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