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 "cpuidle.h"
  34 #include "pm.h"
  35 #include "sleep.h"
  36
  37 #ifdef CONFIG_PM_SLEEP
  38 static int tegra30_idle_lp2(struct cpuidle_device *dev,
  39                             struct cpuidle_driver *drv,
  40                             int index);
  41 #endif
  42
  43 static struct cpuidle_driver tegra_idle_driver = {
  44         .name = "tegra_idle",
  45         .owner = THIS_MODULE,
  46 #ifdef CONFIG_PM_SLEEP
  47         .state_count = 2,
  48 #else
  49         .state_count = 1,
  50 #endif
  51         .states = {
  52                 [0] = ARM_CPUIDLE_WFI_STATE_PWR(600),
  53 #ifdef CONFIG_PM_SLEEP
  54                 [1] = {
  55                         .enter                  = tegra30_idle_lp2,
  56                         .exit_latency           = 2000,
  57                         .target_residency       = 2200,
  58                         .power_usage            = 0,
  59                         .name                   = "powered-down",
  60                         .desc                   = "CPU power gated",
  61                 },
  62 #endif
  63         },
  64 };
  65
  66 #ifdef CONFIG_PM_SLEEP
  67 static bool tegra30_cpu_cluster_power_down(struct cpuidle_device *dev,
  68                                            struct cpuidle_driver *drv,
  69                                            int index)
  70 {
  71         /* All CPUs entering LP2 is not working.
  72          * Don't let CPU0 enter LP2 when any secondary CPU is online.
  73          */
  74         if (num_online_cpus() > 1 || !tegra_cpu_rail_off_ready()) {
  75                 cpu_do_idle();
  76                 return false;
  77         }
  78
  79         tick_broadcast_enter();
  80
  81         tegra_idle_lp2_last();
  82
  83         tick_broadcast_exit();
  84
  85         return true;
  86 }
  87
  88 #ifdef CONFIG_SMP
  89 static bool tegra30_cpu_core_power_down(struct cpuidle_device *dev,
  90                                         struct cpuidle_driver *drv,
  91                                         int index)
  92 {
  93         tick_broadcast_enter();
  94
  95         smp_wmb();
  96
  97         cpu_suspend(0, tegra30_sleep_cpu_secondary_finish);
  98
  99         tick_broadcast_exit();
 100
 101         return true;
 102 }
 103 #else
 104 static inline bool tegra30_cpu_core_power_down(struct cpuidle_device *dev,
 105                                                struct cpuidle_driver *drv,
 106                                                int index)
 107 {
 108         return true;
 109 }
 110 #endif
 111
 112 static int tegra30_idle_lp2(struct cpuidle_device *dev,
 113                             struct cpuidle_driver *drv,
 114                             int index)
 115 {
 116         bool entered_lp2 = false;
 117         bool last_cpu;
 118
 119         local_fiq_disable();
 120
 121         last_cpu = tegra_set_cpu_in_lp2();
 122         cpu_pm_enter();
 123
 124         if (dev->cpu == 0) {
 125                 if (last_cpu)
 126                         entered_lp2 = tegra30_cpu_cluster_power_down(dev, drv,
 127                                                                      index);
 128                 else
 129                         cpu_do_idle();
 130         } else {
 131                 entered_lp2 = tegra30_cpu_core_power_down(dev, drv, index);
 132         }
 133
 134         cpu_pm_exit();
 135         tegra_clear_cpu_in_lp2();
 136
 137         local_fiq_enable();
 138
 139         smp_rmb();
 140
 141         return (entered_lp2) ? index : 0;
 142 }
 143 #endif
 144
 145 int __init tegra30_cpuidle_init(void)
 146 {
 147         return cpuidle_register(&tegra_idle_driver, NULL);
 148 }