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Linux/drivers/acpi/processor_driver.c

  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 

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