[PATCH 3.2 23/79] mtd: nand: Fix writing mtdoops to nand flash.

Ben Hutchings
2018-02-11T04:20:06Z

From: Brent Taylor <motobud@gmail.com>

commit 30863e38ebeb500a31cecee8096fb5002677dd9b upstream.

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.

Fixes: 2af7c6539931 ("mtd: Add panic_write for NAND flashes")
Signed-off-by: Brent Taylor <motobud@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/mtd/nand/nand_base.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2290,6 +2290,7 @@ static int panic_nand_write(struct mtd_i
size_t *retlen, const uint8_t *buf)
{
struct nand_chip *chip = mtd->priv;
+ int chipnr = (int)(to >> chip->chip_shift);
struct mtd_oob_ops ops;
int ret;

@@ -2299,12 +2300,14 @@ static int panic_nand_write(struct mtd_i
if (!len)
return 0;

- /* Wait for the device to get ready */
- panic_nand_wait(mtd, chip, 400);
-
/* Grab the device */
panic_nand_get_device(chip, mtd, FL_WRITING);

+ chip->select_chip(mtd, chipnr);
+
+ /* Wait for the device to get ready */
+ panic_nand_wait(mtd, chip, 400);
+
ops.len = len;
ops.datbuf = (uint8_t *)buf;
ops.oobbuf = NULL;