[PATCH] Fix writing mtdoops to nand flash.

From: motobud
Date: Mon Oct 30 2017 - 00:23:56 EST


From: Brent Taylor <motobud@xxxxxxxxx>

When mtdoops calls mtd_panic_write, it eventually calls
panic_nand_write in nand_base.c. In order to properly
wait for the nand chip to be ready in panic_nand_wait,
the chip must first be selected.

When using the atmel nand flash controller, a panic
would occur due to a NULL pointer exception.

Signed-off-by: Brent Taylor <motobud@xxxxxxxxx>
---
drivers/mtd/nand/nand_base.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 12edaae17d81..0a8058a66d93 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2802,9 +2802,14 @@ static int panic_nand_write(struct mtd_info *mtd, loff_t to, size_t len,
struct mtd_oob_ops ops;
int ret;

+ int chipnr = (int)(to >> chip->chip_shift);
+ chip->select_chip(mtd, chipnr);
+
/* Wait for the device to get ready */
panic_nand_wait(mtd, chip, 400);

+ chip->select_chip(mtd, -1);
+
/* Grab the device */
panic_nand_get_device(chip, mtd, FL_WRITING);

--
2.14.2