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 unsigned int cpufreq_thermal_reduction_pctg[NR_CPUS];
 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 (cpufreq_thermal_reduction_pctg[cpu] <
 117                 CPUFREQ_THERMAL_MAX_STEP) {
 118                 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 (cpufreq_thermal_reduction_pctg[cpu] >
 132                 (CPUFREQ_THERMAL_MIN_STEP + 1))
 133                 cpufreq_thermal_reduction_pctg[cpu]--;
 134         else
 135                 cpufreq_thermal_reduction_pctg[cpu] = 0;
 136         cpufreq_update_policy(cpu);
 137         /* We reached max freq again and can leave passive mode */
 138         return !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 - cpufreq_thermal_reduction_pctg[policy->cpu] * 20)) / 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 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         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_CPUS; i++)
 195                 cpufreq_thermal_reduction_pctg[i] = 0;
 196
 197         i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
 198                                       CPUFREQ_POLICY_NOTIFIER);
 199         if (!i)
 200                 acpi_thermal_cpufreq_is_init = 1;
 201 }
 202
 203 void acpi_thermal_cpufreq_exit(void)
 204 {
 205         if (acpi_thermal_cpufreq_is_init)
 206                 cpufreq_unregister_notifier
 207                     (&acpi_thermal_cpufreq_notifier_block,
 208                      CPUFREQ_POLICY_NOTIFIER);
 209
 210         acpi_thermal_cpufreq_is_init = 0;
 211 }
 212
 213 #else                           /* ! CONFIG_CPU_FREQ */
 214 static int cpufreq_get_max_state(unsigned int cpu)
 215 {
 216         return 0;
 217 }
 218
 219 static int cpufreq_get_cur_state(unsigned int cpu)
 220 {
 221         return 0;
 222 }
 223
 224 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 225 {
 226         return 0;
 227 }
 228
 229 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
 230 {
 231         return -ENODEV;
 232 }
 233 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
 234 {
 235         return -ENODEV;
 236 }
 237
 238 #endif
 239
 240 int acpi_processor_set_thermal_limit(acpi_handle handle, int type)
 241 {
 242         int result = 0;
 243         struct acpi_processor *pr = NULL;
 244         struct acpi_device *device = NULL;
 245         int tx = 0, max_tx_px = 0;
 246
 247
 248         if ((type < ACPI_PROCESSOR_LIMIT_NONE)
 249             || (type > ACPI_PROCESSOR_LIMIT_DECREMENT))
 250                 return -EINVAL;
 251
 252         result = acpi_bus_get_device(handle, &device);
 253         if (result)
 254                 return result;
 255
 256         pr = acpi_driver_data(device);
 257         if (!pr)
 258                 return -ENODEV;
 259
 260         /* Thermal limits are always relative to the current Px/Tx state. */
 261         if (pr->flags.throttling)
 262                 pr->limit.thermal.tx = pr->throttling.state;
 263
 264         /*
 265          * Our default policy is to only use throttling at the lowest
 266          * performance state.
 267          */
 268
 269         tx = pr->limit.thermal.tx;
 270
 271         switch (type) {
 272
 273         case ACPI_PROCESSOR_LIMIT_NONE:
 274                 do {
 275                         result = acpi_thermal_cpufreq_decrease(pr->id);
 276                 } while (!result);
 277                 tx = 0;
 278                 break;
 279
 280         case ACPI_PROCESSOR_LIMIT_INCREMENT:
 281                 /* if going up: P-states first, T-states later */
 282
 283                 result = acpi_thermal_cpufreq_increase(pr->id);
 284                 if (!result)
 285                         goto end;
 286                 else if (result == -ERANGE)
 287                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 288                                           "At maximum performance state\n"));
 289
 290                 if (pr->flags.throttling) {
 291                         if (tx == (pr->throttling.state_count - 1))
 292                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 293                                                   "At maximum throttling state\n"));
 294                         else
 295                                 tx++;
 296                 }
 297                 break;
 298
 299         case ACPI_PROCESSOR_LIMIT_DECREMENT:
 300                 /* if going down: T-states first, P-states later */
 301
 302                 if (pr->flags.throttling) {
 303                         if (tx == 0) {
 304                                 max_tx_px = 1;
 305                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 306                                                   "At minimum throttling state\n"));
 307                         } else {
 308                                 tx--;
 309                                 goto end;
 310                         }
 311                 }
 312
 313                 result = acpi_thermal_cpufreq_decrease(pr->id);
 314                 if (result) {
 315                         /*
 316                          * We only could get -ERANGE, 1 or 0.
 317                          * In the first two cases we reached max freq again.
 318                          */
 319                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 320                                           "At minimum performance state\n"));
 321                         max_tx_px = 1;
 322                 } else
 323                         max_tx_px = 0;
 324
 325                 break;
 326         }
 327
 328       end:
 329         if (pr->flags.throttling) {
 330                 pr->limit.thermal.px = 0;
 331                 pr->limit.thermal.tx = tx;
 332
 333                 result = acpi_processor_apply_limit(pr);
 334                 if (result)
 335                         printk(KERN_ERR PREFIX "Unable to set thermal limit\n");
 336
 337                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Thermal limit now (P%d:T%d)\n",
 338                                   pr->limit.thermal.px, pr->limit.thermal.tx));
 339         } else
 340                 result = 0;
 341         if (max_tx_px)
 342                 return 1;
 343         else
 344                 return result;
 345 }
 346
 347 int acpi_processor_get_limit_info(struct acpi_processor *pr)
 348 {
 349
 350         if (!pr)
 351                 return -EINVAL;
 352
 353         if (pr->flags.throttling)
 354                 pr->flags.limit = 1;
 355
 356         return 0;
 357 }
 358
 359 /* thermal coolign device callbacks */
 360 static int acpi_processor_max_state(struct acpi_processor *pr)
 361 {
 362         int max_state = 0;
 363
 364         /*
 365          * There exists four states according to
 366          * cpufreq_thermal_reduction_ptg. 0, 1, 2, 3
 367          */
 368         max_state += cpufreq_get_max_state(pr->id);
 369         if (pr->flags.throttling)
 370                 max_state += (pr->throttling.state_count -1);
 371
 372         return max_state;
 373 }
 374 static int
 375 processor_get_max_state(struct thermal_cooling_device *cdev, char *buf)
 376 {
 377         struct acpi_device *device = cdev->devdata;
 378         struct acpi_processor *pr = acpi_driver_data(device);
 379
 380         if (!device || !pr)
 381                 return -EINVAL;
 382
 383         return sprintf(buf, "%d\n", acpi_processor_max_state(pr));
 384 }
 385
 386 static int
 387 processor_get_cur_state(struct thermal_cooling_device *cdev, char *buf)
 388 {
 389         struct acpi_device *device = cdev->devdata;
 390         struct acpi_processor *pr = acpi_driver_data(device);
 391         int cur_state;
 392
 393         if (!device || !pr)
 394                 return -EINVAL;
 395
 396         cur_state = cpufreq_get_cur_state(pr->id);
 397         if (pr->flags.throttling)
 398                 cur_state += pr->throttling.state;
 399
 400         return sprintf(buf, "%d\n", cur_state);
 401 }
 402
 403 static int
 404 processor_set_cur_state(struct thermal_cooling_device *cdev, unsigned int state)
 405 {
 406         struct acpi_device *device = cdev->devdata;
 407         struct acpi_processor *pr = acpi_driver_data(device);
 408         int result = 0;
 409         int max_pstate;
 410
 411         if (!device || !pr)
 412                 return -EINVAL;
 413
 414         max_pstate = cpufreq_get_max_state(pr->id);
 415
 416         if (state > acpi_processor_max_state(pr))
 417                 return -EINVAL;
 418
 419         if (state <= max_pstate) {
 420                 if (pr->flags.throttling && pr->throttling.state)
 421                         result = acpi_processor_set_throttling(pr, 0);
 422                 cpufreq_set_cur_state(pr->id, state);
 423         } else {
 424                 cpufreq_set_cur_state(pr->id, max_pstate);
 425                 result = acpi_processor_set_throttling(pr,
 426                                 state - max_pstate);
 427         }
 428         return result;
 429 }
 430
 431 struct thermal_cooling_device_ops processor_cooling_ops = {
 432         .get_max_state = processor_get_max_state,
 433         .get_cur_state = processor_get_cur_state,
 434         .set_cur_state = processor_set_cur_state,
 435 };
 436
 437 /* /proc interface */
 438
 439 static int acpi_processor_limit_seq_show(struct seq_file *seq, void *offset)
 440 {
 441         struct acpi_processor *pr = (struct acpi_processor *)seq->private;
 442
 443
 444         if (!pr)
 445                 goto end;
 446
 447         if (!pr->flags.limit) {
 448                 seq_puts(seq, "<not supported>\n");
 449                 goto end;
 450         }
 451
 452         seq_printf(seq, "active limit:            P%d:T%d\n"
 453                    "user limit:              P%d:T%d\n"
 454                    "thermal limit:           P%d:T%d\n",
 455                    pr->limit.state.px, pr->limit.state.tx,
 456                    pr->limit.user.px, pr->limit.user.tx,
 457                    pr->limit.thermal.px, pr->limit.thermal.tx);
 458
 459       end:
 460         return 0;
 461 }
 462
 463 static int acpi_processor_limit_open_fs(struct inode *inode, struct file *file)
 464 {
 465         return single_open(file, acpi_processor_limit_seq_show,
 466                            PDE(inode)->data);
 467 }
 468
 469 static ssize_t acpi_processor_write_limit(struct file * file,
 470                                           const char __user * buffer,
 471                                           size_t count, loff_t * data)
 472 {
 473         int result = 0;
 474         struct seq_file *m = file->private_data;
 475         struct acpi_processor *pr = m->private;
 476         char limit_string[25] = { '\0' };
 477         int px = 0;
 478         int tx = 0;
 479
 480
 481         if (!pr || (count > sizeof(limit_string) - 1)) {
 482                 return -EINVAL;
 483         }
 484
 485         if (copy_from_user(limit_string, buffer, count)) {
 486                 return -EFAULT;
 487         }
 488
 489         limit_string[count] = '\0';
 490
 491         if (sscanf(limit_string, "%d:%d", &px, &tx) != 2) {
 492                 printk(KERN_ERR PREFIX "Invalid data format\n");
 493                 return -EINVAL;
 494         }
 495
 496         if (pr->flags.throttling) {
 497                 if ((tx < 0) || (tx > (pr->throttling.state_count - 1))) {
 498                         printk(KERN_ERR PREFIX "Invalid tx\n");
 499                         return -EINVAL;
 500                 }
 501                 pr->limit.user.tx = tx;
 502         }
 503
 504         result = acpi_processor_apply_limit(pr);
 505
 506         return count;
 507 }
 508
 509 struct file_operations acpi_processor_limit_fops = {
 510         .open = acpi_processor_limit_open_fs,
 511         .read = seq_read,
 512         .write = acpi_processor_write_limit,
 513         .llseek = seq_lseek,
 514         .release = single_release,
 515 };