The controller has different timings for MMC_TIMING_UHS_DDR50 and
MMC_TIMING_MMC_DDR52. Configuring the controller with SDHCI_CTRL_UHS_DDR50,
when MMC_TIMING_MMC_DDR52 timings are requested, is not correct and can
lead to unexpected behavior.
Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx>
Fixes: bb5f8ea4d514 ("mmc: sdhci-of-at91: introduce driver for the Atmel SDMMC")
Cc: <stable@xxxxxxxxxxxxxxx> # 4.4+
---
Hi,
Here is the proper fix (I hope!) to the issue I have since commit e173f8911f09
("mmc: core: Update CMD13 polling policy when switch to HS DDR mode"). This
commit was probably not the root cause but causes some side effect due to a
bad timing configuration.
I can't explain how it was working before but for sure I was not configuring
properly the controller timings.
Regards
drivers/mmc/host/sdhci-of-at91.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
index 814571f..7611fd6 100644
--- a/drivers/mmc/host/sdhci-of-at91.c
+++ b/drivers/mmc/host/sdhci-of-at91.c
@@ -29,6 +29,8 @@
#include "sdhci-pltfm.h"
+#define SDMMC_MC1R 0x204
+#define SDMMC_MC1R_DDR BIT(3)
#define SDMMC_CACR 0x230
#define SDMMC_CACR_CAPWREN BIT(0)
#define SDMMC_CACR_KEY (0x46 << 8)
@@ -101,11 +103,18 @@ static void sdhci_at91_set_power(struct sdhci_host *host, unsigned char mode,
sdhci_set_power_noreg(host, mode, vdd);
}
+void sdhci_at91_set_uhs_signaling(struct sdhci_host *host, unsigned int timing)
+{
+ if (timing == MMC_TIMING_MMC_DDR52)
+ sdhci_writeb(host, SDMMC_MC1R_DDR, SDMMC_MC1R);
+ sdhci_set_uhs_signaling(host, timing);
+}
+
static const struct sdhci_ops sdhci_at91_sama5d2_ops = {
.set_clock = sdhci_at91_set_clock,
.set_bus_width = sdhci_set_bus_width,
.reset = sdhci_reset,
- .set_uhs_signaling = sdhci_set_uhs_signaling,
+ .set_uhs_signaling = sdhci_at91_set_uhs_signaling,
.set_power = sdhci_at91_set_power,
};
--
2.9.0