arch/arm/mach-omap2/cpuidle34xx.c

   1 /*
   2  * linux/arch/arm/mach-omap2/cpuidle34xx.c
   3  *
   4  * OMAP3 CPU IDLE Routines
   5  *
   6  * Copyright (C) 2008 Texas Instruments, Inc.
   7  * Rajendra Nayak <rnayak@ti.com>
   8  *
   9  * Copyright (C) 2007 Texas Instruments, Inc.
  10  * Karthik Dasu <karthik-dp@ti.com>
  11  *
  12  * Copyright (C) 2006 Nokia Corporation
  13  * Tony Lindgren <tony@atomide.com>
  14  *
  15  * Copyright (C) 2005 Texas Instruments, Inc.
  16  * Richard Woodruff <r-woodruff2@ti.com>
  17  *
  18  * Based on pm.c for omap2
  19  *
  20  * This program is free software; you can redistribute it and/or modify
  21  * it under the terms of the GNU General Public License version 2 as
  22  * published by the Free Software Foundation.
  23  */
  24
  25 #include <linux/sched.h>
  26 #include <linux/cpuidle.h>
  27 #include <linux/export.h>
  28 #include <linux/cpu_pm.h>
  29 #include <asm/cpuidle.h>
  30
  31 #include "powerdomain.h"
  32 #include "clockdomain.h"
  33
  34 #include "pm.h"
  35 #include "control.h"
  36 #include "common.h"
  37
  38 /* Mach specific information to be recorded in the C-state driver_data */
  39 struct omap3_idle_statedata {
  40         u8 mpu_state;
  41         u8 core_state;
  42         u8 per_min_state;
  43         u8 flags;
  44 };
  45
  46 static struct powerdomain *mpu_pd, *core_pd, *per_pd, *cam_pd;
  47
  48 /*
  49  * Possible flag bits for struct omap3_idle_statedata.flags:
  50  *
  51  * OMAP_CPUIDLE_CX_NO_CLKDM_IDLE: don't allow the MPU clockdomain to go
  52  *    inactive.  This in turn prevents the MPU DPLL from entering autoidle
  53  *    mode, so wakeup latency is greatly reduced, at the cost of additional
  54  *    energy consumption.  This also prevents the CORE clockdomain from
  55  *    entering idle.
  56  */
  57 #define OMAP_CPUIDLE_CX_NO_CLKDM_IDLE           BIT(0)
  58
  59 /*
  60  * Prevent PER OFF if CORE is not in RETention or OFF as this would
  61  * disable PER wakeups completely.
  62  */
  63 static struct omap3_idle_statedata omap3_idle_data[] = {
  64         {
  65                 .mpu_state = PWRDM_POWER_ON,
  66                 .core_state = PWRDM_POWER_ON,
  67                 /* In C1 do not allow PER state lower than CORE state */
  68                 .per_min_state = PWRDM_POWER_ON,
  69                 .flags = OMAP_CPUIDLE_CX_NO_CLKDM_IDLE,
  70         },
  71         {
  72                 .mpu_state = PWRDM_POWER_ON,
  73                 .core_state = PWRDM_POWER_ON,
  74                 .per_min_state = PWRDM_POWER_RET,
  75         },
  76         {
  77                 .mpu_state = PWRDM_POWER_RET,
  78                 .core_state = PWRDM_POWER_ON,
  79                 .per_min_state = PWRDM_POWER_RET,
  80         },
  81         {
  82                 .mpu_state = PWRDM_POWER_OFF,
  83                 .core_state = PWRDM_POWER_ON,
  84                 .per_min_state = PWRDM_POWER_RET,
  85         },
  86         {
  87                 .mpu_state = PWRDM_POWER_RET,
  88                 .core_state = PWRDM_POWER_RET,
  89                 .per_min_state = PWRDM_POWER_OFF,
  90         },
  91         {
  92                 .mpu_state = PWRDM_POWER_OFF,
  93                 .core_state = PWRDM_POWER_RET,
  94                 .per_min_state = PWRDM_POWER_OFF,
  95         },
  96         {
  97                 .mpu_state = PWRDM_POWER_OFF,
  98                 .core_state = PWRDM_POWER_OFF,
  99                 .per_min_state = PWRDM_POWER_OFF,
 100         },
 101 };
 102
 103 /**
 104  * omap3_enter_idle - Programs OMAP3 to enter the specified state
 105  * @dev: cpuidle device
 106  * @drv: cpuidle driver
 107  * @index: the index of state to be entered
 108  */
 109 static int omap3_enter_idle(struct cpuidle_device *dev,
 110                             struct cpuidle_driver *drv,
 111                             int index)
 112 {
 113         struct omap3_idle_statedata *cx = &omap3_idle_data[index];
 114
 115         if (omap_irq_pending() || need_resched())
 116                 goto return_sleep_time;
 117
 118         /* Deny idle for C1 */
 119         if (cx->flags & OMAP_CPUIDLE_CX_NO_CLKDM_IDLE) {
 120                 clkdm_deny_idle(mpu_pd->pwrdm_clkdms[0]);
 121         } else {
 122                 pwrdm_set_next_pwrst(mpu_pd, cx->mpu_state);
 123                 pwrdm_set_next_pwrst(core_pd, cx->core_state);
 124         }
 125
 126         /*
 127          * Call idle CPU PM enter notifier chain so that
 128          * VFP context is saved.
 129          */
 130         if (cx->mpu_state == PWRDM_POWER_OFF)
 131                 cpu_pm_enter();
 132
 133         /* Execute ARM wfi */
 134         omap_sram_idle();
 135
 136         /*
 137          * Call idle CPU PM enter notifier chain to restore
 138          * VFP context.
 139          */
 140         if (cx->mpu_state == PWRDM_POWER_OFF &&
 141             pwrdm_read_prev_pwrst(mpu_pd) == PWRDM_POWER_OFF)
 142                 cpu_pm_exit();
 143
 144         /* Re-allow idle for C1 */
 145         if (cx->flags & OMAP_CPUIDLE_CX_NO_CLKDM_IDLE)
 146                 clkdm_allow_idle(mpu_pd->pwrdm_clkdms[0]);
 147
 148 return_sleep_time:
 149
 150         return index;
 151 }
 152
 153 /**
 154  * next_valid_state - Find next valid C-state
 155  * @dev: cpuidle device
 156  * @drv: cpuidle driver
 157  * @index: Index of currently selected c-state
 158  *
 159  * If the state corresponding to index is valid, index is returned back
 160  * to the caller. Else, this function searches for a lower c-state which is
 161  * still valid (as defined in omap3_power_states[]) and returns its index.
 162  *
 163  * A state is valid if the 'valid' field is enabled and
 164  * if it satisfies the enable_off_mode condition.
 165  */
 166 static int next_valid_state(struct cpuidle_device *dev,
 167                             struct cpuidle_driver *drv, int index)
 168 {
 169         struct omap3_idle_statedata *cx = &omap3_idle_data[index];
 170         u32 mpu_deepest_state = PWRDM_POWER_RET;
 171         u32 core_deepest_state = PWRDM_POWER_RET;
 172         int idx;
 173         int next_index = 0; /* C1 is the default value */
 174
 175         if (enable_off_mode) {
 176                 mpu_deepest_state = PWRDM_POWER_OFF;
 177                 /*
 178                  * Erratum i583: valable for ES rev < Es1.2 on 3630.
 179                  * CORE OFF mode is not supported in a stable form, restrict
 180                  * instead the CORE state to RET.
 181                  */
 182                 if (!IS_PM34XX_ERRATUM(PM_SDRC_WAKEUP_ERRATUM_i583))
 183                         core_deepest_state = PWRDM_POWER_OFF;
 184         }
 185
 186         /* Check if current state is valid */
 187         if ((cx->mpu_state >= mpu_deepest_state) &&
 188             (cx->core_state >= core_deepest_state))
 189                 return index;
 190
 191         /*
 192          * Drop to next valid state.
 193          * Start search from the next (lower) state.
 194          */
 195         for (idx = index - 1; idx >= 0; idx--) {
 196                 cx = &omap3_idle_data[idx];
 197                 if ((cx->mpu_state >= mpu_deepest_state) &&
 198                     (cx->core_state >= core_deepest_state)) {
 199                         next_index = idx;
 200                         break;
 201                 }
 202         }
 203
 204         return next_index;
 205 }
 206
 207 /**
 208  * omap3_enter_idle_bm - Checks for any bus activity
 209  * @dev: cpuidle device
 210  * @drv: cpuidle driver
 211  * @index: array index of target state to be programmed
 212  *
 213  * This function checks for any pending activity and then programs
 214  * the device to the specified or a safer state.
 215  */
 216 static int omap3_enter_idle_bm(struct cpuidle_device *dev,
 217                                struct cpuidle_driver *drv,
 218                                int index)
 219 {
 220         int new_state_idx, ret;
 221         u8 per_next_state, per_saved_state;
 222         struct omap3_idle_statedata *cx;
 223
 224         /*
 225          * Use only C1 if CAM is active.
 226          * CAM does not have wakeup capability in OMAP3.
 227          */
 228         if (pwrdm_read_pwrst(cam_pd) == PWRDM_POWER_ON)
 229                 new_state_idx = drv->safe_state_index;
 230         else
 231                 new_state_idx = next_valid_state(dev, drv, index);
 232
 233         /*
 234          * FIXME: we currently manage device-specific idle states
 235          *        for PER and CORE in combination with CPU-specific
 236          *        idle states.  This is wrong, and device-specific
 237          *        idle management needs to be separated out into
 238          *        its own code.
 239          */
 240
 241         /* Program PER state */
 242         cx = &omap3_idle_data[new_state_idx];
 243
 244         per_next_state = pwrdm_read_next_pwrst(per_pd);
 245         per_saved_state = per_next_state;
 246         if (per_next_state < cx->per_min_state) {
 247                 per_next_state = cx->per_min_state;
 248                 pwrdm_set_next_pwrst(per_pd, per_next_state);
 249         }
 250
 251         ret = omap3_enter_idle(dev, drv, new_state_idx);
 252
 253         /* Restore original PER state if it was modified */
 254         if (per_next_state != per_saved_state)
 255                 pwrdm_set_next_pwrst(per_pd, per_saved_state);
 256
 257         return ret;
 258 }
 259
 260 static struct cpuidle_driver omap3_idle_driver = {
 261         .name             = "omap3_idle",
 262         .owner            = THIS_MODULE,
 263         .states = {
 264                 {
 265                         .enter            = omap3_enter_idle_bm,
 266                         .exit_latency     = 2 + 2,
 267                         .target_residency = 5,
 268                         .name             = "C1",
 269                         .desc             = "MPU ON + CORE ON",
 270                 },
 271                 {
 272                         .enter            = omap3_enter_idle_bm,
 273                         .exit_latency     = 10 + 10,
 274                         .target_residency = 30,
 275                         .name             = "C2",
 276                         .desc             = "MPU ON + CORE ON",
 277                 },
 278                 {
 279                         .enter            = omap3_enter_idle_bm,
 280                         .exit_latency     = 50 + 50,
 281                         .target_residency = 300,
 282                         .name             = "C3",
 283                         .desc             = "MPU RET + CORE ON",
 284                 },
 285                 {
 286                         .enter            = omap3_enter_idle_bm,
 287                         .exit_latency     = 1500 + 1800,
 288                         .target_residency = 4000,
 289                         .name             = "C4",
 290                         .desc             = "MPU OFF + CORE ON",
 291                 },
 292                 {
 293                         .enter            = omap3_enter_idle_bm,
 294                         .exit_latency     = 2500 + 7500,
 295                         .target_residency = 12000,
 296                         .name             = "C5",
 297                         .desc             = "MPU RET + CORE RET",
 298                 },
 299                 {
 300                         .enter            = omap3_enter_idle_bm,
 301                         .exit_latency     = 3000 + 8500,
 302                         .target_residency = 15000,
 303                         .name             = "C6",
 304                         .desc             = "MPU OFF + CORE RET",
 305                 },
 306                 {
 307                         .enter            = omap3_enter_idle_bm,
 308                         .exit_latency     = 10000 + 30000,
 309                         .target_residency = 30000,
 310                         .name             = "C7",
 311                         .desc             = "MPU OFF + CORE OFF",
 312                 },
 313         },
 314         .state_count = ARRAY_SIZE(omap3_idle_data),
 315         .safe_state_index = 0,
 316 };
 317
 318 /* Public functions */
 319
 320 /**
 321  * omap3_idle_init - Init routine for OMAP3 idle
 322  *
 323  * Registers the OMAP3 specific cpuidle driver to the cpuidle
 324  * framework with the valid set of states.
 325  */
 326 int __init omap3_idle_init(void)
 327 {
 328         mpu_pd = pwrdm_lookup("mpu_pwrdm");
 329         core_pd = pwrdm_lookup("core_pwrdm");
 330         per_pd = pwrdm_lookup("per_pwrdm");
 331         cam_pd = pwrdm_lookup("cam_pwrdm");
 332
 333         if (!mpu_pd || !core_pd || !per_pd || !cam_pd)
 334                 return -ENODEV;
 335
 336         return cpuidle_register(&omap3_idle_driver, NULL);
 337 }