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 <soc/imx/cpuidle.h>
  14
  15 #include "common.h"
  16 #include "cpuidle.h"
  17 #include "hardware.h"
  18
  19 static int num_idle_cpus = 0;
  20 static DEFINE_SPINLOCK(cpuidle_lock);
  21
  22 static int imx6q_enter_wait(struct cpuidle_device *dev,
  23                             struct cpuidle_driver *drv, int index)
  24 {
  25         spin_lock(&cpuidle_lock);
  26         if (++num_idle_cpus == num_online_cpus())
  27                 imx6_set_lpm(WAIT_UNCLOCKED);
  28         spin_unlock(&cpuidle_lock);
  29
  30         cpu_do_idle();
  31
  32         spin_lock(&cpuidle_lock);
  33         if (num_idle_cpus-- == num_online_cpus())
  34                 imx6_set_lpm(WAIT_CLOCKED);
  35         spin_unlock(&cpuidle_lock);
  36
  37         return index;
  38 }
  39
  40 static struct cpuidle_driver imx6q_cpuidle_driver = {
  41         .name = "imx6q_cpuidle",
  42         .owner = THIS_MODULE,
  43         .states = {
  44                 /* WFI */
  45                 ARM_CPUIDLE_WFI_STATE,
  46                 /* WAIT */
  47                 {
  48                         .exit_latency = 50,
  49                         .target_residency = 75,
  50                         .flags = CPUIDLE_FLAG_TIMER_STOP,
  51                         .enter = imx6q_enter_wait,
  52                         .name = "WAIT",
  53                         .desc = "Clock off",
  54                 },
  55         },
  56         .state_count = 2,
  57         .safe_state_index = 0,
  58 };
  59
  60 /*
  61  * i.MX6 Q/DL has an erratum (ERR006687) that prevents the FEC from waking the
  62  * CPUs when they are in wait(unclocked) state. As the hardware workaround isn't
  63  * applicable to all boards, disable the deeper idle state when the workaround
  64  * isn't present and the FEC is in use.
  65  */
  66 void imx6q_cpuidle_fec_irqs_used(void)
  67 {
  68         imx6q_cpuidle_driver.states[1].disabled = true;
  69 }
  70 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_used);
  71
  72 void imx6q_cpuidle_fec_irqs_unused(void)
  73 {
  74         imx6q_cpuidle_driver.states[1].disabled = false;
  75 }
  76 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_unused);
  77
  78 int __init imx6q_cpuidle_init(void)
  79 {
  80         /* Set INT_MEM_CLK_LPM bit to get a reliable WAIT mode support */
  81         imx6_set_int_mem_clk_lpm(true);
  82
  83         return cpuidle_register(&imx6q_cpuidle_driver, NULL);
  84 }