mmc: sdhci-esdhc-imx: optimize the strobe dll setting

After set the STROBE SLV delay target value, it need to wait some
time to let the usdhc lock the REF and SLV clock. In normal case,
1~2us is enough for imx8/imx6 and imx7d, and 4~5us is enough for
imx7ulp, but when do reboot stress test or do the bind/unbind stress
test, sometimes need to wait about 10us to get the status lock.

This patch optimize delay handle method, only print the warning
message if the status is still not lock after 1ms delay.
Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/1582100757-20683-3-git-send-email-haibo.chen@nxp.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-esdhc-imx.c

@@ -1019,6 +1019,7 @@ static void esdhc_set_strobe_dll(struct sdhci_host *host)
 	struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host);
 	u32 strobe_delay;
 	u32 v;
+	int ret;
 
 	/* disable clock before enabling strobe dll */
 	writel(readl(host->ioaddr + ESDHC_VENDOR_SPEC) &
@@ -1044,15 +1045,13 @@ static void esdhc_set_strobe_dll(struct sdhci_host *host)
 		ESDHC_STROBE_DLL_CTRL_SLV_UPDATE_INT_DEFAULT |
 		(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);
-	v = readl(host->ioaddr + ESDHC_STROBE_DLL_STATUS);
-	if (!(v & ESDHC_STROBE_DLL_STS_REF_LOCK))
-		dev_warn(mmc_dev(host->mmc),
-		"warning! HS400 strobe DLL status REF not lock!\n");
-	if (!(v & ESDHC_STROBE_DLL_STS_SLV_LOCK))
+
+	/* wait max 50us to get the REF/SLV lock */
+	ret = readl_poll_timeout(host->ioaddr + ESDHC_STROBE_DLL_STATUS, v,
+		((v & ESDHC_STROBE_DLL_STS_REF_LOCK) && (v & ESDHC_STROBE_DLL_STS_SLV_LOCK)), 1, 50);
+	if (ret == -ETIMEDOUT)
 		dev_warn(mmc_dev(host->mmc),
-		"warning! HS400 strobe DLL status SLV not lock!\n");
+		"warning! HS400 strobe DLL status REF/SLV not lock in 50us, STROBE DLL status is %x!\n", v);
 }
 
 static void esdhc_reset_tuning(struct sdhci_host *host)