Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Chen-Tsung Hsieh <chentsung@chromium.org>
To:     Tudor Ambarus <tudor.ambarus@microchip.com>,
        Pratyush Yadav <p.yadav@ti.com>,
        Michael Walle <michael@walle.cc>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>
Cc:     linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
        Chen-Tsung Hsieh <chentsung@chromium.org>
Subject: [RESEND PATCH] mtd: spi-nor: core: Check written SR value in spi_nor_write_16bit_sr_and_check()
Date:   Wed, 26 Jan 2022 15:32:26 +0800
Message-Id: <20220126073227.3401275-1-chentsung@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Read back Status Register 1 to ensure that the written byte match the
received value and return -EIO if read back test failed.

Without this patch, spi_nor_write_16bit_sr_and_check() only check the
second half of the 16bit. It causes errors like spi_nor_sr_unlock()
return success incorrectly when spi_nor_write_16bit_sr_and_check()
doesn't write SR successfully.

Fixes: 39d1e3340c73 ("mtd: spi-nor: Fix clearing of QE bit on lock()/unlock()")
Signed-off-by: Chen-Tsung Hsieh <chentsung@chromium.org>
---

 drivers/mtd/spi-nor/core.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 04ea180118e3..426bfa9a65f4 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -1007,6 +1007,15 @@ static int spi_nor_write_16bit_sr_and_check(struct spi_nor *nor, u8 sr1)
 	if (ret)
 		return ret;
 
+	ret = spi_nor_read_sr(nor, sr_cr);
+	if (ret)
+		return ret;
+
+	if (sr1 != sr_cr[0]) {
+		dev_dbg(nor->dev, "SR: Read back test failed\n");
+		return -EIO;
+	}
+
 	if (nor->flags & SNOR_F_NO_READ_CR)
 		return 0;
 
-- 
2.35.0.rc0.227.g00780c9af4-goog
Resend patch to move maintainers from 'Cc' to 'To' list.