xref: /linux/drivers/acpi/processor_driver.c (revision 3932b9ca55b0be314a36d3e84faff3e823c081f5) 
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  *  You should have received a copy of the GNU General Public License along
25  *  with this program; if not, write to the Free Software Foundation, Inc.,
26  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
27  *
28  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
29  */
30 
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/init.h>
34 #include <linux/cpufreq.h>
35 #include <linux/cpu.h>
36 #include <linux/cpuidle.h>
37 #include <linux/slab.h>
38 #include <linux/acpi.h>
39 
40 #include <acpi/processor.h>
41 
42 #include "internal.h"
43 
44 #define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
45 #define ACPI_PROCESSOR_NOTIFY_POWER	0x81
46 #define ACPI_PROCESSOR_NOTIFY_THROTTLING	0x82
47 
48 #define _COMPONENT		ACPI_PROCESSOR_COMPONENT
49 ACPI_MODULE_NAME("processor_driver");
50 
51 MODULE_AUTHOR("Paul Diefenbaugh");
52 MODULE_DESCRIPTION("ACPI Processor Driver");
53 MODULE_LICENSE("GPL");
54 
55 static int acpi_processor_start(struct device *dev);
56 static int acpi_processor_stop(struct device *dev);
57 
58 static const struct acpi_device_id processor_device_ids[] = {
59 	{ACPI_PROCESSOR_OBJECT_HID, 0},
60 	{ACPI_PROCESSOR_DEVICE_HID, 0},
61 	{"", 0},
62 };
63 MODULE_DEVICE_TABLE(acpi, processor_device_ids);
64 
65 static struct device_driver acpi_processor_driver = {
66 	.name = "processor",
67 	.bus = &cpu_subsys,
68 	.acpi_match_table = processor_device_ids,
69 	.probe = acpi_processor_start,
70 	.remove = acpi_processor_stop,
71 };
72 
73 static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
74 {
75 	struct acpi_device *device = data;
76 	struct acpi_processor *pr;
77 	int saved;
78 
79 	if (device->handle != handle)
80 		return;
81 
82 	pr = acpi_driver_data(device);
83 	if (!pr)
84 		return;
85 
86 	switch (event) {
87 	case ACPI_PROCESSOR_NOTIFY_PERFORMANCE:
88 		saved = pr->performance_platform_limit;
89 		acpi_processor_ppc_has_changed(pr, 1);
90 		if (saved == pr->performance_platform_limit)
91 			break;
92 		acpi_bus_generate_netlink_event(device->pnp.device_class,
93 						  dev_name(&device->dev), event,
94 						  pr->performance_platform_limit);
95 		break;
96 	case ACPI_PROCESSOR_NOTIFY_POWER:
97 		acpi_processor_cst_has_changed(pr);
98 		acpi_bus_generate_netlink_event(device->pnp.device_class,
99 						  dev_name(&device->dev), event, 0);
100 		break;
101 	case ACPI_PROCESSOR_NOTIFY_THROTTLING:
102 		acpi_processor_tstate_has_changed(pr);
103 		acpi_bus_generate_netlink_event(device->pnp.device_class,
104 						  dev_name(&device->dev), event, 0);
105 		break;
106 	default:
107 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
108 				  "Unsupported event [0x%x]\n", event));
109 		break;
110 	}
111 
112 	return;
113 }
114 
115 static int __acpi_processor_start(struct acpi_device *device);
116 
117 static int acpi_cpu_soft_notify(struct notifier_block *nfb,
118 					  unsigned long action, void *hcpu)
119 {
120 	unsigned int cpu = (unsigned long)hcpu;
121 	struct acpi_processor *pr = per_cpu(processors, cpu);
122 	struct acpi_device *device;
123 	action &= ~CPU_TASKS_FROZEN;
124 
125 	/*
126 	 * CPU_STARTING and CPU_DYING must not sleep. Return here since
127 	 * acpi_bus_get_device() may sleep.
128 	 */
129 	if (action == CPU_STARTING || action == CPU_DYING)
130 		return NOTIFY_DONE;
131 
132 	if (!pr || acpi_bus_get_device(pr->handle, &device))
133 		return NOTIFY_DONE;
134 
135 	if (action == CPU_ONLINE) {
136 		/*
137 		 * CPU got physically hotplugged and onlined for the first time:
138 		 * Initialize missing things.
139 		 */
140 		if (pr->flags.need_hotplug_init) {
141 			int ret;
142 
143 			pr_info("Will online and init hotplugged CPU: %d\n",
144 				pr->id);
145 			pr->flags.need_hotplug_init = 0;
146 			ret = __acpi_processor_start(device);
147 			WARN(ret, "Failed to start CPU: %d\n", pr->id);
148 		} else {
149 			/* Normal CPU soft online event. */
150 			acpi_processor_ppc_has_changed(pr, 0);
151 			acpi_processor_hotplug(pr);
152 			acpi_processor_reevaluate_tstate(pr, action);
153 			acpi_processor_tstate_has_changed(pr);
154 		}
155 	} else if (action == CPU_DEAD) {
156 		/* Invalidate flag.throttling after the CPU is offline. */
157 		acpi_processor_reevaluate_tstate(pr, action);
158 	}
159 	return NOTIFY_OK;
160 }
161 
162 static struct notifier_block __refdata acpi_cpu_notifier = {
163 	    .notifier_call = acpi_cpu_soft_notify,
164 };
165 
166 static int __acpi_processor_start(struct acpi_device *device)
167 {
168 	struct acpi_processor *pr = acpi_driver_data(device);
169 	acpi_status status;
170 	int result = 0;
171 
172 	if (!pr)
173 		return -ENODEV;
174 
175 	if (pr->flags.need_hotplug_init)
176 		return 0;
177 
178 #ifdef CONFIG_CPU_FREQ
179 	acpi_processor_ppc_has_changed(pr, 0);
180 #endif
181 	acpi_processor_get_throttling_info(pr);
182 
183 	if (pr->flags.throttling)
184 		pr->flags.limit = 1;
185 
186 	if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
187 		acpi_processor_power_init(pr);
188 
189 	pr->cdev = thermal_cooling_device_register("Processor", device,
190 						   &processor_cooling_ops);
191 	if (IS_ERR(pr->cdev)) {
192 		result = PTR_ERR(pr->cdev);
193 		goto err_power_exit;
194 	}
195 
196 	dev_dbg(&device->dev, "registered as cooling_device%d\n",
197 		pr->cdev->id);
198 
199 	result = sysfs_create_link(&device->dev.kobj,
200 				   &pr->cdev->device.kobj,
201 				   "thermal_cooling");
202 	if (result) {
203 		dev_err(&device->dev,
204 			"Failed to create sysfs link 'thermal_cooling'\n");
205 		goto err_thermal_unregister;
206 	}
207 	result = sysfs_create_link(&pr->cdev->device.kobj,
208 				   &device->dev.kobj,
209 				   "device");
210 	if (result) {
211 		dev_err(&pr->cdev->device,
212 			"Failed to create sysfs link 'device'\n");
213 		goto err_remove_sysfs_thermal;
214 	}
215 
216 	status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
217 					     acpi_processor_notify, device);
218 	if (ACPI_SUCCESS(status))
219 		return 0;
220 
221 	sysfs_remove_link(&pr->cdev->device.kobj, "device");
222  err_remove_sysfs_thermal:
223 	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
224  err_thermal_unregister:
225 	thermal_cooling_device_unregister(pr->cdev);
226  err_power_exit:
227 	acpi_processor_power_exit(pr);
228 	return result;
229 }
230 
231 static int acpi_processor_start(struct device *dev)
232 {
233 	struct acpi_device *device = ACPI_COMPANION(dev);
234 
235 	if (!device)
236 		return -ENODEV;
237 
238 	return __acpi_processor_start(device);
239 }
240 
241 static int acpi_processor_stop(struct device *dev)
242 {
243 	struct acpi_device *device = ACPI_COMPANION(dev);
244 	struct acpi_processor *pr;
245 
246 	if (!device)
247 		return 0;
248 
249 	acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
250 				   acpi_processor_notify);
251 
252 	pr = acpi_driver_data(device);
253 	if (!pr)
254 		return 0;
255 
256 	acpi_processor_power_exit(pr);
257 
258 	if (pr->cdev) {
259 		sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
260 		sysfs_remove_link(&pr->cdev->device.kobj, "device");
261 		thermal_cooling_device_unregister(pr->cdev);
262 		pr->cdev = NULL;
263 	}
264 	return 0;
265 }
266 
267 /*
268  * We keep the driver loaded even when ACPI is not running.
269  * This is needed for the powernow-k8 driver, that works even without
270  * ACPI, but needs symbols from this driver
271  */
272 
273 static int __init acpi_processor_driver_init(void)
274 {
275 	int result = 0;
276 
277 	if (acpi_disabled)
278 		return 0;
279 
280 	result = driver_register(&acpi_processor_driver);
281 	if (result < 0)
282 		return result;
283 
284 	acpi_processor_syscore_init();
285 	register_hotcpu_notifier(&acpi_cpu_notifier);
286 	acpi_thermal_cpufreq_init();
287 	acpi_processor_ppc_init();
288 	acpi_processor_throttling_init();
289 	return 0;
290 }
291 
292 static void __exit acpi_processor_driver_exit(void)
293 {
294 	if (acpi_disabled)
295 		return;
296 
297 	acpi_processor_ppc_exit();
298 	acpi_thermal_cpufreq_exit();
299 	unregister_hotcpu_notifier(&acpi_cpu_notifier);
300 	acpi_processor_syscore_exit();
301 	driver_unregister(&acpi_processor_driver);
302 }
303 
304 module_init(acpi_processor_driver_init);
305 module_exit(acpi_processor_driver_exit);
306 
307 MODULE_ALIAS("processor");
308