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952fa954 RG |
1 | /* |
2 | * bios-less APM driver for MIPS 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 | */ | |
952fa954 RG |
13 | #include <linux/module.h> |
14 | #include <linux/poll.h> | |
15 | #include <linux/timer.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/proc_fs.h> | |
18 | #include <linux/miscdevice.h> | |
19 | #include <linux/apm_bios.h> | |
20 | #include <linux/capability.h> | |
21 | #include <linux/sched.h> | |
22 | #include <linux/pm.h> | |
23 | #include <linux/device.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/list.h> | |
26 | #include <linux/init.h> | |
27 | #include <linux/completion.h> | |
28 | ||
29 | #include <asm/apm.h> /* apm_power_info */ | |
30 | #include <asm/system.h> | |
31 | ||
32 | /* | |
33 | * The apm_bios device is one of the misc char devices. | |
34 | * This is its minor number. | |
35 | */ | |
36 | #define APM_MINOR_DEV 134 | |
37 | ||
38 | /* | |
39 | * See Documentation/Config.help for the configuration options. | |
40 | * | |
41 | * Various options can be changed at boot time as follows: | |
42 | * (We allow underscores for compatibility with the modules code) | |
43 | * apm=on/off enable/disable APM | |
44 | */ | |
45 | ||
46 | /* | |
47 | * Maximum number of events stored | |
48 | */ | |
49 | #define APM_MAX_EVENTS 16 | |
50 | ||
51 | struct apm_queue { | |
52 | unsigned int event_head; | |
53 | unsigned int event_tail; | |
54 | apm_event_t events[APM_MAX_EVENTS]; | |
55 | }; | |
56 | ||
57 | /* | |
58 | * The per-file APM data | |
59 | */ | |
60 | struct apm_user { | |
61 | struct list_head list; | |
62 | ||
63 | unsigned int suser: 1; | |
64 | unsigned int writer: 1; | |
65 | unsigned int reader: 1; | |
66 | ||
67 | int suspend_result; | |
68 | unsigned int suspend_state; | |
69 | #define SUSPEND_NONE 0 /* no suspend pending */ | |
70 | #define SUSPEND_PENDING 1 /* suspend pending read */ | |
71 | #define SUSPEND_READ 2 /* suspend read, pending ack */ | |
72 | #define SUSPEND_ACKED 3 /* suspend acked */ | |
73 | #define SUSPEND_DONE 4 /* suspend completed */ | |
74 | ||
75 | struct apm_queue queue; | |
76 | }; | |
77 | ||
78 | /* | |
79 | * Local variables | |
80 | */ | |
81 | static int suspends_pending; | |
82 | static int apm_disabled; | |
83 | static int mips_apm_active; | |
84 | ||
85 | static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue); | |
86 | static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue); | |
87 | ||
88 | /* | |
89 | * This is a list of everyone who has opened /dev/apm_bios | |
90 | */ | |
91 | static DECLARE_RWSEM(user_list_lock); | |
92 | static LIST_HEAD(apm_user_list); | |
93 | ||
94 | /* | |
95 | * kapmd info. kapmd provides us a process context to handle | |
96 | * "APM" events within - specifically necessary if we're going | |
97 | * to be suspending the system. | |
98 | */ | |
99 | static DECLARE_WAIT_QUEUE_HEAD(kapmd_wait); | |
100 | static DECLARE_COMPLETION(kapmd_exit); | |
101 | static DEFINE_SPINLOCK(kapmd_queue_lock); | |
102 | static struct apm_queue kapmd_queue; | |
103 | ||
104 | ||
105 | static const char driver_version[] = "1.13"; /* no spaces */ | |
106 | ||
107 | ||
108 | ||
109 | /* | |
110 | * Compatibility cruft until the IPAQ people move over to the new | |
111 | * interface. | |
112 | */ | |
113 | static void __apm_get_power_status(struct apm_power_info *info) | |
114 | { | |
115 | } | |
116 | ||
117 | /* | |
118 | * This allows machines to provide their own "apm get power status" function. | |
119 | */ | |
120 | void (*apm_get_power_status)(struct apm_power_info *) = __apm_get_power_status; | |
121 | EXPORT_SYMBOL(apm_get_power_status); | |
122 | ||
123 | ||
124 | /* | |
125 | * APM event queue management. | |
126 | */ | |
127 | static inline int queue_empty(struct apm_queue *q) | |
128 | { | |
129 | return q->event_head == q->event_tail; | |
130 | } | |
131 | ||
132 | static inline apm_event_t queue_get_event(struct apm_queue *q) | |
133 | { | |
134 | q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS; | |
135 | return q->events[q->event_tail]; | |
136 | } | |
137 | ||
138 | static void queue_add_event(struct apm_queue *q, apm_event_t event) | |
139 | { | |
140 | q->event_head = (q->event_head + 1) % APM_MAX_EVENTS; | |
141 | if (q->event_head == q->event_tail) { | |
142 | static int notified; | |
143 | ||
144 | if (notified++ == 0) | |
145 | printk(KERN_ERR "apm: an event queue overflowed\n"); | |
146 | q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS; | |
147 | } | |
148 | q->events[q->event_head] = event; | |
149 | } | |
150 | ||
151 | static void queue_event_one_user(struct apm_user *as, apm_event_t event) | |
152 | { | |
153 | if (as->suser && as->writer) { | |
154 | switch (event) { | |
155 | case APM_SYS_SUSPEND: | |
156 | case APM_USER_SUSPEND: | |
157 | /* | |
158 | * If this user already has a suspend pending, | |
159 | * don't queue another one. | |
160 | */ | |
161 | if (as->suspend_state != SUSPEND_NONE) | |
162 | return; | |
163 | ||
164 | as->suspend_state = SUSPEND_PENDING; | |
165 | suspends_pending++; | |
166 | break; | |
167 | } | |
168 | } | |
169 | queue_add_event(&as->queue, event); | |
170 | } | |
171 | ||
172 | static void queue_event(apm_event_t event, struct apm_user *sender) | |
173 | { | |
174 | struct apm_user *as; | |
175 | ||
176 | down_read(&user_list_lock); | |
177 | list_for_each_entry(as, &apm_user_list, list) { | |
178 | if (as != sender && as->reader) | |
179 | queue_event_one_user(as, event); | |
180 | } | |
181 | up_read(&user_list_lock); | |
182 | wake_up_interruptible(&apm_waitqueue); | |
183 | } | |
184 | ||
185 | static void apm_suspend(void) | |
186 | { | |
187 | struct apm_user *as; | |
188 | int err = pm_suspend(PM_SUSPEND_MEM); | |
189 | ||
190 | /* | |
191 | * Anyone on the APM queues will think we're still suspended. | |
192 | * Send a message so everyone knows we're now awake again. | |
193 | */ | |
194 | queue_event(APM_NORMAL_RESUME, NULL); | |
195 | ||
196 | /* | |
197 | * Finally, wake up anyone who is sleeping on the suspend. | |
198 | */ | |
199 | down_read(&user_list_lock); | |
200 | list_for_each_entry(as, &apm_user_list, list) { | |
201 | as->suspend_result = err; | |
202 | as->suspend_state = SUSPEND_DONE; | |
203 | } | |
204 | up_read(&user_list_lock); | |
205 | ||
206 | wake_up(&apm_suspend_waitqueue); | |
207 | } | |
208 | ||
209 | static ssize_t apm_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos) | |
210 | { | |
211 | struct apm_user *as = fp->private_data; | |
212 | apm_event_t event; | |
213 | int i = count, ret = 0; | |
214 | ||
215 | if (count < sizeof(apm_event_t)) | |
216 | return -EINVAL; | |
217 | ||
218 | if (queue_empty(&as->queue) && fp->f_flags & O_NONBLOCK) | |
219 | return -EAGAIN; | |
220 | ||
221 | wait_event_interruptible(apm_waitqueue, !queue_empty(&as->queue)); | |
222 | ||
223 | while ((i >= sizeof(event)) && !queue_empty(&as->queue)) { | |
224 | event = queue_get_event(&as->queue); | |
225 | ||
226 | ret = -EFAULT; | |
227 | if (copy_to_user(buf, &event, sizeof(event))) | |
228 | break; | |
229 | ||
230 | if (event == APM_SYS_SUSPEND || event == APM_USER_SUSPEND) | |
231 | as->suspend_state = SUSPEND_READ; | |
232 | ||
233 | buf += sizeof(event); | |
234 | i -= sizeof(event); | |
235 | } | |
236 | ||
237 | if (i < count) | |
238 | ret = count - i; | |
239 | ||
240 | return ret; | |
241 | } | |
242 | ||
243 | static unsigned int apm_poll(struct file *fp, poll_table * wait) | |
244 | { | |
245 | struct apm_user *as = fp->private_data; | |
246 | ||
247 | poll_wait(fp, &apm_waitqueue, wait); | |
248 | return queue_empty(&as->queue) ? 0 : POLLIN | POLLRDNORM; | |
249 | } | |
250 | ||
251 | /* | |
252 | * apm_ioctl - handle APM ioctl | |
253 | * | |
254 | * APM_IOC_SUSPEND | |
255 | * This IOCTL is overloaded, and performs two functions. It is used to: | |
256 | * - initiate a suspend | |
257 | * - acknowledge a suspend read from /dev/apm_bios. | |
258 | * Only when everyone who has opened /dev/apm_bios with write permission | |
259 | * has acknowledge does the actual suspend happen. | |
260 | */ | |
261 | static int | |
fc103349 | 262 | apm_ioctl(struct inode * inode, struct file *filp, unsigned int cmd, unsigned long arg) |
952fa954 RG |
263 | { |
264 | struct apm_user *as = filp->private_data; | |
265 | unsigned long flags; | |
266 | int err = -EINVAL; | |
267 | ||
268 | if (!as->suser || !as->writer) | |
269 | return -EPERM; | |
270 | ||
271 | switch (cmd) { | |
272 | case APM_IOC_SUSPEND: | |
273 | as->suspend_result = -EINTR; | |
274 | ||
275 | if (as->suspend_state == SUSPEND_READ) { | |
276 | /* | |
277 | * If we read a suspend command from /dev/apm_bios, | |
278 | * then the corresponding APM_IOC_SUSPEND ioctl is | |
279 | * interpreted as an acknowledge. | |
280 | */ | |
281 | as->suspend_state = SUSPEND_ACKED; | |
282 | suspends_pending--; | |
283 | } else { | |
284 | /* | |
285 | * Otherwise it is a request to suspend the system. | |
286 | * Queue an event for all readers, and expect an | |
287 | * acknowledge from all writers who haven't already | |
288 | * acknowledged. | |
289 | */ | |
290 | queue_event(APM_USER_SUSPEND, as); | |
291 | } | |
292 | ||
293 | /* | |
294 | * If there are no further acknowledges required, suspend | |
295 | * the system. | |
296 | */ | |
297 | if (suspends_pending == 0) | |
298 | apm_suspend(); | |
299 | ||
300 | /* | |
301 | * Wait for the suspend/resume to complete. If there are | |
302 | * pending acknowledges, we wait here for them. | |
303 | * | |
304 | * Note that we need to ensure that the PM subsystem does | |
305 | * not kick us out of the wait when it suspends the threads. | |
306 | */ | |
307 | flags = current->flags; | |
308 | current->flags |= PF_NOFREEZE; | |
309 | ||
310 | /* | |
311 | * Note: do not allow a thread which is acking the suspend | |
312 | * to escape until the resume is complete. | |
313 | */ | |
314 | if (as->suspend_state == SUSPEND_ACKED) | |
315 | wait_event(apm_suspend_waitqueue, | |
316 | as->suspend_state == SUSPEND_DONE); | |
317 | else | |
318 | wait_event_interruptible(apm_suspend_waitqueue, | |
319 | as->suspend_state == SUSPEND_DONE); | |
320 | ||
321 | current->flags = flags; | |
322 | err = as->suspend_result; | |
323 | as->suspend_state = SUSPEND_NONE; | |
324 | break; | |
325 | } | |
326 | ||
327 | return err; | |
328 | } | |
329 | ||
330 | static int apm_release(struct inode * inode, struct file * filp) | |
331 | { | |
332 | struct apm_user *as = filp->private_data; | |
333 | filp->private_data = NULL; | |
334 | ||
335 | down_write(&user_list_lock); | |
336 | list_del(&as->list); | |
337 | up_write(&user_list_lock); | |
338 | ||
339 | /* | |
340 | * We are now unhooked from the chain. As far as new | |
341 | * events are concerned, we no longer exist. However, we | |
342 | * need to balance suspends_pending, which means the | |
343 | * possibility of sleeping. | |
344 | */ | |
345 | if (as->suspend_state != SUSPEND_NONE) { | |
346 | suspends_pending -= 1; | |
347 | if (suspends_pending == 0) | |
348 | apm_suspend(); | |
349 | } | |
350 | ||
351 | kfree(as); | |
352 | return 0; | |
353 | } | |
354 | ||
355 | static int apm_open(struct inode * inode, struct file * filp) | |
356 | { | |
357 | struct apm_user *as; | |
358 | ||
5cbded58 | 359 | as = kzalloc(sizeof(*as), GFP_KERNEL); |
952fa954 RG |
360 | if (as) { |
361 | /* | |
362 | * XXX - this is a tiny bit broken, when we consider BSD | |
363 | * process accounting. If the device is opened by root, we | |
364 | * instantly flag that we used superuser privs. Who knows, | |
365 | * we might close the device immediately without doing a | |
366 | * privileged operation -- cevans | |
367 | */ | |
368 | as->suser = capable(CAP_SYS_ADMIN); | |
369 | as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE; | |
370 | as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ; | |
371 | ||
372 | down_write(&user_list_lock); | |
373 | list_add(&as->list, &apm_user_list); | |
374 | up_write(&user_list_lock); | |
375 | ||
376 | filp->private_data = as; | |
377 | } | |
378 | ||
379 | return as ? 0 : -ENOMEM; | |
380 | } | |
381 | ||
382 | static struct file_operations apm_bios_fops = { | |
383 | .owner = THIS_MODULE, | |
384 | .read = apm_read, | |
385 | .poll = apm_poll, | |
386 | .ioctl = apm_ioctl, | |
387 | .open = apm_open, | |
388 | .release = apm_release, | |
389 | }; | |
390 | ||
391 | static struct miscdevice apm_device = { | |
392 | .minor = APM_MINOR_DEV, | |
393 | .name = "apm_bios", | |
394 | .fops = &apm_bios_fops | |
395 | }; | |
396 | ||
397 | ||
398 | #ifdef CONFIG_PROC_FS | |
399 | /* | |
400 | * Arguments, with symbols from linux/apm_bios.h. | |
401 | * | |
402 | * 0) Linux driver version (this will change if format changes) | |
403 | * 1) APM BIOS Version. Usually 1.0, 1.1 or 1.2. | |
404 | * 2) APM flags from APM Installation Check (0x00): | |
405 | * bit 0: APM_16_BIT_SUPPORT | |
406 | * bit 1: APM_32_BIT_SUPPORT | |
407 | * bit 2: APM_IDLE_SLOWS_CLOCK | |
408 | * bit 3: APM_BIOS_DISABLED | |
409 | * bit 4: APM_BIOS_DISENGAGED | |
410 | * 3) AC line status | |
411 | * 0x00: Off-line | |
412 | * 0x01: On-line | |
413 | * 0x02: On backup power (BIOS >= 1.1 only) | |
414 | * 0xff: Unknown | |
415 | * 4) Battery status | |
416 | * 0x00: High | |
417 | * 0x01: Low | |
418 | * 0x02: Critical | |
419 | * 0x03: Charging | |
420 | * 0x04: Selected battery not present (BIOS >= 1.2 only) | |
421 | * 0xff: Unknown | |
422 | * 5) Battery flag | |
423 | * bit 0: High | |
424 | * bit 1: Low | |
425 | * bit 2: Critical | |
426 | * bit 3: Charging | |
427 | * bit 7: No system battery | |
428 | * 0xff: Unknown | |
429 | * 6) Remaining battery life (percentage of charge): | |
430 | * 0-100: valid | |
431 | * -1: Unknown | |
432 | * 7) Remaining battery life (time units): | |
433 | * Number of remaining minutes or seconds | |
434 | * -1: Unknown | |
435 | * 8) min = minutes; sec = seconds | |
436 | */ | |
437 | static int apm_get_info(char *buf, char **start, off_t fpos, int length) | |
438 | { | |
439 | struct apm_power_info info; | |
440 | char *units; | |
441 | int ret; | |
442 | ||
443 | info.ac_line_status = 0xff; | |
444 | info.battery_status = 0xff; | |
445 | info.battery_flag = 0xff; | |
446 | info.battery_life = -1; | |
447 | info.time = -1; | |
448 | info.units = -1; | |
449 | ||
450 | if (apm_get_power_status) | |
451 | apm_get_power_status(&info); | |
452 | ||
453 | switch (info.units) { | |
454 | default: units = "?"; break; | |
455 | case 0: units = "min"; break; | |
456 | case 1: units = "sec"; break; | |
457 | } | |
458 | ||
459 | ret = sprintf(buf, "%s 1.2 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n", | |
460 | driver_version, APM_32_BIT_SUPPORT, | |
461 | info.ac_line_status, info.battery_status, | |
462 | info.battery_flag, info.battery_life, | |
463 | info.time, units); | |
464 | ||
465 | return ret; | |
466 | } | |
467 | #endif | |
468 | ||
469 | static int kapmd(void *arg) | |
470 | { | |
471 | daemonize("kapmd"); | |
472 | current->flags |= PF_NOFREEZE; | |
473 | ||
474 | do { | |
475 | apm_event_t event; | |
476 | ||
477 | wait_event_interruptible(kapmd_wait, | |
478 | !queue_empty(&kapmd_queue) || !mips_apm_active); | |
479 | ||
480 | if (!mips_apm_active) | |
481 | break; | |
482 | ||
483 | spin_lock_irq(&kapmd_queue_lock); | |
484 | event = 0; | |
485 | if (!queue_empty(&kapmd_queue)) | |
486 | event = queue_get_event(&kapmd_queue); | |
487 | spin_unlock_irq(&kapmd_queue_lock); | |
488 | ||
489 | switch (event) { | |
490 | case 0: | |
491 | break; | |
492 | ||
493 | case APM_LOW_BATTERY: | |
494 | case APM_POWER_STATUS_CHANGE: | |
495 | queue_event(event, NULL); | |
496 | break; | |
497 | ||
498 | case APM_USER_SUSPEND: | |
499 | case APM_SYS_SUSPEND: | |
500 | queue_event(event, NULL); | |
501 | if (suspends_pending == 0) | |
502 | apm_suspend(); | |
503 | break; | |
504 | ||
505 | case APM_CRITICAL_SUSPEND: | |
506 | apm_suspend(); | |
507 | break; | |
508 | } | |
509 | } while (1); | |
510 | ||
511 | complete_and_exit(&kapmd_exit, 0); | |
512 | } | |
513 | ||
514 | static int __init apm_init(void) | |
515 | { | |
516 | int ret; | |
517 | ||
518 | if (apm_disabled) { | |
519 | printk(KERN_NOTICE "apm: disabled on user request.\n"); | |
520 | return -ENODEV; | |
521 | } | |
522 | ||
523 | mips_apm_active = 1; | |
524 | ||
525 | ret = kernel_thread(kapmd, NULL, CLONE_KERNEL); | |
526 | if (ret < 0) { | |
527 | mips_apm_active = 0; | |
528 | return ret; | |
529 | } | |
530 | ||
531 | #ifdef CONFIG_PROC_FS | |
532 | create_proc_info_entry("apm", 0, NULL, apm_get_info); | |
533 | #endif | |
534 | ||
535 | ret = misc_register(&apm_device); | |
536 | if (ret != 0) { | |
537 | remove_proc_entry("apm", NULL); | |
538 | ||
539 | mips_apm_active = 0; | |
540 | wake_up(&kapmd_wait); | |
541 | wait_for_completion(&kapmd_exit); | |
542 | } | |
543 | ||
544 | return ret; | |
545 | } | |
546 | ||
547 | static void __exit apm_exit(void) | |
548 | { | |
549 | misc_deregister(&apm_device); | |
550 | remove_proc_entry("apm", NULL); | |
551 | ||
552 | mips_apm_active = 0; | |
553 | wake_up(&kapmd_wait); | |
554 | wait_for_completion(&kapmd_exit); | |
555 | } | |
556 | ||
557 | module_init(apm_init); | |
558 | module_exit(apm_exit); | |
559 | ||
560 | MODULE_AUTHOR("Stephen Rothwell"); | |
561 | MODULE_DESCRIPTION("Advanced Power Management"); | |
562 | MODULE_LICENSE("GPL"); | |
563 | ||
564 | #ifndef MODULE | |
565 | static int __init apm_setup(char *str) | |
566 | { | |
567 | while ((str != NULL) && (*str != '\0')) { | |
568 | if (strncmp(str, "off", 3) == 0) | |
569 | apm_disabled = 1; | |
570 | if (strncmp(str, "on", 2) == 0) | |
571 | apm_disabled = 0; | |
572 | str = strchr(str, ','); | |
573 | if (str != NULL) | |
574 | str += strspn(str, ", \t"); | |
575 | } | |
576 | return 1; | |
577 | } | |
578 | ||
579 | __setup("apm=", apm_setup); | |
580 | #endif | |
581 | ||
582 | /** | |
583 | * apm_queue_event - queue an APM event for kapmd | |
584 | * @event: APM event | |
585 | * | |
586 | * Queue an APM event for kapmd to process and ultimately take the | |
587 | * appropriate action. Only a subset of events are handled: | |
588 | * %APM_LOW_BATTERY | |
589 | * %APM_POWER_STATUS_CHANGE | |
590 | * %APM_USER_SUSPEND | |
591 | * %APM_SYS_SUSPEND | |
592 | * %APM_CRITICAL_SUSPEND | |
593 | */ | |
594 | void apm_queue_event(apm_event_t event) | |
595 | { | |
596 | unsigned long flags; | |
597 | ||
598 | spin_lock_irqsave(&kapmd_queue_lock, flags); | |
599 | queue_add_event(&kapmd_queue, event); | |
600 | spin_unlock_irqrestore(&kapmd_queue_lock, flags); | |
601 | ||
602 | wake_up_interruptible(&kapmd_wait); | |
603 | } | |
604 | EXPORT_SYMBOL(apm_queue_event); |