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mtd: nand: omap: clean-up ecc layout for BCH ecc schemes 

In current implementation omap3_init_bch_tail() is a common function to
define ecc layout for different BCHx ecc schemes.This patch:
(1) removes omap3_init_bch_tail() and defines ecc layout for individual
    ecc-schemes along with populating their nand_chip->ecc data in
    omap_nand_probe(). This improves the readability and scalability of
    code for add new ecc schemes in future.
(2) removes 'struct nand_bbt_descr bb_descrip_flashbased' because default
    nand_bbt_descr in nand_bbt.c matches the same (.len=1 for x8 devices).
(3) add the check to see if NAND device has enough OOB/Spare bytes to
    store ECC signature of whole page, as defined by ecc-scheme.

Signed-off-by: Pekon Gupta <pekon@ti.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
This commit is contained in:
Pekon Gupta 2013-10-24 18:20:22 +05:30 committed by Brian Norris
parent a919e51161
commit b491da7233
1 changed files with 62 additions and 99 deletions
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161
drivers/mtd/nand/omap2.c
View File

@ -139,6 +139,7 @@
#define BCH_ECC_SIZE0 0x0 /* ecc_size0 = 0, no oob protection */
#define BCH_ECC_SIZE1 0x20 /* ecc_size1 = 32 */
#define BADBLOCK_MARKER_LENGTH 2
#define OMAP_ECC_BCH8_POLYNOMIAL 0x201b
#ifdef CONFIG_MTD_NAND_OMAP_BCH
@ -149,17 +150,6 @@ static u_char bch4_vector[] = {0x00, 0x6b, 0x31, 0xdd, 0x41, 0xbc, 0x10};
/* 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;
@ -184,7 +174,6 @@ struct omap_nand_info {
struct gpmc_nand_regs reg;
/* fields specific for BCHx_HW ECC scheme */
struct bch_control *bch;
struct nand_ecclayout ecclayout;
bool is_elm_used;
struct device *elm_dev;
struct device_node *of_node;
@ -1686,65 +1675,8 @@ static void omap3_free_bch(struct mtd_info *mtd)
}
}
/**
* 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_tail(struct mtd_info *mtd)
{
return -1;
}
static void omap3_free_bch(struct mtd_info *mtd)
{
}
@ -1756,8 +1688,9 @@ static int omap_nand_probe(struct platform_device *pdev)
struct omap_nand_platform_data *pdata;
struct mtd_info *mtd;
struct nand_chip *nand_chip;
struct nand_ecclayout *ecclayout;
int err;
int i, offset;
int i;
dma_cap_mask_t mask;
unsigned sig;
struct resource *res;
@ -1840,6 +1773,13 @@ static int omap_nand_probe(struct platform_device *pdev)
goto out_release_mem_region;
}
/* check for small page devices */
if ((mtd->oobsize < 64) && (pdata->ecc_opt != OMAP_ECC_HAM1_CODE_HW)) {
pr_err("small page devices are not supported\n");
err = -EINVAL;
goto out_release_mem_region;
}
/* re-populate low-level callbacks based on xfer modes */
switch (pdata->xfer_type) {
case NAND_OMAP_PREFETCH_POLLED:
@ -1931,6 +1871,8 @@ static int omap_nand_probe(struct platform_device *pdev)
}
/* populate MTD interface based on ECC scheme */
nand_chip->ecc.layout = &omap_oobinfo;
ecclayout = &omap_oobinfo;
switch (pdata->ecc_opt) {
case OMAP_ECC_HAM1_CODE_HW:
pr_info("nand: using OMAP_ECC_HAM1_CODE_HW\n");
@ -1941,6 +1883,16 @@ static int omap_nand_probe(struct platform_device *pdev)
nand_chip->ecc.calculate = omap_calculate_ecc;
nand_chip->ecc.hwctl = omap_enable_hwecc;
nand_chip->ecc.correct = omap_correct_data;
/* define ECC layout */
ecclayout->eccbytes = nand_chip->ecc.bytes *
(mtd->writesize /
nand_chip->ecc.size);
if (nand_chip->options & NAND_BUSWIDTH_16)
ecclayout->eccpos[0] = BADBLOCK_MARKER_LENGTH;
else
ecclayout->eccpos[0] = 1;
ecclayout->oobfree->offset = ecclayout->eccpos[0] +
ecclayout->eccbytes;
break;
case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
@ -1953,6 +1905,13 @@ static int omap_nand_probe(struct platform_device *pdev)
nand_chip->ecc.hwctl = omap3_enable_hwecc_bch;
nand_chip->ecc.correct = omap3_correct_data_bch;
nand_chip->ecc.calculate = omap3_calculate_ecc_bch4;
/* define ECC layout */
ecclayout->eccbytes = nand_chip->ecc.bytes *
(mtd->writesize /
nand_chip->ecc.size);
ecclayout->eccpos[0] = BADBLOCK_MARKER_LENGTH;
ecclayout->oobfree->offset = ecclayout->eccpos[0] +
ecclayout->eccbytes;
/* software bch library is used for locating errors */
info->bch = init_bch(nand_chip->ecc.bytes,
nand_chip->ecc.strength,
@ -1981,6 +1940,13 @@ static int omap_nand_probe(struct platform_device *pdev)
nand_chip->ecc.calculate = omap3_calculate_ecc_bch;
nand_chip->ecc.read_page = omap_read_page_bch;
nand_chip->ecc.write_page = omap_write_page_bch;
/* define ECC layout */
ecclayout->eccbytes = nand_chip->ecc.bytes *
(mtd->writesize /
nand_chip->ecc.size);
ecclayout->eccpos[0] = BADBLOCK_MARKER_LENGTH;
ecclayout->oobfree->offset = ecclayout->eccpos[0] +
ecclayout->eccbytes;
/* This ECC scheme requires ELM H/W block */
if (is_elm_present(info, pdata->elm_of_node, BCH4_ECC) < 0) {
pr_err("nand: error: could not initialize ELM\n");
@ -2004,6 +1970,13 @@ static int omap_nand_probe(struct platform_device *pdev)
nand_chip->ecc.hwctl = omap3_enable_hwecc_bch;
nand_chip->ecc.correct = omap3_correct_data_bch;
nand_chip->ecc.calculate = omap3_calculate_ecc_bch8;
/* define ECC layout */
ecclayout->eccbytes = nand_chip->ecc.bytes *
(mtd->writesize /
nand_chip->ecc.size);
ecclayout->eccpos[0] = BADBLOCK_MARKER_LENGTH;
ecclayout->oobfree->offset = ecclayout->eccpos[0] +
ecclayout->eccbytes;
/* software bch library is used for locating errors */
info->bch = init_bch(nand_chip->ecc.bytes,
nand_chip->ecc.strength,
@ -2038,6 +2011,13 @@ static int omap_nand_probe(struct platform_device *pdev)
pr_err("nand: error: could not initialize ELM\n");
goto out_release_mem_region;
}
/* define ECC layout */
ecclayout->eccbytes = nand_chip->ecc.bytes *
(mtd->writesize /
nand_chip->ecc.size);
ecclayout->eccpos[0] = BADBLOCK_MARKER_LENGTH;
ecclayout->oobfree->offset = ecclayout->eccpos[0] +
ecclayout->eccbytes;
break;
#else
pr_err("nand: error: CONFIG_MTD_NAND_OMAP_BCH not enabled\n");
@ -2051,34 +2031,17 @@ static int omap_nand_probe(struct platform_device *pdev)
goto out_release_mem_region;
}
/* rom code layout */
if (pdata->ecc_opt == OMAP_ECC_HAM1_CODE_HW) {
if (nand_chip->options & NAND_BUSWIDTH_16) {
offset = 2;
} else {
offset = 1;
nand_chip->badblock_pattern = &bb_descrip_flashbased;
}
omap_oobinfo.eccbytes = 3 * (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 = mtd->oobsize -
(offset + omap_oobinfo.eccbytes);
nand_chip->ecc.layout = &omap_oobinfo;
} else if ((pdata->ecc_opt == OMAP_ECC_BCH4_CODE_HW) ||
(pdata->ecc_opt == OMAP_ECC_BCH4_CODE_HW_DETECTION_SW) ||
(pdata->ecc_opt == OMAP_ECC_BCH8_CODE_HW_DETECTION_SW) ||
(pdata->ecc_opt == OMAP_ECC_BCH8_CODE_HW)) {
/* build OOB layout for BCH ECC correction */
err = omap3_init_bch_tail(mtd);
if (err) {
err = -EINVAL;
goto out_release_mem_region;
}
/* populate remaining ECC layout data */
ecclayout->oobfree->length = mtd->oobsize - (BADBLOCK_MARKER_LENGTH +
ecclayout->eccbytes);
for (i = 1; i < ecclayout->eccbytes; i++)
ecclayout->eccpos[i] = ecclayout->eccpos[0] + i;
/* check if NAND device's OOB is enough to store ECC signatures */
if (mtd->oobsize < (ecclayout->eccbytes + BADBLOCK_MARKER_LENGTH)) {
pr_err("not enough OOB bytes required = %d, available=%d\n",
ecclayout->eccbytes, mtd->oobsize);
err = -EINVAL;
goto out_release_mem_region;
}
/* second phase scan */