1 // SPDX-License-Identifier: GPL-2.0-only
3 * Windfarm PowerMac thermal control. Core
5 * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
6 * <benh@kernel.crashing.org>
8 * This core code tracks the list of sensors & controls, register
9 * clients, and holds the kernel thread used for control.
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
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
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>
45 #define DBG(args...) printk(args)
47 #define DBG(args...) do { } while(0)
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;
59 static struct platform_device wf_platform_device = {
64 * Utilities & tick thread
67 static inline void wf_notify(int event, void *param)
69 blocking_notifier_call_chain(&wf_client_list, event, param);
72 static int wf_critical_overtemp(void)
74 static char const critical_overtemp_path[] = "/sbin/critical_overtemp";
75 char *argv[] = { (char *)critical_overtemp_path, NULL };
76 static char *envp[] = { "HOME=/",
78 "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
81 return call_usermodehelper(critical_overtemp_path,
82 argv, envp, UMH_WAIT_EXEC);
85 static int wf_thread_func(void *data)
87 unsigned long next, delay;
91 DBG("wf: thread started\n");
94 while (!kthread_should_stop()) {
97 if (time_after_eq(jiffies, next)) {
98 wf_notify(WF_EVENT_TICK, NULL);
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 "
108 " seconds, shutting down\n");
115 delay = next - jiffies;
117 schedule_timeout_interruptible(delay);
120 DBG("wf: thread stopped\n");
125 static void wf_start_thread(void)
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",
136 static void wf_stop_thread(void)
139 kthread_stop(wf_thread);
147 static void wf_control_release(struct kref *kref)
149 struct wf_control *ct = container_of(kref, struct wf_control, ref);
151 DBG("wf: Deleting control %s\n", ct->name);
153 if (ct->ops && ct->ops->release)
154 ct->ops->release(ct);
159 static ssize_t wf_show_control(struct device *dev,
160 struct device_attribute *attr, char *buf)
162 struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
167 err = ctrl->ops->get_value(ctrl, &val);
170 return sprintf(buf, "<HW FAULT>\n");
174 case WF_CONTROL_RPM_FAN:
177 case WF_CONTROL_PWM_FAN:
183 return sprintf(buf, "%d%s\n", val, typestr);
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)
191 struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
196 val = simple_strtoul(buf, &endp, 0);
197 while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
199 if (endp - buf < count)
201 err = ctrl->ops->set_value(ctrl, val);
207 int wf_register_control(struct wf_control *new_ct)
209 struct wf_control *ct;
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);
220 kref_init(&new_ct->ref);
221 list_add(&new_ct->link, &wf_controls);
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 */
233 DBG("wf: Registered control %s\n", new_ct->name);
235 wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
236 mutex_unlock(&wf_lock);
240 EXPORT_SYMBOL_GPL(wf_register_control);
242 void wf_unregister_control(struct wf_control *ct)
244 mutex_lock(&wf_lock);
246 mutex_unlock(&wf_lock);
248 DBG("wf: Unregistered control %s\n", ct->name);
250 kref_put(&ct->ref, wf_control_release);
252 EXPORT_SYMBOL_GPL(wf_unregister_control);
254 int wf_get_control(struct wf_control *ct)
256 if (!try_module_get(ct->ops->owner))
261 EXPORT_SYMBOL_GPL(wf_get_control);
263 void wf_put_control(struct wf_control *ct)
265 struct module *mod = ct->ops->owner;
266 kref_put(&ct->ref, wf_control_release);
269 EXPORT_SYMBOL_GPL(wf_put_control);
277 static void wf_sensor_release(struct kref *kref)
279 struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);
281 DBG("wf: Deleting sensor %s\n", sr->name);
283 if (sr->ops && sr->ops->release)
284 sr->ops->release(sr);
289 static ssize_t wf_show_sensor(struct device *dev,
290 struct device_attribute *attr, char *buf)
292 struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
296 err = sens->ops->get_value(sens, &val);
299 return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
302 int wf_register_sensor(struct wf_sensor *new_sr)
304 struct wf_sensor *sr;
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);
315 kref_init(&new_sr->ref);
316 list_add(&new_sr->link, &wf_sensors);
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 */
328 DBG("wf: Registered sensor %s\n", new_sr->name);
330 wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
331 mutex_unlock(&wf_lock);
335 EXPORT_SYMBOL_GPL(wf_register_sensor);
337 void wf_unregister_sensor(struct wf_sensor *sr)
339 mutex_lock(&wf_lock);
341 mutex_unlock(&wf_lock);
343 DBG("wf: Unregistered sensor %s\n", sr->name);
347 EXPORT_SYMBOL_GPL(wf_unregister_sensor);
349 int wf_get_sensor(struct wf_sensor *sr)
351 if (!try_module_get(sr->ops->owner))
356 EXPORT_SYMBOL_GPL(wf_get_sensor);
358 void wf_put_sensor(struct wf_sensor *sr)
360 struct module *mod = sr->ops->owner;
361 kref_put(&sr->ref, wf_sensor_release);
364 EXPORT_SYMBOL_GPL(wf_put_sensor);
368 * Client & notification
371 int wf_register_client(struct notifier_block *nb)
374 struct wf_control *ct;
375 struct wf_sensor *sr;
377 mutex_lock(&wf_lock);
378 rc = blocking_notifier_chain_register(&wf_client_list, nb);
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)
389 mutex_unlock(&wf_lock);
392 EXPORT_SYMBOL_GPL(wf_register_client);
394 int wf_unregister_client(struct notifier_block *nb)
396 mutex_lock(&wf_lock);
397 blocking_notifier_chain_unregister(&wf_client_list, nb);
399 if (wf_client_count == 0)
401 mutex_unlock(&wf_lock);
405 EXPORT_SYMBOL_GPL(wf_unregister_client);
407 void wf_set_overtemp(void)
409 mutex_lock(&wf_lock);
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);
416 mutex_unlock(&wf_lock);
418 EXPORT_SYMBOL_GPL(wf_set_overtemp);
420 void wf_clear_overtemp(void)
422 mutex_lock(&wf_lock);
423 WARN_ON(wf_overtemp == 0);
424 if (wf_overtemp == 0) {
425 mutex_unlock(&wf_lock);
429 if (wf_overtemp == 0) {
430 printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
431 wf_notify(WF_EVENT_NORMALTEMP, NULL);
433 mutex_unlock(&wf_lock);
435 EXPORT_SYMBOL_GPL(wf_clear_overtemp);
437 static int __init windfarm_core_init(void)
439 DBG("wf: core loaded\n");
441 platform_device_register(&wf_platform_device);
445 static void __exit windfarm_core_exit(void)
447 BUG_ON(wf_client_count != 0);
449 DBG("wf: core unloaded\n");
451 platform_device_unregister(&wf_platform_device);
455 module_init(windfarm_core_init);
456 module_exit(windfarm_core_exit);
458 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
459 MODULE_DESCRIPTION("Core component of PowerMac thermal control");
460 MODULE_LICENSE("GPL");