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         rcu_idle_enter();
  28         cpu_do_idle();
  29         rcu_idle_exit();
  30
  31         raw_spin_lock(&cpuidle_lock);
  32         if (num_idle_cpus-- == num_online_cpus())
  33                 imx6_set_lpm(WAIT_CLOCKED);
  34         raw_spin_unlock(&cpuidle_lock);
  35
  36         return index;
  37 }
  38
  39 static struct cpuidle_driver imx6q_cpuidle_driver = {
  40         .name = "imx6q_cpuidle",
  41         .owner = THIS_MODULE,
  42         .states = {
  43                 /* WFI */
  44                 ARM_CPUIDLE_WFI_STATE,
  45                 /* WAIT */
  46                 {
  47                         .exit_latency = 50,
  48                         .target_residency = 75,
  49                         .flags = CPUIDLE_FLAG_TIMER_STOP | CPUIDLE_FLAG_RCU_IDLE,
  50                         .enter = imx6q_enter_wait,
  51                         .name = "WAIT",
  52                         .desc = "Clock off",
  53                 },
  54         },
  55         .state_count = 2,
  56         .safe_state_index = 0,
  57 };
  58
  59 /*
  60  * i.MX6 Q/DL has an erratum (ERR006687) that prevents the FEC from waking the
  61  * CPUs when they are in wait(unclocked) state. As the hardware workaround isn't
  62  * applicable to all boards, disable the deeper idle state when the workaround
  63  * isn't present and the FEC is in use.
  64  */
  65 void imx6q_cpuidle_fec_irqs_used(void)
  66 {
  67         cpuidle_driver_state_disabled(&imx6q_cpuidle_driver, 1, true);
  68 }
  69 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_used);
  70
  71 void imx6q_cpuidle_fec_irqs_unused(void)
  72 {
  73         cpuidle_driver_state_disabled(&imx6q_cpuidle_driver, 1, false);
  74 }
  75 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_unused);
  76
  77 int __init imx6q_cpuidle_init(void)
  78 {
  79         /* Set INT_MEM_CLK_LPM bit to get a reliable WAIT mode support */
  80         imx6_set_int_mem_clk_lpm(true);
  81
  82         return cpuidle_register(&imx6q_cpuidle_driver, NULL);
  83 }