1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * processor_driver.c - 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 * Copyright (C) 2013, Intel Corporation
11 * Rafael J. Wysocki <rafael.j.wysocki@intel.com>
12 */
13
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/init.h>
17#include <linux/cpufreq.h>
18#include <linux/cpu.h>
19#include <linux/cpuidle.h>
20#include <linux/slab.h>
21#include <linux/acpi.h>
22
23#include <acpi/processor.h>
24
25#include "internal.h"
26
27#define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
28#define ACPI_PROCESSOR_NOTIFY_POWER 0x81
29#define ACPI_PROCESSOR_NOTIFY_THROTTLING 0x82
30#define ACPI_PROCESSOR_NOTIFY_HIGEST_PERF_CHANGED 0x85
31
32MODULE_AUTHOR("Paul Diefenbaugh");
33MODULE_DESCRIPTION("ACPI Processor Driver");
34MODULE_LICENSE("GPL");
35
36static int acpi_processor_start(struct device *dev);
37static int acpi_processor_stop(struct device *dev);
38
39static const struct acpi_device_id processor_device_ids[] = {
40 {ACPI_PROCESSOR_OBJECT_HID, 0},
41 {ACPI_PROCESSOR_DEVICE_HID, 0},
42 {"", 0},
43};
44MODULE_DEVICE_TABLE(acpi, processor_device_ids);
45
46static struct device_driver acpi_processor_driver = {
47 .name = "processor",
48 .bus = &cpu_subsys,
49 .acpi_match_table = processor_device_ids,
50 .probe = acpi_processor_start,
51 .remove = acpi_processor_stop,
52};
53
54static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
55{
56 struct acpi_device *device = data;
57 struct acpi_processor *pr;
58 int saved;
59
60 if (device->handle != handle)
61 return;
62
63 pr = acpi_driver_data(d: device);
64 if (!pr)
65 return;
66
67 switch (event) {
68 case ACPI_PROCESSOR_NOTIFY_PERFORMANCE:
69 saved = pr->performance_platform_limit;
70 acpi_processor_ppc_has_changed(pr, event_flag: 1);
71 if (saved == pr->performance_platform_limit)
72 break;
73 acpi_bus_generate_netlink_event(device->pnp.device_class,
74 dev_name(dev: &device->dev), event,
75 pr->performance_platform_limit);
76 break;
77 case ACPI_PROCESSOR_NOTIFY_POWER:
78 acpi_processor_power_state_has_changed(pr);
79 acpi_bus_generate_netlink_event(device->pnp.device_class,
80 dev_name(dev: &device->dev), event, 0);
81 break;
82 case ACPI_PROCESSOR_NOTIFY_THROTTLING:
83 acpi_processor_tstate_has_changed(pr);
84 acpi_bus_generate_netlink_event(device->pnp.device_class,
85 dev_name(dev: &device->dev), event, 0);
86 break;
87 case ACPI_PROCESSOR_NOTIFY_HIGEST_PERF_CHANGED:
88 cpufreq_update_limits(cpu: pr->id);
89 acpi_bus_generate_netlink_event(device->pnp.device_class,
90 dev_name(dev: &device->dev), event, 0);
91 break;
92 default:
93 acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
94 break;
95 }
96
97 return;
98}
99
100static int __acpi_processor_start(struct acpi_device *device);
101
102static int acpi_soft_cpu_online(unsigned int cpu)
103{
104 struct acpi_processor *pr = per_cpu(processors, cpu);
105 struct acpi_device *device;
106
107 if (!pr)
108 return 0;
109
110 device = acpi_fetch_acpi_dev(handle: pr->handle);
111 if (!device)
112 return 0;
113
114 /*
115 * CPU got physically hotplugged and onlined for the first time:
116 * Initialize missing things.
117 */
118 if (pr->flags.need_hotplug_init) {
119 int ret;
120
121 pr_info("Will online and init hotplugged CPU: %d\n",
122 pr->id);
123 pr->flags.need_hotplug_init = 0;
124 ret = __acpi_processor_start(device);
125 WARN(ret, "Failed to start CPU: %d\n", pr->id);
126 } else {
127 /* Normal CPU soft online event. */
128 acpi_processor_ppc_has_changed(pr, event_flag: 0);
129 acpi_processor_hotplug(pr);
130 acpi_processor_reevaluate_tstate(pr, is_dead: false);
131 acpi_processor_tstate_has_changed(pr);
132 }
133 return 0;
134}
135
136static int acpi_soft_cpu_dead(unsigned int cpu)
137{
138 struct acpi_processor *pr = per_cpu(processors, cpu);
139
140 if (!pr || !acpi_fetch_acpi_dev(handle: pr->handle))
141 return 0;
142
143 acpi_processor_reevaluate_tstate(pr, is_dead: true);
144 return 0;
145}
146
147#ifdef CONFIG_ACPI_CPU_FREQ_PSS
148static void acpi_pss_perf_init(struct acpi_processor *pr)
149{
150 acpi_processor_ppc_has_changed(pr, event_flag: 0);
151
152 acpi_processor_get_throttling_info(pr);
153
154 if (pr->flags.throttling)
155 pr->flags.limit = 1;
156}
157#else
158static inline void acpi_pss_perf_init(struct acpi_processor *pr) {}
159#endif /* CONFIG_ACPI_CPU_FREQ_PSS */
160
161static int __acpi_processor_start(struct acpi_device *device)
162{
163 struct acpi_processor *pr = acpi_driver_data(d: device);
164 acpi_status status;
165 int result = 0;
166
167 if (!pr)
168 return -ENODEV;
169
170 if (pr->flags.need_hotplug_init)
171 return 0;
172
173 result = acpi_cppc_processor_probe(pr);
174 if (result && !IS_ENABLED(CONFIG_ACPI_CPU_FREQ_PSS))
175 dev_dbg(&device->dev, "CPPC data invalid or not present\n");
176
177 if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
178 acpi_processor_power_init(pr);
179
180 acpi_pss_perf_init(pr);
181
182 result = acpi_processor_thermal_init(pr, device);
183 if (result)
184 goto err_power_exit;
185
186 status = acpi_install_notify_handler(device: device->handle, ACPI_DEVICE_NOTIFY,
187 handler: acpi_processor_notify, context: device);
188 if (ACPI_SUCCESS(status))
189 return 0;
190
191 result = -ENODEV;
192 acpi_processor_thermal_exit(pr, device);
193
194err_power_exit:
195 acpi_processor_power_exit(pr);
196 return result;
197}
198
199static int acpi_processor_start(struct device *dev)
200{
201 struct acpi_device *device = ACPI_COMPANION(dev);
202 int ret;
203
204 if (!device)
205 return -ENODEV;
206
207 /* Protect against concurrent CPU hotplug operations */
208 cpu_hotplug_disable();
209 ret = __acpi_processor_start(device);
210 cpu_hotplug_enable();
211 return ret;
212}
213
214static int acpi_processor_stop(struct device *dev)
215{
216 struct acpi_device *device = ACPI_COMPANION(dev);
217 struct acpi_processor *pr;
218
219 if (!device)
220 return 0;
221
222 acpi_remove_notify_handler(device: device->handle, ACPI_DEVICE_NOTIFY,
223 handler: acpi_processor_notify);
224
225 pr = acpi_driver_data(d: device);
226 if (!pr)
227 return 0;
228 acpi_processor_power_exit(pr);
229
230 acpi_cppc_processor_exit(pr);
231
232 acpi_processor_thermal_exit(pr, device);
233
234 return 0;
235}
236
237bool acpi_processor_cpufreq_init;
238
239static int acpi_processor_notifier(struct notifier_block *nb,
240 unsigned long event, void *data)
241{
242 struct cpufreq_policy *policy = data;
243
244 if (event == CPUFREQ_CREATE_POLICY) {
245 acpi_thermal_cpufreq_init(policy);
246 acpi_processor_ppc_init(policy);
247 } else if (event == CPUFREQ_REMOVE_POLICY) {
248 acpi_processor_ppc_exit(policy);
249 acpi_thermal_cpufreq_exit(policy);
250 }
251
252 return 0;
253}
254
255static struct notifier_block acpi_processor_notifier_block = {
256 .notifier_call = acpi_processor_notifier,
257};
258
259/*
260 * We keep the driver loaded even when ACPI is not running.
261 * This is needed for the powernow-k8 driver, that works even without
262 * ACPI, but needs symbols from this driver
263 */
264static enum cpuhp_state hp_online;
265static int __init acpi_processor_driver_init(void)
266{
267 int result = 0;
268
269 if (acpi_disabled)
270 return 0;
271
272 if (!cpufreq_register_notifier(nb: &acpi_processor_notifier_block,
273 CPUFREQ_POLICY_NOTIFIER)) {
274 acpi_processor_cpufreq_init = true;
275 acpi_processor_ignore_ppc_init();
276 }
277
278 result = driver_register(drv: &acpi_processor_driver);
279 if (result < 0)
280 return result;
281
282 result = cpuhp_setup_state_nocalls(state: CPUHP_AP_ONLINE_DYN,
283 name: "acpi/cpu-drv:online",
284 startup: acpi_soft_cpu_online, NULL);
285 if (result < 0)
286 goto err;
287 hp_online = result;
288 cpuhp_setup_state_nocalls(state: CPUHP_ACPI_CPUDRV_DEAD, name: "acpi/cpu-drv:dead",
289 NULL, teardown: acpi_soft_cpu_dead);
290
291 acpi_processor_throttling_init();
292 return 0;
293err:
294 driver_unregister(drv: &acpi_processor_driver);
295 return result;
296}
297
298static void __exit acpi_processor_driver_exit(void)
299{
300 if (acpi_disabled)
301 return;
302
303 if (acpi_processor_cpufreq_init) {
304 cpufreq_unregister_notifier(nb: &acpi_processor_notifier_block,
305 CPUFREQ_POLICY_NOTIFIER);
306 acpi_processor_cpufreq_init = false;
307 }
308
309 cpuhp_remove_state_nocalls(state: hp_online);
310 cpuhp_remove_state_nocalls(state: CPUHP_ACPI_CPUDRV_DEAD);
311 driver_unregister(drv: &acpi_processor_driver);
312}
313
314module_init(acpi_processor_driver_init);
315module_exit(acpi_processor_driver_exit);
316
317MODULE_ALIAS("processor");
318

source code of linux/drivers/acpi/processor_driver.c