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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: Boris Brezillon <boris.brezillon@free-electrons.com>
This commit is contained in:
Boris Brezillon 2016-06-08 17:04:23 +02:00
parent ba78ee00e1
commit 8bbba48124
1 changed files with 20 additions and 0 deletions
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20
drivers/mtd/nand/nand_base.c
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@ -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. */