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                                  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         ACPI_FUNCTION_TRACE("acpi_processor_apply_limit");
  58
  59         if (!pr)
  60                 return_VALUE(-EINVAL);
  61
  62         if (!pr->flags.limit)
  63                 return_VALUE(-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);
  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                 ACPI_ERROR((AE_INFO, "Unable to set limit"));
  86
  87         return_VALUE(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 static unsigned int cpufreq_thermal_reduction_pctg[NR_CPUS];
  99 static unsigned int acpi_thermal_cpufreq_is_init = 0;
 100
 101 static int cpu_has_cpufreq(unsigned int cpu)
 102 {
 103         struct cpufreq_policy policy;
 104         if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu))
 105                 return 0;
 106         return 1;
 107 }
 108
 109 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
 110 {
 111         if (!cpu_has_cpufreq(cpu))
 112                 return -ENODEV;
 113
 114         if (cpufreq_thermal_reduction_pctg[cpu] < 60) {
 115                 cpufreq_thermal_reduction_pctg[cpu] += 20;
 116                 cpufreq_update_policy(cpu);
 117                 return 0;
 118         }
 119
 120         return -ERANGE;
 121 }
 122
 123 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
 124 {
 125         if (!cpu_has_cpufreq(cpu))
 126                 return -ENODEV;
 127
 128         if (cpufreq_thermal_reduction_pctg[cpu] > 20)
 129                 cpufreq_thermal_reduction_pctg[cpu] -= 20;
 130         else
 131                 cpufreq_thermal_reduction_pctg[cpu] = 0;
 132         cpufreq_update_policy(cpu);
 133         /* We reached max freq again and can leave passive mode */
 134         return !cpufreq_thermal_reduction_pctg[cpu];
 135 }
 136
 137 static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
 138                                          unsigned long event, void *data)
 139 {
 140         struct cpufreq_policy *policy = data;
 141         unsigned long max_freq = 0;
 142
 143         if (event != CPUFREQ_ADJUST)
 144                 goto out;
 145
 146         max_freq =
 147             (policy->cpuinfo.max_freq *
 148              (100 - cpufreq_thermal_reduction_pctg[policy->cpu])) / 100;
 149
 150         cpufreq_verify_within_limits(policy, 0, max_freq);
 151
 152       out:
 153         return 0;
 154 }
 155
 156 static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
 157         .notifier_call = acpi_thermal_cpufreq_notifier,
 158 };
 159
 160 void acpi_thermal_cpufreq_init(void)
 161 {
 162         int i;
 163
 164         for (i = 0; i < NR_CPUS; i++)
 165                 cpufreq_thermal_reduction_pctg[i] = 0;
 166
 167         i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
 168                                       CPUFREQ_POLICY_NOTIFIER);
 169         if (!i)
 170                 acpi_thermal_cpufreq_is_init = 1;
 171 }
 172
 173 void acpi_thermal_cpufreq_exit(void)
 174 {
 175         if (acpi_thermal_cpufreq_is_init)
 176                 cpufreq_unregister_notifier
 177                     (&acpi_thermal_cpufreq_notifier_block,
 178                      CPUFREQ_POLICY_NOTIFIER);
 179
 180         acpi_thermal_cpufreq_is_init = 0;
 181 }
 182
 183 #else                           /* ! CONFIG_CPU_FREQ */
 184
 185 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
 186 {
 187         return -ENODEV;
 188 }
 189 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
 190 {
 191         return -ENODEV;
 192 }
 193
 194 #endif
 195
 196 int acpi_processor_set_thermal_limit(acpi_handle handle, int type)
 197 {
 198         int result = 0;
 199         struct acpi_processor *pr = NULL;
 200         struct acpi_device *device = NULL;
 201         int tx = 0, max_tx_px = 0;
 202
 203         ACPI_FUNCTION_TRACE("acpi_processor_set_thermal_limit");
 204
 205         if ((type < ACPI_PROCESSOR_LIMIT_NONE)
 206             || (type > ACPI_PROCESSOR_LIMIT_DECREMENT))
 207                 return_VALUE(-EINVAL);
 208
 209         result = acpi_bus_get_device(handle, &device);
 210         if (result)
 211                 return_VALUE(result);
 212
 213         pr = (struct acpi_processor *)acpi_driver_data(device);
 214         if (!pr)
 215                 return_VALUE(-ENODEV);
 216
 217         /* Thermal limits are always relative to the current Px/Tx state. */
 218         if (pr->flags.throttling)
 219                 pr->limit.thermal.tx = pr->throttling.state;
 220
 221         /*
 222          * Our default policy is to only use throttling at the lowest
 223          * performance state.
 224          */
 225
 226         tx = pr->limit.thermal.tx;
 227
 228         switch (type) {
 229
 230         case ACPI_PROCESSOR_LIMIT_NONE:
 231                 do {
 232                         result = acpi_thermal_cpufreq_decrease(pr->id);
 233                 } while (!result);
 234                 tx = 0;
 235                 break;
 236
 237         case ACPI_PROCESSOR_LIMIT_INCREMENT:
 238                 /* if going up: P-states first, T-states later */
 239
 240                 result = acpi_thermal_cpufreq_increase(pr->id);
 241                 if (!result)
 242                         goto end;
 243                 else if (result == -ERANGE)
 244                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 245                                           "At maximum performance state\n"));
 246
 247                 if (pr->flags.throttling) {
 248                         if (tx == (pr->throttling.state_count - 1))
 249                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 250                                                   "At maximum throttling state\n"));
 251                         else
 252                                 tx++;
 253                 }
 254                 break;
 255
 256         case ACPI_PROCESSOR_LIMIT_DECREMENT:
 257                 /* if going down: T-states first, P-states later */
 258
 259                 if (pr->flags.throttling) {
 260                         if (tx == 0) {
 261                                 max_tx_px = 1;
 262                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 263                                                   "At minimum throttling state\n"));
 264                         } else {
 265                                 tx--;
 266                                 goto end;
 267                         }
 268                 }
 269
 270                 result = acpi_thermal_cpufreq_decrease(pr->id);
 271                 if (result) {
 272                         /*
 273                          * We only could get -ERANGE, 1 or 0.
 274                          * In the first two cases we reached max freq again.
 275                          */
 276                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 277                                           "At minimum performance state\n"));
 278                         max_tx_px = 1;
 279                 } else
 280                         max_tx_px = 0;
 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_ERROR((AE_INFO, "Unable to set thermal limit"));
 293
 294                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Thermal limit now (P%d:T%d)\n",
 295                                   pr->limit.thermal.px, pr->limit.thermal.tx));
 296         } else
 297                 result = 0;
 298         if (max_tx_px)
 299                 return_VALUE(1);
 300         else
 301                 return_VALUE(result);
 302 }
 303
 304 int acpi_processor_get_limit_info(struct acpi_processor *pr)
 305 {
 306         ACPI_FUNCTION_TRACE("acpi_processor_get_limit_info");
 307
 308         if (!pr)
 309                 return_VALUE(-EINVAL);
 310
 311         if (pr->flags.throttling)
 312                 pr->flags.limit = 1;
 313
 314         return_VALUE(0);
 315 }
 316
 317 /* /proc interface */
 318
 319 static int acpi_processor_limit_seq_show(struct seq_file *seq, void *offset)
 320 {
 321         struct acpi_processor *pr = (struct acpi_processor *)seq->private;
 322
 323         ACPI_FUNCTION_TRACE("acpi_processor_limit_seq_show");
 324
 325         if (!pr)
 326                 goto end;
 327
 328         if (!pr->flags.limit) {
 329                 seq_puts(seq, "<not supported>\n");
 330                 goto end;
 331         }
 332
 333         seq_printf(seq, "active limit:            P%d:T%d\n"
 334                    "user limit:              P%d:T%d\n"
 335                    "thermal limit:           P%d:T%d\n",
 336                    pr->limit.state.px, pr->limit.state.tx,
 337                    pr->limit.user.px, pr->limit.user.tx,
 338                    pr->limit.thermal.px, pr->limit.thermal.tx);
 339
 340       end:
 341         return_VALUE(0);
 342 }
 343
 344 static int acpi_processor_limit_open_fs(struct inode *inode, struct file *file)
 345 {
 346         return single_open(file, acpi_processor_limit_seq_show,
 347                            PDE(inode)->data);
 348 }
 349
 350 static ssize_t acpi_processor_write_limit(struct file * file,
 351                                           const char __user * buffer,
 352                                           size_t count, loff_t * data)
 353 {
 354         int result = 0;
 355         struct seq_file *m = (struct seq_file *)file->private_data;
 356         struct acpi_processor *pr = (struct acpi_processor *)m->private;
 357         char limit_string[25] = { '\0' };
 358         int px = 0;
 359         int tx = 0;
 360
 361         ACPI_FUNCTION_TRACE("acpi_processor_write_limit");
 362
 363         if (!pr || (count > sizeof(limit_string) - 1)) {
 364                 return_VALUE(-EINVAL);
 365         }
 366
 367         if (copy_from_user(limit_string, buffer, count)) {
 368                 return_VALUE(-EFAULT);
 369         }
 370
 371         limit_string[count] = '\0';
 372
 373         if (sscanf(limit_string, "%d:%d", &px, &tx) != 2) {
 374                 ACPI_ERROR((AE_INFO, "Invalid data format"));
 375                 return_VALUE(-EINVAL);
 376         }
 377
 378         if (pr->flags.throttling) {
 379                 if ((tx < 0) || (tx > (pr->throttling.state_count - 1))) {
 380                         ACPI_ERROR((AE_INFO, "Invalid tx"));
 381                         return_VALUE(-EINVAL);
 382                 }
 383                 pr->limit.user.tx = tx;
 384         }
 385
 386         result = acpi_processor_apply_limit(pr);
 387
 388         return_VALUE(count);
 389 }
 390
 391 struct file_operations acpi_processor_limit_fops = {
 392         .open = acpi_processor_limit_open_fs,
 393         .read = seq_read,
 394         .write = acpi_processor_write_limit,
 395         .llseek = seq_lseek,
 396         .release = single_release,
 397 };