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_state *state)
  30 {
  31         ktime_t before, after;
  32         int requested_state = state - &dev->states[0];
  33
  34         dev->last_state = &dev->states[requested_state];
  35         before = ktime_get();
  36
  37         local_irq_disable();
  38         local_fiq_disable();
  39
  40         shmobile_cpuidle_modes[requested_state]();
  41
  42         local_irq_enable();
  43         local_fiq_enable();
  44
  45         after = ktime_get();
  46         return ktime_to_ns(ktime_sub(after, before)) >> 10;
  47 }
  48
  49 static struct cpuidle_device shmobile_cpuidle_dev;
  50 static struct cpuidle_driver shmobile_cpuidle_driver = {
  51         .name =         "shmobile_cpuidle",
  52         .owner =        THIS_MODULE,
  53 };
  54
  55 void (*shmobile_cpuidle_setup)(struct cpuidle_device *dev);
  56
  57 static int shmobile_cpuidle_init(void)
  58 {
  59         struct cpuidle_device *dev = &shmobile_cpuidle_dev;
  60         struct cpuidle_state *state;
  61         int i;
  62
  63         cpuidle_register_driver(&shmobile_cpuidle_driver);
  64
  65         for (i = 0; i < CPUIDLE_STATE_MAX; i++) {
  66                 dev->states[i].name[0] = '\0';
  67                 dev->states[i].desc[0] = '\0';
  68                 dev->states[i].enter = shmobile_cpuidle_enter;
  69         }
  70
  71         i = CPUIDLE_DRIVER_STATE_START;
  72
  73         state = &dev->states[i++];
  74         snprintf(state->name, CPUIDLE_NAME_LEN, "C1");
  75         strncpy(state->desc, "WFI", CPUIDLE_DESC_LEN);
  76         state->exit_latency = 1;
  77         state->target_residency = 1 * 2;
  78         state->power_usage = 3;
  79         state->flags = 0;
  80         state->flags |= CPUIDLE_FLAG_TIME_VALID;
  81
  82         dev->safe_state = state;
  83         dev->state_count = i;
  84
  85         if (shmobile_cpuidle_setup)
  86                 shmobile_cpuidle_setup(dev);
  87
  88         cpuidle_register_device(dev);
  89
  90         return 0;
  91 }
  92 late_initcall(shmobile_cpuidle_init);