mtd: nand: Fix writing mtdoops to nand flash.

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>

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 89b8583..e1596e5 100644 (file)
--- 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_info *mtd, loff_t to, size_t len,
                            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_info *mtd, loff_t to, size_t len,
        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;