kernel/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/tick.h>
  18
  19 #include <asm/cpuidle.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         tick_broadcast_enter();
 114
 115         /*
 116          * Call idle CPU PM enter notifier chain so that
 117          * VFP and per CPU interrupt context is saved.
 118          */
 119         cpu_pm_enter();
 120
 121         if (dev->cpu == 0) {
 122                 pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state);
 123                 omap_set_pwrdm_state(mpu_pd, cx->mpu_state);
 124
 125                 /*
 126                  * Call idle CPU cluster PM enter notifier chain
 127                  * to save GIC and wakeupgen context.
 128                  */
 129                 if (mpuss_can_lose_context)
 130                         cpu_cluster_pm_enter();
 131         }
 132
 133         omap4_enter_lowpower(dev->cpu, cx->cpu_state);
 134         cpu_done[dev->cpu] = true;
 135
 136         /* Wakeup CPU1 only if it is not offlined */
 137         if (dev->cpu == 0 && cpumask_test_cpu(1, cpu_online_mask)) {
 138
 139                 if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) &&
 140                     mpuss_can_lose_context)
 141                         gic_dist_disable();
 142
 143                 clkdm_wakeup(cpu_clkdm[1]);
 144                 omap_set_pwrdm_state(cpu_pd[1], PWRDM_POWER_ON);
 145                 clkdm_allow_idle(cpu_clkdm[1]);
 146
 147                 if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) &&
 148                     mpuss_can_lose_context) {
 149                         while (gic_dist_disabled()) {
 150                                 udelay(1);
 151                                 cpu_relax();
 152                         }
 153                         gic_timer_retrigger();
 154                 }
 155         }
 156
 157         /*
 158          * Call idle CPU PM exit notifier chain to restore
 159          * VFP and per CPU IRQ context.
 160          */
 161         cpu_pm_exit();
 162
 163         /*
 164          * Call idle CPU cluster PM exit notifier chain
 165          * to restore GIC and wakeupgen context.
 166          */
 167         if (dev->cpu == 0 && mpuss_can_lose_context)
 168                 cpu_cluster_pm_exit();
 169
 170         tick_broadcast_exit();
 171
 172 fail:
 173         cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
 174         cpu_done[dev->cpu] = false;
 175
 176         return index;
 177 }
 178
 179 /*
 180  * For each cpu, setup the broadcast timer because local timers
 181  * stops for the states above C1.
 182  */
 183 static void omap_setup_broadcast_timer(void *arg)
 184 {
 185         tick_broadcast_enable();
 186 }
 187
 188 static struct cpuidle_driver omap4_idle_driver = {
 189         .name                           = "omap4_idle",
 190         .owner                          = THIS_MODULE,
 191         .states = {
 192                 {
 193                         /* C1 - CPU0 ON + CPU1 ON + MPU ON */
 194                         .exit_latency = 2 + 2,
 195                         .target_residency = 5,
 196                         .enter = omap_enter_idle_simple,
 197                         .name = "C1",
 198                         .desc = "CPUx ON, MPUSS ON"
 199                 },
 200                 {
 201                         /* C2 - CPU0 OFF + CPU1 OFF + MPU CSWR */
 202                         .exit_latency = 328 + 440,
 203                         .target_residency = 960,
 204                         .flags = CPUIDLE_FLAG_COUPLED,
 205                         .enter = omap_enter_idle_coupled,
 206                         .name = "C2",
 207                         .desc = "CPUx OFF, MPUSS CSWR",
 208                 },
 209                 {
 210                         /* C3 - CPU0 OFF + CPU1 OFF + MPU OSWR */
 211                         .exit_latency = 460 + 518,
 212                         .target_residency = 1100,
 213                         .flags = CPUIDLE_FLAG_COUPLED,
 214                         .enter = omap_enter_idle_coupled,
 215                         .name = "C3",
 216                         .desc = "CPUx OFF, MPUSS OSWR",
 217                 },
 218         },
 219         .state_count = ARRAY_SIZE(omap4_idle_data),
 220         .safe_state_index = 0,
 221 };
 222
 223 /* Public functions */
 224
 225 /**
 226  * omap4_idle_init - Init routine for OMAP4+ idle
 227  *
 228  * Registers the OMAP4+ specific cpuidle driver to the cpuidle
 229  * framework with the valid set of states.
 230  */
 231 int __init omap4_idle_init(void)
 232 {
 233         mpu_pd = pwrdm_lookup("mpu_pwrdm");
 234         cpu_pd[0] = pwrdm_lookup("cpu0_pwrdm");
 235         cpu_pd[1] = pwrdm_lookup("cpu1_pwrdm");
 236         if ((!mpu_pd) || (!cpu_pd[0]) || (!cpu_pd[1]))
 237                 return -ENODEV;
 238
 239         cpu_clkdm[0] = clkdm_lookup("mpu0_clkdm");
 240         cpu_clkdm[1] = clkdm_lookup("mpu1_clkdm");
 241         if (!cpu_clkdm[0] || !cpu_clkdm[1])
 242                 return -ENODEV;
 243
 244         /* Configure the broadcast timer on each cpu */
 245         on_each_cpu(omap_setup_broadcast_timer, NULL, 1);
 246
 247         return cpuidle_register(&omap4_idle_driver, cpu_online_mask);
 248 }