arch/arm/mach-tegra/cpuidle-tegra20.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 <soc/tegra/flowctrl.h>
  30
  31 #include <asm/cpuidle.h>
  32 #include <asm/smp_plat.h>
  33 #include <asm/suspend.h>
  34
  35 #include "cpuidle.h"
  36 #include "iomap.h"
  37 #include "irq.h"
  38 #include "pm.h"
  39 #include "reset.h"
  40 #include "sleep.h"
  41
  42 #ifdef CONFIG_PM_SLEEP
  43 static bool abort_flag;
  44 static atomic_t abort_barrier;
  45 static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
  46                                     struct cpuidle_driver *drv,
  47                                     int index);
  48 #define TEGRA20_MAX_STATES 2
  49 #else
  50 #define TEGRA20_MAX_STATES 1
  51 #endif
  52
  53 static struct cpuidle_driver tegra_idle_driver = {
  54         .name = "tegra_idle",
  55         .owner = THIS_MODULE,
  56         .states = {
  57                 ARM_CPUIDLE_WFI_STATE_PWR(600),
  58 #ifdef CONFIG_PM_SLEEP
  59                 {
  60                         .enter            = tegra20_idle_lp2_coupled,
  61                         .exit_latency     = 5000,
  62                         .target_residency = 10000,
  63                         .power_usage      = 0,
  64                         .flags            = CPUIDLE_FLAG_COUPLED,
  65                         .name             = "powered-down",
  66                         .desc             = "CPU power gated",
  67                 },
  68 #endif
  69         },
  70         .state_count = TEGRA20_MAX_STATES,
  71         .safe_state_index = 0,
  72 };
  73
  74 #ifdef CONFIG_PM_SLEEP
  75 #ifdef CONFIG_SMP
  76 static int tegra20_reset_sleeping_cpu_1(void)
  77 {
  78         int ret = 0;
  79
  80         tegra_pen_lock();
  81
  82         if (readb(tegra20_cpu1_resettable_status) == CPU_RESETTABLE)
  83                 tegra20_cpu_shutdown(1);
  84         else
  85                 ret = -EINVAL;
  86
  87         tegra_pen_unlock();
  88
  89         return ret;
  90 }
  91
  92 static void tegra20_wake_cpu1_from_reset(void)
  93 {
  94         tegra_pen_lock();
  95
  96         tegra20_cpu_clear_resettable();
  97
  98         /* enable cpu clock on cpu */
  99         tegra_enable_cpu_clock(1);
 100
 101         /* take the CPU out of reset */
 102         tegra_cpu_out_of_reset(1);
 103
 104         /* unhalt the cpu */
 105         flowctrl_write_cpu_halt(1, 0);
 106
 107         tegra_pen_unlock();
 108 }
 109
 110 static int tegra20_reset_cpu_1(void)
 111 {
 112         if (!cpu_online(1) || !tegra20_reset_sleeping_cpu_1())
 113                 return 0;
 114
 115         tegra20_wake_cpu1_from_reset();
 116         return -EBUSY;
 117 }
 118 #else
 119 static inline void tegra20_wake_cpu1_from_reset(void)
 120 {
 121 }
 122
 123 static inline int tegra20_reset_cpu_1(void)
 124 {
 125         return 0;
 126 }
 127 #endif
 128
 129 static bool tegra20_cpu_cluster_power_down(struct cpuidle_device *dev,
 130                                            struct cpuidle_driver *drv,
 131                                            int index)
 132 {
 133         while (tegra20_cpu_is_resettable_soon())
 134                 cpu_relax();
 135
 136         if (tegra20_reset_cpu_1() || !tegra_cpu_rail_off_ready())
 137                 return false;
 138
 139         tick_broadcast_enter();
 140
 141         tegra_idle_lp2_last();
 142
 143         tick_broadcast_exit();
 144
 145         if (cpu_online(1))
 146                 tegra20_wake_cpu1_from_reset();
 147
 148         return true;
 149 }
 150
 151 #ifdef CONFIG_SMP
 152 static bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev,
 153                                          struct cpuidle_driver *drv,
 154                                          int index)
 155 {
 156         tick_broadcast_enter();
 157
 158         cpu_suspend(0, tegra20_sleep_cpu_secondary_finish);
 159
 160         tegra20_cpu_clear_resettable();
 161
 162         tick_broadcast_exit();
 163
 164         return true;
 165 }
 166 #else
 167 static inline bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev,
 168                                                 struct cpuidle_driver *drv,
 169                                                 int index)
 170 {
 171         return true;
 172 }
 173 #endif
 174
 175 static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
 176                                     struct cpuidle_driver *drv,
 177                                     int index)
 178 {
 179         bool entered_lp2 = false;
 180
 181         if (tegra_pending_sgi())
 182                 ACCESS_ONCE(abort_flag) = true;
 183
 184         cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
 185
 186         if (abort_flag) {
 187                 cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
 188                 abort_flag = false;     /* clean flag for next coming */
 189                 return -EINTR;
 190         }
 191
 192         local_fiq_disable();
 193
 194         tegra_set_cpu_in_lp2();
 195         cpu_pm_enter();
 196
 197         if (dev->cpu == 0)
 198                 entered_lp2 = tegra20_cpu_cluster_power_down(dev, drv, index);
 199         else
 200                 entered_lp2 = tegra20_idle_enter_lp2_cpu_1(dev, drv, index);
 201
 202         cpu_pm_exit();
 203         tegra_clear_cpu_in_lp2();
 204
 205         local_fiq_enable();
 206
 207         smp_rmb();
 208
 209         return entered_lp2 ? index : 0;
 210 }
 211 #endif
 212
 213 /*
 214  * Tegra20 HW appears to have a bug such that PCIe device interrupts, whether
 215  * they are legacy IRQs or MSI, are lost when LP2 is enabled. To work around
 216  * this, simply disable LP2 if the PCI driver and DT node are both enabled.
 217  */
 218 void tegra20_cpuidle_pcie_irqs_in_use(void)
 219 {
 220         pr_info_once(
 221                 "Disabling cpuidle LP2 state, since PCIe IRQs are in use\n");
 222         tegra_idle_driver.states[1].disabled = true;
 223 }
 224
 225 int __init tegra20_cpuidle_init(void)
 226 {
 227         return cpuidle_register(&tegra_idle_driver, cpu_possible_mask);
 228 }