[PATCH v2 10/10] mtd: rawnand: brcmnand: fix OOB R/W with Hamming ECC

[Linus Walleij]

From: Álvaro Fernández Rojas <noltari at gmail.com>

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 at gmail.com>
Acked-by: Brian Norris <computersforpeace at gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210224080210.23686-1-noltari@gmail.com
[Ported to U-Boot from the Linux kernel]
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
 drivers/mtd/nand/raw/brcmnand/brcmnand.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
index b2ebcaf7a5bf..efbf9a3120a4 100644
--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -2515,6 +2515,12 @@ static int brcmnand_init_cs(struct brcmnand_host *host, ofnode dn)
 	ret = nand_register(0, mtd);
 #endif /* __UBOOT__ */
 
+	/* 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;
 }
 
-- 
2.39.1