1 files changed, 77 insertions, 13 deletions

diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c
index 01fc437ed965..b2d924c5e82e 100644
--- a/drivers/mmc/host/sdhci-acpi.c
+++ b/drivers/mmc/host/sdhci-acpi.c
@@ -532,6 +532,11 @@ static const struct sdhci_acpi_slot sdhci_acpi_slot_qcom_sd = {
 	.caps    = MMC_CAP_NONREMOVABLE,
 };
 
+struct amd_sdhci_host {
+	bool	tuned_clock;
+	bool	dll_enabled;
+};
+
 /* AMD sdhci reset dll register. */
 #define SDHCI_AMD_RESET_DLL_REGISTER    0x908
 
@@ -542,39 +547,96 @@ 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;
 }
 
 /*
- * For AMD Platform it is required to disable the tuning
- * bit first controller to bring to HS Mode from HS200
- * mode, later enable to tune to HS400 mode.
+ * The initialization sequence for HS400 is:
+ *     HS->HS200->Perform Tuning->HS->HS400
+ *
+ * The re-tuning sequence is:
+ *     HS400->DDR52->HS->HS200->Perform Tuning->HS->HS400
+ *
+ * The AMD eMMC Controller can only use the tuned clock while in HS200 and HS400
+ * mode. If we switch to a different mode, we need to disable the tuned clock.
+ * If we have previously performed tuning and switch back to HS200 or
+ * HS400, we can re-enable the tuned clock.
+ *
  */
 static void amd_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 {
 	struct sdhci_host *host = mmc_priv(mmc);
+	struct sdhci_acpi_host *acpi_host = sdhci_priv(host);
+	struct amd_sdhci_host *amd_host = sdhci_acpi_priv(acpi_host);
 	unsigned int old_timing = host->timing;
+	u16 val;
 
 	sdhci_set_ios(mmc, ios);
-	if (old_timing == MMC_TIMING_MMC_HS200 &&
-	    ios->timing == MMC_TIMING_MMC_HS)
-		sdhci_writew(host, 0x9, SDHCI_HOST_CONTROL2);
-	if (old_timing != MMC_TIMING_MMC_HS400 &&
-	    ios->timing == MMC_TIMING_MMC_HS400) {
-		sdhci_writew(host, 0x80, SDHCI_HOST_CONTROL2);
-		sdhci_acpi_amd_hs400_dll(host);
+
+	if (old_timing != host->timing && amd_host->tuned_clock) {
+		if (host->timing == MMC_TIMING_MMC_HS400 ||
+		    host->timing == MMC_TIMING_MMC_HS200) {
+			val = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+			val |= SDHCI_CTRL_TUNED_CLK;
+			sdhci_writew(host, val, SDHCI_HOST_CONTROL2);
+		} else {
+			val = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+			val &= ~SDHCI_CTRL_TUNED_CLK;
+			sdhci_writew(host, val, SDHCI_HOST_CONTROL2);
+		}
+
+		/* DLL is only required for HS400 */
+		if (host->timing == MMC_TIMING_MMC_HS400 &&
+		    !amd_host->dll_enabled)
+			sdhci_acpi_amd_hs400_dll(host, true);
+	}
+}
+
+static int amd_sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
+{
+	int err;
+	struct sdhci_host *host = mmc_priv(mmc);
+	struct sdhci_acpi_host *acpi_host = sdhci_priv(host);
+	struct amd_sdhci_host *amd_host = sdhci_acpi_priv(acpi_host);
+
+	amd_host->tuned_clock = false;
+
+	err = sdhci_execute_tuning(mmc, opcode);
+
+	if (!err && !host->tuning_err)
+		amd_host->tuned_clock = true;
+
+	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,
 };
 
@@ -598,6 +660,7 @@ static int sdhci_acpi_emmc_amd_probe_slot(struct platform_device *pdev,
 
 	host->mmc_host_ops.select_drive_strength = amd_select_drive_strength;
 	host->mmc_host_ops.set_ios = amd_set_ios;
+	host->mmc_host_ops.execute_tuning = amd_sdhci_execute_tuning;
 	return 0;
 }
 
@@ -609,6 +672,7 @@ static const struct sdhci_acpi_slot sdhci_acpi_slot_amd_emmc = {
 			  SDHCI_QUIRK_32BIT_ADMA_SIZE,
 	.quirks2	= SDHCI_QUIRK2_BROKEN_64_BIT_DMA,
 	.probe_slot     = sdhci_acpi_emmc_amd_probe_slot,
+	.priv_size	= sizeof(struct amd_sdhci_host),
 };
 
 struct sdhci_acpi_uid_slot {