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>

2 files changed, 39 insertions, 27 deletions

diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
index f0d7c4349793..ba0d8e66001d 100644
--- a/drivers/mmc/host/tmio_mmc.h
+++ b/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;
diff --git a/drivers/mmc/host/tmio_mmc_pio.c b/drivers/mmc/host/tmio_mmc_pio.c
index a2f76adbfd34..221ffb71c7a3 100644
--- a/drivers/mmc/host/tmio_mmc_pio.c
+++ b/drivers/mmc/host/tmio_mmc_pio.c
@@ -546,6 +546,7 @@ out:
 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;
         }
@@ -743,33 +746,30 @@ 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) {
-                        if (host->set_pwr)
-                                host->set_pwr(host->pdev, 0);
-                        if ((pdata->flags & TMIO_MMC_HAS_COLD_CD) &&
-                            pdata->power) {
-                                pdata->power = false;
-                                pm_runtime_put(&host->pdev->dev);
-                        }
-                }
-                tmio_mmc_clk_stop(host);
-        } else {
                 /* 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) &&
+                    pdata->power) {
+                        pdata->power = false;
+                        pm_runtime_put(&host->pdev->dev);
+                }
+                tmio_mmc_clk_stop(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));
-        tmio_mmc_request_dma(host, host->pdata);
+        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 */
-                tmio_mmc_set_ios(mmc, &mmc->ios);
+                if (!mmc->card)
+                        tmio_mmc_set_ios(mmc, &mmc->ios);
                 mmc_detect_change(mmc, msecs_to_jiffies(100));
         }
+        host->pm_global = false;
 
         return 0;
 }