drivers/acpi/processor_thermal.c

   1 /*
   2  * processor_thermal.c - Passive cooling submodule of the ACPI processor driver
   3  *
   4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   6  *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
   7  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   8  *                      - Added processor hotplug support
   9  *
  10  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License as published by
  14  *  the Free Software Foundation; either version 2 of the License, or (at
  15  *  your option) any later version.
  16  *
  17  *  This program is distributed in the hope that it will be useful, but
  18  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  *  General Public License for more details.
  21  *
  22  *  You should have received a copy of the GNU General Public License along
  23  *  with this program; if not, write to the Free Software Foundation, Inc.,
  24  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  25  *
  26  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  27  */
  28
  29 #include <linux/kernel.h>
  30 #include <linux/module.h>
  31 #include <linux/init.h>
  32 #include <linux/cpufreq.h>
  33 #include <linux/sysdev.h>
  34
  35 #include <asm/uaccess.h>
  36
  37 #include <acpi/acpi_bus.h>
  38 #include <acpi/processor.h>
  39 #include <acpi/acpi_drivers.h>
  40
  41 #define PREFIX "ACPI: "
  42
  43 #define ACPI_PROCESSOR_CLASS            "processor"
  44 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  45 ACPI_MODULE_NAME("processor_thermal");
  46
  47 /* --------------------------------------------------------------------------
  48                                  Limit Interface
  49    -------------------------------------------------------------------------- */
  50 static int acpi_processor_apply_limit(struct acpi_processor *pr)
  51 {
  52         int result = 0;
  53         u16 px = 0;
  54         u16 tx = 0;
  55
  56
  57         if (!pr)
  58                 return -EINVAL;
  59
  60         if (!pr->flags.limit)
  61                 return -ENODEV;
  62
  63         if (pr->flags.throttling) {
  64                 if (pr->limit.user.tx > tx)
  65                         tx = pr->limit.user.tx;
  66                 if (pr->limit.thermal.tx > tx)
  67                         tx = pr->limit.thermal.tx;
  68
  69                 result = acpi_processor_set_throttling(pr, tx, false);
  70                 if (result)
  71                         goto end;
  72         }
  73
  74         pr->limit.state.px = px;
  75         pr->limit.state.tx = tx;
  76
  77         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  78                           "Processor [%d] limit set to (P%d:T%d)\n", pr->id,
  79                           pr->limit.state.px, pr->limit.state.tx));
  80
  81       end:
  82         if (result)
  83                 printk(KERN_ERR PREFIX "Unable to set limit\n");
  84
  85         return result;
  86 }
  87
  88 #ifdef CONFIG_CPU_FREQ
  89
  90 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it
  91  * offers (in most cases) voltage scaling in addition to frequency scaling, and
  92  * thus a cubic (instead of linear) reduction of energy. Also, we allow for
  93  * _any_ cpufreq driver and not only the acpi-cpufreq driver.
  94  */
  95
  96 #define CPUFREQ_THERMAL_MIN_STEP 0
  97 #define CPUFREQ_THERMAL_MAX_STEP 3
  98
  99 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
 100 static unsigned int acpi_thermal_cpufreq_is_init = 0;
 101
 102 static int cpu_has_cpufreq(unsigned int cpu)
 103 {
 104         struct cpufreq_policy policy;
 105         if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu))
 106                 return 0;
 107         return 1;
 108 }
 109
 110 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
 111 {
 112         if (!cpu_has_cpufreq(cpu))
 113                 return -ENODEV;
 114
 115         if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) <
 116                 CPUFREQ_THERMAL_MAX_STEP) {
 117                 per_cpu(cpufreq_thermal_reduction_pctg, cpu)++;
 118                 cpufreq_update_policy(cpu);
 119                 return 0;
 120         }
 121
 122         return -ERANGE;
 123 }
 124
 125 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
 126 {
 127         if (!cpu_has_cpufreq(cpu))
 128                 return -ENODEV;
 129
 130         if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) >
 131                 (CPUFREQ_THERMAL_MIN_STEP + 1))
 132                 per_cpu(cpufreq_thermal_reduction_pctg, cpu)--;
 133         else
 134                 per_cpu(cpufreq_thermal_reduction_pctg, cpu) = 0;
 135         cpufreq_update_policy(cpu);
 136         /* We reached max freq again and can leave passive mode */
 137         return !per_cpu(cpufreq_thermal_reduction_pctg, cpu);
 138 }
 139
 140 static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
 141                                          unsigned long event, void *data)
 142 {
 143         struct cpufreq_policy *policy = data;
 144         unsigned long max_freq = 0;
 145
 146         if (event != CPUFREQ_ADJUST)
 147                 goto out;
 148
 149         max_freq = (
 150             policy->cpuinfo.max_freq *
 151             (100 - per_cpu(cpufreq_thermal_reduction_pctg, policy->cpu) * 20)
 152         ) / 100;
 153
 154         cpufreq_verify_within_limits(policy, 0, max_freq);
 155
 156       out:
 157         return 0;
 158 }
 159
 160 static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
 161         .notifier_call = acpi_thermal_cpufreq_notifier,
 162 };
 163
 164 static int cpufreq_get_max_state(unsigned int cpu)
 165 {
 166         if (!cpu_has_cpufreq(cpu))
 167                 return 0;
 168
 169         return CPUFREQ_THERMAL_MAX_STEP;
 170 }
 171
 172 static int cpufreq_get_cur_state(unsigned int cpu)
 173 {
 174         if (!cpu_has_cpufreq(cpu))
 175                 return 0;
 176
 177         return per_cpu(cpufreq_thermal_reduction_pctg, cpu);
 178 }
 179
 180 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 181 {
 182         if (!cpu_has_cpufreq(cpu))
 183                 return 0;
 184
 185         per_cpu(cpufreq_thermal_reduction_pctg, cpu) = state;
 186         cpufreq_update_policy(cpu);
 187         return 0;
 188 }
 189
 190 void acpi_thermal_cpufreq_init(void)
 191 {
 192         int i;
 193
 194         for (i = 0; i < nr_cpu_ids; i++)
 195                 if (cpu_present(i))
 196                         per_cpu(cpufreq_thermal_reduction_pctg, i) = 0;
 197
 198         i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
 199                                       CPUFREQ_POLICY_NOTIFIER);
 200         if (!i)
 201                 acpi_thermal_cpufreq_is_init = 1;
 202 }
 203
 204 void acpi_thermal_cpufreq_exit(void)
 205 {
 206         if (acpi_thermal_cpufreq_is_init)
 207                 cpufreq_unregister_notifier
 208                     (&acpi_thermal_cpufreq_notifier_block,
 209                      CPUFREQ_POLICY_NOTIFIER);
 210
 211         acpi_thermal_cpufreq_is_init = 0;
 212 }
 213
 214 #else                           /* ! CONFIG_CPU_FREQ */
 215 static int cpufreq_get_max_state(unsigned int cpu)
 216 {
 217         return 0;
 218 }
 219
 220 static int cpufreq_get_cur_state(unsigned int cpu)
 221 {
 222         return 0;
 223 }
 224
 225 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 226 {
 227         return 0;
 228 }
 229
 230 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
 231 {
 232         return -ENODEV;
 233 }
 234 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
 235 {
 236         return -ENODEV;
 237 }
 238
 239 #endif
 240
 241 int acpi_processor_set_thermal_limit(acpi_handle handle, int type)
 242 {
 243         int result = 0;
 244         struct acpi_processor *pr = NULL;
 245         struct acpi_device *device = NULL;
 246         int tx = 0, max_tx_px = 0;
 247
 248
 249         if ((type < ACPI_PROCESSOR_LIMIT_NONE)
 250             || (type > ACPI_PROCESSOR_LIMIT_DECREMENT))
 251                 return -EINVAL;
 252
 253         result = acpi_bus_get_device(handle, &device);
 254         if (result)
 255                 return result;
 256
 257         pr = acpi_driver_data(device);
 258         if (!pr)
 259                 return -ENODEV;
 260
 261         /* Thermal limits are always relative to the current Px/Tx state. */
 262         if (pr->flags.throttling)
 263                 pr->limit.thermal.tx = pr->throttling.state;
 264
 265         /*
 266          * Our default policy is to only use throttling at the lowest
 267          * performance state.
 268          */
 269
 270         tx = pr->limit.thermal.tx;
 271
 272         switch (type) {
 273
 274         case ACPI_PROCESSOR_LIMIT_NONE:
 275                 do {
 276                         result = acpi_thermal_cpufreq_decrease(pr->id);
 277                 } while (!result);
 278                 tx = 0;
 279                 break;
 280
 281         case ACPI_PROCESSOR_LIMIT_INCREMENT:
 282                 /* if going up: P-states first, T-states later */
 283
 284                 result = acpi_thermal_cpufreq_increase(pr->id);
 285                 if (!result)
 286                         goto end;
 287                 else if (result == -ERANGE)
 288                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 289                                           "At maximum performance state\n"));
 290
 291                 if (pr->flags.throttling) {
 292                         if (tx == (pr->throttling.state_count - 1))
 293                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 294                                                   "At maximum throttling state\n"));
 295                         else
 296                                 tx++;
 297                 }
 298                 break;
 299
 300         case ACPI_PROCESSOR_LIMIT_DECREMENT:
 301                 /* if going down: T-states first, P-states later */
 302
 303                 if (pr->flags.throttling) {
 304                         if (tx == 0) {
 305                                 max_tx_px = 1;
 306                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 307                                                   "At minimum throttling state\n"));
 308                         } else {
 309                                 tx--;
 310                                 goto end;
 311                         }
 312                 }
 313
 314                 result = acpi_thermal_cpufreq_decrease(pr->id);
 315                 if (result) {
 316                         /*
 317                          * We only could get -ERANGE, 1 or 0.
 318                          * In the first two cases we reached max freq again.
 319                          */
 320                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 321                                           "At minimum performance state\n"));
 322                         max_tx_px = 1;
 323                 } else
 324                         max_tx_px = 0;
 325
 326                 break;
 327         }
 328
 329       end:
 330         if (pr->flags.throttling) {
 331                 pr->limit.thermal.px = 0;
 332                 pr->limit.thermal.tx = tx;
 333
 334                 result = acpi_processor_apply_limit(pr);
 335                 if (result)
 336                         printk(KERN_ERR PREFIX "Unable to set thermal limit\n");
 337
 338                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Thermal limit now (P%d:T%d)\n",
 339                                   pr->limit.thermal.px, pr->limit.thermal.tx));
 340         } else
 341                 result = 0;
 342         if (max_tx_px)
 343                 return 1;
 344         else
 345                 return result;
 346 }
 347
 348 int acpi_processor_get_limit_info(struct acpi_processor *pr)
 349 {
 350
 351         if (!pr)
 352                 return -EINVAL;
 353
 354         if (pr->flags.throttling)
 355                 pr->flags.limit = 1;
 356
 357         return 0;
 358 }
 359
 360 /* thermal coolign device callbacks */
 361 static int acpi_processor_max_state(struct acpi_processor *pr)
 362 {
 363         int max_state = 0;
 364
 365         /*
 366          * There exists four states according to
 367          * cpufreq_thermal_reduction_ptg. 0, 1, 2, 3
 368          */
 369         max_state += cpufreq_get_max_state(pr->id);
 370         if (pr->flags.throttling)
 371                 max_state += (pr->throttling.state_count -1);
 372
 373         return max_state;
 374 }
 375 static int
 376 processor_get_max_state(struct thermal_cooling_device *cdev,
 377                         unsigned long *state)
 378 {
 379         struct acpi_device *device = cdev->devdata;
 380         struct acpi_processor *pr = acpi_driver_data(device);
 381
 382         if (!device || !pr)
 383                 return -EINVAL;
 384
 385         *state = acpi_processor_max_state(pr);
 386         return 0;
 387 }
 388
 389 static int
 390 processor_get_cur_state(struct thermal_cooling_device *cdev,
 391                         unsigned long *cur_state)
 392 {
 393         struct acpi_device *device = cdev->devdata;
 394         struct acpi_processor *pr = acpi_driver_data(device);
 395
 396         if (!device || !pr)
 397                 return -EINVAL;
 398
 399         *cur_state = cpufreq_get_cur_state(pr->id);
 400         if (pr->flags.throttling)
 401                 *cur_state += pr->throttling.state;
 402         return 0;
 403 }
 404
 405 static int
 406 processor_set_cur_state(struct thermal_cooling_device *cdev,
 407                         unsigned long state)
 408 {
 409         struct acpi_device *device = cdev->devdata;
 410         struct acpi_processor *pr = acpi_driver_data(device);
 411         int result = 0;
 412         int max_pstate;
 413
 414         if (!device || !pr)
 415                 return -EINVAL;
 416
 417         max_pstate = cpufreq_get_max_state(pr->id);
 418
 419         if (state > acpi_processor_max_state(pr))
 420                 return -EINVAL;
 421
 422         if (state <= max_pstate) {
 423                 if (pr->flags.throttling && pr->throttling.state)
 424                         result = acpi_processor_set_throttling(pr, 0, false);
 425                 cpufreq_set_cur_state(pr->id, state);
 426         } else {
 427                 cpufreq_set_cur_state(pr->id, max_pstate);
 428                 result = acpi_processor_set_throttling(pr,
 429                                 state - max_pstate, false);
 430         }
 431         return result;
 432 }
 433
 434 struct thermal_cooling_device_ops processor_cooling_ops = {
 435         .get_max_state = processor_get_max_state,
 436         .get_cur_state = processor_get_cur_state,
 437         .set_cur_state = processor_set_cur_state,
 438 };