arch/arm/mach-omap2/cpuidle44xx.c

   1 /*
   2  * OMAP4+ CPU idle Routines
   3  *
   4  * Copyright (C) 2011-2013 Texas Instruments, Inc.
   5  * Santosh Shilimkar <santosh.shilimkar@ti.com>
   6  * Rajendra Nayak <rnayak@ti.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/sched.h>
  14 #include <linux/cpuidle.h>
  15 #include <linux/cpu_pm.h>
  16 #include <linux/export.h>
  17
  18 #include <asm/cpuidle.h>
  19 #include <asm/proc-fns.h>
  20
  21 #include "common.h"
  22 #include "pm.h"
  23 #include "prm.h"
  24 #include "clockdomain.h"
  25
  26 #define MAX_CPUS        2
  27
  28 /* Machine specific information */
  29 struct idle_statedata {
  30         u32 cpu_state;
  31         u32 mpu_logic_state;
  32         u32 mpu_state;
  33 };
  34
  35 static struct idle_statedata omap4_idle_data[] = {
  36         {
  37                 .cpu_state = PWRDM_POWER_ON,
  38                 .mpu_state = PWRDM_POWER_ON,
  39                 .mpu_logic_state = PWRDM_POWER_RET,
  40         },
  41         {
  42                 .cpu_state = PWRDM_POWER_OFF,
  43                 .mpu_state = PWRDM_POWER_RET,
  44                 .mpu_logic_state = PWRDM_POWER_RET,
  45         },
  46         {
  47                 .cpu_state = PWRDM_POWER_OFF,
  48                 .mpu_state = PWRDM_POWER_RET,
  49                 .mpu_logic_state = PWRDM_POWER_OFF,
  50         },
  51 };
  52
  53 static struct powerdomain *mpu_pd, *cpu_pd[MAX_CPUS];
  54 static struct clockdomain *cpu_clkdm[MAX_CPUS];
  55
  56 static atomic_t abort_barrier;
  57 static bool cpu_done[MAX_CPUS];
  58 static struct idle_statedata *state_ptr = &omap4_idle_data[0];
  59
  60 /* Private functions */
  61
  62 /**
  63  * omap_enter_idle_[simple/coupled] - OMAP4PLUS cpuidle entry functions
  64  * @dev: cpuidle device
  65  * @drv: cpuidle driver
  66  * @index: the index of state to be entered
  67  *
  68  * Called from the CPUidle framework to program the device to the
  69  * specified low power state selected by the governor.
  70  * Returns the amount of time spent in the low power state.
  71  */
  72 static int omap_enter_idle_simple(struct cpuidle_device *dev,
  73                         struct cpuidle_driver *drv,
  74                         int index)
  75 {
  76         omap_do_wfi();
  77         return index;
  78 }
  79
  80 static int omap_enter_idle_coupled(struct cpuidle_device *dev,
  81                         struct cpuidle_driver *drv,
  82                         int index)
  83 {
  84         struct idle_statedata *cx = state_ptr + index;
  85         u32 mpuss_can_lose_context = 0;
  86
  87         /*
  88          * CPU0 has to wait and stay ON until CPU1 is OFF state.
  89          * This is necessary to honour hardware recommondation
  90          * of triggeing all the possible low power modes once CPU1 is
  91          * out of coherency and in OFF mode.
  92          */
  93         if (dev->cpu == 0 && cpumask_test_cpu(1, cpu_online_mask)) {
  94                 while (pwrdm_read_pwrst(cpu_pd[1]) != PWRDM_POWER_OFF) {
  95                         cpu_relax();
  96
  97                         /*
  98                          * CPU1 could have already entered & exited idle
  99                          * without hitting off because of a wakeup
 100                          * or a failed attempt to hit off mode.  Check for
 101                          * that here, otherwise we could spin forever
 102                          * waiting for CPU1 off.
 103                          */
 104                         if (cpu_done[1])
 105                             goto fail;
 106
 107                 }
 108         }
 109
 110         mpuss_can_lose_context = (cx->mpu_state == PWRDM_POWER_RET) &&
 111                                  (cx->mpu_logic_state == PWRDM_POWER_OFF);
 112
 113         /*
 114          * Call idle CPU PM enter notifier chain so that
 115          * VFP and per CPU interrupt context is saved.
 116          */
 117         cpu_pm_enter();
 118
 119         if (dev->cpu == 0) {
 120                 pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state);
 121                 omap_set_pwrdm_state(mpu_pd, cx->mpu_state);
 122
 123                 /*
 124                  * Call idle CPU cluster PM enter notifier chain
 125                  * to save GIC and wakeupgen context.
 126                  */
 127                 if (mpuss_can_lose_context)
 128                         cpu_cluster_pm_enter();
 129         }
 130
 131         omap4_enter_lowpower(dev->cpu, cx->cpu_state);
 132         cpu_done[dev->cpu] = true;
 133
 134         /* Wakeup CPU1 only if it is not offlined */
 135         if (dev->cpu == 0 && cpumask_test_cpu(1, cpu_online_mask)) {
 136
 137                 if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) &&
 138                     mpuss_can_lose_context)
 139                         gic_dist_disable();
 140
 141                 clkdm_wakeup(cpu_clkdm[1]);
 142                 omap_set_pwrdm_state(cpu_pd[1], PWRDM_POWER_ON);
 143                 clkdm_allow_idle(cpu_clkdm[1]);
 144
 145                 if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) &&
 146                     mpuss_can_lose_context) {
 147                         while (gic_dist_disabled()) {
 148                                 udelay(1);
 149                                 cpu_relax();
 150                         }
 151                         gic_timer_retrigger();
 152                 }
 153         }
 154
 155         /*
 156          * Call idle CPU PM exit notifier chain to restore
 157          * VFP and per CPU IRQ context.
 158          */
 159         cpu_pm_exit();
 160
 161         /*
 162          * Call idle CPU cluster PM exit notifier chain
 163          * to restore GIC and wakeupgen context.
 164          */
 165         if (dev->cpu == 0 && mpuss_can_lose_context)
 166                 cpu_cluster_pm_exit();
 167
 168 fail:
 169         cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
 170         cpu_done[dev->cpu] = false;
 171
 172         return index;
 173 }
 174
 175 static struct cpuidle_driver omap4_idle_driver = {
 176         .name                           = "omap4_idle",
 177         .owner                          = THIS_MODULE,
 178         .states = {
 179                 {
 180                         /* C1 - CPU0 ON + CPU1 ON + MPU ON */
 181                         .exit_latency = 2 + 2,
 182                         .target_residency = 5,
 183                         .flags = CPUIDLE_FLAG_TIME_VALID,
 184                         .enter = omap_enter_idle_simple,
 185                         .name = "C1",
 186                         .desc = "CPUx ON, MPUSS ON"
 187                 },
 188                 {
 189                         /* C2 - CPU0 OFF + CPU1 OFF + MPU CSWR */
 190                         .exit_latency = 328 + 440,
 191                         .target_residency = 960,
 192                         .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_COUPLED |
 193                                  CPUIDLE_FLAG_TIMER_STOP,
 194                         .enter = omap_enter_idle_coupled,
 195                         .name = "C2",
 196                         .desc = "CPUx OFF, MPUSS CSWR",
 197                 },
 198                 {
 199                         /* C3 - CPU0 OFF + CPU1 OFF + MPU OSWR */
 200                         .exit_latency = 460 + 518,
 201                         .target_residency = 1100,
 202                         .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_COUPLED |
 203                                  CPUIDLE_FLAG_TIMER_STOP,
 204                         .enter = omap_enter_idle_coupled,
 205                         .name = "C3",
 206                         .desc = "CPUx OFF, MPUSS OSWR",
 207                 },
 208         },
 209         .state_count = ARRAY_SIZE(omap4_idle_data),
 210         .safe_state_index = 0,
 211 };
 212
 213 /* Public functions */
 214
 215 /**
 216  * omap4_idle_init - Init routine for OMAP4+ idle
 217  *
 218  * Registers the OMAP4+ specific cpuidle driver to the cpuidle
 219  * framework with the valid set of states.
 220  */
 221 int __init omap4_idle_init(void)
 222 {
 223         mpu_pd = pwrdm_lookup("mpu_pwrdm");
 224         cpu_pd[0] = pwrdm_lookup("cpu0_pwrdm");
 225         cpu_pd[1] = pwrdm_lookup("cpu1_pwrdm");
 226         if ((!mpu_pd) || (!cpu_pd[0]) || (!cpu_pd[1]))
 227                 return -ENODEV;
 228
 229         cpu_clkdm[0] = clkdm_lookup("mpu0_clkdm");
 230         cpu_clkdm[1] = clkdm_lookup("mpu1_clkdm");
 231         if (!cpu_clkdm[0] || !cpu_clkdm[1])
 232                 return -ENODEV;
 233
 234         return cpuidle_register(&omap4_idle_driver, cpu_online_mask);
 235 }