mmc: support BKOPS feature for eMMC v4.5

Enable eMMC background operations (BKOPS) feature.

If URGENT_BKOPS is set after a response, note that BKOPS
are required. After all I/O requests are finished, run
BKOPS if required. Should read/write operations be requested
during BKOPS, first issue HPI to interrupt the ongoing BKOPS
and then service the request.
If BKOPS-STATUS is upper than LEVEL2, need to check until clear
the BKOPS-STATUS vaule.

If you want to enable this feature, set MMC_CAP2_BKOPS.
And if you want to set the BKOPS_EN bit in ext_csd register,
use the MMC_CAP2_INIT_BKOPS.

Future considerations
 * Check BKOPS_LEVEL=1 and start BKOPS in a preventive manner.
 * Interrupt ongoing BKOPS before powering off the card.
 * How get BKOPS_STATUS value.(periodically send ext_csd command?)

Change-Id: Ia679c661a282072a7e54d10fc59d8ec1cbecae96
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Konstantin Dorfman <kdorfman@codeaurora.org>
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 06539dff..37b5344 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -139,6 +139,7 @@
 #define R1_CURRENT_STATE(x)	((x & 0x00001E00) >> 9)	/* sx, b (4 bits) */
 #define R1_READY_FOR_DATA	(1 << 8)	/* sx, a */
 #define R1_SWITCH_ERROR		(1 << 7)	/* sx, c */
+#define R1_EXCEPTION_EVENT	(1 << 6)	/* sx, a */
 #define R1_APP_CMD		(1 << 5)	/* sr, c */
 #define R1_EXP_EVENT		(1 << 6)	/* sr, a */
 
@@ -284,6 +285,8 @@
 #define EXT_CSD_PARTITION_SUPPORT	160	/* RO */
 #define EXT_CSD_HPI_MGMT		161	/* R/W */
 #define EXT_CSD_RST_N_FUNCTION		162	/* R/W */
+#define EXT_CSD_BKOPS_EN		163	/* R/W */
+#define EXT_CSD_BKOPS_START		164	/* W */
 #define EXT_CSD_SANITIZE_START		165     /* W */
 #define EXT_CSD_WR_REL_PARAM		166	/* RO */
 #define EXT_CSD_ERASE_GROUP_DEF		175	/* R/W */
@@ -316,11 +319,13 @@
 #define EXT_CSD_PWR_CL_200_360		237	/* RO */
 #define EXT_CSD_PWR_CL_DDR_52_195	238	/* RO */
 #define EXT_CSD_PWR_CL_DDR_52_360	239	/* RO */
+#define EXT_CSD_BKOPS_STATUS		246	/* RO */
 #define EXT_CSD_POWER_OFF_LONG_TIME	247	/* RO */
 #define EXT_CSD_GENERIC_CMD6_TIME	248	/* RO */
 #define EXT_CSD_CACHE_SIZE		249	/* RO, 4 bytes */
 #define EXT_CSD_MAX_PACKED_WRITES	500	/* RO */
 #define EXT_CSD_MAX_PACKED_READS	501	/* RO */
+#define EXT_CSD_BKOPS_SUPPORT		502	/* RO */
 #define EXT_CSD_HPI_FEATURES		503	/* RO */
 
 /*
@@ -450,5 +455,16 @@
 #define MMC_SWITCH_MODE_CLEAR_BITS	0x02	/* Clear bits which are 1 in value */
 #define MMC_SWITCH_MODE_WRITE_BYTE	0x03	/* Set target to value */
 
+/*
+ * BKOPS status level
+ */
+#define EXT_CSD_BKOPS_LEVEL_2		0x2
+
+/*
+ * EXCEPTION_EVENT_STATUS field (eMMC4.5)
+ */
+#define EXT_CSD_URGENT_BKOPS		BIT(0)
+#define EXT_CSD_DYNCAP_NEEDED		BIT(1)
+#define EXT_CSD_SYSPOOL_EXHAUSTED	BIT(2)
 #endif  /* MMC_MMC_PROTOCOL_H */