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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012 Freescale Semiconductor, Inc.
   4  */
   5
   6 #include <linux/cpuidle.h>
   7 #include <linux/module.h>
   8 #include <asm/cpuidle.h>
   9
  10 #include <soc/imx/cpuidle.h>
  11
  12 #include "common.h"
  13 #include "cpuidle.h"
  14 #include "hardware.h"
  15
  16 static int num_idle_cpus = 0;
  17 static DEFINE_RAW_SPINLOCK(cpuidle_lock);
  18
  19 static int imx6q_enter_wait(struct cpuidle_device *dev,
  20                             struct cpuidle_driver *drv, int index)
  21 {
  22         raw_spin_lock(&cpuidle_lock);
  23         if (++num_idle_cpus == num_online_cpus())
  24                 imx6_set_lpm(WAIT_UNCLOCKED);
  25         raw_spin_unlock(&cpuidle_lock);
  26
  27         cpu_do_idle();
  28
  29         raw_spin_lock(&cpuidle_lock);
  30         if (num_idle_cpus-- == num_online_cpus())
  31                 imx6_set_lpm(WAIT_CLOCKED);
  32         raw_spin_unlock(&cpuidle_lock);
  33
  34         return index;
  35 }
  36
  37 static struct cpuidle_driver imx6q_cpuidle_driver = {
  38         .name = "imx6q_cpuidle",
  39         .owner = THIS_MODULE,
  40         .states = {
  41                 /* WFI */
  42                 ARM_CPUIDLE_WFI_STATE,
  43                 /* WAIT */
  44                 {
  45                         .exit_latency = 50,
  46                         .target_residency = 75,
  47                         .flags = CPUIDLE_FLAG_TIMER_STOP,
  48                         .enter = imx6q_enter_wait,
  49                         .name = "WAIT",
  50                         .desc = "Clock off",
  51                 },
  52         },
  53         .state_count = 2,
  54         .safe_state_index = 0,
  55 };
  56
  57 /*
  58  * i.MX6 Q/DL has an erratum (ERR006687) that prevents the FEC from waking the
  59  * CPUs when they are in wait(unclocked) state. As the hardware workaround isn't
  60  * applicable to all boards, disable the deeper idle state when the workaround
  61  * isn't present and the FEC is in use.
  62  */
  63 void imx6q_cpuidle_fec_irqs_used(void)
  64 {
  65         cpuidle_driver_state_disabled(&imx6q_cpuidle_driver, 1, true);
  66 }
  67 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_used);
  68
  69 void imx6q_cpuidle_fec_irqs_unused(void)
  70 {
  71         cpuidle_driver_state_disabled(&imx6q_cpuidle_driver, 1, false);
  72 }
  73 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_unused);
  74
  75 int __init imx6q_cpuidle_init(void)
  76 {
  77         /* Set INT_MEM_CLK_LPM bit to get a reliable WAIT mode support */
  78         imx6_set_int_mem_clk_lpm(true);
  79
  80         return cpuidle_register(&imx6q_cpuidle_driver, NULL);
  81 }