mmc: add packed command feature of eMMC4.5

This patch adds packed command feature of eMMC4.5.  The maximum number
for packing read (or write) is offered and exception event relevant to
packed command which is used for error handling is enabled. If host
wants to use this feature, MMC_CAP2_PACKED_CMD should be set.

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Reviewed-by: Maya Erez <merez@codeaurora.org>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/core/mmc.c

@@ -538,6 +538,11 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
 		} else {
 			card->ext_csd.data_tag_unit_size = 0;
 		}
+
+		card->ext_csd.max_packed_writes =
+			ext_csd[EXT_CSD_MAX_PACKED_WRITES];
+		card->ext_csd.max_packed_reads =
+			ext_csd[EXT_CSD_MAX_PACKED_READS];
 	} else {
 		card->ext_csd.data_sector_size = 512;
 	}
@@ -1275,6 +1280,29 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 		}
 	}
 
+	/*
+	 * The mandatory minimum values are defined for packed command.
+	 * read: 5, write: 3
+	 */
+	if (card->ext_csd.max_packed_writes >= 3 &&
+	    card->ext_csd.max_packed_reads >= 5 &&
+	    host->caps2 & MMC_CAP2_PACKED_CMD) {
+		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+				EXT_CSD_EXP_EVENTS_CTRL,
+				EXT_CSD_PACKED_EVENT_EN,
+				card->ext_csd.generic_cmd6_time);
+		if (err && err != -EBADMSG)
+			goto free_card;
+		if (err) {
+			pr_warn("%s: Enabling packed event failed\n",
+				mmc_hostname(card->host));
+			card->ext_csd.packed_event_en = 0;
+			err = 0;
+		} else {
+			card->ext_csd.packed_event_en = 1;
+		}
+	}
+
 	if (!oldcard)
 		host->card = card;
 

include/linux/mmc/card.h

@@ -53,6 +53,9 @@ struct mmc_ext_csd {
 	u8			part_config;
 	u8			cache_ctrl;
 	u8			rst_n_function;
+	u8			max_packed_writes;
+	u8			max_packed_reads;
+	u8			packed_event_en;
 	unsigned int		part_time;		/* Units: ms */
 	unsigned int		sa_timeout;		/* Units: 100ns */
 	unsigned int		generic_cmd6_time;	/* Units: 10ms */

include/linux/mmc/host.h

@@ -276,6 +276,10 @@ struct mmc_host {
 #define MMC_CAP2_HC_ERASE_SZ	(1 << 9)	/* High-capacity erase size */
 #define MMC_CAP2_CD_ACTIVE_HIGH	(1 << 10)	/* Card-detect signal active high */
 #define MMC_CAP2_RO_ACTIVE_HIGH	(1 << 11)	/* Write-protect signal active high */
+#define MMC_CAP2_PACKED_RD	(1 << 12)	/* Allow packed read */
+#define MMC_CAP2_PACKED_WR	(1 << 13)	/* Allow packed write */
+#define MMC_CAP2_PACKED_CMD	(MMC_CAP2_PACKED_RD | \
+				 MMC_CAP2_PACKED_WR)
 
 	mmc_pm_flag_t		pm_caps;	/* supported pm features */
 

include/linux/mmc/mmc.h

@@ -139,7 +139,7 @@ static inline bool mmc_op_multi(u32 opcode)
 #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_EXCEPTION_EVENT	(1 << 6)	/* sr, a */
 #define R1_APP_CMD		(1 << 5)	/* sr, c */
 
 #define R1_STATE_IDLE	0
@@ -275,7 +275,10 @@ struct _mmc_csd {
 #define EXT_CSD_FLUSH_CACHE		32      /* W */
 #define EXT_CSD_CACHE_CTRL		33      /* R/W */
 #define EXT_CSD_POWER_OFF_NOTIFICATION	34	/* R/W */
-#define EXT_CSD_EXP_EVENTS_STATUS	54	/* RO */
+#define EXT_CSD_PACKED_FAILURE_INDEX	35	/* RO */
+#define EXT_CSD_PACKED_CMD_STATUS	36	/* RO */
+#define EXT_CSD_EXP_EVENTS_STATUS	54	/* RO, 2 bytes */
+#define EXT_CSD_EXP_EVENTS_CTRL		56	/* R/W, 2 bytes */
 #define EXT_CSD_DATA_SECTOR_SIZE	61	/* R */
 #define EXT_CSD_GP_SIZE_MULT		143	/* R/W */
 #define EXT_CSD_PARTITION_ATTRIBUTE	156	/* R/W */
@@ -324,6 +327,8 @@ struct _mmc_csd {
 #define EXT_CSD_CACHE_SIZE		249	/* RO, 4 bytes */
 #define EXT_CSD_TAG_UNIT_SIZE		498	/* RO */
 #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 */
 
@@ -385,6 +390,9 @@ struct _mmc_csd {
 #define EXT_CSD_PWR_CL_4BIT_MASK	0x0F	/* 8 bit PWR CLS */
 #define EXT_CSD_PWR_CL_8BIT_SHIFT	4
 #define EXT_CSD_PWR_CL_4BIT_SHIFT	0
+
+#define EXT_CSD_PACKED_EVENT_EN	BIT(3)
+
 /*
  * EXCEPTION_EVENT_STATUS field
  */
@@ -393,6 +401,9 @@ struct _mmc_csd {
 #define EXT_CSD_SYSPOOL_EXHAUSTED	BIT(2)
 #define EXT_CSD_PACKED_FAILURE		BIT(3)
 
+#define EXT_CSD_PACKED_GENERIC_ERROR	BIT(0)
+#define EXT_CSD_PACKED_INDEXED_ERROR	BIT(1)
+
 /*
  * BKOPS status level
  */