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 #include <linux/clockchips.h>
  18
  19 #include <asm/cpuidle.h>
  20 #include <asm/proc-fns.h>
  21
  22 #include "common.h"
  23 #include "pm.h"
  24 #include "prm.h"
  25 #include "clockdomain.h"
  26
  27 #define MAX_CPUS        2
  28
  29 /* Machine specific information */
  30 struct idle_statedata {
  31         u32 cpu_state;
  32         u32 mpu_logic_state;
  33         u32 mpu_state;
  34 };
  35
  36 static struct idle_statedata omap4_idle_data[] = {
  37         {
  38                 .cpu_state = PWRDM_POWER_ON,
  39                 .mpu_state = PWRDM_POWER_ON,
  40                 .mpu_logic_state = PWRDM_POWER_RET,
  41         },
  42         {
  43                 .cpu_state = PWRDM_POWER_OFF,
  44                 .mpu_state = PWRDM_POWER_RET,
  45                 .mpu_logic_state = PWRDM_POWER_RET,
  46         },
  47         {
  48                 .cpu_state = PWRDM_POWER_OFF,
  49                 .mpu_state = PWRDM_POWER_RET,
  50                 .mpu_logic_state = PWRDM_POWER_OFF,
  51         },
  52 };
  53
  54 static struct powerdomain *mpu_pd, *cpu_pd[MAX_CPUS];
  55 static struct clockdomain *cpu_clkdm[MAX_CPUS];
  56
  57 static atomic_t abort_barrier;
  58 static bool cpu_done[MAX_CPUS];
  59 static struct idle_statedata *state_ptr = &omap4_idle_data[0];
  60
  61 /* Private functions */
  62
  63 /**
  64  * omap_enter_idle_[simple/coupled] - OMAP4PLUS cpuidle entry functions
  65  * @dev: cpuidle device
  66  * @drv: cpuidle driver
  67  * @index: the index of state to be entered
  68  *
  69  * Called from the CPUidle framework to program the device to the
  70  * specified low power state selected by the governor.
  71  * Returns the amount of time spent in the low power state.
  72  */
  73 static int omap_enter_idle_simple(struct cpuidle_device *dev,
  74                         struct cpuidle_driver *drv,
  75                         int index)
  76 {
  77         omap_do_wfi();
  78         return index;
  79 }
  80
  81 static int omap_enter_idle_coupled(struct cpuidle_device *dev,
  82                         struct cpuidle_driver *drv,
  83                         int index)
  84 {
  85         struct idle_statedata *cx = state_ptr + index;
  86         u32 mpuss_can_lose_context = 0;
  87         int cpu_id = smp_processor_id();
  88
  89         /*
  90          * CPU0 has to wait and stay ON until CPU1 is OFF state.
  91          * This is necessary to honour hardware recommondation
  92          * of triggeing all the possible low power modes once CPU1 is
  93          * out of coherency and in OFF mode.
  94          */
  95         if (dev->cpu == 0 && cpumask_test_cpu(1, cpu_online_mask)) {
  96                 while (pwrdm_read_pwrst(cpu_pd[1]) != PWRDM_POWER_OFF) {
  97                         cpu_relax();
  98
  99                         /*
 100                          * CPU1 could have already entered & exited idle
 101                          * without hitting off because of a wakeup
 102                          * or a failed attempt to hit off mode.  Check for
 103                          * that here, otherwise we could spin forever
 104                          * waiting for CPU1 off.
 105                          */
 106                         if (cpu_done[1])
 107                             goto fail;
 108
 109                 }
 110         }
 111
 112         mpuss_can_lose_context = (cx->mpu_state == PWRDM_POWER_RET) &&
 113                                  (cx->mpu_logic_state == PWRDM_POWER_OFF);
 114
 115         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu_id);
 116
 117         /*
 118          * Call idle CPU PM enter notifier chain so that
 119          * VFP and per CPU interrupt context is saved.
 120          */
 121         cpu_pm_enter();
 122
 123         if (dev->cpu == 0) {
 124                 pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state);
 125                 omap_set_pwrdm_state(mpu_pd, cx->mpu_state);
 126
 127                 /*
 128                  * Call idle CPU cluster PM enter notifier chain
 129                  * to save GIC and wakeupgen context.
 130                  */
 131                 if (mpuss_can_lose_context)
 132                         cpu_cluster_pm_enter();
 133         }
 134
 135         omap4_enter_lowpower(dev->cpu, cx->cpu_state);
 136         cpu_done[dev->cpu] = true;
 137
 138         /* Wakeup CPU1 only if it is not offlined */
 139         if (dev->cpu == 0 && cpumask_test_cpu(1, cpu_online_mask)) {
 140
 141                 if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) &&
 142                     mpuss_can_lose_context)
 143                         gic_dist_disable();
 144
 145                 clkdm_wakeup(cpu_clkdm[1]);
 146                 omap_set_pwrdm_state(cpu_pd[1], PWRDM_POWER_ON);
 147                 clkdm_allow_idle(cpu_clkdm[1]);
 148
 149                 if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) &&
 150                     mpuss_can_lose_context) {
 151                         while (gic_dist_disabled()) {
 152                                 udelay(1);
 153                                 cpu_relax();
 154                         }
 155                         gic_timer_retrigger();
 156                 }
 157         }
 158
 159         /*
 160          * Call idle CPU PM exit notifier chain to restore
 161          * VFP and per CPU IRQ context.
 162          */
 163         cpu_pm_exit();
 164
 165         /*
 166          * Call idle CPU cluster PM exit notifier chain
 167          * to restore GIC and wakeupgen context.
 168          */
 169         if (dev->cpu == 0 && mpuss_can_lose_context)
 170                 cpu_cluster_pm_exit();
 171
 172         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu_id);
 173
 174 fail:
 175         cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
 176         cpu_done[dev->cpu] = false;
 177
 178         return index;
 179 }
 180
 181 /*
 182  * For each cpu, setup the broadcast timer because local timers
 183  * stops for the states above C1.
 184  */
 185 static void omap_setup_broadcast_timer(void *arg)
 186 {
 187         int cpu = smp_processor_id();
 188         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &cpu);
 189 }
 190
 191 static struct cpuidle_driver omap4_idle_driver = {
 192         .name                           = "omap4_idle",
 193         .owner                          = THIS_MODULE,
 194         .states = {
 195                 {
 196                         /* C1 - CPU0 ON + CPU1 ON + MPU ON */
 197                         .exit_latency = 2 + 2,
 198                         .target_residency = 5,
 199                         .enter = omap_enter_idle_simple,
 200                         .name = "C1",
 201                         .desc = "CPUx ON, MPUSS ON"
 202                 },
 203                 {
 204                         /* C2 - CPU0 OFF + CPU1 OFF + MPU CSWR */
 205                         .exit_latency = 328 + 440,
 206                         .target_residency = 960,
 207                         .flags = CPUIDLE_FLAG_COUPLED,
 208                         .enter = omap_enter_idle_coupled,
 209                         .name = "C2",
 210                         .desc = "CPUx OFF, MPUSS CSWR",
 211                 },
 212                 {
 213                         /* C3 - CPU0 OFF + CPU1 OFF + MPU OSWR */
 214                         .exit_latency = 460 + 518,
 215                         .target_residency = 1100,
 216                         .flags = CPUIDLE_FLAG_COUPLED,
 217                         .enter = omap_enter_idle_coupled,
 218                         .name = "C3",
 219                         .desc = "CPUx OFF, MPUSS OSWR",
 220                 },
 221         },
 222         .state_count = ARRAY_SIZE(omap4_idle_data),
 223         .safe_state_index = 0,
 224 };
 225
 226 /* Public functions */
 227
 228 /**
 229  * omap4_idle_init - Init routine for OMAP4+ idle
 230  *
 231  * Registers the OMAP4+ specific cpuidle driver to the cpuidle
 232  * framework with the valid set of states.
 233  */
 234 int __init omap4_idle_init(void)
 235 {
 236         mpu_pd = pwrdm_lookup("mpu_pwrdm");
 237         cpu_pd[0] = pwrdm_lookup("cpu0_pwrdm");
 238         cpu_pd[1] = pwrdm_lookup("cpu1_pwrdm");
 239         if ((!mpu_pd) || (!cpu_pd[0]) || (!cpu_pd[1]))
 240                 return -ENODEV;
 241
 242         cpu_clkdm[0] = clkdm_lookup("mpu0_clkdm");
 243         cpu_clkdm[1] = clkdm_lookup("mpu1_clkdm");
 244         if (!cpu_clkdm[0] || !cpu_clkdm[1])
 245                 return -ENODEV;
 246
 247         /* Configure the broadcast timer on each cpu */
 248         on_each_cpu(omap_setup_broadcast_timer, NULL, 1);
 249
 250         return cpuidle_register(&omap4_idle_driver, cpu_online_mask);
 251 }