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/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/cpuidle.h>
  25 #include <linux/cpu_pm.h>
  26 #include <linux/clockchips.h>
  27 #include <linux/clk/tegra.h>
  28
  29 #include <asm/cpuidle.h>
  30 #include <asm/proc-fns.h>
  31 #include <asm/suspend.h>
  32 #include <asm/smp_plat.h>
  33
  34 #include "pm.h"
  35 #include "sleep.h"
  36 #include "iomap.h"
  37 #include "irq.h"
  38 #include "flowctrl.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_TIME_VALID |
  63                         CPUIDLE_FLAG_COUPLED,
  64                         .name             = "powered-down",
  65                         .desc             = "CPU power gated",
  66                 },
  67 #endif
  68         },
  69         .state_count = TEGRA20_MAX_STATES,
  70         .safe_state_index = 0,
  71 };
  72
  73 #ifdef CONFIG_PM_SLEEP
  74 #ifdef CONFIG_SMP
  75 static void __iomem *pmc = IO_ADDRESS(TEGRA_PMC_BASE);
  76
  77 static int tegra20_reset_sleeping_cpu_1(void)
  78 {
  79         int ret = 0;
  80
  81         tegra_pen_lock();
  82
  83         if (readl(pmc + PMC_SCRATCH41) == CPU_RESETTABLE)
  84                 tegra20_cpu_shutdown(1);
  85         else
  86                 ret = -EINVAL;
  87
  88         tegra_pen_unlock();
  89
  90         return ret;
  91 }
  92
  93 static void tegra20_wake_cpu1_from_reset(void)
  94 {
  95         tegra_pen_lock();
  96
  97         tegra20_cpu_clear_resettable();
  98
  99         /* enable cpu clock on cpu */
 100         tegra_enable_cpu_clock(1);
 101
 102         /* take the CPU out of reset */
 103         tegra_cpu_out_of_reset(1);
 104
 105         /* unhalt the cpu */
 106         flowctrl_write_cpu_halt(1, 0);
 107
 108         tegra_pen_unlock();
 109 }
 110
 111 static int tegra20_reset_cpu_1(void)
 112 {
 113         if (!cpu_online(1) || !tegra20_reset_sleeping_cpu_1())
 114                 return 0;
 115
 116         tegra20_wake_cpu1_from_reset();
 117         return -EBUSY;
 118 }
 119 #else
 120 static inline void tegra20_wake_cpu1_from_reset(void)
 121 {
 122 }
 123
 124 static inline int tegra20_reset_cpu_1(void)
 125 {
 126         return 0;
 127 }
 128 #endif
 129
 130 static bool tegra20_cpu_cluster_power_down(struct cpuidle_device *dev,
 131                                            struct cpuidle_driver *drv,
 132                                            int index)
 133 {
 134         struct cpuidle_state *state = &drv->states[index];
 135         u32 cpu_on_time = state->exit_latency;
 136         u32 cpu_off_time = state->target_residency - state->exit_latency;
 137
 138         while (tegra20_cpu_is_resettable_soon())
 139                 cpu_relax();
 140
 141         if (tegra20_reset_cpu_1() || !tegra_cpu_rail_off_ready())
 142                 return false;
 143
 144         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu);
 145
 146         tegra_idle_lp2_last(cpu_on_time, cpu_off_time);
 147
 148         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);
 149
 150         if (cpu_online(1))
 151                 tegra20_wake_cpu1_from_reset();
 152
 153         return true;
 154 }
 155
 156 #ifdef CONFIG_SMP
 157 static bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev,
 158                                          struct cpuidle_driver *drv,
 159                                          int index)
 160 {
 161         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu);
 162
 163         cpu_suspend(0, tegra20_sleep_cpu_secondary_finish);
 164
 165         tegra20_cpu_clear_resettable();
 166
 167         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);
 168
 169         return true;
 170 }
 171 #else
 172 static inline bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev,
 173                                                 struct cpuidle_driver *drv,
 174                                                 int index)
 175 {
 176         return true;
 177 }
 178 #endif
 179
 180 static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
 181                                     struct cpuidle_driver *drv,
 182                                     int index)
 183 {
 184         u32 cpu = is_smp() ? cpu_logical_map(dev->cpu) : dev->cpu;
 185         bool entered_lp2 = false;
 186
 187         if (tegra_pending_sgi())
 188                 ACCESS_ONCE(abort_flag) = true;
 189
 190         cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
 191
 192         if (abort_flag) {
 193                 cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
 194                 abort_flag = false;     /* clean flag for next coming */
 195                 return -EINTR;
 196         }
 197
 198         local_fiq_disable();
 199
 200         tegra_set_cpu_in_lp2(cpu);
 201         cpu_pm_enter();
 202
 203         if (cpu == 0)
 204                 entered_lp2 = tegra20_cpu_cluster_power_down(dev, drv, index);
 205         else
 206                 entered_lp2 = tegra20_idle_enter_lp2_cpu_1(dev, drv, index);
 207
 208         cpu_pm_exit();
 209         tegra_clear_cpu_in_lp2(cpu);
 210
 211         local_fiq_enable();
 212
 213         smp_rmb();
 214
 215         return entered_lp2 ? index : 0;
 216 }
 217 #endif
 218
 219 int __init tegra20_cpuidle_init(void)
 220 {
 221 #ifdef CONFIG_PM_SLEEP
 222         tegra_tear_down_cpu = tegra20_tear_down_cpu;
 223 #endif
 224         return cpuidle_register(&tegra_idle_driver, cpu_possible_mask);
 225 }