On Tue, Aug 07, 2018 at 04:59:59PM +0300, Aapo Vienamo wrote:
> Implement HS400 enhanced strobe.

Can you provide a little more information about what the impact is of
this? Does this increase throughput? How much?

> 
> Signed-off-by: Aapo Vienamo <avien...@nvidia.com>
> ---
>  drivers/mmc/host/sdhci-tegra.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
> index 426f7ea..d81143b 100644
> --- a/drivers/mmc/host/sdhci-tegra.c
> +++ b/drivers/mmc/host/sdhci-tegra.c
> @@ -43,6 +43,9 @@
>  #define SDHCI_CLOCK_CTRL_PADPIPE_CLKEN_OVERRIDE              BIT(3)
>  #define SDHCI_CLOCK_CTRL_SPI_MODE_CLKEN_OVERRIDE     BIT(2)
>  
> +#define SDHCI_TEGRA_VENDOR_SYS_SW_CTRL                       0x104
> +#define SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE              BIT(31)
> +
>  #define SDHCI_TEGRA_VENDOR_CAP_OVERRIDES             0x10c
>  #define SDHCI_TEGRA_CAP_OVERRIDES_DQS_TRIM_MASK              0x00003f00
>  #define SDHCI_TEGRA_CAP_OVERRIDES_DQS_TRIM_SHIFT     8
> @@ -271,6 +274,22 @@ static void tegra_sdhci_set_tap(struct sdhci_host *host, 
> unsigned int tap)
>       }
>  }
>  
> +static void tegra_sdhci_hs400_enhanced_strobe(struct mmc_host *mmc,
> +                                           struct mmc_ios *ios)
> +{
> +     struct sdhci_host *host = mmc_priv(mmc);
> +     u32 reg;
> +
> +     reg = sdhci_readl(host, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL);
> +     pr_err("enhanced strobe: %d\n", ios->enhanced_strobe);

Left-over debug error?

> +     if (ios->enhanced_strobe)
> +             reg |= SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE;
> +     else
> +             reg &= ~SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE;
> +     sdhci_writel(host, reg, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL);

You might want to add blank lines around the if ... else ... block for
readability.

Thierry

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