xref: /linux/drivers/macintosh/adb.c (revision c0c914eca7f251c70facc37dfebeaf176601918d)
1 /*
2  * Device driver for the Apple Desktop Bus
3  * and the /dev/adb device on macintoshes.
4  *
5  * Copyright (C) 1996 Paul Mackerras.
6  *
7  * Modified to declare controllers as structures, added
8  * client notification of bus reset and handles PowerBook
9  * sleep, by Benjamin Herrenschmidt.
10  *
11  * To do:
12  *
13  * - /sys/bus/adb to list the devices and infos
14  * - more /dev/adb to allow userland to receive the
15  *   flow of auto-polling datas from a given device.
16  * - move bus probe to a kernel thread
17  */
18 
19 #include <linux/types.h>
20 #include <linux/errno.h>
21 #include <linux/kernel.h>
22 #include <linux/slab.h>
23 #include <linux/module.h>
24 #include <linux/fs.h>
25 #include <linux/mm.h>
26 #include <linux/sched.h>
27 #include <linux/adb.h>
28 #include <linux/cuda.h>
29 #include <linux/pmu.h>
30 #include <linux/notifier.h>
31 #include <linux/wait.h>
32 #include <linux/init.h>
33 #include <linux/delay.h>
34 #include <linux/spinlock.h>
35 #include <linux/completion.h>
36 #include <linux/device.h>
37 #include <linux/kthread.h>
38 #include <linux/platform_device.h>
39 #include <linux/mutex.h>
40 
41 #include <linux/uaccess.h>
42 #ifdef CONFIG_PPC
43 #include <asm/prom.h>
44 #include <asm/machdep.h>
45 #endif
46 
47 
48 EXPORT_SYMBOL(adb_client_list);
49 
50 extern struct adb_driver via_macii_driver;
51 extern struct adb_driver via_maciisi_driver;
52 extern struct adb_driver via_cuda_driver;
53 extern struct adb_driver adb_iop_driver;
54 extern struct adb_driver via_pmu_driver;
55 extern struct adb_driver macio_adb_driver;
56 
57 static DEFINE_MUTEX(adb_mutex);
58 static struct adb_driver *adb_driver_list[] = {
59 #ifdef CONFIG_ADB_MACII
60 	&via_macii_driver,
61 #endif
62 #ifdef CONFIG_ADB_MACIISI
63 	&via_maciisi_driver,
64 #endif
65 #ifdef CONFIG_ADB_CUDA
66 	&via_cuda_driver,
67 #endif
68 #ifdef CONFIG_ADB_IOP
69 	&adb_iop_driver,
70 #endif
71 #if defined(CONFIG_ADB_PMU) || defined(CONFIG_ADB_PMU68K)
72 	&via_pmu_driver,
73 #endif
74 #ifdef CONFIG_ADB_MACIO
75 	&macio_adb_driver,
76 #endif
77 	NULL
78 };
79 
80 static struct class *adb_dev_class;
81 
82 static struct adb_driver *adb_controller;
83 BLOCKING_NOTIFIER_HEAD(adb_client_list);
84 static int adb_got_sleep;
85 static int adb_inited;
86 static DEFINE_SEMAPHORE(adb_probe_mutex);
87 static int sleepy_trackpad;
88 static int autopoll_devs;
89 int __adb_probe_sync;
90 
91 static int adb_scan_bus(void);
92 static int do_adb_reset_bus(void);
93 static void adbdev_init(void);
94 static int try_handler_change(int, int);
95 
96 static struct adb_handler {
97 	void (*handler)(unsigned char *, int, int);
98 	int original_address;
99 	int handler_id;
100 	int busy;
101 } adb_handler[16];
102 
103 /*
104  * The adb_handler_mutex mutex protects all accesses to the original_address
105  * and handler_id fields of adb_handler[i] for all i, and changes to the
106  * handler field.
107  * Accesses to the handler field are protected by the adb_handler_lock
108  * rwlock.  It is held across all calls to any handler, so that by the
109  * time adb_unregister returns, we know that the old handler isn't being
110  * called.
111  */
112 static DEFINE_MUTEX(adb_handler_mutex);
113 static DEFINE_RWLOCK(adb_handler_lock);
114 
115 #if 0
116 static void printADBreply(struct adb_request *req)
117 {
118         int i;
119 
120         printk("adb reply (%d)", req->reply_len);
121         for(i = 0; i < req->reply_len; i++)
122                 printk(" %x", req->reply[i]);
123         printk("\n");
124 
125 }
126 #endif
127 
128 static int adb_scan_bus(void)
129 {
130 	int i, highFree=0, noMovement;
131 	int devmask = 0;
132 	struct adb_request req;
133 
134 	/* assumes adb_handler[] is all zeroes at this point */
135 	for (i = 1; i < 16; i++) {
136 		/* see if there is anything at address i */
137 		adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
138                             (i << 4) | 0xf);
139 		if (req.reply_len > 1)
140 			/* one or more devices at this address */
141 			adb_handler[i].original_address = i;
142 		else if (i > highFree)
143 			highFree = i;
144 	}
145 
146 	/* Note we reset noMovement to 0 each time we move a device */
147 	for (noMovement = 1; noMovement < 2 && highFree > 0; noMovement++) {
148 		for (i = 1; i < 16; i++) {
149 			if (adb_handler[i].original_address == 0)
150 				continue;
151 			/*
152 			 * Send a "talk register 3" command to address i
153 			 * to provoke a collision if there is more than
154 			 * one device at this address.
155 			 */
156 			adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
157 				    (i << 4) | 0xf);
158 			/*
159 			 * Move the device(s) which didn't detect a
160 			 * collision to address `highFree'.  Hopefully
161 			 * this only moves one device.
162 			 */
163 			adb_request(&req, NULL, ADBREQ_SYNC, 3,
164 				    (i<< 4) | 0xb, (highFree | 0x60), 0xfe);
165 			/*
166 			 * See if anybody actually moved. This is suggested
167 			 * by HW TechNote 01:
168 			 *
169 			 * http://developer.apple.com/technotes/hw/hw_01.html
170 			 */
171 			adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
172 				    (highFree << 4) | 0xf);
173 			if (req.reply_len <= 1) continue;
174 			/*
175 			 * Test whether there are any device(s) left
176 			 * at address i.
177 			 */
178 			adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
179 				    (i << 4) | 0xf);
180 			if (req.reply_len > 1) {
181 				/*
182 				 * There are still one or more devices
183 				 * left at address i.  Register the one(s)
184 				 * we moved to `highFree', and find a new
185 				 * value for highFree.
186 				 */
187 				adb_handler[highFree].original_address =
188 					adb_handler[i].original_address;
189 				while (highFree > 0 &&
190 				       adb_handler[highFree].original_address)
191 					highFree--;
192 				if (highFree <= 0)
193 					break;
194 
195 				noMovement = 0;
196 			} else {
197 				/*
198 				 * No devices left at address i; move the
199 				 * one(s) we moved to `highFree' back to i.
200 				 */
201 				adb_request(&req, NULL, ADBREQ_SYNC, 3,
202 					    (highFree << 4) | 0xb,
203 					    (i | 0x60), 0xfe);
204 			}
205 		}
206 	}
207 
208 	/* Now fill in the handler_id field of the adb_handler entries. */
209 	printk(KERN_DEBUG "adb devices:");
210 	for (i = 1; i < 16; i++) {
211 		if (adb_handler[i].original_address == 0)
212 			continue;
213 		adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
214 			    (i << 4) | 0xf);
215 		adb_handler[i].handler_id = req.reply[2];
216 		printk(" [%d]: %d %x", i, adb_handler[i].original_address,
217 		       adb_handler[i].handler_id);
218 		devmask |= 1 << i;
219 	}
220 	printk("\n");
221 	return devmask;
222 }
223 
224 /*
225  * This kernel task handles ADB probing. It dies once probing is
226  * completed.
227  */
228 static int
229 adb_probe_task(void *x)
230 {
231 	printk(KERN_INFO "adb: starting probe task...\n");
232 	do_adb_reset_bus();
233 	printk(KERN_INFO "adb: finished probe task...\n");
234 
235 	up(&adb_probe_mutex);
236 
237 	return 0;
238 }
239 
240 static void
241 __adb_probe_task(struct work_struct *bullshit)
242 {
243 	kthread_run(adb_probe_task, NULL, "kadbprobe");
244 }
245 
246 static DECLARE_WORK(adb_reset_work, __adb_probe_task);
247 
248 int
249 adb_reset_bus(void)
250 {
251 	if (__adb_probe_sync) {
252 		do_adb_reset_bus();
253 		return 0;
254 	}
255 
256 	down(&adb_probe_mutex);
257 	schedule_work(&adb_reset_work);
258 	return 0;
259 }
260 
261 #ifdef CONFIG_PM
262 /*
263  * notify clients before sleep
264  */
265 static int __adb_suspend(struct platform_device *dev, pm_message_t state)
266 {
267 	adb_got_sleep = 1;
268 	/* We need to get a lock on the probe thread */
269 	down(&adb_probe_mutex);
270 	/* Stop autopoll */
271 	if (adb_controller->autopoll)
272 		adb_controller->autopoll(0);
273 	blocking_notifier_call_chain(&adb_client_list, ADB_MSG_POWERDOWN, NULL);
274 
275 	return 0;
276 }
277 
278 static int adb_suspend(struct device *dev)
279 {
280 	return __adb_suspend(to_platform_device(dev), PMSG_SUSPEND);
281 }
282 
283 static int adb_freeze(struct device *dev)
284 {
285 	return __adb_suspend(to_platform_device(dev), PMSG_FREEZE);
286 }
287 
288 static int adb_poweroff(struct device *dev)
289 {
290 	return __adb_suspend(to_platform_device(dev), PMSG_HIBERNATE);
291 }
292 
293 /*
294  * reset bus after sleep
295  */
296 static int __adb_resume(struct platform_device *dev)
297 {
298 	adb_got_sleep = 0;
299 	up(&adb_probe_mutex);
300 	adb_reset_bus();
301 
302 	return 0;
303 }
304 
305 static int adb_resume(struct device *dev)
306 {
307 	return __adb_resume(to_platform_device(dev));
308 }
309 #endif /* CONFIG_PM */
310 
311 static int __init adb_init(void)
312 {
313 	struct adb_driver *driver;
314 	int i;
315 
316 #ifdef CONFIG_PPC32
317 	if (!machine_is(chrp) && !machine_is(powermac))
318 		return 0;
319 #endif
320 #ifdef CONFIG_MAC
321 	if (!MACH_IS_MAC)
322 		return 0;
323 #endif
324 
325 	/* xmon may do early-init */
326 	if (adb_inited)
327 		return 0;
328 	adb_inited = 1;
329 
330 	adb_controller = NULL;
331 
332 	i = 0;
333 	while ((driver = adb_driver_list[i++]) != NULL) {
334 		if (!driver->probe()) {
335 			adb_controller = driver;
336 			break;
337 		}
338 	}
339 	if (adb_controller != NULL && adb_controller->init &&
340 	    adb_controller->init())
341 		adb_controller = NULL;
342 	if (adb_controller == NULL) {
343 		printk(KERN_WARNING "Warning: no ADB interface detected\n");
344 	} else {
345 #ifdef CONFIG_PPC
346 		if (of_machine_is_compatible("AAPL,PowerBook1998") ||
347 			of_machine_is_compatible("PowerBook1,1"))
348 			sleepy_trackpad = 1;
349 #endif /* CONFIG_PPC */
350 
351 		adbdev_init();
352 		adb_reset_bus();
353 	}
354 	return 0;
355 }
356 
357 device_initcall(adb_init);
358 
359 static int
360 do_adb_reset_bus(void)
361 {
362 	int ret;
363 
364 	if (adb_controller == NULL)
365 		return -ENXIO;
366 
367 	if (adb_controller->autopoll)
368 		adb_controller->autopoll(0);
369 
370 	blocking_notifier_call_chain(&adb_client_list,
371 		ADB_MSG_PRE_RESET, NULL);
372 
373 	if (sleepy_trackpad) {
374 		/* Let the trackpad settle down */
375 		msleep(500);
376 	}
377 
378 	mutex_lock(&adb_handler_mutex);
379 	write_lock_irq(&adb_handler_lock);
380 	memset(adb_handler, 0, sizeof(adb_handler));
381 	write_unlock_irq(&adb_handler_lock);
382 
383 	/* That one is still a bit synchronous, oh well... */
384 	if (adb_controller->reset_bus)
385 		ret = adb_controller->reset_bus();
386 	else
387 		ret = 0;
388 
389 	if (sleepy_trackpad) {
390 		/* Let the trackpad settle down */
391 		msleep(1500);
392 	}
393 
394 	if (!ret) {
395 		autopoll_devs = adb_scan_bus();
396 		if (adb_controller->autopoll)
397 			adb_controller->autopoll(autopoll_devs);
398 	}
399 	mutex_unlock(&adb_handler_mutex);
400 
401 	blocking_notifier_call_chain(&adb_client_list,
402 		ADB_MSG_POST_RESET, NULL);
403 
404 	return ret;
405 }
406 
407 void
408 adb_poll(void)
409 {
410 	if ((adb_controller == NULL)||(adb_controller->poll == NULL))
411 		return;
412 	adb_controller->poll();
413 }
414 EXPORT_SYMBOL(adb_poll);
415 
416 static void adb_sync_req_done(struct adb_request *req)
417 {
418 	struct completion *comp = req->arg;
419 
420 	complete(comp);
421 }
422 
423 int
424 adb_request(struct adb_request *req, void (*done)(struct adb_request *),
425 	    int flags, int nbytes, ...)
426 {
427 	va_list list;
428 	int i;
429 	int rc;
430 	struct completion comp;
431 
432 	if ((adb_controller == NULL) || (adb_controller->send_request == NULL))
433 		return -ENXIO;
434 	if (nbytes < 1)
435 		return -EINVAL;
436 
437 	req->nbytes = nbytes+1;
438 	req->done = done;
439 	req->reply_expected = flags & ADBREQ_REPLY;
440 	req->data[0] = ADB_PACKET;
441 	va_start(list, nbytes);
442 	for (i = 0; i < nbytes; ++i)
443 		req->data[i+1] = va_arg(list, int);
444 	va_end(list);
445 
446 	if (flags & ADBREQ_NOSEND)
447 		return 0;
448 
449 	/* Synchronous requests block using an on-stack completion */
450 	if (flags & ADBREQ_SYNC) {
451 		WARN_ON(done);
452 		req->done = adb_sync_req_done;
453 		req->arg = &comp;
454 		init_completion(&comp);
455 	}
456 
457 	rc = adb_controller->send_request(req, 0);
458 
459 	if ((flags & ADBREQ_SYNC) && !rc && !req->complete)
460 		wait_for_completion(&comp);
461 
462 	return rc;
463 }
464 EXPORT_SYMBOL(adb_request);
465 
466  /* Ultimately this should return the number of devices with
467     the given default id.
468     And it does it now ! Note: changed behaviour: This function
469     will now register if default_id _and_ handler_id both match
470     but handler_id can be left to 0 to match with default_id only.
471     When handler_id is set, this function will try to adjust
472     the handler_id id it doesn't match. */
473 int
474 adb_register(int default_id, int handler_id, struct adb_ids *ids,
475 	     void (*handler)(unsigned char *, int, int))
476 {
477 	int i;
478 
479 	mutex_lock(&adb_handler_mutex);
480 	ids->nids = 0;
481 	for (i = 1; i < 16; i++) {
482 		if ((adb_handler[i].original_address == default_id) &&
483 		    (!handler_id || (handler_id == adb_handler[i].handler_id) ||
484 		    try_handler_change(i, handler_id))) {
485 			if (adb_handler[i].handler != 0) {
486 				printk(KERN_ERR
487 				       "Two handlers for ADB device %d\n",
488 				       default_id);
489 				continue;
490 			}
491 			write_lock_irq(&adb_handler_lock);
492 			adb_handler[i].handler = handler;
493 			write_unlock_irq(&adb_handler_lock);
494 			ids->id[ids->nids++] = i;
495 		}
496 	}
497 	mutex_unlock(&adb_handler_mutex);
498 	return ids->nids;
499 }
500 EXPORT_SYMBOL(adb_register);
501 
502 int
503 adb_unregister(int index)
504 {
505 	int ret = -ENODEV;
506 
507 	mutex_lock(&adb_handler_mutex);
508 	write_lock_irq(&adb_handler_lock);
509 	if (adb_handler[index].handler) {
510 		while(adb_handler[index].busy) {
511 			write_unlock_irq(&adb_handler_lock);
512 			yield();
513 			write_lock_irq(&adb_handler_lock);
514 		}
515 		ret = 0;
516 		adb_handler[index].handler = NULL;
517 	}
518 	write_unlock_irq(&adb_handler_lock);
519 	mutex_unlock(&adb_handler_mutex);
520 	return ret;
521 }
522 EXPORT_SYMBOL(adb_unregister);
523 
524 void
525 adb_input(unsigned char *buf, int nb, int autopoll)
526 {
527 	int i, id;
528 	static int dump_adb_input;
529 	unsigned long flags;
530 
531 	void (*handler)(unsigned char *, int, int);
532 
533 	/* We skip keystrokes and mouse moves when the sleep process
534 	 * has been started. We stop autopoll, but this is another security
535 	 */
536 	if (adb_got_sleep)
537 		return;
538 
539 	id = buf[0] >> 4;
540 	if (dump_adb_input) {
541 		printk(KERN_INFO "adb packet: ");
542 		for (i = 0; i < nb; ++i)
543 			printk(" %x", buf[i]);
544 		printk(", id = %d\n", id);
545 	}
546 	write_lock_irqsave(&adb_handler_lock, flags);
547 	handler = adb_handler[id].handler;
548 	if (handler != NULL)
549 		adb_handler[id].busy = 1;
550 	write_unlock_irqrestore(&adb_handler_lock, flags);
551 	if (handler != NULL) {
552 		(*handler)(buf, nb, autopoll);
553 		wmb();
554 		adb_handler[id].busy = 0;
555 	}
556 
557 }
558 
559 /* Try to change handler to new_id. Will return 1 if successful. */
560 static int try_handler_change(int address, int new_id)
561 {
562 	struct adb_request req;
563 
564 	if (adb_handler[address].handler_id == new_id)
565 	    return 1;
566 	adb_request(&req, NULL, ADBREQ_SYNC, 3,
567 	    ADB_WRITEREG(address, 3), address | 0x20, new_id);
568 	adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
569 	    ADB_READREG(address, 3));
570 	if (req.reply_len < 2)
571 	    return 0;
572 	if (req.reply[2] != new_id)
573 	    return 0;
574 	adb_handler[address].handler_id = req.reply[2];
575 
576 	return 1;
577 }
578 
579 int
580 adb_try_handler_change(int address, int new_id)
581 {
582 	int ret;
583 
584 	mutex_lock(&adb_handler_mutex);
585 	ret = try_handler_change(address, new_id);
586 	mutex_unlock(&adb_handler_mutex);
587 	return ret;
588 }
589 EXPORT_SYMBOL(adb_try_handler_change);
590 
591 int
592 adb_get_infos(int address, int *original_address, int *handler_id)
593 {
594 	mutex_lock(&adb_handler_mutex);
595 	*original_address = adb_handler[address].original_address;
596 	*handler_id = adb_handler[address].handler_id;
597 	mutex_unlock(&adb_handler_mutex);
598 
599 	return (*original_address != 0);
600 }
601 
602 
603 /*
604  * /dev/adb device driver.
605  */
606 
607 #define ADB_MAJOR	56	/* major number for /dev/adb */
608 
609 struct adbdev_state {
610 	spinlock_t	lock;
611 	atomic_t	n_pending;
612 	struct adb_request *completed;
613   	wait_queue_head_t wait_queue;
614 	int		inuse;
615 };
616 
617 static void adb_write_done(struct adb_request *req)
618 {
619 	struct adbdev_state *state = (struct adbdev_state *) req->arg;
620 	unsigned long flags;
621 
622 	if (!req->complete) {
623 		req->reply_len = 0;
624 		req->complete = 1;
625 	}
626 	spin_lock_irqsave(&state->lock, flags);
627 	atomic_dec(&state->n_pending);
628 	if (!state->inuse) {
629 		kfree(req);
630 		if (atomic_read(&state->n_pending) == 0) {
631 			spin_unlock_irqrestore(&state->lock, flags);
632 			kfree(state);
633 			return;
634 		}
635 	} else {
636 		struct adb_request **ap = &state->completed;
637 		while (*ap != NULL)
638 			ap = &(*ap)->next;
639 		req->next = NULL;
640 		*ap = req;
641 		wake_up_interruptible(&state->wait_queue);
642 	}
643 	spin_unlock_irqrestore(&state->lock, flags);
644 }
645 
646 static int
647 do_adb_query(struct adb_request *req)
648 {
649 	int	ret = -EINVAL;
650 
651 	switch(req->data[1]) {
652 	case ADB_QUERY_GETDEVINFO:
653 		if (req->nbytes < 3)
654 			break;
655 		mutex_lock(&adb_handler_mutex);
656 		req->reply[0] = adb_handler[req->data[2]].original_address;
657 		req->reply[1] = adb_handler[req->data[2]].handler_id;
658 		mutex_unlock(&adb_handler_mutex);
659 		req->complete = 1;
660 		req->reply_len = 2;
661 		adb_write_done(req);
662 		ret = 0;
663 		break;
664 	}
665 	return ret;
666 }
667 
668 static int adb_open(struct inode *inode, struct file *file)
669 {
670 	struct adbdev_state *state;
671 	int ret = 0;
672 
673 	mutex_lock(&adb_mutex);
674 	if (iminor(inode) > 0 || adb_controller == NULL) {
675 		ret = -ENXIO;
676 		goto out;
677 	}
678 	state = kmalloc(sizeof(struct adbdev_state), GFP_KERNEL);
679 	if (state == 0) {
680 		ret = -ENOMEM;
681 		goto out;
682 	}
683 	file->private_data = state;
684 	spin_lock_init(&state->lock);
685 	atomic_set(&state->n_pending, 0);
686 	state->completed = NULL;
687 	init_waitqueue_head(&state->wait_queue);
688 	state->inuse = 1;
689 
690 out:
691 	mutex_unlock(&adb_mutex);
692 	return ret;
693 }
694 
695 static int adb_release(struct inode *inode, struct file *file)
696 {
697 	struct adbdev_state *state = file->private_data;
698 	unsigned long flags;
699 
700 	mutex_lock(&adb_mutex);
701 	if (state) {
702 		file->private_data = NULL;
703 		spin_lock_irqsave(&state->lock, flags);
704 		if (atomic_read(&state->n_pending) == 0
705 		    && state->completed == NULL) {
706 			spin_unlock_irqrestore(&state->lock, flags);
707 			kfree(state);
708 		} else {
709 			state->inuse = 0;
710 			spin_unlock_irqrestore(&state->lock, flags);
711 		}
712 	}
713 	mutex_unlock(&adb_mutex);
714 	return 0;
715 }
716 
717 static ssize_t adb_read(struct file *file, char __user *buf,
718 			size_t count, loff_t *ppos)
719 {
720 	int ret = 0;
721 	struct adbdev_state *state = file->private_data;
722 	struct adb_request *req;
723 	DECLARE_WAITQUEUE(wait, current);
724 	unsigned long flags;
725 
726 	if (count < 2)
727 		return -EINVAL;
728 	if (count > sizeof(req->reply))
729 		count = sizeof(req->reply);
730 	if (!access_ok(VERIFY_WRITE, buf, count))
731 		return -EFAULT;
732 
733 	req = NULL;
734 	spin_lock_irqsave(&state->lock, flags);
735 	add_wait_queue(&state->wait_queue, &wait);
736 	set_current_state(TASK_INTERRUPTIBLE);
737 
738 	for (;;) {
739 		req = state->completed;
740 		if (req != NULL)
741 			state->completed = req->next;
742 		else if (atomic_read(&state->n_pending) == 0)
743 			ret = -EIO;
744 		if (req != NULL || ret != 0)
745 			break;
746 
747 		if (file->f_flags & O_NONBLOCK) {
748 			ret = -EAGAIN;
749 			break;
750 		}
751 		if (signal_pending(current)) {
752 			ret = -ERESTARTSYS;
753 			break;
754 		}
755 		spin_unlock_irqrestore(&state->lock, flags);
756 		schedule();
757 		spin_lock_irqsave(&state->lock, flags);
758 	}
759 
760 	set_current_state(TASK_RUNNING);
761 	remove_wait_queue(&state->wait_queue, &wait);
762 	spin_unlock_irqrestore(&state->lock, flags);
763 
764 	if (ret)
765 		return ret;
766 
767 	ret = req->reply_len;
768 	if (ret > count)
769 		ret = count;
770 	if (ret > 0 && copy_to_user(buf, req->reply, ret))
771 		ret = -EFAULT;
772 
773 	kfree(req);
774 	return ret;
775 }
776 
777 static ssize_t adb_write(struct file *file, const char __user *buf,
778 			 size_t count, loff_t *ppos)
779 {
780 	int ret/*, i*/;
781 	struct adbdev_state *state = file->private_data;
782 	struct adb_request *req;
783 
784 	if (count < 2 || count > sizeof(req->data))
785 		return -EINVAL;
786 	if (adb_controller == NULL)
787 		return -ENXIO;
788 	if (!access_ok(VERIFY_READ, buf, count))
789 		return -EFAULT;
790 
791 	req = kmalloc(sizeof(struct adb_request),
792 					     GFP_KERNEL);
793 	if (req == NULL)
794 		return -ENOMEM;
795 
796 	req->nbytes = count;
797 	req->done = adb_write_done;
798 	req->arg = (void *) state;
799 	req->complete = 0;
800 
801 	ret = -EFAULT;
802 	if (copy_from_user(req->data, buf, count))
803 		goto out;
804 
805 	atomic_inc(&state->n_pending);
806 
807 	/* If a probe is in progress or we are sleeping, wait for it to complete */
808 	down(&adb_probe_mutex);
809 
810 	/* Queries are special requests sent to the ADB driver itself */
811 	if (req->data[0] == ADB_QUERY) {
812 		if (count > 1)
813 			ret = do_adb_query(req);
814 		else
815 			ret = -EINVAL;
816 		up(&adb_probe_mutex);
817 	}
818 	/* Special case for ADB_BUSRESET request, all others are sent to
819 	   the controller */
820 	else if ((req->data[0] == ADB_PACKET) && (count > 1)
821 		&& (req->data[1] == ADB_BUSRESET)) {
822 		ret = do_adb_reset_bus();
823 		up(&adb_probe_mutex);
824 		atomic_dec(&state->n_pending);
825 		if (ret == 0)
826 			ret = count;
827 		goto out;
828 	} else {
829 		req->reply_expected = ((req->data[1] & 0xc) == 0xc);
830 		if (adb_controller && adb_controller->send_request)
831 			ret = adb_controller->send_request(req, 0);
832 		else
833 			ret = -ENXIO;
834 		up(&adb_probe_mutex);
835 	}
836 
837 	if (ret != 0) {
838 		atomic_dec(&state->n_pending);
839 		goto out;
840 	}
841 	return count;
842 
843 out:
844 	kfree(req);
845 	return ret;
846 }
847 
848 static const struct file_operations adb_fops = {
849 	.owner		= THIS_MODULE,
850 	.llseek		= no_llseek,
851 	.read		= adb_read,
852 	.write		= adb_write,
853 	.open		= adb_open,
854 	.release	= adb_release,
855 };
856 
857 #ifdef CONFIG_PM
858 static const struct dev_pm_ops adb_dev_pm_ops = {
859 	.suspend = adb_suspend,
860 	.resume = adb_resume,
861 	/* Hibernate hooks */
862 	.freeze = adb_freeze,
863 	.thaw = adb_resume,
864 	.poweroff = adb_poweroff,
865 	.restore = adb_resume,
866 };
867 #endif
868 
869 static struct platform_driver adb_pfdrv = {
870 	.driver = {
871 		.name = "adb",
872 #ifdef CONFIG_PM
873 		.pm = &adb_dev_pm_ops,
874 #endif
875 	},
876 };
877 
878 static struct platform_device adb_pfdev = {
879 	.name = "adb",
880 };
881 
882 static int __init
883 adb_dummy_probe(struct platform_device *dev)
884 {
885 	if (dev == &adb_pfdev)
886 		return 0;
887 	return -ENODEV;
888 }
889 
890 static void __init
891 adbdev_init(void)
892 {
893 	if (register_chrdev(ADB_MAJOR, "adb", &adb_fops)) {
894 		printk(KERN_ERR "adb: unable to get major %d\n", ADB_MAJOR);
895 		return;
896 	}
897 
898 	adb_dev_class = class_create(THIS_MODULE, "adb");
899 	if (IS_ERR(adb_dev_class))
900 		return;
901 	device_create(adb_dev_class, NULL, MKDEV(ADB_MAJOR, 0), NULL, "adb");
902 
903 	platform_device_register(&adb_pfdev);
904 	platform_driver_probe(&adb_pfdrv, adb_dummy_probe);
905 }
906