[RFC/PATCH 1/1] mmc: block: Add MMC write packing statistics

[Maya Erez <merez@codeaurora.org>]

The write packing statistics are used for the packed commands unit tests
in order to determine test success or failure

Signed-off-by: Maya Erez <merez@codeaurora.org>

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 2785fd4..c33c0c8 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -63,6 +63,11 @@ MODULE_ALIAS("mmc:block");
 			(rq_data_dir(req) == WRITE))
 #define PACKED_CMD_VER		0x01
 #define PACKED_CMD_WR		0x02
+#define MMC_BLK_UPDATE_STOP_REASON(stats, reason)			\
+	do {								\
+		if (stats->enabled)					\
+			stats->pack_stop_reason[reason]++;		\
+	} while (0)

 static DEFINE_MUTEX(block_mutex);

@@ -1313,6 +1318,35 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
 	mmc_queue_bounce_pre(mqrq);
 }

+struct mmc_wr_pack_stats *mmc_blk_get_packed_statistics(struct mmc_card *card)
+{
+	if (!card)
+		return NULL;
+
+	return &card->wr_pack_stats;
+}
+EXPORT_SYMBOL(mmc_blk_get_packed_statistics);
+
+void mmc_blk_init_packed_statistics(struct mmc_card *card)
+{
+	int max_num_of_packed_reqs = 0;
+
+	if (!card || !card->wr_pack_stats.packing_events)
+		return;
+
+	max_num_of_packed_reqs = card->ext_csd.max_packed_writes;
+
+	spin_lock(&card->wr_pack_stats.lock);
+	memset(card->wr_pack_stats.packing_events, 0,
+		(max_num_of_packed_reqs + 1) *
+	       sizeof(*card->wr_pack_stats.packing_events));
+	memset(&card->wr_pack_stats.pack_stop_reason, 0,
+		sizeof(card->wr_pack_stats.pack_stop_reason));
+	card->wr_pack_stats.enabled = true;
+	spin_unlock(&card->wr_pack_stats.lock);
+}
+EXPORT_SYMBOL(mmc_blk_init_packed_statistics);
+
 static u8 mmc_blk_prep_packed_list(struct mmc_queue *mq, struct request *req)
 {
 	struct request_queue *q = mq->queue;
@@ -1325,6 +1359,7 @@ static u8 mmc_blk_prep_packed_list(struct mmc_queue *mq, struct request *req)
 	u8 put_back = 0;
 	u8 max_packed_rw = 0;
 	u8 reqs = 0;
+	struct mmc_wr_pack_stats *stats = &card->wr_pack_stats;

 	mmc_blk_clear_packed(mq->mqrq_cur);

@@ -1359,20 +1394,26 @@ static u8 mmc_blk_prep_packed_list(struct mmc_queue *mq, struct request *req)
 		phys_segments++;
 	}

+	spin_lock(&stats->lock);
+
 	while (reqs < max_packed_rw - 1) {
 		spin_lock_irq(q->queue_lock);
 		next = blk_fetch_request(q);
 		spin_unlock_irq(q->queue_lock);
-		if (!next)
+		if (!next) {
+			MMC_BLK_UPDATE_STOP_REASON(stats, EMPTY_QUEUE);
 			break;
+		}

 		if (next->cmd_flags & REQ_DISCARD ||
 				next->cmd_flags & REQ_FLUSH) {
+			MMC_BLK_UPDATE_STOP_REASON(stats, FLUSH_OR_DISCARD);
 			put_back = 1;
 			break;
 		}

 		if (rq_data_dir(cur) != rq_data_dir(next)) {
+			MMC_BLK_UPDATE_STOP_REASON(stats, WRONG_DATA_DIR);
 			put_back = 1;
 			break;
 		}
@@ -1380,18 +1421,22 @@ static u8 mmc_blk_prep_packed_list(struct mmc_queue *mq, struct request *req)
 		if (mmc_req_rel_wr(next) &&
 				(md->flags & MMC_BLK_REL_WR) &&
 				!en_rel_wr) {
+			MMC_BLK_UPDATE_STOP_REASON(stats, REL_WRITE);
 			put_back = 1;
 			break;
 		}

 		req_sectors += blk_rq_sectors(next);
 		if (req_sectors > max_blk_count) {
+			if (stats->enabled)
+				stats->pack_stop_reason[EXCEEDS_SECTORS]++;
 			put_back = 1;
 			break;
 		}

 		phys_segments +=  next->nr_phys_segments;
 		if (phys_segments > max_phys_segs) {
+			MMC_BLK_UPDATE_STOP_REASON(stats, EXCEEDS_SEGMENTS);
 			put_back = 1;
 			break;
 		}
@@ -1407,6 +1452,15 @@ static u8 mmc_blk_prep_packed_list(struct mmc_queue *mq, struct request *req)
 		spin_unlock_irq(q->queue_lock);
 	}

+	if (stats->enabled) {
+		if (reqs + 1 <= card->ext_csd.max_packed_writes)
+			stats->packing_events[reqs + 1]++;
+		if (reqs + 1 == max_packed_rw)
+			MMC_BLK_UPDATE_STOP_REASON(stats, THRESHOLD);
+	}
+
+	spin_unlock(&stats->lock);
+
 	if (reqs > 0) {
 		list_add(&req->queuelist, &mq->mqrq_cur->packed_list);
 		mq->mqrq_cur->packed_num = ++reqs;
diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
index 9b68933..e3b0e74 100644
--- a/drivers/mmc/core/bus.c
+++ b/drivers/mmc/core/bus.c
@@ -251,6 +251,8 @@ struct mmc_card *mmc_alloc_card(struct mmc_host *host, struct device_type *type)
 	card->dev.release = mmc_release_card;
 	card->dev.type = type;

+	spin_lock_init(&card->wr_pack_stats.lock);
+
 	return card;
 }

@@ -353,6 +355,8 @@ void mmc_remove_card(struct mmc_card *card)
 		device_del(&card->dev);
 	}

+	kfree(card->wr_pack_stats.packing_events);
+
 	put_device(&card->dev);
 }

diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index 9ab5b17..898e358 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -318,6 +318,164 @@ static const struct file_operations mmc_dbg_ext_csd_fops = {
 	.llseek		= default_llseek,
 };

+static int mmc_wr_pack_stats_open(struct inode *inode, struct file *filp)
+{
+	struct mmc_card *card = inode->i_private;
+
+	filp->private_data = card;
+	card->wr_pack_stats.print_in_read = 1;
+	return 0;
+}
+
+#define TEMP_BUF_SIZE 256
+static ssize_t mmc_wr_pack_stats_read(struct file *filp, char __user *ubuf,
+				size_t cnt, loff_t *ppos)
+{
+	struct mmc_card *card = filp->private_data;
+	struct mmc_wr_pack_stats *pack_stats;
+	int i;
+	int max_num_of_packed_reqs = 0;
+	char *temp_buf;
+
+	if (!card)
+		return cnt;
+
+	if (!card->wr_pack_stats.print_in_read)
+		return 0;
+
+	if (!card->wr_pack_stats.enabled) {
+		pr_info("%s: write packing statistics are disabled\n",
+			 mmc_hostname(card->host));
+		goto exit;
+	}
+
+	pack_stats = &card->wr_pack_stats;
+
+	if (!pack_stats->packing_events) {
+		pr_info("%s: NULL packing_events\n", mmc_hostname(card->host));
+		goto exit;
+	}
+
+	max_num_of_packed_reqs = card->ext_csd.max_packed_writes;
+
+	temp_buf = kmalloc(TEMP_BUF_SIZE, GFP_KERNEL);
+	if (!temp_buf)
+		goto exit;
+
+	spin_lock(&pack_stats->lock);
+
+	snprintf(temp_buf, TEMP_BUF_SIZE, "%s: write packing statistics:\n",
+		mmc_hostname(card->host));
+	strlcat(ubuf, temp_buf, cnt);
+
+	for (i = 1 ; i <= max_num_of_packed_reqs ; ++i) {
+		if (pack_stats->packing_events[i]) {
+			snprintf(temp_buf, TEMP_BUF_SIZE,
+				 "%s: Packed %d reqs - %d times\n",
+				mmc_hostname(card->host), i,
+				pack_stats->packing_events[i]);
+			strlcat(ubuf, temp_buf, cnt);
+		}
+	}
+
+	snprintf(temp_buf, TEMP_BUF_SIZE,
+		 "%s: stopped packing due to the following reasons:\n",
+		 mmc_hostname(card->host));
+	strlcat(ubuf, temp_buf, cnt);
+
+	if (pack_stats->pack_stop_reason[EXCEEDS_SEGMENTS]) {
+		snprintf(temp_buf, TEMP_BUF_SIZE,
+			 "%s: %d times: exceed max num of segments\n",
+			 mmc_hostname(card->host),
+			 pack_stats->pack_stop_reason[EXCEEDS_SEGMENTS]);
+		strlcat(ubuf, temp_buf, cnt);
+	}
+	if (pack_stats->pack_stop_reason[EXCEEDS_SECTORS]) {
+		snprintf(temp_buf, TEMP_BUF_SIZE,
+			 "%s: %d times: exceed max num of sectors\n",
+			mmc_hostname(card->host),
+			pack_stats->pack_stop_reason[EXCEEDS_SECTORS]);
+		strlcat(ubuf, temp_buf, cnt);
+	}
+	if (pack_stats->pack_stop_reason[WRONG_DATA_DIR]) {
+		snprintf(temp_buf, TEMP_BUF_SIZE,
+			 "%s: %d times: wrong data direction\n",
+			mmc_hostname(card->host),
+			pack_stats->pack_stop_reason[WRONG_DATA_DIR]);
+		strlcat(ubuf, temp_buf, cnt);
+	}
+	if (pack_stats->pack_stop_reason[FLUSH_OR_DISCARD]) {
+		snprintf(temp_buf, TEMP_BUF_SIZE,
+			 "%s: %d times: flush or discard\n",
+			mmc_hostname(card->host),
+			pack_stats->pack_stop_reason[FLUSH_OR_DISCARD]);
+		strlcat(ubuf, temp_buf, cnt);
+	}
+	if (pack_stats->pack_stop_reason[EMPTY_QUEUE]) {
+		snprintf(temp_buf, TEMP_BUF_SIZE,
+			 "%s: %d times: empty queue\n",
+			mmc_hostname(card->host),
+			pack_stats->pack_stop_reason[EMPTY_QUEUE]);
+		strlcat(ubuf, temp_buf, cnt);
+	}
+	if (pack_stats->pack_stop_reason[REL_WRITE]) {
+		snprintf(temp_buf, TEMP_BUF_SIZE,
+			 "%s: %d times: rel write\n",
+			mmc_hostname(card->host),
+			pack_stats->pack_stop_reason[REL_WRITE]);
+		strlcat(ubuf, temp_buf, cnt);
+	}
+	if (pack_stats->pack_stop_reason[THRESHOLD]) {
+		snprintf(temp_buf, TEMP_BUF_SIZE,
+			 "%s: %d times: Threshold\n",
+			mmc_hostname(card->host),
+			pack_stats->pack_stop_reason[THRESHOLD]);
+		strlcat(ubuf, temp_buf, cnt);
+	}
+
+	spin_unlock(&pack_stats->lock);
+
+	kfree(temp_buf);
+
+	pr_info("%s", ubuf);
+
+exit:
+	if (card->wr_pack_stats.print_in_read == 1) {
+		card->wr_pack_stats.print_in_read = 0;
+		return strnlen(ubuf, cnt);
+	}
+
+	return 0;
+}
+
+static ssize_t mmc_wr_pack_stats_write(struct file *filp,
+				       const char __user *ubuf, size_t cnt,
+				       loff_t *ppos)
+{
+	struct mmc_card *card = filp->private_data;
+	int value;
+
+	if (!card)
+		return cnt;
+
+	sscanf(ubuf, "%d", &value);
+	if (value) {
+		mmc_blk_init_packed_statistics(card);
+	} else {
+		spin_lock(&card->wr_pack_stats.lock);
+		card->wr_pack_stats.enabled = false;
+		spin_unlock(&card->wr_pack_stats.lock);
+	}
+
+	return cnt;
+}
+
+static const struct file_operations mmc_dbg_wr_pack_stats_fops = {
+	.open		= mmc_wr_pack_stats_open,
+	.read		= mmc_wr_pack_stats_read,
+	.write		= mmc_wr_pack_stats_write,
+};
+
 void mmc_add_card_debugfs(struct mmc_card *card)
 {
 	struct mmc_host	*host = card->host;
@@ -350,6 +508,12 @@ void mmc_add_card_debugfs(struct mmc_card *card)
 					&mmc_dbg_ext_csd_fops))
 			goto err;

+	if (mmc_card_mmc(card) && (card->ext_csd.rev >= 6) &&
+	    (card->host->caps2 & MMC_CAP2_PACKED_WR))
+		if (!debugfs_create_file("wr_pack_stats", S_IRUSR, root, card,
+					 &mmc_dbg_wr_pack_stats_fops))
+			goto err;
+
 	return;

 err:
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 9b421fb..6b0b85d 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1268,6 +1268,24 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 		} else {
 			card->ext_csd.packed_event_en = 1;
 		}
+
+	}
+
+	if (!oldcard) {
+		if ((host->caps2 & MMC_CAP2_PACKED_CMD) &&
+		    (card->ext_csd.max_packed_writes > 0)) {
+			/*
+			 * We would like to keep the statistics in an index
+			 * that equals the num of packed requests
+			 * (1 to max_packed_writes)
+			 */
+			card->wr_pack_stats.packing_events = kzalloc(
+				(card->ext_csd.max_packed_writes + 1) *
+				sizeof(*card->wr_pack_stats.packing_events),
+				GFP_KERNEL);
+			if (!card->wr_pack_stats.packing_events)
+				goto free_card;
+		}
 	}

 	if (!oldcard)
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 4aeb4e9..d3ffef6 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -205,6 +205,25 @@ struct mmc_part {
 #define MMC_BLK_DATA_AREA_GP	(1<<2)
 };

+enum mmc_packed_stop_reasons {
+	EXCEEDS_SEGMENTS = 0,
+	EXCEEDS_SECTORS,
+	WRONG_DATA_DIR,
+	FLUSH_OR_DISCARD,
+	EMPTY_QUEUE,
+	REL_WRITE,
+	THRESHOLD,
+	MAX_REASONS,
+};
+
+struct mmc_wr_pack_stats {
+	u32 *packing_events;
+	u32 pack_stop_reason[MAX_REASONS];
+	spinlock_t lock;
+	bool enabled;
+	bool print_in_read;
+};
+
 /*
  * MMC device
  */
@@ -277,6 +296,7 @@ struct mmc_card {
 	struct dentry		*debugfs_root;
 	struct mmc_part	part[MMC_NUM_PHY_PARTITION]; /* physical partitions */
 	unsigned int    nr_parts;
+	struct mmc_wr_pack_stats wr_pack_stats; /* packed commands stats*/
 };

 /*
@@ -498,4 +518,8 @@ extern void mmc_unregister_driver(struct mmc_driver *);
 extern void mmc_fixup_device(struct mmc_card *card,
 			     const struct mmc_fixup *table);

+extern struct mmc_wr_pack_stats *mmc_blk_get_packed_statistics(
+			struct mmc_card *card);
+extern void mmc_blk_init_packed_statistics(struct mmc_card *card);
+
 #endif /* LINUX_MMC_CARD_H */
--
1.7.3.3
-- 
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.