Hi Tokunori,
ikegami.t@gmail.com wrote on Wed, 16 Mar 2022 01:56:07 +0900:
As pointed out by this bug report [1], the buffered write is now broken on
, buffered writes are now broken
S29GL064N. The reason is that changed the buffered write to use chip_good instead of chip_ready.
"This issue comes from a rework which switched from using chip_good() to chip_ready(), because <explain the difference here>."
[please note I am just trying to understand what the root cause is, please rephrase if I'm wrong].
One way to solve the issue is to revert the change partially to use chip_ready for S29GL064N since the way of least surprise.
s/since the way of least surprise//
[1] https://lore.kernel.org/r/b687c259-6413-26c9-d4c9-b3afa69ea124@pengutronix.d...
Fixes: dfeae1073583("mtd: cfi_cmdset_0002: Change write buffer to check correct value") Signed-off-by: Tokunori Ikegami ikegami.t@gmail.com Tested-by: Ahmad Fatoum a.fatoum@pengutronix.de Cc: Miquel Raynal miquel.raynal@bootlin.com Cc: Richard Weinberger richard@nod.at Cc: Vignesh Raghavendra vigneshr@ti.com Cc: linux-mtd@lists.infradead.org
I think you can get rid of all the above Cc: tags and just copy all 3 of us + the mailing list when sending your v4.
Cc: stable@vger.kernel.org
Please also include a Fixes/stable tag in the patch before (2/3) to explain that both patches are required in order to fix the issue and the current patch alone won't apply.
You should mention that with a nice comment below the three dashes ("---") in patch 2/3 as well.
drivers/mtd/chips/cfi_cmdset_0002.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c index 8f3f0309dc03..fa11db066c99 100644 --- a/drivers/mtd/chips/cfi_cmdset_0002.c +++ b/drivers/mtd/chips/cfi_cmdset_0002.c @@ -867,10 +867,20 @@ static int __xipram chip_good(struct map_info *map, struct flchip *chip, return chip_check(map, chip, addr, &expected); } +static bool __xipram cfi_use_chip_ready_for_write(struct map_info *map) +{
- struct cfi_private *cfi = map->fldrv_priv;
- return cfi->mfr == CFI_MFR_AMD && cfi->id == S29GL064N_MN12;
+}
static int __xipram chip_good_for_write(struct map_info *map, struct flchip *chip, unsigned long addr, map_word expected) {
- if (cfi_use_chip_ready_for_write(map))
return chip_ready(map, chip, addr);- return chip_good(map, chip, addr, expected);
}
This is much more understandable.
Vignesh, perhaps it would be better to provide a way for manufacturers to overload certain callbacks instead of applying quirks like this in the code. But that will come in a second time of course.
Thanks, Miquèl