mmc: core: Capture correct oemid-bits for eMMC cards

commit 84ee19bffc9306128cd0f1c650e89767079efeff upstream.

The OEMID is an 8-bit binary number rather than 16-bit as the current code
parses for. The OEMID occupies bits [111:104] in the CID register, see the
eMMC spec JESD84-B51 paragraph 7.2.3. It seems that the 16-bit comes from
the legacy MMC specs (v3.31 and before).

Let's fix the parsing by simply move to use 8-bit instead of 16-bit. This
means we ignore the impact on some of those old MMC cards that may be out
there, but on the other hand this shouldn't be a problem as the OEMID seems
not be an important feature for these cards.

Signed-off-by: Avri Altman <avri.altman@wdc.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230927071500.1791882-1-avri.altman@wdc.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index d805f84507198351d285ef94a214f713fcc56707..5074b3ce38ea0ef8012ff42db4dac228f0ee7efc 100644 (file)
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -96,7 +96,7 @@ static int mmc_decode_cid(struct mmc_card *card)
        case 3: /* MMC v3.1 - v3.3 */
        case 4: /* MMC v4 */
                card->cid.manfid        = UNSTUFF_BITS(resp, 120, 8);
-               card->cid.oemid         = UNSTUFF_BITS(resp, 104, 16);
+               card->cid.oemid         = UNSTUFF_BITS(resp, 104, 8);
                card->cid.prod_name[0]  = UNSTUFF_BITS(resp, 96, 8);
                card->cid.prod_name[1]  = UNSTUFF_BITS(resp, 88, 8);
                card->cid.prod_name[2]  = UNSTUFF_BITS(resp, 80, 8);