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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
75static 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
88static 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
128static 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
139static 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
150static 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
162static 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... */
190static 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
210int 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}
243EXPORT_SYMBOL_GPL(wf_register_control);
244
245void 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}
255EXPORT_SYMBOL_GPL(wf_unregister_control);
256
257int 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}
264EXPORT_SYMBOL_GPL(wf_get_control);
265
266void 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}
272EXPORT_SYMBOL_GPL(wf_put_control);
273
274
275/*
276 * Sensors
277 */
278
279
280static 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
292static 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
305int 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}
338EXPORT_SYMBOL_GPL(wf_register_sensor);
339
340void 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}
350EXPORT_SYMBOL_GPL(wf_unregister_sensor);
351
352int 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}
359EXPORT_SYMBOL_GPL(wf_get_sensor);
360
361void 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}
367EXPORT_SYMBOL_GPL(wf_put_sensor);
368
369
370/*
371 * Client & notification
372 */
373
374int 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}
395EXPORT_SYMBOL_GPL(wf_register_client);
396
397int 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}
408EXPORT_SYMBOL_GPL(wf_unregister_client);
409
410void 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}
421EXPORT_SYMBOL_GPL(wf_set_overtemp);
422
423void 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}
438EXPORT_SYMBOL_GPL(wf_clear_overtemp);
439
440static 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
448static 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
458module_init(windfarm_core_init);
459module_exit(windfarm_core_exit);
460
461MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
462MODULE_DESCRIPTION("Core component of PowerMac thermal control");
463MODULE_LICENSE("GPL");
464
465

Warning: That file was not part of the compilation database. It may have many parsing errors.