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SubjectRe: [PATCH 3/8] mmc: tegra: Implement HS400 enhanced strobe
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 <avienamo@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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