arch/arm/mach-imx/cpuidle-imx6q.c

   1 /*
   2  * Copyright (C) 2012 Freescale Semiconductor, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/cpuidle.h>
  10 #include <linux/module.h>
  11 #include <asm/cpuidle.h>
  12
  13 #include "common.h"
  14 #include "cpuidle.h"
  15 #include "hardware.h"
  16
  17 static int num_idle_cpus = 0;
  18 static DEFINE_SPINLOCK(cpuidle_lock);
  19
  20 static int imx6q_enter_wait(struct cpuidle_device *dev,
  21                             struct cpuidle_driver *drv, int index)
  22 {
  23         spin_lock(&cpuidle_lock);
  24         if (++num_idle_cpus == num_online_cpus())
  25                 imx6_set_lpm(WAIT_UNCLOCKED);
  26         spin_unlock(&cpuidle_lock);
  27
  28         cpu_do_idle();
  29
  30         spin_lock(&cpuidle_lock);
  31         if (num_idle_cpus-- == num_online_cpus())
  32                 imx6_set_lpm(WAIT_CLOCKED);
  33         spin_unlock(&cpuidle_lock);
  34
  35         return index;
  36 }
  37
  38 static struct cpuidle_driver imx6q_cpuidle_driver = {
  39         .name = "imx6q_cpuidle",
  40         .owner = THIS_MODULE,
  41         .states = {
  42                 /* WFI */
  43                 ARM_CPUIDLE_WFI_STATE,
  44                 /* WAIT */
  45                 {
  46                         .exit_latency = 50,
  47                         .target_residency = 75,
  48                         .flags = CPUIDLE_FLAG_TIMER_STOP,
  49                         .enter = imx6q_enter_wait,
  50                         .name = "WAIT",
  51                         .desc = "Clock off",
  52                 },
  53         },
  54         .state_count = 2,
  55         .safe_state_index = 0,
  56 };
  57
  58 int __init imx6q_cpuidle_init(void)
  59 {
  60         /* Set INT_MEM_CLK_LPM bit to get a reliable WAIT mode support */
  61         imx6q_set_int_mem_clk_lpm(true);
  62
  63         return cpuidle_register(&imx6q_cpuidle_driver, NULL);
  64 }