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1da177e4 LT |
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/config.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/poll.h> | |
16 | #include <linux/timer.h> | |
17 | #include <linux/slab.h> | |
18 | #include <linux/proc_fs.h> | |
19 | #include <linux/miscdevice.h> | |
20 | #include <linux/apm_bios.h> | |
a9415644 | 21 | #include <linux/capability.h> |
1da177e4 LT |
22 | #include <linux/sched.h> |
23 | #include <linux/pm.h> | |
24 | #include <linux/device.h> | |
25 | #include <linux/kernel.h> | |
26 | #include <linux/list.h> | |
27 | #include <linux/init.h> | |
28 | #include <linux/completion.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 | ||
52 | struct 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 | */ | |
61 | struct 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_DONE 4 /* suspend completed */ | |
75 | ||
76 | struct apm_queue queue; | |
77 | }; | |
78 | ||
79 | /* | |
80 | * Local variables | |
81 | */ | |
82 | static int suspends_pending; | |
83 | static int apm_disabled; | |
53b7c2b2 | 84 | static int arm_apm_active; |
1da177e4 LT |
85 | |
86 | static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue); | |
87 | static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue); | |
88 | ||
89 | /* | |
90 | * This is a list of everyone who has opened /dev/apm_bios | |
91 | */ | |
92 | static DECLARE_RWSEM(user_list_lock); | |
93 | static LIST_HEAD(apm_user_list); | |
94 | ||
95 | /* | |
96 | * kapmd info. kapmd provides us a process context to handle | |
97 | * "APM" events within - specifically necessary if we're going | |
98 | * to be suspending the system. | |
99 | */ | |
100 | static DECLARE_WAIT_QUEUE_HEAD(kapmd_wait); | |
101 | static DECLARE_COMPLETION(kapmd_exit); | |
102 | static DEFINE_SPINLOCK(kapmd_queue_lock); | |
103 | static struct apm_queue kapmd_queue; | |
104 | ||
105 | ||
106 | static const char driver_version[] = "1.13"; /* no spaces */ | |
107 | ||
108 | ||
109 | ||
110 | /* | |
111 | * Compatibility cruft until the IPAQ people move over to the new | |
112 | * interface. | |
113 | */ | |
114 | static void __apm_get_power_status(struct apm_power_info *info) | |
115 | { | |
116 | } | |
117 | ||
118 | /* | |
119 | * This allows machines to provide their own "apm get power status" function. | |
120 | */ | |
121 | void (*apm_get_power_status)(struct apm_power_info *) = __apm_get_power_status; | |
122 | EXPORT_SYMBOL(apm_get_power_status); | |
123 | ||
124 | ||
125 | /* | |
126 | * APM event queue management. | |
127 | */ | |
128 | static inline int queue_empty(struct apm_queue *q) | |
129 | { | |
130 | return q->event_head == q->event_tail; | |
131 | } | |
132 | ||
133 | static inline apm_event_t queue_get_event(struct apm_queue *q) | |
134 | { | |
135 | q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS; | |
136 | return q->events[q->event_tail]; | |
137 | } | |
138 | ||
139 | static void queue_add_event(struct apm_queue *q, apm_event_t event) | |
140 | { | |
141 | q->event_head = (q->event_head + 1) % APM_MAX_EVENTS; | |
142 | if (q->event_head == q->event_tail) { | |
143 | static int notified; | |
144 | ||
145 | if (notified++ == 0) | |
146 | printk(KERN_ERR "apm: an event queue overflowed\n"); | |
147 | q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS; | |
148 | } | |
149 | q->events[q->event_head] = event; | |
150 | } | |
151 | ||
152 | static void queue_event_one_user(struct apm_user *as, apm_event_t event) | |
153 | { | |
154 | if (as->suser && as->writer) { | |
155 | switch (event) { | |
156 | case APM_SYS_SUSPEND: | |
157 | case APM_USER_SUSPEND: | |
158 | /* | |
159 | * If this user already has a suspend pending, | |
160 | * don't queue another one. | |
161 | */ | |
162 | if (as->suspend_state != SUSPEND_NONE) | |
163 | return; | |
164 | ||
165 | as->suspend_state = SUSPEND_PENDING; | |
166 | suspends_pending++; | |
167 | break; | |
168 | } | |
169 | } | |
170 | queue_add_event(&as->queue, event); | |
171 | } | |
172 | ||
173 | static void queue_event(apm_event_t event, struct apm_user *sender) | |
174 | { | |
175 | struct apm_user *as; | |
176 | ||
177 | down_read(&user_list_lock); | |
178 | list_for_each_entry(as, &apm_user_list, list) { | |
179 | if (as != sender && as->reader) | |
180 | queue_event_one_user(as, event); | |
181 | } | |
182 | up_read(&user_list_lock); | |
183 | wake_up_interruptible(&apm_waitqueue); | |
184 | } | |
185 | ||
186 | static void apm_suspend(void) | |
187 | { | |
188 | struct apm_user *as; | |
189 | int err = pm_suspend(PM_SUSPEND_MEM); | |
190 | ||
191 | /* | |
192 | * Anyone on the APM queues will think we're still suspended. | |
193 | * Send a message so everyone knows we're now awake again. | |
194 | */ | |
195 | queue_event(APM_NORMAL_RESUME, NULL); | |
196 | ||
197 | /* | |
198 | * Finally, wake up anyone who is sleeping on the suspend. | |
199 | */ | |
200 | down_read(&user_list_lock); | |
201 | list_for_each_entry(as, &apm_user_list, list) { | |
202 | as->suspend_result = err; | |
203 | as->suspend_state = SUSPEND_DONE; | |
204 | } | |
205 | up_read(&user_list_lock); | |
206 | ||
207 | wake_up(&apm_suspend_waitqueue); | |
208 | } | |
209 | ||
210 | static ssize_t apm_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos) | |
211 | { | |
212 | struct apm_user *as = fp->private_data; | |
213 | apm_event_t event; | |
214 | int i = count, ret = 0; | |
215 | ||
216 | if (count < sizeof(apm_event_t)) | |
217 | return -EINVAL; | |
218 | ||
219 | if (queue_empty(&as->queue) && fp->f_flags & O_NONBLOCK) | |
220 | return -EAGAIN; | |
221 | ||
222 | wait_event_interruptible(apm_waitqueue, !queue_empty(&as->queue)); | |
223 | ||
224 | while ((i >= sizeof(event)) && !queue_empty(&as->queue)) { | |
225 | event = queue_get_event(&as->queue); | |
226 | ||
227 | ret = -EFAULT; | |
228 | if (copy_to_user(buf, &event, sizeof(event))) | |
229 | break; | |
230 | ||
231 | if (event == APM_SYS_SUSPEND || event == APM_USER_SUSPEND) | |
232 | as->suspend_state = SUSPEND_READ; | |
233 | ||
234 | buf += sizeof(event); | |
235 | i -= sizeof(event); | |
236 | } | |
237 | ||
238 | if (i < count) | |
239 | ret = count - i; | |
240 | ||
241 | return ret; | |
242 | } | |
243 | ||
244 | static unsigned int apm_poll(struct file *fp, poll_table * wait) | |
245 | { | |
246 | struct apm_user *as = fp->private_data; | |
247 | ||
248 | poll_wait(fp, &apm_waitqueue, wait); | |
249 | return queue_empty(&as->queue) ? 0 : POLLIN | POLLRDNORM; | |
250 | } | |
251 | ||
252 | /* | |
253 | * apm_ioctl - handle APM ioctl | |
254 | * | |
255 | * APM_IOC_SUSPEND | |
256 | * This IOCTL is overloaded, and performs two functions. It is used to: | |
257 | * - initiate a suspend | |
258 | * - acknowledge a suspend read from /dev/apm_bios. | |
259 | * Only when everyone who has opened /dev/apm_bios with write permission | |
260 | * has acknowledge does the actual suspend happen. | |
261 | */ | |
262 | static int | |
263 | apm_ioctl(struct inode * inode, struct file *filp, u_int cmd, u_long arg) | |
264 | { | |
265 | struct apm_user *as = filp->private_data; | |
266 | unsigned long flags; | |
267 | int err = -EINVAL; | |
268 | ||
269 | if (!as->suser || !as->writer) | |
270 | return -EPERM; | |
271 | ||
272 | switch (cmd) { | |
273 | case APM_IOC_SUSPEND: | |
274 | as->suspend_result = -EINTR; | |
275 | ||
276 | if (as->suspend_state == SUSPEND_READ) { | |
277 | /* | |
278 | * If we read a suspend command from /dev/apm_bios, | |
279 | * then the corresponding APM_IOC_SUSPEND ioctl is | |
280 | * interpreted as an acknowledge. | |
281 | */ | |
282 | as->suspend_state = SUSPEND_ACKED; | |
283 | suspends_pending--; | |
284 | } else { | |
285 | /* | |
286 | * Otherwise it is a request to suspend the system. | |
287 | * Queue an event for all readers, and expect an | |
288 | * acknowledge from all writers who haven't already | |
289 | * acknowledged. | |
290 | */ | |
291 | queue_event(APM_USER_SUSPEND, as); | |
292 | } | |
293 | ||
294 | /* | |
295 | * If there are no further acknowledges required, suspend | |
296 | * the system. | |
297 | */ | |
298 | if (suspends_pending == 0) | |
299 | apm_suspend(); | |
300 | ||
301 | /* | |
302 | * Wait for the suspend/resume to complete. If there are | |
303 | * pending acknowledges, we wait here for them. | |
304 | * | |
305 | * Note that we need to ensure that the PM subsystem does | |
306 | * not kick us out of the wait when it suspends the threads. | |
307 | */ | |
308 | flags = current->flags; | |
309 | current->flags |= PF_NOFREEZE; | |
310 | ||
311 | /* | |
312 | * Note: do not allow a thread which is acking the suspend | |
313 | * to escape until the resume is complete. | |
314 | */ | |
315 | if (as->suspend_state == SUSPEND_ACKED) | |
316 | wait_event(apm_suspend_waitqueue, | |
317 | as->suspend_state == SUSPEND_DONE); | |
318 | else | |
319 | wait_event_interruptible(apm_suspend_waitqueue, | |
320 | as->suspend_state == SUSPEND_DONE); | |
321 | ||
322 | current->flags = flags; | |
323 | err = as->suspend_result; | |
324 | as->suspend_state = SUSPEND_NONE; | |
325 | break; | |
326 | } | |
327 | ||
328 | return err; | |
329 | } | |
330 | ||
331 | static int apm_release(struct inode * inode, struct file * filp) | |
332 | { | |
333 | struct apm_user *as = filp->private_data; | |
334 | filp->private_data = NULL; | |
335 | ||
336 | down_write(&user_list_lock); | |
337 | list_del(&as->list); | |
338 | up_write(&user_list_lock); | |
339 | ||
340 | /* | |
341 | * We are now unhooked from the chain. As far as new | |
342 | * events are concerned, we no longer exist. However, we | |
343 | * need to balance suspends_pending, which means the | |
344 | * possibility of sleeping. | |
345 | */ | |
346 | if (as->suspend_state != SUSPEND_NONE) { | |
347 | suspends_pending -= 1; | |
348 | if (suspends_pending == 0) | |
349 | apm_suspend(); | |
350 | } | |
351 | ||
352 | kfree(as); | |
353 | return 0; | |
354 | } | |
355 | ||
356 | static int apm_open(struct inode * inode, struct file * filp) | |
357 | { | |
358 | struct apm_user *as; | |
359 | ||
360 | as = (struct apm_user *)kmalloc(sizeof(*as), GFP_KERNEL); | |
361 | if (as) { | |
362 | memset(as, 0, sizeof(*as)); | |
363 | ||
364 | /* | |
365 | * XXX - this is a tiny bit broken, when we consider BSD | |
366 | * process accounting. If the device is opened by root, we | |
367 | * instantly flag that we used superuser privs. Who knows, | |
368 | * we might close the device immediately without doing a | |
369 | * privileged operation -- cevans | |
370 | */ | |
371 | as->suser = capable(CAP_SYS_ADMIN); | |
372 | as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE; | |
373 | as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ; | |
374 | ||
375 | down_write(&user_list_lock); | |
376 | list_add(&as->list, &apm_user_list); | |
377 | up_write(&user_list_lock); | |
378 | ||
379 | filp->private_data = as; | |
380 | } | |
381 | ||
382 | return as ? 0 : -ENOMEM; | |
383 | } | |
384 | ||
385 | static struct file_operations apm_bios_fops = { | |
386 | .owner = THIS_MODULE, | |
387 | .read = apm_read, | |
388 | .poll = apm_poll, | |
389 | .ioctl = apm_ioctl, | |
390 | .open = apm_open, | |
391 | .release = apm_release, | |
392 | }; | |
393 | ||
394 | static struct miscdevice apm_device = { | |
395 | .minor = APM_MINOR_DEV, | |
396 | .name = "apm_bios", | |
397 | .fops = &apm_bios_fops | |
398 | }; | |
399 | ||
400 | ||
401 | #ifdef CONFIG_PROC_FS | |
402 | /* | |
403 | * Arguments, with symbols from linux/apm_bios.h. | |
404 | * | |
405 | * 0) Linux driver version (this will change if format changes) | |
406 | * 1) APM BIOS Version. Usually 1.0, 1.1 or 1.2. | |
407 | * 2) APM flags from APM Installation Check (0x00): | |
408 | * bit 0: APM_16_BIT_SUPPORT | |
409 | * bit 1: APM_32_BIT_SUPPORT | |
410 | * bit 2: APM_IDLE_SLOWS_CLOCK | |
411 | * bit 3: APM_BIOS_DISABLED | |
412 | * bit 4: APM_BIOS_DISENGAGED | |
413 | * 3) AC line status | |
414 | * 0x00: Off-line | |
415 | * 0x01: On-line | |
416 | * 0x02: On backup power (BIOS >= 1.1 only) | |
417 | * 0xff: Unknown | |
418 | * 4) Battery status | |
419 | * 0x00: High | |
420 | * 0x01: Low | |
421 | * 0x02: Critical | |
422 | * 0x03: Charging | |
423 | * 0x04: Selected battery not present (BIOS >= 1.2 only) | |
424 | * 0xff: Unknown | |
425 | * 5) Battery flag | |
426 | * bit 0: High | |
427 | * bit 1: Low | |
428 | * bit 2: Critical | |
429 | * bit 3: Charging | |
430 | * bit 7: No system battery | |
431 | * 0xff: Unknown | |
432 | * 6) Remaining battery life (percentage of charge): | |
433 | * 0-100: valid | |
434 | * -1: Unknown | |
435 | * 7) Remaining battery life (time units): | |
436 | * Number of remaining minutes or seconds | |
437 | * -1: Unknown | |
438 | * 8) min = minutes; sec = seconds | |
439 | */ | |
440 | static int apm_get_info(char *buf, char **start, off_t fpos, int length) | |
441 | { | |
442 | struct apm_power_info info; | |
443 | char *units; | |
444 | int ret; | |
445 | ||
446 | info.ac_line_status = 0xff; | |
447 | info.battery_status = 0xff; | |
448 | info.battery_flag = 0xff; | |
449 | info.battery_life = -1; | |
450 | info.time = -1; | |
451 | info.units = -1; | |
452 | ||
453 | if (apm_get_power_status) | |
454 | apm_get_power_status(&info); | |
455 | ||
456 | switch (info.units) { | |
457 | default: units = "?"; break; | |
458 | case 0: units = "min"; break; | |
459 | case 1: units = "sec"; break; | |
460 | } | |
461 | ||
462 | ret = sprintf(buf, "%s 1.2 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n", | |
463 | driver_version, APM_32_BIT_SUPPORT, | |
464 | info.ac_line_status, info.battery_status, | |
465 | info.battery_flag, info.battery_life, | |
466 | info.time, units); | |
467 | ||
468 | return ret; | |
469 | } | |
470 | #endif | |
471 | ||
472 | static int kapmd(void *arg) | |
473 | { | |
474 | daemonize("kapmd"); | |
475 | current->flags |= PF_NOFREEZE; | |
476 | ||
477 | do { | |
478 | apm_event_t event; | |
479 | ||
480 | wait_event_interruptible(kapmd_wait, | |
53b7c2b2 | 481 | !queue_empty(&kapmd_queue) || !arm_apm_active); |
1da177e4 | 482 | |
53b7c2b2 | 483 | if (!arm_apm_active) |
1da177e4 LT |
484 | break; |
485 | ||
486 | spin_lock_irq(&kapmd_queue_lock); | |
487 | event = 0; | |
488 | if (!queue_empty(&kapmd_queue)) | |
489 | event = queue_get_event(&kapmd_queue); | |
490 | spin_unlock_irq(&kapmd_queue_lock); | |
491 | ||
492 | switch (event) { | |
493 | case 0: | |
494 | break; | |
495 | ||
496 | case APM_LOW_BATTERY: | |
497 | case APM_POWER_STATUS_CHANGE: | |
498 | queue_event(event, NULL); | |
499 | break; | |
500 | ||
501 | case APM_USER_SUSPEND: | |
502 | case APM_SYS_SUSPEND: | |
503 | queue_event(event, NULL); | |
504 | if (suspends_pending == 0) | |
505 | apm_suspend(); | |
506 | break; | |
507 | ||
508 | case APM_CRITICAL_SUSPEND: | |
509 | apm_suspend(); | |
510 | break; | |
511 | } | |
512 | } while (1); | |
513 | ||
514 | complete_and_exit(&kapmd_exit, 0); | |
515 | } | |
516 | ||
517 | static int __init apm_init(void) | |
518 | { | |
519 | int ret; | |
520 | ||
521 | if (apm_disabled) { | |
522 | printk(KERN_NOTICE "apm: disabled on user request.\n"); | |
523 | return -ENODEV; | |
524 | } | |
525 | ||
53b7c2b2 | 526 | arm_apm_active = 1; |
1da177e4 LT |
527 | |
528 | ret = kernel_thread(kapmd, NULL, CLONE_KERNEL); | |
529 | if (ret < 0) { | |
53b7c2b2 | 530 | arm_apm_active = 0; |
1da177e4 LT |
531 | return ret; |
532 | } | |
533 | ||
534 | #ifdef CONFIG_PROC_FS | |
535 | create_proc_info_entry("apm", 0, NULL, apm_get_info); | |
536 | #endif | |
537 | ||
538 | ret = misc_register(&apm_device); | |
539 | if (ret != 0) { | |
540 | remove_proc_entry("apm", NULL); | |
541 | ||
53b7c2b2 | 542 | arm_apm_active = 0; |
1da177e4 LT |
543 | wake_up(&kapmd_wait); |
544 | wait_for_completion(&kapmd_exit); | |
545 | } | |
546 | ||
547 | return ret; | |
548 | } | |
549 | ||
550 | static void __exit apm_exit(void) | |
551 | { | |
552 | misc_deregister(&apm_device); | |
553 | remove_proc_entry("apm", NULL); | |
554 | ||
53b7c2b2 | 555 | arm_apm_active = 0; |
1da177e4 LT |
556 | wake_up(&kapmd_wait); |
557 | wait_for_completion(&kapmd_exit); | |
558 | } | |
559 | ||
560 | module_init(apm_init); | |
561 | module_exit(apm_exit); | |
562 | ||
563 | MODULE_AUTHOR("Stephen Rothwell"); | |
564 | MODULE_DESCRIPTION("Advanced Power Management"); | |
565 | MODULE_LICENSE("GPL"); | |
566 | ||
567 | #ifndef MODULE | |
568 | static int __init apm_setup(char *str) | |
569 | { | |
570 | while ((str != NULL) && (*str != '\0')) { | |
571 | if (strncmp(str, "off", 3) == 0) | |
572 | apm_disabled = 1; | |
573 | if (strncmp(str, "on", 2) == 0) | |
574 | apm_disabled = 0; | |
575 | str = strchr(str, ','); | |
576 | if (str != NULL) | |
577 | str += strspn(str, ", \t"); | |
578 | } | |
579 | return 1; | |
580 | } | |
581 | ||
582 | __setup("apm=", apm_setup); | |
583 | #endif | |
584 | ||
585 | /** | |
586 | * apm_queue_event - queue an APM event for kapmd | |
587 | * @event: APM event | |
588 | * | |
589 | * Queue an APM event for kapmd to process and ultimately take the | |
590 | * appropriate action. Only a subset of events are handled: | |
591 | * %APM_LOW_BATTERY | |
592 | * %APM_POWER_STATUS_CHANGE | |
593 | * %APM_USER_SUSPEND | |
594 | * %APM_SYS_SUSPEND | |
595 | * %APM_CRITICAL_SUSPEND | |
596 | */ | |
597 | void apm_queue_event(apm_event_t event) | |
598 | { | |
599 | unsigned long flags; | |
600 | ||
601 | spin_lock_irqsave(&kapmd_queue_lock, flags); | |
602 | queue_add_event(&kapmd_queue, event); | |
603 | spin_unlock_irqrestore(&kapmd_queue_lock, flags); | |
604 | ||
605 | wake_up_interruptible(&kapmd_wait); | |
606 | } | |
607 | EXPORT_SYMBOL(apm_queue_event); |