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/proc_fs.h>
  34 #include <linux/seq_file.h>
  35 #include <linux/sysdev.h>
  36
  37 #include <asm/uaccess.h>
  38
  39 #include <acpi/acpi_bus.h>
  40 #include <acpi/processor.h>
  41 #include <acpi/acpi_drivers.h>
  42
  43 #define ACPI_PROCESSOR_COMPONENT        0x01000000
  44 #define ACPI_PROCESSOR_CLASS            "processor"
  45 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  46 ACPI_MODULE_NAME("processor_thermal");
  47
  48 /* --------------------------------------------------------------------------
  49                                  Limit Interface
  50    -------------------------------------------------------------------------- */
  51 static int acpi_processor_apply_limit(struct acpi_processor *pr)
  52 {
  53         int result = 0;
  54         u16 px = 0;
  55         u16 tx = 0;
  56
  57
  58         if (!pr)
  59                 return -EINVAL;
  60
  61         if (!pr->flags.limit)
  62                 return -ENODEV;
  63
  64         if (pr->flags.throttling) {
  65                 if (pr->limit.user.tx > tx)
  66                         tx = pr->limit.user.tx;
  67                 if (pr->limit.thermal.tx > tx)
  68                         tx = pr->limit.thermal.tx;
  69
  70                 result = acpi_processor_set_throttling(pr, tx);
  71                 if (result)
  72                         goto end;
  73         }
  74
  75         pr->limit.state.px = px;
  76         pr->limit.state.tx = tx;
  77
  78         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  79                           "Processor [%d] limit set to (P%d:T%d)\n", pr->id,
  80                           pr->limit.state.px, pr->limit.state.tx));
  81
  82       end:
  83         if (result)
  84                 printk(KERN_ERR PREFIX "Unable to set limit\n");
  85
  86         return result;
  87 }
  88
  89 #ifdef CONFIG_CPU_FREQ
  90
  91 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it
  92  * offers (in most cases) voltage scaling in addition to frequency scaling, and
  93  * thus a cubic (instead of linear) reduction of energy. Also, we allow for
  94  * _any_ cpufreq driver and not only the acpi-cpufreq driver.
  95  */
  96
  97 #define CPUFREQ_THERMAL_MIN_STEP 0
  98 #define CPUFREQ_THERMAL_MAX_STEP 3
  99
 100 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
 101 static unsigned int acpi_thermal_cpufreq_is_init = 0;
 102
 103 static int cpu_has_cpufreq(unsigned int cpu)
 104 {
 105         struct cpufreq_policy policy;
 106         if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu))
 107                 return 0;
 108         return 1;
 109 }
 110
 111 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
 112 {
 113         if (!cpu_has_cpufreq(cpu))
 114                 return -ENODEV;
 115
 116         if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) <
 117                 CPUFREQ_THERMAL_MAX_STEP) {
 118                 per_cpu(cpufreq_thermal_reduction_pctg, cpu)++;
 119                 cpufreq_update_policy(cpu);
 120                 return 0;
 121         }
 122
 123         return -ERANGE;
 124 }
 125
 126 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
 127 {
 128         if (!cpu_has_cpufreq(cpu))
 129                 return -ENODEV;
 130
 131         if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) >
 132                 (CPUFREQ_THERMAL_MIN_STEP + 1))
 133                 per_cpu(cpufreq_thermal_reduction_pctg, cpu)--;
 134         else
 135                 per_cpu(cpufreq_thermal_reduction_pctg, cpu) = 0;
 136         cpufreq_update_policy(cpu);
 137         /* We reached max freq again and can leave passive mode */
 138         return !per_cpu(cpufreq_thermal_reduction_pctg, cpu);
 139 }
 140
 141 static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
 142                                          unsigned long event, void *data)
 143 {
 144         struct cpufreq_policy *policy = data;
 145         unsigned long max_freq = 0;
 146
 147         if (event != CPUFREQ_ADJUST)
 148                 goto out;
 149
 150         max_freq = (
 151             policy->cpuinfo.max_freq *
 152             (100 - per_cpu(cpufreq_thermal_reduction_pctg, policy->cpu) * 20)
 153         ) / 100;
 154
 155         cpufreq_verify_within_limits(policy, 0, max_freq);
 156
 157       out:
 158         return 0;
 159 }
 160
 161 static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
 162         .notifier_call = acpi_thermal_cpufreq_notifier,
 163 };
 164
 165 static int cpufreq_get_max_state(unsigned int cpu)
 166 {
 167         if (!cpu_has_cpufreq(cpu))
 168                 return 0;
 169
 170         return CPUFREQ_THERMAL_MAX_STEP;
 171 }
 172
 173 static int cpufreq_get_cur_state(unsigned int cpu)
 174 {
 175         if (!cpu_has_cpufreq(cpu))
 176                 return 0;
 177
 178         return per_cpu(cpufreq_thermal_reduction_pctg, cpu);
 179 }
 180
 181 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 182 {
 183         if (!cpu_has_cpufreq(cpu))
 184                 return 0;
 185
 186         per_cpu(cpufreq_thermal_reduction_pctg, cpu) = state;
 187         cpufreq_update_policy(cpu);
 188         return 0;
 189 }
 190
 191 void acpi_thermal_cpufreq_init(void)
 192 {
 193         int i;
 194
 195         for (i = 0; i < nr_cpu_ids; i++)
 196                 if (cpu_present(i))
 197                         per_cpu(cpufreq_thermal_reduction_pctg, i) = 0;
 198
 199         i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
 200                                       CPUFREQ_POLICY_NOTIFIER);
 201         if (!i)
 202                 acpi_thermal_cpufreq_is_init = 1;
 203 }
 204
 205 void acpi_thermal_cpufreq_exit(void)
 206 {
 207         if (acpi_thermal_cpufreq_is_init)
 208                 cpufreq_unregister_notifier
 209                     (&acpi_thermal_cpufreq_notifier_block,
 210                      CPUFREQ_POLICY_NOTIFIER);
 211
 212         acpi_thermal_cpufreq_is_init = 0;
 213 }
 214
 215 #else                           /* ! CONFIG_CPU_FREQ */
 216 static int cpufreq_get_max_state(unsigned int cpu)
 217 {
 218         return 0;
 219 }
 220
 221 static int cpufreq_get_cur_state(unsigned int cpu)
 222 {
 223         return 0;
 224 }
 225
 226 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 227 {
 228         return 0;
 229 }
 230
 231 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
 232 {
 233         return -ENODEV;
 234 }
 235 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
 236 {
 237         return -ENODEV;
 238 }
 239
 240 #endif
 241
 242 int acpi_processor_set_thermal_limit(acpi_handle handle, int type)
 243 {
 244         int result = 0;
 245         struct acpi_processor *pr = NULL;
 246         struct acpi_device *device = NULL;
 247         int tx = 0, max_tx_px = 0;
 248
 249
 250         if ((type < ACPI_PROCESSOR_LIMIT_NONE)
 251             || (type > ACPI_PROCESSOR_LIMIT_DECREMENT))
 252                 return -EINVAL;
 253
 254         result = acpi_bus_get_device(handle, &device);
 255         if (result)
 256                 return result;
 257
 258         pr = acpi_driver_data(device);
 259         if (!pr)
 260                 return -ENODEV;
 261
 262         /* Thermal limits are always relative to the current Px/Tx state. */
 263         if (pr->flags.throttling)
 264                 pr->limit.thermal.tx = pr->throttling.state;
 265
 266         /*
 267          * Our default policy is to only use throttling at the lowest
 268          * performance state.
 269          */
 270
 271         tx = pr->limit.thermal.tx;
 272
 273         switch (type) {
 274
 275         case ACPI_PROCESSOR_LIMIT_NONE:
 276                 do {
 277                         result = acpi_thermal_cpufreq_decrease(pr->id);
 278                 } while (!result);
 279                 tx = 0;
 280                 break;
 281
 282         case ACPI_PROCESSOR_LIMIT_INCREMENT:
 283                 /* if going up: P-states first, T-states later */
 284
 285                 result = acpi_thermal_cpufreq_increase(pr->id);
 286                 if (!result)
 287                         goto end;
 288                 else if (result == -ERANGE)
 289                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 290                                           "At maximum performance state\n"));
 291
 292                 if (pr->flags.throttling) {
 293                         if (tx == (pr->throttling.state_count - 1))
 294                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 295                                                   "At maximum throttling state\n"));
 296                         else
 297                                 tx++;
 298                 }
 299                 break;
 300
 301         case ACPI_PROCESSOR_LIMIT_DECREMENT:
 302                 /* if going down: T-states first, P-states later */
 303
 304                 if (pr->flags.throttling) {
 305                         if (tx == 0) {
 306                                 max_tx_px = 1;
 307                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 308                                                   "At minimum throttling state\n"));
 309                         } else {
 310                                 tx--;
 311                                 goto end;
 312                         }
 313                 }
 314
 315                 result = acpi_thermal_cpufreq_decrease(pr->id);
 316                 if (result) {
 317                         /*
 318                          * We only could get -ERANGE, 1 or 0.
 319                          * In the first two cases we reached max freq again.
 320                          */
 321                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 322                                           "At minimum performance state\n"));
 323                         max_tx_px = 1;
 324                 } else
 325                         max_tx_px = 0;
 326
 327                 break;
 328         }
 329
 330       end:
 331         if (pr->flags.throttling) {
 332                 pr->limit.thermal.px = 0;
 333                 pr->limit.thermal.tx = tx;
 334
 335                 result = acpi_processor_apply_limit(pr);
 336                 if (result)
 337                         printk(KERN_ERR PREFIX "Unable to set thermal limit\n");
 338
 339                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Thermal limit now (P%d:T%d)\n",
 340                                   pr->limit.thermal.px, pr->limit.thermal.tx));
 341         } else
 342                 result = 0;
 343         if (max_tx_px)
 344                 return 1;
 345         else
 346                 return result;
 347 }
 348
 349 int acpi_processor_get_limit_info(struct acpi_processor *pr)
 350 {
 351
 352         if (!pr)
 353                 return -EINVAL;
 354
 355         if (pr->flags.throttling)
 356                 pr->flags.limit = 1;
 357
 358         return 0;
 359 }
 360
 361 /* thermal coolign device callbacks */
 362 static int acpi_processor_max_state(struct acpi_processor *pr)
 363 {
 364         int max_state = 0;
 365
 366         /*
 367          * There exists four states according to
 368          * cpufreq_thermal_reduction_ptg. 0, 1, 2, 3
 369          */
 370         max_state += cpufreq_get_max_state(pr->id);
 371         if (pr->flags.throttling)
 372                 max_state += (pr->throttling.state_count -1);
 373
 374         return max_state;
 375 }
 376 static int
 377 processor_get_max_state(struct thermal_cooling_device *cdev, char *buf)
 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         return sprintf(buf, "%d\n", acpi_processor_max_state(pr));
 386 }
 387
 388 static int
 389 processor_get_cur_state(struct thermal_cooling_device *cdev, char *buf)
 390 {
 391         struct acpi_device *device = cdev->devdata;
 392         struct acpi_processor *pr = acpi_driver_data(device);
 393         int cur_state;
 394
 395         if (!device || !pr)
 396                 return -EINVAL;
 397
 398         cur_state = cpufreq_get_cur_state(pr->id);
 399         if (pr->flags.throttling)
 400                 cur_state += pr->throttling.state;
 401
 402         return sprintf(buf, "%d\n", cur_state);
 403 }
 404
 405 static int
 406 processor_set_cur_state(struct thermal_cooling_device *cdev, unsigned int state)
 407 {
 408         struct acpi_device *device = cdev->devdata;
 409         struct acpi_processor *pr = acpi_driver_data(device);
 410         int result = 0;
 411         int max_pstate;
 412
 413         if (!device || !pr)
 414                 return -EINVAL;
 415
 416         max_pstate = cpufreq_get_max_state(pr->id);
 417
 418         if (state > acpi_processor_max_state(pr))
 419                 return -EINVAL;
 420
 421         if (state <= max_pstate) {
 422                 if (pr->flags.throttling && pr->throttling.state)
 423                         result = acpi_processor_set_throttling(pr, 0);
 424                 cpufreq_set_cur_state(pr->id, state);
 425         } else {
 426                 cpufreq_set_cur_state(pr->id, max_pstate);
 427                 result = acpi_processor_set_throttling(pr,
 428                                 state - max_pstate);
 429         }
 430         return result;
 431 }
 432
 433 struct thermal_cooling_device_ops processor_cooling_ops = {
 434         .get_max_state = processor_get_max_state,
 435         .get_cur_state = processor_get_cur_state,
 436         .set_cur_state = processor_set_cur_state,
 437 };
 438
 439 /* /proc interface */
 440
 441 static int acpi_processor_limit_seq_show(struct seq_file *seq, void *offset)
 442 {
 443         struct acpi_processor *pr = (struct acpi_processor *)seq->private;
 444
 445
 446         if (!pr)
 447                 goto end;
 448
 449         if (!pr->flags.limit) {
 450                 seq_puts(seq, "<not supported>\n");
 451                 goto end;
 452         }
 453
 454         seq_printf(seq, "active limit:            P%d:T%d\n"
 455                    "user limit:              P%d:T%d\n"
 456                    "thermal limit:           P%d:T%d\n",
 457                    pr->limit.state.px, pr->limit.state.tx,
 458                    pr->limit.user.px, pr->limit.user.tx,
 459                    pr->limit.thermal.px, pr->limit.thermal.tx);
 460
 461       end:
 462         return 0;
 463 }
 464
 465 static int acpi_processor_limit_open_fs(struct inode *inode, struct file *file)
 466 {
 467         return single_open(file, acpi_processor_limit_seq_show,
 468                            PDE(inode)->data);
 469 }
 470
 471 static ssize_t acpi_processor_write_limit(struct file * file,
 472                                           const char __user * buffer,
 473                                           size_t count, loff_t * data)
 474 {
 475         int result = 0;
 476         struct seq_file *m = file->private_data;
 477         struct acpi_processor *pr = m->private;
 478         char limit_string[25] = { '\0' };
 479         int px = 0;
 480         int tx = 0;
 481
 482
 483         if (!pr || (count > sizeof(limit_string) - 1)) {
 484                 return -EINVAL;
 485         }
 486
 487         if (copy_from_user(limit_string, buffer, count)) {
 488                 return -EFAULT;
 489         }
 490
 491         limit_string[count] = '\0';
 492
 493         if (sscanf(limit_string, "%d:%d", &px, &tx) != 2) {
 494                 printk(KERN_ERR PREFIX "Invalid data format\n");
 495                 return -EINVAL;
 496         }
 497
 498         if (pr->flags.throttling) {
 499                 if ((tx < 0) || (tx > (pr->throttling.state_count - 1))) {
 500                         printk(KERN_ERR PREFIX "Invalid tx\n");
 501                         return -EINVAL;
 502                 }
 503                 pr->limit.user.tx = tx;
 504         }
 505
 506         result = acpi_processor_apply_limit(pr);
 507
 508         return count;
 509 }
 510
 511 struct file_operations acpi_processor_limit_fops = {
 512         .owner = THIS_MODULE,
 513         .open = acpi_processor_limit_open_fs,
 514         .read = seq_read,
 515         .write = acpi_processor_write_limit,
 516         .llseek = seq_lseek,
 517         .release = single_release,
 518 };