1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * processor_thermal.c - Passive cooling submodule of the ACPI processor driver
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
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>
20 #define PREFIX "ACPI: "
22 #define ACPI_PROCESSOR_CLASS "processor"
24 #ifdef CONFIG_CPU_FREQ
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.
32 #define CPUFREQ_THERMAL_MIN_STEP 0
33 #define CPUFREQ_THERMAL_MAX_STEP 3
35 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg
);
37 #define reduction_pctg(cpu) \
38 per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu))
41 * Emulate "per package data" using per cpu data (which should really be
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)
47 static int phys_package_first_cpu(int cpu
)
50 int id
= topology_physical_package_id(cpu
);
52 for_each_online_cpu(i
)
53 if (topology_physical_package_id(i
) == id
)
58 static int cpu_has_cpufreq(unsigned int cpu
)
60 struct cpufreq_policy policy
;
61 if (!acpi_processor_cpufreq_init
|| cpufreq_get_policy(&policy
, cpu
))
66 static int cpufreq_get_max_state(unsigned int cpu
)
68 if (!cpu_has_cpufreq(cpu
))
71 return CPUFREQ_THERMAL_MAX_STEP
;
74 static int cpufreq_get_cur_state(unsigned int cpu
)
76 if (!cpu_has_cpufreq(cpu
))
79 return reduction_pctg(cpu
);
82 static int cpufreq_set_cur_state(unsigned int cpu
, int state
)
84 struct cpufreq_policy
*policy
;
85 struct acpi_processor
*pr
;
86 unsigned long max_freq
;
89 if (!cpu_has_cpufreq(cpu
))
92 reduction_pctg(cpu
) = state
;
95 * Update all the CPUs in the same package because they all
96 * contribute to the temperature and often share the same
99 for_each_online_cpu(i
) {
100 if (topology_physical_package_id(i
) !=
101 topology_physical_package_id(cpu
))
104 pr
= per_cpu(processors
, i
);
106 if (unlikely(!freq_qos_request_active(&pr
->thermal_req
)))
109 policy
= cpufreq_cpu_get(i
);
113 max_freq
= (policy
->cpuinfo
.max_freq
* (100 - reduction_pctg(i
) * 20)) / 100;
115 cpufreq_cpu_put(policy
);
117 ret
= freq_qos_update_request(&pr
->thermal_req
, max_freq
);
119 pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
126 void acpi_thermal_cpufreq_init(struct cpufreq_policy
*policy
)
130 for_each_cpu(cpu
, policy
->related_cpus
) {
131 struct acpi_processor
*pr
= per_cpu(processors
, cpu
);
137 ret
= freq_qos_add_request(&policy
->constraints
,
139 FREQ_QOS_MAX
, INT_MAX
);
141 pr_err("Failed to add freq constraint for CPU%d (%d)\n",
146 void acpi_thermal_cpufreq_exit(struct cpufreq_policy
*policy
)
150 for_each_cpu(cpu
, policy
->related_cpus
) {
151 struct acpi_processor
*pr
= per_cpu(processors
, policy
->cpu
);
154 freq_qos_remove_request(&pr
->thermal_req
);
157 #else /* ! CONFIG_CPU_FREQ */
158 static int cpufreq_get_max_state(unsigned int cpu
)
163 static int cpufreq_get_cur_state(unsigned int cpu
)
168 static int cpufreq_set_cur_state(unsigned int cpu
, int state
)
175 /* thermal cooling device callbacks */
176 static int acpi_processor_max_state(struct acpi_processor
*pr
)
181 * There exists four states according to
182 * cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
184 max_state
+= cpufreq_get_max_state(pr
->id
);
185 if (pr
->flags
.throttling
)
186 max_state
+= (pr
->throttling
.state_count
-1);
191 processor_get_max_state(struct thermal_cooling_device
*cdev
,
192 unsigned long *state
)
194 struct acpi_device
*device
= cdev
->devdata
;
195 struct acpi_processor
*pr
;
200 pr
= acpi_driver_data(device
);
204 *state
= acpi_processor_max_state(pr
);
209 processor_get_cur_state(struct thermal_cooling_device
*cdev
,
210 unsigned long *cur_state
)
212 struct acpi_device
*device
= cdev
->devdata
;
213 struct acpi_processor
*pr
;
218 pr
= acpi_driver_data(device
);
222 *cur_state
= cpufreq_get_cur_state(pr
->id
);
223 if (pr
->flags
.throttling
)
224 *cur_state
+= pr
->throttling
.state
;
229 processor_set_cur_state(struct thermal_cooling_device
*cdev
,
232 struct acpi_device
*device
= cdev
->devdata
;
233 struct acpi_processor
*pr
;
240 pr
= acpi_driver_data(device
);
244 max_pstate
= cpufreq_get_max_state(pr
->id
);
246 if (state
> acpi_processor_max_state(pr
))
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
);
254 cpufreq_set_cur_state(pr
->id
, max_pstate
);
255 result
= acpi_processor_set_throttling(pr
,
256 state
- max_pstate
, false);
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
,