arch/arm/mach-shmobile/cpuidle.c

   1 /*
   2  * CPUIdle support code for SH-Mobile ARM
   3  *
   4  *  Copyright (C) 2011 Magnus Damm
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License.  See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  */
  10
  11 #include <linux/pm.h>
  12 #include <linux/cpuidle.h>
  13 #include <linux/suspend.h>
  14 #include <linux/module.h>
  15 #include <linux/err.h>
  16 #include <asm/system.h>
  17 #include <asm/io.h>
  18
  19 static void shmobile_enter_wfi(void)
  20 {
  21         cpu_do_idle();
  22 }
  23
  24 void (*shmobile_cpuidle_modes[CPUIDLE_STATE_MAX])(void) = {
  25         shmobile_enter_wfi, /* regular sleep mode */
  26 };
  27
  28 static int shmobile_cpuidle_enter(struct cpuidle_device *dev,
  29                                   struct cpuidle_driver *drv,
  30                                   int index)
  31 {
  32         ktime_t before, after;
  33
  34         before = ktime_get();
  35
  36         local_irq_disable();
  37         local_fiq_disable();
  38
  39         shmobile_cpuidle_modes[index]();
  40
  41         local_irq_enable();
  42         local_fiq_enable();
  43
  44         after = ktime_get();
  45         dev->last_residency = ktime_to_ns(ktime_sub(after, before)) >> 10;
  46
  47         return index;
  48 }
  49
  50 static struct cpuidle_device shmobile_cpuidle_dev;
  51 static struct cpuidle_driver shmobile_cpuidle_driver = {
  52         .name =         "shmobile_cpuidle",
  53         .owner =        THIS_MODULE,
  54         .states[0] = {
  55                 .name = "C1",
  56                 .desc = "WFI",
  57                 .exit_latency = 1,
  58                 .target_residency = 1 * 2,
  59                 .flags = CPUIDLE_FLAG_TIME_VALID,
  60         },
  61         .safe_state_index = 0, /* C1 */
  62         .state_count = 1,
  63 };
  64
  65 void (*shmobile_cpuidle_setup)(struct cpuidle_driver *drv);
  66
  67 static int shmobile_cpuidle_init(void)
  68 {
  69         struct cpuidle_device *dev = &shmobile_cpuidle_dev;
  70         struct cpuidle_driver *drv = &shmobile_cpuidle_driver;
  71         int i;
  72
  73         for (i = 0; i < CPUIDLE_STATE_MAX; i++)
  74                 drv->states[i].enter = shmobile_cpuidle_enter;
  75
  76         if (shmobile_cpuidle_setup)
  77                 shmobile_cpuidle_setup(drv);
  78
  79         cpuidle_register_driver(drv);
  80
  81         dev->state_count = drv->state_count;
  82         cpuidle_register_device(dev);
  83
  84         return 0;
  85 }
  86 late_initcall(shmobile_cpuidle_init);