mmc: core: add eMMC hardware reset support

eMMC's may have a hardware reset line.  This patch provides a
host controller operation to implement hardware reset and
a function to reset and reinitialize the card.  Also, for MMC,
the reset is always performed before initialization.

The host must set the new host capability MMC_CAP_HW_RESET
to enable hardware reset.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 5a794cb503ea..ed8fca890ee2 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -272,6 +272,7 @@ struct _mmc_csd {
 
 #define EXT_CSD_PARTITION_ATTRIBUTE     156     /* R/W */
 #define EXT_CSD_PARTITION_SUPPORT       160     /* RO */
+#define EXT_CSD_RST_N_FUNCTION          162     /* R/W */
 #define EXT_CSD_WR_REL_PARAM            166     /* RO */
 #define EXT_CSD_ERASE_GROUP_DEF         175     /* R/W */
 #define EXT_CSD_PART_CONFIG             179     /* R/W */
@@ -328,6 +329,9 @@ struct _mmc_csd {
 #define EXT_CSD_SEC_BD_BLK_EN   BIT(2)
 #define EXT_CSD_SEC_GB_CL_EN    BIT(4)
 
+#define EXT_CSD_RST_N_EN_MASK   0x3
+#define EXT_CSD_RST_N_ENABLED   1       /* RST_n is enabled on card */
+
 /*
  * MMC_SWITCH access modes
  */