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75722d39 BH |
1 | /* |
2 | * Windfarm PowerMac thermal control. Core | |
3 | * | |
4 | * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp. | |
5 | * <benh@kernel.crashing.org> | |
6 | * | |
7 | * Released under the term of the GNU GPL v2. | |
8 | * | |
9 | * This core code tracks the list of sensors & controls, register | |
10 | * clients, and holds the kernel thread used for control. | |
11 | * | |
12 | * TODO: | |
13 | * | |
14 | * Add some information about sensor/control type and data format to | |
15 | * sensors/controls, and have the sysfs attribute stuff be moved | |
16 | * generically here instead of hard coded in the platform specific | |
17 | * driver as it us currently | |
18 | * | |
19 | * This however requires solving some annoying lifetime issues with | |
20 | * sysfs which doesn't seem to have lifetime rules for struct attribute, | |
21 | * I may have to create full features kobjects for every sensor/control | |
22 | * instead which is a bit of an overkill imho | |
23 | */ | |
24 | ||
25 | #include <linux/types.h> | |
26 | #include <linux/errno.h> | |
27 | #include <linux/kernel.h> | |
28 | #include <linux/init.h> | |
29 | #include <linux/spinlock.h> | |
30 | #include <linux/smp_lock.h> | |
31 | #include <linux/kthread.h> | |
32 | #include <linux/jiffies.h> | |
33 | #include <linux/reboot.h> | |
34 | #include <linux/device.h> | |
35 | #include <linux/platform_device.h> | |
36 | ||
37 | #include "windfarm.h" | |
38 | ||
39 | #define VERSION "0.2" | |
40 | ||
41 | #undef DEBUG | |
42 | ||
43 | #ifdef DEBUG | |
44 | #define DBG(args...) printk(args) | |
45 | #else | |
46 | #define DBG(args...) do { } while(0) | |
47 | #endif | |
48 | ||
49 | static LIST_HEAD(wf_controls); | |
50 | static LIST_HEAD(wf_sensors); | |
51 | static DECLARE_MUTEX(wf_lock); | |
52 | static struct notifier_block *wf_client_list; | |
53 | static int wf_client_count; | |
54 | static unsigned int wf_overtemp; | |
55 | static unsigned int wf_overtemp_counter; | |
56 | struct task_struct *wf_thread; | |
57 | ||
58 | /* | |
59 | * Utilities & tick thread | |
60 | */ | |
61 | ||
62 | static inline void wf_notify(int event, void *param) | |
63 | { | |
64 | notifier_call_chain(&wf_client_list, event, param); | |
65 | } | |
66 | ||
67 | int wf_critical_overtemp(void) | |
68 | { | |
69 | static char * critical_overtemp_path = "/sbin/critical_overtemp"; | |
70 | char *argv[] = { critical_overtemp_path, NULL }; | |
71 | static char *envp[] = { "HOME=/", | |
72 | "TERM=linux", | |
73 | "PATH=/sbin:/usr/sbin:/bin:/usr/bin", | |
74 | NULL }; | |
75 | ||
76 | return call_usermodehelper(critical_overtemp_path, argv, envp, 0); | |
77 | } | |
78 | EXPORT_SYMBOL_GPL(wf_critical_overtemp); | |
79 | ||
80 | static int wf_thread_func(void *data) | |
81 | { | |
82 | unsigned long next, delay; | |
83 | ||
84 | next = jiffies; | |
85 | ||
86 | DBG("wf: thread started\n"); | |
87 | ||
88 | while(!kthread_should_stop()) { | |
89 | try_to_freeze(); | |
90 | ||
91 | if (time_after_eq(jiffies, next)) { | |
92 | wf_notify(WF_EVENT_TICK, NULL); | |
93 | if (wf_overtemp) { | |
94 | wf_overtemp_counter++; | |
95 | /* 10 seconds overtemp, notify userland */ | |
96 | if (wf_overtemp_counter > 10) | |
97 | wf_critical_overtemp(); | |
98 | /* 30 seconds, shutdown */ | |
99 | if (wf_overtemp_counter > 30) { | |
100 | printk(KERN_ERR "windfarm: Overtemp " | |
101 | "for more than 30" | |
102 | " seconds, shutting down\n"); | |
103 | machine_power_off(); | |
104 | } | |
105 | } | |
106 | next += HZ; | |
107 | } | |
108 | ||
109 | delay = next - jiffies; | |
110 | if (delay <= HZ) | |
111 | schedule_timeout_interruptible(delay); | |
112 | ||
113 | /* there should be no signal, but oh well */ | |
114 | if (signal_pending(current)) { | |
115 | printk(KERN_WARNING "windfarm: thread got sigl !\n"); | |
116 | break; | |
117 | } | |
118 | } | |
119 | ||
120 | DBG("wf: thread stopped\n"); | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
125 | static void wf_start_thread(void) | |
126 | { | |
127 | wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm"); | |
128 | if (IS_ERR(wf_thread)) { | |
129 | printk(KERN_ERR "windfarm: failed to create thread,err %ld\n", | |
130 | PTR_ERR(wf_thread)); | |
131 | wf_thread = NULL; | |
132 | } | |
133 | } | |
134 | ||
135 | ||
136 | static void wf_stop_thread(void) | |
137 | { | |
138 | if (wf_thread) | |
139 | kthread_stop(wf_thread); | |
140 | wf_thread = NULL; | |
141 | } | |
142 | ||
143 | /* | |
144 | * Controls | |
145 | */ | |
146 | ||
147 | static void wf_control_release(struct kref *kref) | |
148 | { | |
149 | struct wf_control *ct = container_of(kref, struct wf_control, ref); | |
150 | ||
151 | DBG("wf: Deleting control %s\n", ct->name); | |
152 | ||
153 | if (ct->ops && ct->ops->release) | |
154 | ct->ops->release(ct); | |
155 | else | |
156 | kfree(ct); | |
157 | } | |
158 | ||
159 | int wf_register_control(struct wf_control *new_ct) | |
160 | { | |
161 | struct wf_control *ct; | |
162 | ||
163 | down(&wf_lock); | |
164 | list_for_each_entry(ct, &wf_controls, link) { | |
165 | if (!strcmp(ct->name, new_ct->name)) { | |
166 | printk(KERN_WARNING "windfarm: trying to register" | |
167 | " duplicate control %s\n", ct->name); | |
168 | up(&wf_lock); | |
169 | return -EEXIST; | |
170 | } | |
171 | } | |
172 | kref_init(&new_ct->ref); | |
173 | list_add(&new_ct->link, &wf_controls); | |
174 | ||
175 | DBG("wf: Registered control %s\n", new_ct->name); | |
176 | ||
177 | wf_notify(WF_EVENT_NEW_CONTROL, new_ct); | |
178 | up(&wf_lock); | |
179 | ||
180 | return 0; | |
181 | } | |
182 | EXPORT_SYMBOL_GPL(wf_register_control); | |
183 | ||
184 | void wf_unregister_control(struct wf_control *ct) | |
185 | { | |
186 | down(&wf_lock); | |
187 | list_del(&ct->link); | |
188 | up(&wf_lock); | |
189 | ||
190 | DBG("wf: Unregistered control %s\n", ct->name); | |
191 | ||
192 | kref_put(&ct->ref, wf_control_release); | |
193 | } | |
194 | EXPORT_SYMBOL_GPL(wf_unregister_control); | |
195 | ||
196 | struct wf_control * wf_find_control(const char *name) | |
197 | { | |
198 | struct wf_control *ct; | |
199 | ||
200 | down(&wf_lock); | |
201 | list_for_each_entry(ct, &wf_controls, link) { | |
202 | if (!strcmp(ct->name, name)) { | |
203 | if (wf_get_control(ct)) | |
204 | ct = NULL; | |
205 | up(&wf_lock); | |
206 | return ct; | |
207 | } | |
208 | } | |
209 | up(&wf_lock); | |
210 | return NULL; | |
211 | } | |
212 | EXPORT_SYMBOL_GPL(wf_find_control); | |
213 | ||
214 | int wf_get_control(struct wf_control *ct) | |
215 | { | |
216 | if (!try_module_get(ct->ops->owner)) | |
217 | return -ENODEV; | |
218 | kref_get(&ct->ref); | |
219 | return 0; | |
220 | } | |
221 | EXPORT_SYMBOL_GPL(wf_get_control); | |
222 | ||
223 | void wf_put_control(struct wf_control *ct) | |
224 | { | |
225 | struct module *mod = ct->ops->owner; | |
226 | kref_put(&ct->ref, wf_control_release); | |
227 | module_put(mod); | |
228 | } | |
229 | EXPORT_SYMBOL_GPL(wf_put_control); | |
230 | ||
231 | ||
232 | /* | |
233 | * Sensors | |
234 | */ | |
235 | ||
236 | ||
237 | static void wf_sensor_release(struct kref *kref) | |
238 | { | |
239 | struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref); | |
240 | ||
241 | DBG("wf: Deleting sensor %s\n", sr->name); | |
242 | ||
243 | if (sr->ops && sr->ops->release) | |
244 | sr->ops->release(sr); | |
245 | else | |
246 | kfree(sr); | |
247 | } | |
248 | ||
249 | int wf_register_sensor(struct wf_sensor *new_sr) | |
250 | { | |
251 | struct wf_sensor *sr; | |
252 | ||
253 | down(&wf_lock); | |
254 | list_for_each_entry(sr, &wf_sensors, link) { | |
255 | if (!strcmp(sr->name, new_sr->name)) { | |
256 | printk(KERN_WARNING "windfarm: trying to register" | |
257 | " duplicate sensor %s\n", sr->name); | |
258 | up(&wf_lock); | |
259 | return -EEXIST; | |
260 | } | |
261 | } | |
262 | kref_init(&new_sr->ref); | |
263 | list_add(&new_sr->link, &wf_sensors); | |
264 | ||
265 | DBG("wf: Registered sensor %s\n", new_sr->name); | |
266 | ||
267 | wf_notify(WF_EVENT_NEW_SENSOR, new_sr); | |
268 | up(&wf_lock); | |
269 | ||
270 | return 0; | |
271 | } | |
272 | EXPORT_SYMBOL_GPL(wf_register_sensor); | |
273 | ||
274 | void wf_unregister_sensor(struct wf_sensor *sr) | |
275 | { | |
276 | down(&wf_lock); | |
277 | list_del(&sr->link); | |
278 | up(&wf_lock); | |
279 | ||
280 | DBG("wf: Unregistered sensor %s\n", sr->name); | |
281 | ||
282 | wf_put_sensor(sr); | |
283 | } | |
284 | EXPORT_SYMBOL_GPL(wf_unregister_sensor); | |
285 | ||
286 | struct wf_sensor * wf_find_sensor(const char *name) | |
287 | { | |
288 | struct wf_sensor *sr; | |
289 | ||
290 | down(&wf_lock); | |
291 | list_for_each_entry(sr, &wf_sensors, link) { | |
292 | if (!strcmp(sr->name, name)) { | |
293 | if (wf_get_sensor(sr)) | |
294 | sr = NULL; | |
295 | up(&wf_lock); | |
296 | return sr; | |
297 | } | |
298 | } | |
299 | up(&wf_lock); | |
300 | return NULL; | |
301 | } | |
302 | EXPORT_SYMBOL_GPL(wf_find_sensor); | |
303 | ||
304 | int wf_get_sensor(struct wf_sensor *sr) | |
305 | { | |
306 | if (!try_module_get(sr->ops->owner)) | |
307 | return -ENODEV; | |
308 | kref_get(&sr->ref); | |
309 | return 0; | |
310 | } | |
311 | EXPORT_SYMBOL_GPL(wf_get_sensor); | |
312 | ||
313 | void wf_put_sensor(struct wf_sensor *sr) | |
314 | { | |
315 | struct module *mod = sr->ops->owner; | |
316 | kref_put(&sr->ref, wf_sensor_release); | |
317 | module_put(mod); | |
318 | } | |
319 | EXPORT_SYMBOL_GPL(wf_put_sensor); | |
320 | ||
321 | ||
322 | /* | |
323 | * Client & notification | |
324 | */ | |
325 | ||
326 | int wf_register_client(struct notifier_block *nb) | |
327 | { | |
328 | int rc; | |
329 | struct wf_control *ct; | |
330 | struct wf_sensor *sr; | |
331 | ||
332 | down(&wf_lock); | |
333 | rc = notifier_chain_register(&wf_client_list, nb); | |
334 | if (rc != 0) | |
335 | goto bail; | |
336 | wf_client_count++; | |
337 | list_for_each_entry(ct, &wf_controls, link) | |
338 | wf_notify(WF_EVENT_NEW_CONTROL, ct); | |
339 | list_for_each_entry(sr, &wf_sensors, link) | |
340 | wf_notify(WF_EVENT_NEW_SENSOR, sr); | |
341 | if (wf_client_count == 1) | |
342 | wf_start_thread(); | |
343 | bail: | |
344 | up(&wf_lock); | |
345 | return rc; | |
346 | } | |
347 | EXPORT_SYMBOL_GPL(wf_register_client); | |
348 | ||
349 | int wf_unregister_client(struct notifier_block *nb) | |
350 | { | |
351 | down(&wf_lock); | |
352 | notifier_chain_unregister(&wf_client_list, nb); | |
353 | wf_client_count++; | |
354 | if (wf_client_count == 0) | |
355 | wf_stop_thread(); | |
356 | up(&wf_lock); | |
357 | ||
358 | return 0; | |
359 | } | |
360 | EXPORT_SYMBOL_GPL(wf_unregister_client); | |
361 | ||
362 | void wf_set_overtemp(void) | |
363 | { | |
364 | down(&wf_lock); | |
365 | wf_overtemp++; | |
366 | if (wf_overtemp == 1) { | |
367 | printk(KERN_WARNING "windfarm: Overtemp condition detected !\n"); | |
368 | wf_overtemp_counter = 0; | |
369 | wf_notify(WF_EVENT_OVERTEMP, NULL); | |
370 | } | |
371 | up(&wf_lock); | |
372 | } | |
373 | EXPORT_SYMBOL_GPL(wf_set_overtemp); | |
374 | ||
375 | void wf_clear_overtemp(void) | |
376 | { | |
377 | down(&wf_lock); | |
378 | WARN_ON(wf_overtemp == 0); | |
379 | if (wf_overtemp == 0) { | |
380 | up(&wf_lock); | |
381 | return; | |
382 | } | |
383 | wf_overtemp--; | |
384 | if (wf_overtemp == 0) { | |
385 | printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n"); | |
386 | wf_notify(WF_EVENT_NORMALTEMP, NULL); | |
387 | } | |
388 | up(&wf_lock); | |
389 | } | |
390 | EXPORT_SYMBOL_GPL(wf_clear_overtemp); | |
391 | ||
392 | int wf_is_overtemp(void) | |
393 | { | |
394 | return (wf_overtemp != 0); | |
395 | } | |
396 | EXPORT_SYMBOL_GPL(wf_is_overtemp); | |
397 | ||
398 | static struct platform_device wf_platform_device = { | |
399 | .name = "windfarm", | |
400 | }; | |
401 | ||
402 | static int __init windfarm_core_init(void) | |
403 | { | |
404 | DBG("wf: core loaded\n"); | |
405 | ||
406 | platform_device_register(&wf_platform_device); | |
407 | return 0; | |
408 | } | |
409 | ||
410 | static void __exit windfarm_core_exit(void) | |
411 | { | |
412 | BUG_ON(wf_client_count != 0); | |
413 | ||
414 | DBG("wf: core unloaded\n"); | |
415 | ||
416 | platform_device_unregister(&wf_platform_device); | |
417 | } | |
418 | ||
419 | ||
420 | module_init(windfarm_core_init); | |
421 | module_exit(windfarm_core_exit); | |
422 | ||
423 | MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>"); | |
424 | MODULE_DESCRIPTION("Core component of PowerMac thermal control"); | |
425 | MODULE_LICENSE("GPL"); | |
426 |