From: Joakim.Tjernlund@infinera.com (Joakim Tjernlund)
To: linux-mtd@lists.infradead.org
Subject: [PATCH] mtd: cfi: Fixed endless loop problem in CFI when value was written but corrupted.
Date: Wed, 16 Jan 2019 08:33:13 +0000 [thread overview]
Message-ID: <acd7f2257808f78aa76840e6789c7f65c08986ef.camel@infinera.com> (raw)
In-Reply-To: <20190116003211.GA57460@dev-dsk-psobon-2c-1dd9f399.us-west-2.amazon.com>
On Wed, 2019-01-16 at 00:32 +0000, Przemyslaw Sobon wrote:
>
>
> There was an endless loop in CFI Flash driver when a value was written
> incorrectly. In such case chip_ready returns true but chip_good returns
> false and we never get out of the loop.
>
> The solution was to break the loop in 2 cases, either device is ready or
> device is not ready and timeout elapsed. The correctness of the write is
> checked after the loop ended. That way we ensure the loop always ends.
>
> Signed-off-by: Przemyslaw Sobon <psobon@amazon.com>
hmm, current code was introduced by Tokunori Ikegami <ikegami@allied-telesis.co.jp> to address another problem he had.
See
mtd: cfi_cmdset_0002: Change write buffer to check correct value
and
mtd: cfi_cmdset_0002: Change erase functions to check chip good only
I wonder if you need to wrap an extra loop with retries around chip_good to adress the problem Tokunori had.
Tokunori, what do you think ?
Jocke
> ---
> drivers/mtd/chips/cfi_cmdset_0002.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
> index 72428b6bfc47..6cc31d2057e9 100644
> --- a/drivers/mtd/chips/cfi_cmdset_0002.c
> +++ b/drivers/mtd/chips/cfi_cmdset_0002.c
> @@ -1879,15 +1879,18 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
> if (time_after(jiffies, timeo) && !chip_ready(map, adr))
> break;
>
> - if (chip_good(map, adr, datum)) {
> - xip_enable(map, chip, adr);
> - goto op_done;
> - }
> + if (chip_ready(map, adr))
> + break;
>
> /* Latency issues. Drop the lock, wait a while and retry */
> UDELAY(map, chip, adr, 1);
> }
>
> + if (chip_good(map, adr, datum)) {
> + xip_enable(map, chip, adr);
> + goto op_done;
> + }
> +
> /*
> * Recovery from write-buffer programming failures requires
> * the write-to-buffer-reset sequence. Since the last part
> --
> 2.16.5
>
>
> ______________________________________________________
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next prev parent reply other threads:[~2019-01-16 8:33 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-16 0:32 [PATCH] mtd: cfi: Fixed endless loop problem in CFI when value was written but corrupted Przemyslaw Sobon
2019-01-16 8:33 ` Joakim Tjernlund [this message]
2019-01-16 8:50 ` Joakim Tjernlund
2019-01-16 8:54 ` Sobon, Przemyslaw
2019-02-07 23:58 Przemyslaw Sobon
2019-02-08 15:01 ` Tokunori Ikegami
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