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>

4 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 6dfb293326e2..5294ddf382ae 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -50,6 +50,7 @@ struct mmc_ext_csd {
         u8                      rel_sectors;
         u8                      rel_param;
         u8                      part_config;
+        u8                      rst_n_function;
         unsigned int            part_time;              /* Units: ms */
         unsigned int            sa_timeout;             /* Units: 100ns */
         unsigned int            hs_max_dtr;
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index b8b1b7a311f1..56e5625b6f41 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -162,6 +162,9 @@ extern int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,
 extern unsigned int mmc_calc_max_discard(struct mmc_card *card);
 
 extern int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen);
+extern int mmc_hw_reset(struct mmc_host *host);
+extern int mmc_hw_reset_check(struct mmc_host *host);
+extern int mmc_can_reset(struct mmc_card *card);
 
 extern void mmc_set_data_timeout(struct mmc_data *, const struct mmc_card *);
 extern unsigned int mmc_align_data_size(struct mmc_card *, unsigned int);
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 340cc0c9409f..b2aefea97048 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -151,6 +151,7 @@ struct mmc_host_ops {
         int     (*execute_tuning)(struct mmc_host *host);
         void    (*enable_preset_value)(struct mmc_host *host, bool enable);
         int     (*select_drive_strength)(unsigned int max_dtr, int host_drv, int card_drv);
+        void    (*hw_reset)(struct mmc_host *host);
 };
 
 struct mmc_card;
@@ -233,6 +234,7 @@ struct mmc_host {
 #define MMC_CAP_MAX_CURRENT_600 (1 << 28)       /* Host max current limit is 600mA */
 #define MMC_CAP_MAX_CURRENT_800 (1 << 29)       /* Host max current limit is 800mA */
 #define MMC_CAP_CMD23           (1 << 30)       /* CMD23 supported. */
+#define MMC_CAP_HW_RESET        (1 << 31)       /* Hardware reset */
 
         mmc_pm_flag_t           pm_caps;        /* supported pm features */
 
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
  */