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 PREFIX "ACPI: "
  44
  45 #define ACPI_PROCESSOR_CLASS            "processor"
  46 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  47 ACPI_MODULE_NAME("processor_thermal");
  48
  49 /* --------------------------------------------------------------------------
  50                                  Limit Interface
  51    -------------------------------------------------------------------------- */
  52 static int acpi_processor_apply_limit(struct acpi_processor *pr)
  53 {
  54         int result = 0;
  55         u16 px = 0;
  56         u16 tx = 0;
  57
  58
  59         if (!pr)
  60                 return -EINVAL;
  61
  62         if (!pr->flags.limit)
  63                 return -ENODEV;
  64
  65         if (pr->flags.throttling) {
  66                 if (pr->limit.user.tx > tx)
  67                         tx = pr->limit.user.tx;
  68                 if (pr->limit.thermal.tx > tx)
  69                         tx = pr->limit.thermal.tx;
  70
  71                 result = acpi_processor_set_throttling(pr, tx, false);
  72                 if (result)
  73                         goto end;
  74         }
  75
  76         pr->limit.state.px = px;
  77         pr->limit.state.tx = tx;
  78
  79         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  80                           "Processor [%d] limit set to (P%d:T%d)\n", pr->id,
  81                           pr->limit.state.px, pr->limit.state.tx));
  82
  83       end:
  84         if (result)
  85                 printk(KERN_ERR PREFIX "Unable to set limit\n");
  86
  87         return result;
  88 }
  89
  90 #ifdef CONFIG_CPU_FREQ
  91
  92 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it
  93  * offers (in most cases) voltage scaling in addition to frequency scaling, and
  94  * thus a cubic (instead of linear) reduction of energy. Also, we allow for
  95  * _any_ cpufreq driver and not only the acpi-cpufreq driver.
  96  */
  97
  98 #define CPUFREQ_THERMAL_MIN_STEP 0
  99 #define CPUFREQ_THERMAL_MAX_STEP 3
 100
 101 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
 102 static unsigned int acpi_thermal_cpufreq_is_init = 0;
 103
 104 static int cpu_has_cpufreq(unsigned int cpu)
 105 {
 106         struct cpufreq_policy policy;
 107         if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu))
 108                 return 0;
 109         return 1;
 110 }
 111
 112 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
 113 {
 114         if (!cpu_has_cpufreq(cpu))
 115                 return -ENODEV;
 116
 117         if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) <
 118                 CPUFREQ_THERMAL_MAX_STEP) {
 119                 per_cpu(cpufreq_thermal_reduction_pctg, cpu)++;
 120                 cpufreq_update_policy(cpu);
 121                 return 0;
 122         }
 123
 124         return -ERANGE;
 125 }
 126
 127 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
 128 {
 129         if (!cpu_has_cpufreq(cpu))
 130                 return -ENODEV;
 131
 132         if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) >
 133                 (CPUFREQ_THERMAL_MIN_STEP + 1))
 134                 per_cpu(cpufreq_thermal_reduction_pctg, cpu)--;
 135         else
 136                 per_cpu(cpufreq_thermal_reduction_pctg, cpu) = 0;
 137         cpufreq_update_policy(cpu);
 138         /* We reached max freq again and can leave passive mode */
 139         return !per_cpu(cpufreq_thermal_reduction_pctg, cpu);
 140 }
 141
 142 static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
 143                                          unsigned long event, void *data)
 144 {
 145         struct cpufreq_policy *policy = data;
 146         unsigned long max_freq = 0;
 147
 148         if (event != CPUFREQ_ADJUST)
 149                 goto out;
 150
 151         max_freq = (
 152             policy->cpuinfo.max_freq *
 153             (100 - per_cpu(cpufreq_thermal_reduction_pctg, policy->cpu) * 20)
 154         ) / 100;
 155
 156         cpufreq_verify_within_limits(policy, 0, max_freq);
 157
 158       out:
 159         return 0;
 160 }
 161
 162 static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
 163         .notifier_call = acpi_thermal_cpufreq_notifier,
 164 };
 165
 166 static int cpufreq_get_max_state(unsigned int cpu)
 167 {
 168         if (!cpu_has_cpufreq(cpu))
 169                 return 0;
 170
 171         return CPUFREQ_THERMAL_MAX_STEP;
 172 }
 173
 174 static int cpufreq_get_cur_state(unsigned int cpu)
 175 {
 176         if (!cpu_has_cpufreq(cpu))
 177                 return 0;
 178
 179         return per_cpu(cpufreq_thermal_reduction_pctg, cpu);
 180 }
 181
 182 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 183 {
 184         if (!cpu_has_cpufreq(cpu))
 185                 return 0;
 186
 187         per_cpu(cpufreq_thermal_reduction_pctg, cpu) = state;
 188         cpufreq_update_policy(cpu);
 189         return 0;
 190 }
 191
 192 void acpi_thermal_cpufreq_init(void)
 193 {
 194         int i;
 195
 196         for (i = 0; i < nr_cpu_ids; i++)
 197                 if (cpu_present(i))
 198                         per_cpu(cpufreq_thermal_reduction_pctg, i) = 0;
 199
 200         i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
 201                                       CPUFREQ_POLICY_NOTIFIER);
 202         if (!i)
 203                 acpi_thermal_cpufreq_is_init = 1;
 204 }
 205
 206 void acpi_thermal_cpufreq_exit(void)
 207 {
 208         if (acpi_thermal_cpufreq_is_init)
 209                 cpufreq_unregister_notifier
 210                     (&acpi_thermal_cpufreq_notifier_block,
 211                      CPUFREQ_POLICY_NOTIFIER);
 212
 213         acpi_thermal_cpufreq_is_init = 0;
 214 }
 215
 216 #else                           /* ! CONFIG_CPU_FREQ */
 217 static int cpufreq_get_max_state(unsigned int cpu)
 218 {
 219         return 0;
 220 }
 221
 222 static int cpufreq_get_cur_state(unsigned int cpu)
 223 {
 224         return 0;
 225 }
 226
 227 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 228 {
 229         return 0;
 230 }
 231
 232 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
 233 {
 234         return -ENODEV;
 235 }
 236 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
 237 {
 238         return -ENODEV;
 239 }
 240
 241 #endif
 242
 243 int acpi_processor_set_thermal_limit(acpi_handle handle, int type)
 244 {
 245         int result = 0;
 246         struct acpi_processor *pr = NULL;
 247         struct acpi_device *device = NULL;
 248         int tx = 0, max_tx_px = 0;
 249
 250
 251         if ((type < ACPI_PROCESSOR_LIMIT_NONE)
 252             || (type > ACPI_PROCESSOR_LIMIT_DECREMENT))
 253                 return -EINVAL;
 254
 255         result = acpi_bus_get_device(handle, &device);
 256         if (result)
 257                 return result;
 258
 259         pr = acpi_driver_data(device);
 260         if (!pr)
 261                 return -ENODEV;
 262
 263         /* Thermal limits are always relative to the current Px/Tx state. */
 264         if (pr->flags.throttling)
 265                 pr->limit.thermal.tx = pr->throttling.state;
 266
 267         /*
 268          * Our default policy is to only use throttling at the lowest
 269          * performance state.
 270          */
 271
 272         tx = pr->limit.thermal.tx;
 273
 274         switch (type) {
 275
 276         case ACPI_PROCESSOR_LIMIT_NONE:
 277                 do {
 278                         result = acpi_thermal_cpufreq_decrease(pr->id);
 279                 } while (!result);
 280                 tx = 0;
 281                 break;
 282
 283         case ACPI_PROCESSOR_LIMIT_INCREMENT:
 284                 /* if going up: P-states first, T-states later */
 285
 286                 result = acpi_thermal_cpufreq_increase(pr->id);
 287                 if (!result)
 288                         goto end;
 289                 else if (result == -ERANGE)
 290                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 291                                           "At maximum performance state\n"));
 292
 293                 if (pr->flags.throttling) {
 294                         if (tx == (pr->throttling.state_count - 1))
 295                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 296                                                   "At maximum throttling state\n"));
 297                         else
 298                                 tx++;
 299                 }
 300                 break;
 301
 302         case ACPI_PROCESSOR_LIMIT_DECREMENT:
 303                 /* if going down: T-states first, P-states later */
 304
 305                 if (pr->flags.throttling) {
 306                         if (tx == 0) {
 307                                 max_tx_px = 1;
 308                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 309                                                   "At minimum throttling state\n"));
 310                         } else {
 311                                 tx--;
 312                                 goto end;
 313                         }
 314                 }
 315
 316                 result = acpi_thermal_cpufreq_decrease(pr->id);
 317                 if (result) {
 318                         /*
 319                          * We only could get -ERANGE, 1 or 0.
 320                          * In the first two cases we reached max freq again.
 321                          */
 322                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 323                                           "At minimum performance state\n"));
 324                         max_tx_px = 1;
 325                 } else
 326                         max_tx_px = 0;
 327
 328                 break;
 329         }
 330
 331       end:
 332         if (pr->flags.throttling) {
 333                 pr->limit.thermal.px = 0;
 334                 pr->limit.thermal.tx = tx;
 335
 336                 result = acpi_processor_apply_limit(pr);
 337                 if (result)
 338                         printk(KERN_ERR PREFIX "Unable to set thermal limit\n");
 339
 340                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Thermal limit now (P%d:T%d)\n",
 341                                   pr->limit.thermal.px, pr->limit.thermal.tx));
 342         } else
 343                 result = 0;
 344         if (max_tx_px)
 345                 return 1;
 346         else
 347                 return result;
 348 }
 349
 350 int acpi_processor_get_limit_info(struct acpi_processor *pr)
 351 {
 352
 353         if (!pr)
 354                 return -EINVAL;
 355
 356         if (pr->flags.throttling)
 357                 pr->flags.limit = 1;
 358
 359         return 0;
 360 }
 361
 362 /* thermal coolign device callbacks */
 363 static int acpi_processor_max_state(struct acpi_processor *pr)
 364 {
 365         int max_state = 0;
 366
 367         /*
 368          * There exists four states according to
 369          * cpufreq_thermal_reduction_ptg. 0, 1, 2, 3
 370          */
 371         max_state += cpufreq_get_max_state(pr->id);
 372         if (pr->flags.throttling)
 373                 max_state += (pr->throttling.state_count -1);
 374
 375         return max_state;
 376 }
 377 static int
 378 processor_get_max_state(struct thermal_cooling_device *cdev,
 379                         unsigned long *state)
 380 {
 381         struct acpi_device *device = cdev->devdata;
 382         struct acpi_processor *pr = acpi_driver_data(device);
 383
 384         if (!device || !pr)
 385                 return -EINVAL;
 386
 387         *state = acpi_processor_max_state(pr);
 388         return 0;
 389 }
 390
 391 static int
 392 processor_get_cur_state(struct thermal_cooling_device *cdev,
 393                         unsigned long *cur_state)
 394 {
 395         struct acpi_device *device = cdev->devdata;
 396         struct acpi_processor *pr = acpi_driver_data(device);
 397
 398         if (!device || !pr)
 399                 return -EINVAL;
 400
 401         *cur_state = cpufreq_get_cur_state(pr->id);
 402         if (pr->flags.throttling)
 403                 *cur_state += pr->throttling.state;
 404         return 0;
 405 }
 406
 407 static int
 408 processor_set_cur_state(struct thermal_cooling_device *cdev,
 409                         unsigned long state)
 410 {
 411         struct acpi_device *device = cdev->devdata;
 412         struct acpi_processor *pr = acpi_driver_data(device);
 413         int result = 0;
 414         int max_pstate;
 415
 416         if (!device || !pr)
 417                 return -EINVAL;
 418
 419         max_pstate = cpufreq_get_max_state(pr->id);
 420
 421         if (state > acpi_processor_max_state(pr))
 422                 return -EINVAL;
 423
 424         if (state <= max_pstate) {
 425                 if (pr->flags.throttling && pr->throttling.state)
 426                         result = acpi_processor_set_throttling(pr, 0, false);
 427                 cpufreq_set_cur_state(pr->id, state);
 428         } else {
 429                 cpufreq_set_cur_state(pr->id, max_pstate);
 430                 result = acpi_processor_set_throttling(pr,
 431                                 state - max_pstate, false);
 432         }
 433         return result;
 434 }
 435
 436 struct thermal_cooling_device_ops processor_cooling_ops = {
 437         .get_max_state = processor_get_max_state,
 438         .get_cur_state = processor_get_cur_state,
 439         .set_cur_state = processor_set_cur_state,
 440 };
 441
 442 /* /proc interface */
 443 #ifdef CONFIG_ACPI_PROCFS
 444 static int acpi_processor_limit_seq_show(struct seq_file *seq, void *offset)
 445 {
 446         struct acpi_processor *pr = seq->private;
 447
 448         if (!pr)
 449                 goto end;
 450
 451         if (!pr->flags.limit) {
 452                 seq_puts(seq, "<not supported>\n");
 453                 goto end;
 454         }
 455
 456         seq_printf(seq, "active limit:            P%d:T%d\n"
 457                    "user limit:              P%d:T%d\n"
 458                    "thermal limit:           P%d:T%d\n",
 459                    pr->limit.state.px, pr->limit.state.tx,
 460                    pr->limit.user.px, pr->limit.user.tx,
 461                    pr->limit.thermal.px, pr->limit.thermal.tx);
 462
 463       end:
 464         return 0;
 465 }
 466
 467 static int acpi_processor_limit_open_fs(struct inode *inode, struct file *file)
 468 {
 469         return single_open(file, acpi_processor_limit_seq_show,
 470                            PDE(inode)->data);
 471 }
 472
 473 static ssize_t acpi_processor_write_limit(struct file * file,
 474                                           const char __user * buffer,
 475                                           size_t count, loff_t * data)
 476 {
 477         int result = 0;
 478         struct seq_file *m = file->private_data;
 479         struct acpi_processor *pr = m->private;
 480         char limit_string[25] = { '\0' };
 481         int px = 0;
 482         int tx = 0;
 483
 484
 485         if (!pr || (count > sizeof(limit_string) - 1)) {
 486                 return -EINVAL;
 487         }
 488
 489         if (copy_from_user(limit_string, buffer, count)) {
 490                 return -EFAULT;
 491         }
 492
 493         limit_string[count] = '\0';
 494
 495         if (sscanf(limit_string, "%d:%d", &px, &tx) != 2) {
 496                 printk(KERN_ERR PREFIX "Invalid data format\n");
 497                 return -EINVAL;
 498         }
 499
 500         if (pr->flags.throttling) {
 501                 if ((tx < 0) || (tx > (pr->throttling.state_count - 1))) {
 502                         printk(KERN_ERR PREFIX "Invalid tx\n");
 503                         return -EINVAL;
 504                 }
 505                 pr->limit.user.tx = tx;
 506         }
 507
 508         result = acpi_processor_apply_limit(pr);
 509
 510         return count;
 511 }
 512
 513 const struct file_operations acpi_processor_limit_fops = {
 514         .owner = THIS_MODULE,
 515         .open = acpi_processor_limit_open_fs,
 516         .read = seq_read,
 517         .write = acpi_processor_write_limit,
 518         .llseek = seq_lseek,
 519         .release = single_release,
 520 };
 521 #endif