ARM: EXYNOS4: CPUIDLE Support

This patch supports cpuidle framework for EXYNOS4210. Currently,
Only one idle state is possible to use, but more idle states can
be added following by this patch.

Signed-off-by: Jaecheol Lee <jc.lee@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/mach-exynos4/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_CPU_EXYNOS4210)	+= cpu.o init.o clock.o irq-combiner.o
 obj-$(CONFIG_CPU_EXYNOS4210)	+= setup-i2c0.o gpiolib.o irq-eint.o dma.o
 obj-$(CONFIG_PM)		+= pm.o sleep.o
 obj-$(CONFIG_CPU_FREQ)		+= cpufreq.o
+obj-$(CONFIG_CPU_IDLE)		+= cpuidle.o
 
 obj-$(CONFIG_SMP)		+= platsmp.o headsmp.o
 

arch/arm/mach-exynos4/cpuidle.c

@@ -0,0 +1,86 @@
+/* linux/arch/arm/mach-exynos4/cpuidle.c
+ *
+ * Copyright (c) 2011 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/cpuidle.h>
+#include <linux/io.h>
+
+#include <asm/proc-fns.h>
+
+static int exynos4_enter_idle(struct cpuidle_device *dev,
+			      struct cpuidle_state *state);
+
+static struct cpuidle_state exynos4_cpuidle_set[] = {
+	[0] = {
+		.enter			= exynos4_enter_idle,
+		.exit_latency		= 1,
+		.target_residency	= 100000,
+		.flags			= CPUIDLE_FLAG_TIME_VALID,
+		.name			= "IDLE",
+		.desc			= "ARM clock gating(WFI)",
+	},
+};
+
+static DEFINE_PER_CPU(struct cpuidle_device, exynos4_cpuidle_device);
+
+static struct cpuidle_driver exynos4_idle_driver = {
+	.name		= "exynos4_idle",
+	.owner		= THIS_MODULE,
+};
+
+static int exynos4_enter_idle(struct cpuidle_device *dev,
+			      struct cpuidle_state *state)
+{
+	struct timeval before, after;
+	int idle_time;
+
+	local_irq_disable();
+	do_gettimeofday(&before);
+
+	cpu_do_idle();
+
+	do_gettimeofday(&after);
+	local_irq_enable();
+	idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC +
+		    (after.tv_usec - before.tv_usec);
+
+	return idle_time;
+}
+
+static int __init exynos4_init_cpuidle(void)
+{
+	int i, max_cpuidle_state, cpu_id;
+	struct cpuidle_device *device;
+
+	cpuidle_register_driver(&exynos4_idle_driver);
+
+	for_each_cpu(cpu_id, cpu_online_mask) {
+		device = &per_cpu(exynos4_cpuidle_device, cpu_id);
+		device->cpu = cpu_id;
+
+		device->state_count = (sizeof(exynos4_cpuidle_set) /
+					       sizeof(struct cpuidle_state));
+
+		max_cpuidle_state = device->state_count;
+
+		for (i = 0; i < max_cpuidle_state; i++) {
+			memcpy(&device->states[i], &exynos4_cpuidle_set[i],
+					sizeof(struct cpuidle_state));
+		}
+
+		if (cpuidle_register_device(device)) {
+			printk(KERN_ERR "CPUidle register device failed\n,");
+			return -EIO;
+		}
+	}
+	return 0;
+}
+device_initcall(exynos4_init_cpuidle);