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_DEBUG_PRINT((ACPI_DB_ERROR, "Unable to set limit\n"));
  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)
 105                 return -ENODEV;
 106         if (!cpufreq_get_policy(&policy, cpu))
 107                 return -ENODEV;
 108         return 0;
 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] < 60) {
 117                 cpufreq_thermal_reduction_pctg[cpu] += 20;
 118                 cpufreq_update_policy(cpu);
 119                 return 0;
 120         }
 121
 122         return -ERANGE;
 123 }
 124
 125 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
 126 {
 127         if (!cpu_has_cpufreq(cpu))
 128                 return -ENODEV;
 129
 130         if (cpufreq_thermal_reduction_pctg[cpu] >= 20) {
 131                 cpufreq_thermal_reduction_pctg[cpu] -= 20;
 132                 cpufreq_update_policy(cpu);
 133                 return 0;
 134         }
 135
 136         return -ERANGE;
 137 }
 138
 139 static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
 140                                          unsigned long event, void *data)
 141 {
 142         struct cpufreq_policy *policy = data;
 143         unsigned long max_freq = 0;
 144
 145         if (event != CPUFREQ_ADJUST)
 146                 goto out;
 147
 148         max_freq =
 149             (policy->cpuinfo.max_freq *
 150              (100 - cpufreq_thermal_reduction_pctg[policy->cpu])) / 100;
 151
 152         cpufreq_verify_within_limits(policy, 0, max_freq);
 153
 154       out:
 155         return 0;
 156 }
 157
 158 static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
 159         .notifier_call = acpi_thermal_cpufreq_notifier,
 160 };
 161
 162 void acpi_thermal_cpufreq_init(void)
 163 {
 164         int i;
 165
 166         for (i = 0; i < NR_CPUS; i++)
 167                 cpufreq_thermal_reduction_pctg[i] = 0;
 168
 169         i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
 170                                       CPUFREQ_POLICY_NOTIFIER);
 171         if (!i)
 172                 acpi_thermal_cpufreq_is_init = 1;
 173 }
 174
 175 void acpi_thermal_cpufreq_exit(void)
 176 {
 177         if (acpi_thermal_cpufreq_is_init)
 178                 cpufreq_unregister_notifier
 179                     (&acpi_thermal_cpufreq_notifier_block,
 180                      CPUFREQ_POLICY_NOTIFIER);
 181
 182         acpi_thermal_cpufreq_is_init = 0;
 183 }
 184
 185 #else                           /* ! CONFIG_CPU_FREQ */
 186
 187 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
 188 {
 189         return -ENODEV;
 190 }
 191 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
 192 {
 193         return -ENODEV;
 194 }
 195
 196 #endif
 197
 198 int acpi_processor_set_thermal_limit(acpi_handle handle, int type)
 199 {
 200         int result = 0;
 201         struct acpi_processor *pr = NULL;
 202         struct acpi_device *device = NULL;
 203         int tx = 0;
 204
 205         ACPI_FUNCTION_TRACE("acpi_processor_set_thermal_limit");
 206
 207         if ((type < ACPI_PROCESSOR_LIMIT_NONE)
 208             || (type > ACPI_PROCESSOR_LIMIT_DECREMENT))
 209                 return_VALUE(-EINVAL);
 210
 211         result = acpi_bus_get_device(handle, &device);
 212         if (result)
 213                 return_VALUE(result);
 214
 215         pr = (struct acpi_processor *)acpi_driver_data(device);
 216         if (!pr)
 217                 return_VALUE(-ENODEV);
 218
 219         /* Thermal limits are always relative to the current Px/Tx state. */
 220         if (pr->flags.throttling)
 221                 pr->limit.thermal.tx = pr->throttling.state;
 222
 223         /*
 224          * Our default policy is to only use throttling at the lowest
 225          * performance state.
 226          */
 227
 228         tx = pr->limit.thermal.tx;
 229
 230         switch (type) {
 231
 232         case ACPI_PROCESSOR_LIMIT_NONE:
 233                 do {
 234                         result = acpi_thermal_cpufreq_decrease(pr->id);
 235                 } while (!result);
 236                 tx = 0;
 237                 break;
 238
 239         case ACPI_PROCESSOR_LIMIT_INCREMENT:
 240                 /* if going up: P-states first, T-states later */
 241
 242                 result = acpi_thermal_cpufreq_increase(pr->id);
 243                 if (!result)
 244                         goto end;
 245                 else if (result == -ERANGE)
 246                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 247                                           "At maximum performance state\n"));
 248
 249                 if (pr->flags.throttling) {
 250                         if (tx == (pr->throttling.state_count - 1))
 251                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 252                                                   "At maximum throttling state\n"));
 253                         else
 254                                 tx++;
 255                 }
 256                 break;
 257
 258         case ACPI_PROCESSOR_LIMIT_DECREMENT:
 259                 /* if going down: T-states first, P-states later */
 260
 261                 if (pr->flags.throttling) {
 262                         if (tx == 0)
 263                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 264                                                   "At minimum throttling state\n"));
 265                         else {
 266                                 tx--;
 267                                 goto end;
 268                         }
 269                 }
 270
 271                 result = acpi_thermal_cpufreq_decrease(pr->id);
 272                 if (result == -ERANGE)
 273                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 274                                           "At minimum performance state\n"));
 275
 276                 break;
 277         }
 278
 279       end:
 280         if (pr->flags.throttling) {
 281                 pr->limit.thermal.px = 0;
 282                 pr->limit.thermal.tx = tx;
 283
 284                 result = acpi_processor_apply_limit(pr);
 285                 if (result)
 286                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 287                                           "Unable to set thermal limit\n"));
 288
 289                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Thermal limit now (P%d:T%d)\n",
 290                                   pr->limit.thermal.px, pr->limit.thermal.tx));
 291         } else
 292                 result = 0;
 293
 294         return_VALUE(result);
 295 }
 296
 297 int acpi_processor_get_limit_info(struct acpi_processor *pr)
 298 {
 299         ACPI_FUNCTION_TRACE("acpi_processor_get_limit_info");
 300
 301         if (!pr)
 302                 return_VALUE(-EINVAL);
 303
 304         if (pr->flags.throttling)
 305                 pr->flags.limit = 1;
 306
 307         return_VALUE(0);
 308 }
 309
 310 /* /proc interface */
 311
 312 static int acpi_processor_limit_seq_show(struct seq_file *seq, void *offset)
 313 {
 314         struct acpi_processor *pr = (struct acpi_processor *)seq->private;
 315
 316         ACPI_FUNCTION_TRACE("acpi_processor_limit_seq_show");
 317
 318         if (!pr)
 319                 goto end;
 320
 321         if (!pr->flags.limit) {
 322                 seq_puts(seq, "<not supported>\n");
 323                 goto end;
 324         }
 325
 326         seq_printf(seq, "active limit:            P%d:T%d\n"
 327                    "user limit:              P%d:T%d\n"
 328                    "thermal limit:           P%d:T%d\n",
 329                    pr->limit.state.px, pr->limit.state.tx,
 330                    pr->limit.user.px, pr->limit.user.tx,
 331                    pr->limit.thermal.px, pr->limit.thermal.tx);
 332
 333       end:
 334         return_VALUE(0);
 335 }
 336
 337 static int acpi_processor_limit_open_fs(struct inode *inode, struct file *file)
 338 {
 339         return single_open(file, acpi_processor_limit_seq_show,
 340                            PDE(inode)->data);
 341 }
 342
 343 ssize_t acpi_processor_write_limit(struct file * file,
 344                                    const char __user * buffer,
 345                                    size_t count, loff_t * data)
 346 {
 347         int result = 0;
 348         struct seq_file *m = (struct seq_file *)file->private_data;
 349         struct acpi_processor *pr = (struct acpi_processor *)m->private;
 350         char limit_string[25] = { '\0' };
 351         int px = 0;
 352         int tx = 0;
 353
 354         ACPI_FUNCTION_TRACE("acpi_processor_write_limit");
 355
 356         if (!pr || (count > sizeof(limit_string) - 1)) {
 357                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid argument\n"));
 358                 return_VALUE(-EINVAL);
 359         }
 360
 361         if (copy_from_user(limit_string, buffer, count)) {
 362                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid data\n"));
 363                 return_VALUE(-EFAULT);
 364         }
 365
 366         limit_string[count] = '\0';
 367
 368         if (sscanf(limit_string, "%d:%d", &px, &tx) != 2) {
 369                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid data format\n"));
 370                 return_VALUE(-EINVAL);
 371         }
 372
 373         if (pr->flags.throttling) {
 374                 if ((tx < 0) || (tx > (pr->throttling.state_count - 1))) {
 375                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid tx\n"));
 376                         return_VALUE(-EINVAL);
 377                 }
 378                 pr->limit.user.tx = tx;
 379         }
 380
 381         result = acpi_processor_apply_limit(pr);
 382
 383         return_VALUE(count);
 384 }
 385
 386 struct file_operations acpi_processor_limit_fops = {
 387         .open = acpi_processor_limit_open_fs,
 388         .read = seq_read,
 389         .llseek = seq_lseek,
 390         .release = single_release,
 391 };