On Wed, 15 Jan 2020 at 10:54, Michał Mirosław <mirq-linux@xxxxxxxxxxxx> wrote:
>
> For SDHCIv3+ with programmable clock mode, minimal clock frequency is
> still base clock / max(divider). Minimal programmable clock frequency is
> always greater than minimal divided clock frequency. Without this patch,
> SDHCI uses out-of-spec initial frequency when multiplier is big enough:
>
> mmc1: mmc_rescan_try_freq: trying to init card at 468750 Hz
> [for 480 MHz source clock divided by 1024]
>
> The code in sdhci_calc_clk() already chooses a correct SDCLK clock mode.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: c3ed3877625f ("mmc: sdhci: add support for programmable clock mode")
> Signed-off-by: Michał Mirosław <mirq-linux@xxxxxxxxxxxx>
Applied for fixes, thanks!
Kind regards
Uffe
> ---
> v3: commitmsg/comment rewording
> v2: extend commitmsg and add comment
> ---
> drivers/mmc/host/sdhci.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 96609c961465..24fb6d710de6 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -3903,11 +3903,13 @@ int sdhci_setup_host(struct sdhci_host *host)
> if (host->ops->get_min_clock)
> mmc->f_min = host->ops->get_min_clock(host);
> else if (host->version >= SDHCI_SPEC_300) {
> - if (host->clk_mul) {
> - mmc->f_min = (host->max_clk * host->clk_mul) / 1024;
> + if (host->clk_mul)
> max_clk = host->max_clk * host->clk_mul;
> - } else
> - mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_300;
> + /*
> + * Divided Clock Mode minimum clock rate is always less than
> + * Programmable Clock Mode minimum clock rate.
> + */
> + mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_300;
> } else
> mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_200;
>
> --
> 2.20.1
>
