNDOUT, mtd->writesize, -1);
+
+       /* read the oob */
+       chip->read_buf(mtd, oob, mtd->oobsize);
+
+       return max_bitflips;
+}
+
+/*
+ * HW ECC Correction
+ *
+ * function called after a read
+ *
+ * mtd:        MTD block structure
+ * dat:        raw data read from the chip
+ * read_ecc:   ECC from the chip (unused)
+ * isnull:     unused
+ *
+ * Detect and correct a 1 bit error for a page
+ */
+static int atmel_nand_correct(struct mtd_info *mtd, u_char *dat,
+               u_char *read_ecc, u_char *isnull)
+{
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+       unsigned int ecc_status;
+       unsigned int ecc_word, ecc_bit;
+
+       /* get the status from the Status Register */
+       ecc_status = ecc_readl(host->ecc, SR);
+
+       /* if there's no error */
+       if (likely(!(ecc_status & ATMEL_ECC_RECERR)))
+               return 0;
+
+       /* get error bit offset (4 bits) */
+       ecc_bit = ecc_readl(host->ecc, PR) & ATMEL_ECC_BITADDR;
+       /* get word address (12 bits) */
+       ecc_word = ecc_readl(host->ecc, PR) & ATMEL_ECC_WORDADDR;
+       ecc_word >>= 4;
+
+       /* if there are multiple errors */
+       if (ecc_status & ATMEL_ECC_MULERR) {
+               /* check if it is a freshly erased block
+                * (filled with 0xff) */
+               if ((ecc_bit == ATMEL_ECC_BITADDR)
+                               && (ecc_word == (ATMEL_ECC_WORDADDR >> 4))) {
+                       /* the block has just been erased, return OK */
+                       return 0;
+               }
+               /* it doesn't seems to be a freshly
+                * erased block.
+                * We can't correct so many errors */
+               dev_dbg(host->dev, "atmel_nand : multiple errors detected."
+                               " Unable to correct.\n");
+               return -EIO;
+       }
+
+       /* if there's a single bit error : we can correct it */
+       if (ecc_status & ATMEL_ECC_ECCERR) {
+               /* there's nothing much to do here.
+                * the bit error is on the ECC itself.
+                */
+               dev_dbg(host->dev, "atmel_nand : one bit error on ECC code."
+                               " Nothing to correct\n");
+               return 0;
+       }
+
+       dev_dbg(host->dev, "atmel_nand : one bit error on data."
+                       " (word offset in the page :"
+                       " 0x%x bit offset : 0x%x)\n",
+                       ecc_word, ecc_bit);
+       /* correct the error */
+       if (nand_chip->options & NAND_BUSWIDTH_16) {
+               /* 16 bits words */
+               ((unsigned short *) dat)[ecc_word] ^= (1 << ecc_bit);
+       } else {
+               /* 8 bits words */
+               dat[ecc_word] ^= (1 << ecc_bit);
+       }
+       dev_dbg(host->dev, "atmel_nand : error corrected\n");
+       return 1;
+}
+
+/*
+ * Enable HW ECC : unused on most chips
+ */
+static void atmel_nand_hwctl(struct mtd_info *mtd, int mode)
+{
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+
+       if (host->board.need_reset_workaround)
+               ecc_writel(host->ecc, CR, ATMEL_ECC_RST);
+}
+
+static const struct of_device_id atmel_nand_dt_ids[];
+
+static int atmel_of_init_port(struct atmel_nand_host *host,
+                             struct device_node *np)
+{
+       u32 val;
+       u32 offset[2];
+       int ecc_mode;
+       struct atmel_nand_data *board = &host->board;
+       enum of_gpio_flags flags = 0;
+
+       host->caps = (struct atmel_nand_caps *)
+               of_match_device(atmel_nand_dt_ids, host->dev)->data;
+
+       if (of_property_read_u32(np, "atmel,nand-addr-offset", &val) == 0) {
+               if (val >= 32) {
+                       dev_err(host->dev, "invalid addr-offset %u\n", val);
+                       return -EINVAL;
+               }
+               board->ale = val;
+       }
+
+       if (of_property_read_u32(np, "atmel,nand-cmd-offset", &val) == 0) {
+               if (val >= 32) {
+                       dev_err(host->dev, "invalid cmd-offset %u\n", val);
+                       return -EINVAL;
+               }
+               board->cle = val;
+       }
+
+       ecc_mode = of_get_nand_ecc_mode(np);
+
+       board->ecc_mode = ecc_mode < 0 ? NAND_ECC_SOFT : ecc_mode;
+
+       board->on_flash_bbt = of_get_nand_on_flash_bbt(np);
+
+       board->has_dma = of_property_read_bool(np, "atmel,nand-has-dma");
+
+       if (of_get_nand_bus_width(np) == 16)
+               board->bus_width_16 = 1;
+
+       board->rdy_pin = of_get_gpio_flags(np, 0, &flags);
+       board->rdy_pin_active_low = (flags == OF_GPIO_ACTIVE_LOW);
+
+       board->enable_pin = of_get_gpio(np, 1);
+       board->det_pin = of_get_gpio(np, 2);
+
+       host->has_pmecc = of_property_read_bool(np, "atmel,has-pmecc");
+
+       /* load the nfc driver if there is */
+       of_platform_populate(np, NULL, NULL, host->dev);
+
+       if (!(board->ecc_mode == NAND_ECC_HW) || !host->has_pmecc)
+               return 0;       /* Not using PMECC */
+
+       /* use PMECC, get correction capability, sector size and lookup
+        * table offset.
+        * If correction bits and sector size are not specified, then find
+        * them from NAND ONFI parameters.
+        */
+       if (of_property_read_u32(np, "atmel,pmecc-cap", &val) == 0) {
+               if ((val != 2) && (val != 4) && (val != 8) && (val != 12) &&
+                               (val != 24)) {
+                       dev_err(host->dev,
+                               "Unsupported PMECC correction capability: %d; should be 2, 4, 8, 12 or 24\n",
+                               val);
+                       return -EINVAL;
+               }
+               host->pmecc_corr_cap = (u8)val;
+       }
+
+       if (of_property_read_u32(np, "atmel,pmecc-sector-size", &val) == 0) {
+               if ((val != 512) && (val != 1024)) {
+                       dev_err(host->dev,
+                               "Unsupported PMECC sector size: %d; should be 512 or 1024 bytes\n",
+                               val);
+                       return -EINVAL;
+               }
+               host->pmecc_sector_size = (u16)val;
+       }
+
+       if (of_property_read_u32_array(np, "atmel,pmecc-lookup-table-offset",
+                       offset, 2) != 0) {
+               dev_err(host->dev, "Cannot get PMECC lookup table offset, will build a lookup table in runtime.\n");
+               host->has_no_lookup_table = true;
+               /* Will build a lookup table and initialize the offset later */
+               return 0;
+       }
+       if (!offset[0] && !offset[1]) {
+               dev_err(host->dev, "Invalid PMECC lookup table offset\n");
+               return -EINVAL;
+       }
+       host->pmecc_lookup_table_offset_512 = offset[0];
+       host->pmecc_lookup_table_offset_1024 = offset[1];
+
+       return 0;
+}
+
+static int atmel_hw_nand_init_params(struct platform_device *pdev,
+                                        struct atmel_nand_host *host)
+{
+       struct mtd_info *mtd = &host->mtd;
+       struct nand_chip *nand_chip = &host->nand_chip;
+       struct resource         *regs;
+
+       regs = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+       if (!regs) {
+               dev_err(host->dev,
+                       "Can't get I/O resource regs, use software ECC\n");
+               nand_chip->ecc.mode = NAND_ECC_SOFT;
+               return 0;
+       }
+
+       host->ecc = devm_ioremap_resource(&pdev->dev, regs);
+       if (IS_ERR(host->ecc))
+               return PTR_ERR(host->ecc);
+
+       /* ECC is calculated for the whole page (1 step) */
+       nand_chip->ecc.size = mtd->writesize;
+
+       /* set ECC page size and oob layout */
+       switch (mtd->writesize) {
+       case 512:
+               nand_chip->ecc.layout = &atmel_oobinfo_small;
+               ecc_writel(host->ecc, MR, ATMEL_ECC_PAGESIZE_528);
+               break;
+       case 1024:
+               nand_chip->ecc.layout = &atmel_oobinfo_large;
+               ecc_writel(host->ecc, MR, ATMEL_ECC_PAGESIZE_1056);
+               break;
+       case 2048:
+               nand_chip->ecc.layout = &atmel_oobinfo_large;
+               ecc_writel(host->ecc, MR, ATMEL_ECC_PAGESIZE_2112);
+               break;
+       case 4096:
+               nand_chip->ecc.layout = &atmel_oobinfo_large;
+               ecc_writel(host->ecc, MR, ATMEL_ECC_PAGESIZE_4224);
+               break;
+       default:
+               /* page size not handled by HW ECC */
+               /* switching back to soft ECC */
+               nand_chip->ecc.mode = NAND_ECC_SOFT;
+               return 0;
+       }
+
+       /* set up for HW ECC */
+       nand_chip->ecc.calculate = atmel_nand_calculate;
+       nand_chip->ecc.correct = atmel_nand_correct;
+       nand_chip->ecc.hwctl = atmel_nand_hwctl;
+       nand_chip->ecc.read_page = atmel_nand_read_page;
+       nand_chip->ecc.bytes = 4;
+       nand_chip->ecc.strength = 1;
+
+       return 0;
+}
+
+static inline u32 nfc_read_status(struct atmel_nand_host *host)
+{
+       u32 err_flags = NFC_SR_DTOE | NFC_SR_UNDEF | NFC_SR_AWB | NFC_SR_ASE;
+       u32 nfc_status = nfc_readl(host->nfc->hsmc_regs, SR);
+
+       if (unlikely(nfc_status & err_flags)) {
+               if (nfc_status & NFC_SR_DTOE)
+                       dev_err(host->dev, "NFC: Waiting Nand R/B Timeout Error\n");
+               else if (nfc_status & NFC_SR_UNDEF)
+                       dev_err(host->dev, "NFC: Access Undefined Area Error\n");
+               else if (nfc_status & NFC_SR_AWB)
+                       dev_err(host->dev, "NFC: Access memory While NFC is busy\n");
+               else if (nfc_status & NFC_SR_ASE)
+                       dev_err(host->dev, "NFC: Access memory Size Error\n");
+       }
+
+       return nfc_status;
+}
+
+/* SMC interrupt service routine */
+static irqreturn_t hsmc_interrupt(int irq, void *dev_id)
+{
+       struct atmel_nand_host *host = dev_id;
+       u32 status, mask, pending;
+       irqreturn_t ret = IRQ_NONE;
+
+       status = nfc_read_status(host);
+       mask = nfc_readl(host->nfc->hsmc_regs, IMR);
+       pending = status & mask;
+
+       if (pending & NFC_SR_XFR_DONE) {
+               complete(&host->nfc->comp_xfer_done);
+               nfc_writel(host->nfc->hsmc_regs, IDR, NFC_SR_XFR_DONE);
+               ret = IRQ_HANDLED;
+       }
+       if (pending & NFC_SR_RB_EDGE) {
+               complete(&host->nfc->comp_ready);
+               nfc_writel(host->nfc->hsmc_regs, IDR, NFC_SR_RB_EDGE);
+               ret = IRQ_HANDLED;
+       }
+       if (pending & NFC_SR_CMD_DONE) {
+               complete(&host->nfc->comp_cmd_done);
+               nfc_writel(host->nfc->hsmc_regs, IDR, NFC_SR_CMD_DONE);
+               ret = IRQ_HANDLED;
+       }
+
+       return ret;
+}
+
+/* NFC(Nand Flash Controller) related functions */
+static void nfc_prepare_interrupt(struct atmel_nand_host *host, u32 flag)
+{
+       if (flag & NFC_SR_XFR_DONE)
+               init_completion(&host->nfc->comp_xfer_done);
+
+       if (flag & NFC_SR_RB_EDGE)
+               init_completion(&host->nfc->comp_ready);
+
+       if (flag & NFC_SR_CMD_DONE)
+               init_completion(&host->nfc->comp_cmd_done);
+
+       /* Enable interrupt that need to wait for */
+       nfc_writel(host->nfc->hsmc_regs, IER, flag);
+}
+
+static int nfc_wait_interrupt(struct atmel_nand_host *host, u32 flag)
+{
+       int i, index = 0;
+       struct completion *comp[3];     /* Support 3 interrupt completion */
+
+       if (flag & NFC_SR_XFR_DONE)
+               comp[index++] = &host->nfc->comp_xfer_done;
+
+       if (flag & NFC_SR_RB_EDGE)
+               comp[index++] = &host->nfc->comp_ready;
+
+       if (flag & NFC_SR_CMD_DONE)
+               comp[index++] = &host->nfc->comp_cmd_done;
+
+       if (index == 0) {
+               dev_err(host->dev, "Unknown interrupt flag: 0x%08x\n", flag);
+               return -EINVAL;
+       }
+
+       for (i = 0; i < index; i++) {
+               if (wait_for_completion_timeout(comp[i],
+                               msecs_to_jiffies(NFC_TIME_OUT_MS)))
+                       continue;       /* wait for next completion */
+               else
+                       goto err_timeout;
+       }
+
+       return 0;
+
+err_timeout:
+       dev_err(host->dev, "Time out to wait for interrupt: 0x%08x\n", flag);
+       /* Disable the interrupt as it is not handled by interrupt handler */
+       nfc_writel(host->nfc->hsmc_regs, IDR, flag);
+       return -ETIMEDOUT;
+}
+
+static int nfc_send_command(struct atmel_nand_host *host,
+       unsigned int cmd, unsigned int addr, unsigned char cycle0)
+{
+       unsigned long timeout;
+       u32 flag = NFC_SR_CMD_DONE;
+       flag |= cmd & NFCADDR_CMD_DATAEN ? NFC_SR_XFR_DONE : 0;
+
+       dev_dbg(host->dev,
+               "nfc_cmd: 0x%08x, addr1234: 0x%08x, cycle0: 0x%02x\n",
+               cmd, addr, cycle0);
+
+       timeout = jiffies + msecs_to_jiffies(NFC_TIME_OUT_MS);
+       while (nfc_readl(host->nfc->hsmc_regs, SR) & NFC_SR_BUSY) {
+               if (time_after(jiffies, timeout)) {
+                       dev_err(host->dev,
+                               "Time out to wait for NFC ready!\n");
+                       return -ETIMEDOUT;
+               }
+       }
+
+       nfc_prepare_interrupt(host, flag);
+       nfc_writel(host->nfc->hsmc_regs, CYCLE0, cycle0);
+       nfc_cmd_addr1234_writel(cmd, addr, host->nfc->base_cmd_regs);
+       return nfc_wait_interrupt(host, flag);
+}
+
+static int nfc_device_ready(struct mtd_info *mtd)
+{
+       u32 status, mask;
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+
+       status = nfc_read_status(host);
+       mask = nfc_readl(host->nfc->hsmc_regs, IMR);
+
+       /* The mask should be 0. If not we may lost interrupts */
+       if (unlikely(mask & status))
+               dev_err(host->dev, "Lost the interrupt flags: 0x%08x\n",
+                               mask & status);
+
+       return status & NFC_SR_RB_EDGE;
+}
+
+static void nfc_select_chip(struct mtd_info *mtd, int chip)
+{
+       struct nand_chip *nand_chip = mtd->priv;
+       struct atmel_nand_host *host = nand_chip->priv;
+
+       if (chip == -1)
+               nfc_writel(host->nfc->hsmc_regs, CTRL, NFC_CTRL_DISABLE);
+       else
+               nfc_writel(host->nfc->hsmc_regs, CTRL, NFC_CTRL_ENABLE);
+}
+
+static int nfc_make_addr(struct mtd_info *mtd, int command, int column,
+               int page_addr, unsigned int *addr1234, unsigned int *cycle0)
+{
+       struct nand_chip *chip = mtd->priv;
+
+       int acycle = 0;
+       unsigned char addr_bytes[8];
+       int index = 0, bit_shift;
+
+       BUG_ON(addr1234 == NULL || cycle0 == NULL);
+
+       *cycle0 = 0;
+       *addr1234 = 0;
+
+       if (column != -1) {
+               if (chip->options & NAND_BUSWIDTH_16 &&
+                               !nand_opcode_8bits(command))
+                       column >>= 1;
+               addr_bytes[acycle++] = column & 0xff;
+               if (mtd->writesize > 512)
+                       addr_bytes[acycle++] = (column >> 8) & 0xff;
+       }
+
+       if (page_addr != -1) {
+               addr_bytes[acycle++] = page_addr & 0xff;
+               addr_bytes[acycle++] = (page_addr >> 8) & 0xff;
+               if (chip->chipsize > (128 << 20))
+                       addr_bytes[acycle++] = (page_addr >> 16) & 0xff;
+       }
+
+       if (acycle > 4)
+               *cycle0 = addr_bytes[index++];
+
+       for (bit_shift = 0; index < acycle; bit_shift += 8)
+               *addr1234 += addr_bytes[index++] << bit_shift;
+
+       /* return acycle in cmd register */
+       return acycle << NFCADDR_CMD_ACYCLE_BIT_POS;
+}
+
+static void nfc_nand_command(struct mtd_info *mtd, unsigned int command,
+                               int column, int page_addr)
+{
+       struct nand_chip *chip = mtd->priv;
+       struct atmel_nand_host *host = chip->priv;
+       unsigned long timeout;
+       unsigned int nfc_addr_cmd = 0;
+
+       unsigned int cmd1 = command << NFCADDR_CMD_CMD1_BIT_POS;
+
+       /* Set default settings: no cmd2, no addr cycle. read from nand */
+       unsigned int cmd2 = 0;
+       unsigned int vcmd2 = 0;
+       int acycle = NFCADDR_CMD_ACYCLE_NONE;
+       int csid = NFCADDR_CMD_CSID_3;
+       int dataen = NFCADDR_CMD_DATADIS;
+       int nfcwr = NFCADDR_CMD_NFCRD;
+       unsigned int addr1234 = 0;
+       unsigned int cycle0 = 0;
+       bool do_addr = true;
+       host->nfc->data_in_sram = NULL;
+
+       dev_dbg(host->dev, "%s: cmd = 0x%02x, col = 0x%08x, page = 0x%08x\n",
+            __func__, command, column, page_addr);
+
+       switch (command) {
+       case NAND_CMD_RESET:
+               nfc_addr_cmd = cmd1 | acycle | csid | dataen | nfcwr;
+               nfc_send_command(host, nfc_addr_cmd, addr1234, cycle0);
+               udelay(chip->chip_delay);
+
+               nfc_nand_command(mtd, NAND_CMD_STATUS, -1, -1);
+               timeout = jiffies + msecs_to_jiffies(NFC_TIME_OUT_MS);
+               while (!(chip->read_byte(mtd) & NAND_STATUS_READY)) {
+                       if (time_after(jiffies, timeout)) {
+                               dev_err(host->dev,
+                                       "Time out to wait status ready!\n");
+                               break;
+                       }
+               }
+               return;
+       case NAND_CMD_STATUS:
+               do_addr = false;
+               break;
+       case NAND_CMD_PARAM:
+       case NAND_CMD_READID:
+               do_addr = false;
+               acycle = NFCADDR_CMD_ACYCLE_1;
+               if (column != -1)
+                       addr1234 = column;
+               break;
+       case NAND_CMD_RNDOUT:
+               cmd2 = NAND_CMD_RNDOUTSTART << NFCADDR_CMD_CMD2_BIT_POS;
+               vcmd2 = NFCADDR_CMD_VCMD2;
+               break;
+       case NAND_CMD_READ0:
+       case NAND_CMD_READOOB:
+               if (command == NAND_CMD_READOOB) {
+                       column += mtd->writesize;
+                       command = NAND_CMD_READ0; /* only READ0 is valid */
+                       cmd1 = command << NFCADDR_CMD_CMD1_BIT_POS;
+               }
+               if (host->nfc->use_nfc_sram) {
+                       /* Enable Data transfer to sram */
+                       dataen = NFCADDR_CMD_DATAEN;
+
+                       /* Need enable PMECC now, since NFC will transfer
+                        * data in bus after sending nfc read command.
+                        */
+                       if (chip->ecc.mode == NAND_ECC_HW && host->has_pmecc)
+                               pmecc_enable(host, NAND_ECC_READ);
+               }
+
+               cmd2 = NAND_CMD_READSTART << NFCADDR_CMD_CMD2_BIT_POS;
+               vcmd2 = NFCADDR_CMD_VCMD2;
+               break;
+       /* For prgramming command, the cmd need set to write enable */
+       case NAND_CMD_PAGEPROG:
+       case NAND_CMD_SEQIN:
+       case NAND_CMD_RNDIN:
+               nfcwr = NFCADDR_CMD_NFCWR;
+               if (host->nfc->will_write_sram && command == NAND_CMD_SEQIN)
+                       dataen = NFCADDR_CMD_DATAEN;
+               break;
+       default:
+               break;
+       }
+
+       if (do_addr)
+               acycle = nfc_make_addr(mtd, command, column, page_addr,
+                               &addr1234, &cycle0);
+
+       nfc_addr_cmd = cmd1 | cmd2 | vcmd2 | acycle | csid | dataen | nfcwr;
+       nfc_send_command(host, nfc_addr_cmd, addr1234, cycle0);
+
+       /*
+        * Program and erase have their own busy handlers status, sequential
+        * in, and deplete1 need no delay.
+        */
+       switch (command) {
+       case NAND_CMD_CACHEDPROG:
+       case NAND_CMD_PAGEPROG:
+       case NAND_CMD_ERASE1:
+       case NAND_CMD_ERASE2:
+       case NAND_CMD_RNDIN:
+       case NAND_CMD_STATUS:
+       case NAND_CMD_RNDOUT:
+       case NAND_CMD_SEQIN:
+       case NAND_CMD_READID:
+               return;
+
+       case NAND_CMD_READ0:
+               if (dataen == NFCADDR_CMD_DATAEN) {
+                       host->nfc->data_in_sram = host->nfc->sram_bank0 +
+                               nfc_get_sram_off(host);
+                       return;
+               }
+               /* fall through */
+       default:
+               nfc_prepare_interrupt(host, NFC_SR_RB_EDGE);
+               nfc_wait_interrupt(host, NFC_SR_RB_EDGE);
+       }
+}
+
+static int nfc_sram_write_page(struct mtd_info *mtd, struct nand_chip *chip,
+                       uint32_t offset, int data_len, const uint8_t *buf,
+                       int oob_required, int page, int cached, int raw)
+{
+       int cfg, len;
+       int status = 0;
+       struct atmel_nand_host *host = chip->priv;
+       void *sram = host->nfc->sram_bank0 + nfc_get_sram_off(host);
+
+       /* Subpage write is not supported */
+       if (offset || (data_len < mtd->writesize))
+               return -EINVAL;
+
+       len = mtd->writesize;
+       /* Copy page data to sram that will write to nand via NFC */
+       if (use_dma) {
+               if (atmel_nand_dma_op(mtd, (void *)buf, len, 0) != 0)
+                       /* Fall back to use cpu copy */
+                       memcpy(sram, buf, len);
+       } else {
+               memcpy(sram, buf, len);
+       }
+
+       cfg = nfc_readl(host->nfc->hsmc_regs, CFG);
+       if (unlikely(raw) && oob_required) {
+               memcpy(sram + len, chip->oob_poi, mtd->oobsize);
+               len += mtd->oobsize;
+               nfc_writel(host->nfc->hsmc_regs, CFG, cfg | NFC_CFG_WSPARE);
+       } else {
+               nfc_writel(host->nfc->hsmc_regs, CFG, cfg & ~NFC_CFG_WSPARE);
+       }
+
+       if (chip->ecc.mode == NAND_ECC_HW && host->has_pmecc)
+               /*
+                * When use NFC sram, need set up PMECC before send
+                * NAND_CMD_SEQIN command. Since when the nand command
+                * is sent, nfc will do transfer from sram and nand.
+                */
+               pmecc_enable(host, NAND_ECC_WRITE);
+
+       host->nfc->will_write_sram = true;
+       chip->cmdfunc(mtd, NAND_CMD_SEQIN, 0x00, page);
+       host->nfc->will_write_sram = false;
+
+       if (likely(!raw))
+               /* Need to write ecc into oob */
+               status = chip->ecc.write_page(mtd, chip, buf, oob_required);
+
+       if (status < 0)
+               return status;
+
+       chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);
+       status = chip->waitfunc(mtd, chip);
+
+       if ((status & NAND_STATUS_FAIL) && (chip->errstat))
+               status = chip->errstat(mtd, chip, FL_WRITING, status, page);
+
+       if (status & NAND_STATUS_FAIL)
+               return -EIO;
+
+       return 0;
+}
+
+static int nfc_sram_init(struct mtd_info *mtd)
+{
+       struct nand_chip *chip = mtd->priv;
+       struct atmel_nand_host *host = chip->priv;
+       int res = 0;
+
+       /* Initialize the NFC CFG register */
+       unsigned int cfg_nfc = 0;
+
+       /* set page size and oob layout */
+       switch (mtd->writesize) {
+       case 512:
+               cfg_nfc = NFC_CFG_PAGESIZE_512;
+               break;
+       case 1024:
+               cfg_nfc = NFC_CFG_PAGESIZE_1024;
+               break;
+       case 2048:
+               cfg_nfc = NFC_CFG_PAGESIZE_2048;
+               break;
+       case 4096:
+               cfg_nfc = NFC_CFG_PAGESIZE_4096;
+               break;
+       case 8192:
+               cfg_nfc = NFC_CFG_PAGESIZE_8192;
+               break;
+       default:
+               dev_err(host->dev, "Unsupported page size for NFC.\n");
+               res = -ENXIO;
+               return res;
+       }
+
+       /* oob bytes size = (NFCSPARESIZE + 1) * 4
+        * Max support spare size is 512 bytes. */
+       cfg_nfc |= (((mtd->oobsize / 4) - 1) << NFC_CFG_NFC_SPARESIZE_BIT_POS
+               & NFC_CFG_NFC_SPARESIZE);
+       /* default set a max timeout */
+       cfg_nfc |= NFC_CFG_RSPARE |
+                       NFC_CFG_NFC_DTOCYC | NFC_CFG_NFC_DTOMUL;
+
+       nfc_writel(host->nfc->hsmc_regs, CFG, cfg_nfc);
+
+       host->nfc->will_write_sram = false;
+       nfc_set_sram_bank(host, 0);
+
+       /* Use Write page with NFC SRAM only for PMECC or ECC NONE. */
+       if (host->nfc->write_by_sram) {
+               if ((chip->ecc.mode == NAND_ECC_HW && host->has_pmecc) ||
+                               chip->ecc.mode == NAND_ECC_NONE)
+                       chip->write_page = nfc_sram_write_page;
+               else
+                       host->nfc->write_by_sram = false;
+       }
+
+       dev_info(host->dev, "Using NFC Sram read %s\n",
+                       host->nfc->write_by_sram ? "and write" : "");
+       return 0;
+}
+
+static struct platform_driver atmel_nand_nfc_driver;
+/*
+ * Probe for the NAND device.
+ */
+static int atmel_nand_probe(struct platform_device *pdev)
+{
+       struct atmel_nand_host *host;
+       struct mtd_info *mtd;
+       struct nand_chip *nand_chip;
+       struct resource *mem;
+       struct mtd_part_parser_data ppdata = {};
+       int res, irq;
+
+       /* Allocate memory for the device structure (and zero it) */
+       host = devm_kzalloc(&pdev->dev, sizeof(*host), GFP_KERNEL);
+       if (!host)
+               return -ENOMEM;
+
+       res = platform_driver_register(&atmel_nand_nfc_driver);
+       if (res)
+               dev_err(&pdev->dev, "atmel_nand: can't register NFC driver\n");
+
+       mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       host->io_base = devm_ioremap_resource(&pdev->dev, mem);
+       if (IS_ERR(host->io_base)) {
+               res = PTR_ERR(host->io_base);
+               goto err_nand_ioremap;
+       }
+       host->io_phys = (dma_addr_t)mem->start;
+
+       mtd = &host->mtd;
+       nand_chip = &host->nand_chip;
+       host->dev = &pdev->dev;
+       if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) {
+               /* Only when CONFIG_OF is enabled of_node can be parsed */
+               res = atmel_of_init_port(host, pdev->dev.of_node);
+               if (res)
+                       goto err_nand_ioremap;
+       } else {
+               memcpy(&host->board, dev_get_platdata(&pdev->dev),
+                      sizeof(struct atmel_nand_data));
+       }
+
+       nand_chip->priv = host;         /* link the private data structures */
+       mtd->priv = nand_chip;
+       mtd->owner = THIS_MODULE;
+
+       /* Set address of NAND IO lines */
+       nand_chip->IO_ADDR_R = host->io_base;
+       nand_chip->IO_ADDR_W = host->io_base;
+
+       if (nand_nfc.is_initialized) {
+               /* NFC driver is probed and initialized */
+               host->nfc = &nand_nfc;
+
+               nand_chip->select_chip = nfc_select_chip;
+               nand_chip->dev_ready = nfc_device_ready;
+               nand_chip->cmdfunc = nfc_nand_command;
+
+               /* Initialize the interrupt for NFC */
+               irq = platform_get_irq(pdev, 0);
+               if (irq < 0) {
+                       dev_err(host->dev, "Cannot get HSMC irq!\n");
+                       res = irq;
+                       goto err_nand_ioremap;
+               }
+
+               res = devm_request_irq(&pdev->dev, irq, hsmc_interrupt,
+                               0, "hsmc", host);
+               if (res) {
+                       dev_err(&pdev->dev, "Unable to request HSMC irq %d\n",
+                               irq);
+                       goto err_nand_ioremap;
+               }
+       } else {
+               res = atmel_nand_set_enable_ready_pins(mtd);
+               if (res)
+                       goto err_nand_ioremap;
+
+               nand_chip->cmd_ctrl = atmel_nand_cmd_ctrl;
+       }
+
+       nand_chip->ecc.mode = host->board.ecc_mode;
+       nand_chip->chip_delay = 40;             /* 40us command delay time */
+
+       if (host->board.bus_width_16)   /* 16-bit bus width */
+               nand_chip->options |= NAND_BUSWIDTH_16;
+
+       nand_chip->read_buf = atmel_read_buf;
+       nand_chip->write_buf = atmel_write_buf;
+
+       platform_set_drvdata(pdev, host);
+       atmel_nand_enable(host);
+
+       if (gpio_is_valid(host->board.det_pin)) {
+               res = devm_gpio_request(&pdev->dev,
+                               host->board.det_pin, "nand_det");
+               if (res < 0) {
+                       dev_err(&pdev->dev,
+                               "can't request det gpio %d\n",
+                               host->board.det_pin);
+                       goto err_no_card;
+               }
+
+               res = gpio_direction_input(host->board.det_pin);
+               if (res < 0) {
+                       dev_err(&pdev->dev,
+                               "can't request input direction det gpio %d\n",
+                               host->board.det_pin);
+                       goto err_no_card;
+               }
+
+               if (gpio_get_value(host->board.det_pin)) {
+                       dev_info(&pdev->dev, "No SmartMedia card inserted.\n");
+                       res = -ENXIO;
+                       goto err_no_card;
+               }
+       }
+
+       if (host->board.on_flash_bbt || on_flash_bbt) {
+               dev_info(&pdev->dev, "Use On Flash BBT\n");
+               nand_chip->bbt_options |= NAND_BBT_USE_FLASH;
+       }
+
+       if (!host->board.has_dma)
+               use_dma = 0;
+
+       if (use_dma) {
+               dma_cap_mask_t mask;
+
+               dma_cap_zero(mask);
+               dma_cap_set(DMA_MEMCPY, mask);
+               host->dma_chan = dma_request_channel(mask, NULL, NULL);
+               if (!host->dma_chan) {
+                       dev_err(host->dev, "Failed to request DMA channel\n");
+                       use_dma = 0;
+               }
+       }
+       if (use_dma)
+               dev_info(host->dev, "Using %s for DMA transfers.\n",
+                                       dma_chan_name(host->dma_chan));
+       else
+               dev_info(host->dev, "No DMA support for NAND access.\n");
+
+       /* first scan to find the device and get the page size */
+       if (nand_scan_ident(mtd, 1, NULL)) {
+               res = -ENXIO;
+               goto err_scan_ident;
+       }
+
+       if (nand_chip->ecc.mode == NAND_ECC_HW) {
+               if (host->has_pmecc)
+                       res = atmel_pmecc_nand_init_params(pdev, host);
+               else
+                       res = atmel_hw_nand_init_params(pdev, host);
+
+               if (res != 0)
+                       goto err_hw_ecc;
+       }
+
+       /* initialize the nfc configuration register */
+       if (host->nfc && host->nfc->use_nfc_sram) {
+               res = nfc_sram_init(mtd);
+               if (res) {
+                       host->nfc->use_nfc_sram = false;
+                       dev_err(host->dev, "Disable use nfc sram for data transfer.\n");
+               }
+       }
+
+       /* second phase scan */
+       if (nand_scan_tail(mtd)) {
+               res = -ENXIO;
+               goto err_scan_tail;
+       }
+
+       mtd->name = "atmel_nand";
+       ppdata.of_node = pdev->dev.of_node;
+       res = mtd_device_parse_register(mtd, NULL, &ppdata,
+                       host->board.parts, host->board.num_parts);
+       if (!res)
+               return res;
+
+err_scan_tail:
+       if (host->has_pmecc && host->nand_chip.ecc.mode == NAND_ECC_HW)
+               pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DISABLE);
+err_hw_ecc:
+err_scan_ident:
+err_no_card:
+       atmel_nand_disable(host);
+       if (host->dma_chan)
+               dma_release_channel(host->dma_chan);
+err_nand_ioremap:
+       return res;
+}
+
+/*
+ * Remove a NAND device.
+ */
+static int atmel_nand_remove(struct platform_device *pdev)
+{
+       struct atmel_nand_host *host = platform_get_drvdata(pdev);
+       struct mtd_info *mtd = &host->mtd;
+
+       nand_release(mtd);
+
+       atmel_nand_disable(host);
+
+       if (host->has_pmecc && host->nand_chip.ecc.mode == NAND_ECC_HW) {
+               pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DISABLE);
+               pmerrloc_writel(host->pmerrloc_base, ELDIS,
+                               PMERRLOC_DISABLE);
+       }
+
+       if (host->dma_chan)
+               dma_release_channel(host->dma_chan);
+
+       platform_driver_unregister(&atmel_nand_nfc_driver);
+
+       return 0;
+}
+
+static struct atmel_nand_caps at91rm9200_caps = {
+       .pmecc_correct_erase_page = false,
+};
+
+static struct atmel_nand_caps sama5d4_caps = {
+       .pmecc_correct_erase_page = true,
+};
+
+static const struct of_device_id atmel_nand_dt_ids[] = {
+       { .compatible = "atmel,at91rm9200-nand", .data = &at91rm9200_caps },
+       { .compatible = "atmel,sama5d4-nand", .data = &sama5d4_caps },
+       { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, atmel_nand_dt_ids);
+
+static int atmel_nand_nfc_probe(struct platform_device *pdev)
+{
+       struct atmel_nfc *nfc = &nand_nfc;
+       struct resource *nfc_cmd_regs, *nfc_hsmc_regs, *nfc_sram;
+       int ret;
+
+       nfc_cmd_regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       nfc->base_cmd_regs = devm_ioremap_resource(&pdev->dev, nfc_cmd_regs);
+       if (IS_ERR(nfc->base_cmd_regs))
+               return PTR_ERR(nfc->base_cmd_regs);
+
+       nfc_hsmc_regs = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+       nfc->hsmc_regs = devm_ioremap_resource(&pdev->dev, nfc_hsmc_regs);
+       if (IS_ERR(nfc->hsmc_regs))
+               return PTR_ERR(nfc->hsmc_regs);
+
+       nfc_sram = platform_get_resource(pdev, IORESOURCE_MEM, 2);
+       if (nfc_sram) {
+               nfc->sram_bank0 = (void * __force)
+                               devm_ioremap_resource(&pdev->dev, nfc_sram);
+               if (IS_ERR(nfc->sram_bank0)) {
+                       dev_warn(&pdev->dev, "Fail to ioremap the NFC sram with error: %ld. So disable NFC sram.\n",
+                                       PTR_ERR(nfc->sram_bank0));
+               } else {
+                       nfc->use_nfc_sram = true;
+                       nfc->sram_bank0_phys = (dma_addr_t)nfc_sram->start;
+
+                       if (pdev->dev.of_node)
+                               nfc->write_by_sram = of_property_read_bool(
+                                               pdev->dev.of_node,
+                                               "atmel,write-by-sram");
+               }
+       }
+
+       nfc_writel(nfc->hsmc_regs, IDR, 0xffffffff);
+       nfc_readl(nfc->hsmc_regs, SR);  /* clear the NFC_SR */
+
+       nfc->clk = devm_clk_get(&pdev->dev, NULL);
+       if (!IS_ERR(nfc->clk)) {
+               ret = clk_prepare_enable(nfc->clk);
+               if (ret)
+                       return ret;
+       } else {
+               dev_warn(&pdev->dev, "NFC clock missing, update your Device Tree");
+       }
+
+       nfc->is_initialized = true;
+       dev_info(&pdev->dev, "NFC is probed.\n");
+
+       return 0;
+}
+
+static int atmel_nand_nfc_remove(struct platform_device *pdev)
+{
+       struct atmel_nfc *nfc = &nand_nfc;
+
+       if (!IS_ERR(nfc->clk))
+               clk_disable_unprepare(nfc->clk);
+
+       return 0;
+}
+
+static const struct of_device_id atmel_nand_nfc_match[] = {
+       { .compatible = "atmel,sama5d3-nfc" },
+       { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, atmel_nand_nfc_match);
+
+static struct platform_driver atmel_nand_nfc_driver = {
+       .driver = {
+               .name = "atmel_nand_nfc",
+               .of_match_table = of_match_ptr(atmel_nand_nfc_match),
+       },
+       .probe = atmel_nand_nfc_probe,
+       .remove = atmel_nand_nfc_remove,
+};
+
+static struct platform_driver atmel_nand_driver = {
+       .probe          = atmel_nand_probe,
+       .remove         = atmel_nand_remove,
+       .driver         = {
+               .name   = "atmel_nand",
+               .of_match_table = of_match_ptr(atmel_nand_dt_ids),
+       },
+};
+
+module_platform_driver(atmel_nand_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Rick Bronson");
+MODULE_DESCRIPTION("NAND/SmartMedia driver for AT91 / AVR32");
+MODULE_ALIAS("platform:atmel_nand");