aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/uio/uio.c
blob: bff1afbde5a4b0ad01d0314b1661d43c972c3d84 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
/*
 * drivers/uio/uio.c
 *
 * Copyright(C) 2005, Benedikt Spranger <b.spranger@linutronix.de>
 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
 * Copyright(C) 2006, Hans J. Koch <hjk@linutronix.de>
 * Copyright(C) 2006, Greg Kroah-Hartman <greg@kroah.com>
 *
 * Userspace IO
 *
 * Base Functions
 *
 * Licensed under the GPLv2 only.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/idr.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/kobject.h>
#include <linux/uio_driver.h>

#define UIO_MAX_DEVICES 255

struct uio_device {
	struct module		*owner;
	struct device		*dev;
	int			minor;
	atomic_t		event;
	struct fasync_struct	*async_queue;
	wait_queue_head_t	wait;
	int			vma_count;
	struct uio_info		*info;
	struct kobject		*map_dir;
	struct kobject		*portio_dir;
};

static int uio_major;
static DEFINE_IDR(uio_idr);
static const struct file_operations uio_fops;

/* UIO class infrastructure */
static struct uio_class {
	struct kref kref;
	struct class *class;
} *uio_class;

/* Protect idr accesses */
static DEFINE_MUTEX(minor_lock);

/*
 * attributes
 */

struct uio_map {
	struct kobject kobj;
	struct uio_mem *mem;
};
#define to_map(map) container_of(map, struct uio_map, kobj)

static ssize_t map_name_show(struct uio_mem *mem, char *buf)
{
	if (unlikely(!mem->name))
		mem->name = "";

	return sprintf(buf, "%s\n", mem->name);
}

static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
{
	return sprintf(buf, "0x%lx\n", mem->addr);
}

static ssize_t map_size_show(struct uio_mem *mem, char *buf)
{
	return sprintf(buf, "0x%lx\n", mem->size);
}

static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
{
	return sprintf(buf, "0x%lx\n", mem->addr & ~PAGE_MASK);
}

struct map_sysfs_entry {
	struct attribute attr;
	ssize_t (*show)(struct uio_mem *, char *);
	ssize_t (*store)(struct uio_mem *, const char *, size_t);
};

static struct map_sysfs_entry name_attribute =
	__ATTR(name, S_IRUGO, map_name_show, NULL);
static struct map_sysfs_entry addr_attribute =
	__ATTR(addr, S_IRUGO, map_addr_show, NULL);
static struct map_sysfs_entry size_attribute =
	__ATTR(size, S_IRUGO, map_size_show, NULL);
static struct map_sysfs_entry offset_attribute =
	__ATTR(offset, S_IRUGO, map_offset_show, NULL);

static struct attribute *attrs[] = {
	&name_attribute.attr,
	&addr_attribute.attr,
	&size_attribute.attr,
	&offset_attribute.attr,
	NULL,	/* need to NULL terminate the list of attributes */
};

static void map_release(struct kobject *kobj)
{
	struct uio_map *map = to_map(kobj);
	kfree(map);
}

static ssize_t map_type_show(struct kobject *kobj, struct attribute *attr,
			     char *buf)
{
	struct uio_map *map = to_map(kobj);
	struct uio_mem *mem = map->mem;
	struct map_sysfs_entry *entry;

	entry = container_of(attr, struct map_sysfs_entry, attr);

	if (!entry->show)
		return -EIO;

	return entry->show(mem, buf);
}

static const struct sysfs_ops map_sysfs_ops = {
	.show = map_type_show,
};

static struct kobj_type map_attr_type = {
	.release	= map_release,
	.sysfs_ops	= &map_sysfs_ops,
	.default_attrs	= attrs,
};

struct uio_portio {
	struct kobject kobj;
	struct uio_port *port;
};
#define to_portio(portio) container_of(portio, struct uio_portio, kobj)

static ssize_t portio_name_show(struct uio_port *port, char *buf)
{
	if (unlikely(!port->name))
		port->name = "";

	return sprintf(buf, "%s\n", port->name);
}

static ssize_t portio_start_show(struct uio_port *port, char *buf)
{
	return sprintf(buf, "0x%lx\n", port->start);
}

static ssize_t portio_size_show(struct uio_port *port, char *buf)
{
	return sprintf(buf, "0x%lx\n", port->size);
}

static ssize_t portio_porttype_show(struct uio_port *port, char *buf)
{
	const char *porttypes[] = {"none", "x86", "gpio", "other"};

	if ((port->porttype < 0) || (port->porttype > UIO_PORT_OTHER))
		return -EINVAL;

	return sprintf(buf, "port_%s\n", porttypes[port->porttype]);
}

struct portio_sysfs_entry {
	struct attribute attr;
	ssize_t (*show)(struct uio_port *, char *);
	ssize_t (*store)(struct uio_port *, const char *, size_t);
};

static struct portio_sysfs_entry portio_name_attribute =
	__ATTR(name, S_IRUGO, portio_name_show, NULL);
static struct portio_sysfs_entry portio_start_attribute =
	__ATTR(start, S_IRUGO, portio_start_show, NULL);
static struct portio_sysfs_entry portio_size_attribute =
	__ATTR(size, S_IRUGO, portio_size_show, NULL);
static struct portio_sysfs_entry portio_porttype_attribute =
	__ATTR(porttype, S_IRUGO, portio_porttype_show, NULL);

static struct attribute *portio_attrs[] = {
	&portio_name_attribute.attr,
	&portio_start_attribute.attr,
	&portio_size_attribute.attr,
	&portio_porttype_attribute.attr,
	NULL,
};

static void portio_release(struct kobject *kobj)
{
	struct uio_portio *portio = to_portio(kobj);
	kfree(portio);
}

static ssize_t portio_type_show(struct kobject *kobj, struct attribute *attr,
			     char *buf)
{
	struct uio_portio *portio = to_portio(kobj);
	struct uio_port *port = portio->port;
	struct portio_sysfs_entry *entry;

	entry = container_of(attr, struct portio_sysfs_entry, attr);

	if (!entry->show)
		return -EIO;

	return entry->show(port, buf);
}

static const struct sysfs_ops portio_sysfs_ops = {
	.show = portio_type_show,
};

static struct kobj_type portio_attr_type = {
	.release	= portio_release,
	.sysfs_ops	= &portio_sysfs_ops,
	.default_attrs	= portio_attrs,
};

static ssize_t show_name(struct device *dev,
			 struct device_attribute *attr, char *buf)
{
	struct uio_device *idev = dev_get_drvdata(dev);
	if (idev)
		return sprintf(buf, "%s\n", idev->info->name);
	else
		return -ENODEV;
}
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

static ssize_t show_version(struct device *dev,
			    struct device_attribute *attr, char *buf)
{
	struct uio_device *idev = dev_get_drvdata(dev);
	if (idev)
		return sprintf(buf, "%s\n", idev->info->version);
	else
		return -ENODEV;
}
static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);

static ssize_t show_event(struct device *dev,
			  struct device_attribute *attr, char *buf)
{
	struct uio_device *idev = dev_get_drvdata(dev);
	if (idev)
		return sprintf(buf, "%u\n",
				(unsigned int)atomic_read(&idev->event));
	else
		return -ENODEV;
}
static DEVICE_ATTR(event, S_IRUGO, show_event, NULL);

static struct attribute *uio_attrs[] = {
	&dev_attr_name.attr,
	&dev_attr_version.attr,
	&dev_attr_event.attr,
	NULL,
};

static struct attribute_group uio_attr_grp = {
	.attrs = uio_attrs,
};

/*
 * device functions
 */
static int uio_dev_add_attributes(struct uio_device *idev)
{
	int ret;
	int mi, pi;
	int map_found = 0;
	int portio_found = 0;
	struct uio_mem *mem;
	struct uio_map *map;
	struct uio_port *port;
	struct uio_portio *portio;

	ret = sysfs_create_group(&idev->dev->kobj, &uio_attr_grp);
	if (ret)
		goto err_group;

	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
		mem = &idev->info->mem[mi];
		if (mem->size == 0)
			break;
		if (!map_found) {
			map_found = 1;
			idev->map_dir = kobject_create_and_add("maps",
							&idev->dev->kobj);
			if (!idev->map_dir)
				goto err_map;
		}
		map = kzalloc(sizeof(*map), GFP_KERNEL);
		if (!map)
			goto err_map;
		kobject_init(&map->kobj, &map_attr_type);
		map->mem = mem;
		mem->map = map;
		ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
		if (ret)
			goto err_map;
		ret = kobject_uevent(&map->kobj, KOBJ_ADD);
		if (ret)
			goto err_map;
	}

	for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
		port = &idev->info->port[pi];
		if (port->size == 0)
			break;
		if (!portio_found) {
			portio_found = 1;
			idev->portio_dir = kobject_create_and_add("portio",
							&idev->dev->kobj);
			if (!idev->portio_dir)
				goto err_portio;
		}
		portio = kzalloc(sizeof(*portio), GFP_KERNEL);
		if (!portio)
			goto err_portio;
		kobject_init(&portio->kobj, &portio_attr_type);
		portio->port = port;
		port->portio = portio;
		ret = kobject_add(&portio->kobj, idev->portio_dir,
							"port%d", pi);
		if (ret)
			goto err_portio;
		ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
		if (ret)
			goto err_portio;
	}

	return 0;

err_portio:
	for (pi--; pi >= 0; pi--) {
		port = &idev->info->port[pi];
		portio = port->portio;
		kobject_put(&portio->kobj);
	}
	kobject_put(idev->portio_dir);
err_map:
	for (mi--; mi>=0; mi--) {
		mem = &idev->info->mem[mi];
		map = mem->map;
		kobject_put(&map->kobj);
	}
	kobject_put(idev->map_dir);
	sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
err_group:
	dev_err(idev->dev, "error creating sysfs files (%d)\n", ret);
	return ret;
}

static void uio_dev_del_attributes(struct uio_device *idev)
{
	int i;
	struct uio_mem *mem;
	struct uio_port *port;

	for (i = 0; i < MAX_UIO_MAPS; i++) {
		mem = &idev->info->mem[i];
		if (mem->size == 0)
			break;
		kobject_put(&mem->map->kobj);
	}
	kobject_put(idev->map_dir);

	for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
		port = &idev->info->port[i];
		if (port->size == 0)
			break;
		kobject_put(&port->portio->kobj);
	}
	kobject_put(idev->portio_dir);

	sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
}

static int uio_get_minor(struct uio_device *idev)
{
	int retval = -ENOMEM;
	int id;

	mutex_lock(&minor_lock);
	if (idr_pre_get(&uio_idr, GFP_KERNEL) == 0)
		goto exit;

	retval = idr_get_new(&uio_idr, idev, &id);
	if (retval < 0) {
		if (retval == -EAGAIN)
			retval = -ENOMEM;
		goto exit;
	}
	idev->minor = id & MAX_ID_MASK;
exit:
	mutex_unlock(&minor_lock);
	return retval;
}

static void uio_free_minor(struct uio_device *idev)
{
	mutex_lock(&minor_lock);
	idr_remove(&uio_idr, idev->minor);
	mutex_unlock(&minor_lock);
}

/**
 * uio_event_notify - trigger an interrupt event
 * @info: UIO device capabilities
 */
void uio_event_notify(struct uio_info *info)
{
	struct uio_device *idev = info->uio_dev;

	atomic_inc(&idev->event);
	wake_up_interruptible(&idev->wait);
	kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
}
EXPORT_SYMBOL_GPL(uio_event_notify);

/**
 * uio_interrupt - hardware interrupt handler
 * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
 * @dev_id: Pointer to the devices uio_device structure
 */
static irqreturn_t uio_interrupt(int irq, void *dev_id)
{
	struct uio_device *idev = (struct uio_device *)dev_id;
	irqreturn_t ret = idev->info->handler(irq, idev->info);

	if (ret == IRQ_HANDLED)
		uio_event_notify(idev->info);

	return ret;
}

struct uio_listener {
	struct uio_device *dev;
	s32 event_count;
};

static int uio_open(struct inode *inode, struct file *filep)
{
	struct uio_device *idev;
	struct uio_listener *listener;
	int ret = 0;

	mutex_lock(&minor_lock);
	idev = idr_find(&uio_idr, iminor(inode));
	mutex_unlock(&minor_lock);
	if (!idev) {
		ret = -ENODEV;
		goto out;
	}

	if (!try_module_get(idev->owner)) {
		ret = -ENODEV;
		goto out;
	}

	listener = kmalloc(sizeof(*listener), GFP_KERNEL);
	if (!listener) {
		ret = -ENOMEM;
		goto err_alloc_listener;
	}

	listener->dev = idev;
	listener->event_count = atomic_read(&idev->event);
	filep->private_data = listener;

	if (idev->info->open) {
		ret = idev->info->open(idev->info, inode);
		if (ret)
			goto err_infoopen;
	}
	return 0;

err_infoopen:
	kfree(listener);

err_alloc_listener:
	module_put(idev->owner);

out:
	return ret;
}

static int uio_fasync(int fd, struct file *filep, int on)
{
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;

	return fasync_helper(fd, filep, on, &idev->async_queue);
}

static int uio_release(struct inode *inode, struct file *filep)
{
	int ret = 0;
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;

	if (idev->info->release)
		ret = idev->info->release(idev->info, inode);

	module_put(idev->owner);
	kfree(listener);
	return ret;
}

static unsigned int uio_poll(struct file *filep, poll_table *wait)
{
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;

	if (idev->info->irq == UIO_IRQ_NONE)
		return -EIO;

	poll_wait(filep, &idev->wait, wait);
	if (listener->event_count != atomic_read(&idev->event))
		return POLLIN | POLLRDNORM;
	return 0;
}

static ssize_t uio_read(struct file *filep, char __user *buf,
			size_t count, loff_t *ppos)
{
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;
	DECLARE_WAITQUEUE(wait, current);
	ssize_t retval;
	s32 event_count;

	if (idev->info->irq == UIO_IRQ_NONE)
		return -EIO;

	if (count != sizeof(s32))
		return -EINVAL;

	add_wait_queue(&idev->wait, &wait);

	do {
		set_current_state(TASK_INTERRUPTIBLE);

		event_count = atomic_read(&idev->event);
		if (event_count != listener->event_count) {
			if (copy_to_user(buf, &event_count, count))
				retval = -EFAULT;
			else {
				listener->event_count = event_count;
				retval = count;
			}
			break;
		}

		if (filep->f_flags & O_NONBLOCK) {
			retval = -EAGAIN;
			break;
		}

		if (signal_pending(current)) {
			retval = -ERESTARTSYS;
			break;
		}
		schedule();
	} while (1);

	__set_current_state(TASK_RUNNING);
	remove_wait_queue(&idev->wait, &wait);

	return retval;
}

static ssize_t uio_write(struct file *filep, const char __user *buf,
			size_t count, loff_t *ppos)
{
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;
	ssize_t retval;
	s32 irq_on;

	if (idev->info->irq == UIO_IRQ_NONE)
		return -EIO;

	if (count != sizeof(s32))
		return -EINVAL;

	if (!idev->info->irqcontrol)
		return -ENOSYS;

	if (copy_from_user(&irq_on, buf, count))
		return -EFAULT;

	retval = idev->info->irqcontrol(idev->info, irq_on);

	return retval ? retval : sizeof(s32);
}

static int uio_find_mem_index(struct vm_area_struct *vma)
{
	int mi;
	struct uio_device *idev = vma->vm_private_data;

	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
		if (idev->info->mem[mi].size == 0)
			return -1;
		if (vma->vm_pgoff == mi)
			return mi;
	}
	return -1;
}

static void uio_vma_open(struct vm_area_struct *vma)
{
	struct uio_device *idev = vma->vm_private_data;
	idev->vma_count++;
}

static void uio_vma_close(struct vm_area_struct *vma)
{
	struct uio_device *idev = vma->vm_private_data;
	idev->vma_count--;
}

static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct uio_device *idev = vma->vm_private_data;
	struct page *page;
	unsigned long offset;

	int mi = uio_find_mem_index(vma);
	if (mi < 0)
		return VM_FAULT_SIGBUS;

	/*
	 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
	 * to use mem[N].
	 */
	offset = (vmf->pgoff - mi) << PAGE_SHIFT;

	if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
		page = virt_to_page(idev->info->mem[mi].addr + offset);
	else
		page = vmalloc_to_page((void *)idev->info->mem[mi].addr
							+ offset);
	get_page(page);
	vmf->page = page;
	return 0;
}

static const struct vm_operations_struct uio_vm_ops = {
	.open = uio_vma_open,
	.close = uio_vma_close,
	.fault = uio_vma_fault,
};

static int uio_mmap_physical(struct vm_area_struct *vma)
{
	struct uio_device *idev = vma->vm_private_data;
	int mi = uio_find_mem_index(vma);
	if (mi < 0)
		return -EINVAL;

	vma->vm_flags |= VM_IO | VM_RESERVED;

	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	return remap_pfn_range(vma,
			       vma->vm_start,
			       idev->info->mem[mi].addr >> PAGE_SHIFT,
			       vma->vm_end - vma->vm_start,
			       vma->vm_page_prot);
}

static int uio_mmap_logical(struct vm_area_struct *vma)
{
	vma->vm_flags |= VM_RESERVED;
	vma->vm_ops = &uio_vm_ops;
	uio_vma_open(vma);
	return 0;
}

static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
{
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;
	int mi;
	unsigned long requested_pages, actual_pages;
	int ret = 0;

	if (vma->vm_end < vma->vm_start)
		return -EINVAL;

	vma->vm_private_data = idev;

	mi = uio_find_mem_index(vma);
	if (mi < 0)
		return -EINVAL;

	requested_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
	actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
			+ idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
	if (requested_pages > actual_pages)
		return -EINVAL;

	if (idev->info->mmap) {
		ret = idev->info->mmap(idev->info, vma);
		return ret;
	}

	switch (idev->info->mem[mi].memtype) {
		case UIO_MEM_PHYS:
			return uio_mmap_physical(vma);
		case UIO_MEM_LOGICAL:
		case UIO_MEM_VIRTUAL:
			return uio_mmap_logical(vma);
		default:
			return -EINVAL;
	}
}

static const struct file_operations uio_fops = {
	.owner		= THIS_MODULE,
	.open		= uio_open,
	.release	= uio_release,
	.read		= uio_read,
	.write		= uio_write,
	.mmap		= uio_mmap,
	.poll		= uio_poll,
	.fasync		= uio_fasync,
};

static int uio_major_init(void)
{
	uio_major = register_chrdev(0, "uio", &uio_fops);
	if (uio_major < 0)
		return uio_major;
	return 0;
}

static void uio_major_cleanup(void)
{
	unregister_chrdev(uio_major, "uio");
}

static int init_uio_class(void)
{
	int ret = 0;

	if (uio_class != NULL) {
		kref_get(&uio_class->kref);
		goto exit;
	}

	/* This is the first time in here, set everything up properly */
	ret = uio_major_init();
	if (ret)
		goto exit;

	uio_class = kzalloc(sizeof(*uio_class), GFP_KERNEL);
	if (!uio_class) {
		ret = -ENOMEM;
		goto err_kzalloc;
	}

	kref_init(&uio_class->kref);
	uio_class->class = class_create(THIS_MODULE, "uio");
	if (IS_ERR(uio_class->class)) {
		ret = IS_ERR(uio_class->class);
		printk(KERN_ERR "class_create failed for uio\n");
		goto err_class_create;
	}
	return 0;

err_class_create:
	kfree(uio_class);
	uio_class = NULL;
err_kzalloc:
	uio_major_cleanup();
exit:
	return ret;
}

static void release_uio_class(struct kref *kref)
{
	/* Ok, we cheat as we know we only have one uio_class */
	class_destroy(uio_class->class);
	kfree(uio_class);
	uio_major_cleanup();
	uio_class = NULL;
}

static void uio_class_destroy(void)
{
	if (uio_class)
		kref_put(&uio_class->kref, release_uio_class);
}

/**
 * uio_register_device - register a new userspace IO device
 * @owner:	module that creates the new device
 * @parent:	parent device
 * @info:	UIO device capabilities
 *
 * returns zero on success or a negative error code.
 */
int __uio_register_device(struct module *owner,
			  struct device *parent,
			  struct uio_info *info)
{
	struct uio_device *idev;
	int ret = 0;

	if (!parent || !info || !info->name || !info->version)
		return -EINVAL;

	info->uio_dev = NULL;

	ret = init_uio_class();
	if (ret)
		return ret;

	idev = kzalloc(sizeof(*idev), GFP_KERNEL);
	if (!idev) {
		ret = -ENOMEM;
		goto err_kzalloc;
	}

	idev->owner = owner;
	idev->info = info;
	init_waitqueue_head(&idev->wait);
	atomic_set(&idev->event, 0);

	ret = uio_get_minor(idev);
	if (ret)
		goto err_get_minor;

	idev->dev = device_create(uio_class->class, parent,
				  MKDEV(uio_major, idev->minor), idev,
				  "uio%d", idev->minor);
	if (IS_ERR(idev->dev)) {
		printk(KERN_ERR "UIO: device register failed\n");
		ret = PTR_ERR(idev->dev);
		goto err_device_create;
	}

	ret = uio_dev_add_attributes(idev);
	if (ret)
		goto err_uio_dev_add_attributes;

	info->uio_dev = idev;

	if (idev->info->irq >= 0) {
		ret = request_irq(idev->info->irq, uio_interrupt,
				  idev->info->irq_flags, idev->info->name, idev);
		if (ret)
			goto err_request_irq;
	}

	return 0;

err_request_irq:
	uio_dev_del_attributes(idev);
err_uio_dev_add_attributes:
	device_destroy(uio_class->class, MKDEV(uio_major, idev->minor));
err_device_create:
	uio_free_minor(idev);
err_get_minor:
	kfree(idev);
err_kzalloc:
	uio_class_destroy();
	return ret;
}
EXPORT_SYMBOL_GPL(__uio_register_device);

/**
 * uio_unregister_device - unregister a industrial IO device
 * @info:	UIO device capabilities
 *
 */
void uio_unregister_device(struct uio_info *info)
{
	struct uio_device *idev;

	if (!info || !info->uio_dev)
		return;

	idev = info->uio_dev;

	uio_free_minor(idev);

	if (info->irq >= 0)
		free_irq(info->irq, idev);

	uio_dev_del_attributes(idev);

	dev_set_drvdata(idev->dev, NULL);
	device_destroy(uio_class->class, MKDEV(uio_major, idev->minor));
	kfree(idev);
	uio_class_destroy();

	return;
}
EXPORT_SYMBOL_GPL(uio_unregister_device);

static int __init uio_init(void)
{
	return 0;
}

static void __exit uio_exit(void)
{
}

module_init(uio_init)
module_exit(uio_exit)
MODULE_LICENSE("GPL v2");