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Commit 84cfbbb8 authored by Josh Wu's avatar Josh Wu Committed by Artem Bityutskiy
Browse files

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: default avatarJosh Wu <josh.wu@atmel.com>
Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
parent e66b4318

drivers/mtd/nand/atmel_nand.c

+87 −3
Original line number Diff line number Diff line
@@ -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;