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.
Previously the tuned clock was not getting disabled when switching to
DDR52 which is part of the HS400 tuning sequence.
Fixes: 34597a3f60b1 ("mmc: sdhci-acpi: Add support for ACPI HID of AMD Controller with HS400")
Signed-off-by: Raul E Rangel <rrangel@xxxxxxxxxxxx>
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
Changes in v2:
- Added static to amd_sdhci_execute_tuning
drivers/mmc/host/sdhci-acpi.c | 68 +++++++++++++++++++++++++++++------
1 file changed, 58 insertions(+), 10 deletions(-)
diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c
index 48ecbd0b180d8..a832d917e2fe3 100644
--- a/drivers/mmc/host/sdhci-acpi.c
+++ b/drivers/mmc/host/sdhci-acpi.c
@@ -535,6 +535,11 @@ 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
@@ -555,26 +560,67 @@ static void sdhci_acpi_amd_hs400_dll(struct sdhci_host *host)
}
/*
- * 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) {
+ trace_printk("%s: Enabling DLL\n", __func__);
+ sdhci_acpi_amd_hs400_dll(host);
+ amd_host->dll_enabled = 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 const struct sdhci_ops sdhci_acpi_ops_amd = {
.set_clock = sdhci_set_clock,
.set_bus_width = sdhci_set_bus_width,
@@ -602,6 +648,7 @@ 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;
}
@@ -613,6 +660,7 @@ 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 {
--
2.28.0.220.ged08abb693-goog
