mtd: rawnand: brcmnand: fix OOB R/W with Hamming ECC

[ Upstream commit f5200c14242fb8fa4a9b93f7fd4064d237e58785 ]

Hamming ECC doesn't cover the OOB data, so reading or writing OOB shall
always be done without ECC enabled.
This is a problem when adding JFFS2 cleanmarkers to erased blocks. If JFFS2
clenmarkers are added to the OOB with ECC enabled, OOB bytes will be changed
from ff ff ff to 00 00 00, reporting incorrect ECC errors.

Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller")
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210224080210.23686-1-noltari@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
index 2da39ab892869a6191490aff48b0ceeec60d3a46..909b14cc8e55cf880ebd0e040774e85a7102161c 100644 (file)
--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -2688,6 +2688,12 @@ static int brcmnand_attach_chip(struct nand_chip *chip)
 
        ret = brcmstb_choose_ecc_layout(host);
 
+       /* If OOB is written with ECC enabled it will cause ECC errors */
+       if (is_hamming_ecc(host->ctrl, &host->hwcfg)) {
+               chip->ecc.write_oob = brcmnand_write_oob_raw;
+               chip->ecc.read_oob = brcmnand_read_oob_raw;
+       }
+
        return ret;
 }