This is a note to let you know that I've just added the patch titled
mtd: nand: fix NAND_BUSWIDTH_AUTO for x16 devices
to the 3.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mtd-nand-fix-nand_buswidth_auto-for-x16-devices.patch
and it can be found in the queue-3.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 68e8078072e802e77134664f11d2ffbfbd2f8fbe Mon Sep 17 00:00:00 2001
From: Brian Norris <computersforpeace@xxxxxxxxx>
Date: Thu, 18 Jul 2013 01:17:02 -0700
Subject: mtd: nand: fix NAND_BUSWIDTH_AUTO for x16 devices
From: Brian Norris <computersforpeace@xxxxxxxxx>
commit 68e8078072e802e77134664f11d2ffbfbd2f8fbe upstream.
The code for NAND_BUSWIDTH_AUTO is broken. According to Alexander:
"I have a problem with attach NAND UBI in 16 bit mode.
NAND works fine if I specify NAND_BUSWIDTH_16 option, but not
working with NAND_BUSWIDTH_AUTO option. In second case NAND
chip is identifyed with ONFI."
See his report for the rest of the details:
http://lists.infradead.org/pipermail/linux-mtd/2013-July/047515.html
Anyway, the problem is that nand_set_defaults() is called twice, we
intend it to reset the chip functions to their x16 buswidth verions
if the buswidth changed from x8 to x16; however, nand_set_defaults()
does exactly nothing if called a second time.
Fix this by hacking nand_set_defaults() to reset the buswidth-dependent
functions if they were set to the x8 version the first time. Note that
this does not do anything to reset from x16 to x8, but that's not the
supported use case for NAND_BUSWIDTH_AUTO anyway.
Signed-off-by: Brian Norris <computersforpeace@xxxxxxxxx>
Reported-by: Alexander Shiyan <shc_work@xxxxxxx>
Tested-by: Alexander Shiyan <shc_work@xxxxxxx>
Cc: Matthieu Castet <matthieu.castet@xxxxxxxxxx>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>
Signed-off-by: David Woodhouse <David.Woodhouse@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/mtd/nand/nand_base.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2793,7 +2793,9 @@ static void nand_set_defaults(struct nan
if (!chip->select_chip)
chip->select_chip = nand_select_chip;
- if (!chip->read_byte)
+
+ /* If called twice, pointers that depend on busw may need to be reset */
+ if (!chip->read_byte || chip->read_byte == nand_read_byte)
chip->read_byte = busw ? nand_read_byte16 : nand_read_byte;
if (!chip->read_word)
chip->read_word = nand_read_word;
@@ -2801,9 +2803,9 @@ static void nand_set_defaults(struct nan
chip->block_bad = nand_block_bad;
if (!chip->block_markbad)
chip->block_markbad = nand_default_block_markbad;
- if (!chip->write_buf)
+ if (!chip->write_buf || chip->write_buf == nand_write_buf)
chip->write_buf = busw ? nand_write_buf16 : nand_write_buf;
- if (!chip->read_buf)
+ if (!chip->read_buf || chip->read_buf == nand_read_buf)
chip->read_buf = busw ? nand_read_buf16 : nand_read_buf;
if (!chip->scan_bbt)
chip->scan_bbt = nand_default_bbt;
Patches currently in stable-queue which might be from computersforpeace@xxxxxxxxx are
queue-3.11/mtd-nand-fix-nand_buswidth_auto-for-x16-devices.patch
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