mmc: sdhci-esdhc-imx: remove the 100MHz limitation for Strobe DLL

For some eMMC, after switch to HS400ES mode, it need to config the strobe
dll target dealy even if the clock is 50MHZ or 25MHz, otherwise will meet
CMD index/crc error when send CMD13 to check the switch status.

[    2.473915] IRQ status 0x000a8001
[    2.473934] mmc2: mmc_select_hs400es failed, error -84
[    2.473938] mmc2: error -84 whilst initialising MMC card
Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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

@@ -144,8 +144,6 @@
  * 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
 
 struct esdhc_soc_data {
 	u32 flags;
@@ -939,39 +937,35 @@ static int esdhc_change_pinstate(struct sdhci_host *host,
  * edge of data_strobe line. Due to the time delay between CLK line and
  * data_strobe line, if the delay time is larger than one clock cycle,
  * then CLK and data_strobe line will be misaligned, read error shows up.
- * So when the CLK is higher than 100MHz, each clock cycle is short enough,
- * host should configure the delay target.
  */
 static void esdhc_set_strobe_dll(struct sdhci_host *host)
 {
 	u32 v;
 
-	if (host->mmc->actual_clock > ESDHC_STROBE_DLL_CLK_FREQ) {
-		/* disable clock before enabling strobe dll */
-		writel(readl(host->ioaddr + ESDHC_VENDOR_SPEC) &
-		       ~ESDHC_VENDOR_SPEC_FRC_SDCLK_ON,
-		       host->ioaddr + ESDHC_VENDOR_SPEC);
+	/* disable clock before enabling strobe dll */
+	writel(readl(host->ioaddr + ESDHC_VENDOR_SPEC) &
+		~ESDHC_VENDOR_SPEC_FRC_SDCLK_ON,
+		host->ioaddr + ESDHC_VENDOR_SPEC);
 
-		/* force a reset on strobe dll */
-		writel(ESDHC_STROBE_DLL_CTRL_RESET,
-			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 |
-			(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);
-		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))
-			dev_warn(mmc_dev(host->mmc),
-				"warning! HS400 strobe DLL status SLV not lock!\n");
-	}
+	/* force a reset on strobe dll */
+	writel(ESDHC_STROBE_DLL_CTRL_RESET,
+		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 |
+		(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);
+	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))
+		dev_warn(mmc_dev(host->mmc),
+		"warning! HS400 strobe DLL status SLV not lock!\n");
 }
 
 static void esdhc_reset_tuning(struct sdhci_host *host)