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mtd: nand: Fix writing mtdoops to nand flash

PATCH In review [email protected] 2 participants 2 messages Nov 28, 2017

Subsystems (3)
Stable branch Memory technology devices (MTD) NAND flash
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PATCH 1/1 mtd: nand: Fix writing mtdoops to nand flash

From: Brent Taylor <[email protected]>

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")
Cc <[email protected]> # 4.4.x
Cc <[email protected]> # 3.18.x
Signed-off-by Brent Taylor <[email protected]>
---
 drivers/mtd/nand/nand_base.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
drivers/mtd/nand/nand_base.c +6 -3
index 5b5c62712814..f0b95212c6b7 100644
@@ -2501,15 +2501,18 @@ 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;
 
-	/* 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;
Signature · 1 line
2.15.0
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#1 lore raw
Quoted 9 lines · On Mon, Nov 27, 2017 at 11:59:14PM -0600, [email protected] wrote:

From: Brent Taylor <[email protected]>

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.

Quoted 5 lines

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")
Cc <[email protected]> # 4.4.x

This does not apply to the 4.4.x tree at all, only 3.18.x. Can you provide a backport for 4.4.x as well?

thanks,

greg k-h