device_attributes: add sysfs_attr_init() for dynamic attributes
[linux-2.6.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 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,
85                                    argv, envp, UMH_WAIT_EXEC);
86 }
87 EXPORT_SYMBOL_GPL(wf_critical_overtemp);
88
89 static int wf_thread_func(void *data)
90 {
91         unsigned long next, delay;
92
93         next = jiffies;
94
95         DBG("wf: thread started\n");
96
97         set_freezable();
98         while (!kthread_should_stop()) {
99                 try_to_freeze();
100
101                 if (time_after_eq(jiffies, next)) {
102                         wf_notify(WF_EVENT_TICK, NULL);
103                         if (wf_overtemp) {
104                                 wf_overtemp_counter++;
105                                 /* 10 seconds overtemp, notify userland */
106                                 if (wf_overtemp_counter > 10)
107                                         wf_critical_overtemp();
108                                 /* 30 seconds, shutdown */
109                                 if (wf_overtemp_counter > 30) {
110                                         printk(KERN_ERR "windfarm: Overtemp "
111                                                "for more than 30"
112                                                " seconds, shutting down\n");
113                                         machine_power_off();
114                                 }
115                         }
116                         next += HZ;
117                 }
118
119                 delay = next - jiffies;
120                 if (delay <= HZ)
121                         schedule_timeout_interruptible(delay);
122         }
123
124         DBG("wf: thread stopped\n");
125
126         return 0;
127 }
128
129 static void wf_start_thread(void)
130 {
131         wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
132         if (IS_ERR(wf_thread)) {
133                 printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
134                        PTR_ERR(wf_thread));
135                 wf_thread = NULL;
136         }
137 }
138
139
140 static void wf_stop_thread(void)
141 {
142         if (wf_thread)
143                 kthread_stop(wf_thread);
144         wf_thread = NULL;
145 }
146
147 /*
148  * Controls
149  */
150
151 static void wf_control_release(struct kref *kref)
152 {
153         struct wf_control *ct = container_of(kref, struct wf_control, ref);
154
155         DBG("wf: Deleting control %s\n", ct->name);
156
157         if (ct->ops && ct->ops->release)
158                 ct->ops->release(ct);
159         else
160                 kfree(ct);
161 }
162
163 static ssize_t wf_show_control(struct device *dev,
164                                struct device_attribute *attr, char *buf)
165 {
166         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
167         s32 val = 0;
168         int err;
169
170         err = ctrl->ops->get_value(ctrl, &val);
171         if (err < 0)
172                 return err;
173         return sprintf(buf, "%d\n", val);
174 }
175
176 /* This is really only for debugging... */
177 static ssize_t wf_store_control(struct device *dev,
178                                 struct device_attribute *attr,
179                                 const char *buf, size_t count)
180 {
181         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
182         int val;
183         int err;
184         char *endp;
185
186         val = simple_strtoul(buf, &endp, 0);
187         while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
188                 ++endp;
189         if (endp - buf < count)
190                 return -EINVAL;
191         err = ctrl->ops->set_value(ctrl, val);
192         if (err < 0)
193                 return err;
194         return count;
195 }
196
197 int wf_register_control(struct wf_control *new_ct)
198 {
199         struct wf_control *ct;
200
201         mutex_lock(&wf_lock);
202         list_for_each_entry(ct, &wf_controls, link) {
203                 if (!strcmp(ct->name, new_ct->name)) {
204                         printk(KERN_WARNING "windfarm: trying to register"
205                                " duplicate control %s\n", ct->name);
206                         mutex_unlock(&wf_lock);
207                         return -EEXIST;
208                 }
209         }
210         kref_init(&new_ct->ref);
211         list_add(&new_ct->link, &wf_controls);
212
213         sysfs_attr_init(&new_ct->attr.attr);
214         new_ct->attr.attr.name = new_ct->name;
215         new_ct->attr.attr.mode = 0644;
216         new_ct->attr.show = wf_show_control;
217         new_ct->attr.store = wf_store_control;
218         if (device_create_file(&wf_platform_device.dev, &new_ct->attr))
219                 printk(KERN_WARNING "windfarm: device_create_file failed"
220                         " for %s\n", new_ct->name);
221                 /* the subsystem still does useful work without the file */
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         sysfs_attr_init(&new_sr->attr.attr);
327         new_sr->attr.attr.name = new_sr->name;
328         new_sr->attr.attr.mode = 0444;
329         new_sr->attr.show = wf_show_sensor;
330         new_sr->attr.store = NULL;
331         if (device_create_file(&wf_platform_device.dev, &new_sr->attr))
332                 printk(KERN_WARNING "windfarm: device_create_file failed"
333                         " for %s\n", new_sr->name);
334                 /* the subsystem still does useful work without the file */
335
336         DBG("wf: Registered sensor %s\n", new_sr->name);
337
338         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
339         mutex_unlock(&wf_lock);
340
341         return 0;
342 }
343 EXPORT_SYMBOL_GPL(wf_register_sensor);
344
345 void wf_unregister_sensor(struct wf_sensor *sr)
346 {
347         mutex_lock(&wf_lock);
348         list_del(&sr->link);
349         mutex_unlock(&wf_lock);
350
351         DBG("wf: Unregistered sensor %s\n", sr->name);
352
353         wf_put_sensor(sr);
354 }
355 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
356
357 struct wf_sensor * wf_find_sensor(const char *name)
358 {
359         struct wf_sensor *sr;
360
361         mutex_lock(&wf_lock);
362         list_for_each_entry(sr, &wf_sensors, link) {
363                 if (!strcmp(sr->name, name)) {
364                         if (wf_get_sensor(sr))
365                                 sr = NULL;
366                         mutex_unlock(&wf_lock);
367                         return sr;
368                 }
369         }
370         mutex_unlock(&wf_lock);
371         return NULL;
372 }
373 EXPORT_SYMBOL_GPL(wf_find_sensor);
374
375 int wf_get_sensor(struct wf_sensor *sr)
376 {
377         if (!try_module_get(sr->ops->owner))
378                 return -ENODEV;
379         kref_get(&sr->ref);
380         return 0;
381 }
382 EXPORT_SYMBOL_GPL(wf_get_sensor);
383
384 void wf_put_sensor(struct wf_sensor *sr)
385 {
386         struct module *mod = sr->ops->owner;
387         kref_put(&sr->ref, wf_sensor_release);
388         module_put(mod);
389 }
390 EXPORT_SYMBOL_GPL(wf_put_sensor);
391
392
393 /*
394  * Client & notification
395  */
396
397 int wf_register_client(struct notifier_block *nb)
398 {
399         int rc;
400         struct wf_control *ct;
401         struct wf_sensor *sr;
402
403         mutex_lock(&wf_lock);
404         rc = blocking_notifier_chain_register(&wf_client_list, nb);
405         if (rc != 0)
406                 goto bail;
407         wf_client_count++;
408         list_for_each_entry(ct, &wf_controls, link)
409                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
410         list_for_each_entry(sr, &wf_sensors, link)
411                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
412         if (wf_client_count == 1)
413                 wf_start_thread();
414  bail:
415         mutex_unlock(&wf_lock);
416         return rc;
417 }
418 EXPORT_SYMBOL_GPL(wf_register_client);
419
420 int wf_unregister_client(struct notifier_block *nb)
421 {
422         mutex_lock(&wf_lock);
423         blocking_notifier_chain_unregister(&wf_client_list, nb);
424         wf_client_count++;
425         if (wf_client_count == 0)
426                 wf_stop_thread();
427         mutex_unlock(&wf_lock);
428
429         return 0;
430 }
431 EXPORT_SYMBOL_GPL(wf_unregister_client);
432
433 void wf_set_overtemp(void)
434 {
435         mutex_lock(&wf_lock);
436         wf_overtemp++;
437         if (wf_overtemp == 1) {
438                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
439                 wf_overtemp_counter = 0;
440                 wf_notify(WF_EVENT_OVERTEMP, NULL);
441         }
442         mutex_unlock(&wf_lock);
443 }
444 EXPORT_SYMBOL_GPL(wf_set_overtemp);
445
446 void wf_clear_overtemp(void)
447 {
448         mutex_lock(&wf_lock);
449         WARN_ON(wf_overtemp == 0);
450         if (wf_overtemp == 0) {
451                 mutex_unlock(&wf_lock);
452                 return;
453         }
454         wf_overtemp--;
455         if (wf_overtemp == 0) {
456                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
457                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
458         }
459         mutex_unlock(&wf_lock);
460 }
461 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
462
463 int wf_is_overtemp(void)
464 {
465         return (wf_overtemp != 0);
466 }
467 EXPORT_SYMBOL_GPL(wf_is_overtemp);
468
469 static int __init windfarm_core_init(void)
470 {
471         DBG("wf: core loaded\n");
472
473         /* Don't register on old machines that use therm_pm72 for now */
474         if (of_machine_is_compatible("PowerMac7,2") ||
475             of_machine_is_compatible("PowerMac7,3") ||
476             of_machine_is_compatible("RackMac3,1"))
477                 return -ENODEV;
478         platform_device_register(&wf_platform_device);
479         return 0;
480 }
481
482 static void __exit windfarm_core_exit(void)
483 {
484         BUG_ON(wf_client_count != 0);
485
486         DBG("wf: core unloaded\n");
487
488         platform_device_unregister(&wf_platform_device);
489 }
490
491
492 module_init(windfarm_core_init);
493 module_exit(windfarm_core_exit);
494
495 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
496 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
497 MODULE_LICENSE("GPL");
498