On 20/12/18 1:38 PM, BOUGH CHEN wrote:
> DDR50 tuning is optinally defined in sd 3.0 spec. For example,
> i.MX uSDHC internally already uses a fixed optimized timing for
> DDR50, normally does not require tuning for DDR50 mode.
>
> So this patch make DDR50 tuning optionally and platform can claim
> SDHCI_DDR50_NEEDS_TUNING to support if it wants tuning.
It is optional to call sdhci_execute_tuning(). Consider
xenon_execute_tuning() for example.
>
> Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
> ---
> drivers/mmc/host/sdhci.c | 6 +++++-
> drivers/mmc/host/sdhci.h | 1 +
> 2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 67e43ec..144418e 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2429,9 +2429,13 @@ int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
> break;
>
> case MMC_TIMING_UHS_SDR104:
> - case MMC_TIMING_UHS_DDR50:
> break;
>
> + case MMC_TIMING_UHS_DDR50:
> + if (host->flags & SDHCI_DDR50_NEEDS_TUNING)
> + break;
> + /* FALLTHROUGH */
> +
> case MMC_TIMING_UHS_SDR50:
> if (host->flags & SDHCI_SDR50_NEEDS_TUNING)
> break;
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 6cc9a3c..58b363b 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -506,6 +506,7 @@ struct sdhci_host {
> #define SDHCI_REQ_USE_DMA (1<<2) /* Use DMA for this req. */
> #define SDHCI_DEVICE_DEAD (1<<3) /* Device unresponsive */
> #define SDHCI_SDR50_NEEDS_TUNING (1<<4) /* SDR50 needs tuning */
> +#define SDHCI_DDR50_NEEDS_TUNING (1<<5) /* DDR50 needs tuning */
> #define SDHCI_AUTO_CMD12 (1<<6) /* Auto CMD12 support */
> #define SDHCI_AUTO_CMD23 (1<<7) /* Auto CMD23 support */
> #define SDHCI_PV_ENABLED (1<<8) /* Preset value enabled */
>
