kernel/arch/arm/mach-tegra/cpuidle-tegra30.c

   1 /*
   2  * CPU idle driver for Tegra CPUs
   3  *
   4  * Copyright (c) 2010-2012, NVIDIA Corporation.
   5  * Copyright (c) 2011 Google, Inc.
   6  * Author: Colin Cross <ccross@android.com>
   7  *         Gary King <gking@nvidia.com>
   8  *
   9  * Rework for 3.3 by Peter De Schrijver <pdeschrijver@nvidia.com>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful, but WITHOUT
  17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  18  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  19  * more details.
  20  */
  21
  22 #include <linux/clk/tegra.h>
  23 #include <linux/tick.h>
  24 #include <linux/cpuidle.h>
  25 #include <linux/cpu_pm.h>
  26 #include <linux/kernel.h>
  27 #include <linux/module.h>
  28
  29 #include <asm/cpuidle.h>
  30 #include <asm/smp_plat.h>
  31 #include <asm/suspend.h>
  32
  33 #include "pm.h"
  34 #include "sleep.h"
  35
  36 #ifdef CONFIG_PM_SLEEP
  37 static int tegra30_idle_lp2(struct cpuidle_device *dev,
  38                             struct cpuidle_driver *drv,
  39                             int index);
  40 #endif
  41
  42 static struct cpuidle_driver tegra_idle_driver = {
  43         .name = "tegra_idle",
  44         .owner = THIS_MODULE,
  45 #ifdef CONFIG_PM_SLEEP
  46         .state_count = 2,
  47 #else
  48         .state_count = 1,
  49 #endif
  50         .states = {
  51                 [0] = ARM_CPUIDLE_WFI_STATE_PWR(600),
  52 #ifdef CONFIG_PM_SLEEP
  53                 [1] = {
  54                         .enter                  = tegra30_idle_lp2,
  55                         .exit_latency           = 2000,
  56                         .target_residency       = 2200,
  57                         .power_usage            = 0,
  58                         .name                   = "powered-down",
  59                         .desc                   = "CPU power gated",
  60                 },
  61 #endif
  62         },
  63 };
  64
  65 #ifdef CONFIG_PM_SLEEP
  66 static bool tegra30_cpu_cluster_power_down(struct cpuidle_device *dev,
  67                                            struct cpuidle_driver *drv,
  68                                            int index)
  69 {
  70         /* All CPUs entering LP2 is not working.
  71          * Don't let CPU0 enter LP2 when any secondary CPU is online.
  72          */
  73         if (num_online_cpus() > 1 || !tegra_cpu_rail_off_ready()) {
  74                 cpu_do_idle();
  75                 return false;
  76         }
  77
  78         tick_broadcast_enter();
  79
  80         tegra_idle_lp2_last();
  81
  82         tick_broadcast_exit();
  83
  84         return true;
  85 }
  86
  87 #ifdef CONFIG_SMP
  88 static bool tegra30_cpu_core_power_down(struct cpuidle_device *dev,
  89                                         struct cpuidle_driver *drv,
  90                                         int index)
  91 {
  92         tick_broadcast_enter();
  93
  94         smp_wmb();
  95
  96         cpu_suspend(0, tegra30_sleep_cpu_secondary_finish);
  97
  98         tick_broadcast_exit();
  99
 100         return true;
 101 }
 102 #else
 103 static inline bool tegra30_cpu_core_power_down(struct cpuidle_device *dev,
 104                                                struct cpuidle_driver *drv,
 105                                                int index)
 106 {
 107         return true;
 108 }
 109 #endif
 110
 111 static int tegra30_idle_lp2(struct cpuidle_device *dev,
 112                             struct cpuidle_driver *drv,
 113                             int index)
 114 {
 115         bool entered_lp2 = false;
 116         bool last_cpu;
 117
 118         local_fiq_disable();
 119
 120         last_cpu = tegra_set_cpu_in_lp2();
 121         cpu_pm_enter();
 122
 123         if (dev->cpu == 0) {
 124                 if (last_cpu)
 125                         entered_lp2 = tegra30_cpu_cluster_power_down(dev, drv,
 126                                                                      index);
 127                 else
 128                         cpu_do_idle();
 129         } else {
 130                 entered_lp2 = tegra30_cpu_core_power_down(dev, drv, index);
 131         }
 132
 133         cpu_pm_exit();
 134         tegra_clear_cpu_in_lp2();
 135
 136         local_fiq_enable();
 137
 138         smp_rmb();
 139
 140         return (entered_lp2) ? index : 0;
 141 }
 142 #endif
 143
 144 int __init tegra30_cpuidle_init(void)
 145 {
 146         return cpuidle_register(&tegra_idle_driver, NULL);
 147 }