[PATCH 2/2] mmc: sh_mmcif: use PM QoS instead of delayed clock gating for PM

[Guennadi Liakhovetski <g.liakhovetski@xxxxxx>]

Using delayed clock gating to prevent too frequent gating of the clock
is simple and efficient, but too inflexible. We use PM QoS instead to
let the runtime PM subsystem decide, which power states can be entered
at any specific time, depending on the currently active governor.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
---
 drivers/mmc/host/sh_mmcif.c |   27 ++++++++++++++++++++++++---
 1 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
index 497e6f4..5a922be 100644
--- a/drivers/mmc/host/sh_mmcif.c
+++ b/drivers/mmc/host/sh_mmcif.c
@@ -55,6 +55,7 @@
 #include <linux/mmc/sh_mmcif.h>
 #include <linux/pagemap.h>
 #include <linux/platform_device.h>
+#include <linux/pm_qos.h>
 #include <linux/pm_runtime.h>
 #include <linux/spinlock.h>
 #include <linux/module.h>
@@ -226,6 +227,7 @@ struct sh_mmcif_host {
 	size_t blocksize;
 	int sg_idx;
 	int sg_blkidx;
+	struct dev_pm_qos_request pm_qos;
 	bool power;
 	bool card_present;
 
@@ -977,10 +979,26 @@ static int sh_mmcif_get_cd(struct mmc_host *mmc)
 		return p->get_cd(host->pd);
 }
 
+static int sh_mmcif_enable(struct mmc_host *mmc)
+{
+	struct sh_mmcif_host *host = mmc_priv(mmc);
+	dev_pm_qos_add_request(mmc->parent, &host->pm_qos, 100);
+	return 0;
+}
+
+static int sh_mmcif_disable(struct mmc_host *mmc, int lazy)
+{
+	struct sh_mmcif_host *host = mmc_priv(mmc);
+	dev_pm_qos_remove_request(&host->pm_qos);
+	return 0;
+}
+
 static struct mmc_host_ops sh_mmcif_ops = {
 	.request	= sh_mmcif_request,
 	.set_ios	= sh_mmcif_set_ios,
 	.get_cd		= sh_mmcif_get_cd,
+	.enable		= sh_mmcif_enable,
+	.disable	= sh_mmcif_disable,
 };
 
 static bool sh_mmcif_end_cmd(struct sh_mmcif_host *host)
@@ -1061,7 +1079,6 @@ static irqreturn_t sh_mmcif_irqt(int irq, void *dev_id)
 {
 	struct sh_mmcif_host *host = dev_id;
 	struct mmc_request *mrq = host->mrq;
-	struct mmc_data *data = mrq->data;
 
 	cancel_delayed_work_sync(&host->timeout_work);
 
@@ -1109,13 +1126,15 @@ static irqreturn_t sh_mmcif_irqt(int irq, void *dev_id)
 	case MMCIF_WAIT_FOR_READ_END:
 	case MMCIF_WAIT_FOR_WRITE_END:
 		if (host->sd_error)
-			data->error = sh_mmcif_error_manage(host);
+			mrq->data->error = sh_mmcif_error_manage(host);
 		break;
 	default:
 		BUG();
 	}
 
 	if (host->wait_for != MMCIF_WAIT_FOR_STOP) {
+		struct mmc_data *data = mrq->data;
+
 		if (!mrq->cmd->error && data && !data->error)
 			data->bytes_xfered =
 				data->blocks * data->blksz;
@@ -1303,12 +1322,14 @@ static int __devinit sh_mmcif_probe(struct platform_device *pdev)
 		mmc->f_min = mmc->f_max / 512;
 	if (pd->ocr)
 		mmc->ocr_avail = pd->ocr;
-	mmc->caps = MMC_CAP_MMC_HIGHSPEED | pd->caps;
+	mmc->caps = MMC_CAP_MMC_HIGHSPEED | MMC_CAP_DISABLE | pd->caps;
 	mmc->max_segs = 32;
 	mmc->max_blk_size = 512;
 	mmc->max_req_size = PAGE_CACHE_SIZE * mmc->max_segs;
 	mmc->max_blk_count = mmc->max_req_size / mmc->max_blk_size;
 	mmc->max_seg_size = mmc->max_req_size;
+	/* disable delayed clock gating, we use PM QoS for precise PM */
+	mmc->clkgate_delay = 0;
 
 	sh_mmcif_sync_reset(host);
 	platform_set_drvdata(pdev, host);
-- 
1.7.2.5

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