On 15/11/19 1:18 PM, haibo.chen@xxxxxxx wrote:
> From: Haibo Chen <haibo.chen@xxxxxxx>
>
> strobe-dll-delay-target is the delay cell add on the strobe line.
> Strobe line the the uSDHC loopback read clock which is use in HS400
> mode. Different strobe-dll-delay-target may need to set for different
> board/SoC. If this delay cell is not set to an appropriate value,
> we may see some read operation meet CRC error after HS400 mode select
> which already pass the tuning.
>
> This patch add the strobe-dll-delay-target setting in driver, so that
> user can easily config this delay cell in dts file.
>
> Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
> drivers/mmc/host/sdhci-esdhc-imx.c | 12 +++++++++++-
> include/linux/platform_data/mmc-esdhc-imx.h | 1 +
> 2 files changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index 448b29b2da62..2ed945f5c259 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -73,6 +73,7 @@
> #define ESDHC_STROBE_DLL_CTRL 0x70
> #define ESDHC_STROBE_DLL_CTRL_ENABLE (1 << 0)
> #define ESDHC_STROBE_DLL_CTRL_RESET (1 << 1)
> +#define ESDHC_STROBE_DLL_CTRL_SLV_DLY_TARGET_DEFAULT 0x7
> #define ESDHC_STROBE_DLL_CTRL_SLV_DLY_TARGET_SHIFT 3
> #define ESDHC_STROBE_DLL_CTRL_SLV_UPDATE_INT_DEFAULT (4 << 20)
>
> @@ -995,6 +996,9 @@ static int esdhc_change_pinstate(struct sdhci_host *host,
> */
> static void esdhc_set_strobe_dll(struct sdhci_host *host)
> {
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host);
> + u32 strobe_delay;
> u32 v;
>
> /* disable clock before enabling strobe dll */
> @@ -1012,9 +1016,13 @@ static void esdhc_set_strobe_dll(struct sdhci_host *host)
> * enable strobe dll ctrl and adjust the delay target
> * for the uSDHC loopback read clock
> */
> + if (imx_data->boarddata.strobe_dll_delay_target)
> + strobe_delay = imx_data->boarddata.strobe_dll_delay_target;
> + else
> + strobe_delay = ESDHC_STROBE_DLL_CTRL_SLV_DLY_TARGET_DEFAULT;
> v = ESDHC_STROBE_DLL_CTRL_ENABLE |
> ESDHC_STROBE_DLL_CTRL_SLV_UPDATE_INT_DEFAULT |
> - (7 << ESDHC_STROBE_DLL_CTRL_SLV_DLY_TARGET_SHIFT);
> + (strobe_delay << ESDHC_STROBE_DLL_CTRL_SLV_DLY_TARGET_SHIFT);
> writel(v, host->ioaddr + ESDHC_STROBE_DLL_CTRL);
> /* wait 5us to make sure strobe dll status register stable */
> udelay(5);
> @@ -1340,6 +1348,8 @@ sdhci_esdhc_imx_probe_dt(struct platform_device *pdev,
> of_property_read_u32(np, "fsl,tuning-start-tap",
> &boarddata->tuning_start_tap);
>
> + of_property_read_u32(np, "fsl,strobe-dll-delay-target",
> + &boarddata->strobe_dll_delay_target);
> if (of_find_property(np, "no-1-8-v", NULL))
> host->quirks2 |= SDHCI_QUIRK2_NO_1_8_V;
>
> diff --git a/include/linux/platform_data/mmc-esdhc-imx.h b/include/linux/platform_data/mmc-esdhc-imx.h
> index 6c006078c8a1..0434f68eda86 100644
> --- a/include/linux/platform_data/mmc-esdhc-imx.h
> +++ b/include/linux/platform_data/mmc-esdhc-imx.h
> @@ -37,5 +37,6 @@ struct esdhc_platform_data {
> unsigned int delay_line;
> unsigned int tuning_step; /* The delay cell steps in tuning procedure */
> unsigned int tuning_start_tap; /* The start delay cell point in tuning procedure */
> + unsigned int strobe_dll_delay_target; /* The delay cell for strobe pad (read clock) */
> };
> #endif /* __ASM_ARCH_IMX_ESDHC_H */
>
