[RFC PATCH] mmc: support background operation

[Jaehoon Chung <jh80.chung@samsung.com>]

Hi mailing.

This RFC patch is supported background operation(BKOPS).
And if you want to test this patch, must apply "[PATCH v3] mmc: support HPI send command"

This patch is based on Hanumath Prasad's patch "mmc: enable background operations for emmc4.41 with HPI support"
Hanumath's patch is implemented before applied per forlin's patch "use nonblock mmc request...".
This patch is based on 3.1.0-rc1 in mmc-next.

Background operations is run when set the URGENT_BKOPS in response.

if set the URGENT_BKOPS in response, we can notify that card need the BKOPS.
(URGENT_BKOPS is used in eMMC4.41 spec, but in eMMC4.5 changed to EXCEPTION_EVENT bit.
 maybe, we need to change this point).

And all request is done, then run background operation.
if request read/write operation when running BKOPS, issue HPI interrupt

This patch is just RFC patch (not to merge), because i want to use BKOPS in userspace.
(using ioctl).

I want to get mailing's review for this patch.


Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Hanumath Prasad <hanumath.prasad@stericsson.com>

---
 drivers/mmc/card/block.c   |    4 ++++
 drivers/mmc/card/queue.c   |   10 ++++++++++
 drivers/mmc/core/core.c    |   35 +++++++++++++++++++++++++++++++++++
 drivers/mmc/core/mmc.c     |   28 ++++++++++++++++++++++++++++
 drivers/mmc/core/mmc_ops.c |    3 +++
 include/linux/mmc/card.h   |   11 +++++++++++
 include/linux/mmc/core.h   |    1 +
 include/linux/mmc/mmc.h    |    4 ++++
 8 files changed, 96 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 1ff5486..ff72c4a 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -1078,6 +1078,10 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
 		switch (status) {
 		case MMC_BLK_SUCCESS:
 		case MMC_BLK_PARTIAL:
+			if (mmc_card_mmc(card) &&
+				(brq->cmd.resp[0] & R1_URGENT_BKOPS)) {
+				mmc_card_set_need_bkops(card);
+			}
 			/*
 			 * A block was successfully transferred.
 			 */
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index 45fb362..52b1293 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -46,6 +46,8 @@ static int mmc_queue_thread(void *d)
 {
 	struct mmc_queue *mq = d;
 	struct request_queue *q = mq->queue;
+	struct mmc_card *card = mq->card;
+	unsigned long flags;
 
 	current->flags |= PF_MEMALLOC;
 
@@ -61,6 +63,13 @@ static int mmc_queue_thread(void *d)
 		spin_unlock_irq(q->queue_lock);
 
 		if (req || mq->mqrq_prev->req) {
+			if (mmc_card_doing_bkops(card)) {
+				mmc_interrupt_hpi(card);
+				spin_lock_irqsave(&card->host->lock, flags);
+				mmc_card_clr_doing_bkops(card);
+				spin_unlock_irqrestore(&card->host->lock,
+						flags);
+			}
 			set_current_state(TASK_RUNNING);
 			mq->issue_fn(mq, req);
 		} else {
@@ -68,6 +77,7 @@ static int mmc_queue_thread(void *d)
 				set_current_state(TASK_RUNNING);
 				break;
 			}
+			mmc_start_bkops(mq->card);
 			up(&mq->thread_sem);
 			schedule();
 			down(&mq->thread_sem);
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 7c1ab06..b6de0e5 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -347,6 +347,41 @@ int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries
 
 EXPORT_SYMBOL(mmc_wait_for_cmd);
 
+/* Start background operation */
+void mmc_start_bkops(struct mmc_card *card)
+{
+	int err;
+	unsigned long flags;
+
+	BUG_ON(!card);
+
+	if (!card->ext_csd.bkops_en) {
+		printk(KERN_INFO "Didn't set BKOPS enable bit!\n");
+		return;
+	}
+
+	if (mmc_card_doing_bkops(card) ||
+			!mmc_card_need_bkops(card)) {
+		return;
+	}
+
+	mmc_claim_host(card->host);
+	err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+		EXT_CSD_BKOPS_START, 1, 0);
+	if (err) {
+		mmc_card_clr_need_bkops(card);
+		goto out;
+	}
+
+	spin_lock_irqsave(&card->host->lock, flags);
+	mmc_card_clr_need_bkops(card);
+	mmc_card_set_doing_bkops(card);
+	spin_unlock_irqrestore(&card->host->lock, flags);
+out:
+	mmc_release_host(card->host);
+}
+EXPORT_SYMBOL(mmc_start_bkops);
+
 /**
  *	mmc_interrupt_hpi - Issue for High priority Interrupt
  *	@card: the MMC card associated with the HPI transfer
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index ef10bfd..0372414 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -421,6 +421,17 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
 				ext_csd[EXT_CSD_OUT_OF_INTERRUPT_TIME] * 10;
 		}
 
+		/*
+		 * check whether the eMMC card support BKOPS.
+		 * if set BKOPS_SUPPORT bit,
+		 * BKOPS_STATUS, BKOPS_EN,,BKOPS_START and
+		 * URGENT_BKOPS are supported.(default)
+		 */
+		if (ext_csd[EXT_CSD_BKOPS_SUPPORT] & 0x1) {
+			card->ext_csd.bkops = 1;
+			card->ext_csd.bkops_en = ext_csd[EXT_CSD_BKOPS_EN];
+		}
+
 		card->ext_csd.rel_param = ext_csd[EXT_CSD_WR_REL_PARAM];
 	}
 
@@ -762,6 +773,23 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 	}
 
 	/*
+	 * Enable HPI feature (if supported)
+	 */
+	if (card->ext_csd.hpi) {
+		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+			EXT_CSD_HPI_MGMT, 1, 0);
+		if (err && err != -EBADMSG)
+			goto free_card;
+
+		if (err) {
+			printk(KERN_WARNING "%s: Enabling HPI failed\n",
+				mmc_hostname(card->host));
+			err = 0;
+		} else
+			card->ext_csd.hpi_en = 1;
+	}
+
+	/*
 	 * Compute bus speed.
 	 */
 	max_dtr = (unsigned int)-1;
diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 4706400..2a54221 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -398,6 +398,9 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
 	if (err)
 		return err;
 
+	if (index == EXT_CSD_BKOPS_START)
+		return 0;
+
 	/* Must check status to be sure of no errors */
 	do {
 		err = mmc_send_status(card, &status);
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 411054d..137887d 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -67,6 +67,8 @@ struct mmc_ext_csd {
 	bool			hpi_en;			/* HPI enablebit */
 	bool			hpi;			/* HPI support bit */
 	unsigned int		hpi_cmd;		/* cmd used as HPI */
+	bool			bkops;			/* BKOPS support bit */
+	bool			bkops_en;		/* BKOPS enable bit */
 	u8			raw_partition_support;	/* 160 */
 	u8			raw_erased_mem_count;	/* 181 */
 	u8			raw_ext_csd_structure;	/* 194 */
@@ -192,6 +194,8 @@ struct mmc_card {
 #define MMC_QUIRK_DISABLE_CD	(1<<5)		/* disconnect CD/DAT[3] resistor */
 #define MMC_QUIRK_INAND_CMD38	(1<<6)		/* iNAND devices have broken CMD38 */
 #define MMC_QUIRK_BLK_NO_CMD23	(1<<7)		/* Avoid CMD23 for regular multiblock */
+#define MMC_STATE_NEED_BKOPS	(1<<7)		/* Need background operation */
+#define MMC_STATE_DOING_BKOPS	(1<<8)		/* Do running background operation */
 
 	unsigned int		erase_size;	/* erase size in sectors */
  	unsigned int		erase_shift;	/* if erase unit is power 2 */
@@ -318,6 +322,8 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
 #define mmc_card_ddr_mode(c)	((c)->state & MMC_STATE_HIGHSPEED_DDR)
 #define mmc_sd_card_uhs(c) ((c)->state & MMC_STATE_ULTRAHIGHSPEED)
 #define mmc_card_ext_capacity(c) ((c)->state & MMC_CARD_SDXC)
+#define mmc_card_need_bkops(c) ((c)->state & MMC_STATE_NEED_BKOPS)
+#define mmc_card_doing_bkops(c) ((c)->state & MMC_STATE_DOING_BKOPS)
 
 #define mmc_card_set_present(c)	((c)->state |= MMC_STATE_PRESENT)
 #define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)
@@ -326,6 +332,11 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
 #define mmc_card_set_ddr_mode(c) ((c)->state |= MMC_STATE_HIGHSPEED_DDR)
 #define mmc_sd_card_set_uhs(c) ((c)->state |= MMC_STATE_ULTRAHIGHSPEED)
 #define mmc_card_set_ext_capacity(c) ((c)->state |= MMC_CARD_SDXC)
+#define mmc_card_set_need_bkops(c) ((c)->state |= MMC_STATE_NEED_BKOPS)
+#define mmc_card_set_doing_bkops(c) ((c)->state |= MMC_STATE_DOING_BKOPS)
+
+#define mmc_card_clr_need_bkops(c) ((c)->state &= ~MMC_STATE_NEED_BKOPS)
+#define mmc_card_clr_doing_bkops(c) ((c)->state &= ~MMC_STATE_DOING_BKOPS)
 
 /*
  * Quirk add/remove for MMC products.
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index dca3c08..90f2e1c 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -162,6 +162,7 @@ extern int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,
 				   unsigned int nr);
 extern unsigned int mmc_calc_max_discard(struct mmc_card *card);
 
+extern void mmc_start_bkops(struct mmc_card *card);
 extern int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen);
 
 extern void mmc_set_data_timeout(struct mmc_data *, const struct mmc_card *);
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index e16c776..419a48e 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -139,6 +139,7 @@ static inline bool mmc_op_multi(u32 opcode)
 #define R1_READY_FOR_DATA	(1 << 8)	/* sx, a */
 #define R1_SWITCH_ERROR		(1 << 7)	/* sx, c */
 #define R1_APP_CMD		(1 << 5)	/* sr, c */
+#define R1_URGENT_BKOPS		(1 << 6)	/* sr, a */
 
 #define R1_STATE_IDLE	0
 #define R1_STATE_READY	1
@@ -273,6 +274,8 @@ struct _mmc_csd {
 #define EXT_CSD_PARTITION_ATTRIBUTE	156	/* R/W */
 #define EXT_CSD_PARTITION_SUPPORT	160	/* RO */
 #define EXT_CSD_HPI_MGMT		161	/* R/W */
+#define EXT_CSD_BKOPS_EN		163	/* R/W */
+#define EXT_CSD_BKOPS_START		164	/* 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 */
@@ -295,6 +298,7 @@ struct _mmc_csd {
 #define EXT_CSD_SEC_ERASE_MULT		230	/* RO */
 #define EXT_CSD_SEC_FEATURE_SUPPORT	231	/* RO */
 #define EXT_CSD_TRIM_MULT		232	/* RO */
+#define EXT_CSD_BKOPS_SUPPORT		502	/* RO */
 #define EXT_CSD_HPI_FEATURES		503	/* RO */
 
 /*