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 #define PREFIX "ACPI: "
  21
  22 #define ACPI_PROCESSOR_CLASS            "processor"
  23 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  24 ACPI_MODULE_NAME("processor_thermal");
  25
  26 #ifdef CONFIG_CPU_FREQ
  27
  28 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it
  29  * offers (in most cases) voltage scaling in addition to frequency scaling, and
  30  * thus a cubic (instead of linear) reduction of energy. Also, we allow for
  31  * _any_ cpufreq driver and not only the acpi-cpufreq driver.
  32  */
  33
  34 #define CPUFREQ_THERMAL_MIN_STEP 0
  35 #define CPUFREQ_THERMAL_MAX_STEP 3
  36
  37 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
  38
  39 #define reduction_pctg(cpu) \
  40         per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu))
  41
  42 /*
  43  * Emulate "per package data" using per cpu data (which should really be
  44  * provided elsewhere)
  45  *
  46  * Note we can lose a CPU on cpu hotunplug, in this case we forget the state
  47  * temporarily. Fortunately that's not a big issue here (I hope)
  48  */
  49 static int phys_package_first_cpu(int cpu)
  50 {
  51         int i;
  52         int id = topology_physical_package_id(cpu);
  53
  54         for_each_online_cpu(i)
  55                 if (topology_physical_package_id(i) == id)
  56                         return i;
  57         return 0;
  58 }
  59
  60 static int cpu_has_cpufreq(unsigned int cpu)
  61 {
  62         struct cpufreq_policy policy;
  63         if (!acpi_processor_cpufreq_init || cpufreq_get_policy(&policy, cpu))
  64                 return 0;
  65         return 1;
  66 }
  67
  68 static int cpufreq_get_max_state(unsigned int cpu)
  69 {
  70         if (!cpu_has_cpufreq(cpu))
  71                 return 0;
  72
  73         return CPUFREQ_THERMAL_MAX_STEP;
  74 }
  75
  76 static int cpufreq_get_cur_state(unsigned int cpu)
  77 {
  78         if (!cpu_has_cpufreq(cpu))
  79                 return 0;
  80
  81         return reduction_pctg(cpu);
  82 }
  83
  84 static int cpufreq_set_cur_state(unsigned int cpu, int state)
  85 {
  86         struct cpufreq_policy *policy;
  87         struct acpi_processor *pr;
  88         unsigned long max_freq;
  89         int i, ret;
  90
  91         if (!cpu_has_cpufreq(cpu))
  92                 return 0;
  93
  94         reduction_pctg(cpu) = state;
  95
  96         /*
  97          * Update all the CPUs in the same package because they all
  98          * contribute to the temperature and often share the same
  99          * frequency.
 100          */
 101         for_each_online_cpu(i) {
 102                 if (topology_physical_package_id(i) !=
 103                     topology_physical_package_id(cpu))
 104                         continue;
 105
 106                 pr = per_cpu(processors, i);
 107
 108                 if (unlikely(!freq_qos_request_active(&pr->thermal_req)))
 109                         continue;
 110
 111                 policy = cpufreq_cpu_get(i);
 112                 if (!policy)
 113                         return -EINVAL;
 114
 115                 max_freq = (policy->cpuinfo.max_freq * (100 - reduction_pctg(i) * 20)) / 100;
 116
 117                 cpufreq_cpu_put(policy);
 118
 119                 ret = freq_qos_update_request(&pr->thermal_req, max_freq);
 120                 if (ret < 0) {
 121                         pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
 122                                 pr->id, ret);
 123                 }
 124         }
 125         return 0;
 126 }
 127
 128 void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)
 129 {
 130         int cpu = policy->cpu;
 131         struct acpi_processor *pr = per_cpu(processors, cpu);
 132         int ret;
 133
 134         if (!pr)
 135                 return;
 136
 137         ret = freq_qos_add_request(&policy->constraints, &pr->thermal_req,
 138                                    FREQ_QOS_MAX, INT_MAX);
 139         if (ret < 0)
 140                 pr_err("Failed to add freq constraint for CPU%d (%d)\n", cpu,
 141                        ret);
 142 }
 143
 144 void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
 145 {
 146         struct acpi_processor *pr = per_cpu(processors, policy->cpu);
 147
 148         if (pr)
 149                 freq_qos_remove_request(&pr->thermal_req);
 150 }
 151 #else                           /* ! CONFIG_CPU_FREQ */
 152 static int cpufreq_get_max_state(unsigned int cpu)
 153 {
 154         return 0;
 155 }
 156
 157 static int cpufreq_get_cur_state(unsigned int cpu)
 158 {
 159         return 0;
 160 }
 161
 162 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 163 {
 164         return 0;
 165 }
 166
 167 #endif
 168
 169 /* thermal cooling device callbacks */
 170 static int acpi_processor_max_state(struct acpi_processor *pr)
 171 {
 172         int max_state = 0;
 173
 174         /*
 175          * There exists four states according to
 176          * cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
 177          */
 178         max_state += cpufreq_get_max_state(pr->id);
 179         if (pr->flags.throttling)
 180                 max_state += (pr->throttling.state_count -1);
 181
 182         return max_state;
 183 }
 184 static int
 185 processor_get_max_state(struct thermal_cooling_device *cdev,
 186                         unsigned long *state)
 187 {
 188         struct acpi_device *device = cdev->devdata;
 189         struct acpi_processor *pr;
 190
 191         if (!device)
 192                 return -EINVAL;
 193
 194         pr = acpi_driver_data(device);
 195         if (!pr)
 196                 return -EINVAL;
 197
 198         *state = acpi_processor_max_state(pr);
 199         return 0;
 200 }
 201
 202 static int
 203 processor_get_cur_state(struct thermal_cooling_device *cdev,
 204                         unsigned long *cur_state)
 205 {
 206         struct acpi_device *device = cdev->devdata;
 207         struct acpi_processor *pr;
 208
 209         if (!device)
 210                 return -EINVAL;
 211
 212         pr = acpi_driver_data(device);
 213         if (!pr)
 214                 return -EINVAL;
 215
 216         *cur_state = cpufreq_get_cur_state(pr->id);
 217         if (pr->flags.throttling)
 218                 *cur_state += pr->throttling.state;
 219         return 0;
 220 }
 221
 222 static int
 223 processor_set_cur_state(struct thermal_cooling_device *cdev,
 224                         unsigned long state)
 225 {
 226         struct acpi_device *device = cdev->devdata;
 227         struct acpi_processor *pr;
 228         int result = 0;
 229         int max_pstate;
 230
 231         if (!device)
 232                 return -EINVAL;
 233
 234         pr = acpi_driver_data(device);
 235         if (!pr)
 236                 return -EINVAL;
 237
 238         max_pstate = cpufreq_get_max_state(pr->id);
 239
 240         if (state > acpi_processor_max_state(pr))
 241                 return -EINVAL;
 242
 243         if (state <= max_pstate) {
 244                 if (pr->flags.throttling && pr->throttling.state)
 245                         result = acpi_processor_set_throttling(pr, 0, false);
 246                 cpufreq_set_cur_state(pr->id, state);
 247         } else {
 248                 cpufreq_set_cur_state(pr->id, max_pstate);
 249                 result = acpi_processor_set_throttling(pr,
 250                                 state - max_pstate, false);
 251         }
 252         return result;
 253 }
 254
 255 const struct thermal_cooling_device_ops processor_cooling_ops = {
 256         .get_max_state = processor_get_max_state,
 257         .get_cur_state = processor_get_cur_state,
 258         .set_cur_state = processor_set_cur_state,
 259 };