Merge branch 'topic/hda' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie...
[linux-2.6-microblaze.git] / 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/slab.h>
29 #include <linux/init.h>
30 #include <linux/spinlock.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 static int wf_critical_overtemp(void)
76 {
77         static char const critical_overtemp_path[] = "/sbin/critical_overtemp";
78         char *argv[] = { (char *)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,
85                                    argv, envp, UMH_WAIT_EXEC);
86 }
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         set_freezable();
97         while (!kthread_should_stop()) {
98                 try_to_freeze();
99
100                 if (time_after_eq(jiffies, next)) {
101                         wf_notify(WF_EVENT_TICK, NULL);
102                         if (wf_overtemp) {
103                                 wf_overtemp_counter++;
104                                 /* 10 seconds overtemp, notify userland */
105                                 if (wf_overtemp_counter > 10)
106                                         wf_critical_overtemp();
107                                 /* 30 seconds, shutdown */
108                                 if (wf_overtemp_counter > 30) {
109                                         printk(KERN_ERR "windfarm: Overtemp "
110                                                "for more than 30"
111                                                " seconds, shutting down\n");
112                                         machine_power_off();
113                                 }
114                         }
115                         next += HZ;
116                 }
117
118                 delay = next - jiffies;
119                 if (delay <= HZ)
120                         schedule_timeout_interruptible(delay);
121         }
122
123         DBG("wf: thread stopped\n");
124
125         return 0;
126 }
127
128 static void wf_start_thread(void)
129 {
130         wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
131         if (IS_ERR(wf_thread)) {
132                 printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
133                        PTR_ERR(wf_thread));
134                 wf_thread = NULL;
135         }
136 }
137
138
139 static void wf_stop_thread(void)
140 {
141         if (wf_thread)
142                 kthread_stop(wf_thread);
143         wf_thread = NULL;
144 }
145
146 /*
147  * Controls
148  */
149
150 static void wf_control_release(struct kref *kref)
151 {
152         struct wf_control *ct = container_of(kref, struct wf_control, ref);
153
154         DBG("wf: Deleting control %s\n", ct->name);
155
156         if (ct->ops && ct->ops->release)
157                 ct->ops->release(ct);
158         else
159                 kfree(ct);
160 }
161
162 static ssize_t wf_show_control(struct device *dev,
163                                struct device_attribute *attr, char *buf)
164 {
165         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
166         const char *typestr;
167         s32 val = 0;
168         int err;
169
170         err = ctrl->ops->get_value(ctrl, &val);
171         if (err < 0) {
172                 if (err == -EFAULT)
173                         return sprintf(buf, "<HW FAULT>\n");
174                 return err;
175         }
176         switch(ctrl->type) {
177         case WF_CONTROL_RPM_FAN:
178                 typestr = " RPM";
179                 break;
180         case WF_CONTROL_PWM_FAN:
181                 typestr = " %";
182                 break;
183         default:
184                 typestr = "";
185         }
186         return sprintf(buf, "%d%s\n", val, typestr);
187 }
188
189 /* This is really only for debugging... */
190 static ssize_t wf_store_control(struct device *dev,
191                                 struct device_attribute *attr,
192                                 const char *buf, size_t count)
193 {
194         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
195         int val;
196         int err;
197         char *endp;
198
199         val = simple_strtoul(buf, &endp, 0);
200         while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
201                 ++endp;
202         if (endp - buf < count)
203                 return -EINVAL;
204         err = ctrl->ops->set_value(ctrl, val);
205         if (err < 0)
206                 return err;
207         return count;
208 }
209
210 int wf_register_control(struct wf_control *new_ct)
211 {
212         struct wf_control *ct;
213
214         mutex_lock(&wf_lock);
215         list_for_each_entry(ct, &wf_controls, link) {
216                 if (!strcmp(ct->name, new_ct->name)) {
217                         printk(KERN_WARNING "windfarm: trying to register"
218                                " duplicate control %s\n", ct->name);
219                         mutex_unlock(&wf_lock);
220                         return -EEXIST;
221                 }
222         }
223         kref_init(&new_ct->ref);
224         list_add(&new_ct->link, &wf_controls);
225
226         sysfs_attr_init(&new_ct->attr.attr);
227         new_ct->attr.attr.name = new_ct->name;
228         new_ct->attr.attr.mode = 0644;
229         new_ct->attr.show = wf_show_control;
230         new_ct->attr.store = wf_store_control;
231         if (device_create_file(&wf_platform_device.dev, &new_ct->attr))
232                 printk(KERN_WARNING "windfarm: device_create_file failed"
233                         " for %s\n", new_ct->name);
234                 /* the subsystem still does useful work without the file */
235
236         DBG("wf: Registered control %s\n", new_ct->name);
237
238         wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
239         mutex_unlock(&wf_lock);
240
241         return 0;
242 }
243 EXPORT_SYMBOL_GPL(wf_register_control);
244
245 void wf_unregister_control(struct wf_control *ct)
246 {
247         mutex_lock(&wf_lock);
248         list_del(&ct->link);
249         mutex_unlock(&wf_lock);
250
251         DBG("wf: Unregistered control %s\n", ct->name);
252
253         kref_put(&ct->ref, wf_control_release);
254 }
255 EXPORT_SYMBOL_GPL(wf_unregister_control);
256
257 int wf_get_control(struct wf_control *ct)
258 {
259         if (!try_module_get(ct->ops->owner))
260                 return -ENODEV;
261         kref_get(&ct->ref);
262         return 0;
263 }
264 EXPORT_SYMBOL_GPL(wf_get_control);
265
266 void wf_put_control(struct wf_control *ct)
267 {
268         struct module *mod = ct->ops->owner;
269         kref_put(&ct->ref, wf_control_release);
270         module_put(mod);
271 }
272 EXPORT_SYMBOL_GPL(wf_put_control);
273
274
275 /*
276  * Sensors
277  */
278
279
280 static void wf_sensor_release(struct kref *kref)
281 {
282         struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
283
284         DBG("wf: Deleting sensor %s\n", sr->name);
285
286         if (sr->ops && sr->ops->release)
287                 sr->ops->release(sr);
288         else
289                 kfree(sr);
290 }
291
292 static ssize_t wf_show_sensor(struct device *dev,
293                               struct device_attribute *attr, char *buf)
294 {
295         struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
296         s32 val = 0;
297         int err;
298
299         err = sens->ops->get_value(sens, &val);
300         if (err < 0)
301                 return err;
302         return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
303 }
304
305 int wf_register_sensor(struct wf_sensor *new_sr)
306 {
307         struct wf_sensor *sr;
308
309         mutex_lock(&wf_lock);
310         list_for_each_entry(sr, &wf_sensors, link) {
311                 if (!strcmp(sr->name, new_sr->name)) {
312                         printk(KERN_WARNING "windfarm: trying to register"
313                                " duplicate sensor %s\n", sr->name);
314                         mutex_unlock(&wf_lock);
315                         return -EEXIST;
316                 }
317         }
318         kref_init(&new_sr->ref);
319         list_add(&new_sr->link, &wf_sensors);
320
321         sysfs_attr_init(&new_sr->attr.attr);
322         new_sr->attr.attr.name = new_sr->name;
323         new_sr->attr.attr.mode = 0444;
324         new_sr->attr.show = wf_show_sensor;
325         new_sr->attr.store = NULL;
326         if (device_create_file(&wf_platform_device.dev, &new_sr->attr))
327                 printk(KERN_WARNING "windfarm: device_create_file failed"
328                         " for %s\n", new_sr->name);
329                 /* the subsystem still does useful work without the file */
330
331         DBG("wf: Registered sensor %s\n", new_sr->name);
332
333         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
334         mutex_unlock(&wf_lock);
335
336         return 0;
337 }
338 EXPORT_SYMBOL_GPL(wf_register_sensor);
339
340 void wf_unregister_sensor(struct wf_sensor *sr)
341 {
342         mutex_lock(&wf_lock);
343         list_del(&sr->link);
344         mutex_unlock(&wf_lock);
345
346         DBG("wf: Unregistered sensor %s\n", sr->name);
347
348         wf_put_sensor(sr);
349 }
350 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
351
352 int wf_get_sensor(struct wf_sensor *sr)
353 {
354         if (!try_module_get(sr->ops->owner))
355                 return -ENODEV;
356         kref_get(&sr->ref);
357         return 0;
358 }
359 EXPORT_SYMBOL_GPL(wf_get_sensor);
360
361 void wf_put_sensor(struct wf_sensor *sr)
362 {
363         struct module *mod = sr->ops->owner;
364         kref_put(&sr->ref, wf_sensor_release);
365         module_put(mod);
366 }
367 EXPORT_SYMBOL_GPL(wf_put_sensor);
368
369
370 /*
371  * Client & notification
372  */
373
374 int wf_register_client(struct notifier_block *nb)
375 {
376         int rc;
377         struct wf_control *ct;
378         struct wf_sensor *sr;
379
380         mutex_lock(&wf_lock);
381         rc = blocking_notifier_chain_register(&wf_client_list, nb);
382         if (rc != 0)
383                 goto bail;
384         wf_client_count++;
385         list_for_each_entry(ct, &wf_controls, link)
386                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
387         list_for_each_entry(sr, &wf_sensors, link)
388                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
389         if (wf_client_count == 1)
390                 wf_start_thread();
391  bail:
392         mutex_unlock(&wf_lock);
393         return rc;
394 }
395 EXPORT_SYMBOL_GPL(wf_register_client);
396
397 int wf_unregister_client(struct notifier_block *nb)
398 {
399         mutex_lock(&wf_lock);
400         blocking_notifier_chain_unregister(&wf_client_list, nb);
401         wf_client_count--;
402         if (wf_client_count == 0)
403                 wf_stop_thread();
404         mutex_unlock(&wf_lock);
405
406         return 0;
407 }
408 EXPORT_SYMBOL_GPL(wf_unregister_client);
409
410 void wf_set_overtemp(void)
411 {
412         mutex_lock(&wf_lock);
413         wf_overtemp++;
414         if (wf_overtemp == 1) {
415                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
416                 wf_overtemp_counter = 0;
417                 wf_notify(WF_EVENT_OVERTEMP, NULL);
418         }
419         mutex_unlock(&wf_lock);
420 }
421 EXPORT_SYMBOL_GPL(wf_set_overtemp);
422
423 void wf_clear_overtemp(void)
424 {
425         mutex_lock(&wf_lock);
426         WARN_ON(wf_overtemp == 0);
427         if (wf_overtemp == 0) {
428                 mutex_unlock(&wf_lock);
429                 return;
430         }
431         wf_overtemp--;
432         if (wf_overtemp == 0) {
433                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
434                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
435         }
436         mutex_unlock(&wf_lock);
437 }
438 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
439
440 static int __init windfarm_core_init(void)
441 {
442         DBG("wf: core loaded\n");
443
444         platform_device_register(&wf_platform_device);
445         return 0;
446 }
447
448 static void __exit windfarm_core_exit(void)
449 {
450         BUG_ON(wf_client_count != 0);
451
452         DBG("wf: core unloaded\n");
453
454         platform_device_unregister(&wf_platform_device);
455 }
456
457
458 module_init(windfarm_core_init);
459 module_exit(windfarm_core_exit);
460
461 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
462 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
463 MODULE_LICENSE("GPL");
464