Re: [PATCH v2 01/10] mtd: cfi_cmdset_0002: Change do_write_oneword() to use chip_good()

On 20/10/18 5:55 AM, Tokunori Ikegami wrote:

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

So change to use chip_good() instead of chip_ready().

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().

I think much of this is commentary for readers of the mailing list not something that should be in the final commit (i.e. it should be after the '---'). The commit message should really reflect what the problem was and how this change fixes it.

I think you've got a better handle on what chip_good() does than I do so I won't attempt to provide a commit message here.

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 v1:

• Just update the commit message.

  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));