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 
31 MODULE_AUTHOR("Paul Diefenbaugh");
32 MODULE_DESCRIPTION("ACPI Processor Driver");
33 MODULE_LICENSE("GPL");
34 
35 static int acpi_processor_start(struct device *dev);
36 static int acpi_processor_stop(struct device *dev);
37 
38 static const struct acpi_device_id processor_device_ids[] = {
39 	{ACPI_PROCESSOR_OBJECT_HID, 0},
40 	{ACPI_PROCESSOR_DEVICE_HID, 0},
41 	{"", 0},
42 };
43 MODULE_DEVICE_TABLE(acpi, processor_device_ids);
44 
45 static struct device_driver acpi_processor_driver = {
46 	.name = "processor",
47 	.bus = &cpu_subsys,
48 	.acpi_match_table = processor_device_ids,
49 	.probe = acpi_processor_start,
50 	.remove = acpi_processor_stop,
51 };
52 
53 static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
54 {
55 	struct acpi_device *device = data;
56 	struct acpi_processor *pr;
57 	int saved;
58 
59 	if (device->handle != handle)
60 		return;
61 
62 	pr = acpi_driver_data(device);
63 	if (!pr)
64 		return;
65 
66 	switch (event) {
67 	case ACPI_PROCESSOR_NOTIFY_PERFORMANCE:
68 		saved = pr->performance_platform_limit;
69 		acpi_processor_ppc_has_changed(pr, 1);
70 		if (saved == pr->performance_platform_limit)
71 			break;
72 		acpi_bus_generate_netlink_event(device->pnp.device_class,
73 						  dev_name(&device->dev), event,
74 						  pr->performance_platform_limit);
75 		break;
76 	case ACPI_PROCESSOR_NOTIFY_POWER:
77 		acpi_processor_power_state_has_changed(pr);
78 		acpi_bus_generate_netlink_event(device->pnp.device_class,
79 						  dev_name(&device->dev), event, 0);
80 		break;
81 	case ACPI_PROCESSOR_NOTIFY_THROTTLING:
82 		acpi_processor_tstate_has_changed(pr);
83 		acpi_bus_generate_netlink_event(device->pnp.device_class,
84 						  dev_name(&device->dev), event, 0);
85 		break;
86 	default:
87 		acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
88 		break;
89 	}
90 
91 	return;
92 }
93 
94 static int __acpi_processor_start(struct acpi_device *device);
95 
96 static int acpi_soft_cpu_online(unsigned int cpu)
97 {
98 	struct acpi_processor *pr = per_cpu(processors, cpu);
99 	struct acpi_device *device;
100 
101 	if (!pr || acpi_bus_get_device(pr->handle, &device))
102 		return 0;
103 	/*
104 	 * CPU got physically hotplugged and onlined for the first time:
105 	 * Initialize missing things.
106 	 */
107 	if (pr->flags.need_hotplug_init) {
108 		int ret;
109 
110 		pr_info("Will online and init hotplugged CPU: %d\n",
111 			pr->id);
112 		pr->flags.need_hotplug_init = 0;
113 		ret = __acpi_processor_start(device);
114 		WARN(ret, "Failed to start CPU: %d\n", pr->id);
115 	} else {
116 		/* Normal CPU soft online event. */
117 		acpi_processor_ppc_has_changed(pr, 0);
118 		acpi_processor_hotplug(pr);
119 		acpi_processor_reevaluate_tstate(pr, false);
120 		acpi_processor_tstate_has_changed(pr);
121 	}
122 	return 0;
123 }
124 
125 static int acpi_soft_cpu_dead(unsigned int cpu)
126 {
127 	struct acpi_processor *pr = per_cpu(processors, cpu);
128 	struct acpi_device *device;
129 
130 	if (!pr || acpi_bus_get_device(pr->handle, &device))
131 		return 0;
132 
133 	acpi_processor_reevaluate_tstate(pr, true);
134 	return 0;
135 }
136 
137 #ifdef CONFIG_ACPI_CPU_FREQ_PSS
138 static int acpi_pss_perf_init(struct acpi_processor *pr,
139 		struct acpi_device *device)
140 {
141 	int result = 0;
142 
143 	acpi_processor_ppc_has_changed(pr, 0);
144 
145 	acpi_processor_get_throttling_info(pr);
146 
147 	if (pr->flags.throttling)
148 		pr->flags.limit = 1;
149 
150 	pr->cdev = thermal_cooling_device_register("Processor", device,
151 						   &processor_cooling_ops);
152 	if (IS_ERR(pr->cdev)) {
153 		result = PTR_ERR(pr->cdev);
154 		return result;
155 	}
156 
157 	dev_dbg(&device->dev, "registered as cooling_device%d\n",
158 		pr->cdev->id);
159 
160 	result = sysfs_create_link(&device->dev.kobj,
161 				   &pr->cdev->device.kobj,
162 				   "thermal_cooling");
163 	if (result) {
164 		dev_err(&device->dev,
165 			"Failed to create sysfs link 'thermal_cooling'\n");
166 		goto err_thermal_unregister;
167 	}
168 
169 	result = sysfs_create_link(&pr->cdev->device.kobj,
170 				   &device->dev.kobj,
171 				   "device");
172 	if (result) {
173 		dev_err(&pr->cdev->device,
174 			"Failed to create sysfs link 'device'\n");
175 		goto err_remove_sysfs_thermal;
176 	}
177 
178 	return 0;
179 
180  err_remove_sysfs_thermal:
181 	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
182  err_thermal_unregister:
183 	thermal_cooling_device_unregister(pr->cdev);
184 
185 	return result;
186 }
187 
188 static void acpi_pss_perf_exit(struct acpi_processor *pr,
189 		struct acpi_device *device)
190 {
191 	if (pr->cdev) {
192 		sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
193 		sysfs_remove_link(&pr->cdev->device.kobj, "device");
194 		thermal_cooling_device_unregister(pr->cdev);
195 		pr->cdev = NULL;
196 	}
197 }
198 #else
199 static inline int acpi_pss_perf_init(struct acpi_processor *pr,
200 		struct acpi_device *device)
201 {
202 	return 0;
203 }
204 
205 static inline void acpi_pss_perf_exit(struct acpi_processor *pr,
206 		struct acpi_device *device) {}
207 #endif /* CONFIG_ACPI_CPU_FREQ_PSS */
208 
209 static int __acpi_processor_start(struct acpi_device *device)
210 {
211 	struct acpi_processor *pr = acpi_driver_data(device);
212 	acpi_status status;
213 	int result = 0;
214 
215 	if (!pr)
216 		return -ENODEV;
217 
218 	if (pr->flags.need_hotplug_init)
219 		return 0;
220 
221 	result = acpi_cppc_processor_probe(pr);
222 	if (result && !IS_ENABLED(CONFIG_ACPI_CPU_FREQ_PSS))
223 		dev_dbg(&device->dev, "CPPC data invalid or not present\n");
224 
225 	if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
226 		acpi_processor_power_init(pr);
227 
228 	result = acpi_pss_perf_init(pr, device);
229 	if (result)
230 		goto err_power_exit;
231 
232 	status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
233 					     acpi_processor_notify, device);
234 	if (ACPI_SUCCESS(status))
235 		return 0;
236 
237 	result = -ENODEV;
238 	acpi_pss_perf_exit(pr, device);
239 
240 err_power_exit:
241 	acpi_processor_power_exit(pr);
242 	return result;
243 }
244 
245 static int acpi_processor_start(struct device *dev)
246 {
247 	struct acpi_device *device = ACPI_COMPANION(dev);
248 	int ret;
249 
250 	if (!device)
251 		return -ENODEV;
252 
253 	/* Protect against concurrent CPU hotplug operations */
254 	cpu_hotplug_disable();
255 	ret = __acpi_processor_start(device);
256 	cpu_hotplug_enable();
257 	return ret;
258 }
259 
260 static int acpi_processor_stop(struct device *dev)
261 {
262 	struct acpi_device *device = ACPI_COMPANION(dev);
263 	struct acpi_processor *pr;
264 
265 	if (!device)
266 		return 0;
267 
268 	acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
269 				   acpi_processor_notify);
270 
271 	pr = acpi_driver_data(device);
272 	if (!pr)
273 		return 0;
274 	acpi_processor_power_exit(pr);
275 
276 	acpi_pss_perf_exit(pr, device);
277 
278 	acpi_cppc_processor_exit(pr);
279 
280 	return 0;
281 }
282 
283 bool acpi_processor_cpufreq_init;
284 
285 static int acpi_processor_notifier(struct notifier_block *nb,
286 				   unsigned long event, void *data)
287 {
288 	struct cpufreq_policy *policy = data;
289 
290 	if (event == CPUFREQ_CREATE_POLICY) {
291 		acpi_thermal_cpufreq_init(policy);
292 		acpi_processor_ppc_init(policy);
293 	} else if (event == CPUFREQ_REMOVE_POLICY) {
294 		acpi_processor_ppc_exit(policy);
295 		acpi_thermal_cpufreq_exit(policy);
296 	}
297 
298 	return 0;
299 }
300 
301 static struct notifier_block acpi_processor_notifier_block = {
302 	.notifier_call = acpi_processor_notifier,
303 };
304 
305 /*
306  * We keep the driver loaded even when ACPI is not running.
307  * This is needed for the powernow-k8 driver, that works even without
308  * ACPI, but needs symbols from this driver
309  */
310 static enum cpuhp_state hp_online;
311 static int __init acpi_processor_driver_init(void)
312 {
313 	int result = 0;
314 
315 	if (acpi_disabled)
316 		return 0;
317 
318 	result = driver_register(&acpi_processor_driver);
319 	if (result < 0)
320 		return result;
321 
322 	result = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
323 					   "acpi/cpu-drv:online",
324 					   acpi_soft_cpu_online, NULL);
325 	if (result < 0)
326 		goto err;
327 	hp_online = result;
328 	cpuhp_setup_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD, "acpi/cpu-drv:dead",
329 				  NULL, acpi_soft_cpu_dead);
330 
331 	if (!cpufreq_register_notifier(&acpi_processor_notifier_block,
332 				       CPUFREQ_POLICY_NOTIFIER)) {
333 		acpi_processor_cpufreq_init = true;
334 		acpi_processor_ignore_ppc_init();
335 	}
336 
337 	acpi_processor_throttling_init();
338 	return 0;
339 err:
340 	driver_unregister(&acpi_processor_driver);
341 	return result;
342 }
343 
344 static void __exit acpi_processor_driver_exit(void)
345 {
346 	if (acpi_disabled)
347 		return;
348 
349 	if (acpi_processor_cpufreq_init) {
350 		cpufreq_unregister_notifier(&acpi_processor_notifier_block,
351 					    CPUFREQ_POLICY_NOTIFIER);
352 		acpi_processor_cpufreq_init = false;
353 	}
354 
355 	cpuhp_remove_state_nocalls(hp_online);
356 	cpuhp_remove_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD);
357 	driver_unregister(&acpi_processor_driver);
358 }
359 
360 module_init(acpi_processor_driver_init);
361 module_exit(acpi_processor_driver_exit);
362 
363 MODULE_ALIAS("processor");
364