mmc: support BKOPS feature for eMMC

Enable eMMC background operations (BKOPS) feature.

If URGENT_BKOPS is set after a response, note that BKOPS are required.
Immediately run BKOPS if required.  Read/write operations should be
requested during BKOPS(LEVEL-1), then issue HPI to interrupt the
ongoing BKOPS and service the foreground operation.
(This patch only controls the LEVEL2/3.)

When repeating the writing 1GB data, at a certain time, performance is
decreased.  At that time, card triggers the Level-3 or Level-2.  After
running bkops, performance is recovered.

Future considerations:
 * Check BKOPS_LEVEL=1 and start BKOPS in a preventive manner.
 * Interrupt ongoing BKOPS before powering off the card.
 * How do we get BKOPS_STATUS value (periodically send ext_csd command)?
 * If using periodic bkops, also consider runtime_pm control.

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>
Reviewed-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
(cherry picked from commit 6807769f7bf68984a5aeda4b9b521f1167cbaf00)

Change-Id: Ie01267b7aa7c5ee2e03bb3b1729e6ef47c552cc4
[merez@codeaurora.org: core.c: release_host when stopping BKOPs for
non SDIO cards in suspend]
Signed-off-by: Maya Erez <merez@codeaurora.org>
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index ce4d3c2..87cdba8 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 */
 
@@ -286,6 +287,8 @@
 #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_BOOT_WP			173	/* R/W */
@@ -319,6 +322,7 @@
 #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 */
@@ -326,6 +330,7 @@
 #define EXT_CSD_DATA_TAG_SUPPORT	499	/* RO */
 #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 */
 
 /*
@@ -397,12 +402,23 @@
 
 #define EXT_CSD_PACKED_EVENT_EN	(1 << 3)
 
-#define EXT_CSD_PACKED_FAILURE	(1 << 3)
-
 #define EXT_CSD_PACKED_GENERIC_ERROR	(1 << 0)
 #define EXT_CSD_PACKED_INDEXED_ERROR	(1 << 1)
 
 /*
+ * EXCEPTION_EVENT_STATUS field
+ */
+#define EXT_CSD_URGENT_BKOPS		BIT(0)
+#define EXT_CSD_DYNCAP_NEEDED		BIT(1)
+#define EXT_CSD_SYSPOOL_EXHAUSTED	BIT(2)
+#define EXT_CSD_PACKED_FAILURE		BIT(3)
+
+/*
+ * BKOPS status level
+ */
+#define EXT_CSD_BKOPS_LEVEL_2		0x2
+
+/*
  * MMC_SWITCH access modes
  */