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(!dev_pm_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 = dev_pm_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(int cpu)
 129 {
 130         struct acpi_processor *pr = per_cpu(processors, cpu);
 131         int ret;
 132
 133         ret = dev_pm_qos_add_request(get_cpu_device(cpu),
 134                                      &pr->thermal_req, DEV_PM_QOS_MAX_FREQUENCY,
 135                                      INT_MAX);
 136         if (ret < 0) {
 137                 pr_err("Failed to add freq constraint for CPU%d (%d)\n", cpu,
 138                        ret);
 139                 return;
 140         }
 141 }
 142
 143 void acpi_thermal_cpufreq_exit(int cpu)
 144 {
 145         struct acpi_processor *pr = per_cpu(processors, cpu);
 146
 147         dev_pm_qos_remove_request(&pr->thermal_req);
 148 }
 149 #else                           /* ! CONFIG_CPU_FREQ */
 150 static int cpufreq_get_max_state(unsigned int cpu)
 151 {
 152         return 0;
 153 }
 154
 155 static int cpufreq_get_cur_state(unsigned int cpu)
 156 {
 157         return 0;
 158 }
 159
 160 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 161 {
 162         return 0;
 163 }
 164
 165 #endif
 166
 167 /* thermal cooling device callbacks */
 168 static int acpi_processor_max_state(struct acpi_processor *pr)
 169 {
 170         int max_state = 0;
 171
 172         /*
 173          * There exists four states according to
 174          * cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
 175          */
 176         max_state += cpufreq_get_max_state(pr->id);
 177         if (pr->flags.throttling)
 178                 max_state += (pr->throttling.state_count -1);
 179
 180         return max_state;
 181 }
 182 static int
 183 processor_get_max_state(struct thermal_cooling_device *cdev,
 184                         unsigned long *state)
 185 {
 186         struct acpi_device *device = cdev->devdata;
 187         struct acpi_processor *pr;
 188
 189         if (!device)
 190                 return -EINVAL;
 191
 192         pr = acpi_driver_data(device);
 193         if (!pr)
 194                 return -EINVAL;
 195
 196         *state = acpi_processor_max_state(pr);
 197         return 0;
 198 }
 199
 200 static int
 201 processor_get_cur_state(struct thermal_cooling_device *cdev,
 202                         unsigned long *cur_state)
 203 {
 204         struct acpi_device *device = cdev->devdata;
 205         struct acpi_processor *pr;
 206
 207         if (!device)
 208                 return -EINVAL;
 209
 210         pr = acpi_driver_data(device);
 211         if (!pr)
 212                 return -EINVAL;
 213
 214         *cur_state = cpufreq_get_cur_state(pr->id);
 215         if (pr->flags.throttling)
 216                 *cur_state += pr->throttling.state;
 217         return 0;
 218 }
 219
 220 static int
 221 processor_set_cur_state(struct thermal_cooling_device *cdev,
 222                         unsigned long state)
 223 {
 224         struct acpi_device *device = cdev->devdata;
 225         struct acpi_processor *pr;
 226         int result = 0;
 227         int max_pstate;
 228
 229         if (!device)
 230                 return -EINVAL;
 231
 232         pr = acpi_driver_data(device);
 233         if (!pr)
 234                 return -EINVAL;
 235
 236         max_pstate = cpufreq_get_max_state(pr->id);
 237
 238         if (state > acpi_processor_max_state(pr))
 239                 return -EINVAL;
 240
 241         if (state <= max_pstate) {
 242                 if (pr->flags.throttling && pr->throttling.state)
 243                         result = acpi_processor_set_throttling(pr, 0, false);
 244                 cpufreq_set_cur_state(pr->id, state);
 245         } else {
 246                 cpufreq_set_cur_state(pr->id, max_pstate);
 247                 result = acpi_processor_set_throttling(pr,
 248                                 state - max_pstate, false);
 249         }
 250         return result;
 251 }
 252
 253 const struct thermal_cooling_device_ops processor_cooling_ops = {
 254         .get_max_state = processor_get_max_state,
 255         .get_cur_state = processor_get_cur_state,
 256         .set_cur_state = processor_set_cur_state,
 257 };