arch/arm/mach-s3c64xx/cpuidle.c

   1 /* linux/arch/arm/mach-s3c64xx/cpuidle.c
   2  *
   3  * Copyright (c) 2011 Wolfson Microelectronics, plc
   4  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
   5  *              http://www.samsung.com
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10 */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/cpuidle.h>
  15 #include <linux/io.h>
  16 #include <linux/export.h>
  17 #include <linux/time.h>
  18
  19 #include <asm/proc-fns.h>
  20
  21 #include <mach/map.h>
  22
  23 #include "regs-sys.h"
  24 #include "regs-syscon-power.h"
  25
  26 static int s3c64xx_enter_idle(struct cpuidle_device *dev,
  27                               struct cpuidle_driver *drv,
  28                               int index)
  29 {
  30         unsigned long tmp;
  31
  32         /* Setup PWRCFG to enter idle mode */
  33         tmp = __raw_readl(S3C64XX_PWR_CFG);
  34         tmp &= ~S3C64XX_PWRCFG_CFG_WFI_MASK;
  35         tmp |= S3C64XX_PWRCFG_CFG_WFI_IDLE;
  36         __raw_writel(tmp, S3C64XX_PWR_CFG);
  37
  38         cpu_do_idle();
  39
  40         return index;
  41 }
  42
  43 static DEFINE_PER_CPU(struct cpuidle_device, s3c64xx_cpuidle_device);
  44
  45 static struct cpuidle_driver s3c64xx_cpuidle_driver = {
  46         .name   = "s3c64xx_cpuidle",
  47         .owner  = THIS_MODULE,
  48         .en_core_tk_irqen = 1,
  49         .states = {
  50                 {
  51                         .enter            = s3c64xx_enter_idle,
  52                         .exit_latency     = 1,
  53                         .target_residency = 1,
  54                         .flags            = CPUIDLE_FLAG_TIME_VALID,
  55                         .name             = "IDLE",
  56                         .desc             = "System active, ARM gated",
  57                 },
  58         },
  59         .state_count = 1,
  60 };
  61
  62 static int __init s3c64xx_init_cpuidle(void)
  63 {
  64         int ret;
  65
  66         cpuidle_register_driver(&s3c64xx_cpuidle_driver);
  67
  68         ret = cpuidle_register_device(&s3c64xx_cpuidle_device);
  69         if (ret) {
  70                 pr_err("Failed to register cpuidle device: %d\n", ret);
  71                 return ret;
  72         }
  73
  74         return 0;
  75 }
  76 device_initcall(s3c64xx_init_cpuidle);