mmc: tmio: maximize power saving

This patch uses runtime PM to allow the system to power down the MMC
controller, when the MMC closk is switched off.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/tmio_mmc.h

@@ -53,6 +53,8 @@ struct tmio_mmc_host {
 	void (*set_clk_div)(struct platform_device *host, int state);
 
 	int			pm_error;
+	/* recognise system-wide suspend in runtime PM methods */
+	bool			pm_global;
 
 	/* pio related stuff */
 	struct scatterlist      *sg_ptr;

drivers/mmc/host/tmio_mmc_pio.c

@@ -546,6 +546,7 @@ static void tmio_mmc_cmd_irq(struct tmio_mmc_host *host,
 irqreturn_t tmio_mmc_irq(int irq, void *devid)
 {
 	struct tmio_mmc_host *host = devid;
+	struct mmc_host *mmc = host->mmc;
 	struct tmio_mmc_data *pdata = host->pdata;
 	unsigned int ireg, irq_mask, status;
 	unsigned int sdio_ireg, sdio_irq_mask, sdio_status;
@@ -567,13 +568,13 @@ irqreturn_t tmio_mmc_irq(int irq, void *devid)
 		if (sdio_ireg && !host->sdio_irq_enabled) {
 			pr_warning("tmio_mmc: Spurious SDIO IRQ, disabling! 0x%04x 0x%04x 0x%04x\n",
 				   sdio_status, sdio_irq_mask, sdio_ireg);
-			tmio_mmc_enable_sdio_irq(host->mmc, 0);
+			tmio_mmc_enable_sdio_irq(mmc, 0);
 			goto out;
 		}
 
-		if (host->mmc->caps & MMC_CAP_SDIO_IRQ &&
+		if (mmc->caps & MMC_CAP_SDIO_IRQ &&
 			sdio_ireg & TMIO_SDIO_STAT_IOIRQ)
-			mmc_signal_sdio_irq(host->mmc);
+			mmc_signal_sdio_irq(mmc);
 
 		if (sdio_ireg)
 			goto out;
@@ -586,7 +587,9 @@ irqreturn_t tmio_mmc_irq(int irq, void *devid)
 	if (ireg & (TMIO_STAT_CARD_INSERT | TMIO_STAT_CARD_REMOVE)) {
 		tmio_mmc_ack_mmc_irqs(host, TMIO_STAT_CARD_INSERT |
 			TMIO_STAT_CARD_REMOVE);
-		if (!work_pending(&host->mmc->detect.work))
+		if ((((ireg & TMIO_STAT_CARD_REMOVE) && mmc->card) ||
+		     ((ireg & TMIO_STAT_CARD_INSERT) && !mmc->card)) &&
+		    !work_pending(&mmc->detect.work))
 			mmc_detect_change(host->mmc, msecs_to_jiffies(100));
 		goto out;
 	}
@@ -743,21 +746,22 @@ static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 
 	spin_unlock_irqrestore(&host->lock, flags);
 
-	if (ios->clock)
-		tmio_mmc_set_clock(host, ios->clock);
-
-	/* Power sequence - OFF -> UP -> ON */
-	if (ios->power_mode == MMC_POWER_UP) {
-		if ((pdata->flags & TMIO_MMC_HAS_COLD_CD) && !pdata->power) {
+	/*
+	 * pdata->power == false only if COLD_CD is available, otherwise only
+	 * in short time intervals during probing or resuming
+	 */
+	if (ios->power_mode == MMC_POWER_ON && ios->clock) {
+		if (!pdata->power) {
 			pm_runtime_get_sync(&host->pdev->dev);
 			pdata->power = true;
 		}
+		tmio_mmc_set_clock(host, ios->clock);
 		/* power up SD bus */
 		if (host->set_pwr)
 			host->set_pwr(host->pdev, 1);
-	} else if (ios->power_mode == MMC_POWER_OFF || !ios->clock) {
-		/* power down SD bus */
-		if (ios->power_mode == MMC_POWER_OFF) {
+		/* start bus clock */
+		tmio_mmc_clk_start(host);
+	} else if (ios->power_mode != MMC_POWER_UP) {
 		if (host->set_pwr)
 			host->set_pwr(host->pdev, 0);
 		if ((pdata->flags & TMIO_MMC_HAS_COLD_CD) &&
@@ -765,11 +769,7 @@ static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 			pdata->power = false;
 			pm_runtime_put(&host->pdev->dev);
 		}
-		}
 		tmio_mmc_clk_stop(host);
-	} else {
-		/* start bus clock */
-		tmio_mmc_clk_start(host);
 	}
 
 	switch (ios->bus_width) {
@@ -897,8 +897,10 @@ int __devinit tmio_mmc_host_probe(struct tmio_mmc_host **host,
 	tmio_mmc_request_dma(_host, pdata);
 
 	/* We have to keep the device powered for its card detection to work */
-	if (!(pdata->flags & TMIO_MMC_HAS_COLD_CD))
+	if (!(pdata->flags & TMIO_MMC_HAS_COLD_CD)) {
+		pdata->power = true;
 		pm_runtime_get_noresume(&pdev->dev);
+	}
 
 	mmc_add_host(mmc);
 
@@ -975,11 +977,16 @@ int tmio_mmc_host_resume(struct device *dev)
 	/* The MMC core will perform the complete set up */
 	host->pdata->power = false;
 
+	host->pm_global = true;
 	if (!host->pm_error)
 		pm_runtime_get_sync(dev);
 
-	tmio_mmc_reset(mmc_priv(mmc));
+	if (host->pm_global) {
+		/* Runtime PM resume callback didn't run */
+		tmio_mmc_reset(host);
 		tmio_mmc_request_dma(host, host->pdata);
+		host->pm_global = false;
+	}
 
 	return mmc_resume_host(mmc);
 }
@@ -1000,12 +1007,15 @@ int tmio_mmc_host_runtime_resume(struct device *dev)
 	struct tmio_mmc_data *pdata = host->pdata;
 
 	tmio_mmc_reset(host);
+	tmio_mmc_request_dma(host, host->pdata);
 
 	if (pdata->power) {
 		/* Only entered after a card-insert interrupt */
+		if (!mmc->card)
 			tmio_mmc_set_ios(mmc, &mmc->ios);
 		mmc_detect_change(mmc, msecs_to_jiffies(100));
 	}
+	host->pm_global = false;
 
 	return 0;
 }