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
  36 #include <asm/uaccess.h>
  37
  38 #include <acpi/acpi_bus.h>
  39 #include <acpi/processor.h>
  40 #include <acpi/acpi_drivers.h>
  41
  42 #define ACPI_PROCESSOR_COMPONENT        0x01000000
  43 #define ACPI_PROCESSOR_CLASS            "processor"
  44 #define ACPI_PROCESSOR_DRIVER_NAME      "ACPI Processor Driver"
  45 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  46 ACPI_MODULE_NAME                ("acpi_processor")
  47
  48
  49 /* --------------------------------------------------------------------------
  50                                  Limit Interface
  51    -------------------------------------------------------------------------- */
  52
  53 static int
  54 acpi_processor_apply_limit (
  55         struct acpi_processor*  pr)
  56 {
  57         int                     result = 0;
  58         u16                     px = 0;
  59         u16                     tx = 0;
  60
  61         ACPI_FUNCTION_TRACE("acpi_processor_apply_limit");
  62
  63         if (!pr)
  64                 return_VALUE(-EINVAL);
  65
  66         if (!pr->flags.limit)
  67                 return_VALUE(-ENODEV);
  68
  69         if (pr->flags.throttling) {
  70                 if (pr->limit.user.tx > tx)
  71                         tx = pr->limit.user.tx;
  72                 if (pr->limit.thermal.tx > tx)
  73                         tx = pr->limit.thermal.tx;
  74
  75                 result = acpi_processor_set_throttling(pr, tx);
  76                 if (result)
  77                         goto end;
  78         }
  79
  80         pr->limit.state.px = px;
  81         pr->limit.state.tx = tx;
  82
  83         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor [%d] limit set to (P%d:T%d)\n",
  84                 pr->id,
  85                 pr->limit.state.px,
  86                 pr->limit.state.tx));
  87
  88 end:
  89         if (result)
  90                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unable to set limit\n"));
  91
  92         return_VALUE(result);
  93 }
  94
  95
  96 #ifdef CONFIG_CPU_FREQ
  97
  98 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it
  99  * offers (in most cases) voltage scaling in addition to frequency scaling, and
 100  * thus a cubic (instead of linear) reduction of energy. Also, we allow for
 101  * _any_ cpufreq driver and not only the acpi-cpufreq driver.
 102  */
 103
 104 static unsigned int cpufreq_thermal_reduction_pctg[NR_CPUS];
 105 static unsigned int acpi_thermal_cpufreq_is_init = 0;
 106
 107
 108 static int cpu_has_cpufreq(unsigned int cpu)
 109 {
 110         struct cpufreq_policy policy;
 111         if (!acpi_thermal_cpufreq_is_init)
 112                 return -ENODEV;
 113         if (!cpufreq_get_policy(&policy, cpu))
 114                 return -ENODEV;
 115         return 0;
 116 }
 117
 118
 119 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
 120 {
 121         if (!cpu_has_cpufreq(cpu))
 122                 return -ENODEV;
 123
 124         if (cpufreq_thermal_reduction_pctg[cpu] < 60) {
 125                 cpufreq_thermal_reduction_pctg[cpu] += 20;
 126                 cpufreq_update_policy(cpu);
 127                 return 0;
 128         }
 129
 130         return -ERANGE;
 131 }
 132
 133
 134 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
 135 {
 136         if (!cpu_has_cpufreq(cpu))
 137                 return -ENODEV;
 138
 139         if (cpufreq_thermal_reduction_pctg[cpu] >= 20) {
 140                 cpufreq_thermal_reduction_pctg[cpu] -= 20;
 141                 cpufreq_update_policy(cpu);
 142                 return 0;
 143         }
 144
 145         return -ERANGE;
 146 }
 147
 148
 149 static int acpi_thermal_cpufreq_notifier(
 150         struct notifier_block *nb,
 151         unsigned long event,
 152         void *data)
 153 {
 154         struct cpufreq_policy *policy = data;
 155         unsigned long max_freq = 0;
 156
 157         if (event != CPUFREQ_ADJUST)
 158                 goto out;
 159
 160         max_freq = (policy->cpuinfo.max_freq * (100 - cpufreq_thermal_reduction_pctg[policy->cpu])) / 100;
 161
 162         cpufreq_verify_within_limits(policy, 0, max_freq);
 163
 164  out:
 165         return 0;
 166 }
 167
 168
 169 static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
 170         .notifier_call = acpi_thermal_cpufreq_notifier,
 171 };
 172
 173
 174 void acpi_thermal_cpufreq_init(void) {
 175         int i;
 176
 177         for (i=0; i<NR_CPUS; i++)
 178                 cpufreq_thermal_reduction_pctg[i] = 0;
 179
 180         i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block, CPUFREQ_POLICY_NOTIFIER);
 181         if (!i)
 182                 acpi_thermal_cpufreq_is_init = 1;
 183 }
 184
 185 void acpi_thermal_cpufreq_exit(void) {
 186         if (acpi_thermal_cpufreq_is_init)
 187                 cpufreq_unregister_notifier(&acpi_thermal_cpufreq_notifier_block, CPUFREQ_POLICY_NOTIFIER);
 188
 189         acpi_thermal_cpufreq_is_init = 0;
 190 }
 191
 192 #else /* ! CONFIG_CPU_FREQ */
 193
 194 static int acpi_thermal_cpufreq_increase(unsigned int cpu) { return -ENODEV; }
 195 static int acpi_thermal_cpufreq_decrease(unsigned int cpu) { return -ENODEV; }
 196
 197
 198 #endif
 199
 200
 201 int
 202 acpi_processor_set_thermal_limit (
 203         acpi_handle             handle,
 204         int                     type)
 205 {
 206         int                     result = 0;
 207         struct acpi_processor   *pr = NULL;
 208         struct acpi_device      *device = NULL;
 209         int                     tx = 0;
 210
 211         ACPI_FUNCTION_TRACE("acpi_processor_set_thermal_limit");
 212
 213         if ((type < ACPI_PROCESSOR_LIMIT_NONE)
 214                 || (type > ACPI_PROCESSOR_LIMIT_DECREMENT))
 215                 return_VALUE(-EINVAL);
 216
 217         result = acpi_bus_get_device(handle, &device);
 218         if (result)
 219                 return_VALUE(result);
 220
 221         pr = (struct acpi_processor *) acpi_driver_data(device);
 222         if (!pr)
 223                 return_VALUE(-ENODEV);
 224
 225         /* Thermal limits are always relative to the current Px/Tx state. */
 226         if (pr->flags.throttling)
 227                 pr->limit.thermal.tx = pr->throttling.state;
 228
 229         /*
 230          * Our default policy is to only use throttling at the lowest
 231          * performance state.
 232          */
 233
 234         tx = pr->limit.thermal.tx;
 235
 236         switch (type) {
 237
 238         case ACPI_PROCESSOR_LIMIT_NONE:
 239                 do {
 240                         result = acpi_thermal_cpufreq_decrease(pr->id);
 241                 } while (!result);
 242                 tx = 0;
 243                 break;
 244
 245         case ACPI_PROCESSOR_LIMIT_INCREMENT:
 246                 /* if going up: P-states first, T-states later */
 247
 248                 result = acpi_thermal_cpufreq_increase(pr->id);
 249                 if (!result)
 250                         goto end;
 251                 else if (result == -ERANGE)
 252                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 253                                         "At maximum performance state\n"));
 254
 255                 if (pr->flags.throttling) {
 256                         if (tx == (pr->throttling.state_count - 1))
 257                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 258                                         "At maximum throttling state\n"));
 259                         else
 260                                 tx++;
 261                 }
 262                 break;
 263
 264         case ACPI_PROCESSOR_LIMIT_DECREMENT:
 265                 /* if going down: T-states first, P-states later */
 266
 267                 if (pr->flags.throttling) {
 268                         if (tx == 0)
 269                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 270                                         "At minimum throttling state\n"));
 271                         else {
 272                                 tx--;
 273                                 goto end;
 274                         }
 275                 }
 276
 277                 result = acpi_thermal_cpufreq_decrease(pr->id);
 278                 if (result == -ERANGE)
 279                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 280                                         "At minimum performance state\n"));
 281
 282                 break;
 283         }
 284
 285 end:
 286         if (pr->flags.throttling) {
 287                 pr->limit.thermal.px = 0;
 288                 pr->limit.thermal.tx = tx;
 289
 290                 result = acpi_processor_apply_limit(pr);
 291                 if (result)
 292                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 293                                           "Unable to set thermal limit\n"));
 294
 295                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Thermal limit now (P%d:T%d)\n",
 296                                   pr->limit.thermal.px,
 297                                   pr->limit.thermal.tx));
 298         } else
 299                 result = 0;
 300
 301         return_VALUE(result);
 302 }
 303
 304
 305 int
 306 acpi_processor_get_limit_info (
 307         struct acpi_processor   *pr)
 308 {
 309         ACPI_FUNCTION_TRACE("acpi_processor_get_limit_info");
 310
 311         if (!pr)
 312                 return_VALUE(-EINVAL);
 313
 314         if (pr->flags.throttling)
 315                 pr->flags.limit = 1;
 316
 317         return_VALUE(0);
 318 }
 319
 320
 321 /* /proc interface */
 322
 323 static int acpi_processor_limit_seq_show(struct seq_file *seq, void *offset)
 324 {
 325         struct acpi_processor   *pr = (struct acpi_processor *)seq->private;
 326
 327         ACPI_FUNCTION_TRACE("acpi_processor_limit_seq_show");
 328
 329         if (!pr)
 330                 goto end;
 331
 332         if (!pr->flags.limit) {
 333                 seq_puts(seq, "<not supported>\n");
 334                 goto end;
 335         }
 336
 337         seq_printf(seq, "active limit:            P%d:T%d\n"
 338                         "user limit:              P%d:T%d\n"
 339                         "thermal limit:           P%d:T%d\n",
 340                         pr->limit.state.px, pr->limit.state.tx,
 341                         pr->limit.user.px, pr->limit.user.tx,
 342                         pr->limit.thermal.px, pr->limit.thermal.tx);
 343
 344 end:
 345         return_VALUE(0);
 346 }
 347
 348 static int acpi_processor_limit_open_fs(struct inode *inode, struct file *file)
 349 {
 350         return single_open(file, acpi_processor_limit_seq_show,
 351                                                 PDE(inode)->data);
 352 }
 353
 354 ssize_t acpi_processor_write_limit (
 355         struct file             *file,
 356         const char              __user *buffer,
 357         size_t                  count,
 358         loff_t                  *data)
 359 {
 360         int                     result = 0;
 361         struct seq_file         *m = (struct seq_file *)file->private_data;
 362         struct acpi_processor   *pr = (struct acpi_processor *)m->private;
 363         char                    limit_string[25] = {'\0'};
 364         int                     px = 0;
 365         int                     tx = 0;
 366
 367         ACPI_FUNCTION_TRACE("acpi_processor_write_limit");
 368
 369         if (!pr || (count > sizeof(limit_string) - 1)) {
 370                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid argument\n"));
 371                 return_VALUE(-EINVAL);
 372         }
 373
 374         if (copy_from_user(limit_string, buffer, count)) {
 375                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid data\n"));
 376                 return_VALUE(-EFAULT);
 377         }
 378
 379         limit_string[count] = '\0';
 380
 381         if (sscanf(limit_string, "%d:%d", &px, &tx) != 2) {
 382                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid data format\n"));
 383                 return_VALUE(-EINVAL);
 384         }
 385
 386         if (pr->flags.throttling) {
 387                 if ((tx < 0) || (tx > (pr->throttling.state_count - 1))) {
 388                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid tx\n"));
 389                         return_VALUE(-EINVAL);
 390                 }
 391                 pr->limit.user.tx = tx;
 392         }
 393
 394         result = acpi_processor_apply_limit(pr);
 395
 396         return_VALUE(count);
 397 }
 398
 399
 400 struct file_operations acpi_processor_limit_fops = {
 401         .open           = acpi_processor_limit_open_fs,
 402         .read           = seq_read,
 403         .llseek         = seq_lseek,
 404         .release        = single_release,
 405 };
 406