cpuidle.c

   1 /*
   2  * Copyright (C) 2012 ROCKCHIP, 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 #define pr_fmt(fmt) "cpuidle: %s: " fmt, __func__
  10
  11 #include <linux/pm.h>
  12 #include <linux/cpuidle.h>
  13 #include <linux/suspend.h>
  14 #include <linux/err.h>
  15
  16 #include <asm/hardware/gic.h>
  17 #include <asm/io.h>
  18
  19 static bool rk30_gic_interrupt_pending(void)
  20 {
  21         return (readl_relaxed(RK30_GICC_BASE + GIC_CPU_HIGHPRI) != 0x3FF);
  22 }
  23
  24 static void rk30_wfi_until_interrupt(void)
  25 {
  26 retry:
  27         cpu_do_idle();
  28
  29         if (!rk30_gic_interrupt_pending())
  30                 goto retry;
  31 }
  32
  33 static int rk30_idle(struct cpuidle_device *dev, struct cpuidle_state *state)
  34 {
  35         ktime_t preidle, postidle;
  36
  37         local_fiq_disable();
  38
  39         preidle = ktime_get();
  40
  41         rk30_wfi_until_interrupt();
  42
  43         postidle = ktime_get();
  44
  45         local_fiq_enable();
  46         local_irq_enable();
  47
  48         return ktime_to_us(ktime_sub(postidle, preidle));
  49 }
  50
  51 static DEFINE_PER_CPU(struct cpuidle_device, rk30_cpuidle_device);
  52
  53 static __initdata struct cpuidle_state rk30_cpuidle_states[] = {
  54         {
  55                 .name = "C1",
  56                 .desc = "idle",
  57                 .flags = CPUIDLE_FLAG_TIME_VALID,
  58                 .exit_latency = 0,
  59                 .target_residency = 0,
  60                 .enter = rk30_idle,
  61         },
  62 };
  63
  64 static struct cpuidle_driver rk30_cpuidle_driver = {
  65         .name = "rk30_cpuidle",
  66         .owner = THIS_MODULE,
  67 };
  68
  69 static int __init rk30_cpuidle_init(void)
  70 {
  71         struct cpuidle_device *dev;
  72         unsigned int cpu;
  73         int ret;
  74
  75         ret = cpuidle_register_driver(&rk30_cpuidle_driver);
  76         if (ret) {
  77                 pr_err("failed to register cpuidle driver: %d\n", ret);
  78                 return ret;
  79         }
  80
  81         for_each_possible_cpu(cpu) {
  82                 dev = &per_cpu(rk30_cpuidle_device, cpu);
  83                 dev->cpu = cpu;
  84                 dev->state_count = ARRAY_SIZE(rk30_cpuidle_states);
  85                 memcpy(dev->states, rk30_cpuidle_states, sizeof(rk30_cpuidle_states));
  86                 dev->safe_state = &dev->states[0];
  87
  88                 ret = cpuidle_register_device(dev);
  89                 if (ret) {
  90                         pr_err("failed to register cpuidle device for cpu %u: %d\n", cpu, ret);
  91                         return ret;
  92                 }
  93         }
  94
  95         return 0;
  96 }
  97 late_initcall(rk30_cpuidle_init);