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mtd: at91: atmel_nand: for PMECC, add code to check the ONFI parameter ECC requirement.

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This patch will check NAND flash's ecc minimum requirement in ONFI parameter.

1. if pmecc-cap, pmecc-sector-size is set in dts. then use it. Driver will
   print out a WARNING if the values are different from ONFI parameters.
2. if pmecc-cap, pmecc-sector-size is not set in dts, then use the value
   from ONFI parameters.
    * If ONFI ECC parameters are in ONFI extended parameter page, since we are
      not support it, so assume the minimum ecc requirement is 2 bits in 512
      bytes.
    * For non-ONFI support nand flash, also assume the minimum ecc requirement is
      2 bits in 512 bytes.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
This commit is contained in:
Josh Wu 2013-01-23 20:47:12 +08:00 committed by Artem Bityutskiy
parent e66b4318f8
commit 84cfbbb85a
1 changed files with 87 additions and 3 deletions
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90
drivers/mtd/nand/atmel_nand.c
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@ -910,6 +910,84 @@ static void atmel_pmecc_core_init(struct mtd_info *mtd)
pmecc_writel(host->ecc, CTRL, PMECC_CTRL_ENABLE);
}
/*
* Get ECC requirement in ONFI parameters, returns -1 if ONFI
* parameters is not supported.
* return 0 if success to get the ECC requirement.
*/
static int get_onfi_ecc_param(struct nand_chip *chip,
int *ecc_bits, int *sector_size)
{
*ecc_bits = *sector_size = 0;
if (chip->onfi_params.ecc_bits == 0xff)
/* TODO: the sector_size and ecc_bits need to be find in
* extended ecc parameter, currently we don't support it.
*/
return -1;
*ecc_bits = chip->onfi_params.ecc_bits;
/* The default sector size (ecc codeword size) is 512 */
*sector_size = 512;
return 0;
}
/*
* Get ecc requirement from ONFI parameters ecc requirement.
* If pmecc-cap, pmecc-sector-size in DTS are not specified, this function
* will set them according to ONFI 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 ECC requirement from ONFI parameters */
*cap = *sector_size = 0;
if (host->nand_chip.onfi_version) {
if (!get_onfi_ecc_param(&host->nand_chip, cap, sector_size))
dev_info(host->dev, "ONFI params, minimum required ECC: %d bits in %d bytes\n",
*cap, *sector_size);
else
dev_info(host->dev, "NAND chip ECC reqirement is in Extended ONFI parameter, we don't support yet.\n");
} else {
dev_info(host->dev, "NAND chip is not ONFI compliant, assume ecc_bits is 2 in 512 bytes");
}
if (*cap == 0 && *sector_size == 0) {
*cap = 2;
*sector_size = 512;
}
/* If dts file doesn't specify then use the one in ONFI 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 int __init atmel_pmecc_nand_init_params(struct platform_device *pdev,
struct atmel_nand_host *host)
{
@ -918,9 +996,15 @@ static int __init atmel_pmecc_nand_init_params(struct platform_device *pdev,
struct resource *regs, *regs_pmerr, *regs_rom;
int cap, sector_size, err_no;
if (host->pmecc_corr_cap == 0 || host->pmecc_sector_size == 0)
/* TODO: Should use ONFI ecc parameters. */
return -EINVAL;
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;