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Commit e0377cde authored by Aaron Sierra's avatar Aaron Sierra Committed by Brian Norris
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mtd: nand: Request strength instead of bytes for soft BCH 



Previously, we requested that drivers pass ecc.size and ecc.bytes when
using NAND_ECC_SOFT_BCH. However, a driver is likely to only know the ECC
strength required for its NAND, so each driver would need to perform a
strength-to-bytes calculation.

Avoid duplicating this calculation in each driver by asking drivers to
pass ecc.size and ecc.strength so that the strength-to-bytes calculation
need only be implemented once.

This reverts/generalizes this commit:
    mtd: nand: Base BCH ECC bytes on required strength

Signed-off-by: default avatarAaron Sierra <asierra@xes-inc.com>
Reviewed-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
parent 240181fd

drivers/mtd/nand/nand_base.c

+8 −6
Original line number Diff line number Diff line
@@ -4037,22 +4037,24 @@ int nand_scan_tail(struct mtd_info *mtd) 
		ecc->read_oob = nand_read_oob_std;

		ecc->write_oob = nand_write_oob_std;

		/*

		 * Board driver should supply ecc.size and ecc.bytes values to

		 * select how many bits are correctable; see nand_bch_init()

		 * for details. Otherwise, default to 4 bits for large page

		 * devices.

		 * Board driver should supply ecc.size and ecc.strength values

		 * to select how many bits are correctable. Otherwise, default

		 * to 4 bits for large page devices.

		 */

		if (!ecc->size && (mtd->oobsize >= 64)) {

			ecc->size = 512;

			ecc->bytes = DIV_ROUND_UP(13 * ecc->strength, 8);

			ecc->strength = 4;

		}



		/* See nand_bch_init() for details. */

		ecc->bytes = DIV_ROUND_UP(

				ecc->strength * fls(8 * ecc->size), 8);

		ecc->priv = nand_bch_init(mtd, ecc->size, ecc->bytes,

					       &ecc->layout);

		if (!ecc->priv) {

			pr_warn("BCH ECC initialization failed!\n");

			BUG();

		}

		ecc->strength = ecc->bytes * 8 / fls(8 * ecc->size);

		break;



	case NAND_ECC_NONE:

drivers/mtd/nand/nandsim.c

+1 −0
Original line number Diff line number Diff line
@@ -2337,6 +2337,7 @@ static int __init ns_init_module(void) 
		}

		chip->ecc.mode = NAND_ECC_SOFT_BCH;

		chip->ecc.size = 512;

		chip->ecc.strength = bch;

		chip->ecc.bytes = eccbytes;

		NS_INFO("using %u-bit/%u bytes BCH ECC\n", bch, chip->ecc.size);

	}

drivers/mtd/nand/sunxi_nand.c

+0 −2
Original line number Diff line number Diff line
@@ -1110,8 +1110,6 @@ static int sunxi_nand_ecc_init(struct mtd_info *mtd, struct nand_ecc_ctrl *ecc, 


	switch (ecc->mode) {

	case NAND_ECC_SOFT_BCH:

		ecc->bytes = DIV_ROUND_UP(ecc->strength * fls(8 * ecc->size),

					  8);

		break;

	case NAND_ECC_HW:

		ret = sunxi_nand_hw_ecc_ctrl_init(mtd, ecc, np);