Merge branch 'pm-cpuidle'

* pm-cpuidle:
  PM / suspend: Always use deepest C-state in the "freeze" sleep state
  cpuidle / menu: move repeated correction factor check to init
  cpuidle / menu: Return (-1) if there are no suitable states
  cpuidle: Combine cpuidle_enabled() with cpuidle_select()
  ARM: clps711x: Add cpuidle driver

drivers/cpuidle/Kconfig.arm

@@ -13,6 +13,12 @@ config ARM_BIG_LITTLE_CPUIDLE
 	  define different C-states for little and big cores through the
 	  multiple CPU idle drivers infrastructure.
 
+config ARM_CLPS711X_CPUIDLE
+	bool "CPU Idle Driver for CLPS711X processors"
+	depends on ARCH_CLPS711X || COMPILE_TEST
+	help
+	  Select this to enable cpuidle on Cirrus Logic CLPS711X SOCs.
+
 config ARM_HIGHBANK_CPUIDLE
 	bool "CPU Idle Driver for Calxeda processors"
 	depends on ARM_PSCI

drivers/cpuidle/Makefile

@@ -8,6 +8,7 @@ obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o
 ##################################################################################
 # ARM SoC drivers
 obj-$(CONFIG_ARM_BIG_LITTLE_CPUIDLE)	+= cpuidle-big_little.o
+obj-$(CONFIG_ARM_CLPS711X_CPUIDLE)	+= cpuidle-clps711x.o
 obj-$(CONFIG_ARM_HIGHBANK_CPUIDLE)	+= cpuidle-calxeda.o
 obj-$(CONFIG_ARM_KIRKWOOD_CPUIDLE)	+= cpuidle-kirkwood.o
 obj-$(CONFIG_ARM_ZYNQ_CPUIDLE)		+= cpuidle-zynq.o

drivers/cpuidle/cpuidle-clps711x.c

@@ -0,0 +1,64 @@
+/*
+ *  CLPS711X CPU idle driver
+ *
+ *  Copyright (C) 2014 Alexander Shiyan <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/cpuidle.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define CLPS711X_CPUIDLE_NAME	"clps711x-cpuidle"
+
+static void __iomem *clps711x_halt;
+
+static int clps711x_cpuidle_halt(struct cpuidle_device *dev,
+				 struct cpuidle_driver *drv, int index)
+{
+	writel(0xaa, clps711x_halt);
+
+	return index;
+}
+
+static struct cpuidle_driver clps711x_idle_driver = {
+	.name		= CLPS711X_CPUIDLE_NAME,
+	.owner		= THIS_MODULE,
+	.states[0]	= {
+		.name		= "HALT",
+		.desc		= "CLPS711X HALT",
+		.enter		= clps711x_cpuidle_halt,
+		.exit_latency	= 1,
+	},
+	.state_count	= 1,
+};
+
+static int __init clps711x_cpuidle_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	clps711x_halt = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(clps711x_halt))
+		return PTR_ERR(clps711x_halt);
+
+	return cpuidle_register(&clps711x_idle_driver, NULL);
+}
+
+static struct platform_driver clps711x_cpuidle_driver = {
+	.driver	= {
+		.name	= CLPS711X_CPUIDLE_NAME,
+		.owner	= THIS_MODULE,
+	},
+};
+module_platform_driver_probe(clps711x_cpuidle_driver, clps711x_cpuidle_probe);
+
+MODULE_AUTHOR("Alexander Shiyan <[email protected]>");
+MODULE_DESCRIPTION("CLPS711X CPU idle driver");
+MODULE_LICENSE("GPL");

drivers/cpuidle/cpuidle.c

@@ -32,6 +32,7 @@ LIST_HEAD(cpuidle_detected_devices);
 static int enabled_devices;
 static int off __read_mostly;
 static int initialized __read_mostly;
+static bool use_deepest_state __read_mostly;
 
 int cpuidle_disabled(void)
 {
@@ -65,23 +66,42 @@ int cpuidle_play_dead(void)
 }
 
 /**
- * cpuidle_enabled - check if the cpuidle framework is ready
- * @dev: cpuidle device for this cpu
- * @drv: cpuidle driver for this cpu
+ * cpuidle_use_deepest_state - Enable/disable the "deepest idle" mode.
+ * @enable: Whether enable or disable the feature.
+ *
+ * If the "deepest idle" mode is enabled, cpuidle will ignore the governor and
+ * always use the state with the greatest exit latency (out of the states that
+ * are not disabled).
  *
- * Return 0 on success, otherwise:
- * -NODEV : the cpuidle framework is not available
- * -EBUSY : the cpuidle framework is not initialized
+ * This function can only be called after cpuidle_pause() to avoid races.
  */
-int cpuidle_enabled(struct cpuidle_driver *drv, struct cpuidle_device *dev)
+void cpuidle_use_deepest_state(bool enable)
 {
-	if (off || !initialized)
-		return -ENODEV;
+	use_deepest_state = enable;
+}
 
-	if (!drv || !dev || !dev->enabled)
-		return -EBUSY;
+/**
+ * cpuidle_find_deepest_state - Find the state of the greatest exit latency.
+ * @drv: cpuidle driver for a given CPU.
+ * @dev: cpuidle device for a given CPU.
+ */
+static int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
+				      struct cpuidle_device *dev)
+{
+	unsigned int latency_req = 0;
+	int i, ret = CPUIDLE_DRIVER_STATE_START - 1;
 
-	return 0;
+	for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
+		struct cpuidle_state *s = &drv->states[i];
+		struct cpuidle_state_usage *su = &dev->states_usage[i];
+
+		if (s->disabled || su->disable || s->exit_latency <= latency_req)
+			continue;
+
+		latency_req = s->exit_latency;
+		ret = i;
+	}
+	return ret;
 }
 
 /**
@@ -138,6 +158,15 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
  */
 int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 {
+	if (off || !initialized)
+		return -ENODEV;
+
+	if (!drv || !dev || !dev->enabled)
+		return -EBUSY;
+
+	if (unlikely(use_deepest_state))
+		return cpuidle_find_deepest_state(drv, dev);
+
 	return cpuidle_curr_governor->select(drv, dev);
 }
 
@@ -169,7 +198,7 @@ int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev,
  */
 void cpuidle_reflect(struct cpuidle_device *dev, int index)
 {
-	if (cpuidle_curr_governor->reflect)
+	if (cpuidle_curr_governor->reflect && !unlikely(use_deepest_state))
 		cpuidle_curr_governor->reflect(dev, index);
 }
 

drivers/cpuidle/governors/menu.c

@@ -296,7 +296,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 		data->needs_update = 0;
 	}
 
-	data->last_state_idx = 0;
+	data->last_state_idx = CPUIDLE_DRIVER_STATE_START - 1;
 
 	/* Special case when user has set very strict latency requirement */
 	if (unlikely(latency_req == 0))
@@ -310,13 +310,6 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 
 	data->bucket = which_bucket(data->next_timer_us);
 
-	/*
-	 * if the correction factor is 0 (eg first time init or cpu hotplug
-	 * etc), we actually want to start out with a unity factor.
-	 */
-	if (data->correction_factor[data->bucket] == 0)
-		data->correction_factor[data->bucket] = RESOLUTION * DECAY;
-
 	/*
 	 * Force the result of multiplication to be 64 bits even if both
 	 * operands are 32 bits.
@@ -466,9 +459,17 @@ static int menu_enable_device(struct cpuidle_driver *drv,
 				struct cpuidle_device *dev)
 {
 	struct menu_device *data = &per_cpu(menu_devices, dev->cpu);
+	int i;
 
 	memset(data, 0, sizeof(struct menu_device));
 
+	/*
+	 * if the correction factor is 0 (eg first time init or cpu hotplug
+	 * etc), we actually want to start out with a unity factor.
+	 */
+	for(i = 0; i < BUCKETS; i++)
+		data->correction_factor[i] = RESOLUTION * DECAY;
+
 	return 0;
 }
 

include/linux/cpuidle.h

@@ -120,8 +120,6 @@ struct cpuidle_driver {
 #ifdef CONFIG_CPU_IDLE
 extern void disable_cpuidle(void);
 
-extern int cpuidle_enabled(struct cpuidle_driver *drv,
-			  struct cpuidle_device *dev);
 extern int cpuidle_select(struct cpuidle_driver *drv,
 			  struct cpuidle_device *dev);
 extern int cpuidle_enter(struct cpuidle_driver *drv,
@@ -145,13 +143,11 @@ extern void cpuidle_resume(void);
 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 extern int cpuidle_play_dead(void);
+extern void cpuidle_use_deepest_state(bool enable);
 
 extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
 #else
 static inline void disable_cpuidle(void) { }
-static inline int cpuidle_enabled(struct cpuidle_driver *drv,
-				  struct cpuidle_device *dev)
-{return -ENODEV; }
 static inline int cpuidle_select(struct cpuidle_driver *drv,
 				 struct cpuidle_device *dev)
 {return -ENODEV; }
@@ -180,6 +176,7 @@ static inline int cpuidle_enable_device(struct cpuidle_device *dev)
 {return -ENODEV; }
 static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
 static inline int cpuidle_play_dead(void) {return -ENODEV; }
+static inline void cpuidle_use_deepest_state(bool enable) {}
 static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
 	struct cpuidle_device *dev) {return NULL; }
 #endif

kernel/power/suspend.c

@@ -54,9 +54,11 @@ static void freeze_begin(void)
 
 static void freeze_enter(void)
 {
+	cpuidle_use_deepest_state(true);
 	cpuidle_resume();
 	wait_event(suspend_freeze_wait_head, suspend_freeze_wake);
 	cpuidle_pause();
+	cpuidle_use_deepest_state(false);
 }
 
 void freeze_wake(void)

kernel/sched/idle.c

@@ -101,19 +101,13 @@ static int cpuidle_idle_call(void)
 	rcu_idle_enter();
 
 	/*
-	 * Check if the cpuidle framework is ready, otherwise fallback
-	 * to the default arch specific idle method
+	 * Ask the cpuidle framework to choose a convenient idle state.
+	 * Fall back to the default arch specific idle method on errors.
 	 */
-	ret = cpuidle_enabled(drv, dev);
-
-	if (!ret) {
-		/*
-		 * Ask the governor to choose an idle state it thinks
-		 * it is convenient to go to. There is *always* a
-		 * convenient idle state
-		 */
-		next_state = cpuidle_select(drv, dev);
+	next_state = cpuidle_select(drv, dev);
 
+	ret = next_state;
+	if (ret >= 0) {
 		/*
 		 * The idle task must be scheduled, it is pointless to
 		 * go to idle, just update no idle residency and get
@@ -140,7 +134,7 @@ static int cpuidle_idle_call(void)
 					CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
 					&dev->cpu);
 
-			if (!ret) {
+			if (ret >= 0) {
 				trace_cpu_idle_rcuidle(next_state, dev->cpu);
 
 				/*
@@ -175,7 +169,7 @@ static int cpuidle_idle_call(void)
 	 * We can't use the cpuidle framework, let's use the default
 	 * idle routine
 	 */
-	if (ret)
+	if (ret < 0)
 		arch_cpu_idle();
 
 	__current_set_polling();