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/context_tracking.h>
   7 #include <linux/cpuidle.h>
   8 #include <linux/module.h>
   9 #include <asm/cpuidle.h>
  10
  11 #include <soc/imx/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_RAW_SPINLOCK(cpuidle_lock);
  19
  20 static __cpuidle int imx6q_enter_wait(struct cpuidle_device *dev,
  21                                       struct cpuidle_driver *drv, int index)
  22 {
  23         raw_spin_lock(&cpuidle_lock);
  24         if (++num_idle_cpus == num_online_cpus())
  25                 imx6_set_lpm(WAIT_UNCLOCKED);
  26         raw_spin_unlock(&cpuidle_lock);
  27
  28         ct_cpuidle_enter();
  29         cpu_do_idle();
  30         ct_cpuidle_exit();
  31
  32         raw_spin_lock(&cpuidle_lock);
  33         if (num_idle_cpus-- == num_online_cpus())
  34                 imx6_set_lpm(WAIT_CLOCKED);
  35         raw_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 | CPUIDLE_FLAG_RCU_IDLE,
  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         cpuidle_driver_state_disabled(&imx6q_cpuidle_driver, 1, true);
  69 }
  70 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_used);
  71
  72 void imx6q_cpuidle_fec_irqs_unused(void)
  73 {
  74         cpuidle_driver_state_disabled(&imx6q_cpuidle_driver, 1, 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 }