release/src-rt-6.x.4708/linux/linux-2.6.36/arch/sh/kernel/cpu/shmobile/cpuidle.c

   1 /*
   2  * arch/sh/kernel/cpu/shmobile/cpuidle.c
   3  *
   4  * Cpuidle support code for SuperH Mobile
   5  *
   6  *  Copyright (C) 2009 Magnus Damm
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  */
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/io.h>
  15 #include <linux/suspend.h>
  16 #include <linux/cpuidle.h>
  17 #include <asm/suspend.h>
  18 #include <asm/uaccess.h>
  19 #include <asm/hwblk.h>
  20
  21 static unsigned long cpuidle_mode[] = {
  22         SUSP_SH_SLEEP, /* regular sleep mode */
  23         SUSP_SH_SLEEP | SUSP_SH_SF, /* sleep mode + self refresh */
  24         SUSP_SH_STANDBY | SUSP_SH_SF, /* software standby mode + self refresh */
  25 };
  26
  27 static int cpuidle_sleep_enter(struct cpuidle_device *dev,
  28                                struct cpuidle_state *state)
  29 {
  30         unsigned long allowed_mode = arch_hwblk_sleep_mode();
  31         ktime_t before, after;
  32         int requested_state = state - &dev->states[0];
  33         int allowed_state;
  34         int k;
  35
  36         /* convert allowed mode to allowed state */
  37         for (k = ARRAY_SIZE(cpuidle_mode) - 1; k > 0; k--)
  38                 if (cpuidle_mode[k] == allowed_mode)
  39                         break;
  40
  41         allowed_state = k;
  42
  43         /* take the following into account for sleep mode selection:
  44          * - allowed_state: best mode allowed by hardware (clock deps)
  45          * - requested_state: best mode allowed by software (latencies)
  46          */
  47         k = min_t(int, allowed_state, requested_state);
  48
  49         dev->last_state = &dev->states[k];
  50         before = ktime_get();
  51         sh_mobile_call_standby(cpuidle_mode[k]);
  52         after = ktime_get();
  53         return ktime_to_ns(ktime_sub(after, before)) >> 10;
  54 }
  55
  56 static struct cpuidle_device cpuidle_dev;
  57 static struct cpuidle_driver cpuidle_driver = {
  58         .name =         "sh_idle",
  59         .owner =        THIS_MODULE,
  60 };
  61
  62 void sh_mobile_setup_cpuidle(void)
  63 {
  64         struct cpuidle_device *dev = &cpuidle_dev;
  65         struct cpuidle_state *state;
  66         int i;
  67
  68         cpuidle_register_driver(&cpuidle_driver);
  69
  70         for (i = 0; i < CPUIDLE_STATE_MAX; i++) {
  71                 dev->states[i].name[0] = '\0';
  72                 dev->states[i].desc[0] = '\0';
  73         }
  74
  75         i = CPUIDLE_DRIVER_STATE_START;
  76
  77         state = &dev->states[i++];
  78         snprintf(state->name, CPUIDLE_NAME_LEN, "C0");
  79         strncpy(state->desc, "SuperH Sleep Mode", CPUIDLE_DESC_LEN);
  80         state->exit_latency = 1;
  81         state->target_residency = 1 * 2;
  82         state->power_usage = 3;
  83         state->flags = 0;
  84         state->flags |= CPUIDLE_FLAG_SHALLOW;
  85         state->flags |= CPUIDLE_FLAG_TIME_VALID;
  86         state->enter = cpuidle_sleep_enter;
  87
  88         dev->safe_state = state;
  89
  90         if (sh_mobile_sleep_supported & SUSP_SH_SF) {
  91                 state = &dev->states[i++];
  92                 snprintf(state->name, CPUIDLE_NAME_LEN, "C1");
  93                 strncpy(state->desc, "SuperH Sleep Mode [SF]",
  94                         CPUIDLE_DESC_LEN);
  95                 state->exit_latency = 100;
  96                 state->target_residency = 1 * 2;
  97                 state->power_usage = 1;
  98                 state->flags = 0;
  99                 state->flags |= CPUIDLE_FLAG_TIME_VALID;
 100                 state->enter = cpuidle_sleep_enter;
 101         }
 102
 103         if (sh_mobile_sleep_supported & SUSP_SH_STANDBY) {
 104                 state = &dev->states[i++];
 105                 snprintf(state->name, CPUIDLE_NAME_LEN, "C2");
 106                 strncpy(state->desc, "SuperH Mobile Standby Mode [SF]",
 107                         CPUIDLE_DESC_LEN);
 108                 state->exit_latency = 2300;
 109                 state->target_residency = 1 * 2;
 110                 state->power_usage = 1;
 111                 state->flags = 0;
 112                 state->flags |= CPUIDLE_FLAG_TIME_VALID;
 113                 state->enter = cpuidle_sleep_enter;
 114         }
 115
 116         dev->state_count = i;
 117
 118         cpuidle_register_device(dev);
 119 }