Pileus Git - ~andy/linux/blob - 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/sysdev.h>
  34
  35 #include <asm/uaccess.h>
  36
  37 #include <acpi/acpi_bus.h>
  38 #include <acpi/processor.h>
  39 #include <acpi/acpi_drivers.h>
  40
  41 #define PREFIX "ACPI: "
  42
  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, false);
  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 #define CPUFREQ_THERMAL_MIN_STEP 0
  97 #define CPUFREQ_THERMAL_MAX_STEP 3
  98
  99 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
 100 static unsigned int acpi_thermal_cpufreq_is_init = 0;
 101
 102 static int cpu_has_cpufreq(unsigned int cpu)
 103 {
 104         struct cpufreq_policy policy;
 105         if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu))
 106                 return 0;
 107         return 1;
 108 }
 109
 110 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
 111 {
 112         if (!cpu_has_cpufreq(cpu))
 113                 return -ENODEV;
 114
 115         if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) <
 116                 CPUFREQ_THERMAL_MAX_STEP) {
 117                 per_cpu(cpufreq_thermal_reduction_pctg, cpu)++;
 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 (per_cpu(cpufreq_thermal_reduction_pctg, cpu) >
 131                 (CPUFREQ_THERMAL_MIN_STEP + 1))
 132                 per_cpu(cpufreq_thermal_reduction_pctg, cpu)--;
 133         else
 134                 per_cpu(cpufreq_thermal_reduction_pctg, cpu) = 0;
 135         cpufreq_update_policy(cpu);
 136         /* We reached max freq again and can leave passive mode */
 137         return !per_cpu(cpufreq_thermal_reduction_pctg, cpu);
 138 }
 139
 140 static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
 141                                          unsigned long event, void *data)
 142 {
 143         struct cpufreq_policy *policy = data;
 144         unsigned long max_freq = 0;
 145
 146         if (event != CPUFREQ_ADJUST)
 147                 goto out;
 148
 149         max_freq = (
 150             policy->cpuinfo.max_freq *
 151             (100 - per_cpu(cpufreq_thermal_reduction_pctg, policy->cpu) * 20)
 152         ) / 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 per_cpu(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         per_cpu(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_cpu_ids; i++)
 195                 if (cpu_present(i))
 196                         per_cpu(cpufreq_thermal_reduction_pctg, i) = 0;
 197
 198         i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
 199                                       CPUFREQ_POLICY_NOTIFIER);
 200         if (!i)
 201                 acpi_thermal_cpufreq_is_init = 1;
 202 }
 203
 204 void acpi_thermal_cpufreq_exit(void)
 205 {
 206         if (acpi_thermal_cpufreq_is_init)
 207                 cpufreq_unregister_notifier
 208                     (&acpi_thermal_cpufreq_notifier_block,
 209                      CPUFREQ_POLICY_NOTIFIER);
 210
 211         acpi_thermal_cpufreq_is_init = 0;
 212 }
 213
 214 #else                           /* ! CONFIG_CPU_FREQ */
 215 static int cpufreq_get_max_state(unsigned int cpu)
 216 {
 217         return 0;
 218 }
 219
 220 static int cpufreq_get_cur_state(unsigned int cpu)
 221 {
 222         return 0;
 223 }
 224
 225 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 226 {
 227         return 0;
 228 }
 229
 230 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
 231 {
 232         return -ENODEV;
 233 }
 234 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
 235 {
 236         return -ENODEV;
 237 }
 238
 239 #endif
 240
 241 int acpi_processor_get_limit_info(struct acpi_processor *pr)
 242 {
 243
 244         if (!pr)
 245                 return -EINVAL;
 246
 247         if (pr->flags.throttling)
 248                 pr->flags.limit = 1;
 249
 250         return 0;
 251 }
 252
 253 /* thermal coolign device callbacks */
 254 static int acpi_processor_max_state(struct acpi_processor *pr)
 255 {
 256         int max_state = 0;
 257
 258         /*
 259          * There exists four states according to
 260          * cpufreq_thermal_reduction_ptg. 0, 1, 2, 3
 261          */
 262         max_state += cpufreq_get_max_state(pr->id);
 263         if (pr->flags.throttling)
 264                 max_state += (pr->throttling.state_count -1);
 265
 266         return max_state;
 267 }
 268 static int
 269 processor_get_max_state(struct thermal_cooling_device *cdev,
 270                         unsigned long *state)
 271 {
 272         struct acpi_device *device = cdev->devdata;
 273         struct acpi_processor *pr = acpi_driver_data(device);
 274
 275         if (!device || !pr)
 276                 return -EINVAL;
 277
 278         *state = acpi_processor_max_state(pr);
 279         return 0;
 280 }
 281
 282 static int
 283 processor_get_cur_state(struct thermal_cooling_device *cdev,
 284                         unsigned long *cur_state)
 285 {
 286         struct acpi_device *device = cdev->devdata;
 287         struct acpi_processor *pr = acpi_driver_data(device);
 288
 289         if (!device || !pr)
 290                 return -EINVAL;
 291
 292         *cur_state = cpufreq_get_cur_state(pr->id);
 293         if (pr->flags.throttling)
 294                 *cur_state += pr->throttling.state;
 295         return 0;
 296 }
 297
 298 static int
 299 processor_set_cur_state(struct thermal_cooling_device *cdev,
 300                         unsigned long state)
 301 {
 302         struct acpi_device *device = cdev->devdata;
 303         struct acpi_processor *pr = acpi_driver_data(device);
 304         int result = 0;
 305         int max_pstate;
 306
 307         if (!device || !pr)
 308                 return -EINVAL;
 309
 310         max_pstate = cpufreq_get_max_state(pr->id);
 311
 312         if (state > acpi_processor_max_state(pr))
 313                 return -EINVAL;
 314
 315         if (state <= max_pstate) {
 316                 if (pr->flags.throttling && pr->throttling.state)
 317                         result = acpi_processor_set_throttling(pr, 0, false);
 318                 cpufreq_set_cur_state(pr->id, state);
 319         } else {
 320                 cpufreq_set_cur_state(pr->id, max_pstate);
 321                 result = acpi_processor_set_throttling(pr,
 322                                 state - max_pstate, false);
 323         }
 324         return result;
 325 }
 326
 327 struct thermal_cooling_device_ops processor_cooling_ops = {
 328         .get_max_state = processor_get_max_state,
 329         .get_cur_state = processor_get_cur_state,
 330         .set_cur_state = processor_set_cur_state,
 331 };