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
50static LIST_HEAD(wf_controls);
51static LIST_HEAD(wf_sensors);
52static DEFINE_MUTEX(wf_lock);
53static BLOCKING_NOTIFIER_HEAD(wf_client_list);
54static int wf_client_count;
55static unsigned int wf_overtemp;
56static unsigned int wf_overtemp_counter;
57static struct task_struct *wf_thread;
58
59static struct platform_device wf_platform_device = {
60 .name = "windfarm",
61};
62
63/*
64 * Utilities & tick thread
65 */
66
67static inline void wf_notify(int event, void *param)
68{
69 blocking_notifier_call_chain(nh: &wf_client_list, val: event, v: param);
70}
71
72static 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(path: critical_overtemp_path,
82 argv, envp, UMH_WAIT_EXEC);
83}
84
85static 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(timeout: delay);
118 }
119
120 DBG("wf: thread stopped\n");
121
122 return 0;
123}
124
125static void wf_start_thread(void)
126{
127 wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
128 if (IS_ERR(ptr: 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
136static void wf_stop_thread(void)
137{
138 if (wf_thread)
139 kthread_stop(k: wf_thread);
140 wf_thread = NULL;
141}
142
143/*
144 * Controls
145 */
146
147static 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(objp: ct);
157}
158
159static 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, fmt: "<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, fmt: "%d%s\n", val, typestr);
184}
185
186/* This is really only for debugging... */
187static 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
207int 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(lock: &wf_lock);
217 return -EEXIST;
218 }
219 }
220 kref_init(kref: &new_ct->ref);
221 list_add(new: &new_ct->link, head: &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(device: &wf_platform_device.dev, entry: &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, param: new_ct);
236 mutex_unlock(lock: &wf_lock);
237
238 return 0;
239}
240EXPORT_SYMBOL_GPL(wf_register_control);
241
242void wf_unregister_control(struct wf_control *ct)
243{
244 mutex_lock(&wf_lock);
245 list_del(entry: &ct->link);
246 mutex_unlock(lock: &wf_lock);
247
248 DBG("wf: Unregistered control %s\n", ct->name);
249
250 kref_put(kref: &ct->ref, release: wf_control_release);
251}
252EXPORT_SYMBOL_GPL(wf_unregister_control);
253
254int wf_get_control(struct wf_control *ct)
255{
256 if (!try_module_get(module: ct->ops->owner))
257 return -ENODEV;
258 kref_get(kref: &ct->ref);
259 return 0;
260}
261EXPORT_SYMBOL_GPL(wf_get_control);
262
263void wf_put_control(struct wf_control *ct)
264{
265 struct module *mod = ct->ops->owner;
266 kref_put(kref: &ct->ref, release: wf_control_release);
267 module_put(module: mod);
268}
269EXPORT_SYMBOL_GPL(wf_put_control);
270
271
272/*
273 * Sensors
274 */
275
276
277static 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(objp: sr);
287}
288
289static 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, fmt: "%d.%03d\n", FIX32TOPRINT(val));
300}
301
302int 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(lock: &wf_lock);
312 return -EEXIST;
313 }
314 }
315 kref_init(kref: &new_sr->ref);
316 list_add(new: &new_sr->link, head: &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(device: &wf_platform_device.dev, entry: &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, param: new_sr);
331 mutex_unlock(lock: &wf_lock);
332
333 return 0;
334}
335EXPORT_SYMBOL_GPL(wf_register_sensor);
336
337void wf_unregister_sensor(struct wf_sensor *sr)
338{
339 mutex_lock(&wf_lock);
340 list_del(entry: &sr->link);
341 mutex_unlock(lock: &wf_lock);
342
343 DBG("wf: Unregistered sensor %s\n", sr->name);
344
345 wf_put_sensor(sr);
346}
347EXPORT_SYMBOL_GPL(wf_unregister_sensor);
348
349int wf_get_sensor(struct wf_sensor *sr)
350{
351 if (!try_module_get(module: sr->ops->owner))
352 return -ENODEV;
353 kref_get(kref: &sr->ref);
354 return 0;
355}
356EXPORT_SYMBOL_GPL(wf_get_sensor);
357
358void wf_put_sensor(struct wf_sensor *sr)
359{
360 struct module *mod = sr->ops->owner;
361 kref_put(kref: &sr->ref, release: wf_sensor_release);
362 module_put(module: mod);
363}
364EXPORT_SYMBOL_GPL(wf_put_sensor);
365
366
367/*
368 * Client & notification
369 */
370
371int 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(nh: &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, param: ct);
384 list_for_each_entry(sr, &wf_sensors, link)
385 wf_notify(WF_EVENT_NEW_SENSOR, param: sr);
386 if (wf_client_count == 1)
387 wf_start_thread();
388 bail:
389 mutex_unlock(lock: &wf_lock);
390 return rc;
391}
392EXPORT_SYMBOL_GPL(wf_register_client);
393
394int wf_unregister_client(struct notifier_block *nb)
395{
396 mutex_lock(&wf_lock);
397 blocking_notifier_chain_unregister(nh: &wf_client_list, nb);
398 wf_client_count--;
399 if (wf_client_count == 0)
400 wf_stop_thread();
401 mutex_unlock(lock: &wf_lock);
402
403 return 0;
404}
405EXPORT_SYMBOL_GPL(wf_unregister_client);
406
407void 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(lock: &wf_lock);
417}
418EXPORT_SYMBOL_GPL(wf_set_overtemp);
419
420void wf_clear_overtemp(void)
421{
422 mutex_lock(&wf_lock);
423 WARN_ON(wf_overtemp == 0);
424 if (wf_overtemp == 0) {
425 mutex_unlock(lock: &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(lock: &wf_lock);
434}
435EXPORT_SYMBOL_GPL(wf_clear_overtemp);
436
437static 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
445static 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
455module_init(windfarm_core_init);
456module_exit(windfarm_core_exit);
457
458MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
459MODULE_DESCRIPTION("Core component of PowerMac thermal control");
460MODULE_LICENSE("GPL");
461
462

source code of linux/drivers/macintosh/windfarm_core.c