[U-Boot] [PATCH 22/22] mmc: Retry some MMC cmds on failure

[Simon Glass]

On 12 May 2017 at 12:16, Jean-Jacques Hiblot <jjhiblot at ti.com> wrote:
> From: Vignesh R <vigneshr at ti.com>
>
> With certain SD cards like Kingston 8GB/16GB UHS card, it is seen that
> MMC_CMD_ALL_SEND_CID cmd fails on first attempt, but succeeds
> subsequently. Therefore, retry MMC_CMD_ALL_SEND_CID cmd at least thrice
> as done in Linux kernel.
> Similarly, it is seen that MMC_CMD_SET_BLOCKLEN may fail on first
> attempt, therefore retry this cmd five times as done in kernel.
>
> Signed-off-by: Vignesh R <vigneshr at ti.com>
> Signed-off-by: Kishon Vijay Abraham I <kishon at ti.com>
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot at ti.com>
> ---
>  drivers/mmc/mmc.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
>

So sad to see this sort of thing.

Can we enable this via a quirk and a Kconfig? Could default to on, but
I'm not sure we want this code in regardless.

Reviewed-by: Simon Glass <sjg at chromium.org>


> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
> index c7dda64..49edf52 100644
> --- a/drivers/mmc/mmc.c
> +++ b/drivers/mmc/mmc.c
> @@ -275,6 +275,8 @@ int mmc_send_status(struct mmc *mmc, int timeout)
>  int mmc_set_blocklen(struct mmc *mmc, int len)
>  {
>         struct mmc_cmd cmd;
> +       int retries = 5;
> +       int err;
>
>         if (mmc->ddr_mode)
>                 return 0;
> @@ -282,8 +284,13 @@ int mmc_set_blocklen(struct mmc *mmc, int len)
>         cmd.cmdidx = MMC_CMD_SET_BLOCKLEN;
>         cmd.resp_type = MMC_RSP_R1;
>         cmd.cmdarg = len;
> +       do {
> +               err = mmc_send_cmd(mmc, &cmd, NULL);
> +               if (!err)
> +                       break;
> +       } while (retries--);
>
> -       return mmc_send_cmd(mmc, &cmd, NULL);
> +       return err;
>  }
>
>  static int mmc_read_blocks(struct mmc *mmc, void *dst, lbaint_t start,
> @@ -1867,6 +1874,7 @@ static int mmc_startup(struct mmc *mmc)
>         u64 cmult, csize;
>         struct mmc_cmd cmd;
>         struct blk_desc *bdesc;
> +       int retries = 3;
>
>  #ifdef CONFIG_MMC_SPI_CRC_ON
>         if (mmc_host_is_spi(mmc)) { /* enable CRC check for spi */
> @@ -1874,7 +1882,6 @@ static int mmc_startup(struct mmc *mmc)
>                 cmd.resp_type = MMC_RSP_R1;
>                 cmd.cmdarg = 1;
>                 err = mmc_send_cmd(mmc, &cmd, NULL);
> -
>                 if (err)
>                         return err;
>         }
> @@ -1886,7 +1893,9 @@ static int mmc_startup(struct mmc *mmc)
>         cmd.resp_type = MMC_RSP_R2;
>         cmd.cmdarg = 0;
>
> -       err = mmc_send_cmd(mmc, &cmd, NULL);
> +       do {
> +               err = mmc_send_cmd(mmc, &cmd, NULL);
> +       } while (err && retries-- > 0);
>
>         if (err)
>                 return err;
> --
> 1.9.1
>