mmc: core: expose RPMB partition only for CMD23 capable hosts

commit d0123ccac55088811bde4f76c4a3fdbd39c3cfba upstream.

SET_BLOCK_COUNT CMD23 is needed for all access to RPMB partition.  If
block count is not set by CMD23, all subsequent read/write commands fail
as per eMMC specification. So, If the host does not support CMD23, do not
expose RPMB partition.

Accessing RPMB partition can cause hang / huge delay for hosts which do
not support CMD23.

Signed-off-by: Balaji T K <balajitk@ti.com>
Reported-and-Tested-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Chris Ball <cjb@laptop.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 e6e39111e05b416623f830060fd8fca86f44edf5..089e8ea34812516612000faab9ec79d530cf8f51 100644 (file)
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -496,7 +496,7 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
                 * RPMB regions are defined in multiples of 128K.
                 */
                card->ext_csd.raw_rpmb_size_mult = ext_csd[EXT_CSD_RPMB_MULT];
-               if (ext_csd[EXT_CSD_RPMB_MULT]) {
+               if (ext_csd[EXT_CSD_RPMB_MULT] && mmc_host_cmd23(card->host)) {
                        mmc_part_add(card, ext_csd[EXT_CSD_RPMB_MULT] << 17,
                                EXT_CSD_PART_CONFIG_ACC_RPMB,
                                "rpmb", 0, false,