Re: [PATCH v2 2/3] mmc: sdhci-esdhc-imx: add SD clock limitation for imx6ull

[Ulf Hansson <ulf.hansson@linaro.org>]

On Fri, 28 Dec 2018 at 04:26, BOUGH CHEN <haibo.chen@nxp.com> wrote:
>
> i.MX6ULL has errata ERR010450, point out that due to SOC I/O
> timing limitation, for eMMC HS200 and SD/SDIO 3.0 SDR104, the
> clock rate can't exceed 150MHz. And for eMMC DDR52 and SD/SDIO
> DDR50 mode, the clock rate can't exceed 45MHz.
>
> This patch add this limit for imx6ull.
>
> Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
> Acked-by: Adrian Hunter <adrian.hunter@intel.com>

Applied for next (I amended the patch by fixing a trivial conflict and
made the struct "const").

Kind regards
Uffe


> ---
>  drivers/mmc/host/sdhci-esdhc-imx.c | 21 ++++++++++++++++++++-
>  1 file changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index 7cfcc8618e45..e1d9b2985979 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -138,7 +138,11 @@
>  #define ESDHC_FLAG_HS200               BIT(8)
>  /* The IP supports HS400 mode */
>  #define ESDHC_FLAG_HS400               BIT(9)
> -
> +/* The IP has errata ERR010450
> + * uSDHC: Due to the I/O timing limit, for SDR mode, SD card clock can't
> + * exceed 150MHz, for DDR mode, SD card clock can't exceed 45MHz.
> + */
> +#define ESDHC_FLAG_ERR010450           BIT(10)
>  /* A clock frequency higher than this rate requires strobe dll control */
>  #define ESDHC_STROBE_DLL_CLK_FREQ      100000000
>
> @@ -177,6 +181,12 @@ static struct esdhc_soc_data usdhc_imx6sx_data = {
>                         | ESDHC_FLAG_HAVE_CAP1 | ESDHC_FLAG_HS200,
>  };
>
> +static struct esdhc_soc_data usdhc_imx6ull_data = {
> +       .flags = ESDHC_FLAG_USDHC | ESDHC_FLAG_STD_TUNING
> +                       | ESDHC_FLAG_HAVE_CAP1 | ESDHC_FLAG_HS200
> +                       | ESDHC_FLAG_ERR010450,
> +};
> +
>  static struct esdhc_soc_data usdhc_imx7d_data = {
>         .flags = ESDHC_FLAG_USDHC | ESDHC_FLAG_STD_TUNING
>                         | ESDHC_FLAG_HAVE_CAP1 | ESDHC_FLAG_HS200
> @@ -227,6 +237,7 @@ static const struct of_device_id imx_esdhc_dt_ids[] = {
>         { .compatible = "fsl,imx6sx-usdhc", .data = &usdhc_imx6sx_data, },
>         { .compatible = "fsl,imx6sl-usdhc", .data = &usdhc_imx6sl_data, },
>         { .compatible = "fsl,imx6q-usdhc", .data = &usdhc_imx6q_data, },
> +       { .compatible = "fsl,imx6ull-usdhc", .data = &usdhc_imx6ull_data, },
>         { .compatible = "fsl,imx7d-usdhc", .data = &usdhc_imx7d_data, },
>         { /* sentinel */ }
>  };
> @@ -733,6 +744,14 @@ static inline void esdhc_pltfm_set_clock(struct sdhci_host *host,
>                 | ESDHC_CLOCK_MASK);
>         sdhci_writel(host, temp, ESDHC_SYSTEM_CONTROL);
>
> +       if (imx_data->socdata->flags & ESDHC_FLAG_ERR010450) {
> +               unsigned int max_clock;
> +
> +               max_clock = imx_data->is_ddr ? 45000000 : 150000000;
> +
> +               clock = min(clock, max_clock);
> +       }
> +
>         while (host_clock / (16 * pre_div * ddr_pre_div) > clock &&
>                         pre_div < 256)
>                 pre_div *= 2;
> --
> 2.17.1
>