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