drivers/acpi/processor_thermal.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * processor_thermal.c - Passive cooling submodule of the ACPI processor driver
   4  *
   5  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   7  *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
   8  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   9  *                      - Added processor hotplug support
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/cpufreq.h>
  16 #include <linux/acpi.h>
  17 #include <acpi/processor.h>
  18 #include <linux/uaccess.h>
  19
  20 #ifdef CONFIG_CPU_FREQ
  21
  22 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it
  23  * offers (in most cases) voltage scaling in addition to frequency scaling, and
  24  * thus a cubic (instead of linear) reduction of energy. Also, we allow for
  25  * _any_ cpufreq driver and not only the acpi-cpufreq driver.
  26  */
  27
  28 #define CPUFREQ_THERMAL_MIN_STEP 0
  29 #define CPUFREQ_THERMAL_MAX_STEP 3
  30
  31 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
  32
  33 #define reduction_pctg(cpu) \
  34         per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu))
  35
  36 /*
  37  * Emulate "per package data" using per cpu data (which should really be
  38  * provided elsewhere)
  39  *
  40  * Note we can lose a CPU on cpu hotunplug, in this case we forget the state
  41  * temporarily. Fortunately that's not a big issue here (I hope)
  42  */
  43 static int phys_package_first_cpu(int cpu)
  44 {
  45         int i;
  46         int id = topology_physical_package_id(cpu);
  47
  48         for_each_online_cpu(i)
  49                 if (topology_physical_package_id(i) == id)
  50                         return i;
  51         return 0;
  52 }
  53
  54 static int cpu_has_cpufreq(unsigned int cpu)
  55 {
  56         struct cpufreq_policy *policy;
  57
  58         if (!acpi_processor_cpufreq_init)
  59                 return 0;
  60
  61         policy = cpufreq_cpu_get(cpu);
  62         if (policy) {
  63                 cpufreq_cpu_put(policy);
  64                 return 1;
  65         }
  66         return 0;
  67 }
  68
  69 static int cpufreq_get_max_state(unsigned int cpu)
  70 {
  71         if (!cpu_has_cpufreq(cpu))
  72                 return 0;
  73
  74         return CPUFREQ_THERMAL_MAX_STEP;
  75 }
  76
  77 static int cpufreq_get_cur_state(unsigned int cpu)
  78 {
  79         if (!cpu_has_cpufreq(cpu))
  80                 return 0;
  81
  82         return reduction_pctg(cpu);
  83 }
  84
  85 static int cpufreq_set_cur_state(unsigned int cpu, int state)
  86 {
  87         struct cpufreq_policy *policy;
  88         struct acpi_processor *pr;
  89         unsigned long max_freq;
  90         int i, ret;
  91
  92         if (!cpu_has_cpufreq(cpu))
  93                 return 0;
  94
  95         reduction_pctg(cpu) = state;
  96
  97         /*
  98          * Update all the CPUs in the same package because they all
  99          * contribute to the temperature and often share the same
 100          * frequency.
 101          */
 102         for_each_online_cpu(i) {
 103                 if (topology_physical_package_id(i) !=
 104                     topology_physical_package_id(cpu))
 105                         continue;
 106
 107                 pr = per_cpu(processors, i);
 108
 109                 if (unlikely(!freq_qos_request_active(&pr->thermal_req)))
 110                         continue;
 111
 112                 policy = cpufreq_cpu_get(i);
 113                 if (!policy)
 114                         return -EINVAL;
 115
 116                 max_freq = (policy->cpuinfo.max_freq * (100 - reduction_pctg(i) * 20)) / 100;
 117
 118                 cpufreq_cpu_put(policy);
 119
 120                 ret = freq_qos_update_request(&pr->thermal_req, max_freq);
 121                 if (ret < 0) {
 122                         pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
 123                                 pr->id, ret);
 124                 }
 125         }
 126         return 0;
 127 }
 128
 129 void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)
 130 {
 131         unsigned int cpu;
 132
 133         for_each_cpu(cpu, policy->related_cpus) {
 134                 struct acpi_processor *pr = per_cpu(processors, cpu);
 135                 int ret;
 136
 137                 if (!pr)
 138                         continue;
 139
 140                 ret = freq_qos_add_request(&policy->constraints,
 141                                            &pr->thermal_req,
 142                                            FREQ_QOS_MAX, INT_MAX);
 143                 if (ret < 0) {
 144                         pr_err("Failed to add freq constraint for CPU%d (%d)\n",
 145                                cpu, ret);
 146                         continue;
 147                 }
 148
 149                 thermal_cooling_device_update(pr->cdev);
 150         }
 151 }
 152
 153 void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
 154 {
 155         unsigned int cpu;
 156
 157         for_each_cpu(cpu, policy->related_cpus) {
 158                 struct acpi_processor *pr = per_cpu(processors, cpu);
 159
 160                 if (!pr)
 161                         continue;
 162
 163                 freq_qos_remove_request(&pr->thermal_req);
 164
 165                 thermal_cooling_device_update(pr->cdev);
 166         }
 167 }
 168 #else                           /* ! CONFIG_CPU_FREQ */
 169 static int cpufreq_get_max_state(unsigned int cpu)
 170 {
 171         return 0;
 172 }
 173
 174 static int cpufreq_get_cur_state(unsigned int cpu)
 175 {
 176         return 0;
 177 }
 178
 179 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 180 {
 181         return 0;
 182 }
 183
 184 #endif
 185
 186 /* thermal cooling device callbacks */
 187 static int acpi_processor_max_state(struct acpi_processor *pr)
 188 {
 189         int max_state = 0;
 190
 191         /*
 192          * There exists four states according to
 193          * cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
 194          */
 195         max_state += cpufreq_get_max_state(pr->id);
 196         if (pr->flags.throttling)
 197                 max_state += (pr->throttling.state_count -1);
 198
 199         return max_state;
 200 }
 201 static int
 202 processor_get_max_state(struct thermal_cooling_device *cdev,
 203                         unsigned long *state)
 204 {
 205         struct acpi_device *device = cdev->devdata;
 206         struct acpi_processor *pr;
 207
 208         if (!device)
 209                 return -EINVAL;
 210
 211         pr = acpi_driver_data(device);
 212         if (!pr)
 213                 return -EINVAL;
 214
 215         *state = acpi_processor_max_state(pr);
 216         return 0;
 217 }
 218
 219 static int
 220 processor_get_cur_state(struct thermal_cooling_device *cdev,
 221                         unsigned long *cur_state)
 222 {
 223         struct acpi_device *device = cdev->devdata;
 224         struct acpi_processor *pr;
 225
 226         if (!device)
 227                 return -EINVAL;
 228
 229         pr = acpi_driver_data(device);
 230         if (!pr)
 231                 return -EINVAL;
 232
 233         *cur_state = cpufreq_get_cur_state(pr->id);
 234         if (pr->flags.throttling)
 235                 *cur_state += pr->throttling.state;
 236         return 0;
 237 }
 238
 239 static int
 240 processor_set_cur_state(struct thermal_cooling_device *cdev,
 241                         unsigned long state)
 242 {
 243         struct acpi_device *device = cdev->devdata;
 244         struct acpi_processor *pr;
 245         int result = 0;
 246         int max_pstate;
 247
 248         if (!device)
 249                 return -EINVAL;
 250
 251         pr = acpi_driver_data(device);
 252         if (!pr)
 253                 return -EINVAL;
 254
 255         max_pstate = cpufreq_get_max_state(pr->id);
 256
 257         if (state > acpi_processor_max_state(pr))
 258                 return -EINVAL;
 259
 260         if (state <= max_pstate) {
 261                 if (pr->flags.throttling && pr->throttling.state)
 262                         result = acpi_processor_set_throttling(pr, 0, false);
 263                 cpufreq_set_cur_state(pr->id, state);
 264         } else {
 265                 cpufreq_set_cur_state(pr->id, max_pstate);
 266                 result = acpi_processor_set_throttling(pr,
 267                                 state - max_pstate, false);
 268         }
 269         return result;
 270 }
 271
 272 const struct thermal_cooling_device_ops processor_cooling_ops = {
 273         .get_max_state = processor_get_max_state,
 274         .get_cur_state = processor_get_cur_state,
 275         .set_cur_state = processor_set_cur_state,
 276 };
 277
 278 int acpi_processor_thermal_init(struct acpi_processor *pr,
 279                                 struct acpi_device *device)
 280 {
 281         int result = 0;
 282
 283         pr->cdev = thermal_cooling_device_register("Processor", device,
 284                                                    &processor_cooling_ops);
 285         if (IS_ERR(pr->cdev)) {
 286                 result = PTR_ERR(pr->cdev);
 287                 return result;
 288         }
 289
 290         dev_dbg(&device->dev, "registered as cooling_device%d\n",
 291                 pr->cdev->id);
 292
 293         result = sysfs_create_link(&device->dev.kobj,
 294                                    &pr->cdev->device.kobj,
 295                                    "thermal_cooling");
 296         if (result) {
 297                 dev_err(&device->dev,
 298                         "Failed to create sysfs link 'thermal_cooling'\n");
 299                 goto err_thermal_unregister;
 300         }
 301
 302         result = sysfs_create_link(&pr->cdev->device.kobj,
 303                                    &device->dev.kobj,
 304                                    "device");
 305         if (result) {
 306                 dev_err(&pr->cdev->device,
 307                         "Failed to create sysfs link 'device'\n");
 308                 goto err_remove_sysfs_thermal;
 309         }
 310
 311         return 0;
 312
 313 err_remove_sysfs_thermal:
 314         sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
 315 err_thermal_unregister:
 316         thermal_cooling_device_unregister(pr->cdev);
 317
 318         return result;
 319 }
 320
 321 void acpi_processor_thermal_exit(struct acpi_processor *pr,
 322                                  struct acpi_device *device)
 323 {
 324         if (pr->cdev) {
 325                 sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
 326                 sysfs_remove_link(&pr->cdev->device.kobj, "device");
 327                 thermal_cooling_device_unregister(pr->cdev);
 328                 pr->cdev = NULL;
 329         }
 330 }