[PATCH] mmc: add support for JESD84-B51B with CSD_REV 9

[PATCH] mmc: add support for JESD84-B51B with CSD_REV 9

[Gregory Baudet]

This patch allows correct version detection for newer eMMC devices
following the 5.1B version of the standard. This new version of the
standard introduces CSD revision 9, and a new decoding rule of the MDT
field in CID register.

Signed-off-by: Gregory Baudet <Gregory.B.dev@gmail.com>
Cc: Peng Fang <peng.fan@nxp.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
---
 drivers/mmc/mmc.c | 3 ++-
 include/mmc.h     | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 7dadff27abe..d9e6860bc74 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -2343,7 +2343,8 @@ static int mmc_startup_v4(struct mmc *mmc)
 		MMC_VERSION_4_41,
 		MMC_VERSION_4_5,
 		MMC_VERSION_5_0,
-		MMC_VERSION_5_1
+		MMC_VERSION_5_1,
+		MMC_VERSION_5_1B
 	};
 
 #if CONFIG_IS_ENABLED(MMC_TINY)
diff --git a/include/mmc.h b/include/mmc.h
index 51d3f2f8dd5..47b0f11877d 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -54,6 +54,7 @@ struct bd_info;
 #define MMC_VERSION_4_5		MAKE_MMC_VERSION(4, 5, 0)
 #define MMC_VERSION_5_0		MAKE_MMC_VERSION(5, 0, 0)
 #define MMC_VERSION_5_1		MAKE_MMC_VERSION(5, 1, 0)
+#define MMC_VERSION_5_1B	MAKE_MMC_VERSION(5, 1, 1)
 
 #define MMC_CAP(mode)		(1 << mode)
 #define MMC_MODE_HS		(MMC_CAP(MMC_HS) | MMC_CAP(SD_HS))
-- 
2.51.0

Re: [PATCH] mmc: add support for JESD84-B51B with CSD_REV 9

[Peng Fan]

On Fri, Jan 30, 2026 at 10:35:39AM +0100, Gregory Baudet wrote:
>This patch allows correct version detection for newer eMMC devices
>following the 5.1B version of the standard. This new version of the
>standard introduces CSD revision 9, and a new decoding rule of the MDT
>field in CID register.
>
>Signed-off-by: Gregory Baudet <Gregory.B.dev@gmail.com>
>Cc: Peng Fang <peng.fan@nxp.com>
>Cc: Jaehoon Chung <jh80.chung@samsung.com>
>---
> drivers/mmc/mmc.c | 3 ++-
> include/mmc.h     | 1 +
> 2 files changed, 3 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
>index 7dadff27abe..d9e6860bc74 100644
>--- a/drivers/mmc/mmc.c
>+++ b/drivers/mmc/mmc.c
>@@ -2343,7 +2343,8 @@ static int mmc_startup_v4(struct mmc *mmc)
> 		MMC_VERSION_4_41,
> 		MMC_VERSION_4_5,
> 		MMC_VERSION_5_0,
>-		MMC_VERSION_5_1
>+		MMC_VERSION_5_1,
>+		MMC_VERSION_5_1B
> 	};
> 
> #if CONFIG_IS_ENABLED(MMC_TINY)
>diff --git a/include/mmc.h b/include/mmc.h
>index 51d3f2f8dd5..47b0f11877d 100644
>--- a/include/mmc.h
>+++ b/include/mmc.h
>@@ -54,6 +54,7 @@ struct bd_info;
> #define MMC_VERSION_4_5		MAKE_MMC_VERSION(4, 5, 0)
> #define MMC_VERSION_5_0		MAKE_MMC_VERSION(5, 0, 0)
> #define MMC_VERSION_5_1		MAKE_MMC_VERSION(5, 1, 0)
>+#define MMC_VERSION_5_1B	MAKE_MMC_VERSION(5, 1, 1)
> 
> #define MMC_CAP(mode)		(1 << mode)
> #define MMC_MODE_HS		(MMC_CAP(MMC_HS) | MMC_CAP(SD_HS))

The changes looks good to me. But I would see whether this has been
tested on real devices.

Thanks,
Peng

>-- 
>2.51.0
>
>