From 84cfbbb85a98c8c89407f108da9d102e5dfe2ae5 Mon Sep 17 00:00:00 2001 From: Josh Wu Date: Wed, 23 Jan 2013 20:47:12 +0800 Subject: [PATCH] mtd: at91: atmel_nand: for PMECC, add code to check the ONFI parameter ECC requirement. 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 Signed-off-by: Artem Bityutskiy --- drivers/mtd/nand/atmel_nand.c | 90 +++++++++++++++++++++++++++++++++-- 1 file changed, 87 insertions(+), 3 deletions(-) diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c index f186a371e437..ffcbcca2fd2d 100644 --- a/drivers/mtd/nand/atmel_nand.c +++ b/drivers/mtd/nand/atmel_nand.c @@ -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, §or_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; -- 2.34.1