Merge ../linux-2.6
[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
38 #include <asm/prom.h>
39
40 #include "windfarm.h"
41
42 #define VERSION "0.2"
43
44 #undef DEBUG
45
46 #ifdef DEBUG
47 #define DBG(args...)    printk(args)
48 #else
49 #define DBG(args...)    do { } while(0)
50 #endif
51
52 static LIST_HEAD(wf_controls);
53 static LIST_HEAD(wf_sensors);
54 static DEFINE_MUTEX(wf_lock);
55 static struct notifier_block *wf_client_list;
56 static int wf_client_count;
57 static unsigned int wf_overtemp;
58 static unsigned int wf_overtemp_counter;
59 struct task_struct *wf_thread;
60
61 static struct platform_device wf_platform_device = {
62         .name   = "windfarm",
63 };
64
65 /*
66  * Utilities & tick thread
67  */
68
69 static inline void wf_notify(int event, void *param)
70 {
71         notifier_call_chain(&wf_client_list, event, param);
72 }
73
74 int wf_critical_overtemp(void)
75 {
76         static char * critical_overtemp_path = "/sbin/critical_overtemp";
77         char *argv[] = { critical_overtemp_path, NULL };
78         static char *envp[] = { "HOME=/",
79                                 "TERM=linux",
80                                 "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
81                                 NULL };
82
83         return call_usermodehelper(critical_overtemp_path, argv, envp, 0);
84 }
85 EXPORT_SYMBOL_GPL(wf_critical_overtemp);
86
87 static int wf_thread_func(void *data)
88 {
89         unsigned long next, delay;
90
91         next = jiffies;
92
93         DBG("wf: thread started\n");
94
95         while(!kthread_should_stop()) {
96                 try_to_freeze();
97
98                 if (time_after_eq(jiffies, next)) {
99                         wf_notify(WF_EVENT_TICK, NULL);
100                         if (wf_overtemp) {
101                                 wf_overtemp_counter++;
102                                 /* 10 seconds overtemp, notify userland */
103                                 if (wf_overtemp_counter > 10)
104                                         wf_critical_overtemp();
105                                 /* 30 seconds, shutdown */
106                                 if (wf_overtemp_counter > 30) {
107                                         printk(KERN_ERR "windfarm: Overtemp "
108                                                "for more than 30"
109                                                " seconds, shutting down\n");
110                                         machine_power_off();
111                                 }
112                         }
113                         next += HZ;
114                 }
115
116                 delay = next - jiffies;
117                 if (delay <= HZ)
118                         schedule_timeout_interruptible(delay);
119
120                 /* there should be no signal, but oh well */
121                 if (signal_pending(current)) {
122                         printk(KERN_WARNING "windfarm: thread got sigl !\n");
123                         break;
124                 }
125         }
126
127         DBG("wf: thread stopped\n");
128
129         return 0;
130 }
131
132 static void wf_start_thread(void)
133 {
134         wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
135         if (IS_ERR(wf_thread)) {
136                 printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
137                        PTR_ERR(wf_thread));
138                 wf_thread = NULL;
139         }
140 }
141
142
143 static void wf_stop_thread(void)
144 {
145         if (wf_thread)
146                 kthread_stop(wf_thread);
147         wf_thread = NULL;
148 }
149
150 /*
151  * Controls
152  */
153
154 static void wf_control_release(struct kref *kref)
155 {
156         struct wf_control *ct = container_of(kref, struct wf_control, ref);
157
158         DBG("wf: Deleting control %s\n", ct->name);
159
160         if (ct->ops && ct->ops->release)
161                 ct->ops->release(ct);
162         else
163                 kfree(ct);
164 }
165
166 static ssize_t wf_show_control(struct device *dev,
167                                struct device_attribute *attr, char *buf)
168 {
169         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
170         s32 val = 0;
171         int err;
172
173         err = ctrl->ops->get_value(ctrl, &val);
174         if (err < 0)
175                 return err;
176         return sprintf(buf, "%d\n", val);
177 }
178
179 /* This is really only for debugging... */
180 static ssize_t wf_store_control(struct device *dev,
181                                 struct device_attribute *attr,
182                                 const char *buf, size_t count)
183 {
184         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
185         int val;
186         int err;
187         char *endp;
188
189         val = simple_strtoul(buf, &endp, 0);
190         while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
191                 ++endp;
192         if (endp - buf < count)
193                 return -EINVAL;
194         err = ctrl->ops->set_value(ctrl, val);
195         if (err < 0)
196                 return err;
197         return count;
198 }
199
200 int wf_register_control(struct wf_control *new_ct)
201 {
202         struct wf_control *ct;
203
204         mutex_lock(&wf_lock);
205         list_for_each_entry(ct, &wf_controls, link) {
206                 if (!strcmp(ct->name, new_ct->name)) {
207                         printk(KERN_WARNING "windfarm: trying to register"
208                                " duplicate control %s\n", ct->name);
209                         mutex_unlock(&wf_lock);
210                         return -EEXIST;
211                 }
212         }
213         kref_init(&new_ct->ref);
214         list_add(&new_ct->link, &wf_controls);
215
216         new_ct->attr.attr.name = new_ct->name;
217         new_ct->attr.attr.owner = THIS_MODULE;
218         new_ct->attr.attr.mode = 0644;
219         new_ct->attr.show = wf_show_control;
220         new_ct->attr.store = wf_store_control;
221         device_create_file(&wf_platform_device.dev, &new_ct->attr);
222
223         DBG("wf: Registered control %s\n", new_ct->name);
224
225         wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
226         mutex_unlock(&wf_lock);
227
228         return 0;
229 }
230 EXPORT_SYMBOL_GPL(wf_register_control);
231
232 void wf_unregister_control(struct wf_control *ct)
233 {
234         mutex_lock(&wf_lock);
235         list_del(&ct->link);
236         mutex_unlock(&wf_lock);
237
238         DBG("wf: Unregistered control %s\n", ct->name);
239
240         kref_put(&ct->ref, wf_control_release);
241 }
242 EXPORT_SYMBOL_GPL(wf_unregister_control);
243
244 struct wf_control * wf_find_control(const char *name)
245 {
246         struct wf_control *ct;
247
248         mutex_lock(&wf_lock);
249         list_for_each_entry(ct, &wf_controls, link) {
250                 if (!strcmp(ct->name, name)) {
251                         if (wf_get_control(ct))
252                                 ct = NULL;
253                         mutex_unlock(&wf_lock);
254                         return ct;
255                 }
256         }
257         mutex_unlock(&wf_lock);
258         return NULL;
259 }
260 EXPORT_SYMBOL_GPL(wf_find_control);
261
262 int wf_get_control(struct wf_control *ct)
263 {
264         if (!try_module_get(ct->ops->owner))
265                 return -ENODEV;
266         kref_get(&ct->ref);
267         return 0;
268 }
269 EXPORT_SYMBOL_GPL(wf_get_control);
270
271 void wf_put_control(struct wf_control *ct)
272 {
273         struct module *mod = ct->ops->owner;
274         kref_put(&ct->ref, wf_control_release);
275         module_put(mod);
276 }
277 EXPORT_SYMBOL_GPL(wf_put_control);
278
279
280 /*
281  * Sensors
282  */
283
284
285 static void wf_sensor_release(struct kref *kref)
286 {
287         struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
288
289         DBG("wf: Deleting sensor %s\n", sr->name);
290
291         if (sr->ops && sr->ops->release)
292                 sr->ops->release(sr);
293         else
294                 kfree(sr);
295 }
296
297 static ssize_t wf_show_sensor(struct device *dev,
298                               struct device_attribute *attr, char *buf)
299 {
300         struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
301         s32 val = 0;
302         int err;
303
304         err = sens->ops->get_value(sens, &val);
305         if (err < 0)
306                 return err;
307         return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
308 }
309
310 int wf_register_sensor(struct wf_sensor *new_sr)
311 {
312         struct wf_sensor *sr;
313
314         mutex_lock(&wf_lock);
315         list_for_each_entry(sr, &wf_sensors, link) {
316                 if (!strcmp(sr->name, new_sr->name)) {
317                         printk(KERN_WARNING "windfarm: trying to register"
318                                " duplicate sensor %s\n", sr->name);
319                         mutex_unlock(&wf_lock);
320                         return -EEXIST;
321                 }
322         }
323         kref_init(&new_sr->ref);
324         list_add(&new_sr->link, &wf_sensors);
325
326         new_sr->attr.attr.name = new_sr->name;
327         new_sr->attr.attr.owner = THIS_MODULE;
328         new_sr->attr.attr.mode = 0444;
329         new_sr->attr.show = wf_show_sensor;
330         new_sr->attr.store = NULL;
331         device_create_file(&wf_platform_device.dev, &new_sr->attr);
332
333         DBG("wf: Registered sensor %s\n", new_sr->name);
334
335         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
336         mutex_unlock(&wf_lock);
337
338         return 0;
339 }
340 EXPORT_SYMBOL_GPL(wf_register_sensor);
341
342 void wf_unregister_sensor(struct wf_sensor *sr)
343 {
344         mutex_lock(&wf_lock);
345         list_del(&sr->link);
346         mutex_unlock(&wf_lock);
347
348         DBG("wf: Unregistered sensor %s\n", sr->name);
349
350         wf_put_sensor(sr);
351 }
352 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
353
354 struct wf_sensor * wf_find_sensor(const char *name)
355 {
356         struct wf_sensor *sr;
357
358         mutex_lock(&wf_lock);
359         list_for_each_entry(sr, &wf_sensors, link) {
360                 if (!strcmp(sr->name, name)) {
361                         if (wf_get_sensor(sr))
362                                 sr = NULL;
363                         mutex_unlock(&wf_lock);
364                         return sr;
365                 }
366         }
367         mutex_unlock(&wf_lock);
368         return NULL;
369 }
370 EXPORT_SYMBOL_GPL(wf_find_sensor);
371
372 int wf_get_sensor(struct wf_sensor *sr)
373 {
374         if (!try_module_get(sr->ops->owner))
375                 return -ENODEV;
376         kref_get(&sr->ref);
377         return 0;
378 }
379 EXPORT_SYMBOL_GPL(wf_get_sensor);
380
381 void wf_put_sensor(struct wf_sensor *sr)
382 {
383         struct module *mod = sr->ops->owner;
384         kref_put(&sr->ref, wf_sensor_release);
385         module_put(mod);
386 }
387 EXPORT_SYMBOL_GPL(wf_put_sensor);
388
389
390 /*
391  * Client & notification
392  */
393
394 int wf_register_client(struct notifier_block *nb)
395 {
396         int rc;
397         struct wf_control *ct;
398         struct wf_sensor *sr;
399
400         mutex_lock(&wf_lock);
401         rc = notifier_chain_register(&wf_client_list, nb);
402         if (rc != 0)
403                 goto bail;
404         wf_client_count++;
405         list_for_each_entry(ct, &wf_controls, link)
406                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
407         list_for_each_entry(sr, &wf_sensors, link)
408                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
409         if (wf_client_count == 1)
410                 wf_start_thread();
411  bail:
412         mutex_unlock(&wf_lock);
413         return rc;
414 }
415 EXPORT_SYMBOL_GPL(wf_register_client);
416
417 int wf_unregister_client(struct notifier_block *nb)
418 {
419         mutex_lock(&wf_lock);
420         notifier_chain_unregister(&wf_client_list, nb);
421         wf_client_count++;
422         if (wf_client_count == 0)
423                 wf_stop_thread();
424         mutex_unlock(&wf_lock);
425
426         return 0;
427 }
428 EXPORT_SYMBOL_GPL(wf_unregister_client);
429
430 void wf_set_overtemp(void)
431 {
432         mutex_lock(&wf_lock);
433         wf_overtemp++;
434         if (wf_overtemp == 1) {
435                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
436                 wf_overtemp_counter = 0;
437                 wf_notify(WF_EVENT_OVERTEMP, NULL);
438         }
439         mutex_unlock(&wf_lock);
440 }
441 EXPORT_SYMBOL_GPL(wf_set_overtemp);
442
443 void wf_clear_overtemp(void)
444 {
445         mutex_lock(&wf_lock);
446         WARN_ON(wf_overtemp == 0);
447         if (wf_overtemp == 0) {
448                 mutex_unlock(&wf_lock);
449                 return;
450         }
451         wf_overtemp--;
452         if (wf_overtemp == 0) {
453                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
454                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
455         }
456         mutex_unlock(&wf_lock);
457 }
458 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
459
460 int wf_is_overtemp(void)
461 {
462         return (wf_overtemp != 0);
463 }
464 EXPORT_SYMBOL_GPL(wf_is_overtemp);
465
466 static int __init windfarm_core_init(void)
467 {
468         DBG("wf: core loaded\n");
469
470         /* Don't register on old machines that use therm_pm72 for now */
471         if (machine_is_compatible("PowerMac7,2") ||
472             machine_is_compatible("PowerMac7,3") ||
473             machine_is_compatible("RackMac3,1"))
474                 return -ENODEV;
475         platform_device_register(&wf_platform_device);
476         return 0;
477 }
478
479 static void __exit windfarm_core_exit(void)
480 {
481         BUG_ON(wf_client_count != 0);
482
483         DBG("wf: core unloaded\n");
484
485         platform_device_unregister(&wf_platform_device);
486 }
487
488
489 module_init(windfarm_core_init);
490 module_exit(windfarm_core_exit);
491
492 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
493 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
494 MODULE_LICENSE("GPL");
495