mmc: tmio: fix SCC error handling to avoid false positive CRC error
diff mbox series

Message ID 20190515182346.5292-1-wsa+renesas@sang-engineering.com
State Under Review
Delegated to: Kieran Bingham
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Series
  • mmc: tmio: fix SCC error handling to avoid false positive CRC error
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Commit Message

Wolfram Sang May 15, 2019, 6:23 p.m. UTC
From: Takeshi Saito <takeshi.saito.xv@renesas.com>

If an SCC error occurs during a read/write command execution, a false
positive CRC error message is output.

mmcblk0: response CRC error sending r/w cmd command, card status 0x900

check_scc_error() checks SCC_RVSREQ.RVSERR bit. RVSERR detects a
correction error in the next (up or down) delay tap position. However,
since the command is successful, only retuning needs to be executed.
This has been confirmed by HW engineers.

Thus, on SCC error, set retuning flag instead of setting an error code.

Fixes: b85fb0a1c8ae ("mmc: tmio: Fix SCC error detection")
Signed-off-by: Takeshi Saito <takeshi.saito.xv@renesas.com>
[wsa: updated comment and commit message, removed some braces]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---

This patch was suggested by the BSP team because they were seeing CRC errors
with a hardware I don't have access to. I tested this with my R-Car H3-ES2.0
and M3-N (both Salvator-XS), and things were still running fine. But I suggest
to wait for a final ack from Shimoda-san or someone from the BSP team.


 drivers/mmc/host/tmio_mmc_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Simon Horman May 16, 2019, 11:22 a.m. UTC | #1
On Wed, May 15, 2019 at 08:23:46PM +0200, Wolfram Sang wrote:
> From: Takeshi Saito <takeshi.saito.xv@renesas.com>
> 
> If an SCC error occurs during a read/write command execution, a false
> positive CRC error message is output.
> 
> mmcblk0: response CRC error sending r/w cmd command, card status 0x900
> 
> check_scc_error() checks SCC_RVSREQ.RVSERR bit. RVSERR detects a
> correction error in the next (up or down) delay tap position. However,
> since the command is successful, only retuning needs to be executed.
> This has been confirmed by HW engineers.
> 
> Thus, on SCC error, set retuning flag instead of setting an error code.
> 
> Fixes: b85fb0a1c8ae ("mmc: tmio: Fix SCC error detection")
> Signed-off-by: Takeshi Saito <takeshi.saito.xv@renesas.com>
> [wsa: updated comment and commit message, removed some braces]
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Yoshihiro Shimoda May 21, 2019, 7:11 a.m. UTC | #2
Hi Wolfram-san,

> From: Wolfram Sang, Sent: Thursday, May 16, 2019 3:24 AM
> 
> From: Takeshi Saito <takeshi.saito.xv@renesas.com>
> 
> If an SCC error occurs during a read/write command execution, a false
> positive CRC error message is output.
> 
> mmcblk0: response CRC error sending r/w cmd command, card status 0x900
> 
> check_scc_error() checks SCC_RVSREQ.RVSERR bit. RVSERR detects a
> correction error in the next (up or down) delay tap position. However,
> since the command is successful, only retuning needs to be executed.
> This has been confirmed by HW engineers.
> 
> Thus, on SCC error, set retuning flag instead of setting an error code.
> 
> Fixes: b85fb0a1c8ae ("mmc: tmio: Fix SCC error detection")
> Signed-off-by: Takeshi Saito <takeshi.saito.xv@renesas.com>
> [wsa: updated comment and commit message, removed some braces]
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
> 
> This patch was suggested by the BSP team because they were seeing CRC errors
> with a hardware I don't have access to. I tested this with my R-Car H3-ES2.0
> and M3-N (both Salvator-XS), and things were still running fine. But I suggest
> to wait for a final ack from Shimoda-san or someone from the BSP team.

Thank you for the patch!

Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

Best regards,
Yoshihiro Shimoda
Ulf Hansson May 28, 2019, 8:52 a.m. UTC | #3
On Wed, 15 May 2019 at 20:24, Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
>
> From: Takeshi Saito <takeshi.saito.xv@renesas.com>
>
> If an SCC error occurs during a read/write command execution, a false
> positive CRC error message is output.
>
> mmcblk0: response CRC error sending r/w cmd command, card status 0x900
>
> check_scc_error() checks SCC_RVSREQ.RVSERR bit. RVSERR detects a
> correction error in the next (up or down) delay tap position. However,
> since the command is successful, only retuning needs to be executed.
> This has been confirmed by HW engineers.
>
> Thus, on SCC error, set retuning flag instead of setting an error code.
>
> Fixes: b85fb0a1c8ae ("mmc: tmio: Fix SCC error detection")
> Signed-off-by: Takeshi Saito <takeshi.saito.xv@renesas.com>
> [wsa: updated comment and commit message, removed some braces]
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Applied for fixes and by adding a stable tag, thanks!

Kind regards
Uffe


> ---
>
> This patch was suggested by the BSP team because they were seeing CRC errors
> with a hardware I don't have access to. I tested this with my R-Car H3-ES2.0
> and M3-N (both Salvator-XS), and things were still running fine. But I suggest
> to wait for a final ack from Shimoda-san or someone from the BSP team.
>
>
>  drivers/mmc/host/tmio_mmc_core.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c
> index 595949f1f001..78cc2a928efe 100644
> --- a/drivers/mmc/host/tmio_mmc_core.c
> +++ b/drivers/mmc/host/tmio_mmc_core.c
> @@ -842,8 +842,9 @@ static void tmio_mmc_finish_request(struct tmio_mmc_host *host)
>         if (mrq->cmd->error || (mrq->data && mrq->data->error))
>                 tmio_mmc_abort_dma(host);
>
> +       /* SCC error means retune, but executed command was still successful */
>         if (host->check_scc_error && host->check_scc_error(host))
> -               mrq->cmd->error = -EILSEQ;
> +               mmc_retune_needed(host->mmc);
>
>         /* If SET_BLOCK_COUNT, continue with main command */
>         if (host->mrq && !mrq->cmd->error) {
> --
> 2.11.0
>

Patch
diff mbox series

diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c
index 595949f1f001..78cc2a928efe 100644
--- a/drivers/mmc/host/tmio_mmc_core.c
+++ b/drivers/mmc/host/tmio_mmc_core.c
@@ -842,8 +842,9 @@  static void tmio_mmc_finish_request(struct tmio_mmc_host *host)
 	if (mrq->cmd->error || (mrq->data && mrq->data->error))
 		tmio_mmc_abort_dma(host);
 
+	/* SCC error means retune, but executed command was still successful */
 	if (host->check_scc_error && host->check_scc_error(host))
-		mrq->cmd->error = -EILSEQ;
+		mmc_retune_needed(host->mmc);
 
 	/* If SET_BLOCK_COUNT, continue with main command */
 	if (host->mrq && !mrq->cmd->error) {