1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * bios-less APM driver for ARM Linux |
4 | * Jamey Hicks <jamey@crl.dec.com> |
5 | * adapted from the APM BIOS driver for Linux by Stephen Rothwell (sfr@linuxcare.com) |
6 | * |
7 | * APM 1.2 Reference: |
8 | * Intel Corporation, Microsoft Corporation. Advanced Power Management |
9 | * (APM) BIOS Interface Specification, Revision 1.2, February 1996. |
10 | * |
11 | * This document is available from Microsoft at: |
12 | * http://www.microsoft.com/whdc/archive/amp_12.mspx |
13 | */ |
14 | #include <linux/module.h> |
15 | #include <linux/poll.h> |
16 | #include <linux/slab.h> |
17 | #include <linux/mutex.h> |
18 | #include <linux/proc_fs.h> |
19 | #include <linux/seq_file.h> |
20 | #include <linux/miscdevice.h> |
21 | #include <linux/apm_bios.h> |
22 | #include <linux/capability.h> |
23 | #include <linux/sched.h> |
24 | #include <linux/suspend.h> |
25 | #include <linux/apm-emulation.h> |
26 | #include <linux/freezer.h> |
27 | #include <linux/device.h> |
28 | #include <linux/kernel.h> |
29 | #include <linux/list.h> |
30 | #include <linux/init.h> |
31 | #include <linux/completion.h> |
32 | #include <linux/kthread.h> |
33 | #include <linux/delay.h> |
34 | |
35 | /* |
36 | * One option can be changed at boot time as follows: |
37 | * apm=on/off enable/disable APM |
38 | */ |
39 | |
40 | /* |
41 | * Maximum number of events stored |
42 | */ |
43 | #define APM_MAX_EVENTS 16 |
44 | |
45 | struct apm_queue { |
46 | unsigned int event_head; |
47 | unsigned int event_tail; |
48 | apm_event_t events[APM_MAX_EVENTS]; |
49 | }; |
50 | |
51 | /* |
52 | * thread states (for threads using a writable /dev/apm_bios fd): |
53 | * |
54 | * SUSPEND_NONE: nothing happening |
55 | * SUSPEND_PENDING: suspend event queued for thread and pending to be read |
56 | * SUSPEND_READ: suspend event read, pending acknowledgement |
57 | * SUSPEND_ACKED: acknowledgement received from thread (via ioctl), |
58 | * waiting for resume |
59 | * SUSPEND_ACKTO: acknowledgement timeout |
60 | * SUSPEND_DONE: thread had acked suspend and is now notified of |
61 | * resume |
62 | * |
63 | * SUSPEND_WAIT: this thread invoked suspend and is waiting for resume |
64 | * |
65 | * A thread migrates in one of three paths: |
66 | * NONE -1-> PENDING -2-> READ -3-> ACKED -4-> DONE -5-> NONE |
67 | * -6-> ACKTO -7-> NONE |
68 | * NONE -8-> WAIT -9-> NONE |
69 | * |
70 | * While in PENDING or READ, the thread is accounted for in the |
71 | * suspend_acks_pending counter. |
72 | * |
73 | * The transitions are invoked as follows: |
74 | * 1: suspend event is signalled from the core PM code |
75 | * 2: the suspend event is read from the fd by the userspace thread |
76 | * 3: userspace thread issues the APM_IOC_SUSPEND ioctl (as ack) |
77 | * 4: core PM code signals that we have resumed |
78 | * 5: APM_IOC_SUSPEND ioctl returns |
79 | * |
80 | * 6: the notifier invoked from the core PM code timed out waiting |
81 | * for all relevant threds to enter ACKED state and puts those |
82 | * that haven't into ACKTO |
83 | * 7: those threads issue APM_IOC_SUSPEND ioctl too late, |
84 | * get an error |
85 | * |
86 | * 8: userspace thread issues the APM_IOC_SUSPEND ioctl (to suspend), |
87 | * ioctl code invokes pm_suspend() |
88 | * 9: pm_suspend() returns indicating resume |
89 | */ |
90 | enum apm_suspend_state { |
91 | SUSPEND_NONE, |
92 | SUSPEND_PENDING, |
93 | SUSPEND_READ, |
94 | SUSPEND_ACKED, |
95 | SUSPEND_ACKTO, |
96 | SUSPEND_WAIT, |
97 | SUSPEND_DONE, |
98 | }; |
99 | |
100 | /* |
101 | * The per-file APM data |
102 | */ |
103 | struct apm_user { |
104 | struct list_head list; |
105 | |
106 | unsigned int suser: 1; |
107 | unsigned int writer: 1; |
108 | unsigned int reader: 1; |
109 | |
110 | int suspend_result; |
111 | enum apm_suspend_state suspend_state; |
112 | |
113 | struct apm_queue queue; |
114 | }; |
115 | |
116 | /* |
117 | * Local variables |
118 | */ |
119 | static atomic_t suspend_acks_pending = ATOMIC_INIT(0); |
120 | static atomic_t userspace_notification_inhibit = ATOMIC_INIT(0); |
121 | static int apm_disabled; |
122 | static struct task_struct *kapmd_tsk; |
123 | |
124 | static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue); |
125 | static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue); |
126 | |
127 | /* |
128 | * This is a list of everyone who has opened /dev/apm_bios |
129 | */ |
130 | static DECLARE_RWSEM(user_list_lock); |
131 | static LIST_HEAD(apm_user_list); |
132 | |
133 | /* |
134 | * kapmd info. kapmd provides us a process context to handle |
135 | * "APM" events within - specifically necessary if we're going |
136 | * to be suspending the system. |
137 | */ |
138 | static DECLARE_WAIT_QUEUE_HEAD(kapmd_wait); |
139 | static DEFINE_SPINLOCK(kapmd_queue_lock); |
140 | static struct apm_queue kapmd_queue; |
141 | |
142 | static DEFINE_MUTEX(state_lock); |
143 | |
144 | static const char driver_version[] = "1.13" ; /* no spaces */ |
145 | |
146 | |
147 | |
148 | /* |
149 | * Compatibility cruft until the IPAQ people move over to the new |
150 | * interface. |
151 | */ |
152 | static void __apm_get_power_status(struct apm_power_info *info) |
153 | { |
154 | } |
155 | |
156 | /* |
157 | * This allows machines to provide their own "apm get power status" function. |
158 | */ |
159 | void (*apm_get_power_status)(struct apm_power_info *) = __apm_get_power_status; |
160 | EXPORT_SYMBOL(apm_get_power_status); |
161 | |
162 | |
163 | /* |
164 | * APM event queue management. |
165 | */ |
166 | static inline int queue_empty(struct apm_queue *q) |
167 | { |
168 | return q->event_head == q->event_tail; |
169 | } |
170 | |
171 | static inline apm_event_t queue_get_event(struct apm_queue *q) |
172 | { |
173 | q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS; |
174 | return q->events[q->event_tail]; |
175 | } |
176 | |
177 | static void queue_add_event(struct apm_queue *q, apm_event_t event) |
178 | { |
179 | q->event_head = (q->event_head + 1) % APM_MAX_EVENTS; |
180 | if (q->event_head == q->event_tail) { |
181 | static int notified; |
182 | |
183 | if (notified++ == 0) |
184 | printk(KERN_ERR "apm: an event queue overflowed\n" ); |
185 | q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS; |
186 | } |
187 | q->events[q->event_head] = event; |
188 | } |
189 | |
190 | static void queue_event(apm_event_t event) |
191 | { |
192 | struct apm_user *as; |
193 | |
194 | down_read(sem: &user_list_lock); |
195 | list_for_each_entry(as, &apm_user_list, list) { |
196 | if (as->reader) |
197 | queue_add_event(q: &as->queue, event); |
198 | } |
199 | up_read(sem: &user_list_lock); |
200 | wake_up_interruptible(&apm_waitqueue); |
201 | } |
202 | |
203 | static ssize_t apm_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos) |
204 | { |
205 | struct apm_user *as = fp->private_data; |
206 | apm_event_t event; |
207 | int i = count, ret = 0; |
208 | |
209 | if (count < sizeof(apm_event_t)) |
210 | return -EINVAL; |
211 | |
212 | if (queue_empty(q: &as->queue) && fp->f_flags & O_NONBLOCK) |
213 | return -EAGAIN; |
214 | |
215 | wait_event_interruptible(apm_waitqueue, !queue_empty(&as->queue)); |
216 | |
217 | while ((i >= sizeof(event)) && !queue_empty(q: &as->queue)) { |
218 | event = queue_get_event(q: &as->queue); |
219 | |
220 | ret = -EFAULT; |
221 | if (copy_to_user(to: buf, from: &event, n: sizeof(event))) |
222 | break; |
223 | |
224 | mutex_lock(&state_lock); |
225 | if (as->suspend_state == SUSPEND_PENDING && |
226 | (event == APM_SYS_SUSPEND || event == APM_USER_SUSPEND)) |
227 | as->suspend_state = SUSPEND_READ; |
228 | mutex_unlock(lock: &state_lock); |
229 | |
230 | buf += sizeof(event); |
231 | i -= sizeof(event); |
232 | } |
233 | |
234 | if (i < count) |
235 | ret = count - i; |
236 | |
237 | return ret; |
238 | } |
239 | |
240 | static __poll_t apm_poll(struct file *fp, poll_table * wait) |
241 | { |
242 | struct apm_user *as = fp->private_data; |
243 | |
244 | poll_wait(filp: fp, wait_address: &apm_waitqueue, p: wait); |
245 | return queue_empty(q: &as->queue) ? 0 : EPOLLIN | EPOLLRDNORM; |
246 | } |
247 | |
248 | /* |
249 | * apm_ioctl - handle APM ioctl |
250 | * |
251 | * APM_IOC_SUSPEND |
252 | * This IOCTL is overloaded, and performs two functions. It is used to: |
253 | * - initiate a suspend |
254 | * - acknowledge a suspend read from /dev/apm_bios. |
255 | * Only when everyone who has opened /dev/apm_bios with write permission |
256 | * has acknowledge does the actual suspend happen. |
257 | */ |
258 | static long |
259 | apm_ioctl(struct file *filp, u_int cmd, u_long arg) |
260 | { |
261 | struct apm_user *as = filp->private_data; |
262 | int err = -EINVAL; |
263 | |
264 | if (!as->suser || !as->writer) |
265 | return -EPERM; |
266 | |
267 | switch (cmd) { |
268 | case APM_IOC_SUSPEND: |
269 | mutex_lock(&state_lock); |
270 | |
271 | as->suspend_result = -EINTR; |
272 | |
273 | switch (as->suspend_state) { |
274 | case SUSPEND_READ: |
275 | /* |
276 | * If we read a suspend command from /dev/apm_bios, |
277 | * then the corresponding APM_IOC_SUSPEND ioctl is |
278 | * interpreted as an acknowledge. |
279 | */ |
280 | as->suspend_state = SUSPEND_ACKED; |
281 | atomic_dec(v: &suspend_acks_pending); |
282 | mutex_unlock(lock: &state_lock); |
283 | |
284 | /* |
285 | * suspend_acks_pending changed, the notifier needs to |
286 | * be woken up for this |
287 | */ |
288 | wake_up(&apm_suspend_waitqueue); |
289 | |
290 | /* |
291 | * Wait for the suspend/resume to complete. If there |
292 | * are pending acknowledges, we wait here for them. |
293 | * wait_event_freezable() is interruptible and pending |
294 | * signal can cause busy looping. We aren't doing |
295 | * anything critical, chill a bit on each iteration. |
296 | */ |
297 | while (wait_event_freezable(apm_suspend_waitqueue, |
298 | as->suspend_state != SUSPEND_ACKED)) |
299 | msleep(msecs: 10); |
300 | break; |
301 | case SUSPEND_ACKTO: |
302 | as->suspend_result = -ETIMEDOUT; |
303 | mutex_unlock(lock: &state_lock); |
304 | break; |
305 | default: |
306 | as->suspend_state = SUSPEND_WAIT; |
307 | mutex_unlock(lock: &state_lock); |
308 | |
309 | /* |
310 | * Otherwise it is a request to suspend the system. |
311 | * Just invoke pm_suspend(), we'll handle it from |
312 | * there via the notifier. |
313 | */ |
314 | as->suspend_result = pm_suspend(PM_SUSPEND_MEM); |
315 | } |
316 | |
317 | mutex_lock(&state_lock); |
318 | err = as->suspend_result; |
319 | as->suspend_state = SUSPEND_NONE; |
320 | mutex_unlock(lock: &state_lock); |
321 | break; |
322 | } |
323 | |
324 | return err; |
325 | } |
326 | |
327 | static int apm_release(struct inode * inode, struct file * filp) |
328 | { |
329 | struct apm_user *as = filp->private_data; |
330 | |
331 | filp->private_data = NULL; |
332 | |
333 | down_write(sem: &user_list_lock); |
334 | list_del(entry: &as->list); |
335 | up_write(sem: &user_list_lock); |
336 | |
337 | /* |
338 | * We are now unhooked from the chain. As far as new |
339 | * events are concerned, we no longer exist. |
340 | */ |
341 | mutex_lock(&state_lock); |
342 | if (as->suspend_state == SUSPEND_PENDING || |
343 | as->suspend_state == SUSPEND_READ) |
344 | atomic_dec(v: &suspend_acks_pending); |
345 | mutex_unlock(lock: &state_lock); |
346 | |
347 | wake_up(&apm_suspend_waitqueue); |
348 | |
349 | kfree(objp: as); |
350 | return 0; |
351 | } |
352 | |
353 | static int apm_open(struct inode * inode, struct file * filp) |
354 | { |
355 | struct apm_user *as; |
356 | |
357 | as = kzalloc(size: sizeof(*as), GFP_KERNEL); |
358 | if (as) { |
359 | /* |
360 | * XXX - this is a tiny bit broken, when we consider BSD |
361 | * process accounting. If the device is opened by root, we |
362 | * instantly flag that we used superuser privs. Who knows, |
363 | * we might close the device immediately without doing a |
364 | * privileged operation -- cevans |
365 | */ |
366 | as->suser = capable(CAP_SYS_ADMIN); |
367 | as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE; |
368 | as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ; |
369 | |
370 | down_write(sem: &user_list_lock); |
371 | list_add(new: &as->list, head: &apm_user_list); |
372 | up_write(sem: &user_list_lock); |
373 | |
374 | filp->private_data = as; |
375 | } |
376 | |
377 | return as ? 0 : -ENOMEM; |
378 | } |
379 | |
380 | static const struct file_operations apm_bios_fops = { |
381 | .owner = THIS_MODULE, |
382 | .read = apm_read, |
383 | .poll = apm_poll, |
384 | .unlocked_ioctl = apm_ioctl, |
385 | .open = apm_open, |
386 | .release = apm_release, |
387 | .llseek = noop_llseek, |
388 | }; |
389 | |
390 | static struct miscdevice apm_device = { |
391 | .minor = APM_MINOR_DEV, |
392 | .name = "apm_bios" , |
393 | .fops = &apm_bios_fops |
394 | }; |
395 | |
396 | |
397 | #ifdef CONFIG_PROC_FS |
398 | /* |
399 | * Arguments, with symbols from linux/apm_bios.h. |
400 | * |
401 | * 0) Linux driver version (this will change if format changes) |
402 | * 1) APM BIOS Version. Usually 1.0, 1.1 or 1.2. |
403 | * 2) APM flags from APM Installation Check (0x00): |
404 | * bit 0: APM_16_BIT_SUPPORT |
405 | * bit 1: APM_32_BIT_SUPPORT |
406 | * bit 2: APM_IDLE_SLOWS_CLOCK |
407 | * bit 3: APM_BIOS_DISABLED |
408 | * bit 4: APM_BIOS_DISENGAGED |
409 | * 3) AC line status |
410 | * 0x00: Off-line |
411 | * 0x01: On-line |
412 | * 0x02: On backup power (BIOS >= 1.1 only) |
413 | * 0xff: Unknown |
414 | * 4) Battery status |
415 | * 0x00: High |
416 | * 0x01: Low |
417 | * 0x02: Critical |
418 | * 0x03: Charging |
419 | * 0x04: Selected battery not present (BIOS >= 1.2 only) |
420 | * 0xff: Unknown |
421 | * 5) Battery flag |
422 | * bit 0: High |
423 | * bit 1: Low |
424 | * bit 2: Critical |
425 | * bit 3: Charging |
426 | * bit 7: No system battery |
427 | * 0xff: Unknown |
428 | * 6) Remaining battery life (percentage of charge): |
429 | * 0-100: valid |
430 | * -1: Unknown |
431 | * 7) Remaining battery life (time units): |
432 | * Number of remaining minutes or seconds |
433 | * -1: Unknown |
434 | * 8) min = minutes; sec = seconds |
435 | */ |
436 | static int proc_apm_show(struct seq_file *m, void *v) |
437 | { |
438 | struct apm_power_info info; |
439 | char *units; |
440 | |
441 | info.ac_line_status = 0xff; |
442 | info.battery_status = 0xff; |
443 | info.battery_flag = 0xff; |
444 | info.battery_life = -1; |
445 | info.time = -1; |
446 | info.units = -1; |
447 | |
448 | if (apm_get_power_status) |
449 | apm_get_power_status(&info); |
450 | |
451 | switch (info.units) { |
452 | default: units = "?" ; break; |
453 | case 0: units = "min" ; break; |
454 | case 1: units = "sec" ; break; |
455 | } |
456 | |
457 | seq_printf(m, fmt: "%s 1.2 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n" , |
458 | driver_version, APM_32_BIT_SUPPORT, |
459 | info.ac_line_status, info.battery_status, |
460 | info.battery_flag, info.battery_life, |
461 | info.time, units); |
462 | |
463 | return 0; |
464 | } |
465 | #endif |
466 | |
467 | static int kapmd(void *arg) |
468 | { |
469 | do { |
470 | apm_event_t event; |
471 | |
472 | wait_event_interruptible(kapmd_wait, |
473 | !queue_empty(&kapmd_queue) || kthread_should_stop()); |
474 | |
475 | if (kthread_should_stop()) |
476 | break; |
477 | |
478 | spin_lock_irq(lock: &kapmd_queue_lock); |
479 | event = 0; |
480 | if (!queue_empty(q: &kapmd_queue)) |
481 | event = queue_get_event(q: &kapmd_queue); |
482 | spin_unlock_irq(lock: &kapmd_queue_lock); |
483 | |
484 | switch (event) { |
485 | case 0: |
486 | break; |
487 | |
488 | case APM_LOW_BATTERY: |
489 | case APM_POWER_STATUS_CHANGE: |
490 | queue_event(event); |
491 | break; |
492 | |
493 | case APM_USER_SUSPEND: |
494 | case APM_SYS_SUSPEND: |
495 | pm_suspend(PM_SUSPEND_MEM); |
496 | break; |
497 | |
498 | case APM_CRITICAL_SUSPEND: |
499 | atomic_inc(v: &userspace_notification_inhibit); |
500 | pm_suspend(PM_SUSPEND_MEM); |
501 | atomic_dec(v: &userspace_notification_inhibit); |
502 | break; |
503 | } |
504 | } while (1); |
505 | |
506 | return 0; |
507 | } |
508 | |
509 | static int apm_suspend_notifier(struct notifier_block *nb, |
510 | unsigned long event, |
511 | void *dummy) |
512 | { |
513 | struct apm_user *as; |
514 | int err; |
515 | unsigned long apm_event; |
516 | |
517 | /* short-cut emergency suspends */ |
518 | if (atomic_read(v: &userspace_notification_inhibit)) |
519 | return NOTIFY_DONE; |
520 | |
521 | switch (event) { |
522 | case PM_SUSPEND_PREPARE: |
523 | case PM_HIBERNATION_PREPARE: |
524 | apm_event = (event == PM_SUSPEND_PREPARE) ? |
525 | APM_USER_SUSPEND : APM_USER_HIBERNATION; |
526 | /* |
527 | * Queue an event to all "writer" users that we want |
528 | * to suspend and need their ack. |
529 | */ |
530 | mutex_lock(&state_lock); |
531 | down_read(sem: &user_list_lock); |
532 | |
533 | list_for_each_entry(as, &apm_user_list, list) { |
534 | if (as->suspend_state != SUSPEND_WAIT && as->reader && |
535 | as->writer && as->suser) { |
536 | as->suspend_state = SUSPEND_PENDING; |
537 | atomic_inc(v: &suspend_acks_pending); |
538 | queue_add_event(q: &as->queue, event: apm_event); |
539 | } |
540 | } |
541 | |
542 | up_read(sem: &user_list_lock); |
543 | mutex_unlock(lock: &state_lock); |
544 | wake_up_interruptible(&apm_waitqueue); |
545 | |
546 | /* |
547 | * Wait for the suspend_acks_pending variable to drop to |
548 | * zero, meaning everybody acked the suspend event (or the |
549 | * process was killed.) |
550 | * |
551 | * If the app won't answer within a short while we assume it |
552 | * locked up and ignore it. |
553 | */ |
554 | err = wait_event_interruptible_timeout( |
555 | apm_suspend_waitqueue, |
556 | atomic_read(&suspend_acks_pending) == 0, |
557 | 5*HZ); |
558 | |
559 | /* timed out */ |
560 | if (err == 0) { |
561 | /* |
562 | * Move anybody who timed out to "ack timeout" state. |
563 | * |
564 | * We could time out and the userspace does the ACK |
565 | * right after we time out but before we enter the |
566 | * locked section here, but that's fine. |
567 | */ |
568 | mutex_lock(&state_lock); |
569 | down_read(sem: &user_list_lock); |
570 | list_for_each_entry(as, &apm_user_list, list) { |
571 | if (as->suspend_state == SUSPEND_PENDING || |
572 | as->suspend_state == SUSPEND_READ) { |
573 | as->suspend_state = SUSPEND_ACKTO; |
574 | atomic_dec(v: &suspend_acks_pending); |
575 | } |
576 | } |
577 | up_read(sem: &user_list_lock); |
578 | mutex_unlock(lock: &state_lock); |
579 | } |
580 | |
581 | /* let suspend proceed */ |
582 | if (err >= 0) |
583 | return NOTIFY_OK; |
584 | |
585 | /* interrupted by signal */ |
586 | return notifier_from_errno(err); |
587 | |
588 | case PM_POST_SUSPEND: |
589 | case PM_POST_HIBERNATION: |
590 | apm_event = (event == PM_POST_SUSPEND) ? |
591 | APM_NORMAL_RESUME : APM_HIBERNATION_RESUME; |
592 | /* |
593 | * Anyone on the APM queues will think we're still suspended. |
594 | * Send a message so everyone knows we're now awake again. |
595 | */ |
596 | queue_event(event: apm_event); |
597 | |
598 | /* |
599 | * Finally, wake up anyone who is sleeping on the suspend. |
600 | */ |
601 | mutex_lock(&state_lock); |
602 | down_read(sem: &user_list_lock); |
603 | list_for_each_entry(as, &apm_user_list, list) { |
604 | if (as->suspend_state == SUSPEND_ACKED) { |
605 | /* |
606 | * TODO: maybe grab error code, needs core |
607 | * changes to push the error to the notifier |
608 | * chain (could use the second parameter if |
609 | * implemented) |
610 | */ |
611 | as->suspend_result = 0; |
612 | as->suspend_state = SUSPEND_DONE; |
613 | } |
614 | } |
615 | up_read(sem: &user_list_lock); |
616 | mutex_unlock(lock: &state_lock); |
617 | |
618 | wake_up(&apm_suspend_waitqueue); |
619 | return NOTIFY_OK; |
620 | |
621 | default: |
622 | return NOTIFY_DONE; |
623 | } |
624 | } |
625 | |
626 | static struct notifier_block apm_notif_block = { |
627 | .notifier_call = apm_suspend_notifier, |
628 | }; |
629 | |
630 | static int __init apm_init(void) |
631 | { |
632 | int ret; |
633 | |
634 | if (apm_disabled) { |
635 | printk(KERN_NOTICE "apm: disabled on user request.\n" ); |
636 | return -ENODEV; |
637 | } |
638 | |
639 | kapmd_tsk = kthread_create(kapmd, NULL, "kapmd" ); |
640 | if (IS_ERR(ptr: kapmd_tsk)) { |
641 | ret = PTR_ERR(ptr: kapmd_tsk); |
642 | kapmd_tsk = NULL; |
643 | goto out; |
644 | } |
645 | wake_up_process(tsk: kapmd_tsk); |
646 | |
647 | #ifdef CONFIG_PROC_FS |
648 | proc_create_single("apm" , 0, NULL, proc_apm_show); |
649 | #endif |
650 | |
651 | ret = misc_register(misc: &apm_device); |
652 | if (ret) |
653 | goto out_stop; |
654 | |
655 | ret = register_pm_notifier(nb: &apm_notif_block); |
656 | if (ret) |
657 | goto out_unregister; |
658 | |
659 | return 0; |
660 | |
661 | out_unregister: |
662 | misc_deregister(misc: &apm_device); |
663 | out_stop: |
664 | remove_proc_entry("apm" , NULL); |
665 | kthread_stop(k: kapmd_tsk); |
666 | out: |
667 | return ret; |
668 | } |
669 | |
670 | static void __exit apm_exit(void) |
671 | { |
672 | unregister_pm_notifier(nb: &apm_notif_block); |
673 | misc_deregister(misc: &apm_device); |
674 | remove_proc_entry("apm" , NULL); |
675 | |
676 | kthread_stop(k: kapmd_tsk); |
677 | } |
678 | |
679 | module_init(apm_init); |
680 | module_exit(apm_exit); |
681 | |
682 | MODULE_AUTHOR("Stephen Rothwell" ); |
683 | MODULE_DESCRIPTION("Advanced Power Management" ); |
684 | MODULE_LICENSE("GPL" ); |
685 | |
686 | #ifndef MODULE |
687 | static int __init apm_setup(char *str) |
688 | { |
689 | while ((str != NULL) && (*str != '\0')) { |
690 | if (strncmp(str, "off" , 3) == 0) |
691 | apm_disabled = 1; |
692 | if (strncmp(str, "on" , 2) == 0) |
693 | apm_disabled = 0; |
694 | str = strchr(str, ','); |
695 | if (str != NULL) |
696 | str += strspn(str, ", \t" ); |
697 | } |
698 | return 1; |
699 | } |
700 | |
701 | __setup("apm=" , apm_setup); |
702 | #endif |
703 | |
704 | /** |
705 | * apm_queue_event - queue an APM event for kapmd |
706 | * @event: APM event |
707 | * |
708 | * Queue an APM event for kapmd to process and ultimately take the |
709 | * appropriate action. Only a subset of events are handled: |
710 | * %APM_LOW_BATTERY |
711 | * %APM_POWER_STATUS_CHANGE |
712 | * %APM_USER_SUSPEND |
713 | * %APM_SYS_SUSPEND |
714 | * %APM_CRITICAL_SUSPEND |
715 | */ |
716 | void apm_queue_event(apm_event_t event) |
717 | { |
718 | unsigned long flags; |
719 | |
720 | spin_lock_irqsave(&kapmd_queue_lock, flags); |
721 | queue_add_event(q: &kapmd_queue, event); |
722 | spin_unlock_irqrestore(lock: &kapmd_queue_lock, flags); |
723 | |
724 | wake_up_interruptible(&kapmd_wait); |
725 | } |
726 | EXPORT_SYMBOL(apm_queue_event); |
727 | |