[PATCH] ARM: Samsung: Basic CPUIDLE Support

[Amit Daniel Kachhap]

This patch supports cpuidle framework for samsung S5PV310. Currently,
Only one idle state is possible to use, but more idle states can
be added followed by this patch.

Signed-off-by: Jaecheol Lee <jc.lee at samsung.com>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap at linaro.org>
---
Rebasing the patch for linaro 2.6.38 kernel. This patch adds basic cpuidle 
infrastructure and fixes the launchpad bug(bug id: 723543). This patch is 
under review in samsung mailing list. 
http://www.spinics.net/lists/linux-samsung-soc/msg04268.html

 arch/arm/mach-s5pv310/Makefile  |    1 +
 arch/arm/mach-s5pv310/cpuidle.c |   87 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/mach-s5pv310/cpuidle.c

diff --git a/arch/arm/mach-s5pv310/Makefile b/arch/arm/mach-s5pv310/Makefile
index 036fb38..c5db0fa 100644
--- a/arch/arm/mach-s5pv310/Makefile
+++ b/arch/arm/mach-s5pv310/Makefile
@@ -15,6 +15,7 @@ obj-				:=
 obj-$(CONFIG_CPU_S5PV310)	+= cpu.o init.o clock.o irq-combiner.o
 obj-$(CONFIG_CPU_S5PV310)	+= setup-i2c0.o time.o gpiolib.o irq-eint.o dma.o
 obj-$(CONFIG_CPU_FREQ)		+= cpufreq.o
+obj-$(CONFIG_CPU_IDLE)		+= cpuidle.o
 
 obj-$(CONFIG_SMP)		+= platsmp.o headsmp.o
 obj-$(CONFIG_LOCAL_TIMERS)	+= localtimer.o
diff --git a/arch/arm/mach-s5pv310/cpuidle.c b/arch/arm/mach-s5pv310/cpuidle.c
new file mode 100644
index 0000000..f35b537
--- /dev/null
+++ b/arch/arm/mach-s5pv310/cpuidle.c
@@ -0,0 +1,87 @@
+/* linux/arch/arm/mach-s5pv310/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 s5pv310_enter_idle(struct cpuidle_device *dev,
+			      struct cpuidle_state *state);
+
+static struct cpuidle_state s5pv310_cpuidle_set[] = {
+	[0] = {
+		.enter			= s5pv310_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, s5pv310_cpuidle_device);
+
+static struct cpuidle_driver s5pv310_idle_driver = {
+	.name		= "s5pv310_idle",
+	.owner		= THIS_MODULE,
+};
+
+static int s5pv310_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 s5pv310_init_cpuidle(void)
+{
+	int i, max_cpuidle_state, cpu_id;
+	struct cpuidle_device *device;
+
+	cpuidle_register_driver(&s5pv310_idle_driver);
+
+	for_each_cpu(cpu_id, cpu_online_mask) {
+		device = &per_cpu(s5pv310_cpuidle_device, cpu_id);
+		device->cpu = cpu_id;
+
+		device->state_count = (sizeof(s5pv310_cpuidle_set) /
+					       sizeof(struct cpuidle_state));
+
+		max_cpuidle_state = device->state_count;
+
+		for (i = 0; i < max_cpuidle_state; i++) {
+			memcpy(&device->states[i], &s5pv310_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(s5pv310_init_cpuidle);
-- 
1.7.1