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
  24 #ifdef CONFIG_CPU_FREQ
  25
  26 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it
  27  * offers (in most cases) voltage scaling in addition to frequency scaling, and
  28  * thus a cubic (instead of linear) reduction of energy. Also, we allow for
  29  * _any_ cpufreq driver and not only the acpi-cpufreq driver.
  30  */
  31
  32 #define CPUFREQ_THERMAL_MIN_STEP 0
  33 #define CPUFREQ_THERMAL_MAX_STEP 3
  34
  35 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
  36
  37 #define reduction_pctg(cpu) \
  38         per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu))
  39
  40 /*
  41  * Emulate "per package data" using per cpu data (which should really be
  42  * provided elsewhere)
  43  *
  44  * Note we can lose a CPU on cpu hotunplug, in this case we forget the state
  45  * temporarily. Fortunately that's not a big issue here (I hope)
  46  */
  47 static int phys_package_first_cpu(int cpu)
  48 {
  49         int i;
  50         int id = topology_physical_package_id(cpu);
  51
  52         for_each_online_cpu(i)
  53                 if (topology_physical_package_id(i) == id)
  54                         return i;
  55         return 0;
  56 }
  57
  58 static int cpu_has_cpufreq(unsigned int cpu)
  59 {
  60         struct cpufreq_policy policy;
  61         if (!acpi_processor_cpufreq_init || cpufreq_get_policy(&policy, cpu))
  62                 return 0;
  63         return 1;
  64 }
  65
  66 static int cpufreq_get_max_state(unsigned int cpu)
  67 {
  68         if (!cpu_has_cpufreq(cpu))
  69                 return 0;
  70
  71         return CPUFREQ_THERMAL_MAX_STEP;
  72 }
  73
  74 static int cpufreq_get_cur_state(unsigned int cpu)
  75 {
  76         if (!cpu_has_cpufreq(cpu))
  77                 return 0;
  78
  79         return reduction_pctg(cpu);
  80 }
  81
  82 static int cpufreq_set_cur_state(unsigned int cpu, int state)
  83 {
  84         struct cpufreq_policy *policy;
  85         struct acpi_processor *pr;
  86         unsigned long max_freq;
  87         int i, ret;
  88
  89         if (!cpu_has_cpufreq(cpu))
  90                 return 0;
  91
  92         reduction_pctg(cpu) = state;
  93
  94         /*
  95          * Update all the CPUs in the same package because they all
  96          * contribute to the temperature and often share the same
  97          * frequency.
  98          */
  99         for_each_online_cpu(i) {
 100                 if (topology_physical_package_id(i) !=
 101                     topology_physical_package_id(cpu))
 102                         continue;
 103
 104                 pr = per_cpu(processors, i);
 105
 106                 if (unlikely(!freq_qos_request_active(&pr->thermal_req)))
 107                         continue;
 108
 109                 policy = cpufreq_cpu_get(i);
 110                 if (!policy)
 111                         return -EINVAL;
 112
 113                 max_freq = (policy->cpuinfo.max_freq * (100 - reduction_pctg(i) * 20)) / 100;
 114
 115                 cpufreq_cpu_put(policy);
 116
 117                 ret = freq_qos_update_request(&pr->thermal_req, max_freq);
 118                 if (ret < 0) {
 119                         pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
 120                                 pr->id, ret);
 121                 }
 122         }
 123         return 0;
 124 }
 125
 126 void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)
 127 {
 128         unsigned int cpu;
 129
 130         for_each_cpu(cpu, policy->related_cpus) {
 131                 struct acpi_processor *pr = per_cpu(processors, cpu);
 132                 int ret;
 133
 134                 if (!pr)
 135                         continue;
 136
 137                 ret = freq_qos_add_request(&policy->constraints,
 138                                            &pr->thermal_req,
 139                                            FREQ_QOS_MAX, INT_MAX);
 140                 if (ret < 0)
 141                         pr_err("Failed to add freq constraint for CPU%d (%d)\n",
 142                                cpu, ret);
 143         }
 144 }
 145
 146 void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
 147 {
 148         unsigned int cpu;
 149
 150         for_each_cpu(cpu, policy->related_cpus) {
 151                 struct acpi_processor *pr = per_cpu(processors, policy->cpu);
 152
 153                 if (pr)
 154                         freq_qos_remove_request(&pr->thermal_req);
 155         }
 156 }
 157 #else                           /* ! CONFIG_CPU_FREQ */
 158 static int cpufreq_get_max_state(unsigned int cpu)
 159 {
 160         return 0;
 161 }
 162
 163 static int cpufreq_get_cur_state(unsigned int cpu)
 164 {
 165         return 0;
 166 }
 167
 168 static int cpufreq_set_cur_state(unsigned int cpu, int state)
 169 {
 170         return 0;
 171 }
 172
 173 #endif
 174
 175 /* thermal cooling device callbacks */
 176 static int acpi_processor_max_state(struct acpi_processor *pr)
 177 {
 178         int max_state = 0;
 179
 180         /*
 181          * There exists four states according to
 182          * cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
 183          */
 184         max_state += cpufreq_get_max_state(pr->id);
 185         if (pr->flags.throttling)
 186                 max_state += (pr->throttling.state_count -1);
 187
 188         return max_state;
 189 }
 190 static int
 191 processor_get_max_state(struct thermal_cooling_device *cdev,
 192                         unsigned long *state)
 193 {
 194         struct acpi_device *device = cdev->devdata;
 195         struct acpi_processor *pr;
 196
 197         if (!device)
 198                 return -EINVAL;
 199
 200         pr = acpi_driver_data(device);
 201         if (!pr)
 202                 return -EINVAL;
 203
 204         *state = acpi_processor_max_state(pr);
 205         return 0;
 206 }
 207
 208 static int
 209 processor_get_cur_state(struct thermal_cooling_device *cdev,
 210                         unsigned long *cur_state)
 211 {
 212         struct acpi_device *device = cdev->devdata;
 213         struct acpi_processor *pr;
 214
 215         if (!device)
 216                 return -EINVAL;
 217
 218         pr = acpi_driver_data(device);
 219         if (!pr)
 220                 return -EINVAL;
 221
 222         *cur_state = cpufreq_get_cur_state(pr->id);
 223         if (pr->flags.throttling)
 224                 *cur_state += pr->throttling.state;
 225         return 0;
 226 }
 227
 228 static int
 229 processor_set_cur_state(struct thermal_cooling_device *cdev,
 230                         unsigned long state)
 231 {
 232         struct acpi_device *device = cdev->devdata;
 233         struct acpi_processor *pr;
 234         int result = 0;
 235         int max_pstate;
 236
 237         if (!device)
 238                 return -EINVAL;
 239
 240         pr = acpi_driver_data(device);
 241         if (!pr)
 242                 return -EINVAL;
 243
 244         max_pstate = cpufreq_get_max_state(pr->id);
 245
 246         if (state > acpi_processor_max_state(pr))
 247                 return -EINVAL;
 248
 249         if (state <= max_pstate) {
 250                 if (pr->flags.throttling && pr->throttling.state)
 251                         result = acpi_processor_set_throttling(pr, 0, false);
 252                 cpufreq_set_cur_state(pr->id, state);
 253         } else {
 254                 cpufreq_set_cur_state(pr->id, max_pstate);
 255                 result = acpi_processor_set_throttling(pr,
 256                                 state - max_pstate, false);
 257         }
 258         return result;
 259 }
 260
 261 const struct thermal_cooling_device_ops processor_cooling_ops = {
 262         .get_max_state = processor_get_max_state,
 263         .get_cur_state = processor_get_cur_state,
 264         .set_cur_state = processor_set_cur_state,
 265 };