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-rw-r--r--arch/arm/kernel/apm.c672
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diff --git a/arch/arm/kernel/apm.c b/arch/arm/kernel/apm.c
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--- a/arch/arm/kernel/apm.c
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1/*
2 * bios-less APM driver for ARM Linux
3 * Jamey Hicks <jamey@crl.dec.com>
4 * adapted from the APM BIOS driver for Linux by Stephen Rothwell (sfr@linuxcare.com)
5 *
6 * APM 1.2 Reference:
7 * Intel Corporation, Microsoft Corporation. Advanced Power Management
8 * (APM) BIOS Interface Specification, Revision 1.2, February 1996.
9 *
10 * [This document is available from Microsoft at:
11 * http://www.microsoft.com/hwdev/busbios/amp_12.htm]
12 */
13#include <linux/module.h>
14#include <linux/poll.h>
15#include <linux/slab.h>
16#include <linux/proc_fs.h>
17#include <linux/miscdevice.h>
18#include <linux/apm_bios.h>
19#include <linux/capability.h>
20#include <linux/sched.h>
21#include <linux/pm.h>
22#include <linux/device.h>
23#include <linux/kernel.h>
24#include <linux/list.h>
25#include <linux/init.h>
26#include <linux/completion.h>
27#include <linux/kthread.h>
28#include <linux/delay.h>
29
30#include <asm/apm.h> /* apm_power_info */
31#include <asm/system.h>
32
33/*
34 * The apm_bios device is one of the misc char devices.
35 * This is its minor number.
36 */
37#define APM_MINOR_DEV 134
38
39/*
40 * See Documentation/Config.help for the configuration options.
41 *
42 * Various options can be changed at boot time as follows:
43 * (We allow underscores for compatibility with the modules code)
44 * apm=on/off enable/disable APM
45 */
46
47/*
48 * Maximum number of events stored
49 */
50#define APM_MAX_EVENTS 16
51
52struct apm_queue {
53 unsigned int event_head;
54 unsigned int event_tail;
55 apm_event_t events[APM_MAX_EVENTS];
56};
57
58/*
59 * The per-file APM data
60 */
61struct apm_user {
62 struct list_head list;
63
64 unsigned int suser: 1;
65 unsigned int writer: 1;
66 unsigned int reader: 1;
67
68 int suspend_result;
69 unsigned int suspend_state;
70#define SUSPEND_NONE 0 /* no suspend pending */
71#define SUSPEND_PENDING 1 /* suspend pending read */
72#define SUSPEND_READ 2 /* suspend read, pending ack */
73#define SUSPEND_ACKED 3 /* suspend acked */
74#define SUSPEND_WAIT 4 /* waiting for suspend */
75#define SUSPEND_DONE 5 /* suspend completed */
76
77 struct apm_queue queue;
78};
79
80/*
81 * Local variables
82 */
83static int suspends_pending;
84static int apm_disabled;
85static struct task_struct *kapmd_tsk;
86
87static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
88static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
89
90/*
91 * This is a list of everyone who has opened /dev/apm_bios
92 */
93static DECLARE_RWSEM(user_list_lock);
94static LIST_HEAD(apm_user_list);
95
96/*
97 * kapmd info. kapmd provides us a process context to handle
98 * "APM" events within - specifically necessary if we're going
99 * to be suspending the system.
100 */
101static DECLARE_WAIT_QUEUE_HEAD(kapmd_wait);
102static DEFINE_SPINLOCK(kapmd_queue_lock);
103static struct apm_queue kapmd_queue;
104
105static DEFINE_MUTEX(state_lock);
106
107static const char driver_version[] = "1.13"; /* no spaces */
108
109
110
111/*
112 * Compatibility cruft until the IPAQ people move over to the new
113 * interface.
114 */
115static void __apm_get_power_status(struct apm_power_info *info)
116{
117}
118
119/*
120 * This allows machines to provide their own "apm get power status" function.
121 */
122void (*apm_get_power_status)(struct apm_power_info *) = __apm_get_power_status;
123EXPORT_SYMBOL(apm_get_power_status);
124
125
126/*
127 * APM event queue management.
128 */
129static inline int queue_empty(struct apm_queue *q)
130{
131 return q->event_head == q->event_tail;
132}
133
134static inline apm_event_t queue_get_event(struct apm_queue *q)
135{
136 q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
137 return q->events[q->event_tail];
138}
139
140static void queue_add_event(struct apm_queue *q, apm_event_t event)
141{
142 q->event_head = (q->event_head + 1) % APM_MAX_EVENTS;
143 if (q->event_head == q->event_tail) {
144 static int notified;
145
146 if (notified++ == 0)
147 printk(KERN_ERR "apm: an event queue overflowed\n");
148 q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
149 }
150 q->events[q->event_head] = event;
151}
152
153static void queue_event(apm_event_t event)
154{
155 struct apm_user *as;
156
157 down_read(&user_list_lock);
158 list_for_each_entry(as, &apm_user_list, list) {
159 if (as->reader)
160 queue_add_event(&as->queue, event);
161 }
162 up_read(&user_list_lock);
163 wake_up_interruptible(&apm_waitqueue);
164}
165
166/*
167 * queue_suspend_event - queue an APM suspend event.
168 *
169 * Check that we're in a state where we can suspend. If not,
170 * return -EBUSY. Otherwise, queue an event to all "writer"
171 * users. If there are no "writer" users, return '1' to
172 * indicate that we can immediately suspend.
173 */
174static int queue_suspend_event(apm_event_t event, struct apm_user *sender)
175{
176 struct apm_user *as;
177 int ret = 1;
178
179 mutex_lock(&state_lock);
180 down_read(&user_list_lock);
181
182 /*
183 * If a thread is still processing, we can't suspend, so reject
184 * the request.
185 */
186 list_for_each_entry(as, &apm_user_list, list) {
187 if (as != sender && as->reader && as->writer && as->suser &&
188 as->suspend_state != SUSPEND_NONE) {
189 ret = -EBUSY;
190 goto out;
191 }
192 }
193
194 list_for_each_entry(as, &apm_user_list, list) {
195 if (as != sender && as->reader && as->writer && as->suser) {
196 as->suspend_state = SUSPEND_PENDING;
197 suspends_pending++;
198 queue_add_event(&as->queue, event);
199 ret = 0;
200 }
201 }
202 out:
203 up_read(&user_list_lock);
204 mutex_unlock(&state_lock);
205 wake_up_interruptible(&apm_waitqueue);
206 return ret;
207}
208
209static void apm_suspend(void)
210{
211 struct apm_user *as;
212 int err = pm_suspend(PM_SUSPEND_MEM);
213
214 /*
215 * Anyone on the APM queues will think we're still suspended.
216 * Send a message so everyone knows we're now awake again.
217 */
218 queue_event(APM_NORMAL_RESUME);
219
220 /*
221 * Finally, wake up anyone who is sleeping on the suspend.
222 */
223 mutex_lock(&state_lock);
224 down_read(&user_list_lock);
225 list_for_each_entry(as, &apm_user_list, list) {
226 if (as->suspend_state == SUSPEND_WAIT ||
227 as->suspend_state == SUSPEND_ACKED) {
228 as->suspend_result = err;
229 as->suspend_state = SUSPEND_DONE;
230 }
231 }
232 up_read(&user_list_lock);
233 mutex_unlock(&state_lock);
234
235 wake_up(&apm_suspend_waitqueue);
236}
237
238static ssize_t apm_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
239{
240 struct apm_user *as = fp->private_data;
241 apm_event_t event;
242 int i = count, ret = 0;
243
244 if (count < sizeof(apm_event_t))
245 return -EINVAL;
246
247 if (queue_empty(&as->queue) && fp->f_flags & O_NONBLOCK)
248 return -EAGAIN;
249
250 wait_event_interruptible(apm_waitqueue, !queue_empty(&as->queue));
251
252 while ((i >= sizeof(event)) && !queue_empty(&as->queue)) {
253 event = queue_get_event(&as->queue);
254
255 ret = -EFAULT;
256 if (copy_to_user(buf, &event, sizeof(event)))
257 break;
258
259 mutex_lock(&state_lock);
260 if (as->suspend_state == SUSPEND_PENDING &&
261 (event == APM_SYS_SUSPEND || event == APM_USER_SUSPEND))
262 as->suspend_state = SUSPEND_READ;
263 mutex_unlock(&state_lock);
264
265 buf += sizeof(event);
266 i -= sizeof(event);
267 }
268
269 if (i < count)
270 ret = count - i;
271
272 return ret;
273}
274
275static unsigned int apm_poll(struct file *fp, poll_table * wait)
276{
277 struct apm_user *as = fp->private_data;
278
279 poll_wait(fp, &apm_waitqueue, wait);
280 return queue_empty(&as->queue) ? 0 : POLLIN | POLLRDNORM;
281}
282
283/*
284 * apm_ioctl - handle APM ioctl
285 *
286 * APM_IOC_SUSPEND
287 * This IOCTL is overloaded, and performs two functions. It is used to:
288 * - initiate a suspend
289 * - acknowledge a suspend read from /dev/apm_bios.
290 * Only when everyone who has opened /dev/apm_bios with write permission
291 * has acknowledge does the actual suspend happen.
292 */
293static int
294apm_ioctl(struct inode * inode, struct file *filp, u_int cmd, u_long arg)
295{
296 struct apm_user *as = filp->private_data;
297 unsigned long flags;
298 int err = -EINVAL;
299
300 if (!as->suser || !as->writer)
301 return -EPERM;
302
303 switch (cmd) {
304 case APM_IOC_SUSPEND:
305 mutex_lock(&state_lock);
306
307 as->suspend_result = -EINTR;
308
309 if (as->suspend_state == SUSPEND_READ) {
310 int pending;
311
312 /*
313 * If we read a suspend command from /dev/apm_bios,
314 * then the corresponding APM_IOC_SUSPEND ioctl is
315 * interpreted as an acknowledge.
316 */
317 as->suspend_state = SUSPEND_ACKED;
318 suspends_pending--;
319 pending = suspends_pending == 0;
320 mutex_unlock(&state_lock);
321
322 /*
323 * If there are no further acknowledges required,
324 * suspend the system.
325 */
326 if (pending)
327 apm_suspend();
328
329 /*
330 * Wait for the suspend/resume to complete. If there
331 * are pending acknowledges, we wait here for them.
332 *
333 * Note: we need to ensure that the PM subsystem does
334 * not kick us out of the wait when it suspends the
335 * threads.
336 */
337 flags = current->flags;
338 current->flags |= PF_NOFREEZE;
339
340 wait_event(apm_suspend_waitqueue,
341 as->suspend_state == SUSPEND_DONE);
342 } else {
343 as->suspend_state = SUSPEND_WAIT;
344 mutex_unlock(&state_lock);
345
346 /*
347 * Otherwise it is a request to suspend the system.
348 * Queue an event for all readers, and expect an
349 * acknowledge from all writers who haven't already
350 * acknowledged.
351 */
352 err = queue_suspend_event(APM_USER_SUSPEND, as);
353 if (err < 0) {
354 /*
355 * Avoid taking the lock here - this
356 * should be fine.
357 */
358 as->suspend_state = SUSPEND_NONE;
359 break;
360 }
361
362 if (err > 0)
363 apm_suspend();
364
365 /*
366 * Wait for the suspend/resume to complete. If there
367 * are pending acknowledges, we wait here for them.
368 *
369 * Note: we need to ensure that the PM subsystem does
370 * not kick us out of the wait when it suspends the
371 * threads.
372 */
373 flags = current->flags;
374 current->flags |= PF_NOFREEZE;
375
376 wait_event_interruptible(apm_suspend_waitqueue,
377 as->suspend_state == SUSPEND_DONE);
378 }
379
380 current->flags = flags;
381
382 mutex_lock(&state_lock);
383 err = as->suspend_result;
384 as->suspend_state = SUSPEND_NONE;
385 mutex_unlock(&state_lock);
386 break;
387 }
388
389 return err;
390}
391
392static int apm_release(struct inode * inode, struct file * filp)
393{
394 struct apm_user *as = filp->private_data;
395 int pending = 0;
396
397 filp->private_data = NULL;
398
399 down_write(&user_list_lock);
400 list_del(&as->list);
401 up_write(&user_list_lock);
402
403 /*
404 * We are now unhooked from the chain. As far as new
405 * events are concerned, we no longer exist. However, we
406 * need to balance suspends_pending, which means the
407 * possibility of sleeping.
408 */
409 mutex_lock(&state_lock);
410 if (as->suspend_state != SUSPEND_NONE) {
411 suspends_pending -= 1;
412 pending = suspends_pending == 0;
413 }
414 mutex_unlock(&state_lock);
415 if (pending)
416 apm_suspend();
417
418 kfree(as);
419 return 0;
420}
421
422static int apm_open(struct inode * inode, struct file * filp)
423{
424 struct apm_user *as;
425
426 as = kzalloc(sizeof(*as), GFP_KERNEL);
427 if (as) {
428 /*
429 * XXX - this is a tiny bit broken, when we consider BSD
430 * process accounting. If the device is opened by root, we
431 * instantly flag that we used superuser privs. Who knows,
432 * we might close the device immediately without doing a
433 * privileged operation -- cevans
434 */
435 as->suser = capable(CAP_SYS_ADMIN);
436 as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
437 as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
438
439 down_write(&user_list_lock);
440 list_add(&as->list, &apm_user_list);
441 up_write(&user_list_lock);
442
443 filp->private_data = as;
444 }
445
446 return as ? 0 : -ENOMEM;
447}
448
449static struct file_operations apm_bios_fops = {
450 .owner = THIS_MODULE,
451 .read = apm_read,
452 .poll = apm_poll,
453 .ioctl = apm_ioctl,
454 .open = apm_open,
455 .release = apm_release,
456};
457
458static struct miscdevice apm_device = {
459 .minor = APM_MINOR_DEV,
460 .name = "apm_bios",
461 .fops = &apm_bios_fops
462};
463
464
465#ifdef CONFIG_PROC_FS
466/*
467 * Arguments, with symbols from linux/apm_bios.h.
468 *
469 * 0) Linux driver version (this will change if format changes)
470 * 1) APM BIOS Version. Usually 1.0, 1.1 or 1.2.
471 * 2) APM flags from APM Installation Check (0x00):
472 * bit 0: APM_16_BIT_SUPPORT
473 * bit 1: APM_32_BIT_SUPPORT
474 * bit 2: APM_IDLE_SLOWS_CLOCK
475 * bit 3: APM_BIOS_DISABLED
476 * bit 4: APM_BIOS_DISENGAGED
477 * 3) AC line status
478 * 0x00: Off-line
479 * 0x01: On-line
480 * 0x02: On backup power (BIOS >= 1.1 only)
481 * 0xff: Unknown
482 * 4) Battery status
483 * 0x00: High
484 * 0x01: Low
485 * 0x02: Critical
486 * 0x03: Charging
487 * 0x04: Selected battery not present (BIOS >= 1.2 only)
488 * 0xff: Unknown
489 * 5) Battery flag
490 * bit 0: High
491 * bit 1: Low
492 * bit 2: Critical
493 * bit 3: Charging
494 * bit 7: No system battery
495 * 0xff: Unknown
496 * 6) Remaining battery life (percentage of charge):
497 * 0-100: valid
498 * -1: Unknown
499 * 7) Remaining battery life (time units):
500 * Number of remaining minutes or seconds
501 * -1: Unknown
502 * 8) min = minutes; sec = seconds
503 */
504static int apm_get_info(char *buf, char **start, off_t fpos, int length)
505{
506 struct apm_power_info info;
507 char *units;
508 int ret;
509
510 info.ac_line_status = 0xff;
511 info.battery_status = 0xff;
512 info.battery_flag = 0xff;
513 info.battery_life = -1;
514 info.time = -1;
515 info.units = -1;
516
517 if (apm_get_power_status)
518 apm_get_power_status(&info);
519
520 switch (info.units) {
521 default: units = "?"; break;
522 case 0: units = "min"; break;
523 case 1: units = "sec"; break;
524 }
525
526 ret = sprintf(buf, "%s 1.2 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
527 driver_version, APM_32_BIT_SUPPORT,
528 info.ac_line_status, info.battery_status,
529 info.battery_flag, info.battery_life,
530 info.time, units);
531
532 return ret;
533}
534#endif
535
536static int kapmd(void *arg)
537{
538 do {
539 apm_event_t event;
540 int ret;
541
542 wait_event_interruptible(kapmd_wait,
543 !queue_empty(&kapmd_queue) || kthread_should_stop());
544
545 if (kthread_should_stop())
546 break;
547
548 spin_lock_irq(&kapmd_queue_lock);
549 event = 0;
550 if (!queue_empty(&kapmd_queue))
551 event = queue_get_event(&kapmd_queue);
552 spin_unlock_irq(&kapmd_queue_lock);
553
554 switch (event) {
555 case 0:
556 break;
557
558 case APM_LOW_BATTERY:
559 case APM_POWER_STATUS_CHANGE:
560 queue_event(event);
561 break;
562
563 case APM_USER_SUSPEND:
564 case APM_SYS_SUSPEND:
565 ret = queue_suspend_event(event, NULL);
566 if (ret < 0) {
567 /*
568 * We were busy. Try again in 50ms.
569 */
570 queue_add_event(&kapmd_queue, event);
571 msleep(50);
572 }
573 if (ret > 0)
574 apm_suspend();
575 break;
576
577 case APM_CRITICAL_SUSPEND:
578 apm_suspend();
579 break;
580 }
581 } while (1);
582
583 return 0;
584}
585
586static int __init apm_init(void)
587{
588 int ret;
589
590 if (apm_disabled) {
591 printk(KERN_NOTICE "apm: disabled on user request.\n");
592 return -ENODEV;
593 }
594
595 kapmd_tsk = kthread_create(kapmd, NULL, "kapmd");
596 if (IS_ERR(kapmd_tsk)) {
597 ret = PTR_ERR(kapmd_tsk);
598 kapmd_tsk = NULL;
599 return ret;
600 }
601 kapmd_tsk->flags |= PF_NOFREEZE;
602 wake_up_process(kapmd_tsk);
603
604#ifdef CONFIG_PROC_FS
605 create_proc_info_entry("apm", 0, NULL, apm_get_info);
606#endif
607
608 ret = misc_register(&apm_device);
609 if (ret != 0) {
610 remove_proc_entry("apm", NULL);
611 kthread_stop(kapmd_tsk);
612 }
613
614 return ret;
615}
616
617static void __exit apm_exit(void)
618{
619 misc_deregister(&apm_device);
620 remove_proc_entry("apm", NULL);
621
622 kthread_stop(kapmd_tsk);
623}
624
625module_init(apm_init);
626module_exit(apm_exit);
627
628MODULE_AUTHOR("Stephen Rothwell");
629MODULE_DESCRIPTION("Advanced Power Management");
630MODULE_LICENSE("GPL");
631
632#ifndef MODULE
633static int __init apm_setup(char *str)
634{
635 while ((str != NULL) && (*str != '\0')) {
636 if (strncmp(str, "off", 3) == 0)
637 apm_disabled = 1;
638 if (strncmp(str, "on", 2) == 0)
639 apm_disabled = 0;
640 str = strchr(str, ',');
641 if (str != NULL)
642 str += strspn(str, ", \t");
643 }
644 return 1;
645}
646
647__setup("apm=", apm_setup);
648#endif
649
650/**
651 * apm_queue_event - queue an APM event for kapmd
652 * @event: APM event
653 *
654 * Queue an APM event for kapmd to process and ultimately take the
655 * appropriate action. Only a subset of events are handled:
656 * %APM_LOW_BATTERY
657 * %APM_POWER_STATUS_CHANGE
658 * %APM_USER_SUSPEND
659 * %APM_SYS_SUSPEND
660 * %APM_CRITICAL_SUSPEND
661 */
662void apm_queue_event(apm_event_t event)
663{
664 unsigned long flags;
665
666 spin_lock_irqsave(&kapmd_queue_lock, flags);
667 queue_add_event(&kapmd_queue, event);
668 spin_unlock_irqrestore(&kapmd_queue_lock, flags);
669
670 wake_up_interruptible(&kapmd_wait);
671}
672EXPORT_SYMBOL(apm_queue_event);
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