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