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/suspend.h>
  14
  15 #include "common.h"
  16 #include "cpuidle.h"
  17
  18 static int imx6sx_idle_finish(unsigned long val)
  19 {
  20         cpu_do_idle();
  21
  22         return 0;
  23 }
  24
  25 static int imx6sx_enter_wait(struct cpuidle_device *dev,
  26                             struct cpuidle_driver *drv, int index)
  27 {
  28         imx6_set_lpm(WAIT_UNCLOCKED);
  29
  30         switch (index) {
  31         case 1:
  32                 cpu_do_idle();
  33                 break;
  34         case 2:
  35                 imx6_enable_rbc(true);
  36                 imx_gpc_set_arm_power_in_lpm(true);
  37                 imx_set_cpu_jump(0, v7_cpu_resume);
  38                 /* Need to notify there is a cpu pm operation. */
  39                 cpu_pm_enter();
  40                 cpu_cluster_pm_enter();
  41
  42                 cpu_suspend(0, imx6sx_idle_finish);
  43
  44                 cpu_cluster_pm_exit();
  45                 cpu_pm_exit();
  46                 imx_gpc_set_arm_power_in_lpm(false);
  47                 imx6_enable_rbc(false);
  48                 break;
  49         default:
  50                 break;
  51         }
  52
  53         imx6_set_lpm(WAIT_CLOCKED);
  54
  55         return index;
  56 }
  57
  58 static struct cpuidle_driver imx6sx_cpuidle_driver = {
  59         .name = "imx6sx_cpuidle",
  60         .owner = THIS_MODULE,
  61         .states = {
  62                 /* WFI */
  63                 ARM_CPUIDLE_WFI_STATE,
  64                 /* WAIT */
  65                 {
  66                         .exit_latency = 50,
  67                         .target_residency = 75,
  68                         .flags = CPUIDLE_FLAG_TIMER_STOP,
  69                         .enter = imx6sx_enter_wait,
  70                         .name = "WAIT",
  71                         .desc = "Clock off",
  72                 },
  73                 /* WAIT + ARM power off  */
  74                 {
  75                         /*
  76                          * ARM gating 31us * 5 + RBC clear 65us
  77                          * and some margin for SW execution, here set it
  78                          * to 300us.
  79                          */
  80                         .exit_latency = 300,
  81                         .target_residency = 500,
  82                         .enter = imx6sx_enter_wait,
  83                         .name = "LOW-POWER-IDLE",
  84                         .desc = "ARM power off",
  85                 },
  86         },
  87         .state_count = 3,
  88         .safe_state_index = 0,
  89 };
  90
  91 int __init imx6sx_cpuidle_init(void)
  92 {
  93         imx6_enable_rbc(false);
  94         /*
  95          * set ARM power up/down timing to the fastest,
  96          * sw2iso and sw can be set to one 32K cycle = 31us
  97          * except for power up sw2iso which need to be
  98          * larger than LDO ramp up time.
  99          */
 100         imx_gpc_set_arm_power_up_timing(2, 1);
 101         imx_gpc_set_arm_power_down_timing(1, 1);
 102
 103         return cpuidle_register(&imx6sx_cpuidle_driver, NULL);
 104 }