[PATCH] video/aty/mach64_ct.c: fix bogus delay loop
[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 #include <linux/mutex.h>
37 #include <linux/freezer.h>
38
39 #include <asm/prom.h>
40
41 #include "windfarm.h"
42
43 #define VERSION "0.2"
44
45 #undef DEBUG
46
47 #ifdef DEBUG
48 #define DBG(args...)    printk(args)
49 #else
50 #define DBG(args...)    do { } while(0)
51 #endif
52
53 static LIST_HEAD(wf_controls);
54 static LIST_HEAD(wf_sensors);
55 static DEFINE_MUTEX(wf_lock);
56 static BLOCKING_NOTIFIER_HEAD(wf_client_list);
57 static int wf_client_count;
58 static unsigned int wf_overtemp;
59 static unsigned int wf_overtemp_counter;
60 struct task_struct *wf_thread;
61
62 static struct platform_device wf_platform_device = {
63         .name   = "windfarm",
64 };
65
66 /*
67  * Utilities & tick thread
68  */
69
70 static inline void wf_notify(int event, void *param)
71 {
72         blocking_notifier_call_chain(&wf_client_list, event, param);
73 }
74
75 int wf_critical_overtemp(void)
76 {
77         static char * critical_overtemp_path = "/sbin/critical_overtemp";
78         char *argv[] = { critical_overtemp_path, NULL };
79         static char *envp[] = { "HOME=/",
80                                 "TERM=linux",
81                                 "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
82                                 NULL };
83
84         return call_usermodehelper(critical_overtemp_path, argv, envp, 0);
85 }
86 EXPORT_SYMBOL_GPL(wf_critical_overtemp);
87
88 static int wf_thread_func(void *data)
89 {
90         unsigned long next, delay;
91
92         next = jiffies;
93
94         DBG("wf: thread started\n");
95
96         while(!kthread_should_stop()) {
97                 if (time_after_eq(jiffies, next)) {
98                         wf_notify(WF_EVENT_TICK, NULL);
99                         if (wf_overtemp) {
100                                 wf_overtemp_counter++;
101                                 /* 10 seconds overtemp, notify userland */
102                                 if (wf_overtemp_counter > 10)
103                                         wf_critical_overtemp();
104                                 /* 30 seconds, shutdown */
105                                 if (wf_overtemp_counter > 30) {
106                                         printk(KERN_ERR "windfarm: Overtemp "
107                                                "for more than 30"
108                                                " seconds, shutting down\n");
109                                         machine_power_off();
110                                 }
111                         }
112                         next += HZ;
113                 }
114
115                 delay = next - jiffies;
116                 if (delay <= HZ)
117                         schedule_timeout_interruptible(delay);
118
119                 /* there should be no non-suspend signal, but oh well */
120                 if (signal_pending(current) && !try_to_freeze()) {
121                         printk(KERN_WARNING "windfarm: thread got sigl !\n");
122                         break;
123                 }
124         }
125
126         DBG("wf: thread stopped\n");
127
128         return 0;
129 }
130
131 static void wf_start_thread(void)
132 {
133         wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
134         if (IS_ERR(wf_thread)) {
135                 printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
136                        PTR_ERR(wf_thread));
137                 wf_thread = NULL;
138         }
139 }
140
141
142 static void wf_stop_thread(void)
143 {
144         if (wf_thread)
145                 kthread_stop(wf_thread);
146         wf_thread = NULL;
147 }
148
149 /*
150  * Controls
151  */
152
153 static void wf_control_release(struct kref *kref)
154 {
155         struct wf_control *ct = container_of(kref, struct wf_control, ref);
156
157         DBG("wf: Deleting control %s\n", ct->name);
158
159         if (ct->ops && ct->ops->release)
160                 ct->ops->release(ct);
161         else
162                 kfree(ct);
163 }
164
165 static ssize_t wf_show_control(struct device *dev,
166                                struct device_attribute *attr, char *buf)
167 {
168         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
169         s32 val = 0;
170         int err;
171
172         err = ctrl->ops->get_value(ctrl, &val);
173         if (err < 0)
174                 return err;
175         return sprintf(buf, "%d\n", val);
176 }
177
178 /* This is really only for debugging... */
179 static ssize_t wf_store_control(struct device *dev,
180                                 struct device_attribute *attr,
181                                 const char *buf, size_t count)
182 {
183         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
184         int val;
185         int err;
186         char *endp;
187
188         val = simple_strtoul(buf, &endp, 0);
189         while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
190                 ++endp;
191         if (endp - buf < count)
192                 return -EINVAL;
193         err = ctrl->ops->set_value(ctrl, val);
194         if (err < 0)
195                 return err;
196         return count;
197 }
198
199 int wf_register_control(struct wf_control *new_ct)
200 {
201         struct wf_control *ct;
202
203         mutex_lock(&wf_lock);
204         list_for_each_entry(ct, &wf_controls, link) {
205                 if (!strcmp(ct->name, new_ct->name)) {
206                         printk(KERN_WARNING "windfarm: trying to register"
207                                " duplicate control %s\n", ct->name);
208                         mutex_unlock(&wf_lock);
209                         return -EEXIST;
210                 }
211         }
212         kref_init(&new_ct->ref);
213         list_add(&new_ct->link, &wf_controls);
214
215         new_ct->attr.attr.name = new_ct->name;
216         new_ct->attr.attr.owner = THIS_MODULE;
217         new_ct->attr.attr.mode = 0644;
218         new_ct->attr.show = wf_show_control;
219         new_ct->attr.store = wf_store_control;
220         device_create_file(&wf_platform_device.dev, &new_ct->attr);
221
222         DBG("wf: Registered control %s\n", new_ct->name);
223
224         wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
225         mutex_unlock(&wf_lock);
226
227         return 0;
228 }
229 EXPORT_SYMBOL_GPL(wf_register_control);
230
231 void wf_unregister_control(struct wf_control *ct)
232 {
233         mutex_lock(&wf_lock);
234         list_del(&ct->link);
235         mutex_unlock(&wf_lock);
236
237         DBG("wf: Unregistered control %s\n", ct->name);
238
239         kref_put(&ct->ref, wf_control_release);
240 }
241 EXPORT_SYMBOL_GPL(wf_unregister_control);
242
243 struct wf_control * wf_find_control(const char *name)
244 {
245         struct wf_control *ct;
246
247         mutex_lock(&wf_lock);
248         list_for_each_entry(ct, &wf_controls, link) {
249                 if (!strcmp(ct->name, name)) {
250                         if (wf_get_control(ct))
251                                 ct = NULL;
252                         mutex_unlock(&wf_lock);
253                         return ct;
254                 }
255         }
256         mutex_unlock(&wf_lock);
257         return NULL;
258 }
259 EXPORT_SYMBOL_GPL(wf_find_control);
260
261 int wf_get_control(struct wf_control *ct)
262 {
263         if (!try_module_get(ct->ops->owner))
264                 return -ENODEV;
265         kref_get(&ct->ref);
266         return 0;
267 }
268 EXPORT_SYMBOL_GPL(wf_get_control);
269
270 void wf_put_control(struct wf_control *ct)
271 {
272         struct module *mod = ct->ops->owner;
273         kref_put(&ct->ref, wf_control_release);
274         module_put(mod);
275 }
276 EXPORT_SYMBOL_GPL(wf_put_control);
277
278
279 /*
280  * Sensors
281  */
282
283
284 static void wf_sensor_release(struct kref *kref)
285 {
286         struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
287
288         DBG("wf: Deleting sensor %s\n", sr->name);
289
290         if (sr->ops && sr->ops->release)
291                 sr->ops->release(sr);
292         else
293                 kfree(sr);
294 }
295
296 static ssize_t wf_show_sensor(struct device *dev,
297                               struct device_attribute *attr, char *buf)
298 {
299         struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
300         s32 val = 0;
301         int err;
302
303         err = sens->ops->get_value(sens, &val);
304         if (err < 0)
305                 return err;
306         return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
307 }
308
309 int wf_register_sensor(struct wf_sensor *new_sr)
310 {
311         struct wf_sensor *sr;
312
313         mutex_lock(&wf_lock);
314         list_for_each_entry(sr, &wf_sensors, link) {
315                 if (!strcmp(sr->name, new_sr->name)) {
316                         printk(KERN_WARNING "windfarm: trying to register"
317                                " duplicate sensor %s\n", sr->name);
318                         mutex_unlock(&wf_lock);
319                         return -EEXIST;
320                 }
321         }
322         kref_init(&new_sr->ref);
323         list_add(&new_sr->link, &wf_sensors);
324
325         new_sr->attr.attr.name = new_sr->name;
326         new_sr->attr.attr.owner = THIS_MODULE;
327         new_sr->attr.attr.mode = 0444;
328         new_sr->attr.show = wf_show_sensor;
329         new_sr->attr.store = NULL;
330         device_create_file(&wf_platform_device.dev, &new_sr->attr);
331
332         DBG("wf: Registered sensor %s\n", new_sr->name);
333
334         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
335         mutex_unlock(&wf_lock);
336
337         return 0;
338 }
339 EXPORT_SYMBOL_GPL(wf_register_sensor);
340
341 void wf_unregister_sensor(struct wf_sensor *sr)
342 {
343         mutex_lock(&wf_lock);
344         list_del(&sr->link);
345         mutex_unlock(&wf_lock);
346
347         DBG("wf: Unregistered sensor %s\n", sr->name);
348
349         wf_put_sensor(sr);
350 }
351 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
352
353 struct wf_sensor * wf_find_sensor(const char *name)
354 {
355         struct wf_sensor *sr;
356
357         mutex_lock(&wf_lock);
358         list_for_each_entry(sr, &wf_sensors, link) {
359                 if (!strcmp(sr->name, name)) {
360                         if (wf_get_sensor(sr))
361                                 sr = NULL;
362                         mutex_unlock(&wf_lock);
363                         return sr;
364                 }
365         }
366         mutex_unlock(&wf_lock);
367         return NULL;
368 }
369 EXPORT_SYMBOL_GPL(wf_find_sensor);
370
371 int wf_get_sensor(struct wf_sensor *sr)
372 {
373         if (!try_module_get(sr->ops->owner))
374                 return -ENODEV;
375         kref_get(&sr->ref);
376         return 0;
377 }
378 EXPORT_SYMBOL_GPL(wf_get_sensor);
379
380 void wf_put_sensor(struct wf_sensor *sr)
381 {
382         struct module *mod = sr->ops->owner;
383         kref_put(&sr->ref, wf_sensor_release);
384         module_put(mod);
385 }
386 EXPORT_SYMBOL_GPL(wf_put_sensor);
387
388
389 /*
390  * Client & notification
391  */
392
393 int wf_register_client(struct notifier_block *nb)
394 {
395         int rc;
396         struct wf_control *ct;
397         struct wf_sensor *sr;
398
399         mutex_lock(&wf_lock);
400         rc = blocking_notifier_chain_register(&wf_client_list, nb);
401         if (rc != 0)
402                 goto bail;
403         wf_client_count++;
404         list_for_each_entry(ct, &wf_controls, link)
405                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
406         list_for_each_entry(sr, &wf_sensors, link)
407                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
408         if (wf_client_count == 1)
409                 wf_start_thread();
410  bail:
411         mutex_unlock(&wf_lock);
412         return rc;
413 }
414 EXPORT_SYMBOL_GPL(wf_register_client);
415
416 int wf_unregister_client(struct notifier_block *nb)
417 {
418         mutex_lock(&wf_lock);
419         blocking_notifier_chain_unregister(&wf_client_list, nb);
420         wf_client_count++;
421         if (wf_client_count == 0)
422                 wf_stop_thread();
423         mutex_unlock(&wf_lock);
424
425         return 0;
426 }
427 EXPORT_SYMBOL_GPL(wf_unregister_client);
428
429 void wf_set_overtemp(void)
430 {
431         mutex_lock(&wf_lock);
432         wf_overtemp++;
433         if (wf_overtemp == 1) {
434                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
435                 wf_overtemp_counter = 0;
436                 wf_notify(WF_EVENT_OVERTEMP, NULL);
437         }
438         mutex_unlock(&wf_lock);
439 }
440 EXPORT_SYMBOL_GPL(wf_set_overtemp);
441
442 void wf_clear_overtemp(void)
443 {
444         mutex_lock(&wf_lock);
445         WARN_ON(wf_overtemp == 0);
446         if (wf_overtemp == 0) {
447                 mutex_unlock(&wf_lock);
448                 return;
449         }
450         wf_overtemp--;
451         if (wf_overtemp == 0) {
452                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
453                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
454         }
455         mutex_unlock(&wf_lock);
456 }
457 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
458
459 int wf_is_overtemp(void)
460 {
461         return (wf_overtemp != 0);
462 }
463 EXPORT_SYMBOL_GPL(wf_is_overtemp);
464
465 static int __init windfarm_core_init(void)
466 {
467         DBG("wf: core loaded\n");
468
469         /* Don't register on old machines that use therm_pm72 for now */
470         if (machine_is_compatible("PowerMac7,2") ||
471             machine_is_compatible("PowerMac7,3") ||
472             machine_is_compatible("RackMac3,1"))
473                 return -ENODEV;
474         platform_device_register(&wf_platform_device);
475         return 0;
476 }
477
478 static void __exit windfarm_core_exit(void)
479 {
480         BUG_ON(wf_client_count != 0);
481
482         DBG("wf: core unloaded\n");
483
484         platform_device_unregister(&wf_platform_device);
485 }
486
487
488 module_init(windfarm_core_init);
489 module_exit(windfarm_core_exit);
490
491 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
492 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
493 MODULE_LICENSE("GPL");
494