mmc: export eMMC4.4 enhanced area details to sysfs

Enhanced area feature is a new feature defined in eMMC4.4 standard. This
user data area provides higher performance/reliability, at the expense
of using twice the effective media space due to the area using SLC.

The MMC driver now reads out the enhanced area offset and size and adds
them to the device attributes in sysfs. Enabling the enhanced area can
only be done once, and should be done in manufacturing. To use this
feature, bit ERASE_GRP_DEF should also be set.

Documentation/ABI/testing/sysfs-devices-mmc describes the two new
attributes.

Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
Reviewed-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

2 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 8ce082781ccb..4652cf9c5442 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -54,6 +54,9 @@ struct mmc_ext_csd {
         unsigned int            sec_trim_mult;  /* Secure trim multiplier  */
         unsigned int            sec_erase_mult; /* Secure erase multiplier */
         unsigned int            trim_timeout;           /* In milliseconds */
+        bool                    enhanced_area_en;       /* enable bit */
+        unsigned long long      enhanced_area_offset;   /* Units: Byte */
+        unsigned int            enhanced_area_size;     /* Units: KB */
 };
 
 struct sd_scr {
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 612301f85d14..264ba5451e3b 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -253,6 +253,8 @@ struct _mmc_csd {
  * EXT_CSD fields
  */
 
+#define EXT_CSD_PARTITION_ATTRIBUTE     156     /* R/W */
+#define EXT_CSD_PARTITION_SUPPORT       160     /* RO */
 #define EXT_CSD_ERASE_GROUP_DEF         175     /* R/W */
 #define EXT_CSD_ERASED_MEM_CONT         181     /* RO */
 #define EXT_CSD_BUS_WIDTH               183     /* R/W */
@@ -262,6 +264,7 @@ struct _mmc_csd {
 #define EXT_CSD_CARD_TYPE               196     /* RO */
 #define EXT_CSD_SEC_CNT                 212     /* RO, 4 bytes */
 #define EXT_CSD_S_A_TIMEOUT             217     /* RO */
+#define EXT_CSD_HC_WP_GRP_SIZE          221     /* RO */
 #define EXT_CSD_ERASE_TIMEOUT_MULT      223     /* RO */
 #define EXT_CSD_HC_ERASE_GRP_SIZE       224     /* RO */
 #define EXT_CSD_SEC_TRIM_MULT           229     /* RO */