openwrt/target/linux/bcm63xx/patches-5.4/434-nand-brcmnand-fix-OOB-R-W-with-Hamming-ECC.patch

From cf0d2fbaae9e962d91a321de75e0d4f9f9ccbdfe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Fern=C3=A1ndez=20Rojas?= <noltari@gmail.com>
Date: Thu, 21 Jan 2021 18:17:37 +0100
Subject: [PATCH] nand: brcmnand: fix OOB R/W with Hamming ECC
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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. When 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.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
 drivers/mtd/nand/raw/brcmnand/brcmnand.c | 6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -2426,6 +2426,12 @@ static int brcmnand_attach_chip(struct n
 
 	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;
 }