[PATCH V1] ARM: Samsung: Basic CPUIDLE Support - linaro-dev

18 Mar 2011

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: Amit Daniel Kachhap amit.kachhap@linaro.org
---
FIX: Fixed the merging issue reported by Nicolas Pitre nicolas.pitre@linaro.org
Sending the rebased 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-exynos4/Makefile  |    1 +
 arch/arm/mach-exynos4/cpuidle.c |   87 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/mach-exynos4/cpuidle.c

diff --git a/arch/arm/mach-exynos4/Makefile b/arch/arm/mach-exynos4/Makefile
index b8f0e7d..f8a3a74 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 0000000..a543a18
--- /dev/null
+++ b/arch/arm/mach-exynos4/cpuidle.c
@@ -0,0 +1,87 @@
+/* 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);
-- 
1.7.1



    