[PATCH 1/2] mmc: fsl_esdhc: Set fallback mode to 1-bit

Pali Rohár pali at kernel.org
Wed May 11 20:27:12 CEST 2022


8-bit mode is not supported by SD cards and on P2020 are four SDHC pins
shared with SPI (so if P2020 board have also SPI then only 4-bit SDHC mode
is provided). So 8-bit SDHC mode is really bad default.

When max bus width is not provided then set mode to 1-bit. This mode is
supported by all cards, so it is the best option for fallback mode.

Also P2020 bootrom sets mode to 1-bit when booting from SD/MMC card.

Signed-off-by: Pali Rohár <pali at kernel.org>
---
 drivers/mmc/fsl_esdhc.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
index 3b3587bd8d72..834f8933b0c6 100644
--- a/drivers/mmc/fsl_esdhc.c
+++ b/drivers/mmc/fsl_esdhc.c
@@ -963,9 +963,8 @@ int fsl_esdhc_initialize(struct bd_info *bis, struct fsl_esdhc_cfg *cfg)
 	} else if (cfg->max_bus_width == 1) {
 		mmc_cfg->host_caps |= MMC_MODE_1BIT;
 	} else {
-		mmc_cfg->host_caps |= MMC_MODE_1BIT | MMC_MODE_4BIT |
-				      MMC_MODE_8BIT;
-		printf("No max bus width provided. Assume 8-bit supported.\n");
+		mmc_cfg->host_caps |= MMC_MODE_1BIT;
+		printf("No max bus width provided. Fallback to 1-bit mode.\n");
 	}
 
 	if (IS_ENABLED(CONFIG_ESDHC_DETECT_8_BIT_QUIRK))
-- 
2.20.1



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