From 4f4670678426135458fb5d80c8de71afb0cee2b9 Mon Sep 17 00:00:00 2001
From: San Mehat <san@google.com>
Date: Thu, 30 Jul 2009 08:21:19 -0700
Subject: [PATCH] mmc: mmcblk: Add support for deferred SD bus resume

Signed-off-by: San Mehat <san@google.com>

mmc: card: Add MMC_BLOCK_DEFERRED_RESUME option to Kconfig

Signed-off-by: San Mehat <san@google.com>
---
 drivers/mmc/card/Kconfig |  9 +++++++++
 drivers/mmc/card/block.c | 16 ++++++++++++++++
 drivers/mmc/core/core.c  |  6 ++++++
 3 files changed, 31 insertions(+)

diff --git a/drivers/mmc/card/Kconfig b/drivers/mmc/card/Kconfig
index 5562308699bc..79d82124413f 100644
--- a/drivers/mmc/card/Kconfig
+++ b/drivers/mmc/card/Kconfig
@@ -50,6 +50,15 @@ config MMC_BLOCK_BOUNCE
 
 	  If unsure, say Y here.
 
+config MMC_BLOCK_DEFERRED_RESUME
+	bool "Deferr MMC layer resume until I/O is requested"
+	depends on MMC_BLOCK
+	default n
+	help
+	  Say Y here to enable deferred MMC resume until I/O
+	  is requested. This will reduce overall resume latency and
+	  save power when theres an SD card inserted but not being used.
+
 config SDIO_UART
 	tristate "SDIO UART/GPS class support"
 	depends on TTY
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 5bec76dd35bd..835d2100bcc8 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -1948,6 +1948,9 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
 	return 0;
 }
 
+static int
+mmc_blk_set_blksize(struct mmc_blk_data *md, struct mmc_card *card);
+
 static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 {
 	int ret;
@@ -1957,6 +1960,13 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 	unsigned long flags;
 	unsigned int cmd_flags = req ? req->cmd_flags : 0;
 
+#ifdef CONFIG_MMC_BLOCK_DEFERRED_RESUME
+	if (mmc_bus_needs_resume(card->host)) {
+		mmc_resume_bus(card->host);
+		mmc_blk_set_blksize(md, card);
+	}
+#endif
+
 	if (req && !mq->mqrq_prev->req)
 		/* claim host only for the first request */
 		mmc_get_card(card);
@@ -2396,6 +2406,9 @@ static int mmc_blk_probe(struct mmc_card *card)
 	mmc_set_drvdata(card, md);
 	mmc_fixup_device(card, blk_fixups);
 
+#ifdef CONFIG_MMC_BLOCK_DEFERRED_RESUME
+	mmc_set_bus_resume_policy(card->host, 1);
+#endif
 	if (mmc_add_disk(md))
 		goto out;
 
@@ -2438,6 +2451,9 @@ static void mmc_blk_remove(struct mmc_card *card)
 	pm_runtime_put_noidle(&card->dev);
 	mmc_blk_remove_req(md);
 	mmc_set_drvdata(card, NULL);
+#ifdef CONFIG_MMC_BLOCK_DEFERRED_RESUME
+	mmc_set_bus_resume_policy(card->host, 0);
+#endif
 }
 
 static int _mmc_blk_suspend(struct mmc_card *card)
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index efa7be8f6453..e02d9bb10125 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2445,6 +2445,12 @@ void mmc_rescan(struct work_struct *work)
 
 	host->detect_change = 0;
 
+	/* If the card was removed the bus will be marked
+	 * as dead - extend the wakelock so userspace
+	 * can respond */
+	if (host->bus_dead)
+		extend_wakelock = 1;
+
 	/*
 	 * Let mmc_bus_put() free the bus/bus_ops if we've found that
 	 * the card is no longer present.