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Commit 8bbba481 authored by Boris Brezillon's avatar Boris Brezillon
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mtd: nand: Support maximizing ECC when using software BCH 



Add support for ECC maximization when software BCH with
nand_ooblayout_lp_ops layout is used.
Other cases should be handled by the NAND controller driver.

Signed-off-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
parent ba78ee00

drivers/mtd/nand/nand_base.c

+20 −0
Original line number Diff line number Diff line
@@ -4396,6 +4396,7 @@ static int nand_set_ecc_soft_ops(struct mtd_info *mtd) 
		ecc->write_page_raw = nand_write_page_raw;

		ecc->read_oob = nand_read_oob_std;

		ecc->write_oob = nand_write_oob_std;



		/*

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

		* values to select how many bits are correctable.
@@ -4418,6 +4419,25 @@ static int nand_set_ecc_soft_ops(struct mtd_info *mtd) 
			}



			mtd_set_ooblayout(mtd, &nand_ooblayout_lp_ops);



		}



		/*

		 * We can only maximize ECC config when the default layout is

		 * used, otherwise we don't know how many bytes can really be

		 * used.

		 */

		if (mtd->ooblayout == &nand_ooblayout_lp_ops &&

		    ecc->options & NAND_ECC_MAXIMIZE) {

			int steps, bytes;



			/* Always prefer 1k blocks over 512bytes ones */

			ecc->size = 1024;

			steps = mtd->writesize / ecc->size;



			/* Reserve 2 bytes for the BBM */

			bytes = (mtd->oobsize - 2) / steps;

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

		}



		/* See nand_bch_init() for details. */