From 2abf13c9ffdcde537fc54b83f1bcd50cc758beca Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Sat, 24 Dec 2011 11:38:27 +0900 Subject: [PATCH] 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 Signed-off-by: Kukjin Kim --- arch/arm/mach-s3c64xx/Makefile | 1 + arch/arm/mach-s3c64xx/cpuidle.c | 91 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 92 insertions(+) create mode 100644 arch/arm/mach-s3c64xx/cpuidle.c 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 +#include +#include +#include +#include +#include + +#include + +#include + +#include +#include + +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); -- 2.7.4