For eMMC v4 and newer that is smaller than 2 GiB, the JEDEC JESD84-B51
section 6.2.4 Configure partitions indicates that EXT_CSD SEC_COUNT
should not be used to determine device size, and instead device size
should be calculated from C_SIZE and C_SIZE_MULT.
This is not exactly accurate, the 2 GiB limit is not a hard line,
there are eMMC devices which are smaller than 2 GiB and still
require device size to be determined from EXT_CSD SEC_COUNT. The
hard line is instead OCR HCS bit, which indicates whether the device
is byte or sector addressed, the former applies to most devices
below 2 GiB, and the later applies mostly to devices above 2 GiB.
However, there are a couple of devices which are smaller than 2 GiB
and still set the OCR HCS bit to indicate they are sector addressed,
and therefore the size calculation for those devices should also
use EXT_CSD SEC_COUNT . Use mmc->high_capacity flag to discern the
devices instead of arbitrary 2 GiB limit. The mmc->high_capacity flag
reflects the OCR HCS bit state.
Fixes: 639b7827d1ca ("mmc: fix the condition for MMC version 4")
Signed-off-by: Marek Vasut <[email protected]>
---
Cc: Heinrich Schuchardt <[email protected]>
Cc: Jaehoon Chung <[email protected]>
Cc: Peng Fan <[email protected]>
Cc: Quentin Schulz <[email protected]>
Cc: Ronald Wahl <[email protected]>
Cc: Sean Anderson <[email protected]>
Cc: Simon Glass <[email protected]>
Cc: Tim Harvey <[email protected]>
Cc: Tom Rini <[email protected]>
Cc: Yoshihiro Shimoda <[email protected]>
Cc: [email protected]
Cc: [email protected]
---
drivers/mmc/mmc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 799586891af..31a72366206 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -2376,7 +2376,7 @@ static int mmc_startup_v4(struct mmc *mmc)
| ext_csd[EXT_CSD_SEC_CNT + 2] << 16
| ext_csd[EXT_CSD_SEC_CNT + 3] << 24;
capacity *= MMC_MAX_BLOCK_LEN;
- if ((capacity >> 20) > 2 * 1024)
+ if (mmc->high_capacity)
mmc->capacity_user = capacity;
}
--
2.45.2
