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authorMark Brown <broonie@opensource.wolfsonmicro.com>2011-12-24 11:38:27 +0900
committerKukjin Kim <kgene.kim@samsung.com>2012-01-20 09:39:52 +0900
commit2abf13c9ffdcde537fc54b83f1bcd50cc758beca (patch)
treed74405613d53e34d95a5ee3c812d84580bfac9df /arch/arm/mach-s3c64xx
parentdcd6c92267155e70a94b3927bce681ce74b80d1f (diff)
downloadop-kernel-dev-2abf13c9ffdcde537fc54b83f1bcd50cc758beca.zip
op-kernel-dev-2abf13c9ffdcde537fc54b83f1bcd50cc758beca.tar.gz
ARM: S3C64XX: Add basic cpuidle driver
Add a very basic cpuidle driver for S3C64xx which merely drives the CPU into IDLE mode. We could do this with pm_idle but the more modern idiom is to use cpuidle and the intention is to go further and support STOP and DEEP-STOP states in conjunction with the pm_domain framework. The actual state entry code was lifted from Tomasz Figa's work on spica. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Diffstat (limited to 'arch/arm/mach-s3c64xx')
-rw-r--r--arch/arm/mach-s3c64xx/Makefile1
-rw-r--r--arch/arm/mach-s3c64xx/cpuidle.c91
2 files changed, 92 insertions, 0 deletions
diff --git a/arch/arm/mach-s3c64xx/Makefile b/arch/arm/mach-s3c64xx/Makefile
index 1822ac2..610fe28 100644
--- a/arch/arm/mach-s3c64xx/Makefile
+++ b/arch/arm/mach-s3c64xx/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_CPU_S3C6410) += s3c6410.o
# PM
obj-$(CONFIG_PM) += pm.o irq-pm.o sleep.o
+obj-$(CONFIG_CPU_IDLE) += cpuidle.o
# DMA support
diff --git a/arch/arm/mach-s3c64xx/cpuidle.c b/arch/arm/mach-s3c64xx/cpuidle.c
new file mode 100644
index 0000000..625d2c7
--- /dev/null
+++ b/arch/arm/mach-s3c64xx/cpuidle.c
@@ -0,0 +1,91 @@
+/* linux/arch/arm/mach-s3c64xx/cpuidle.c
+ *
+ * Copyright (c) 2011 Wolfson Microelectronics, plc
+ * 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 <linux/export.h>
+#include <linux/time.h>
+
+#include <asm/proc-fns.h>
+
+#include <mach/map.h>
+
+#include <mach/regs-sys.h>
+#include <mach/regs-syscon-power.h>
+
+static int s3c64xx_enter_idle(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv,
+ int index)
+{
+ struct timeval before, after;
+ unsigned long tmp;
+ int idle_time;
+
+ local_irq_disable();
+ do_gettimeofday(&before);
+
+ /* Setup PWRCFG to enter idle mode */
+ tmp = __raw_readl(S3C64XX_PWR_CFG);
+ tmp &= ~S3C64XX_PWRCFG_CFG_WFI_MASK;
+ tmp |= S3C64XX_PWRCFG_CFG_WFI_IDLE;
+ __raw_writel(tmp, S3C64XX_PWR_CFG);
+
+ 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);
+
+ dev->last_residency = idle_time;
+ return index;
+}
+
+static struct cpuidle_state s3c64xx_cpuidle_set[] = {
+ [0] = {
+ .enter = s3c64xx_enter_idle,
+ .exit_latency = 1,
+ .target_residency = 100000,
+ .flags = CPUIDLE_FLAG_TIME_VALID,
+ .name = "IDLE",
+ .desc = "System active, ARM gated",
+ },
+};
+
+static struct cpuidle_driver s3c64xx_cpuidle_driver = {
+ .name = "s3c64xx_cpuidle",
+ .owner = THIS_MODULE,
+ .state_count = ARRAY_SIZE(s3c64xx_cpuidle_set),
+};
+
+static struct cpuidle_device s3c64xx_cpuidle_device = {
+ .state_count = ARRAY_SIZE(s3c64xx_cpuidle_set),
+};
+
+static int __init s3c64xx_init_cpuidle(void)
+{
+ int ret;
+
+ memcpy(s3c64xx_cpuidle_driver.states, s3c64xx_cpuidle_set,
+ sizeof(s3c64xx_cpuidle_set));
+ cpuidle_register_driver(&s3c64xx_cpuidle_driver);
+
+ ret = cpuidle_register_device(&s3c64xx_cpuidle_device);
+ if (ret) {
+ pr_err("Failed to register cpuidle device: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+device_initcall(s3c64xx_init_cpuidle);
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