On Wed, Jul 29, 2015 at 05:03:56PM +0800, Haibo Chen wrote:
> i.MX7D support eMMC HS400 mode, this mode can run in 8 bit,200MHZ
> DDR mode. So the I/O speed improve a lot compare to SD3.0
>
> The default burst length is 8, if we don't change this value, in
> HS400 mode, when we do eMMC read operation, we can find that the
> clock signal will stop for a period of time. This means the speed
> of data moving on AHB bus is slower than I/O speed. So we should
> improve the speed of data moving on AHB bus.
>
> For imx7d usdhc, this patch set the burst length as 16, and set
> watermark level as 64. The test result is the clock signal has
> no stop during the eMMC HS400 operation. For other imx usdhc, remain
> the default value: burst length as 8, watermark level as 16.
>
> Signed-off-by: Haibo Chen <haibo.chen@xxxxxxxxxxxxx>
> ---
> drivers/mmc/host/sdhci-esdhc-imx.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index 158f93b..37d0095 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -239,6 +239,11 @@ static inline int is_imx6q_usdhc(struct pltfm_imx_data *data)
> return data->socdata == &usdhc_imx6q_data;
> }
>
> +static inline int is_imx7d_usdhc(struct pltfm_imx_data *data)
> +{
> + return data->socdata == &usdhc_imx7d_data;
> +}
Can we using flag to check instead of adding more is_imx_usdhc()?
> +
> static inline int esdhc_is_usdhc(struct pltfm_imx_data *data)
> {
> return !!(data->socdata->flags & ESDHC_FLAG_USDHC);
> @@ -1145,7 +1150,11 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev)
> * to something insane. Change it back here.
> */
> if (esdhc_is_usdhc(imx_data)) {
> - writel(0x08100810, host->ioaddr + ESDHC_WTMK_LVL);
> + if (is_imx7d_usdhc(imx_data))
> + writel(0x10401040, host->ioaddr + ESDHC_WTMK_LVL);
> + else
> + writel(0x08100810, host->ioaddr + ESDHC_WTMK_LVL);
> +
> host->quirks2 |= SDHCI_QUIRK2_PRESET_VALUE_BROKEN;
> host->mmc->caps |= MMC_CAP_1_8V_DDR;
>
Regards
Dong Aisheng
> --
> 1.9.1
>
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