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/cacheflush.h>
  13 #include <asm/cpuidle.h>
  14 #include <asm/suspend.h>
  15
  16 #include "common.h"
  17 #include "cpuidle.h"
  18 #include "hardware.h"
  19
  20 static int imx6sx_idle_finish(unsigned long val)
  21 {
  22         /*
  23          * for Cortex-A7 which has an internal L2
  24          * cache, need to flush it before powering
  25          * down ARM platform, since flushing L1 cache
  26          * here again has very small overhead, compared
  27          * to adding conditional code for L2 cache type,
  28          * just call flush_cache_all() is fine.
  29          */
  30         flush_cache_all();
  31         cpu_do_idle();
  32
  33         return 0;
  34 }
  35
  36 static int imx6sx_enter_wait(struct cpuidle_device *dev,
  37                             struct cpuidle_driver *drv, int index)
  38 {
  39         imx6_set_lpm(WAIT_UNCLOCKED);
  40
  41         switch (index) {
  42         case 1:
  43                 cpu_do_idle();
  44                 break;
  45         case 2:
  46                 imx6_enable_rbc(true);
  47                 imx_gpc_set_arm_power_in_lpm(true);
  48                 imx_set_cpu_jump(0, v7_cpu_resume);
  49                 /* Need to notify there is a cpu pm operation. */
  50                 cpu_pm_enter();
  51                 cpu_cluster_pm_enter();
  52
  53                 cpu_suspend(0, imx6sx_idle_finish);
  54
  55                 cpu_cluster_pm_exit();
  56                 cpu_pm_exit();
  57                 imx_gpc_set_arm_power_in_lpm(false);
  58                 imx6_enable_rbc(false);
  59                 break;
  60         default:
  61                 break;
  62         }
  63
  64         imx6_set_lpm(WAIT_CLOCKED);
  65
  66         return index;
  67 }
  68
  69 static struct cpuidle_driver imx6sx_cpuidle_driver = {
  70         .name = "imx6sx_cpuidle",
  71         .owner = THIS_MODULE,
  72         .states = {
  73                 /* WFI */
  74                 ARM_CPUIDLE_WFI_STATE,
  75                 /* WAIT */
  76                 {
  77                         .exit_latency = 50,
  78                         .target_residency = 75,
  79                         .flags = CPUIDLE_FLAG_TIMER_STOP,
  80                         .enter = imx6sx_enter_wait,
  81                         .name = "WAIT",
  82                         .desc = "Clock off",
  83                 },
  84                 /* WAIT + ARM power off  */
  85                 {
  86                         /*
  87                          * ARM gating 31us * 5 + RBC clear 65us
  88                          * and some margin for SW execution, here set it
  89                          * to 300us.
  90                          */
  91                         .exit_latency = 300,
  92                         .target_residency = 500,
  93                         .enter = imx6sx_enter_wait,
  94                         .name = "LOW-POWER-IDLE",
  95                         .desc = "ARM power off",
  96                 },
  97         },
  98         .state_count = 3,
  99         .safe_state_index = 0,
 100 };
 101
 102 int __init imx6sx_cpuidle_init(void)
 103 {
 104         imx6_set_int_mem_clk_lpm(true);
 105         imx6_enable_rbc(false);
 106         /*
 107          * set ARM power up/down timing to the fastest,
 108          * sw2iso and sw can be set to one 32K cycle = 31us
 109          * except for power up sw2iso which need to be
 110          * larger than LDO ramp up time.
 111          */
 112         imx_gpc_set_arm_power_up_timing(cpu_is_imx6sx() ? 0xf : 0x2, 1);
 113         imx_gpc_set_arm_power_down_timing(1, 1);
 114
 115         return cpuidle_register(&imx6sx_cpuidle_driver, NULL);
 116 }