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 <mach/regs-sys.h>
  24 #include <mach/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         struct timeval before, after;
  31         unsigned long tmp;
  32         int idle_time;
  33
  34         local_irq_disable();
  35         do_gettimeofday(&before);
  36
  37         /* Setup PWRCFG to enter idle mode */
  38         tmp = __raw_readl(S3C64XX_PWR_CFG);
  39         tmp &= ~S3C64XX_PWRCFG_CFG_WFI_MASK;
  40         tmp |= S3C64XX_PWRCFG_CFG_WFI_IDLE;
  41         __raw_writel(tmp, S3C64XX_PWR_CFG);
  42
  43         cpu_do_idle();
  44
  45         do_gettimeofday(&after);
  46         local_irq_enable();
  47         idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC +
  48                     (after.tv_usec - before.tv_usec);
  49
  50         dev->last_residency = idle_time;
  51         return index;
  52 }
  53
  54 static DEFINE_PER_CPU(struct cpuidle_device, s3c64xx_cpuidle_device);
  55
  56 static struct cpuidle_driver s3c64xx_cpuidle_driver = {
  57         .name   = "s3c64xx_cpuidle",
  58         .owner  = THIS_MODULE,
  59         .states = {
  60                 {
  61                         .enter            = s3c64xx_enter_idle,
  62                         .exit_latency     = 1,
  63                         .target_residency = 1,
  64                         .flags            = CPUIDLE_FLAG_TIME_VALID,
  65                         .name             = "IDLE",
  66                         .desc             = "System active, ARM gated",
  67                 },
  68         },
  69         .state_count = 1,
  70 };
  71
  72 static int __init s3c64xx_init_cpuidle(void)
  73 {
  74         int ret;
  75
  76         cpuidle_register_driver(&s3c64xx_cpuidle_driver);
  77
  78         ret = cpuidle_register_device(&s3c64xx_cpuidle_device);
  79         if (ret) {
  80                 pr_err("Failed to register cpuidle device: %d\n", ret);
  81                 return ret;
  82         }
  83
  84         return 0;
  85 }
  86 device_initcall(s3c64xx_init_cpuidle);