Loading...
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
53static LIST_HEAD(wf_controls);
54static LIST_HEAD(wf_sensors);
55static DEFINE_MUTEX(wf_lock);
56static BLOCKING_NOTIFIER_HEAD(wf_client_list);
57static int wf_client_count;
58static unsigned int wf_overtemp;
59static unsigned int wf_overtemp_counter;
60struct task_struct *wf_thread;
61
62static struct platform_device wf_platform_device = {
63 .name = "windfarm",
64};
65
66/*
67 * Utilities & tick thread
68 */
69
70static inline void wf_notify(int event, void *param)
71{
72 blocking_notifier_call_chain(&wf_client_list, event, param);
73}
74
75int 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}
87EXPORT_SYMBOL_GPL(wf_critical_overtemp);
88
89static 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
129static 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
140static 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
151static 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
163static 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 const char *typestr;
168 s32 val = 0;
169 int err;
170
171 err = ctrl->ops->get_value(ctrl, &val);
172 if (err < 0) {
173 if (err == -EFAULT)
174 return sprintf(buf, "<HW FAULT>\n");
175 return err;
176 }
177 switch(ctrl->type) {
178 case WF_CONTROL_RPM_FAN:
179 typestr = " RPM";
180 break;
181 case WF_CONTROL_PWM_FAN:
182 typestr = " %";
183 break;
184 default:
185 typestr = "";
186 }
187 return sprintf(buf, "%d%s\n", val, typestr);
188}
189
190/* This is really only for debugging... */
191static ssize_t wf_store_control(struct device *dev,
192 struct device_attribute *attr,
193 const char *buf, size_t count)
194{
195 struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
196 int val;
197 int err;
198 char *endp;
199
200 val = simple_strtoul(buf, &endp, 0);
201 while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
202 ++endp;
203 if (endp - buf < count)
204 return -EINVAL;
205 err = ctrl->ops->set_value(ctrl, val);
206 if (err < 0)
207 return err;
208 return count;
209}
210
211int wf_register_control(struct wf_control *new_ct)
212{
213 struct wf_control *ct;
214
215 mutex_lock(&wf_lock);
216 list_for_each_entry(ct, &wf_controls, link) {
217 if (!strcmp(ct->name, new_ct->name)) {
218 printk(KERN_WARNING "windfarm: trying to register"
219 " duplicate control %s\n", ct->name);
220 mutex_unlock(&wf_lock);
221 return -EEXIST;
222 }
223 }
224 kref_init(&new_ct->ref);
225 list_add(&new_ct->link, &wf_controls);
226
227 sysfs_attr_init(&new_ct->attr.attr);
228 new_ct->attr.attr.name = new_ct->name;
229 new_ct->attr.attr.mode = 0644;
230 new_ct->attr.show = wf_show_control;
231 new_ct->attr.store = wf_store_control;
232 if (device_create_file(&wf_platform_device.dev, &new_ct->attr))
233 printk(KERN_WARNING "windfarm: device_create_file failed"
234 " for %s\n", new_ct->name);
235 /* the subsystem still does useful work without the file */
236
237 DBG("wf: Registered control %s\n", new_ct->name);
238
239 wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
240 mutex_unlock(&wf_lock);
241
242 return 0;
243}
244EXPORT_SYMBOL_GPL(wf_register_control);
245
246void wf_unregister_control(struct wf_control *ct)
247{
248 mutex_lock(&wf_lock);
249 list_del(&ct->link);
250 mutex_unlock(&wf_lock);
251
252 DBG("wf: Unregistered control %s\n", ct->name);
253
254 kref_put(&ct->ref, wf_control_release);
255}
256EXPORT_SYMBOL_GPL(wf_unregister_control);
257
258struct wf_control * wf_find_control(const char *name)
259{
260 struct wf_control *ct;
261
262 mutex_lock(&wf_lock);
263 list_for_each_entry(ct, &wf_controls, link) {
264 if (!strcmp(ct->name, name)) {
265 if (wf_get_control(ct))
266 ct = NULL;
267 mutex_unlock(&wf_lock);
268 return ct;
269 }
270 }
271 mutex_unlock(&wf_lock);
272 return NULL;
273}
274EXPORT_SYMBOL_GPL(wf_find_control);
275
276int wf_get_control(struct wf_control *ct)
277{
278 if (!try_module_get(ct->ops->owner))
279 return -ENODEV;
280 kref_get(&ct->ref);
281 return 0;
282}
283EXPORT_SYMBOL_GPL(wf_get_control);
284
285void wf_put_control(struct wf_control *ct)
286{
287 struct module *mod = ct->ops->owner;
288 kref_put(&ct->ref, wf_control_release);
289 module_put(mod);
290}
291EXPORT_SYMBOL_GPL(wf_put_control);
292
293
294/*
295 * Sensors
296 */
297
298
299static void wf_sensor_release(struct kref *kref)
300{
301 struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
302
303 DBG("wf: Deleting sensor %s\n", sr->name);
304
305 if (sr->ops && sr->ops->release)
306 sr->ops->release(sr);
307 else
308 kfree(sr);
309}
310
311static ssize_t wf_show_sensor(struct device *dev,
312 struct device_attribute *attr, char *buf)
313{
314 struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
315 s32 val = 0;
316 int err;
317
318 err = sens->ops->get_value(sens, &val);
319 if (err < 0)
320 return err;
321 return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
322}
323
324int wf_register_sensor(struct wf_sensor *new_sr)
325{
326 struct wf_sensor *sr;
327
328 mutex_lock(&wf_lock);
329 list_for_each_entry(sr, &wf_sensors, link) {
330 if (!strcmp(sr->name, new_sr->name)) {
331 printk(KERN_WARNING "windfarm: trying to register"
332 " duplicate sensor %s\n", sr->name);
333 mutex_unlock(&wf_lock);
334 return -EEXIST;
335 }
336 }
337 kref_init(&new_sr->ref);
338 list_add(&new_sr->link, &wf_sensors);
339
340 sysfs_attr_init(&new_sr->attr.attr);
341 new_sr->attr.attr.name = new_sr->name;
342 new_sr->attr.attr.mode = 0444;
343 new_sr->attr.show = wf_show_sensor;
344 new_sr->attr.store = NULL;
345 if (device_create_file(&wf_platform_device.dev, &new_sr->attr))
346 printk(KERN_WARNING "windfarm: device_create_file failed"
347 " for %s\n", new_sr->name);
348 /* the subsystem still does useful work without the file */
349
350 DBG("wf: Registered sensor %s\n", new_sr->name);
351
352 wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
353 mutex_unlock(&wf_lock);
354
355 return 0;
356}
357EXPORT_SYMBOL_GPL(wf_register_sensor);
358
359void wf_unregister_sensor(struct wf_sensor *sr)
360{
361 mutex_lock(&wf_lock);
362 list_del(&sr->link);
363 mutex_unlock(&wf_lock);
364
365 DBG("wf: Unregistered sensor %s\n", sr->name);
366
367 wf_put_sensor(sr);
368}
369EXPORT_SYMBOL_GPL(wf_unregister_sensor);
370
371struct wf_sensor * wf_find_sensor(const char *name)
372{
373 struct wf_sensor *sr;
374
375 mutex_lock(&wf_lock);
376 list_for_each_entry(sr, &wf_sensors, link) {
377 if (!strcmp(sr->name, name)) {
378 if (wf_get_sensor(sr))
379 sr = NULL;
380 mutex_unlock(&wf_lock);
381 return sr;
382 }
383 }
384 mutex_unlock(&wf_lock);
385 return NULL;
386}
387EXPORT_SYMBOL_GPL(wf_find_sensor);
388
389int wf_get_sensor(struct wf_sensor *sr)
390{
391 if (!try_module_get(sr->ops->owner))
392 return -ENODEV;
393 kref_get(&sr->ref);
394 return 0;
395}
396EXPORT_SYMBOL_GPL(wf_get_sensor);
397
398void wf_put_sensor(struct wf_sensor *sr)
399{
400 struct module *mod = sr->ops->owner;
401 kref_put(&sr->ref, wf_sensor_release);
402 module_put(mod);
403}
404EXPORT_SYMBOL_GPL(wf_put_sensor);
405
406
407/*
408 * Client & notification
409 */
410
411int wf_register_client(struct notifier_block *nb)
412{
413 int rc;
414 struct wf_control *ct;
415 struct wf_sensor *sr;
416
417 mutex_lock(&wf_lock);
418 rc = blocking_notifier_chain_register(&wf_client_list, nb);
419 if (rc != 0)
420 goto bail;
421 wf_client_count++;
422 list_for_each_entry(ct, &wf_controls, link)
423 wf_notify(WF_EVENT_NEW_CONTROL, ct);
424 list_for_each_entry(sr, &wf_sensors, link)
425 wf_notify(WF_EVENT_NEW_SENSOR, sr);
426 if (wf_client_count == 1)
427 wf_start_thread();
428 bail:
429 mutex_unlock(&wf_lock);
430 return rc;
431}
432EXPORT_SYMBOL_GPL(wf_register_client);
433
434int wf_unregister_client(struct notifier_block *nb)
435{
436 mutex_lock(&wf_lock);
437 blocking_notifier_chain_unregister(&wf_client_list, nb);
438 wf_client_count++;
439 if (wf_client_count == 0)
440 wf_stop_thread();
441 mutex_unlock(&wf_lock);
442
443 return 0;
444}
445EXPORT_SYMBOL_GPL(wf_unregister_client);
446
447void wf_set_overtemp(void)
448{
449 mutex_lock(&wf_lock);
450 wf_overtemp++;
451 if (wf_overtemp == 1) {
452 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
453 wf_overtemp_counter = 0;
454 wf_notify(WF_EVENT_OVERTEMP, NULL);
455 }
456 mutex_unlock(&wf_lock);
457}
458EXPORT_SYMBOL_GPL(wf_set_overtemp);
459
460void wf_clear_overtemp(void)
461{
462 mutex_lock(&wf_lock);
463 WARN_ON(wf_overtemp == 0);
464 if (wf_overtemp == 0) {
465 mutex_unlock(&wf_lock);
466 return;
467 }
468 wf_overtemp--;
469 if (wf_overtemp == 0) {
470 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
471 wf_notify(WF_EVENT_NORMALTEMP, NULL);
472 }
473 mutex_unlock(&wf_lock);
474}
475EXPORT_SYMBOL_GPL(wf_clear_overtemp);
476
477int wf_is_overtemp(void)
478{
479 return (wf_overtemp != 0);
480}
481EXPORT_SYMBOL_GPL(wf_is_overtemp);
482
483static int __init windfarm_core_init(void)
484{
485 DBG("wf: core loaded\n");
486
487 platform_device_register(&wf_platform_device);
488 return 0;
489}
490
491static void __exit windfarm_core_exit(void)
492{
493 BUG_ON(wf_client_count != 0);
494
495 DBG("wf: core unloaded\n");
496
497 platform_device_unregister(&wf_platform_device);
498}
499
500
501module_init(windfarm_core_init);
502module_exit(windfarm_core_exit);
503
504MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
505MODULE_DESCRIPTION("Core component of PowerMac thermal control");
506MODULE_LICENSE("GPL");
507