mmc: tmio: fix unbalanced power-on calls with clock-gating enabled

With MMC clock gating enabled the MMC core currently calls MMC host driver's .set_ios() method with .power_mode == MMC_POWER_ON and the clock value set either to 0 or to the target rate. The tmio MMC driver then wrongly translates the latter calls to card slot power-on requests, even when the slot already was on. This patch fixes the driver to avoid needlessly incrementing power-supplying regulator's use count. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com> Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Chris Ball <cjb@laptop.org>

mmc: tmio: fix unbalanced power-on calls with clock-gating enabled
With MMC clock gating enabled the MMC core currently calls MMC host driver's .set_ios() method with .power_mode == MMC_POWER_ON and the clock value set either to 0 or to the target rate. The tmio MMC driver then wrongly translates the latter calls to card slot power-on requests, even when the slot already was on. This patch fixes the driver to avoid needlessly incrementing power-supplying regulator's use count. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com> Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Chris Ball <cjb@laptop.org>
Guennadi Liakhovetski · Chris Ball
1 parent 19f1ba51c7
Showing 2 changed files with 35 additions and 12 deletions Side-by-side Diff
drivers/mmc/host/tmio_mmc.h
drivers/mmc/host/tmio_mmc_pio.c
@@ -40,6 +40,22 @@
  
 struct tmio_mmc_data;
  
+/*
+ * We differentiate between the following 3 power states:
+ * 1. card slot powered off, controller stopped. This is used, when either there
+ *    is no card in the slot, or the card really has to be powered down.
+ * 2. card slot powered on, controller stopped. This is used, when a card is in
+ *    the slot, but no activity is currently taking place. This is a power-
+ *    saving mode with card-state preserved. This state can be entered, e.g.
+ *    when MMC clock-gating is used.
+ * 3. card slot powered on, controller running. This is the actual active state.
+ */
+enum tmio_mmc_power {
+	TMIO_MMC_OFF_STOP,	/* card power off, controller stopped */
+	TMIO_MMC_ON_STOP,	/* card power on, controller stopped */
+	TMIO_MMC_ON_RUN,	/* card power on, controller running */
+};
+
 struct tmio_mmc_host {
 	void __iomem *ctl;
 	unsigned long bus_shift;
@@ -48,8 +64,8 @@
 	struct mmc_data         *data;
 	struct mmc_host         *mmc;
  
-	/* Controller power state */
-	bool			power;
+	/* Controller and card power state */
+	enum tmio_mmc_power	power;
  
 	/* Callbacks for clock / power control */
 	void (*set_pwr)(struct platform_device *host, int state);
@@ -859,7 +859,7 @@
 	 * is kept positive, so no suspending actually takes place.
 	 */
 	if (ios->power_mode == MMC_POWER_ON && ios->clock) {
-		if (!host->power) {
+		if (host->power != TMIO_MMC_ON_RUN) {
 			tmio_mmc_clk_update(mmc);
 			pm_runtime_get_sync(dev);
 			if (host->resuming) {
  
  
  
  
  
@@ -868,27 +868,34 @@
 			}
 		}
 		tmio_mmc_set_clock(host, ios->clock);
-		if (!host->power) {
+		if (host->power == TMIO_MMC_OFF_STOP)
 			/* power up SD card and the bus */
 			tmio_mmc_power_on(host, ios->vdd);
-			host->power = true;
-		}
+		host->power = TMIO_MMC_ON_RUN;
 		/* start bus clock */
 		tmio_mmc_clk_start(host);
 	} else if (ios->power_mode != MMC_POWER_UP) {
-		if (host->power) {
-			struct tmio_mmc_data *pdata = host->pdata;
-			if (ios->power_mode == MMC_POWER_OFF)
+		struct tmio_mmc_data *pdata = host->pdata;
+		unsigned int old_power = host->power;
+
+		if (old_power != TMIO_MMC_OFF_STOP) {
+			if (ios->power_mode == MMC_POWER_OFF) {
 				tmio_mmc_power_off(host);
+				host->power = TMIO_MMC_OFF_STOP;
+			} else {
+				host->power = TMIO_MMC_ON_STOP;
+			}
+		}
+
+		if (old_power == TMIO_MMC_ON_RUN) {
 			tmio_mmc_clk_stop(host);
-			host->power = false;
 			pm_runtime_put(dev);
 			if (pdata->clk_disable)
 				pdata->clk_disable(host->pdev);
 		}
 	}
  
-	if (host->power) {
+	if (host->power != TMIO_MMC_OFF_STOP) {
 		switch (ios->bus_width) {
 		case MMC_BUS_WIDTH_1:
 			sd_ctrl_write16(host, CTL_SD_MEM_CARD_OPT, 0x80e0);
@@ -1029,7 +1036,7 @@
 				  mmc->caps & MMC_CAP_NONREMOVABLE ||
 				  mmc->slot.cd_irq >= 0);
  
-	_host->power = false;
+	_host->power = TMIO_MMC_OFF_STOP;
 	pm_runtime_enable(&pdev->dev);
 	ret = pm_runtime_resume(&pdev->dev);
 	if (ret < 0)
...	...	@@ -40,6 +40,22 @@
40	40
41	41	struct tmio_mmc_data;
42	42
	43	+/*
	44	+ * We differentiate between the following 3 power states:
	45	+ * 1. card slot powered off, controller stopped. This is used, when either there
	46	+ * is no card in the slot, or the card really has to be powered down.
	47	+ * 2. card slot powered on, controller stopped. This is used, when a card is in
	48	+ * the slot, but no activity is currently taking place. This is a power-
	49	+ * saving mode with card-state preserved. This state can be entered, e.g.
	50	+ * when MMC clock-gating is used.
	51	+ * 3. card slot powered on, controller running. This is the actual active state.
	52	+ */
	53	+enum tmio_mmc_power {
	54	+ TMIO_MMC_OFF_STOP, /* card power off, controller stopped */
	55	+ TMIO_MMC_ON_STOP, /* card power on, controller stopped */
	56	+ TMIO_MMC_ON_RUN, /* card power on, controller running */
	57	+};
	58	+
43	59	struct tmio_mmc_host {
44	60	void __iomem *ctl;
45	61	unsigned long bus_shift;
...	...	@@ -48,8 +64,8 @@
48	64	struct mmc_data *data;
49	65	struct mmc_host *mmc;
50	66
51		- /* Controller power state */
52		- bool power;
	67	+ /* Controller and card power state */
	68	+ enum tmio_mmc_power power;
53	69
54	70	/* Callbacks for clock / power control */
55	71	void (set_pwr)(struct platform_device host, int state);
...	...	@@ -859,7 +859,7 @@
859	859	* is kept positive, so no suspending actually takes place.
860	860	*/
861	861	if (ios->power_mode == MMC_POWER_ON && ios->clock) {
862		- if (!host->power) {
	862	+ if (host->power != TMIO_MMC_ON_RUN) {
863	863	tmio_mmc_clk_update(mmc);
864	864	pm_runtime_get_sync(dev);
865	865	if (host->resuming) {
866	866
867	867
868	868
869	869
870	870
...	...	@@ -868,27 +868,34 @@
868	868	}
869	869	}
870	870	tmio_mmc_set_clock(host, ios->clock);
871		- if (!host->power) {
	871	+ if (host->power == TMIO_MMC_OFF_STOP)
872	872	/* power up SD card and the bus */
873	873	tmio_mmc_power_on(host, ios->vdd);
874		- host->power = true;
875		- }
	874	+ host->power = TMIO_MMC_ON_RUN;
876	875	/* start bus clock */
877	876	tmio_mmc_clk_start(host);
878	877	} else if (ios->power_mode != MMC_POWER_UP) {
879		- if (host->power) {
880		- struct tmio_mmc_data *pdata = host->pdata;
881		- if (ios->power_mode == MMC_POWER_OFF)
	878	+ struct tmio_mmc_data *pdata = host->pdata;
	879	+ unsigned int old_power = host->power;
	880	+
	881	+ if (old_power != TMIO_MMC_OFF_STOP) {
	882	+ if (ios->power_mode == MMC_POWER_OFF) {
882	883	tmio_mmc_power_off(host);
	884	+ host->power = TMIO_MMC_OFF_STOP;
	885	+ } else {
	886	+ host->power = TMIO_MMC_ON_STOP;
	887	+ }
	888	+ }
	889	+
	890	+ if (old_power == TMIO_MMC_ON_RUN) {
883	891	tmio_mmc_clk_stop(host);
884		- host->power = false;
885	892	pm_runtime_put(dev);
886	893	if (pdata->clk_disable)
887	894	pdata->clk_disable(host->pdev);
888	895	}
889	896	}
890	897
891		- if (host->power) {
	898	+ if (host->power != TMIO_MMC_OFF_STOP) {
892	899	switch (ios->bus_width) {
893	900	case MMC_BUS_WIDTH_1:
894	901	sd_ctrl_write16(host, CTL_SD_MEM_CARD_OPT, 0x80e0);
...	...	@@ -1029,7 +1036,7 @@
1029	1036	mmc->caps & MMC_CAP_NONREMOVABLE \|\|
1030	1037	mmc->slot.cd_irq >= 0);
1031	1038
1032		- _host->power = false;
	1039	+ _host->power = TMIO_MMC_OFF_STOP;
1033	1040	pm_runtime_enable(&pdev->dev);
1034	1041	ret = pm_runtime_resume(&pdev->dev);
1035	1042	if (ret < 0)