On 29/04/19 11:55 AM, BOUGH CHEN wrote:
> Add HS400 support for iMX7ULP B0.
>
> According to IC suggest, need to clear the STROBE_DLL_CTRL_RESET
> before any setting of STROBE_DLL_CTRL register.
>
> USDHC has register bits(bit[27~20] of register STROBE_DLL_CTRL)
> for slave sel value. If this register bits value is 0, it needs
> 256 ref_clk cycles to update slave sel value. IC suggest to set
> bit[27~20] to 0x4, it only need 4 ref_clk cycle to update slave
> sel value. This will short the lock time of slave.
>
> i.MX7ULP B0 will need more time to lock the REF and SLV, so change
> to add 5us delay.
>
> Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
> drivers/mmc/host/sdhci-esdhc-imx.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index 053e8586d557..c391510e9ef4 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -74,6 +74,7 @@
> #define ESDHC_STROBE_DLL_CTRL_ENABLE (1 << 0)
> #define ESDHC_STROBE_DLL_CTRL_RESET (1 << 1)
> #define ESDHC_STROBE_DLL_CTRL_SLV_DLY_TARGET_SHIFT 3
> +#define ESDHC_STROBE_DLL_CTRL_SLV_UPDATE_INT_DEFAULT (4 << 20)
>
> #define ESDHC_STROBE_DLL_STATUS 0x74
> #define ESDHC_STROBE_DLL_STS_REF_LOCK (1 << 1)
> @@ -210,7 +211,7 @@ static const struct esdhc_soc_data usdhc_imx7d_data = {
> static struct esdhc_soc_data usdhc_imx7ulp_data = {
> .flags = ESDHC_FLAG_USDHC | ESDHC_FLAG_STD_TUNING
> | ESDHC_FLAG_HAVE_CAP1 | ESDHC_FLAG_HS200
> - | ESDHC_FLAG_PMQOS,
> + | ESDHC_FLAG_PMQOS | ESDHC_FLAG_HS400,
> };
>
> static struct esdhc_soc_data usdhc_imx8qxp_data = {
> @@ -994,15 +995,19 @@ static void esdhc_set_strobe_dll(struct sdhci_host *host)
> /* force a reset on strobe dll */
> writel(ESDHC_STROBE_DLL_CTRL_RESET,
> host->ioaddr + ESDHC_STROBE_DLL_CTRL);
> + /* clear the reset bit on strobe dll before any setting */
> + writel(0, host->ioaddr + ESDHC_STROBE_DLL_CTRL);
> +
> /*
> * enable strobe dll ctrl and adjust the delay target
> * for the uSDHC loopback read clock
> */
> v = ESDHC_STROBE_DLL_CTRL_ENABLE |
> + ESDHC_STROBE_DLL_CTRL_SLV_UPDATE_INT_DEFAULT |
> (7 << ESDHC_STROBE_DLL_CTRL_SLV_DLY_TARGET_SHIFT);
> writel(v, host->ioaddr + ESDHC_STROBE_DLL_CTRL);
> - /* wait 1us to make sure strobe dll status register stable */
> - udelay(1);
> + /* wait 5us to make sure strobe dll status register stable */
> + udelay(5);
> v = readl(host->ioaddr + ESDHC_STROBE_DLL_STATUS);
> if (!(v & ESDHC_STROBE_DLL_STS_REF_LOCK))
> dev_warn(mmc_dev(host->mmc),
>
