On 21/11/13 17:07, Vladimir Zapolskiy wrote:
> JEDEC specification defines quite high erase timeout value for 300ms
> multiplied by erase group number, and SD Host Controller specification
> data line timeout may be much less, e.g. 2^13 / 52MHz ~ 160us.
>
>>From block layer and MMC perfromance perspective it is desirable that
> millions of erase groups are discarded at once, so there is no much
> sense to limit maximum erase timeout by data line timeout, if a
> controller handles correctly erase operation without indication of
> data line timeout.
Would you explain that some more. Do you mean that:
a) it does not have a timeout
b) it has a timeout which is less than the timeout specified by the
standard but the operation nevertheless completes
>
> Potentially the change may break some of the SDHCs on discard of mmc,
> and for backward compatibility a new quirk is introduced, which is NOT
> set by default.
It sounds to me that what you want to do is not standard so the quirk should
be the other way around.
>
> Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@xxxxxxxxxx>
> Reported-by: Ed Sutter <ed.sutter@xxxxxxxxxxxxxxxxxx>
> Cc: Chris Ball <cjb@xxxxxxxxxx>
> Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
> drivers/mmc/host/sdhci.c | 5 ++++-
> include/linux/mmc/sdhci.h | 1 +
> 2 files changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index bd8a098..b1fdddb 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2930,7 +2930,10 @@ int sdhci_add_host(struct sdhci_host *host)
> if (host->quirks & SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK)
> host->timeout_clk = mmc->f_max / 1000;
>
> - mmc->max_discard_to = (1 << 27) / host->timeout_clk;
> + if (host->quirks2 & SDHCI_QUIRK2_DATA_TIMEOUT_ON_DISCARD)
> + mmc->max_discard_to = (1 << 27) / host->timeout_clk;
> + else
> + mmc->max_discard_to = 0;
>
> mmc->caps |= MMC_CAP_SDIO_IRQ | MMC_CAP_ERASE | MMC_CAP_CMD23;
>
> diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
> index 3e781b8..e7f6bd2 100644
> --- a/include/linux/mmc/sdhci.h
> +++ b/include/linux/mmc/sdhci.h
> @@ -98,6 +98,7 @@ struct sdhci_host {
> #define SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON (1<<4)
> /* Controller has a non-standard host control register */
> #define SDHCI_QUIRK2_BROKEN_HOST_CONTROL (1<<5)
> +#define SDHCI_QUIRK2_DATA_TIMEOUT_ON_DISCARD (1<<6)
>
> int irq; /* Device IRQ */
> void __iomem *ioaddr; /* Mapped address */
>
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