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c66d039197
linux/drivers/mtd/nand/omap2.c
Pekon Gupta c66d039197 mtd: nand: omap: combine different flavours of 1-bit hamming ecc schemes 
OMAP NAND driver currently supports multiple flavours of 1-bit Hamming
ecc-scheme, like:
- OMAP_ECC_HAMMING_CODE_DEFAULT
	1-bit hamming ecc code using software library
- OMAP_ECC_HAMMING_CODE_HW
	1-bit hamming ecc-code using GPMC h/w engine
- OMAP_ECC_HAMMING_CODE_HW_ROMCODE
	1-bit hamming ecc-code using GPMC h/w engin with ecc-layout compatible
	to ROM code.

This patch combines above multiple ecc-schemes into single implementation:
- OMAP_ECC_HAM1_CODE_HW
	1-bit hamming ecc-code using GPMC h/w engine with ROM-code compatible
	ecc-layout.

Signed-off-by: Pekon Gupta <pekon@ti.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
2013-11-06 23:33:07 -08:00

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/*
* 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>
#ifdef CONFIG_MTD_NAND_OMAP_BCH
#include <linux/bch.h>
#include <linux/platform_data/elm.h>
#endif
#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 BCH8_MAX_ERROR 8 /* upto 8 bit correctable */
#define BCH4_MAX_ERROR 4 /* upto 4 bit correctable */
#define SECTOR_BYTES 512
/* 4 bit padding to make byte aligned, 56 = 52 + 4 */
#define BCH4_BIT_PAD 4
#define BCH8_ECC_MAX ((SECTOR_BYTES + BCH8_ECC_OOB_BYTES) * 8)
#define BCH4_ECC_MAX ((SECTOR_BYTES + BCH4_ECC_OOB_BYTES) * 8)
/* 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 */
#ifdef CONFIG_MTD_NAND_OMAP_BCH
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};
#endif
/* oob info generated runtime depending on ecc algorithm and layout selected */
static struct nand_ecclayout omap_oobinfo;
/* Define some generic bad / good block scan pattern which are used
* while scanning a device for factory marked good / bad blocks
*/
static uint8_t scan_ff_pattern[] = { 0xff };
static struct nand_bbt_descr bb_descrip_flashbased = {
.options = NAND_BBT_SCANALLPAGES,
.offs = 0,
.len = 1,
.pattern = scan_ff_pattern,
};
struct omap_nand_info {
struct nand_hw_control controller;
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;
unsigned long mem_size;
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;
#ifdef CONFIG_MTD_NAND_OMAP_BCH
struct bch_control *bch;
struct nand_ecclayout ecclayout;
bool is_elm_used;
struct device *elm_dev;
struct device_node *of_node;
#endif
};
/**
* 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;
}
}
#ifdef CONFIG_MTD_NAND_OMAP_BCH
/**
* omap3_enable_hwecc_bch - Program OMAP3 GPMC to perform BCH ECC correction
* @mtd: MTD device structure
* @mode: Read/Write mode
*
* When using BCH, sector size is hardcoded to 512 bytes.
* Using wrapping mode 6 both for reading and writing if ELM module not uses
* for error correction.
* On writing,
* eccsize0 = 0 (no additional protected byte in spare area)
* eccsize1 = 32 (skip 32 nibbles = 16 bytes per sector in spare area)
*/
static void omap3_enable_hwecc_bch(struct mtd_info *mtd, int mode)
{
int nerrors;
unsigned int dev_width, nsectors;
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
struct nand_chip *chip = mtd->priv;
u32 val, wr_mode;
unsigned int ecc_size1, ecc_size0;
/* Using wrapping mode 6 for writing */
wr_mode = BCH_WRAPMODE_6;
/*
* ECC engine enabled for valid ecc_size0 nibbles
* and disabled for ecc_size1 nibbles.
*/
ecc_size0 = BCH_ECC_SIZE0;
ecc_size1 = BCH_ECC_SIZE1;
/* Perform ecc calculation on 512-byte sector */
nsectors = 1;
/* Update number of error correction */
nerrors = info->nand.ecc.strength;
/* Multi sector reading/writing for NAND flash with page size < 4096 */
if (info->is_elm_used && (mtd->writesize <= 4096)) {
if (mode == NAND_ECC_READ) {
/* Using wrapping mode 1 for reading */
wr_mode = BCH_WRAPMODE_1;
/*
* ECC engine enabled for ecc_size0 nibbles
* and disabled for ecc_size1 nibbles.
*/
ecc_size0 = (nerrors == 8) ?
BCH8R_ECC_SIZE0 : BCH4R_ECC_SIZE0;
ecc_size1 = (nerrors == 8) ?
BCH8R_ECC_SIZE1 : BCH4R_ECC_SIZE1;
}
/* Perform ecc calculation for one page (< 4096) */
nsectors = info->nand.ecc.steps;
}
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 */
(((nerrors == 8) ? 1 : 0) << 12) | /* 8 or 4 bits */
(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);
}
/**
* omap3_calculate_ecc_bch4 - Generate 7 bytes of ECC bytes
* @mtd: MTD device structure
* @dat: The pointer to data on which ecc is computed
* @ecc_code: The ecc_code buffer
*/
static int omap3_calculate_ecc_bch4(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);
unsigned long nsectors, val1, val2;
int i;
nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
for (i = 0; i < nsectors; i++) {
/* Read hw-computed remainder */
val1 = readl(info->reg.gpmc_bch_result0[i]);
val2 = readl(info->reg.gpmc_bch_result1[i]);
/*
* Add constant polynomial to remainder, in order to get an ecc
* sequence of 0xFFs for a buffer filled with 0xFFs; and
* left-justify the resulting polynomial.
*/
*ecc_code++ = 0x28 ^ ((val2 >> 12) & 0xFF);
*ecc_code++ = 0x13 ^ ((val2 >> 4) & 0xFF);
*ecc_code++ = 0xcc ^ (((val2 & 0xF) << 4)|((val1 >> 28) & 0xF));
*ecc_code++ = 0x39 ^ ((val1 >> 20) & 0xFF);
*ecc_code++ = 0x96 ^ ((val1 >> 12) & 0xFF);
*ecc_code++ = 0xac ^ ((val1 >> 4) & 0xFF);
*ecc_code++ = 0x7f ^ ((val1 & 0xF) << 4);
}
return 0;
}
/**
* omap3_calculate_ecc_bch8 - Generate 13 bytes of ECC bytes
* @mtd: MTD device structure
* @dat: The pointer to data on which ecc is computed
* @ecc_code: The ecc_code buffer
*/
static int omap3_calculate_ecc_bch8(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);
unsigned long nsectors, val1, val2, val3, val4;
int i;
nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
for (i = 0; i < nsectors; i++) {
/* Read hw-computed remainder */
val1 = readl(info->reg.gpmc_bch_result0[i]);
val2 = readl(info->reg.gpmc_bch_result1[i]);
val3 = readl(info->reg.gpmc_bch_result2[i]);
val4 = readl(info->reg.gpmc_bch_result3[i]);
/*
* Add constant polynomial to remainder, in order to get an ecc
* sequence of 0xFFs for a buffer filled with 0xFFs.
*/
*ecc_code++ = 0xef ^ (val4 & 0xFF);
*ecc_code++ = 0x51 ^ ((val3 >> 24) & 0xFF);
*ecc_code++ = 0x2e ^ ((val3 >> 16) & 0xFF);
*ecc_code++ = 0x09 ^ ((val3 >> 8) & 0xFF);
*ecc_code++ = 0xed ^ (val3 & 0xFF);
*ecc_code++ = 0x93 ^ ((val2 >> 24) & 0xFF);
*ecc_code++ = 0x9a ^ ((val2 >> 16) & 0xFF);
*ecc_code++ = 0xc2 ^ ((val2 >> 8) & 0xFF);
*ecc_code++ = 0x97 ^ (val2 & 0xFF);
*ecc_code++ = 0x79 ^ ((val1 >> 24) & 0xFF);
*ecc_code++ = 0xe5 ^ ((val1 >> 16) & 0xFF);
*ecc_code++ = 0x24 ^ ((val1 >> 8) & 0xFF);
*ecc_code++ = 0xb5 ^ (val1 & 0xFF);
}
return 0;
}
/**
* omap3_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 omap3_calculate_ecc_bch(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);
unsigned long nsectors, bch_val1, bch_val2, bch_val3, bch_val4;
int i, eccbchtsel;
nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
/*
* find BCH scheme used
* 0 -> BCH4
* 1 -> BCH8
*/
eccbchtsel = ((readl(info->reg.gpmc_ecc_config) >> 12) & 0x3);
for (i = 0; i < nsectors; i++) {
/* Read hw-computed remainder */
bch_val1 = readl(info->reg.gpmc_bch_result0[i]);
bch_val2 = readl(info->reg.gpmc_bch_result1[i]);
if (eccbchtsel) {
bch_val3 = readl(info->reg.gpmc_bch_result2[i]);
bch_val4 = readl(info->reg.gpmc_bch_result3[i]);
}
if (eccbchtsel) {
/* BCH8 ecc scheme */
*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);
/*
* Setting 14th byte to zero to handle
* erased page & maintain compatibility
* with RBL
*/
*ecc_code++ = 0x0;
} else {
/* BCH4 ecc scheme */
*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);
/*
* Setting 8th byte to zero to handle
* erased page
*/
*ecc_code++ = 0x0;
}
}
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 error/erased pages non-zero error vector is reported.
* In case of non-zero ecc vector, check read_ecc at fixed offset
* (x = 13/7 in case of BCH8/4 == 0) to find page programmed or not.
* To handle bit flips in this data, count the number of 0's in
* read_ecc[x] and check if it greater than 4. If it is less, it is
* programmed page, else erased page.
*
* 1. If page is erased, check with standard ecc vector (ecc vector
* for erased page to find any bit flip). If check fails, bit flip
* is present in erased page. Count the bit flips in erased page and
* if it falls under correctable level, report page with 0xFF and
* update the correctable bit information.
* 2. If error is reported on programmed page, update elm error
* vector and correct the page with ELM error correction routine.
*
*/
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);
int eccsteps = info->nand.ecc.steps;
int i , j, stat = 0;
int eccsize, eccflag, ecc_vector_size;
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;
enum bch_ecc type;
bool is_error_reported = false;
/* Initialize elm error vector to zero */
memset(err_vec, 0, sizeof(err_vec));
if (info->nand.ecc.strength == BCH8_MAX_ERROR) {
type = BCH8_ECC;
erased_ecc_vec = bch8_vector;
} else {
type = BCH4_ECC;
erased_ecc_vec = bch4_vector;
}
ecc_vector_size = info->nand.ecc.bytes;
/*
* Remove extra byte padding for BCH8 RBL
* compatibility and erased page handling
*/
eccsize = ecc_vector_size - 1;
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 < eccsize); j++) {
if (calc_ecc[j] != 0) {
eccflag = 1; /* non zero ecc, error present */
break;
}
}
if (eccflag == 1) {
/*
* Set threshold to minimum of 4, half of ecc.strength/2
* to allow max bit flip in byte to 4
*/
unsigned int threshold = min_t(unsigned int, 4,
info->nand.ecc.strength / 2);
/*
* Check data area is programmed by counting
* number of 0's at fixed offset in spare area.
* Checking count of 0's against threshold.
* In case programmed page expects at least threshold
* zeros in byte.
* If zeros are less than threshold for programmed page/
* zeros are more than threshold erased page, either
* case page reported as uncorrectable.
*/
if (hweight8(~read_ecc[eccsize]) >= threshold) {
/*
* Update elm error vector as
* data area is programmed
*/
err_vec[i].error_reported = true;
is_error_reported = true;
} else {
/* Error reported in erased page */
int bitflip_count;
u_char *buf = &data[info->nand.ecc.size * i];
if (memcmp(calc_ecc, erased_ecc_vec, eccsize)) {
bitflip_count = erased_sector_bitflips(
buf, read_ecc, info);
if (bitflip_count)
stat += bitflip_count;
else
return -EINVAL;
}
}
}
/* Update the ecc vector */
calc_ecc += ecc_vector_size;
read_ecc += ecc_vector_size;
}
/* Check if any error reported */
if (!is_error_reported)
return 0;
/* Decode BCH error using ELM module */
elm_decode_bch_error_page(info->elm_dev, ecc_vec, err_vec);
for (i = 0; i < eccsteps; i++) {
if (err_vec[i].error_reported) {
for (j = 0; j < err_vec[i].error_count; j++) {
u32 bit_pos, byte_pos, error_max, pos;
if (type == BCH8_ECC)
error_max = BCH8_ECC_MAX;
else
error_max = BCH4_ECC_MAX;
if (info->nand.ecc.strength == BCH8_MAX_ERROR)
pos = err_vec[i].error_loc[j];
else
/* Add 4 to take care 4 bit padding */
pos = err_vec[i].error_loc[j] +
BCH4_BIT_PAD;
/* 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)
data[byte_pos] ^= 1 << bit_pos;
else
spare_ecc[byte_pos - 512] ^=
1 << bit_pos;
}
/* else, not interested to correct ecc */
}
}
/* Update number of correctable errors */
stat += err_vec[i].error_count;
/* Update page data with sector size */
data += info->nand.ecc.size;
spare_ecc += ecc_vector_size;
}
for (i = 0; i < eccsteps; i++)
/* Return error if uncorrectable error present */
if (err_vec[i].error_uncorrectable)
return -EINVAL;
return stat;
}
/**
* omap3_correct_data_bch - Decode received data and correct errors
* @mtd: MTD device structure
* @data: page data
* @read_ecc: ecc read from nand flash
* @calc_ecc: ecc read from HW ECC registers
*/
static int omap3_correct_data_bch(struct mtd_info *mtd, u_char *data,
u_char *read_ecc, u_char *calc_ecc)
{
int i, count;
/* cannot correct more than 8 errors */
unsigned int errloc[8];
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
count = decode_bch(info->bch, NULL, 512, read_ecc, calc_ecc, NULL,
errloc);
if (count > 0) {
/* correct errors */
for (i = 0; i < count; i++) {
/* correct data only, not ecc bytes */
if (errloc[i] < 8*512)
data[errloc[i]/8] ^= 1 << (errloc[i] & 7);
pr_debug("corrected bitflip %u\n", errloc[i]);
}
} else if (count < 0) {
pr_err("ecc unrecoverable error\n");
}
return count;
}
/**
* 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;
}
/**
* omap3_free_bch - Release BCH ecc resources
* @mtd: MTD device structure
*/
static void omap3_free_bch(struct mtd_info *mtd)
{
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
if (info->bch) {
free_bch(info->bch);
info->bch = NULL;
}
}
/**
* omap3_init_bch - Initialize BCH ECC
* @mtd: MTD device structure
* @ecc_opt: OMAP ECC mode (OMAP_ECC_BCH4_CODE_HW or OMAP_ECC_BCH8_CODE_HW)
*/
static int omap3_init_bch(struct mtd_info *mtd, int ecc_opt)
{
int max_errors;
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
#ifdef CONFIG_MTD_NAND_OMAP_BCH8
const int hw_errors = BCH8_MAX_ERROR;
#else
const int hw_errors = BCH4_MAX_ERROR;
#endif
enum bch_ecc bch_type;
const __be32 *parp;
int lenp;
struct device_node *elm_node;
info->bch = NULL;
max_errors = (ecc_opt == OMAP_ECC_BCH8_CODE_HW) ?
BCH8_MAX_ERROR : BCH4_MAX_ERROR;
if (max_errors != hw_errors) {
pr_err("cannot configure %d-bit BCH ecc, only %d-bit supported",
max_errors, hw_errors);
goto fail;
}
info->nand.ecc.size = 512;
info->nand.ecc.hwctl = omap3_enable_hwecc_bch;
info->nand.ecc.mode = NAND_ECC_HW;
info->nand.ecc.strength = max_errors;
if (hw_errors == BCH8_MAX_ERROR)
bch_type = BCH8_ECC;
else
bch_type = BCH4_ECC;
/* Detect availability of ELM module */
parp = of_get_property(info->of_node, "elm_id", &lenp);
if ((parp == NULL) && (lenp != (sizeof(void *) * 2))) {
pr_err("Missing elm_id property, fall back to Software BCH\n");
info->is_elm_used = false;
} else {
struct platform_device *pdev;
elm_node = of_find_node_by_phandle(be32_to_cpup(parp));
pdev = of_find_device_by_node(elm_node);
info->elm_dev = &pdev->dev;
if (elm_config(info->elm_dev, bch_type) == 0)
info->is_elm_used = true;
}
if (info->is_elm_used && (mtd->writesize <= 4096)) {
if (hw_errors == BCH8_MAX_ERROR)
info->nand.ecc.bytes = BCH8_SIZE;
else
info->nand.ecc.bytes = BCH4_SIZE;
info->nand.ecc.correct = omap_elm_correct_data;
info->nand.ecc.calculate = omap3_calculate_ecc_bch;
info->nand.ecc.read_page = omap_read_page_bch;
info->nand.ecc.write_page = omap_write_page_bch;
} else {
/*
* software bch library is only used to detect and
* locate errors
*/
info->bch = init_bch(13, max_errors,
0x201b /* hw polynomial */);
if (!info->bch)
goto fail;
info->nand.ecc.correct = omap3_correct_data_bch;
/*
* The number of corrected errors in an ecc block that will
* trigger block scrubbing defaults to the ecc strength (4 or 8)
* Set mtd->bitflip_threshold here to define a custom threshold.
*/
if (max_errors == 8) {
info->nand.ecc.bytes = 13;
info->nand.ecc.calculate = omap3_calculate_ecc_bch8;
} else {
info->nand.ecc.bytes = 7;
info->nand.ecc.calculate = omap3_calculate_ecc_bch4;
}
}
pr_info("enabling NAND BCH ecc with %d-bit correction\n", max_errors);
return 0;
fail:
omap3_free_bch(mtd);
return -1;
}
/**
* omap3_init_bch_tail - Build an oob layout for BCH ECC correction.
* @mtd: MTD device structure
*/
static int omap3_init_bch_tail(struct mtd_info *mtd)
{
int i, steps, offset;
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
struct nand_ecclayout *layout = &info->ecclayout;
/* build oob layout */
steps = mtd->writesize/info->nand.ecc.size;
layout->eccbytes = steps*info->nand.ecc.bytes;
/* do not bother creating special oob layouts for small page devices */
if (mtd->oobsize < 64) {
pr_err("BCH ecc is not supported on small page devices\n");
goto fail;
}
/* reserve 2 bytes for bad block marker */
if (layout->eccbytes+2 > mtd->oobsize) {
pr_err("no oob layout available for oobsize %d eccbytes %u\n",
mtd->oobsize, layout->eccbytes);
goto fail;
}
/* ECC layout compatible with RBL for BCH8 */
if (info->is_elm_used && (info->nand.ecc.bytes == BCH8_SIZE))
offset = 2;
else
offset = mtd->oobsize - layout->eccbytes;
/* put ecc bytes at oob tail */
for (i = 0; i < layout->eccbytes; i++)
layout->eccpos[i] = offset + i;
if (info->is_elm_used && (info->nand.ecc.bytes == BCH8_SIZE))
layout->oobfree[0].offset = 2 + layout->eccbytes * steps;
else
layout->oobfree[0].offset = 2;
layout->oobfree[0].length = mtd->oobsize-2-layout->eccbytes;
info->nand.ecc.layout = layout;
if (!(info->nand.options & NAND_BUSWIDTH_16))
info->nand.badblock_pattern = &bb_descrip_flashbased;
return 0;
fail:
omap3_free_bch(mtd);
return -1;
}
#else
static int omap3_init_bch(struct mtd_info *mtd, int ecc_opt)
{
pr_err("CONFIG_MTD_NAND_OMAP_BCH is not enabled\n");
return -1;
}
static int omap3_init_bch_tail(struct mtd_info *mtd)
{
return -1;
}
static void omap3_free_bch(struct mtd_info *mtd)
{
}
#endif /* CONFIG_MTD_NAND_OMAP_BCH */
static int omap_nand_probe(struct platform_device *pdev)
{
struct omap_nand_info *info;
struct omap_nand_platform_data *pdata;
int err;
int i, offset;
dma_cap_mask_t mask;
unsigned sig;
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 = kzalloc(sizeof(struct omap_nand_info), GFP_KERNEL);
if (!info)
return -ENOMEM;
platform_set_drvdata(pdev, info);
spin_lock_init(&info->controller.lock);
init_waitqueue_head(&info->controller.wq);
info->pdev = pdev;
info->gpmc_cs = pdata->cs;
info->reg = pdata->reg;
info->mtd.priv = &info->nand;
info->mtd.name = dev_name(&pdev->dev);
info->mtd.owner = THIS_MODULE;
info->nand.options = pdata->devsize;
info->nand.options |= NAND_SKIP_BBTSCAN;
#ifdef CONFIG_MTD_NAND_OMAP_BCH
info->of_node = pdata->of_node;
#endif
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL) {
err = -EINVAL;
dev_err(&pdev->dev, "error getting memory resource\n");
goto out_free_info;
}
info->phys_base = res->start;
info->mem_size = resource_size(res);
if (!request_mem_region(info->phys_base, info->mem_size,
pdev->dev.driver->name)) {
err = -EBUSY;
goto out_free_info;
}
info->nand.IO_ADDR_R = ioremap(info->phys_base, info->mem_size);
if (!info->nand.IO_ADDR_R) {
err = -ENOMEM;
goto out_release_mem_region;
}
info->nand.controller = &info->controller;
info->nand.IO_ADDR_W = info->nand.IO_ADDR_R;
info->nand.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) {
info->nand.dev_ready = omap_dev_ready;
info->nand.chip_delay = 0;
} else {
info->nand.waitfunc = omap_wait;
info->nand.chip_delay = 50;
}
switch (pdata->xfer_type) {
case NAND_OMAP_PREFETCH_POLLED:
info->nand.read_buf = omap_read_buf_pref;
info->nand.write_buf = omap_write_buf_pref;
break;
case NAND_OMAP_POLLED:
if (info->nand.options & NAND_BUSWIDTH_16) {
info->nand.read_buf = omap_read_buf16;
info->nand.write_buf = omap_write_buf16;
} else {
info->nand.read_buf = omap_read_buf8;
info->nand.write_buf = omap_write_buf8;
}
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 out_release_mem_region;
} 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 out_release_mem_region;
}
info->nand.read_buf = omap_read_buf_dma_pref;
info->nand.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 out_release_mem_region;
}
err = request_irq(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 out_release_mem_region;
}
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 out_release_mem_region;
}
err = request_irq(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 out_release_mem_region;
}
info->nand.read_buf = omap_read_buf_irq_pref;
info->nand.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 out_release_mem_region;
}
/* select the ecc type */
if (pdata->ecc_opt == OMAP_ECC_HAM1_CODE_HW) {
info->nand.ecc.bytes = 3;
info->nand.ecc.size = 512;
info->nand.ecc.strength = 1;
info->nand.ecc.calculate = omap_calculate_ecc;
info->nand.ecc.hwctl = omap_enable_hwecc;
info->nand.ecc.correct = omap_correct_data;
info->nand.ecc.mode = NAND_ECC_HW;
} else if ((pdata->ecc_opt == OMAP_ECC_BCH4_CODE_HW) ||
(pdata->ecc_opt == OMAP_ECC_BCH8_CODE_HW)) {
err = omap3_init_bch(&info->mtd, pdata->ecc_opt);
if (err) {
err = -EINVAL;
goto out_release_mem_region;
}
}
/* DIP switches on some boards change between 8 and 16 bit
* bus widths for flash. Try the other width if the first try fails.
*/
if (nand_scan_ident(&info->mtd, 1, NULL)) {
info->nand.options ^= NAND_BUSWIDTH_16;
if (nand_scan_ident(&info->mtd, 1, NULL)) {
err = -ENXIO;
goto out_release_mem_region;
}
}
/* rom code layout */
if (pdata->ecc_opt == OMAP_ECC_HAM1_CODE_HW) {
if (info->nand.options & NAND_BUSWIDTH_16)
offset = 2;
else {
offset = 1;
info->nand.badblock_pattern = &bb_descrip_flashbased;
}
omap_oobinfo.eccbytes = 3 * (info->mtd.writesize / 512);
for (i = 0; i < omap_oobinfo.eccbytes; i++)
omap_oobinfo.eccpos[i] = i+offset;
omap_oobinfo.oobfree->offset = offset + omap_oobinfo.eccbytes;
omap_oobinfo.oobfree->length = info->mtd.oobsize -
(offset + omap_oobinfo.eccbytes);
info->nand.ecc.layout = &omap_oobinfo;
} else if ((pdata->ecc_opt == OMAP_ECC_BCH4_CODE_HW) ||
(pdata->ecc_opt == OMAP_ECC_BCH8_CODE_HW)) {
/* build OOB layout for BCH ECC correction */
err = omap3_init_bch_tail(&info->mtd);
if (err) {
err = -EINVAL;
goto out_release_mem_region;
}
}
/* second phase scan */
if (nand_scan_tail(&info->mtd)) {
err = -ENXIO;
goto out_release_mem_region;
}
ppdata.of_node = pdata->of_node;
mtd_device_parse_register(&info->mtd, NULL, &ppdata, pdata->parts,
pdata->nr_parts);
platform_set_drvdata(pdev, &info->mtd);
return 0;
out_release_mem_region:
if (info->dma)
dma_release_channel(info->dma);
if (info->gpmc_irq_count > 0)
free_irq(info->gpmc_irq_count, info);
if (info->gpmc_irq_fifo > 0)
free_irq(info->gpmc_irq_fifo, info);
release_mem_region(info->phys_base, info->mem_size);
out_free_info:
kfree(info);
return err;
}
static int omap_nand_remove(struct platform_device *pdev)
{
struct mtd_info *mtd = platform_get_drvdata(pdev);
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
omap3_free_bch(&info->mtd);
if (info->dma)
dma_release_channel(info->dma);
if (info->gpmc_irq_count > 0)
free_irq(info->gpmc_irq_count, info);
if (info->gpmc_irq_fifo > 0)
free_irq(info->gpmc_irq_fifo, info);
/* Release NAND device, its internal structures and partitions */
nand_release(&info->mtd);
iounmap(info->nand.IO_ADDR_R);
release_mem_region(info->phys_base, info->mem_size);
kfree(info);
return 0;
}
static struct platform_driver omap_nand_driver = {
.probe = omap_nand_probe,
.remove = omap_nand_remove,
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
},
};
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");
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