ARM: S3C64XX: Add basic cpuidle driver

# PM

obj-$(CONFIG_PM)		+= pm.o irq-pm.o sleep.o

obj-$(CONFIG_CPU_IDLE)		+= cpuidle.o

# DMA support

/* 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);