On 16/11/16 12:51, Ulf Hansson wrote:
> In cases when the mmc host doesn't support HW busy detection, polling for
> busy by using CMD13 is beneficial. The reasons have already been explained
> in earlier change logs.
>
> Moreover, when polling with CMD13 during bus timing changes, we should
> retry instead of fail when we get CRC errors.
>
> Switching to HS400ES includes several steps, where each step changes the
> bus speed timing. Let's improve the behaviour during these sequences, by
> allowing CMD13 polling for each of the step. Let's also make sure the CMD13
> polling becomes retried, while receiving a CRC error.
>
> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> ---
> drivers/mmc/core/mmc.c | 35 +++++++++++------------------------
> 1 file changed, 11 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 24b9e72..b6f0035 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1227,31 +1227,24 @@ static int mmc_select_hs400es(struct mmc_card *card)
> goto out_err;
>
> /* Switch card to HS mode */
> - err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> - EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS,
> - card->ext_csd.generic_cmd6_time, 0,
> - true, false, true);
> + err = mmc_select_hs(card);
> if (err) {
> pr_err("%s: switch to hs for hs400es failed, err:%d\n",
> mmc_hostname(host), err);
> goto out_err;
> }
>
> - mmc_set_timing(host, MMC_TIMING_MMC_HS);
> - err = mmc_switch_status(card);
> - if (err)
> - goto out_err;
> -
> mmc_set_clock(host, card->ext_csd.hs_max_dtr);
>
> - /* Switch card to DDR with strobe bit */
> + /* Switch card to HS DDR with strobe bit */
> val = EXT_CSD_DDR_BUS_WIDTH_8 | EXT_CSD_BUS_WIDTH_STROBE;
> - err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> - EXT_CSD_BUS_WIDTH,
> - val,
> - card->ext_csd.generic_cmd6_time);
> + err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> + EXT_CSD_BUS_WIDTH, val,
> + card->ext_csd.generic_cmd6_time,
> + MMC_TIMING_MMC_DDR52,
> + true, true, true);
> if (err) {
> - pr_err("%s: switch to bus width for hs400es failed, err:%d\n",
> + pr_err("%s: switch to hs ddr for hs400es failed, err:%d\n",
> mmc_hostname(host), err);
> goto out_err;
> }
> @@ -1261,26 +1254,20 @@ static int mmc_select_hs400es(struct mmc_card *card)
> card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
> err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> EXT_CSD_HS_TIMING, val,
> - card->ext_csd.generic_cmd6_time, 0,
> - true, false, true);
> + card->ext_csd.generic_cmd6_time,
> + MMC_TIMING_MMC_HS400,
> + true, true, true);
This could be a problem because the CMD13 is being sent to a card in HS400
enhanced strobe mode but we haven't enabled enhanced strobe on the host
controller yet. Previously mmc_switch_status(card) was below
host->ops->hs400_enhanced_strobe().
> if (err) {
> pr_err("%s: switch to hs400es failed, err:%d\n",
> mmc_hostname(host), err);
> goto out_err;
> }
>
> - /* Set host controller to HS400 timing and frequency */
> - mmc_set_timing(host, MMC_TIMING_MMC_HS400);
> -
> /* Controller enable enhanced strobe function */
> host->ios.enhanced_strobe = true;
> if (host->ops->hs400_enhanced_strobe)
> host->ops->hs400_enhanced_strobe(host, &host->ios);
>
> - err = mmc_switch_status(card);
> - if (err)
> - goto out_err;
> -
> return 0;
>
> out_err:
>
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