linux-kernel - [PATCH v1 4/5] mtd: rawnand: meson: clear OOB buffer before read

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Message-ID: <20230412061700.1492474-5-AVKrasnov@sberdevices.ru>
Date:   Wed, 12 Apr 2023 09:16:58 +0300
From:   Arseniy Krasnov <AVKrasnov@...rdevices.ru>
To:     Liang Yang <liang.yang@...ogic.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Kevin Hilman <khilman@...libre.com>,
        Jerome Brunet <jbrunet@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Jianxin Pan <jianxin.pan@...ogic.com>,
        Yixun Lan <yixun.lan@...ogic.com>
CC:     <oxffffaa@...il.com>, <kernel@...rdevices.ru>,
        Arseniy Krasnov <AVKrasnov@...rdevices.ru>,
        <linux-mtd@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-amlogic@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v1 4/5] mtd: rawnand: meson: clear OOB buffer before read

This NAND reads only few user's bytes in ECC mode (not full OOB), so
fill OOB buffer with zeroes to not return garbage from previous reads
to user.
Otherwise 'nanddump' utility prints something like this for just erased
page:

...
0x000007f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
  OOB Data: ff ff ff ff 00 00 ff ff 80 cf 22 99 cb ad d3 be
  OOB Data: 63 27 ae 06 16 0a 2f eb bb dd 46 74 41 8e 88 6e
  OOB Data: 38 a1 2d e6 77 d4 05 06 f2 a5 7e 25 eb 34 7c ff
  OOB Data: 38 ea de 14 10 de 9b 40 33 16 6a cc 9d aa 2f 5e

Signed-off-by: Arseniy Krasnov <AVKrasnov@...rdevices.ru>
---
 drivers/mtd/nand/raw/meson_nand.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
index f84a10238e4d..f2f2472cb511 100644
--- a/drivers/mtd/nand/raw/meson_nand.c
+++ b/drivers/mtd/nand/raw/meson_nand.c
@@ -858,9 +858,12 @@ static int meson_nfc_read_page_sub(struct nand_chip *nand,
 static int meson_nfc_read_page_raw(struct nand_chip *nand, u8 *buf,
 				   int oob_required, int page)
 {
+	struct mtd_info *mtd = nand_to_mtd(nand);
 	u8 *oob_buf = nand->oob_poi;
 	int ret;
 
+	memset(oob_buf, 0, mtd->oobsize);
+
 	ret = meson_nfc_read_page_sub(nand, page, 1);
 	if (ret)
 		return ret;
@@ -881,6 +884,8 @@ static int meson_nfc_read_page_hwecc(struct nand_chip *nand, u8 *buf,
 	u8 *oob_buf = nand->oob_poi;
 	int ret, i;
 
+	memset(oob_buf, 0, mtd->oobsize);
+
 	ret = meson_nfc_read_page_sub(nand, page, 0);
 	if (ret)
 		return ret;
-- 
2.35.0