From dcb351c03f2fa6a599de1061b174167e03ee312b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Fern=C3=A1ndez=20Rojas?= <noltari@gmail.com>
Date: Tue, 12 May 2020 10:24:51 +0200
Subject: [PATCH] mtd: rawnand: brcmnand: correctly verify erased pages
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Git-commit: dcb351c03f2fa6a599de1061b174167e03ee312b
Patch-mainline: v5.8-rc1
References: git-fixes

The current code checks that the whole OOB area is erased.
This is a problem when JFFS2 cleanmarkers are added to the OOB, since it will
fail due to the usable OOB bytes not being 0xff.
Correct this by only checking that data and ECC bytes aren't 0xff.

Fixes: 02b88eea9f9c ("mtd: brcmnand: Add check for erased page bitflips")
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200512082451.771212-1-noltari@gmail.com
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/mtd/nand/raw/brcmnand/brcmnand.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
index ede7cb95fe71..30a9a8dbcc05 100644
--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -2017,28 +2017,31 @@ static int brcmnand_read_by_pio(struct mtd_info *mtd, struct nand_chip *chip,
 static int brcmstb_nand_verify_erased_page(struct mtd_info *mtd,
 		  struct nand_chip *chip, void *buf, u64 addr)
 {
-	int i, sas;
-	void *oob = chip->oob_poi;
+	struct mtd_oob_region ecc;
+	int i;
 	int bitflips = 0;
 	int page = addr >> chip->page_shift;
 	int ret;
+	void *ecc_bytes;
 	void *ecc_chunk;
 
 	if (!buf)
 		buf = nand_get_data_buf(chip);
 
-	sas = mtd->oobsize / chip->ecc.steps;
-
 	/* read without ecc for verification */
 	ret = chip->ecc.read_page_raw(chip, buf, true, page);
 	if (ret)
 		return ret;
 
-	for (i = 0; i < chip->ecc.steps; i++, oob += sas) {
+	for (i = 0; i < chip->ecc.steps; i++) {
 		ecc_chunk = buf + chip->ecc.size * i;
-		ret = nand_check_erased_ecc_chunk(ecc_chunk,
-						  chip->ecc.size,
-						  oob, sas, NULL, 0,
+
+		mtd_ooblayout_ecc(mtd, i, &ecc);
+		ecc_bytes = chip->oob_poi + ecc.offset;
+
+		ret = nand_check_erased_ecc_chunk(ecc_chunk, chip->ecc.size,
+						  ecc_bytes, ecc.length,
+						  NULL, 0,
 						  chip->ecc.strength);
 		if (ret < 0)
 			return ret;
-- 
2.16.4