From: Tudor Ambarus <tudor.ambarus@microchip.com>
Date: Mon, 23 Mar 2020 19:50:40 +0200
Subject: mtd: spi-nor: Clear WEL bit when erase or program errors occur
Git-commit: e0fe5339d4886c48cdd68a2c49d602c4c1864c38
Patch-mainline: v5.7-rc1
References: jsc#SLE-14214 jsc#SLE-16606

When an Erase or Program error occurs on a spansion/cypress or a
micron flash, the WEL bit remains set to one and should be cleared
with a WRDI command in order to protect against inadvertent writes
that can possible corrupt the contents of the memory.

Winbond, macronix, gd, etc., do not support the E_ERR and P_ERR bits in the
Status Register and always clear the WEL bit regardless of the outcome
of the erase or page program operation (ex w25q40bw, MX25L25635E).

Issue a WRDI command when erase or page program errors occur.

Reported-by: John Garry <john.garry@huawei.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Tested-by: John Garry <john.garry@huawei.com>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>
---
 drivers/mtd/spi-nor/core.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 877557dbda7f..e0021dd34bfe 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -559,6 +559,17 @@ static int spi_nor_sr_ready(struct spi_nor *nor)
 			dev_err(nor->dev, "Programming Error occurred\n");
 
 		spi_nor_clear_sr(nor);
+
+		/*
+		 * WEL bit remains set to one when an erase or page program
+		 * error occurs. Issue a Write Disable command to protect
+		 * against inadvertent writes that can possibly corrupt the
+		 * contents of the memory.
+		 */
+		ret = spi_nor_write_disable(nor);
+		if (ret)
+			return ret;
+
 		return -EIO;
 	}
 
@@ -615,6 +626,17 @@ static int spi_nor_fsr_ready(struct spi_nor *nor)
 			"Attempted to modify a protected sector.\n");
 
 		spi_nor_clear_fsr(nor);
+
+		/*
+		 * WEL bit remains set to one when an erase or page program
+		 * error occurs. Issue a Write Disable command to protect
+		 * against inadvertent writes that can possibly corrupt the
+		 * contents of the memory.
+		 */
+		ret = spi_nor_write_disable(nor);
+		if (ret)
+			return ret;
+
 		return -EIO;
 	}
 
-- 
2.28.0