On Wed, 19 Feb 2020 at 22:07, Jean-Francois Dagenais
<jeff.dagenais@xxxxxxxxx> wrote:
>
> Regardless of the broken-cd quirk, when it silently doesn't stick,
> no clock is applied to the bus lines, yet the code continues to
> try to make CMDs and times out after 10 seconds for each. This
> process can take up to a minute as mmc_rescan_try_freq tries the
> different commands to discover the card.
>
> Short of changing sdhci_enable_clk's signature chain in all
> dependent drivers, at least provide a hint that this might be the
> problem. This will save tons of time for system integrators.
>
> Signed-off-by: Jean-Francois Dagenais <jeff.dagenais@xxxxxxxxx>
The change looks reasonable to me. However I would like to get an ack
by Adrian before applying, as I may not have thought of all the
consequences this change may have.
Kind regards
Uffe
> ---
> Changes in v2:
> * removed redundant wmb()
> ---
> drivers/mmc/host/sdhci.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 63db84481dff..42a02d034fda 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1894,6 +1894,20 @@ void sdhci_enable_clk(struct sdhci_host *host, u16 clk)
>
> clk |= SDHCI_CLOCK_CARD_EN;
> sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
> +
> + clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
> + if (clk & SDHCI_CLOCK_CARD_EN)
> + return;
> +
> + /* The controller will clear this bit if card absent condition is
> + * detected. If card is indeed present, check platform configuration for
> + * how CD is reported to the SDHCI host controller. There may be an
> + * "assume present" mechanism in the platform registers, or your pin mux
> + * may be incorrect.
> + */
> + pr_err("%s: SDHCI_CLOCK_CARD_EN bit did not stick. Card absent?\n",
> + mmc_hostname(host->mmc));
> + sdhci_dumpregs(host);
> }
> EXPORT_SYMBOL_GPL(sdhci_enable_clk);
>
> --
> 2.25.0
>
