In OpenWrt Project the flash write error caused on some products. Also the issue can be fixed by using chip_good() instead of chip_ready(). The chip_ready() just checks the value from flash memory twice. And the chip_good() checks the value with the expected value. Probably the issue can be fixed as checked correctly by the chip_good(). So change to use chip_good() instead of chip_ready().
Signed-off-by: Tokunori Ikegami ikegami@allied-telesis.co.jp Signed-off-by: Hauke Mehrtens hauke@hauke-m.de Signed-off-by: Koen Vandeputte koen.vandeputte@ncentric.com Signed-off-by: Fabio Bettoni fbettoni@gmail.com Co-Developed-by: Hauke Mehrtens hauke@hauke-m.de Co-Developed-by: Koen Vandeputte koen.vandeputte@ncentric.com Co-Developed-by: Fabio Bettoni fbettoni@gmail.com Reported-by: Fabio Bettoni fbettoni@gmail.com Cc: Chris Packham chris.packham@alliedtelesis.co.nz Cc: Joakim Tjernlund Joakim.Tjernlund@infinera.com Cc: Boris Brezillon boris.brezillon@free-electrons.com Cc: linux-mtd@lists.infradead.org Cc: stable@vger.kernel.org --- Changes since v2: - Just update the commit message for the comment.
Changes since v1: - Just update the commit message.
Background: This is required for OpenWrt Project to result the flash write issue as below patche. https://git.openwrt.org/?p=openwrt/openwrt.git;a=commitdiff;h=ddc11c3932c7b7b7df7d5fbd48f207e77619eaa7
Also the original patch in OpenWRT is below. https://github.com/openwrt/openwrt/blob/v18.06.0/target/linux/ar71xx/patches-4.9/403-mtd_fix_cfi_cmdset_0002_status_check.patch
The reason to use chip_good() is that just actually fix the issue. And also in the past I had fixed the erase function also as same way by the patch below. https://patchwork.ozlabs.org/patch/922656/ Note: The reason for the patch for erase is same.
In my understanding the chip_ready() is just checked the value twice from flash. So I think that sometimes incorrect value is read twice and it is depended on the flash device behavior but not sure..
So change to use chip_good() instead of chip_ready().
drivers/mtd/chips/cfi_cmdset_0002.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c index 72428b6bfc47..251c9e1675bd 100644 --- a/drivers/mtd/chips/cfi_cmdset_0002.c +++ b/drivers/mtd/chips/cfi_cmdset_0002.c @@ -1627,31 +1627,37 @@ static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip, continue; }
- if (time_after(jiffies, timeo) && !chip_ready(map, adr)){ + if (chip_good(map, adr, datum)) + break; + + if (time_after(jiffies, timeo)){ xip_enable(map, chip, adr); printk(KERN_WARNING "MTD %s(): software timeout\n", __func__); xip_disable(map, chip, adr); + ret = -EIO; break; }
- if (chip_ready(map, adr)) - break; - /* Latency issues. Drop the lock, wait a while and retry */ UDELAY(map, chip, adr, 1); } + /* Did we succeed? */ - if (!chip_good(map, adr, datum)) { + if (ret) { /* reset on all failures. */ map_write(map, CMD(0xF0), chip->start); /* FIXME - should have reset delay before continuing */
- if (++retry_cnt <= MAX_RETRIES) + if (++retry_cnt <= MAX_RETRIES) { + ret = 0; goto retry; + }
ret = -EIO; } + xip_enable(map, chip, adr); + op_done: if (mode == FL_OTP_WRITE) otp_exit(map, chip, adr, map_bankwidth(map));