xref: /openbmc/linux/drivers/macintosh/adb.c (revision 711aab1d)
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/signal.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_cuda_driver;
52 extern struct adb_driver adb_iop_driver;
53 extern struct adb_driver via_pmu_driver;
54 extern struct adb_driver macio_adb_driver;
55 
56 static DEFINE_MUTEX(adb_mutex);
57 static struct adb_driver *adb_driver_list[] = {
58 #ifdef CONFIG_ADB_MACII
59 	&via_macii_driver,
60 #endif
61 #ifdef CONFIG_ADB_CUDA
62 	&via_cuda_driver,
63 #endif
64 #ifdef CONFIG_ADB_IOP
65 	&adb_iop_driver,
66 #endif
67 #if defined(CONFIG_ADB_PMU) || defined(CONFIG_ADB_PMU68K)
68 	&via_pmu_driver,
69 #endif
70 #ifdef CONFIG_ADB_MACIO
71 	&macio_adb_driver,
72 #endif
73 	NULL
74 };
75 
76 static struct class *adb_dev_class;
77 
78 static struct adb_driver *adb_controller;
79 BLOCKING_NOTIFIER_HEAD(adb_client_list);
80 static int adb_got_sleep;
81 static int adb_inited;
82 static DEFINE_SEMAPHORE(adb_probe_mutex);
83 static int sleepy_trackpad;
84 static int autopoll_devs;
85 int __adb_probe_sync;
86 
87 static int adb_scan_bus(void);
88 static int do_adb_reset_bus(void);
89 static void adbdev_init(void);
90 static int try_handler_change(int, int);
91 
92 static struct adb_handler {
93 	void (*handler)(unsigned char *, int, int);
94 	int original_address;
95 	int handler_id;
96 	int busy;
97 } adb_handler[16];
98 
99 /*
100  * The adb_handler_mutex mutex protects all accesses to the original_address
101  * and handler_id fields of adb_handler[i] for all i, and changes to the
102  * handler field.
103  * Accesses to the handler field are protected by the adb_handler_lock
104  * rwlock.  It is held across all calls to any handler, so that by the
105  * time adb_unregister returns, we know that the old handler isn't being
106  * called.
107  */
108 static DEFINE_MUTEX(adb_handler_mutex);
109 static DEFINE_RWLOCK(adb_handler_lock);
110 
111 #if 0
112 static void printADBreply(struct adb_request *req)
113 {
114         int i;
115 
116         printk("adb reply (%d)", req->reply_len);
117         for(i = 0; i < req->reply_len; i++)
118                 printk(" %x", req->reply[i]);
119         printk("\n");
120 
121 }
122 #endif
123 
124 static int adb_scan_bus(void)
125 {
126 	int i, highFree=0, noMovement;
127 	int devmask = 0;
128 	struct adb_request req;
129 
130 	/* assumes adb_handler[] is all zeroes at this point */
131 	for (i = 1; i < 16; i++) {
132 		/* see if there is anything at address i */
133 		adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
134                             (i << 4) | 0xf);
135 		if (req.reply_len > 1)
136 			/* one or more devices at this address */
137 			adb_handler[i].original_address = i;
138 		else if (i > highFree)
139 			highFree = i;
140 	}
141 
142 	/* Note we reset noMovement to 0 each time we move a device */
143 	for (noMovement = 1; noMovement < 2 && highFree > 0; noMovement++) {
144 		for (i = 1; i < 16; i++) {
145 			if (adb_handler[i].original_address == 0)
146 				continue;
147 			/*
148 			 * Send a "talk register 3" command to address i
149 			 * to provoke a collision if there is more than
150 			 * one device at this address.
151 			 */
152 			adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
153 				    (i << 4) | 0xf);
154 			/*
155 			 * Move the device(s) which didn't detect a
156 			 * collision to address `highFree'.  Hopefully
157 			 * this only moves one device.
158 			 */
159 			adb_request(&req, NULL, ADBREQ_SYNC, 3,
160 				    (i<< 4) | 0xb, (highFree | 0x60), 0xfe);
161 			/*
162 			 * See if anybody actually moved. This is suggested
163 			 * by HW TechNote 01:
164 			 *
165 			 * http://developer.apple.com/technotes/hw/hw_01.html
166 			 */
167 			adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
168 				    (highFree << 4) | 0xf);
169 			if (req.reply_len <= 1) continue;
170 			/*
171 			 * Test whether there are any device(s) left
172 			 * at address i.
173 			 */
174 			adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
175 				    (i << 4) | 0xf);
176 			if (req.reply_len > 1) {
177 				/*
178 				 * There are still one or more devices
179 				 * left at address i.  Register the one(s)
180 				 * we moved to `highFree', and find a new
181 				 * value for highFree.
182 				 */
183 				adb_handler[highFree].original_address =
184 					adb_handler[i].original_address;
185 				while (highFree > 0 &&
186 				       adb_handler[highFree].original_address)
187 					highFree--;
188 				if (highFree <= 0)
189 					break;
190 
191 				noMovement = 0;
192 			} else {
193 				/*
194 				 * No devices left at address i; move the
195 				 * one(s) we moved to `highFree' back to i.
196 				 */
197 				adb_request(&req, NULL, ADBREQ_SYNC, 3,
198 					    (highFree << 4) | 0xb,
199 					    (i | 0x60), 0xfe);
200 			}
201 		}
202 	}
203 
204 	/* Now fill in the handler_id field of the adb_handler entries. */
205 	printk(KERN_DEBUG "adb devices:");
206 	for (i = 1; i < 16; i++) {
207 		if (adb_handler[i].original_address == 0)
208 			continue;
209 		adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
210 			    (i << 4) | 0xf);
211 		adb_handler[i].handler_id = req.reply[2];
212 		printk(" [%d]: %d %x", i, adb_handler[i].original_address,
213 		       adb_handler[i].handler_id);
214 		devmask |= 1 << i;
215 	}
216 	printk("\n");
217 	return devmask;
218 }
219 
220 /*
221  * This kernel task handles ADB probing. It dies once probing is
222  * completed.
223  */
224 static int
225 adb_probe_task(void *x)
226 {
227 	printk(KERN_INFO "adb: starting probe task...\n");
228 	do_adb_reset_bus();
229 	printk(KERN_INFO "adb: finished probe task...\n");
230 
231 	up(&adb_probe_mutex);
232 
233 	return 0;
234 }
235 
236 static void
237 __adb_probe_task(struct work_struct *bullshit)
238 {
239 	kthread_run(adb_probe_task, NULL, "kadbprobe");
240 }
241 
242 static DECLARE_WORK(adb_reset_work, __adb_probe_task);
243 
244 int
245 adb_reset_bus(void)
246 {
247 	if (__adb_probe_sync) {
248 		do_adb_reset_bus();
249 		return 0;
250 	}
251 
252 	down(&adb_probe_mutex);
253 	schedule_work(&adb_reset_work);
254 	return 0;
255 }
256 
257 #ifdef CONFIG_PM
258 /*
259  * notify clients before sleep
260  */
261 static int __adb_suspend(struct platform_device *dev, pm_message_t state)
262 {
263 	adb_got_sleep = 1;
264 	/* We need to get a lock on the probe thread */
265 	down(&adb_probe_mutex);
266 	/* Stop autopoll */
267 	if (adb_controller->autopoll)
268 		adb_controller->autopoll(0);
269 	blocking_notifier_call_chain(&adb_client_list, ADB_MSG_POWERDOWN, NULL);
270 
271 	return 0;
272 }
273 
274 static int adb_suspend(struct device *dev)
275 {
276 	return __adb_suspend(to_platform_device(dev), PMSG_SUSPEND);
277 }
278 
279 static int adb_freeze(struct device *dev)
280 {
281 	return __adb_suspend(to_platform_device(dev), PMSG_FREEZE);
282 }
283 
284 static int adb_poweroff(struct device *dev)
285 {
286 	return __adb_suspend(to_platform_device(dev), PMSG_HIBERNATE);
287 }
288 
289 /*
290  * reset bus after sleep
291  */
292 static int __adb_resume(struct platform_device *dev)
293 {
294 	adb_got_sleep = 0;
295 	up(&adb_probe_mutex);
296 	adb_reset_bus();
297 
298 	return 0;
299 }
300 
301 static int adb_resume(struct device *dev)
302 {
303 	return __adb_resume(to_platform_device(dev));
304 }
305 #endif /* CONFIG_PM */
306 
307 static int __init adb_init(void)
308 {
309 	struct adb_driver *driver;
310 	int i;
311 
312 #ifdef CONFIG_PPC32
313 	if (!machine_is(chrp) && !machine_is(powermac))
314 		return 0;
315 #endif
316 #ifdef CONFIG_MAC
317 	if (!MACH_IS_MAC)
318 		return 0;
319 #endif
320 
321 	/* xmon may do early-init */
322 	if (adb_inited)
323 		return 0;
324 	adb_inited = 1;
325 
326 	adb_controller = NULL;
327 
328 	i = 0;
329 	while ((driver = adb_driver_list[i++]) != NULL) {
330 		if (!driver->probe()) {
331 			adb_controller = driver;
332 			break;
333 		}
334 	}
335 	if (adb_controller != NULL && adb_controller->init &&
336 	    adb_controller->init())
337 		adb_controller = NULL;
338 	if (adb_controller == NULL) {
339 		printk(KERN_WARNING "Warning: no ADB interface detected\n");
340 	} else {
341 #ifdef CONFIG_PPC
342 		if (of_machine_is_compatible("AAPL,PowerBook1998") ||
343 			of_machine_is_compatible("PowerBook1,1"))
344 			sleepy_trackpad = 1;
345 #endif /* CONFIG_PPC */
346 
347 		adbdev_init();
348 		adb_reset_bus();
349 	}
350 	return 0;
351 }
352 
353 device_initcall(adb_init);
354 
355 static int
356 do_adb_reset_bus(void)
357 {
358 	int ret;
359 
360 	if (adb_controller == NULL)
361 		return -ENXIO;
362 
363 	if (adb_controller->autopoll)
364 		adb_controller->autopoll(0);
365 
366 	blocking_notifier_call_chain(&adb_client_list,
367 		ADB_MSG_PRE_RESET, NULL);
368 
369 	if (sleepy_trackpad) {
370 		/* Let the trackpad settle down */
371 		msleep(500);
372 	}
373 
374 	mutex_lock(&adb_handler_mutex);
375 	write_lock_irq(&adb_handler_lock);
376 	memset(adb_handler, 0, sizeof(adb_handler));
377 	write_unlock_irq(&adb_handler_lock);
378 
379 	/* That one is still a bit synchronous, oh well... */
380 	if (adb_controller->reset_bus)
381 		ret = adb_controller->reset_bus();
382 	else
383 		ret = 0;
384 
385 	if (sleepy_trackpad) {
386 		/* Let the trackpad settle down */
387 		msleep(1500);
388 	}
389 
390 	if (!ret) {
391 		autopoll_devs = adb_scan_bus();
392 		if (adb_controller->autopoll)
393 			adb_controller->autopoll(autopoll_devs);
394 	}
395 	mutex_unlock(&adb_handler_mutex);
396 
397 	blocking_notifier_call_chain(&adb_client_list,
398 		ADB_MSG_POST_RESET, NULL);
399 
400 	return ret;
401 }
402 
403 void
404 adb_poll(void)
405 {
406 	if ((adb_controller == NULL)||(adb_controller->poll == NULL))
407 		return;
408 	adb_controller->poll();
409 }
410 EXPORT_SYMBOL(adb_poll);
411 
412 static void adb_sync_req_done(struct adb_request *req)
413 {
414 	struct completion *comp = req->arg;
415 
416 	complete(comp);
417 }
418 
419 int
420 adb_request(struct adb_request *req, void (*done)(struct adb_request *),
421 	    int flags, int nbytes, ...)
422 {
423 	va_list list;
424 	int i;
425 	int rc;
426 	struct completion comp;
427 
428 	if ((adb_controller == NULL) || (adb_controller->send_request == NULL))
429 		return -ENXIO;
430 	if (nbytes < 1)
431 		return -EINVAL;
432 
433 	req->nbytes = nbytes+1;
434 	req->done = done;
435 	req->reply_expected = flags & ADBREQ_REPLY;
436 	req->data[0] = ADB_PACKET;
437 	va_start(list, nbytes);
438 	for (i = 0; i < nbytes; ++i)
439 		req->data[i+1] = va_arg(list, int);
440 	va_end(list);
441 
442 	if (flags & ADBREQ_NOSEND)
443 		return 0;
444 
445 	/* Synchronous requests block using an on-stack completion */
446 	if (flags & ADBREQ_SYNC) {
447 		WARN_ON(done);
448 		req->done = adb_sync_req_done;
449 		req->arg = &comp;
450 		init_completion(&comp);
451 	}
452 
453 	rc = adb_controller->send_request(req, 0);
454 
455 	if ((flags & ADBREQ_SYNC) && !rc && !req->complete)
456 		wait_for_completion(&comp);
457 
458 	return rc;
459 }
460 EXPORT_SYMBOL(adb_request);
461 
462  /* Ultimately this should return the number of devices with
463     the given default id.
464     And it does it now ! Note: changed behaviour: This function
465     will now register if default_id _and_ handler_id both match
466     but handler_id can be left to 0 to match with default_id only.
467     When handler_id is set, this function will try to adjust
468     the handler_id id it doesn't match. */
469 int
470 adb_register(int default_id, int handler_id, struct adb_ids *ids,
471 	     void (*handler)(unsigned char *, int, int))
472 {
473 	int i;
474 
475 	mutex_lock(&adb_handler_mutex);
476 	ids->nids = 0;
477 	for (i = 1; i < 16; i++) {
478 		if ((adb_handler[i].original_address == default_id) &&
479 		    (!handler_id || (handler_id == adb_handler[i].handler_id) ||
480 		    try_handler_change(i, handler_id))) {
481 			if (adb_handler[i].handler != 0) {
482 				printk(KERN_ERR
483 				       "Two handlers for ADB device %d\n",
484 				       default_id);
485 				continue;
486 			}
487 			write_lock_irq(&adb_handler_lock);
488 			adb_handler[i].handler = handler;
489 			write_unlock_irq(&adb_handler_lock);
490 			ids->id[ids->nids++] = i;
491 		}
492 	}
493 	mutex_unlock(&adb_handler_mutex);
494 	return ids->nids;
495 }
496 EXPORT_SYMBOL(adb_register);
497 
498 int
499 adb_unregister(int index)
500 {
501 	int ret = -ENODEV;
502 
503 	mutex_lock(&adb_handler_mutex);
504 	write_lock_irq(&adb_handler_lock);
505 	if (adb_handler[index].handler) {
506 		while(adb_handler[index].busy) {
507 			write_unlock_irq(&adb_handler_lock);
508 			yield();
509 			write_lock_irq(&adb_handler_lock);
510 		}
511 		ret = 0;
512 		adb_handler[index].handler = NULL;
513 	}
514 	write_unlock_irq(&adb_handler_lock);
515 	mutex_unlock(&adb_handler_mutex);
516 	return ret;
517 }
518 EXPORT_SYMBOL(adb_unregister);
519 
520 void
521 adb_input(unsigned char *buf, int nb, int autopoll)
522 {
523 	int i, id;
524 	static int dump_adb_input;
525 	unsigned long flags;
526 
527 	void (*handler)(unsigned char *, int, int);
528 
529 	/* We skip keystrokes and mouse moves when the sleep process
530 	 * has been started. We stop autopoll, but this is another security
531 	 */
532 	if (adb_got_sleep)
533 		return;
534 
535 	id = buf[0] >> 4;
536 	if (dump_adb_input) {
537 		printk(KERN_INFO "adb packet: ");
538 		for (i = 0; i < nb; ++i)
539 			printk(" %x", buf[i]);
540 		printk(", id = %d\n", id);
541 	}
542 	write_lock_irqsave(&adb_handler_lock, flags);
543 	handler = adb_handler[id].handler;
544 	if (handler != NULL)
545 		adb_handler[id].busy = 1;
546 	write_unlock_irqrestore(&adb_handler_lock, flags);
547 	if (handler != NULL) {
548 		(*handler)(buf, nb, autopoll);
549 		wmb();
550 		adb_handler[id].busy = 0;
551 	}
552 
553 }
554 
555 /* Try to change handler to new_id. Will return 1 if successful. */
556 static int try_handler_change(int address, int new_id)
557 {
558 	struct adb_request req;
559 
560 	if (adb_handler[address].handler_id == new_id)
561 	    return 1;
562 	adb_request(&req, NULL, ADBREQ_SYNC, 3,
563 	    ADB_WRITEREG(address, 3), address | 0x20, new_id);
564 	adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
565 	    ADB_READREG(address, 3));
566 	if (req.reply_len < 2)
567 	    return 0;
568 	if (req.reply[2] != new_id)
569 	    return 0;
570 	adb_handler[address].handler_id = req.reply[2];
571 
572 	return 1;
573 }
574 
575 int
576 adb_try_handler_change(int address, int new_id)
577 {
578 	int ret;
579 
580 	mutex_lock(&adb_handler_mutex);
581 	ret = try_handler_change(address, new_id);
582 	mutex_unlock(&adb_handler_mutex);
583 	return ret;
584 }
585 EXPORT_SYMBOL(adb_try_handler_change);
586 
587 int
588 adb_get_infos(int address, int *original_address, int *handler_id)
589 {
590 	mutex_lock(&adb_handler_mutex);
591 	*original_address = adb_handler[address].original_address;
592 	*handler_id = adb_handler[address].handler_id;
593 	mutex_unlock(&adb_handler_mutex);
594 
595 	return (*original_address != 0);
596 }
597 
598 
599 /*
600  * /dev/adb device driver.
601  */
602 
603 #define ADB_MAJOR	56	/* major number for /dev/adb */
604 
605 struct adbdev_state {
606 	spinlock_t	lock;
607 	atomic_t	n_pending;
608 	struct adb_request *completed;
609   	wait_queue_head_t wait_queue;
610 	int		inuse;
611 };
612 
613 static void adb_write_done(struct adb_request *req)
614 {
615 	struct adbdev_state *state = (struct adbdev_state *) req->arg;
616 	unsigned long flags;
617 
618 	if (!req->complete) {
619 		req->reply_len = 0;
620 		req->complete = 1;
621 	}
622 	spin_lock_irqsave(&state->lock, flags);
623 	atomic_dec(&state->n_pending);
624 	if (!state->inuse) {
625 		kfree(req);
626 		if (atomic_read(&state->n_pending) == 0) {
627 			spin_unlock_irqrestore(&state->lock, flags);
628 			kfree(state);
629 			return;
630 		}
631 	} else {
632 		struct adb_request **ap = &state->completed;
633 		while (*ap != NULL)
634 			ap = &(*ap)->next;
635 		req->next = NULL;
636 		*ap = req;
637 		wake_up_interruptible(&state->wait_queue);
638 	}
639 	spin_unlock_irqrestore(&state->lock, flags);
640 }
641 
642 static int
643 do_adb_query(struct adb_request *req)
644 {
645 	int	ret = -EINVAL;
646 
647 	switch(req->data[1]) {
648 	case ADB_QUERY_GETDEVINFO:
649 		if (req->nbytes < 3)
650 			break;
651 		mutex_lock(&adb_handler_mutex);
652 		req->reply[0] = adb_handler[req->data[2]].original_address;
653 		req->reply[1] = adb_handler[req->data[2]].handler_id;
654 		mutex_unlock(&adb_handler_mutex);
655 		req->complete = 1;
656 		req->reply_len = 2;
657 		adb_write_done(req);
658 		ret = 0;
659 		break;
660 	}
661 	return ret;
662 }
663 
664 static int adb_open(struct inode *inode, struct file *file)
665 {
666 	struct adbdev_state *state;
667 	int ret = 0;
668 
669 	mutex_lock(&adb_mutex);
670 	if (iminor(inode) > 0 || adb_controller == NULL) {
671 		ret = -ENXIO;
672 		goto out;
673 	}
674 	state = kmalloc(sizeof(struct adbdev_state), GFP_KERNEL);
675 	if (state == 0) {
676 		ret = -ENOMEM;
677 		goto out;
678 	}
679 	file->private_data = state;
680 	spin_lock_init(&state->lock);
681 	atomic_set(&state->n_pending, 0);
682 	state->completed = NULL;
683 	init_waitqueue_head(&state->wait_queue);
684 	state->inuse = 1;
685 
686 out:
687 	mutex_unlock(&adb_mutex);
688 	return ret;
689 }
690 
691 static int adb_release(struct inode *inode, struct file *file)
692 {
693 	struct adbdev_state *state = file->private_data;
694 	unsigned long flags;
695 
696 	mutex_lock(&adb_mutex);
697 	if (state) {
698 		file->private_data = NULL;
699 		spin_lock_irqsave(&state->lock, flags);
700 		if (atomic_read(&state->n_pending) == 0
701 		    && state->completed == NULL) {
702 			spin_unlock_irqrestore(&state->lock, flags);
703 			kfree(state);
704 		} else {
705 			state->inuse = 0;
706 			spin_unlock_irqrestore(&state->lock, flags);
707 		}
708 	}
709 	mutex_unlock(&adb_mutex);
710 	return 0;
711 }
712 
713 static ssize_t adb_read(struct file *file, char __user *buf,
714 			size_t count, loff_t *ppos)
715 {
716 	int ret = 0;
717 	struct adbdev_state *state = file->private_data;
718 	struct adb_request *req;
719 	DECLARE_WAITQUEUE(wait, current);
720 	unsigned long flags;
721 
722 	if (count < 2)
723 		return -EINVAL;
724 	if (count > sizeof(req->reply))
725 		count = sizeof(req->reply);
726 
727 	req = NULL;
728 	spin_lock_irqsave(&state->lock, flags);
729 	add_wait_queue(&state->wait_queue, &wait);
730 	set_current_state(TASK_INTERRUPTIBLE);
731 
732 	for (;;) {
733 		req = state->completed;
734 		if (req != NULL)
735 			state->completed = req->next;
736 		else if (atomic_read(&state->n_pending) == 0)
737 			ret = -EIO;
738 		if (req != NULL || ret != 0)
739 			break;
740 
741 		if (file->f_flags & O_NONBLOCK) {
742 			ret = -EAGAIN;
743 			break;
744 		}
745 		if (signal_pending(current)) {
746 			ret = -ERESTARTSYS;
747 			break;
748 		}
749 		spin_unlock_irqrestore(&state->lock, flags);
750 		schedule();
751 		spin_lock_irqsave(&state->lock, flags);
752 	}
753 
754 	set_current_state(TASK_RUNNING);
755 	remove_wait_queue(&state->wait_queue, &wait);
756 	spin_unlock_irqrestore(&state->lock, flags);
757 
758 	if (ret)
759 		return ret;
760 
761 	ret = req->reply_len;
762 	if (ret > count)
763 		ret = count;
764 	if (ret > 0 && copy_to_user(buf, req->reply, ret))
765 		ret = -EFAULT;
766 
767 	kfree(req);
768 	return ret;
769 }
770 
771 static ssize_t adb_write(struct file *file, const char __user *buf,
772 			 size_t count, loff_t *ppos)
773 {
774 	int ret/*, i*/;
775 	struct adbdev_state *state = file->private_data;
776 	struct adb_request *req;
777 
778 	if (count < 2 || count > sizeof(req->data))
779 		return -EINVAL;
780 	if (adb_controller == NULL)
781 		return -ENXIO;
782 
783 	req = kmalloc(sizeof(struct adb_request),
784 					     GFP_KERNEL);
785 	if (req == NULL)
786 		return -ENOMEM;
787 
788 	req->nbytes = count;
789 	req->done = adb_write_done;
790 	req->arg = (void *) state;
791 	req->complete = 0;
792 
793 	ret = -EFAULT;
794 	if (copy_from_user(req->data, buf, count))
795 		goto out;
796 
797 	atomic_inc(&state->n_pending);
798 
799 	/* If a probe is in progress or we are sleeping, wait for it to complete */
800 	down(&adb_probe_mutex);
801 
802 	/* Queries are special requests sent to the ADB driver itself */
803 	if (req->data[0] == ADB_QUERY) {
804 		if (count > 1)
805 			ret = do_adb_query(req);
806 		else
807 			ret = -EINVAL;
808 		up(&adb_probe_mutex);
809 	}
810 	/* Special case for ADB_BUSRESET request, all others are sent to
811 	   the controller */
812 	else if ((req->data[0] == ADB_PACKET) && (count > 1)
813 		&& (req->data[1] == ADB_BUSRESET)) {
814 		ret = do_adb_reset_bus();
815 		up(&adb_probe_mutex);
816 		atomic_dec(&state->n_pending);
817 		if (ret == 0)
818 			ret = count;
819 		goto out;
820 	} else {
821 		req->reply_expected = ((req->data[1] & 0xc) == 0xc);
822 		if (adb_controller && adb_controller->send_request)
823 			ret = adb_controller->send_request(req, 0);
824 		else
825 			ret = -ENXIO;
826 		up(&adb_probe_mutex);
827 	}
828 
829 	if (ret != 0) {
830 		atomic_dec(&state->n_pending);
831 		goto out;
832 	}
833 	return count;
834 
835 out:
836 	kfree(req);
837 	return ret;
838 }
839 
840 static const struct file_operations adb_fops = {
841 	.owner		= THIS_MODULE,
842 	.llseek		= no_llseek,
843 	.read		= adb_read,
844 	.write		= adb_write,
845 	.open		= adb_open,
846 	.release	= adb_release,
847 };
848 
849 #ifdef CONFIG_PM
850 static const struct dev_pm_ops adb_dev_pm_ops = {
851 	.suspend = adb_suspend,
852 	.resume = adb_resume,
853 	/* Hibernate hooks */
854 	.freeze = adb_freeze,
855 	.thaw = adb_resume,
856 	.poweroff = adb_poweroff,
857 	.restore = adb_resume,
858 };
859 #endif
860 
861 static struct platform_driver adb_pfdrv = {
862 	.driver = {
863 		.name = "adb",
864 #ifdef CONFIG_PM
865 		.pm = &adb_dev_pm_ops,
866 #endif
867 	},
868 };
869 
870 static struct platform_device adb_pfdev = {
871 	.name = "adb",
872 };
873 
874 static int __init
875 adb_dummy_probe(struct platform_device *dev)
876 {
877 	if (dev == &adb_pfdev)
878 		return 0;
879 	return -ENODEV;
880 }
881 
882 static void __init
883 adbdev_init(void)
884 {
885 	if (register_chrdev(ADB_MAJOR, "adb", &adb_fops)) {
886 		printk(KERN_ERR "adb: unable to get major %d\n", ADB_MAJOR);
887 		return;
888 	}
889 
890 	adb_dev_class = class_create(THIS_MODULE, "adb");
891 	if (IS_ERR(adb_dev_class))
892 		return;
893 	device_create(adb_dev_class, NULL, MKDEV(ADB_MAJOR, 0), NULL, "adb");
894 
895 	platform_device_register(&adb_pfdev);
896 	platform_driver_probe(&adb_pfdrv, adb_dummy_probe);
897 }
898