arch/arm/mach-tegra/cpuidle-tegra20.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * CPU idle driver for Tegra CPUs
   4  *
   5  * Copyright (c) 2010-2012, NVIDIA Corporation.
   6  * Copyright (c) 2011 Google, Inc.
   7  * Author: Colin Cross <ccross@android.com>
   8  *         Gary King <gking@nvidia.com>
   9  *
  10  * Rework for 3.3 by Peter De Schrijver <pdeschrijver@nvidia.com>
  11  */
  12
  13 #include <linux/clk/tegra.h>
  14 #include <linux/tick.h>
  15 #include <linux/cpuidle.h>
  16 #include <linux/cpu_pm.h>
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19
  20 #include <soc/tegra/flowctrl.h>
  21
  22 #include <asm/cpuidle.h>
  23 #include <asm/smp_plat.h>
  24 #include <asm/suspend.h>
  25
  26 #include "cpuidle.h"
  27 #include "iomap.h"
  28 #include "irq.h"
  29 #include "pm.h"
  30 #include "reset.h"
  31 #include "sleep.h"
  32
  33 #ifdef CONFIG_PM_SLEEP
  34 static bool abort_flag;
  35 static atomic_t abort_barrier;
  36 static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
  37                                     struct cpuidle_driver *drv,
  38                                     int index);
  39 #define TEGRA20_MAX_STATES 2
  40 #else
  41 #define TEGRA20_MAX_STATES 1
  42 #endif
  43
  44 static struct cpuidle_driver tegra_idle_driver = {
  45         .name = "tegra_idle",
  46         .owner = THIS_MODULE,
  47         .states = {
  48                 ARM_CPUIDLE_WFI_STATE_PWR(600),
  49 #ifdef CONFIG_PM_SLEEP
  50                 {
  51                         .enter            = tegra20_idle_lp2_coupled,
  52                         .exit_latency     = 5000,
  53                         .target_residency = 10000,
  54                         .power_usage      = 0,
  55                         .flags            = CPUIDLE_FLAG_COUPLED |
  56                                             CPUIDLE_FLAG_TIMER_STOP,
  57                         .name             = "powered-down",
  58                         .desc             = "CPU power gated",
  59                 },
  60 #endif
  61         },
  62         .state_count = TEGRA20_MAX_STATES,
  63         .safe_state_index = 0,
  64 };
  65
  66 #ifdef CONFIG_PM_SLEEP
  67 #ifdef CONFIG_SMP
  68 static int tegra20_reset_sleeping_cpu_1(void)
  69 {
  70         int ret = 0;
  71
  72         tegra_pen_lock();
  73
  74         if (readb(tegra20_cpu1_resettable_status) == CPU_RESETTABLE)
  75                 tegra20_cpu_shutdown(1);
  76         else
  77                 ret = -EINVAL;
  78
  79         tegra_pen_unlock();
  80
  81         return ret;
  82 }
  83
  84 static void tegra20_wake_cpu1_from_reset(void)
  85 {
  86         tegra_pen_lock();
  87
  88         tegra20_cpu_clear_resettable();
  89
  90         /* enable cpu clock on cpu */
  91         tegra_enable_cpu_clock(1);
  92
  93         /* take the CPU out of reset */
  94         tegra_cpu_out_of_reset(1);
  95
  96         /* unhalt the cpu */
  97         flowctrl_write_cpu_halt(1, 0);
  98
  99         tegra_pen_unlock();
 100 }
 101
 102 static int tegra20_reset_cpu_1(void)
 103 {
 104         if (!cpu_online(1) || !tegra20_reset_sleeping_cpu_1())
 105                 return 0;
 106
 107         tegra20_wake_cpu1_from_reset();
 108         return -EBUSY;
 109 }
 110 #else
 111 static inline void tegra20_wake_cpu1_from_reset(void)
 112 {
 113 }
 114
 115 static inline int tegra20_reset_cpu_1(void)
 116 {
 117         return 0;
 118 }
 119 #endif
 120
 121 static bool tegra20_cpu_cluster_power_down(struct cpuidle_device *dev,
 122                                            struct cpuidle_driver *drv,
 123                                            int index)
 124 {
 125         while (tegra20_cpu_is_resettable_soon())
 126                 cpu_relax();
 127
 128         if (tegra20_reset_cpu_1() || !tegra_cpu_rail_off_ready())
 129                 return false;
 130
 131         tegra_idle_lp2_last();
 132
 133         if (cpu_online(1))
 134                 tegra20_wake_cpu1_from_reset();
 135
 136         return true;
 137 }
 138
 139 #ifdef CONFIG_SMP
 140 static bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev,
 141                                          struct cpuidle_driver *drv,
 142                                          int index)
 143 {
 144         cpu_suspend(0, tegra20_sleep_cpu_secondary_finish);
 145
 146         tegra20_cpu_clear_resettable();
 147
 148         return true;
 149 }
 150 #else
 151 static inline bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev,
 152                                                 struct cpuidle_driver *drv,
 153                                                 int index)
 154 {
 155         return true;
 156 }
 157 #endif
 158
 159 static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
 160                                     struct cpuidle_driver *drv,
 161                                     int index)
 162 {
 163         bool entered_lp2 = false;
 164
 165         if (tegra_pending_sgi())
 166                 WRITE_ONCE(abort_flag, true);
 167
 168         cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
 169
 170         if (abort_flag) {
 171                 cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
 172                 abort_flag = false;     /* clean flag for next coming */
 173                 return -EINTR;
 174         }
 175
 176         local_fiq_disable();
 177
 178         tegra_set_cpu_in_lp2();
 179         cpu_pm_enter();
 180
 181         if (dev->cpu == 0)
 182                 entered_lp2 = tegra20_cpu_cluster_power_down(dev, drv, index);
 183         else
 184                 entered_lp2 = tegra20_idle_enter_lp2_cpu_1(dev, drv, index);
 185
 186         cpu_pm_exit();
 187         tegra_clear_cpu_in_lp2();
 188
 189         local_fiq_enable();
 190
 191         smp_rmb();
 192
 193         return entered_lp2 ? index : 0;
 194 }
 195 #endif
 196
 197 /*
 198  * Tegra20 HW appears to have a bug such that PCIe device interrupts, whether
 199  * they are legacy IRQs or MSI, are lost when LP2 is enabled. To work around
 200  * this, simply disable LP2 if the PCI driver and DT node are both enabled.
 201  */
 202 void tegra20_cpuidle_pcie_irqs_in_use(void)
 203 {
 204         pr_info_once(
 205                 "Disabling cpuidle LP2 state, since PCIe IRQs are in use\n");
 206         cpuidle_driver_state_disabled(&tegra_idle_driver, 1, true);
 207 }
 208
 209 int __init tegra20_cpuidle_init(void)
 210 {
 211         return cpuidle_register(&tegra_idle_driver, cpu_possible_mask);
 212 }