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: Aaron Sierra <asierra@xes-inc.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 3f24b58..f6af969 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -4037,22 +4037,24 @@
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: