[PATCH] mmc: block: use block layer pm helpers for pm of card device

[PATCH] mmc: block: use block layer pm helpers for pm of card device

[Konstantin Dorfman]

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>From a429c2c9357c26862a45fd01fff3ed7ec5d69fd7 Mon Sep 17 00:00:00 2001
From: Konstantin Dorfman <kdorfman@codeaurora.org>
Date: Wed, 25 Mar 2015 14:43:01 +0200
Subject: [PATCH] mmc: block: use block layer pm helpers for pm of card device

Use of block layer runtime PM helpers, implementing the block layer's
request-based mechanism, simplifies data path of mmc core layer. It
enables to remove synchronous call pm_runtime_get_sync() from mmc core
data path.

The idea and API is designed by Alan Stern and described here:
    http://marc.info/?l=linux-scsi&m=133727953625963&w=2

Signed-off-by: Konstantin Dorfman <kdorfman@codeaurora.org>
---
 drivers/mmc/card/block.c |  4 ++--
 drivers/mmc/card/queue.c |  5 +++++
 drivers/mmc/core/mmc.c   | 13 ++++++++++++-
 include/linux/mmc/card.h |  1 +
 4 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 1fa4c80..de5f85d 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -2017,7 +2017,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 
 	if (req && !mq->mqrq_prev->req)
 		/* claim host only for the first request */
-		mmc_get_card(card);
+		mmc_claim_host(card->host);
 
 	ret = mmc_blk_part_switch(card, md);
 	if (ret) {
@@ -2060,7 +2060,7 @@ out:
 		 * In case sepecial request, there is no reentry to
 		 * the 'mmc_blk_issue_rq' with 'mqrq_prev->req'.
 		 */
-		mmc_put_card(card);
+		mmc_release_host(card->host);
 	return ret;
 }
 
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index feea926..e12c828 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -213,6 +213,11 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
 	if (mmc_can_erase(card))
 		mmc_queue_setup_discard(mq->queue, card);
 
+	if (!subname) {
+		blk_pm_runtime_init(mq->queue, &card->dev);
+		card->q = mq->queue;
+	}
+
 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 	if (host->max_segs == 1) {
 		unsigned int bouncesz;
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index a301a78..bf3f919 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/stat.h>
 #include <linux/pm_runtime.h>
+#include <linux/blkdev.h>
 
 #include <linux/mmc/host.h>
 #include <linux/mmc/card.h>
@@ -1814,11 +1815,17 @@ static int mmc_runtime_suspend(struct mmc_host *host)
 	if (!(host->caps & MMC_CAP_AGGRESSIVE_PM))
 		return 0;
 
+	err = blk_pre_runtime_suspend(host->card->q);
+	if (err)
+		return err;
+
 	err = _mmc_suspend(host, true);
 	if (err)
 		pr_err("%s: error %d doing aggessive suspend\n",
 			mmc_hostname(host), err);
 
+	blk_post_runtime_suspend(host->card->q, err);
+
 	return err;
 }
 
@@ -1832,12 +1839,16 @@ static int mmc_runtime_resume(struct mmc_host *host)
 	if (!(host->caps & (MMC_CAP_AGGRESSIVE_PM | MMC_CAP_RUNTIME_RESUME)))
 		return 0;
 
+	blk_pre_runtime_resume(host->card->q);
+
 	err = _mmc_resume(host);
 	if (err)
 		pr_err("%s: error %d doing aggessive resume\n",
 			mmc_hostname(host), err);
 
-	return 0;
+	blk_post_runtime_resume(host->card->q, err);
+
+	return err;
 }
 
 static int mmc_power_restore(struct mmc_host *host)
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index b0692d2..1f4810b 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -244,6 +244,7 @@ struct mmc_part {
 struct mmc_card {
 	struct mmc_host		*host;		/* the host this device belongs to */
 	struct device		dev;		/* the device */
+	struct request_queue    *q;
 	u32			ocr;		/* the current OCR setting */
 	unsigned int		rca;		/* relative card address of device */
 	unsigned int		type;		/* card type */
-- 
1.8.5.2
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Re: [PATCH] mmc: block: use block layer pm helpers for pm of card device

[Konstantin Dorfman]

Hello all,

Any comments?

I'm working on power management for eMMC CQ command queuing solution 
(these are patches released by Asutosh Das).

Using the block layer pm helpers is important to be able to issue a data 
requests in non-blocking way directly from the block layer contexts, so 
it is important to get feedback about the patch.

Thanks,
Kostya

-- 
Qualcomm Israel, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project