diff options
author | Mark Brown <broonie@opensource.wolfsonmicro.com> | 2011-12-24 11:38:27 +0900 |
---|---|---|
committer | Kukjin Kim <kgene.kim@samsung.com> | 2012-01-20 09:39:52 +0900 |
commit | 2abf13c9ffdcde537fc54b83f1bcd50cc758beca (patch) | |
tree | d74405613d53e34d95a5ee3c812d84580bfac9df | |
parent | dcd6c92267155e70a94b3927bce681ce74b80d1f (diff) |
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>
-rw-r--r-- | arch/arm/mach-s3c64xx/Makefile | 1 | ||||
-rw-r--r-- | arch/arm/mach-s3c64xx/cpuidle.c | 91 |
2 files changed, 92 insertions, 0 deletions
diff --git a/arch/arm/mach-s3c64xx/Makefile b/arch/arm/mach-s3c64xx/Makefile index 1822ac2eba3..610fe2807ed 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 00000000000..625d2c7b454 --- /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); |