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 */
phys_package_first_cpu(int cpu)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
cpu_has_cpufreq(unsigned int cpu)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
cpufreq_get_max_state(unsigned int cpu)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
cpufreq_get_cur_state(unsigned int cpu)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
cpufreq_set_cur_state(unsigned int cpu,int state)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
acpi_thermal_cpufreq_init(struct cpufreq_policy * policy)128 void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)
129 {
130 unsigned int cpu;
131
132 for_each_cpu(cpu, policy->related_cpus) {
133 struct acpi_processor *pr = per_cpu(processors, cpu);
134 int ret;
135
136 if (!pr)
137 continue;
138
139 ret = freq_qos_add_request(&policy->constraints,
140 &pr->thermal_req,
141 FREQ_QOS_MAX, INT_MAX);
142 if (ret < 0)
143 pr_err("Failed to add freq constraint for CPU%d (%d)\n",
144 cpu, ret);
145 }
146 }
147
acpi_thermal_cpufreq_exit(struct cpufreq_policy * policy)148 void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
149 {
150 unsigned int cpu;
151
152 for_each_cpu(cpu, policy->related_cpus) {
153 struct acpi_processor *pr = per_cpu(processors, policy->cpu);
154
155 if (pr)
156 freq_qos_remove_request(&pr->thermal_req);
157 }
158 }
159 #else /* ! CONFIG_CPU_FREQ */
cpufreq_get_max_state(unsigned int cpu)160 static int cpufreq_get_max_state(unsigned int cpu)
161 {
162 return 0;
163 }
164
cpufreq_get_cur_state(unsigned int cpu)165 static int cpufreq_get_cur_state(unsigned int cpu)
166 {
167 return 0;
168 }
169
cpufreq_set_cur_state(unsigned int cpu,int state)170 static int cpufreq_set_cur_state(unsigned int cpu, int state)
171 {
172 return 0;
173 }
174
175 #endif
176
177 /* thermal cooling device callbacks */
acpi_processor_max_state(struct acpi_processor * pr)178 static int acpi_processor_max_state(struct acpi_processor *pr)
179 {
180 int max_state = 0;
181
182 /*
183 * There exists four states according to
184 * cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
185 */
186 max_state += cpufreq_get_max_state(pr->id);
187 if (pr->flags.throttling)
188 max_state += (pr->throttling.state_count -1);
189
190 return max_state;
191 }
192 static int
processor_get_max_state(struct thermal_cooling_device * cdev,unsigned long * state)193 processor_get_max_state(struct thermal_cooling_device *cdev,
194 unsigned long *state)
195 {
196 struct acpi_device *device = cdev->devdata;
197 struct acpi_processor *pr;
198
199 if (!device)
200 return -EINVAL;
201
202 pr = acpi_driver_data(device);
203 if (!pr)
204 return -EINVAL;
205
206 *state = acpi_processor_max_state(pr);
207 return 0;
208 }
209
210 static int
processor_get_cur_state(struct thermal_cooling_device * cdev,unsigned long * cur_state)211 processor_get_cur_state(struct thermal_cooling_device *cdev,
212 unsigned long *cur_state)
213 {
214 struct acpi_device *device = cdev->devdata;
215 struct acpi_processor *pr;
216
217 if (!device)
218 return -EINVAL;
219
220 pr = acpi_driver_data(device);
221 if (!pr)
222 return -EINVAL;
223
224 *cur_state = cpufreq_get_cur_state(pr->id);
225 if (pr->flags.throttling)
226 *cur_state += pr->throttling.state;
227 return 0;
228 }
229
230 static int
processor_set_cur_state(struct thermal_cooling_device * cdev,unsigned long state)231 processor_set_cur_state(struct thermal_cooling_device *cdev,
232 unsigned long state)
233 {
234 struct acpi_device *device = cdev->devdata;
235 struct acpi_processor *pr;
236 int result = 0;
237 int max_pstate;
238
239 if (!device)
240 return -EINVAL;
241
242 pr = acpi_driver_data(device);
243 if (!pr)
244 return -EINVAL;
245
246 max_pstate = cpufreq_get_max_state(pr->id);
247
248 if (state > acpi_processor_max_state(pr))
249 return -EINVAL;
250
251 if (state <= max_pstate) {
252 if (pr->flags.throttling && pr->throttling.state)
253 result = acpi_processor_set_throttling(pr, 0, false);
254 cpufreq_set_cur_state(pr->id, state);
255 } else {
256 cpufreq_set_cur_state(pr->id, max_pstate);
257 result = acpi_processor_set_throttling(pr,
258 state - max_pstate, false);
259 }
260 return result;
261 }
262
263 const struct thermal_cooling_device_ops processor_cooling_ops = {
264 .get_max_state = processor_get_max_state,
265 .get_cur_state = processor_get_cur_state,
266 .set_cur_state = processor_set_cur_state,
267 };
268