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>

2 files changed, 87 insertions, 0 deletions

diff --git a/arch/arm/mach-exynos4/Makefile b/arch/arm/mach-exynos4/Makefile
index 9be104f63c0b..de197d6648a2 100644
--- a/arch/arm/mach-exynos4/Makefile
+++ b/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
 
diff --git a/arch/arm/mach-exynos4/cpuidle.c b/arch/arm/mach-exynos4/cpuidle.c
new file mode 100644
index 000000000000..bf7e96f2793a
--- /dev/null
+++ b/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);