1/*
2 * drivers/uio/uio.c
3 *
4 * Copyright(C) 2005, Benedikt Spranger <b.spranger@linutronix.de>
5 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
6 * Copyright(C) 2006, Hans J. Koch <hjk@hansjkoch.de>
7 * Copyright(C) 2006, Greg Kroah-Hartman <greg@kroah.com>
8 *
9 * Userspace IO
10 *
11 * Base Functions
12 *
13 * Licensed under the GPLv2 only.
14 */
15
16#include <linux/module.h>
17#include <linux/init.h>
18#include <linux/poll.h>
19#include <linux/device.h>
20#include <linux/slab.h>
21#include <linux/mm.h>
22#include <linux/idr.h>
23#include <linux/sched.h>
24#include <linux/string.h>
25#include <linux/kobject.h>
26#include <linux/cdev.h>
27#include <linux/uio_driver.h>
28
29#define UIO_MAX_DEVICES		(1U << MINORBITS)
30
31static int uio_major;
32static struct cdev *uio_cdev;
33static DEFINE_IDR(uio_idr);
34static const struct file_operations uio_fops;
35
36/* Protect idr accesses */
37static DEFINE_MUTEX(minor_lock);
38
39/*
40 * attributes
41 */
42
43struct uio_map {
44	struct kobject kobj;
45	struct uio_mem *mem;
46};
47#define to_map(map) container_of(map, struct uio_map, kobj)
48
49static ssize_t map_name_show(struct uio_mem *mem, char *buf)
50{
51	if (unlikely(!mem->name))
52		mem->name = "";
53
54	return sprintf(buf, "%s\n", mem->name);
55}
56
57static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
58{
59	return sprintf(buf, "%pa\n", &mem->addr);
60}
61
62static ssize_t map_size_show(struct uio_mem *mem, char *buf)
63{
64	return sprintf(buf, "%pa\n", &mem->size);
65}
66
67static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
68{
69	return sprintf(buf, "0x%llx\n", (unsigned long long)mem->addr & ~PAGE_MASK);
70}
71
72struct map_sysfs_entry {
73	struct attribute attr;
74	ssize_t (*show)(struct uio_mem *, char *);
75	ssize_t (*store)(struct uio_mem *, const char *, size_t);
76};
77
78static struct map_sysfs_entry name_attribute =
79	__ATTR(name, S_IRUGO, map_name_show, NULL);
80static struct map_sysfs_entry addr_attribute =
81	__ATTR(addr, S_IRUGO, map_addr_show, NULL);
82static struct map_sysfs_entry size_attribute =
83	__ATTR(size, S_IRUGO, map_size_show, NULL);
84static struct map_sysfs_entry offset_attribute =
85	__ATTR(offset, S_IRUGO, map_offset_show, NULL);
86
87static struct attribute *attrs[] = {
88	&name_attribute.attr,
89	&addr_attribute.attr,
90	&size_attribute.attr,
91	&offset_attribute.attr,
92	NULL,	/* need to NULL terminate the list of attributes */
93};
94
95static void map_release(struct kobject *kobj)
96{
97	struct uio_map *map = to_map(kobj);
98	kfree(map);
99}
100
101static ssize_t map_type_show(struct kobject *kobj, struct attribute *attr,
102			     char *buf)
103{
104	struct uio_map *map = to_map(kobj);
105	struct uio_mem *mem = map->mem;
106	struct map_sysfs_entry *entry;
107
108	entry = container_of(attr, struct map_sysfs_entry, attr);
109
110	if (!entry->show)
111		return -EIO;
112
113	return entry->show(mem, buf);
114}
115
116static const struct sysfs_ops map_sysfs_ops = {
117	.show = map_type_show,
118};
119
120static struct kobj_type map_attr_type = {
121	.release	= map_release,
122	.sysfs_ops	= &map_sysfs_ops,
123	.default_attrs	= attrs,
124};
125
126struct uio_portio {
127	struct kobject kobj;
128	struct uio_port *port;
129};
130#define to_portio(portio) container_of(portio, struct uio_portio, kobj)
131
132static ssize_t portio_name_show(struct uio_port *port, char *buf)
133{
134	if (unlikely(!port->name))
135		port->name = "";
136
137	return sprintf(buf, "%s\n", port->name);
138}
139
140static ssize_t portio_start_show(struct uio_port *port, char *buf)
141{
142	return sprintf(buf, "0x%lx\n", port->start);
143}
144
145static ssize_t portio_size_show(struct uio_port *port, char *buf)
146{
147	return sprintf(buf, "0x%lx\n", port->size);
148}
149
150static ssize_t portio_porttype_show(struct uio_port *port, char *buf)
151{
152	const char *porttypes[] = {"none", "x86", "gpio", "other"};
153
154	if ((port->porttype < 0) || (port->porttype > UIO_PORT_OTHER))
155		return -EINVAL;
156
157	return sprintf(buf, "port_%s\n", porttypes[port->porttype]);
158}
159
160struct portio_sysfs_entry {
161	struct attribute attr;
162	ssize_t (*show)(struct uio_port *, char *);
163	ssize_t (*store)(struct uio_port *, const char *, size_t);
164};
165
166static struct portio_sysfs_entry portio_name_attribute =
167	__ATTR(name, S_IRUGO, portio_name_show, NULL);
168static struct portio_sysfs_entry portio_start_attribute =
169	__ATTR(start, S_IRUGO, portio_start_show, NULL);
170static struct portio_sysfs_entry portio_size_attribute =
171	__ATTR(size, S_IRUGO, portio_size_show, NULL);
172static struct portio_sysfs_entry portio_porttype_attribute =
173	__ATTR(porttype, S_IRUGO, portio_porttype_show, NULL);
174
175static struct attribute *portio_attrs[] = {
176	&portio_name_attribute.attr,
177	&portio_start_attribute.attr,
178	&portio_size_attribute.attr,
179	&portio_porttype_attribute.attr,
180	NULL,
181};
182
183static void portio_release(struct kobject *kobj)
184{
185	struct uio_portio *portio = to_portio(kobj);
186	kfree(portio);
187}
188
189static ssize_t portio_type_show(struct kobject *kobj, struct attribute *attr,
190			     char *buf)
191{
192	struct uio_portio *portio = to_portio(kobj);
193	struct uio_port *port = portio->port;
194	struct portio_sysfs_entry *entry;
195
196	entry = container_of(attr, struct portio_sysfs_entry, attr);
197
198	if (!entry->show)
199		return -EIO;
200
201	return entry->show(port, buf);
202}
203
204static const struct sysfs_ops portio_sysfs_ops = {
205	.show = portio_type_show,
206};
207
208static struct kobj_type portio_attr_type = {
209	.release	= portio_release,
210	.sysfs_ops	= &portio_sysfs_ops,
211	.default_attrs	= portio_attrs,
212};
213
214static ssize_t name_show(struct device *dev,
215			 struct device_attribute *attr, char *buf)
216{
217	struct uio_device *idev = dev_get_drvdata(dev);
218	return sprintf(buf, "%s\n", idev->info->name);
219}
220static DEVICE_ATTR_RO(name);
221
222static ssize_t version_show(struct device *dev,
223			    struct device_attribute *attr, char *buf)
224{
225	struct uio_device *idev = dev_get_drvdata(dev);
226	return sprintf(buf, "%s\n", idev->info->version);
227}
228static DEVICE_ATTR_RO(version);
229
230static ssize_t event_show(struct device *dev,
231			  struct device_attribute *attr, char *buf)
232{
233	struct uio_device *idev = dev_get_drvdata(dev);
234	return sprintf(buf, "%u\n", (unsigned int)atomic_read(&idev->event));
235}
236static DEVICE_ATTR_RO(event);
237
238static struct attribute *uio_attrs[] = {
239	&dev_attr_name.attr,
240	&dev_attr_version.attr,
241	&dev_attr_event.attr,
242	NULL,
243};
244ATTRIBUTE_GROUPS(uio);
245
246/* UIO class infrastructure */
247static struct class uio_class = {
248	.name = "uio",
249	.dev_groups = uio_groups,
250};
251
252/*
253 * device functions
254 */
255static int uio_dev_add_attributes(struct uio_device *idev)
256{
257	int ret;
258	int mi, pi;
259	int map_found = 0;
260	int portio_found = 0;
261	struct uio_mem *mem;
262	struct uio_map *map;
263	struct uio_port *port;
264	struct uio_portio *portio;
265
266	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
267		mem = &idev->info->mem[mi];
268		if (mem->size == 0)
269			break;
270		if (!map_found) {
271			map_found = 1;
272			idev->map_dir = kobject_create_and_add("maps",
273							&idev->dev->kobj);
274			if (!idev->map_dir)
275				goto err_map;
276		}
277		map = kzalloc(sizeof(*map), GFP_KERNEL);
278		if (!map)
279			goto err_map_kobj;
280		kobject_init(&map->kobj, &map_attr_type);
281		map->mem = mem;
282		mem->map = map;
283		ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
284		if (ret)
285			goto err_map_kobj;
286		ret = kobject_uevent(&map->kobj, KOBJ_ADD);
287		if (ret)
288			goto err_map;
289	}
290
291	for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
292		port = &idev->info->port[pi];
293		if (port->size == 0)
294			break;
295		if (!portio_found) {
296			portio_found = 1;
297			idev->portio_dir = kobject_create_and_add("portio",
298							&idev->dev->kobj);
299			if (!idev->portio_dir)
300				goto err_portio;
301		}
302		portio = kzalloc(sizeof(*portio), GFP_KERNEL);
303		if (!portio)
304			goto err_portio_kobj;
305		kobject_init(&portio->kobj, &portio_attr_type);
306		portio->port = port;
307		port->portio = portio;
308		ret = kobject_add(&portio->kobj, idev->portio_dir,
309							"port%d", pi);
310		if (ret)
311			goto err_portio_kobj;
312		ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
313		if (ret)
314			goto err_portio;
315	}
316
317	return 0;
318
319err_portio:
320	pi--;
321err_portio_kobj:
322	for (; pi >= 0; pi--) {
323		port = &idev->info->port[pi];
324		portio = port->portio;
325		kobject_put(&portio->kobj);
326	}
327	kobject_put(idev->portio_dir);
328err_map:
329	mi--;
330err_map_kobj:
331	for (; mi >= 0; mi--) {
332		mem = &idev->info->mem[mi];
333		map = mem->map;
334		kobject_put(&map->kobj);
335	}
336	kobject_put(idev->map_dir);
337	dev_err(idev->dev, "error creating sysfs files (%d)\n", ret);
338	return ret;
339}
340
341static void uio_dev_del_attributes(struct uio_device *idev)
342{
343	int i;
344	struct uio_mem *mem;
345	struct uio_port *port;
346
347	for (i = 0; i < MAX_UIO_MAPS; i++) {
348		mem = &idev->info->mem[i];
349		if (mem->size == 0)
350			break;
351		kobject_put(&mem->map->kobj);
352	}
353	kobject_put(idev->map_dir);
354
355	for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
356		port = &idev->info->port[i];
357		if (port->size == 0)
358			break;
359		kobject_put(&port->portio->kobj);
360	}
361	kobject_put(idev->portio_dir);
362}
363
364static int uio_get_minor(struct uio_device *idev)
365{
366	int retval = -ENOMEM;
367
368	mutex_lock(&minor_lock);
369	retval = idr_alloc(&uio_idr, idev, 0, UIO_MAX_DEVICES, GFP_KERNEL);
370	if (retval >= 0) {
371		idev->minor = retval;
372		retval = 0;
373	} else if (retval == -ENOSPC) {
374		dev_err(idev->dev, "too many uio devices\n");
375		retval = -EINVAL;
376	}
377	mutex_unlock(&minor_lock);
378	return retval;
379}
380
381static void uio_free_minor(struct uio_device *idev)
382{
383	mutex_lock(&minor_lock);
384	idr_remove(&uio_idr, idev->minor);
385	mutex_unlock(&minor_lock);
386}
387
388/**
389 * uio_event_notify - trigger an interrupt event
390 * @info: UIO device capabilities
391 */
392void uio_event_notify(struct uio_info *info)
393{
394	struct uio_device *idev = info->uio_dev;
395
396	atomic_inc(&idev->event);
397	wake_up_interruptible(&idev->wait);
398	kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
399}
400EXPORT_SYMBOL_GPL(uio_event_notify);
401
402/**
403 * uio_interrupt - hardware interrupt handler
404 * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
405 * @dev_id: Pointer to the devices uio_device structure
406 */
407static irqreturn_t uio_interrupt(int irq, void *dev_id)
408{
409	struct uio_device *idev = (struct uio_device *)dev_id;
410	irqreturn_t ret = idev->info->handler(irq, idev->info);
411
412	if (ret == IRQ_HANDLED)
413		uio_event_notify(idev->info);
414
415	return ret;
416}
417
418struct uio_listener {
419	struct uio_device *dev;
420	s32 event_count;
421};
422
423static int uio_open(struct inode *inode, struct file *filep)
424{
425	struct uio_device *idev;
426	struct uio_listener *listener;
427	int ret = 0;
428
429	mutex_lock(&minor_lock);
430	idev = idr_find(&uio_idr, iminor(inode));
431	mutex_unlock(&minor_lock);
432	if (!idev) {
433		ret = -ENODEV;
434		goto out;
435	}
436
437	if (!try_module_get(idev->owner)) {
438		ret = -ENODEV;
439		goto out;
440	}
441
442	listener = kmalloc(sizeof(*listener), GFP_KERNEL);
443	if (!listener) {
444		ret = -ENOMEM;
445		goto err_alloc_listener;
446	}
447
448	listener->dev = idev;
449	listener->event_count = atomic_read(&idev->event);
450	filep->private_data = listener;
451
452	if (idev->info->open) {
453		ret = idev->info->open(idev->info, inode);
454		if (ret)
455			goto err_infoopen;
456	}
457	return 0;
458
459err_infoopen:
460	kfree(listener);
461
462err_alloc_listener:
463	module_put(idev->owner);
464
465out:
466	return ret;
467}
468
469static int uio_fasync(int fd, struct file *filep, int on)
470{
471	struct uio_listener *listener = filep->private_data;
472	struct uio_device *idev = listener->dev;
473
474	return fasync_helper(fd, filep, on, &idev->async_queue);
475}
476
477static int uio_release(struct inode *inode, struct file *filep)
478{
479	int ret = 0;
480	struct uio_listener *listener = filep->private_data;
481	struct uio_device *idev = listener->dev;
482
483	if (idev->info->release)
484		ret = idev->info->release(idev->info, inode);
485
486	module_put(idev->owner);
487	kfree(listener);
488	return ret;
489}
490
491static unsigned int uio_poll(struct file *filep, poll_table *wait)
492{
493	struct uio_listener *listener = filep->private_data;
494	struct uio_device *idev = listener->dev;
495
496	if (!idev->info->irq)
497		return -EIO;
498
499	poll_wait(filep, &idev->wait, wait);
500	if (listener->event_count != atomic_read(&idev->event))
501		return POLLIN | POLLRDNORM;
502	return 0;
503}
504
505static ssize_t uio_read(struct file *filep, char __user *buf,
506			size_t count, loff_t *ppos)
507{
508	struct uio_listener *listener = filep->private_data;
509	struct uio_device *idev = listener->dev;
510	DECLARE_WAITQUEUE(wait, current);
511	ssize_t retval;
512	s32 event_count;
513
514	if (!idev->info->irq)
515		return -EIO;
516
517	if (count != sizeof(s32))
518		return -EINVAL;
519
520	add_wait_queue(&idev->wait, &wait);
521
522	do {
523		set_current_state(TASK_INTERRUPTIBLE);
524
525		event_count = atomic_read(&idev->event);
526		if (event_count != listener->event_count) {
527			__set_current_state(TASK_RUNNING);
528			if (copy_to_user(buf, &event_count, count))
529				retval = -EFAULT;
530			else {
531				listener->event_count = event_count;
532				retval = count;
533			}
534			break;
535		}
536
537		if (filep->f_flags & O_NONBLOCK) {
538			retval = -EAGAIN;
539			break;
540		}
541
542		if (signal_pending(current)) {
543			retval = -ERESTARTSYS;
544			break;
545		}
546		schedule();
547	} while (1);
548
549	__set_current_state(TASK_RUNNING);
550	remove_wait_queue(&idev->wait, &wait);
551
552	return retval;
553}
554
555static ssize_t uio_write(struct file *filep, const char __user *buf,
556			size_t count, loff_t *ppos)
557{
558	struct uio_listener *listener = filep->private_data;
559	struct uio_device *idev = listener->dev;
560	ssize_t retval;
561	s32 irq_on;
562
563	if (!idev->info->irq)
564		return -EIO;
565
566	if (count != sizeof(s32))
567		return -EINVAL;
568
569	if (!idev->info->irqcontrol)
570		return -ENOSYS;
571
572	if (copy_from_user(&irq_on, buf, count))
573		return -EFAULT;
574
575	retval = idev->info->irqcontrol(idev->info, irq_on);
576
577	return retval ? retval : sizeof(s32);
578}
579
580static int uio_find_mem_index(struct vm_area_struct *vma)
581{
582	struct uio_device *idev = vma->vm_private_data;
583
584	if (vma->vm_pgoff < MAX_UIO_MAPS) {
585		if (idev->info->mem[vma->vm_pgoff].size == 0)
586			return -1;
587		return (int)vma->vm_pgoff;
588	}
589	return -1;
590}
591
592static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
593{
594	struct uio_device *idev = vma->vm_private_data;
595	struct page *page;
596	unsigned long offset;
597	void *addr;
598
599	int mi = uio_find_mem_index(vma);
600	if (mi < 0)
601		return VM_FAULT_SIGBUS;
602
603	/*
604	 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
605	 * to use mem[N].
606	 */
607	offset = (vmf->pgoff - mi) << PAGE_SHIFT;
608
609	addr = (void *)(unsigned long)idev->info->mem[mi].addr + offset;
610	if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
611		page = virt_to_page(addr);
612	else
613		page = vmalloc_to_page(addr);
614	get_page(page);
615	vmf->page = page;
616	return 0;
617}
618
619static const struct vm_operations_struct uio_logical_vm_ops = {
620	.fault = uio_vma_fault,
621};
622
623static int uio_mmap_logical(struct vm_area_struct *vma)
624{
625	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
626	vma->vm_ops = &uio_logical_vm_ops;
627	return 0;
628}
629
630static const struct vm_operations_struct uio_physical_vm_ops = {
631#ifdef CONFIG_HAVE_IOREMAP_PROT
632	.access = generic_access_phys,
633#endif
634};
635
636static int uio_mmap_physical(struct vm_area_struct *vma)
637{
638	struct uio_device *idev = vma->vm_private_data;
639	int mi = uio_find_mem_index(vma);
640	struct uio_mem *mem;
641	if (mi < 0)
642		return -EINVAL;
643	mem = idev->info->mem + mi;
644
645	if (mem->addr & ~PAGE_MASK)
646		return -ENODEV;
647	if (vma->vm_end - vma->vm_start > mem->size)
648		return -EINVAL;
649
650	vma->vm_ops = &uio_physical_vm_ops;
651	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
652
653	/*
654	 * We cannot use the vm_iomap_memory() helper here,
655	 * because vma->vm_pgoff is the map index we looked
656	 * up above in uio_find_mem_index(), rather than an
657	 * actual page offset into the mmap.
658	 *
659	 * So we just do the physical mmap without a page
660	 * offset.
661	 */
662	return remap_pfn_range(vma,
663			       vma->vm_start,
664			       mem->addr >> PAGE_SHIFT,
665			       vma->vm_end - vma->vm_start,
666			       vma->vm_page_prot);
667}
668
669static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
670{
671	struct uio_listener *listener = filep->private_data;
672	struct uio_device *idev = listener->dev;
673	int mi;
674	unsigned long requested_pages, actual_pages;
675	int ret = 0;
676
677	if (vma->vm_end < vma->vm_start)
678		return -EINVAL;
679
680	vma->vm_private_data = idev;
681
682	mi = uio_find_mem_index(vma);
683	if (mi < 0)
684		return -EINVAL;
685
686	requested_pages = vma_pages(vma);
687	actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
688			+ idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
689	if (requested_pages > actual_pages)
690		return -EINVAL;
691
692	if (idev->info->mmap) {
693		ret = idev->info->mmap(idev->info, vma);
694		return ret;
695	}
696
697	switch (idev->info->mem[mi].memtype) {
698		case UIO_MEM_PHYS:
699			return uio_mmap_physical(vma);
700		case UIO_MEM_LOGICAL:
701		case UIO_MEM_VIRTUAL:
702			return uio_mmap_logical(vma);
703		default:
704			return -EINVAL;
705	}
706}
707
708static const struct file_operations uio_fops = {
709	.owner		= THIS_MODULE,
710	.open		= uio_open,
711	.release	= uio_release,
712	.read		= uio_read,
713	.write		= uio_write,
714	.mmap		= uio_mmap,
715	.poll		= uio_poll,
716	.fasync		= uio_fasync,
717	.llseek		= noop_llseek,
718};
719
720static int uio_major_init(void)
721{
722	static const char name[] = "uio";
723	struct cdev *cdev = NULL;
724	dev_t uio_dev = 0;
725	int result;
726
727	result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name);
728	if (result)
729		goto out;
730
731	result = -ENOMEM;
732	cdev = cdev_alloc();
733	if (!cdev)
734		goto out_unregister;
735
736	cdev->owner = THIS_MODULE;
737	cdev->ops = &uio_fops;
738	kobject_set_name(&cdev->kobj, "%s", name);
739
740	result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES);
741	if (result)
742		goto out_put;
743
744	uio_major = MAJOR(uio_dev);
745	uio_cdev = cdev;
746	return 0;
747out_put:
748	kobject_put(&cdev->kobj);
749out_unregister:
750	unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
751out:
752	return result;
753}
754
755static void uio_major_cleanup(void)
756{
757	unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
758	cdev_del(uio_cdev);
759}
760
761static int init_uio_class(void)
762{
763	int ret;
764
765	/* This is the first time in here, set everything up properly */
766	ret = uio_major_init();
767	if (ret)
768		goto exit;
769
770	ret = class_register(&uio_class);
771	if (ret) {
772		printk(KERN_ERR "class_register failed for uio\n");
773		goto err_class_register;
774	}
775	return 0;
776
777err_class_register:
778	uio_major_cleanup();
779exit:
780	return ret;
781}
782
783static void release_uio_class(void)
784{
785	class_unregister(&uio_class);
786	uio_major_cleanup();
787}
788
789/**
790 * uio_register_device - register a new userspace IO device
791 * @owner:	module that creates the new device
792 * @parent:	parent device
793 * @info:	UIO device capabilities
794 *
795 * returns zero on success or a negative error code.
796 */
797int __uio_register_device(struct module *owner,
798			  struct device *parent,
799			  struct uio_info *info)
800{
801	struct uio_device *idev;
802	int ret = 0;
803
804	if (!parent || !info || !info->name || !info->version)
805		return -EINVAL;
806
807	info->uio_dev = NULL;
808
809	idev = devm_kzalloc(parent, sizeof(*idev), GFP_KERNEL);
810	if (!idev) {
811		return -ENOMEM;
812	}
813
814	idev->owner = owner;
815	idev->info = info;
816	init_waitqueue_head(&idev->wait);
817	atomic_set(&idev->event, 0);
818
819	ret = uio_get_minor(idev);
820	if (ret)
821		return ret;
822
823	idev->dev = device_create(&uio_class, parent,
824				  MKDEV(uio_major, idev->minor), idev,
825				  "uio%d", idev->minor);
826	if (IS_ERR(idev->dev)) {
827		printk(KERN_ERR "UIO: device register failed\n");
828		ret = PTR_ERR(idev->dev);
829		goto err_device_create;
830	}
831
832	ret = uio_dev_add_attributes(idev);
833	if (ret)
834		goto err_uio_dev_add_attributes;
835
836	info->uio_dev = idev;
837
838	if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) {
839		/*
840		 * Note that we deliberately don't use devm_request_irq
841		 * here. The parent module can unregister the UIO device
842		 * and call pci_disable_msi, which requires that this
843		 * irq has been freed. However, the device may have open
844		 * FDs at the time of unregister and therefore may not be
845		 * freed until they are released.
846		 */
847		ret = request_irq(info->irq, uio_interrupt,
848				  info->irq_flags, info->name, idev);
849		if (ret)
850			goto err_request_irq;
851	}
852
853	return 0;
854
855err_request_irq:
856	uio_dev_del_attributes(idev);
857err_uio_dev_add_attributes:
858	device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
859err_device_create:
860	uio_free_minor(idev);
861	return ret;
862}
863EXPORT_SYMBOL_GPL(__uio_register_device);
864
865/**
866 * uio_unregister_device - unregister a industrial IO device
867 * @info:	UIO device capabilities
868 *
869 */
870void uio_unregister_device(struct uio_info *info)
871{
872	struct uio_device *idev;
873
874	if (!info || !info->uio_dev)
875		return;
876
877	idev = info->uio_dev;
878
879	uio_free_minor(idev);
880
881	uio_dev_del_attributes(idev);
882
883	if (info->irq && info->irq != UIO_IRQ_CUSTOM)
884		free_irq(info->irq, idev);
885
886	device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
887
888	return;
889}
890EXPORT_SYMBOL_GPL(uio_unregister_device);
891
892static int __init uio_init(void)
893{
894	return init_uio_class();
895}
896
897static void __exit uio_exit(void)
898{
899	release_uio_class();
900	idr_destroy(&uio_idr);
901}
902
903module_init(uio_init)
904module_exit(uio_exit)
905MODULE_LICENSE("GPL v2");
906