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_cst_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_cpu_soft_notify(struct notifier_block *nfb,
114 					  unsigned long action, void *hcpu)
115 {
116 	unsigned int cpu = (unsigned long)hcpu;
117 	struct acpi_processor *pr = per_cpu(processors, cpu);
118 	struct acpi_device *device;
119 	action &= ~CPU_TASKS_FROZEN;
120 
121 	/*
122 	 * CPU_STARTING and CPU_DYING must not sleep. Return here since
123 	 * acpi_bus_get_device() may sleep.
124 	 */
125 	if (action == CPU_STARTING || action == CPU_DYING)
126 		return NOTIFY_DONE;
127 
128 	if (!pr || acpi_bus_get_device(pr->handle, &device))
129 		return NOTIFY_DONE;
130 
131 	if (action == CPU_ONLINE) {
132 		/*
133 		 * CPU got physically hotplugged and onlined for the first time:
134 		 * Initialize missing things.
135 		 */
136 		if (pr->flags.need_hotplug_init) {
137 			int ret;
138 
139 			pr_info("Will online and init hotplugged CPU: %d\n",
140 				pr->id);
141 			pr->flags.need_hotplug_init = 0;
142 			ret = __acpi_processor_start(device);
143 			WARN(ret, "Failed to start CPU: %d\n", pr->id);
144 		} else {
145 			/* Normal CPU soft online event. */
146 			acpi_processor_ppc_has_changed(pr, 0);
147 			acpi_processor_hotplug(pr);
148 			acpi_processor_reevaluate_tstate(pr, action);
149 			acpi_processor_tstate_has_changed(pr);
150 		}
151 	} else if (action == CPU_DEAD) {
152 		/* Invalidate flag.throttling after the CPU is offline. */
153 		acpi_processor_reevaluate_tstate(pr, action);
154 	}
155 	return NOTIFY_OK;
156 }
157 
158 static struct notifier_block acpi_cpu_notifier = {
159 	    .notifier_call = acpi_cpu_soft_notify,
160 };
161 
162 #ifdef CONFIG_ACPI_CPU_FREQ_PSS
163 static int acpi_pss_perf_init(struct acpi_processor *pr,
164 		struct acpi_device *device)
165 {
166 	int result = 0;
167 
168 	acpi_processor_ppc_has_changed(pr, 0);
169 
170 	acpi_processor_get_throttling_info(pr);
171 
172 	if (pr->flags.throttling)
173 		pr->flags.limit = 1;
174 
175 	pr->cdev = thermal_cooling_device_register("Processor", device,
176 						   &processor_cooling_ops);
177 	if (IS_ERR(pr->cdev)) {
178 		result = PTR_ERR(pr->cdev);
179 		return result;
180 	}
181 
182 	dev_dbg(&device->dev, "registered as cooling_device%d\n",
183 		pr->cdev->id);
184 
185 	result = sysfs_create_link(&device->dev.kobj,
186 				   &pr->cdev->device.kobj,
187 				   "thermal_cooling");
188 	if (result) {
189 		dev_err(&device->dev,
190 			"Failed to create sysfs link 'thermal_cooling'\n");
191 		goto err_thermal_unregister;
192 	}
193 
194 	result = sysfs_create_link(&pr->cdev->device.kobj,
195 				   &device->dev.kobj,
196 				   "device");
197 	if (result) {
198 		dev_err(&pr->cdev->device,
199 			"Failed to create sysfs link 'device'\n");
200 		goto err_remove_sysfs_thermal;
201 	}
202 
203 	return 0;
204 
205  err_remove_sysfs_thermal:
206 	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
207  err_thermal_unregister:
208 	thermal_cooling_device_unregister(pr->cdev);
209 
210 	return result;
211 }
212 
213 static void acpi_pss_perf_exit(struct acpi_processor *pr,
214 		struct acpi_device *device)
215 {
216 	if (pr->cdev) {
217 		sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
218 		sysfs_remove_link(&pr->cdev->device.kobj, "device");
219 		thermal_cooling_device_unregister(pr->cdev);
220 		pr->cdev = NULL;
221 	}
222 }
223 #else
224 static inline int acpi_pss_perf_init(struct acpi_processor *pr,
225 		struct acpi_device *device)
226 {
227 	return 0;
228 }
229 
230 static inline void acpi_pss_perf_exit(struct acpi_processor *pr,
231 		struct acpi_device *device) {}
232 #endif /* CONFIG_ACPI_CPU_FREQ_PSS */
233 
234 static int __acpi_processor_start(struct acpi_device *device)
235 {
236 	struct acpi_processor *pr = acpi_driver_data(device);
237 	acpi_status status;
238 	int result = 0;
239 
240 	if (!pr)
241 		return -ENODEV;
242 
243 	if (pr->flags.need_hotplug_init)
244 		return 0;
245 
246 	result = acpi_cppc_processor_probe(pr);
247 	if (result)
248 		return -ENODEV;
249 
250 	if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
251 		acpi_processor_power_init(pr);
252 
253 	result = acpi_pss_perf_init(pr, device);
254 	if (result)
255 		goto err_power_exit;
256 
257 	status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
258 					     acpi_processor_notify, device);
259 	if (ACPI_SUCCESS(status))
260 		return 0;
261 
262 err_power_exit:
263 	acpi_processor_power_exit(pr);
264 	return result;
265 }
266 
267 static int acpi_processor_start(struct device *dev)
268 {
269 	struct acpi_device *device = ACPI_COMPANION(dev);
270 
271 	if (!device)
272 		return -ENODEV;
273 
274 	return __acpi_processor_start(device);
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 
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 	register_hotcpu_notifier(&acpi_cpu_notifier);
318 	acpi_thermal_cpufreq_init();
319 	acpi_processor_ppc_init();
320 	acpi_processor_throttling_init();
321 	return 0;
322 }
323 
324 static void __exit acpi_processor_driver_exit(void)
325 {
326 	if (acpi_disabled)
327 		return;
328 
329 	acpi_processor_ppc_exit();
330 	acpi_thermal_cpufreq_exit();
331 	unregister_hotcpu_notifier(&acpi_cpu_notifier);
332 	driver_unregister(&acpi_processor_driver);
333 }
334 
335 module_init(acpi_processor_driver_init);
336 module_exit(acpi_processor_driver_exit);
337 
338 MODULE_ALIAS("processor");
339