[PATCH] mmc: core: fix dead loop of mmc_retune

Adrian Hunter
2015-09-30T12:01:31Z

On 30/09/15 12:37, Chaotian Jing wrote:
> When get a CRC error, start the mmc_retune, it will issue CMD19/CMD21
> to do tune, assume there were 10 clock phase need to try, phase 0 to
> phase 6 is ok, phase 7 to phase 9 is NG, we try it from 0 to 9, so
> the last CMD19/CMD21 will get CRC error, host->need_retune was set and
> cause mmc_retune was called, then dead loop of mmc_retune
>
> Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com>

Wasn't my idea to have this CRC checking in the core ;-) and sdhci
doesn't put it's tuning commands through a mmc request so it doesn't
see this issue.

But definitely the CRC logic is not meant for the tuning commands, so

Acked-by: Adrian Hunter <adrian.hunter@intel.com>

> ---
> drivers/mmc/core/core.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 0520064..a3eb20b 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -134,9 +134,11 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
> int err = cmd->error;
>
> /* Flag re-tuning needed on CRC errors */
> - if (err == -EILSEQ || (mrq->sbc && mrq->sbc->error == -EILSEQ) ||
> + if ((cmd->opcode != MMC_SEND_TUNING_BLOCK &&
> + cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200) &&
> + (err == -EILSEQ || (mrq->sbc && mrq->sbc->error == -EILSEQ) ||
> (mrq->data && mrq->data->error == -EILSEQ) ||
> - (mrq->stop && mrq->stop->error == -EILSEQ))
> + (mrq->stop && mrq->stop->error == -EILSEQ)))
> mmc_retune_needed(host);
>
> if (err && cmd->retries && mmc_host_is_spi(host)) {
>