Merge branch 'master'
[linux-2.6] / drivers / macintosh / windfarm_core.c
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