mmc: sdhci-acpi: Clear amd_sdhci_host on reset

The commit 61d7437 ("mmc: sdhci-acpi: Fix HS400 tuning for AMDI0040")
broke resume for eMMC HS400. When the system suspends the eMMC controller
is powered down. So, on resume we need to reinitialize the controller.
Although, amd_sdhci_host was not getting cleared, so the DLL was never
re-enabled on resume. This results in HS400 being non-functional.

To fix the problem, this change clears the tuned_clock flag, clears the
dll_enabled flag and disables the DLL on reset.

Fixes: 61d7437 ("mmc: sdhci-acpi: Fix HS400 tuning for AMDI0040")
Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20200831150517.1.I93c78bfc6575771bb653c9d3fca5eb018a08417d@changeid
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-acpi.c

@@ -551,12 +551,18 @@ static int amd_select_drive_strength(struct mmc_card *card,
 	return MMC_SET_DRIVER_TYPE_A;
 }
 
-static void sdhci_acpi_amd_hs400_dll(struct sdhci_host *host)
+static void sdhci_acpi_amd_hs400_dll(struct sdhci_host *host, bool enable)
 {
+	struct sdhci_acpi_host *acpi_host = sdhci_priv(host);
+	struct amd_sdhci_host *amd_host = sdhci_acpi_priv(acpi_host);
+
 	/* AMD Platform requires dll setting */
 	sdhci_writel(host, 0x40003210, SDHCI_AMD_RESET_DLL_REGISTER);
 	usleep_range(10, 20);
-	sdhci_writel(host, 0x40033210, SDHCI_AMD_RESET_DLL_REGISTER);
+	if (enable)
+		sdhci_writel(host, 0x40033210, SDHCI_AMD_RESET_DLL_REGISTER);
+
+	amd_host->dll_enabled = enable;
 }
 
 /*
@@ -596,10 +602,8 @@ static void amd_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 
 		/* DLL is only required for HS400 */
 		if (host->timing == MMC_TIMING_MMC_HS400 &&
-		    !amd_host->dll_enabled) {
-			sdhci_acpi_amd_hs400_dll(host);
-			amd_host->dll_enabled = true;
-		}
+		    !amd_host->dll_enabled)
+			sdhci_acpi_amd_hs400_dll(host, true);
 	}
 }
 
@@ -620,10 +624,23 @@ static int amd_sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 	return err;
 }
 
+static void amd_sdhci_reset(struct sdhci_host *host, u8 mask)
+{
+	struct sdhci_acpi_host *acpi_host = sdhci_priv(host);
+	struct amd_sdhci_host *amd_host = sdhci_acpi_priv(acpi_host);
+
+	if (mask & SDHCI_RESET_ALL) {
+		amd_host->tuned_clock = false;
+		sdhci_acpi_amd_hs400_dll(host, false);
+	}
+
+	sdhci_reset(host, mask);
+}
+
 static const struct sdhci_ops sdhci_acpi_ops_amd = {
 	.set_clock	= sdhci_set_clock,
 	.set_bus_width	= sdhci_set_bus_width,
-	.reset		= sdhci_reset,
+	.reset		= amd_sdhci_reset,
 	.set_uhs_signaling = sdhci_set_uhs_signaling,
 };