On 04/08/17 05:08, Shawn Lin wrote:
> Per the SD physical layer simplified specification V4.10,
> section 4.6.2, CSD version 1.0 SD card should use taac, nsac
> and r2w_factor for calculating the data access time. But the
> taac and nsac for SDHC(CSD version 2.0) are always fixed and
> the software should use the recommended value for timeout. When
> parsing the CSD, we sanely set them to zero for SDHC(CSD version
> 2.0), all the calculation for timeout_ns and timeout_clk is zero
> as well. So what we actually want to limit here is either SDHC
> case or unreasonable timeout reported by the cards. In principle
> we should at least be able to remove the bogus check for the
> mmc_card_blockaddr.
>
> Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
>
> ---
>
> Changes in v2:
> - rephrase the changelog and only remove mmc_card_blockaddr.
>
> drivers/mmc/core/core.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 6177eb0..edc2e75 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -761,15 +761,11 @@ void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card)
> limit_us = 100000;
>
> /*
> - * SDHC cards always use these fixed values.
> + * Assign limit value if invalid. Note that for the SDHC case,
> + * we set taac and nasc to zero when parsing CSD, so it's safe
> + * to fall through here.
> */
> - if (timeout_us > limit_us || mmc_card_blockaddr(card)) {
> - data->timeout_ns = limit_us * 1000;
> - data->timeout_clks = 0;
> - }
> -
> - /* assign limit value if invalid */
> - if (timeout_us == 0)
> + if (timeout_us == 0 || timeout_us > limit_us)
> data->timeout_ns = limit_us * 1000;
Shouldn't we still be ensuring 'data->timeout_clks = 0' for the 'timeout_us
> limit_us' case
> }
>
>
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