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

[Arseniy Krasnov]

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 at sberdevices.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