cpuidle: Add common time keeping and irq enabling

Make necessary changes to implement time keeping and irq enabling
in the core cpuidle code.  This will allow the removal of these
functionalities from various platform cpuidle implementations whose
timekeeping and irq enabling follows the form in this common code.

Signed-off-by: Robert Lee <rob.lee@linaro.org>
Tested-by: Jean Pihet <j-pihet@ti.com>
Tested-by: Amit Daniel <amit.kachhap@linaro.org>
Tested-by: Robert Lee <rob.lee@linaro.org>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Len Brown <len.brown@intel.com>

arch/arm/include/asm/cpuidle.h

@@ -0,0 +1,29 @@
+#ifndef __ASM_ARM_CPUIDLE_H
+#define __ASM_ARM_CPUIDLE_H
+
+#ifdef CONFIG_CPU_IDLE
+extern int arm_cpuidle_simple_enter(struct cpuidle_device *dev,
+		struct cpuidle_driver *drv, int index);
+#else
+static inline int arm_cpuidle_simple_enter(struct cpuidle_device *dev,
+		struct cpuidle_driver *drv, int index) { return -ENODEV; }
+#endif
+
+/* Common ARM WFI state */
+#define ARM_CPUIDLE_WFI_STATE_PWR(p) {\
+	.enter                  = arm_cpuidle_simple_enter,\
+	.exit_latency           = 1,\
+	.target_residency       = 1,\
+	.power_usage		= p,\
+	.flags                  = CPUIDLE_FLAG_TIME_VALID,\
+	.name                   = "WFI",\
+	.desc                   = "ARM WFI",\
+}
+
+/*
+ * in case power_specified == 1, give a default WFI power value needed
+ * by some governors
+ */
+#define ARM_CPUIDLE_WFI_STATE ARM_CPUIDLE_WFI_STATE_PWR(UINT_MAX)
+
+#endif

arch/arm/kernel/Makefile

@@ -21,7 +21,7 @@ obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += compat.o
 
 obj-$(CONFIG_LEDS)		+= leds.o
 obj-$(CONFIG_OC_ETM)		+= etm.o
-
+obj-$(CONFIG_CPU_IDLE)		+= cpuidle.o
 obj-$(CONFIG_ISA_DMA_API)	+= dma.o
 obj-$(CONFIG_ARCH_ACORN)	+= ecard.o 
 obj-$(CONFIG_FIQ)		+= fiq.o fiqasm.o

arch/arm/kernel/cpuidle.c

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2012 Linaro Ltd.
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/cpuidle.h>
+#include <asm/proc-fns.h>
+
+int arm_cpuidle_simple_enter(struct cpuidle_device *dev,
+		struct cpuidle_driver *drv, int index)
+{
+	cpu_do_idle();
+
+	return index;
+}

drivers/cpuidle/cpuidle.c

@@ -53,6 +53,24 @@ static void cpuidle_kick_cpus(void) {}
 
 static int __cpuidle_register_device(struct cpuidle_device *dev);
 
+static inline int cpuidle_enter(struct cpuidle_device *dev,
+				struct cpuidle_driver *drv, int index)
+{
+	struct cpuidle_state *target_state = &drv->states[index];
+	return target_state->enter(dev, drv, index);
+}
+
+static inline int cpuidle_enter_tk(struct cpuidle_device *dev,
+			       struct cpuidle_driver *drv, int index)
+{
+	return cpuidle_wrap_enter(dev, drv, index, cpuidle_enter);
+}
+
+typedef int (*cpuidle_enter_t)(struct cpuidle_device *dev,
+			       struct cpuidle_driver *drv, int index);
+
+static cpuidle_enter_t cpuidle_enter_ops;
+
 /**
  * cpuidle_idle_call - the main idle loop
  *
@@ -63,7 +81,6 @@ int cpuidle_idle_call(void)
 {
 	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
 	struct cpuidle_driver *drv = cpuidle_get_driver();
-	struct cpuidle_state *target_state;
 	int next_state, entered_state;
 
 	if (off)
@@ -92,12 +109,10 @@ int cpuidle_idle_call(void)
 		return 0;
 	}
 
-	target_state = &drv->states[next_state];
-
 	trace_power_start(POWER_CSTATE, next_state, dev->cpu);
 	trace_cpu_idle(next_state, dev->cpu);
 
-	entered_state = target_state->enter(dev, drv, next_state);
+	entered_state = cpuidle_enter_ops(dev, drv, next_state);
 
 	trace_power_end(dev->cpu);
 	trace_cpu_idle(PWR_EVENT_EXIT, dev->cpu);
@@ -110,6 +125,8 @@ int cpuidle_idle_call(void)
 		dev->states_usage[entered_state].time +=
 				(unsigned long long)dev->last_residency;
 		dev->states_usage[entered_state].usage++;
+	} else {
+		dev->last_residency = 0;
 	}
 
 	/* give the governor an opportunity to reflect on the outcome */
@@ -164,6 +181,37 @@ void cpuidle_resume_and_unlock(void)
 
 EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
 
+/**
+ * cpuidle_wrap_enter - performs timekeeping and irqen around enter function
+ * @dev: pointer to a valid cpuidle_device object
+ * @drv: pointer to a valid cpuidle_driver object
+ * @index: index of the target cpuidle state.
+ */
+int cpuidle_wrap_enter(struct cpuidle_device *dev,
+				struct cpuidle_driver *drv, int index,
+				int (*enter)(struct cpuidle_device *dev,
+					struct cpuidle_driver *drv, int index))
+{
+	ktime_t time_start, time_end;
+	s64 diff;
+
+	time_start = ktime_get();
+
+	index = enter(dev, drv, index);
+
+	time_end = ktime_get();
+
+	local_irq_enable();
+
+	diff = ktime_to_us(ktime_sub(time_end, time_start));
+	if (diff > INT_MAX)
+		diff = INT_MAX;
+
+	dev->last_residency = (int) diff;
+
+	return index;
+}
+
 #ifdef CONFIG_ARCH_HAS_CPU_RELAX
 static int poll_idle(struct cpuidle_device *dev,
 		struct cpuidle_driver *drv, int index)
@@ -212,10 +260,11 @@ static void poll_idle_init(struct cpuidle_driver *drv) {}
 int cpuidle_enable_device(struct cpuidle_device *dev)
 {
 	int ret, i;
+	struct cpuidle_driver *drv = cpuidle_get_driver();
 
 	if (dev->enabled)
 		return 0;
-	if (!cpuidle_get_driver() || !cpuidle_curr_governor)
+	if (!drv || !cpuidle_curr_governor)
 		return -EIO;
 	if (!dev->state_count)
 		return -EINVAL;
@@ -226,13 +275,16 @@ int cpuidle_enable_device(struct cpuidle_device *dev)
 			return ret;
 	}
 
-	poll_idle_init(cpuidle_get_driver());
+	cpuidle_enter_ops = drv->en_core_tk_irqen ?
+		cpuidle_enter_tk : cpuidle_enter;
+
+	poll_idle_init(drv);
 
 	if ((ret = cpuidle_add_state_sysfs(dev)))
 		return ret;
 
 	if (cpuidle_curr_governor->enable &&
-	    (ret = cpuidle_curr_governor->enable(cpuidle_get_driver(), dev)))
+	    (ret = cpuidle_curr_governor->enable(drv, dev)))
 		goto fail_sysfs;
 
 	for (i = 0; i < dev->state_count; i++) {

include/linux/cpuidle.h

@@ -15,6 +15,7 @@
 #include <linux/list.h>
 #include <linux/kobject.h>
 #include <linux/completion.h>
+#include <linux/hrtimer.h>
 
 #define CPUIDLE_STATE_MAX	8
 #define CPUIDLE_NAME_LEN	16
@@ -122,6 +123,8 @@ struct cpuidle_driver {
 	struct module 		*owner;
 
 	unsigned int		power_specified:1;
+	/* set to 1 to use the core cpuidle time keeping (for all states). */
+	unsigned int		en_core_tk_irqen:1;
 	struct cpuidle_state	states[CPUIDLE_STATE_MAX];
 	int			state_count;
 	int			safe_state_index;
@@ -140,7 +143,10 @@ extern void cpuidle_pause_and_lock(void);
 extern void cpuidle_resume_and_unlock(void);
 extern int cpuidle_enable_device(struct cpuidle_device *dev);
 extern void cpuidle_disable_device(struct cpuidle_device *dev);
-
+extern int cpuidle_wrap_enter(struct cpuidle_device *dev,
+				struct cpuidle_driver *drv, int index,
+				int (*enter)(struct cpuidle_device *dev,
+					struct cpuidle_driver *drv, int index));
 #else
 static inline void disable_cpuidle(void) { }
 static inline int cpuidle_idle_call(void) { return -ENODEV; }
@@ -157,6 +163,11 @@ static inline void cpuidle_resume_and_unlock(void) { }
 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_wrap_enter(struct cpuidle_device *dev,
+				struct cpuidle_driver *drv, int index,
+				int (*enter)(struct cpuidle_device *dev,
+					struct cpuidle_driver *drv, int index))
+{ return -ENODEV; }
 
 #endif