1 /*
2  * processor_driver.c - ACPI Processor Driver
3  *
4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6  *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
7  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
8  *  			- Added processor hotplug support
9  *  Copyright (C) 2013, Intel Corporation
10  *                      Rafael J. Wysocki <rafael.j.wysocki@intel.com>
11  *
12  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
13  *
14  *  This program is free software; you can redistribute it and/or modify
15  *  it under the terms of the GNU General Public License as published by
16  *  the Free Software Foundation; either version 2 of the License, or (at
17  *  your option) any later version.
18  *
19  *  This program is distributed in the hope that it will be useful, but
20  *  WITHOUT ANY WARRANTY; without even the implied warranty of
21  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
22  *  General Public License for more details.
23  *
24  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
25  */
26 
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/init.h>
30 #include <linux/cpufreq.h>
31 #include <linux/cpu.h>
32 #include <linux/cpuidle.h>
33 #include <linux/slab.h>
34 #include <linux/acpi.h>
35 
36 #include <acpi/processor.h>
37 
38 #include "internal.h"
39 
40 #define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
41 #define ACPI_PROCESSOR_NOTIFY_POWER	0x81
42 #define ACPI_PROCESSOR_NOTIFY_THROTTLING	0x82
43 
44 #define _COMPONENT		ACPI_PROCESSOR_COMPONENT
45 ACPI_MODULE_NAME("processor_driver");
46 
47 MODULE_AUTHOR("Paul Diefenbaugh");
48 MODULE_DESCRIPTION("ACPI Processor Driver");
49 MODULE_LICENSE("GPL");
50 
51 static int acpi_processor_start(struct device *dev);
52 static int acpi_processor_stop(struct device *dev);
53 
54 static const struct acpi_device_id processor_device_ids[] = {
55 	{ACPI_PROCESSOR_OBJECT_HID, 0},
56 	{ACPI_PROCESSOR_DEVICE_HID, 0},
57 	{"", 0},
58 };
59 MODULE_DEVICE_TABLE(acpi, processor_device_ids);
60 
61 static struct device_driver acpi_processor_driver = {
62 	.name = "processor",
63 	.bus = &cpu_subsys,
64 	.acpi_match_table = processor_device_ids,
65 	.probe = acpi_processor_start,
66 	.remove = acpi_processor_stop,
67 };
68 
69 static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
70 {
71 	struct acpi_device *device = data;
72 	struct acpi_processor *pr;
73 	int saved;
74 
75 	if (device->handle != handle)
76 		return;
77 
78 	pr = acpi_driver_data(device);
79 	if (!pr)
80 		return;
81 
82 	switch (event) {
83 	case ACPI_PROCESSOR_NOTIFY_PERFORMANCE:
84 		saved = pr->performance_platform_limit;
85 		acpi_processor_ppc_has_changed(pr, 1);
86 		if (saved == pr->performance_platform_limit)
87 			break;
88 		acpi_bus_generate_netlink_event(device->pnp.device_class,
89 						  dev_name(&device->dev), event,
90 						  pr->performance_platform_limit);
91 		break;
92 	case ACPI_PROCESSOR_NOTIFY_POWER:
93 		acpi_processor_power_state_has_changed(pr);
94 		acpi_bus_generate_netlink_event(device->pnp.device_class,
95 						  dev_name(&device->dev), event, 0);
96 		break;
97 	case ACPI_PROCESSOR_NOTIFY_THROTTLING:
98 		acpi_processor_tstate_has_changed(pr);
99 		acpi_bus_generate_netlink_event(device->pnp.device_class,
100 						  dev_name(&device->dev), event, 0);
101 		break;
102 	default:
103 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
104 				  "Unsupported event [0x%x]\n", event));
105 		break;
106 	}
107 
108 	return;
109 }
110 
111 static int __acpi_processor_start(struct acpi_device *device);
112 
113 static int acpi_soft_cpu_online(unsigned int cpu)
114 {
115 	struct acpi_processor *pr = per_cpu(processors, cpu);
116 	struct acpi_device *device;
117 
118 	if (!pr || acpi_bus_get_device(pr->handle, &device))
119 		return 0;
120 	/*
121 	 * CPU got physically hotplugged and onlined for the first time:
122 	 * Initialize missing things.
123 	 */
124 	if (pr->flags.need_hotplug_init) {
125 		int ret;
126 
127 		pr_info("Will online and init hotplugged CPU: %d\n",
128 			pr->id);
129 		pr->flags.need_hotplug_init = 0;
130 		ret = __acpi_processor_start(device);
131 		WARN(ret, "Failed to start CPU: %d\n", pr->id);
132 	} else {
133 		/* Normal CPU soft online event. */
134 		acpi_processor_ppc_has_changed(pr, 0);
135 		acpi_processor_hotplug(pr);
136 		acpi_processor_reevaluate_tstate(pr, false);
137 		acpi_processor_tstate_has_changed(pr);
138 	}
139 	return 0;
140 }
141 
142 static int acpi_soft_cpu_dead(unsigned int cpu)
143 {
144 	struct acpi_processor *pr = per_cpu(processors, cpu);
145 	struct acpi_device *device;
146 
147 	if (!pr || acpi_bus_get_device(pr->handle, &device))
148 		return 0;
149 
150 	acpi_processor_reevaluate_tstate(pr, true);
151 	return 0;
152 }
153 
154 #ifdef CONFIG_ACPI_CPU_FREQ_PSS
155 static int acpi_pss_perf_init(struct acpi_processor *pr,
156 		struct acpi_device *device)
157 {
158 	int result = 0;
159 
160 	acpi_processor_ppc_has_changed(pr, 0);
161 
162 	acpi_processor_get_throttling_info(pr);
163 
164 	if (pr->flags.throttling)
165 		pr->flags.limit = 1;
166 
167 	pr->cdev = thermal_cooling_device_register("Processor", device,
168 						   &processor_cooling_ops);
169 	if (IS_ERR(pr->cdev)) {
170 		result = PTR_ERR(pr->cdev);
171 		return result;
172 	}
173 
174 	dev_dbg(&device->dev, "registered as cooling_device%d\n",
175 		pr->cdev->id);
176 
177 	result = sysfs_create_link(&device->dev.kobj,
178 				   &pr->cdev->device.kobj,
179 				   "thermal_cooling");
180 	if (result) {
181 		dev_err(&device->dev,
182 			"Failed to create sysfs link 'thermal_cooling'\n");
183 		goto err_thermal_unregister;
184 	}
185 
186 	result = sysfs_create_link(&pr->cdev->device.kobj,
187 				   &device->dev.kobj,
188 				   "device");
189 	if (result) {
190 		dev_err(&pr->cdev->device,
191 			"Failed to create sysfs link 'device'\n");
192 		goto err_remove_sysfs_thermal;
193 	}
194 
195 	return 0;
196 
197  err_remove_sysfs_thermal:
198 	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
199  err_thermal_unregister:
200 	thermal_cooling_device_unregister(pr->cdev);
201 
202 	return result;
203 }
204 
205 static void acpi_pss_perf_exit(struct acpi_processor *pr,
206 		struct acpi_device *device)
207 {
208 	if (pr->cdev) {
209 		sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
210 		sysfs_remove_link(&pr->cdev->device.kobj, "device");
211 		thermal_cooling_device_unregister(pr->cdev);
212 		pr->cdev = NULL;
213 	}
214 }
215 #else
216 static inline int acpi_pss_perf_init(struct acpi_processor *pr,
217 		struct acpi_device *device)
218 {
219 	return 0;
220 }
221 
222 static inline void acpi_pss_perf_exit(struct acpi_processor *pr,
223 		struct acpi_device *device) {}
224 #endif /* CONFIG_ACPI_CPU_FREQ_PSS */
225 
226 static int __acpi_processor_start(struct acpi_device *device)
227 {
228 	struct acpi_processor *pr = acpi_driver_data(device);
229 	acpi_status status;
230 	int result = 0;
231 
232 	if (!pr)
233 		return -ENODEV;
234 
235 	if (pr->flags.need_hotplug_init)
236 		return 0;
237 
238 	result = acpi_cppc_processor_probe(pr);
239 	if (result && !IS_ENABLED(CONFIG_ACPI_CPU_FREQ_PSS))
240 		dev_warn(&device->dev, "CPPC data invalid or not present\n");
241 
242 	if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
243 		acpi_processor_power_init(pr);
244 
245 	result = acpi_pss_perf_init(pr, device);
246 	if (result)
247 		goto err_power_exit;
248 
249 	status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
250 					     acpi_processor_notify, device);
251 	if (ACPI_SUCCESS(status))
252 		return 0;
253 
254 	result = -ENODEV;
255 	acpi_pss_perf_exit(pr, device);
256 
257 err_power_exit:
258 	acpi_processor_power_exit(pr);
259 	return result;
260 }
261 
262 static int acpi_processor_start(struct device *dev)
263 {
264 	struct acpi_device *device = ACPI_COMPANION(dev);
265 	int ret;
266 
267 	if (!device)
268 		return -ENODEV;
269 
270 	/* Protect against concurrent CPU hotplug operations */
271 	cpu_hotplug_disable();
272 	ret = __acpi_processor_start(device);
273 	cpu_hotplug_enable();
274 	return ret;
275 }
276 
277 static int acpi_processor_stop(struct device *dev)
278 {
279 	struct acpi_device *device = ACPI_COMPANION(dev);
280 	struct acpi_processor *pr;
281 
282 	if (!device)
283 		return 0;
284 
285 	acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
286 				   acpi_processor_notify);
287 
288 	pr = acpi_driver_data(device);
289 	if (!pr)
290 		return 0;
291 	acpi_processor_power_exit(pr);
292 
293 	acpi_pss_perf_exit(pr, device);
294 
295 	acpi_cppc_processor_exit(pr);
296 
297 	return 0;
298 }
299 
300 /*
301  * We keep the driver loaded even when ACPI is not running.
302  * This is needed for the powernow-k8 driver, that works even without
303  * ACPI, but needs symbols from this driver
304  */
305 static enum cpuhp_state hp_online;
306 static int __init acpi_processor_driver_init(void)
307 {
308 	int result = 0;
309 
310 	if (acpi_disabled)
311 		return 0;
312 
313 	result = driver_register(&acpi_processor_driver);
314 	if (result < 0)
315 		return result;
316 
317 	result = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
318 					   "acpi/cpu-drv:online",
319 					   acpi_soft_cpu_online, NULL);
320 	if (result < 0)
321 		goto err;
322 	hp_online = result;
323 	cpuhp_setup_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD, "acpi/cpu-drv:dead",
324 				  NULL, acpi_soft_cpu_dead);
325 
326 	acpi_thermal_cpufreq_init();
327 	acpi_processor_ppc_init();
328 	acpi_processor_throttling_init();
329 	return 0;
330 err:
331 	driver_unregister(&acpi_processor_driver);
332 	return result;
333 }
334 
335 static void __exit acpi_processor_driver_exit(void)
336 {
337 	if (acpi_disabled)
338 		return;
339 
340 	acpi_processor_ppc_exit();
341 	acpi_thermal_cpufreq_exit();
342 	cpuhp_remove_state_nocalls(hp_online);
343 	cpuhp_remove_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD);
344 	driver_unregister(&acpi_processor_driver);
345 }
346 
347 module_init(acpi_processor_driver_init);
348 module_exit(acpi_processor_driver_exit);
349 
350 MODULE_ALIAS("processor");
351