Merge branch 'address-masking'
[linux-2.6-microblaze.git] / drivers / macintosh / windfarm_core.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Windfarm PowerMac thermal control. Core
4  *
5  * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
6  *                    <benh@kernel.crashing.org>
7  *
8  * This core code tracks the list of sensors & controls, register
9  * clients, and holds the kernel thread used for control.
10  *
11  * TODO:
12  *
13  * Add some information about sensor/control type and data format to
14  * sensors/controls, and have the sysfs attribute stuff be moved
15  * generically here instead of hard coded in the platform specific
16  * driver as it us currently
17  *
18  * This however requires solving some annoying lifetime issues with
19  * sysfs which doesn't seem to have lifetime rules for struct attribute,
20  * I may have to create full features kobjects for every sensor/control
21  * instead which is a bit of an overkill imho
22  */
23
24 #include <linux/types.h>
25 #include <linux/errno.h>
26 #include <linux/kernel.h>
27 #include <linux/slab.h>
28 #include <linux/init.h>
29 #include <linux/spinlock.h>
30 #include <linux/kthread.h>
31 #include <linux/jiffies.h>
32 #include <linux/reboot.h>
33 #include <linux/device.h>
34 #include <linux/platform_device.h>
35 #include <linux/mutex.h>
36 #include <linux/freezer.h>
37
38 #include "windfarm.h"
39
40 #define VERSION "0.2"
41
42 #undef DEBUG
43
44 #ifdef DEBUG
45 #define DBG(args...)    printk(args)
46 #else
47 #define DBG(args...)    do { } while(0)
48 #endif
49
50 static LIST_HEAD(wf_controls);
51 static LIST_HEAD(wf_sensors);
52 static DEFINE_MUTEX(wf_lock);
53 static BLOCKING_NOTIFIER_HEAD(wf_client_list);
54 static int wf_client_count;
55 static unsigned int wf_overtemp;
56 static unsigned int wf_overtemp_counter;
57 static struct task_struct *wf_thread;
58
59 static struct platform_device wf_platform_device = {
60         .name   = "windfarm",
61 };
62
63 /*
64  * Utilities & tick thread
65  */
66
67 static inline void wf_notify(int event, void *param)
68 {
69         blocking_notifier_call_chain(&wf_client_list, event, param);
70 }
71
72 static int wf_critical_overtemp(void)
73 {
74         static char const critical_overtemp_path[] = "/sbin/critical_overtemp";
75         char *argv[] = { (char *)critical_overtemp_path, NULL };
76         static char *envp[] = { "HOME=/",
77                                 "TERM=linux",
78                                 "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
79                                 NULL };
80
81         return call_usermodehelper(critical_overtemp_path,
82                                    argv, envp, UMH_WAIT_EXEC);
83 }
84
85 static int wf_thread_func(void *data)
86 {
87         unsigned long next, delay;
88
89         next = jiffies;
90
91         DBG("wf: thread started\n");
92
93         set_freezable();
94         while (!kthread_should_stop()) {
95                 try_to_freeze();
96
97                 if (time_after_eq(jiffies, next)) {
98                         wf_notify(WF_EVENT_TICK, NULL);
99                         if (wf_overtemp) {
100                                 wf_overtemp_counter++;
101                                 /* 10 seconds overtemp, notify userland */
102                                 if (wf_overtemp_counter > 10)
103                                         wf_critical_overtemp();
104                                 /* 30 seconds, shutdown */
105                                 if (wf_overtemp_counter > 30) {
106                                         printk(KERN_ERR "windfarm: Overtemp "
107                                                "for more than 30"
108                                                " seconds, shutting down\n");
109                                         machine_power_off();
110                                 }
111                         }
112                         next += HZ;
113                 }
114
115                 delay = next - jiffies;
116                 if (delay <= HZ)
117                         schedule_timeout_interruptible(delay);
118         }
119
120         DBG("wf: thread stopped\n");
121
122         return 0;
123 }
124
125 static void wf_start_thread(void)
126 {
127         wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
128         if (IS_ERR(wf_thread)) {
129                 printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
130                        PTR_ERR(wf_thread));
131                 wf_thread = NULL;
132         }
133 }
134
135
136 static void wf_stop_thread(void)
137 {
138         if (wf_thread)
139                 kthread_stop(wf_thread);
140         wf_thread = NULL;
141 }
142
143 /*
144  * Controls
145  */
146
147 static void wf_control_release(struct kref *kref)
148 {
149         struct wf_control *ct = container_of(kref, struct wf_control, ref);
150
151         DBG("wf: Deleting control %s\n", ct->name);
152
153         if (ct->ops && ct->ops->release)
154                 ct->ops->release(ct);
155         else
156                 kfree(ct);
157 }
158
159 static ssize_t wf_show_control(struct device *dev,
160                                struct device_attribute *attr, char *buf)
161 {
162         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
163         const char *typestr;
164         s32 val = 0;
165         int err;
166
167         err = ctrl->ops->get_value(ctrl, &val);
168         if (err < 0) {
169                 if (err == -EFAULT)
170                         return sprintf(buf, "<HW FAULT>\n");
171                 return err;
172         }
173         switch(ctrl->type) {
174         case WF_CONTROL_RPM_FAN:
175                 typestr = " RPM";
176                 break;
177         case WF_CONTROL_PWM_FAN:
178                 typestr = " %";
179                 break;
180         default:
181                 typestr = "";
182         }
183         return sprintf(buf, "%d%s\n", val, typestr);
184 }
185
186 /* This is really only for debugging... */
187 static ssize_t wf_store_control(struct device *dev,
188                                 struct device_attribute *attr,
189                                 const char *buf, size_t count)
190 {
191         struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
192         int val;
193         int err;
194         char *endp;
195
196         val = simple_strtoul(buf, &endp, 0);
197         while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
198                 ++endp;
199         if (endp - buf < count)
200                 return -EINVAL;
201         err = ctrl->ops->set_value(ctrl, val);
202         if (err < 0)
203                 return err;
204         return count;
205 }
206
207 int wf_register_control(struct wf_control *new_ct)
208 {
209         struct wf_control *ct;
210
211         mutex_lock(&wf_lock);
212         list_for_each_entry(ct, &wf_controls, link) {
213                 if (!strcmp(ct->name, new_ct->name)) {
214                         printk(KERN_WARNING "windfarm: trying to register"
215                                " duplicate control %s\n", ct->name);
216                         mutex_unlock(&wf_lock);
217                         return -EEXIST;
218                 }
219         }
220         kref_init(&new_ct->ref);
221         list_add(&new_ct->link, &wf_controls);
222
223         sysfs_attr_init(&new_ct->attr.attr);
224         new_ct->attr.attr.name = new_ct->name;
225         new_ct->attr.attr.mode = 0644;
226         new_ct->attr.show = wf_show_control;
227         new_ct->attr.store = wf_store_control;
228         if (device_create_file(&wf_platform_device.dev, &new_ct->attr))
229                 printk(KERN_WARNING "windfarm: device_create_file failed"
230                         " for %s\n", new_ct->name);
231                 /* the subsystem still does useful work without the file */
232
233         DBG("wf: Registered control %s\n", new_ct->name);
234
235         wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
236         mutex_unlock(&wf_lock);
237
238         return 0;
239 }
240 EXPORT_SYMBOL_GPL(wf_register_control);
241
242 void wf_unregister_control(struct wf_control *ct)
243 {
244         mutex_lock(&wf_lock);
245         list_del(&ct->link);
246         mutex_unlock(&wf_lock);
247
248         DBG("wf: Unregistered control %s\n", ct->name);
249
250         kref_put(&ct->ref, wf_control_release);
251 }
252 EXPORT_SYMBOL_GPL(wf_unregister_control);
253
254 int wf_get_control(struct wf_control *ct)
255 {
256         if (!try_module_get(ct->ops->owner))
257                 return -ENODEV;
258         kref_get(&ct->ref);
259         return 0;
260 }
261 EXPORT_SYMBOL_GPL(wf_get_control);
262
263 void wf_put_control(struct wf_control *ct)
264 {
265         struct module *mod = ct->ops->owner;
266         kref_put(&ct->ref, wf_control_release);
267         module_put(mod);
268 }
269 EXPORT_SYMBOL_GPL(wf_put_control);
270
271
272 /*
273  * Sensors
274  */
275
276
277 static void wf_sensor_release(struct kref *kref)
278 {
279         struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
280
281         DBG("wf: Deleting sensor %s\n", sr->name);
282
283         if (sr->ops && sr->ops->release)
284                 sr->ops->release(sr);
285         else
286                 kfree(sr);
287 }
288
289 static ssize_t wf_show_sensor(struct device *dev,
290                               struct device_attribute *attr, char *buf)
291 {
292         struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
293         s32 val = 0;
294         int err;
295
296         err = sens->ops->get_value(sens, &val);
297         if (err < 0)
298                 return err;
299         return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
300 }
301
302 int wf_register_sensor(struct wf_sensor *new_sr)
303 {
304         struct wf_sensor *sr;
305
306         mutex_lock(&wf_lock);
307         list_for_each_entry(sr, &wf_sensors, link) {
308                 if (!strcmp(sr->name, new_sr->name)) {
309                         printk(KERN_WARNING "windfarm: trying to register"
310                                " duplicate sensor %s\n", sr->name);
311                         mutex_unlock(&wf_lock);
312                         return -EEXIST;
313                 }
314         }
315         kref_init(&new_sr->ref);
316         list_add(&new_sr->link, &wf_sensors);
317
318         sysfs_attr_init(&new_sr->attr.attr);
319         new_sr->attr.attr.name = new_sr->name;
320         new_sr->attr.attr.mode = 0444;
321         new_sr->attr.show = wf_show_sensor;
322         new_sr->attr.store = NULL;
323         if (device_create_file(&wf_platform_device.dev, &new_sr->attr))
324                 printk(KERN_WARNING "windfarm: device_create_file failed"
325                         " for %s\n", new_sr->name);
326                 /* the subsystem still does useful work without the file */
327
328         DBG("wf: Registered sensor %s\n", new_sr->name);
329
330         wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
331         mutex_unlock(&wf_lock);
332
333         return 0;
334 }
335 EXPORT_SYMBOL_GPL(wf_register_sensor);
336
337 void wf_unregister_sensor(struct wf_sensor *sr)
338 {
339         mutex_lock(&wf_lock);
340         list_del(&sr->link);
341         mutex_unlock(&wf_lock);
342
343         DBG("wf: Unregistered sensor %s\n", sr->name);
344
345         wf_put_sensor(sr);
346 }
347 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
348
349 int wf_get_sensor(struct wf_sensor *sr)
350 {
351         if (!try_module_get(sr->ops->owner))
352                 return -ENODEV;
353         kref_get(&sr->ref);
354         return 0;
355 }
356 EXPORT_SYMBOL_GPL(wf_get_sensor);
357
358 void wf_put_sensor(struct wf_sensor *sr)
359 {
360         struct module *mod = sr->ops->owner;
361         kref_put(&sr->ref, wf_sensor_release);
362         module_put(mod);
363 }
364 EXPORT_SYMBOL_GPL(wf_put_sensor);
365
366
367 /*
368  * Client & notification
369  */
370
371 int wf_register_client(struct notifier_block *nb)
372 {
373         int rc;
374         struct wf_control *ct;
375         struct wf_sensor *sr;
376
377         mutex_lock(&wf_lock);
378         rc = blocking_notifier_chain_register(&wf_client_list, nb);
379         if (rc != 0)
380                 goto bail;
381         wf_client_count++;
382         list_for_each_entry(ct, &wf_controls, link)
383                 wf_notify(WF_EVENT_NEW_CONTROL, ct);
384         list_for_each_entry(sr, &wf_sensors, link)
385                 wf_notify(WF_EVENT_NEW_SENSOR, sr);
386         if (wf_client_count == 1)
387                 wf_start_thread();
388  bail:
389         mutex_unlock(&wf_lock);
390         return rc;
391 }
392 EXPORT_SYMBOL_GPL(wf_register_client);
393
394 int wf_unregister_client(struct notifier_block *nb)
395 {
396         mutex_lock(&wf_lock);
397         blocking_notifier_chain_unregister(&wf_client_list, nb);
398         wf_client_count--;
399         if (wf_client_count == 0)
400                 wf_stop_thread();
401         mutex_unlock(&wf_lock);
402
403         return 0;
404 }
405 EXPORT_SYMBOL_GPL(wf_unregister_client);
406
407 void wf_set_overtemp(void)
408 {
409         mutex_lock(&wf_lock);
410         wf_overtemp++;
411         if (wf_overtemp == 1) {
412                 printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
413                 wf_overtemp_counter = 0;
414                 wf_notify(WF_EVENT_OVERTEMP, NULL);
415         }
416         mutex_unlock(&wf_lock);
417 }
418 EXPORT_SYMBOL_GPL(wf_set_overtemp);
419
420 void wf_clear_overtemp(void)
421 {
422         mutex_lock(&wf_lock);
423         WARN_ON(wf_overtemp == 0);
424         if (wf_overtemp == 0) {
425                 mutex_unlock(&wf_lock);
426                 return;
427         }
428         wf_overtemp--;
429         if (wf_overtemp == 0) {
430                 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
431                 wf_notify(WF_EVENT_NORMALTEMP, NULL);
432         }
433         mutex_unlock(&wf_lock);
434 }
435 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
436
437 static int __init windfarm_core_init(void)
438 {
439         DBG("wf: core loaded\n");
440
441         platform_device_register(&wf_platform_device);
442         return 0;
443 }
444
445 static void __exit windfarm_core_exit(void)
446 {
447         BUG_ON(wf_client_count != 0);
448
449         DBG("wf: core unloaded\n");
450
451         platform_device_unregister(&wf_platform_device);
452 }
453
454
455 module_init(windfarm_core_init);
456 module_exit(windfarm_core_exit);
457
458 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
459 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
460 MODULE_LICENSE("GPL");
461