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 #ifdef CONFIG_CPU_FREQ
  23
  24 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it
  25  * offers (in most cases) voltage scaling in addition to frequency scaling, and
  26  * thus a cubic (instead of linear) reduction of energy. Also, we allow for
  27  * _any_ cpufreq driver and not only the acpi-cpufreq driver.
  28  */
  29
  30 #define CPUFREQ_THERMAL_MIN_STEP 0
  31 #define CPUFREQ_THERMAL_MAX_STEP 3
  32
  33 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
  34
  35 #define reduction_pctg(cpu) \
  36         per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu))
  37
  38 /*
  39  * Emulate "per package data" using per cpu data (which should really be
  40  * provided elsewhere)
  41  *
  42  * Note we can lose a CPU on cpu hotunplug, in this case we forget the state
  43  * temporarily. Fortunately that's not a big issue here (I hope)
  44  */
  45 static int phys_package_first_cpu(int cpu)
  46 {
  47         int i;
  48         int id = topology_physical_package_id(cpu);
  49
  50         for_each_online_cpu(i)
  51                 if (topology_physical_package_id(i) == id)
  52                         return i;
  53         return 0;
  54 }
  55
  56 static int cpu_has_cpufreq(unsigned int cpu)
  57 {
  58         struct cpufreq_policy policy;
  59         if (!acpi_processor_cpufreq_init || cpufreq_get_policy(&policy, cpu))
  60                 return 0;
  61         return 1;
  62 }
  63
  64 static int cpufreq_get_max_state(unsigned int cpu)
  65 {
  66         if (!cpu_has_cpufreq(cpu))
  67                 return 0;
  68
  69         return CPUFREQ_THERMAL_MAX_STEP;
  70 }
  71
  72 static int cpufreq_get_cur_state(unsigned int cpu)
  73 {
  74         if (!cpu_has_cpufreq(cpu))
  75                 return 0;
  76
  77         return reduction_pctg(cpu);
  78 }
  79
  80 static int cpufreq_set_cur_state(unsigned int cpu, int state)
  81 {
  82         struct cpufreq_policy *policy;
  83         struct acpi_processor *pr;
  84         unsigned long max_freq;
  85         int i, ret;
  86
  87         if (!cpu_has_cpufreq(cpu))
  88                 return 0;
  89
  90         reduction_pctg(cpu) = state;
  91
  92         /*
  93          * Update all the CPUs in the same package because they all
  94          * contribute to the temperature and often share the same
  95          * frequency.
  96          */
  97         for_each_online_cpu(i) {
  98                 if (topology_physical_package_id(i) !=
  99                     topology_physical_package_id(cpu))
 100                         continue;
 101
 102                 pr = per_cpu(processors, i);
 103
 104                 if (unlikely(!freq_qos_request_active(&pr->thermal_req)))
 105                         continue;
 106
 107                 policy = cpufreq_cpu_get(i);
 108                 if (!policy)
 109                         return -EINVAL;
 110
 111                 max_freq = (policy->cpuinfo.max_freq * (100 - reduction_pctg(i) * 20)) / 100;
 112
 113                 cpufreq_cpu_put(policy);
 114
 115                 ret = freq_qos_update_request(&pr->thermal_req, max_freq);
 116                 if (ret < 0) {
 117                         pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
 118                                 pr->id, ret);
 119                 }
 120         }
 121         return 0;
 122 }
 123
 124 void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)
 125 {
 126         unsigned int cpu;
 127
 128         for_each_cpu(cpu, policy->related_cpus) {
 129                 struct acpi_processor *pr = per_cpu(processors, cpu);
 130                 int ret;
 131
 132                 if (!pr)
 133                         continue;
 134
 135                 ret = freq_qos_add_request(&policy->constraints,
 136                                            &pr->thermal_req,
 137                                            FREQ_QOS_MAX, INT_MAX);
 138                 if (ret < 0)
 139                         pr_err("Failed to add freq constraint for CPU%d (%d)\n",
 140                                cpu, ret);
 141         }
 142 }
 143
 144 void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
 145 {
 146         unsigned int cpu;
 147
 148         for_each_cpu(cpu, policy->related_cpus) {
 149                 struct acpi_processor *pr = per_cpu(processors, policy->cpu);
 150
 151                 if (pr)
 152                         freq_qos_remove_request(&pr->thermal_req);
 153         }
 154 }
 155 #else                           /* ! CONFIG_CPU_FREQ */
 156 static int cpufreq_get_max_state(unsigned int cpu)
 157 {
 158         return 0;
 159 }
 160
 161 static int cpufreq_get_cur_state(unsigned int cpu)
 162 {
 163         return 0;
 164 }
 165
 166 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 167 {
 168         return 0;
 169 }
 170
 171 #endif
 172
 173 /* thermal cooling device callbacks */
 174 static int acpi_processor_max_state(struct acpi_processor *pr)
 175 {
 176         int max_state = 0;
 177
 178         /*
 179          * There exists four states according to
 180          * cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
 181          */
 182         max_state += cpufreq_get_max_state(pr->id);
 183         if (pr->flags.throttling)
 184                 max_state += (pr->throttling.state_count -1);
 185
 186         return max_state;
 187 }
 188 static int
 189 processor_get_max_state(struct thermal_cooling_device *cdev,
 190                         unsigned long *state)
 191 {
 192         struct acpi_device *device = cdev->devdata;
 193         struct acpi_processor *pr;
 194
 195         if (!device)
 196                 return -EINVAL;
 197
 198         pr = acpi_driver_data(device);
 199         if (!pr)
 200                 return -EINVAL;
 201
 202         *state = acpi_processor_max_state(pr);
 203         return 0;
 204 }
 205
 206 static int
 207 processor_get_cur_state(struct thermal_cooling_device *cdev,
 208                         unsigned long *cur_state)
 209 {
 210         struct acpi_device *device = cdev->devdata;
 211         struct acpi_processor *pr;
 212
 213         if (!device)
 214                 return -EINVAL;
 215
 216         pr = acpi_driver_data(device);
 217         if (!pr)
 218                 return -EINVAL;
 219
 220         *cur_state = cpufreq_get_cur_state(pr->id);
 221         if (pr->flags.throttling)
 222                 *cur_state += pr->throttling.state;
 223         return 0;
 224 }
 225
 226 static int
 227 processor_set_cur_state(struct thermal_cooling_device *cdev,
 228                         unsigned long state)
 229 {
 230         struct acpi_device *device = cdev->devdata;
 231         struct acpi_processor *pr;
 232         int result = 0;
 233         int max_pstate;
 234
 235         if (!device)
 236                 return -EINVAL;
 237
 238         pr = acpi_driver_data(device);
 239         if (!pr)
 240                 return -EINVAL;
 241
 242         max_pstate = cpufreq_get_max_state(pr->id);
 243
 244         if (state > acpi_processor_max_state(pr))
 245                 return -EINVAL;
 246
 247         if (state <= max_pstate) {
 248                 if (pr->flags.throttling && pr->throttling.state)
 249                         result = acpi_processor_set_throttling(pr, 0, false);
 250                 cpufreq_set_cur_state(pr->id, state);
 251         } else {
 252                 cpufreq_set_cur_state(pr->id, max_pstate);
 253                 result = acpi_processor_set_throttling(pr,
 254                                 state - max_pstate, false);
 255         }
 256         return result;
 257 }
 258
 259 const struct thermal_cooling_device_ops processor_cooling_ops = {
 260         .get_max_state = processor_get_max_state,
 261         .get_cur_state = processor_get_cur_state,
 262         .set_cur_state = processor_set_cur_state,
 263 };