arch/arm/mach-imx/cpuidle-imx6sx.c

   1 /*
   2  * Copyright (C) 2014 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/cpu_pm.h>
  11 #include <linux/module.h>
  12 #include <asm/cpuidle.h>
  13 #include <asm/proc-fns.h>
  14 #include <asm/suspend.h>
  15
  16 #include "common.h"
  17 #include "cpuidle.h"
  18
  19 static int imx6sx_idle_finish(unsigned long val)
  20 {
  21         cpu_do_idle();
  22
  23         return 0;
  24 }
  25
  26 static int imx6sx_enter_wait(struct cpuidle_device *dev,
  27                             struct cpuidle_driver *drv, int index)
  28 {
  29         imx6q_set_lpm(WAIT_UNCLOCKED);
  30
  31         switch (index) {
  32         case 1:
  33                 cpu_do_idle();
  34                 break;
  35         case 2:
  36                 imx6_enable_rbc(true);
  37                 imx_gpc_set_arm_power_in_lpm(true);
  38                 imx_set_cpu_jump(0, v7_cpu_resume);
  39                 /* Need to notify there is a cpu pm operation. */
  40                 cpu_pm_enter();
  41                 cpu_cluster_pm_enter();
  42
  43                 cpu_suspend(0, imx6sx_idle_finish);
  44
  45                 cpu_cluster_pm_exit();
  46                 cpu_pm_exit();
  47                 imx_gpc_set_arm_power_in_lpm(false);
  48                 imx6_enable_rbc(false);
  49                 break;
  50         default:
  51                 break;
  52         }
  53
  54         imx6q_set_lpm(WAIT_CLOCKED);
  55
  56         return index;
  57 }
  58
  59 static struct cpuidle_driver imx6sx_cpuidle_driver = {
  60         .name = "imx6sx_cpuidle",
  61         .owner = THIS_MODULE,
  62         .states = {
  63                 /* WFI */
  64                 ARM_CPUIDLE_WFI_STATE,
  65                 /* WAIT */
  66                 {
  67                         .exit_latency = 50,
  68                         .target_residency = 75,
  69                         .flags = CPUIDLE_FLAG_TIMER_STOP,
  70                         .enter = imx6sx_enter_wait,
  71                         .name = "WAIT",
  72                         .desc = "Clock off",
  73                 },
  74                 /* WAIT + ARM power off  */
  75                 {
  76                         /*
  77                          * ARM gating 31us * 5 + RBC clear 65us
  78                          * and some margin for SW execution, here set it
  79                          * to 300us.
  80                          */
  81                         .exit_latency = 300,
  82                         .target_residency = 500,
  83                         .enter = imx6sx_enter_wait,
  84                         .name = "LOW-POWER-IDLE",
  85                         .desc = "ARM power off",
  86                 },
  87         },
  88         .state_count = 3,
  89         .safe_state_index = 0,
  90 };
  91
  92 int __init imx6sx_cpuidle_init(void)
  93 {
  94         imx6_enable_rbc(false);
  95         /*
  96          * set ARM power up/down timing to the fastest,
  97          * sw2iso and sw can be set to one 32K cycle = 31us
  98          * except for power up sw2iso which need to be
  99          * larger than LDO ramp up time.
 100          */
 101         imx_gpc_set_arm_power_up_timing(2, 1);
 102         imx_gpc_set_arm_power_down_timing(1, 1);
 103
 104         return cpuidle_register(&imx6sx_cpuidle_driver, NULL);
 105 }