xref: /linux/drivers/uio/uio.c (revision f3539c12d8196ce0a1993364d30b3a18908470d1) 
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 
31 static int uio_major;
32 static struct cdev *uio_cdev;
33 static DEFINE_IDR(uio_idr);
34 static const struct file_operations uio_fops;
35 
36 /* Protect idr accesses */
37 static DEFINE_MUTEX(minor_lock);
38 
39 /*
40  * attributes
41  */
42 
43 struct 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 
49 static 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 
57 static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
58 {
59 	return sprintf(buf, "%pa\n", &mem->addr);
60 }
61 
62 static ssize_t map_size_show(struct uio_mem *mem, char *buf)
63 {
64 	return sprintf(buf, "%pa\n", &mem->size);
65 }
66 
67 static 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 
72 struct 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 
78 static struct map_sysfs_entry name_attribute =
79 	__ATTR(name, S_IRUGO, map_name_show, NULL);
80 static struct map_sysfs_entry addr_attribute =
81 	__ATTR(addr, S_IRUGO, map_addr_show, NULL);
82 static struct map_sysfs_entry size_attribute =
83 	__ATTR(size, S_IRUGO, map_size_show, NULL);
84 static struct map_sysfs_entry offset_attribute =
85 	__ATTR(offset, S_IRUGO, map_offset_show, NULL);
86 
87 static 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 
95 static void map_release(struct kobject *kobj)
96 {
97 	struct uio_map *map = to_map(kobj);
98 	kfree(map);
99 }
100 
101 static 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 
116 static const struct sysfs_ops map_sysfs_ops = {
117 	.show = map_type_show,
118 };
119 
120 static struct kobj_type map_attr_type = {
121 	.release	= map_release,
122 	.sysfs_ops	= &map_sysfs_ops,
123 	.default_attrs	= attrs,
124 };
125 
126 struct 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 
132 static 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 
140 static ssize_t portio_start_show(struct uio_port *port, char *buf)
141 {
142 	return sprintf(buf, "0x%lx\n", port->start);
143 }
144 
145 static ssize_t portio_size_show(struct uio_port *port, char *buf)
146 {
147 	return sprintf(buf, "0x%lx\n", port->size);
148 }
149 
150 static 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 
160 struct 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 
166 static struct portio_sysfs_entry portio_name_attribute =
167 	__ATTR(name, S_IRUGO, portio_name_show, NULL);
168 static struct portio_sysfs_entry portio_start_attribute =
169 	__ATTR(start, S_IRUGO, portio_start_show, NULL);
170 static struct portio_sysfs_entry portio_size_attribute =
171 	__ATTR(size, S_IRUGO, portio_size_show, NULL);
172 static struct portio_sysfs_entry portio_porttype_attribute =
173 	__ATTR(porttype, S_IRUGO, portio_porttype_show, NULL);
174 
175 static 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 
183 static void portio_release(struct kobject *kobj)
184 {
185 	struct uio_portio *portio = to_portio(kobj);
186 	kfree(portio);
187 }
188 
189 static 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 
204 static const struct sysfs_ops portio_sysfs_ops = {
205 	.show = portio_type_show,
206 };
207 
208 static struct kobj_type portio_attr_type = {
209 	.release	= portio_release,
210 	.sysfs_ops	= &portio_sysfs_ops,
211 	.default_attrs	= portio_attrs,
212 };
213 
214 static 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 }
220 static DEVICE_ATTR_RO(name);
221 
222 static 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 }
228 static DEVICE_ATTR_RO(version);
229 
230 static 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 }
236 static DEVICE_ATTR_RO(event);
237 
238 static struct attribute *uio_attrs[] = {
239 	&dev_attr_name.attr,
240 	&dev_attr_version.attr,
241 	&dev_attr_event.attr,
242 	NULL,
243 };
244 ATTRIBUTE_GROUPS(uio);
245 
246 /* UIO class infrastructure */
247 static struct class uio_class = {
248 	.name = "uio",
249 	.dev_groups = uio_groups,
250 };
251 
252 /*
253  * device functions
254  */
255 static 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 				ret = -ENOMEM;
276 				goto err_map;
277 			}
278 		}
279 		map = kzalloc(sizeof(*map), GFP_KERNEL);
280 		if (!map) {
281 			ret = -ENOMEM;
282 			goto err_map_kobj;
283 		}
284 		kobject_init(&map->kobj, &map_attr_type);
285 		map->mem = mem;
286 		mem->map = map;
287 		ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
288 		if (ret)
289 			goto err_map_kobj;
290 		ret = kobject_uevent(&map->kobj, KOBJ_ADD);
291 		if (ret)
292 			goto err_map;
293 	}
294 
295 	for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
296 		port = &idev->info->port[pi];
297 		if (port->size == 0)
298 			break;
299 		if (!portio_found) {
300 			portio_found = 1;
301 			idev->portio_dir = kobject_create_and_add("portio",
302 							&idev->dev->kobj);
303 			if (!idev->portio_dir) {
304 				ret = -ENOMEM;
305 				goto err_portio;
306 			}
307 		}
308 		portio = kzalloc(sizeof(*portio), GFP_KERNEL);
309 		if (!portio) {
310 			ret = -ENOMEM;
311 			goto err_portio_kobj;
312 		}
313 		kobject_init(&portio->kobj, &portio_attr_type);
314 		portio->port = port;
315 		port->portio = portio;
316 		ret = kobject_add(&portio->kobj, idev->portio_dir,
317 							"port%d", pi);
318 		if (ret)
319 			goto err_portio_kobj;
320 		ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
321 		if (ret)
322 			goto err_portio;
323 	}
324 
325 	return 0;
326 
327 err_portio:
328 	pi--;
329 err_portio_kobj:
330 	for (; pi >= 0; pi--) {
331 		port = &idev->info->port[pi];
332 		portio = port->portio;
333 		kobject_put(&portio->kobj);
334 	}
335 	kobject_put(idev->portio_dir);
336 err_map:
337 	mi--;
338 err_map_kobj:
339 	for (; mi >= 0; mi--) {
340 		mem = &idev->info->mem[mi];
341 		map = mem->map;
342 		kobject_put(&map->kobj);
343 	}
344 	kobject_put(idev->map_dir);
345 	dev_err(idev->dev, "error creating sysfs files (%d)\n", ret);
346 	return ret;
347 }
348 
349 static void uio_dev_del_attributes(struct uio_device *idev)
350 {
351 	int i;
352 	struct uio_mem *mem;
353 	struct uio_port *port;
354 
355 	for (i = 0; i < MAX_UIO_MAPS; i++) {
356 		mem = &idev->info->mem[i];
357 		if (mem->size == 0)
358 			break;
359 		kobject_put(&mem->map->kobj);
360 	}
361 	kobject_put(idev->map_dir);
362 
363 	for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
364 		port = &idev->info->port[i];
365 		if (port->size == 0)
366 			break;
367 		kobject_put(&port->portio->kobj);
368 	}
369 	kobject_put(idev->portio_dir);
370 }
371 
372 static int uio_get_minor(struct uio_device *idev)
373 {
374 	int retval = -ENOMEM;
375 
376 	mutex_lock(&minor_lock);
377 	retval = idr_alloc(&uio_idr, idev, 0, UIO_MAX_DEVICES, GFP_KERNEL);
378 	if (retval >= 0) {
379 		idev->minor = retval;
380 		retval = 0;
381 	} else if (retval == -ENOSPC) {
382 		dev_err(idev->dev, "too many uio devices\n");
383 		retval = -EINVAL;
384 	}
385 	mutex_unlock(&minor_lock);
386 	return retval;
387 }
388 
389 static void uio_free_minor(struct uio_device *idev)
390 {
391 	mutex_lock(&minor_lock);
392 	idr_remove(&uio_idr, idev->minor);
393 	mutex_unlock(&minor_lock);
394 }
395 
396 /**
397  * uio_event_notify - trigger an interrupt event
398  * @info: UIO device capabilities
399  */
400 void uio_event_notify(struct uio_info *info)
401 {
402 	struct uio_device *idev = info->uio_dev;
403 
404 	atomic_inc(&idev->event);
405 	wake_up_interruptible(&idev->wait);
406 	kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
407 }
408 EXPORT_SYMBOL_GPL(uio_event_notify);
409 
410 /**
411  * uio_interrupt - hardware interrupt handler
412  * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
413  * @dev_id: Pointer to the devices uio_device structure
414  */
415 static irqreturn_t uio_interrupt(int irq, void *dev_id)
416 {
417 	struct uio_device *idev = (struct uio_device *)dev_id;
418 	irqreturn_t ret = idev->info->handler(irq, idev->info);
419 
420 	if (ret == IRQ_HANDLED)
421 		uio_event_notify(idev->info);
422 
423 	return ret;
424 }
425 
426 struct uio_listener {
427 	struct uio_device *dev;
428 	s32 event_count;
429 };
430 
431 static int uio_open(struct inode *inode, struct file *filep)
432 {
433 	struct uio_device *idev;
434 	struct uio_listener *listener;
435 	int ret = 0;
436 
437 	mutex_lock(&minor_lock);
438 	idev = idr_find(&uio_idr, iminor(inode));
439 	mutex_unlock(&minor_lock);
440 	if (!idev) {
441 		ret = -ENODEV;
442 		goto out;
443 	}
444 
445 	if (!try_module_get(idev->owner)) {
446 		ret = -ENODEV;
447 		goto out;
448 	}
449 
450 	listener = kmalloc(sizeof(*listener), GFP_KERNEL);
451 	if (!listener) {
452 		ret = -ENOMEM;
453 		goto err_alloc_listener;
454 	}
455 
456 	listener->dev = idev;
457 	listener->event_count = atomic_read(&idev->event);
458 	filep->private_data = listener;
459 
460 	if (idev->info->open) {
461 		ret = idev->info->open(idev->info, inode);
462 		if (ret)
463 			goto err_infoopen;
464 	}
465 	return 0;
466 
467 err_infoopen:
468 	kfree(listener);
469 
470 err_alloc_listener:
471 	module_put(idev->owner);
472 
473 out:
474 	return ret;
475 }
476 
477 static int uio_fasync(int fd, struct file *filep, int on)
478 {
479 	struct uio_listener *listener = filep->private_data;
480 	struct uio_device *idev = listener->dev;
481 
482 	return fasync_helper(fd, filep, on, &idev->async_queue);
483 }
484 
485 static int uio_release(struct inode *inode, struct file *filep)
486 {
487 	int ret = 0;
488 	struct uio_listener *listener = filep->private_data;
489 	struct uio_device *idev = listener->dev;
490 
491 	if (idev->info->release)
492 		ret = idev->info->release(idev->info, inode);
493 
494 	module_put(idev->owner);
495 	kfree(listener);
496 	return ret;
497 }
498 
499 static unsigned int uio_poll(struct file *filep, poll_table *wait)
500 {
501 	struct uio_listener *listener = filep->private_data;
502 	struct uio_device *idev = listener->dev;
503 
504 	if (!idev->info->irq)
505 		return -EIO;
506 
507 	poll_wait(filep, &idev->wait, wait);
508 	if (listener->event_count != atomic_read(&idev->event))
509 		return POLLIN | POLLRDNORM;
510 	return 0;
511 }
512 
513 static ssize_t uio_read(struct file *filep, char __user *buf,
514 			size_t count, loff_t *ppos)
515 {
516 	struct uio_listener *listener = filep->private_data;
517 	struct uio_device *idev = listener->dev;
518 	DECLARE_WAITQUEUE(wait, current);
519 	ssize_t retval;
520 	s32 event_count;
521 
522 	if (!idev->info->irq)
523 		return -EIO;
524 
525 	if (count != sizeof(s32))
526 		return -EINVAL;
527 
528 	add_wait_queue(&idev->wait, &wait);
529 
530 	do {
531 		set_current_state(TASK_INTERRUPTIBLE);
532 
533 		event_count = atomic_read(&idev->event);
534 		if (event_count != listener->event_count) {
535 			__set_current_state(TASK_RUNNING);
536 			if (copy_to_user(buf, &event_count, count))
537 				retval = -EFAULT;
538 			else {
539 				listener->event_count = event_count;
540 				retval = count;
541 			}
542 			break;
543 		}
544 
545 		if (filep->f_flags & O_NONBLOCK) {
546 			retval = -EAGAIN;
547 			break;
548 		}
549 
550 		if (signal_pending(current)) {
551 			retval = -ERESTARTSYS;
552 			break;
553 		}
554 		schedule();
555 	} while (1);
556 
557 	__set_current_state(TASK_RUNNING);
558 	remove_wait_queue(&idev->wait, &wait);
559 
560 	return retval;
561 }
562 
563 static ssize_t uio_write(struct file *filep, const char __user *buf,
564 			size_t count, loff_t *ppos)
565 {
566 	struct uio_listener *listener = filep->private_data;
567 	struct uio_device *idev = listener->dev;
568 	ssize_t retval;
569 	s32 irq_on;
570 
571 	if (!idev->info->irq)
572 		return -EIO;
573 
574 	if (count != sizeof(s32))
575 		return -EINVAL;
576 
577 	if (!idev->info->irqcontrol)
578 		return -ENOSYS;
579 
580 	if (copy_from_user(&irq_on, buf, count))
581 		return -EFAULT;
582 
583 	retval = idev->info->irqcontrol(idev->info, irq_on);
584 
585 	return retval ? retval : sizeof(s32);
586 }
587 
588 static int uio_find_mem_index(struct vm_area_struct *vma)
589 {
590 	struct uio_device *idev = vma->vm_private_data;
591 
592 	if (vma->vm_pgoff < MAX_UIO_MAPS) {
593 		if (idev->info->mem[vma->vm_pgoff].size == 0)
594 			return -1;
595 		return (int)vma->vm_pgoff;
596 	}
597 	return -1;
598 }
599 
600 static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
601 {
602 	struct uio_device *idev = vma->vm_private_data;
603 	struct page *page;
604 	unsigned long offset;
605 	void *addr;
606 
607 	int mi = uio_find_mem_index(vma);
608 	if (mi < 0)
609 		return VM_FAULT_SIGBUS;
610 
611 	/*
612 	 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
613 	 * to use mem[N].
614 	 */
615 	offset = (vmf->pgoff - mi) << PAGE_SHIFT;
616 
617 	addr = (void *)(unsigned long)idev->info->mem[mi].addr + offset;
618 	if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
619 		page = virt_to_page(addr);
620 	else
621 		page = vmalloc_to_page(addr);
622 	get_page(page);
623 	vmf->page = page;
624 	return 0;
625 }
626 
627 static const struct vm_operations_struct uio_logical_vm_ops = {
628 	.fault = uio_vma_fault,
629 };
630 
631 static int uio_mmap_logical(struct vm_area_struct *vma)
632 {
633 	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
634 	vma->vm_ops = &uio_logical_vm_ops;
635 	return 0;
636 }
637 
638 static const struct vm_operations_struct uio_physical_vm_ops = {
639 #ifdef CONFIG_HAVE_IOREMAP_PROT
640 	.access = generic_access_phys,
641 #endif
642 };
643 
644 static int uio_mmap_physical(struct vm_area_struct *vma)
645 {
646 	struct uio_device *idev = vma->vm_private_data;
647 	int mi = uio_find_mem_index(vma);
648 	struct uio_mem *mem;
649 	if (mi < 0)
650 		return -EINVAL;
651 	mem = idev->info->mem + mi;
652 
653 	if (mem->addr & ~PAGE_MASK)
654 		return -ENODEV;
655 	if (vma->vm_end - vma->vm_start > mem->size)
656 		return -EINVAL;
657 
658 	vma->vm_ops = &uio_physical_vm_ops;
659 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
660 
661 	/*
662 	 * We cannot use the vm_iomap_memory() helper here,
663 	 * because vma->vm_pgoff is the map index we looked
664 	 * up above in uio_find_mem_index(), rather than an
665 	 * actual page offset into the mmap.
666 	 *
667 	 * So we just do the physical mmap without a page
668 	 * offset.
669 	 */
670 	return remap_pfn_range(vma,
671 			       vma->vm_start,
672 			       mem->addr >> PAGE_SHIFT,
673 			       vma->vm_end - vma->vm_start,
674 			       vma->vm_page_prot);
675 }
676 
677 static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
678 {
679 	struct uio_listener *listener = filep->private_data;
680 	struct uio_device *idev = listener->dev;
681 	int mi;
682 	unsigned long requested_pages, actual_pages;
683 	int ret = 0;
684 
685 	if (vma->vm_end < vma->vm_start)
686 		return -EINVAL;
687 
688 	vma->vm_private_data = idev;
689 
690 	mi = uio_find_mem_index(vma);
691 	if (mi < 0)
692 		return -EINVAL;
693 
694 	requested_pages = vma_pages(vma);
695 	actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
696 			+ idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
697 	if (requested_pages > actual_pages)
698 		return -EINVAL;
699 
700 	if (idev->info->mmap) {
701 		ret = idev->info->mmap(idev->info, vma);
702 		return ret;
703 	}
704 
705 	switch (idev->info->mem[mi].memtype) {
706 		case UIO_MEM_PHYS:
707 			return uio_mmap_physical(vma);
708 		case UIO_MEM_LOGICAL:
709 		case UIO_MEM_VIRTUAL:
710 			return uio_mmap_logical(vma);
711 		default:
712 			return -EINVAL;
713 	}
714 }
715 
716 static const struct file_operations uio_fops = {
717 	.owner		= THIS_MODULE,
718 	.open		= uio_open,
719 	.release	= uio_release,
720 	.read		= uio_read,
721 	.write		= uio_write,
722 	.mmap		= uio_mmap,
723 	.poll		= uio_poll,
724 	.fasync		= uio_fasync,
725 	.llseek		= noop_llseek,
726 };
727 
728 static int uio_major_init(void)
729 {
730 	static const char name[] = "uio";
731 	struct cdev *cdev = NULL;
732 	dev_t uio_dev = 0;
733 	int result;
734 
735 	result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name);
736 	if (result)
737 		goto out;
738 
739 	result = -ENOMEM;
740 	cdev = cdev_alloc();
741 	if (!cdev)
742 		goto out_unregister;
743 
744 	cdev->owner = THIS_MODULE;
745 	cdev->ops = &uio_fops;
746 	kobject_set_name(&cdev->kobj, "%s", name);
747 
748 	result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES);
749 	if (result)
750 		goto out_put;
751 
752 	uio_major = MAJOR(uio_dev);
753 	uio_cdev = cdev;
754 	return 0;
755 out_put:
756 	kobject_put(&cdev->kobj);
757 out_unregister:
758 	unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
759 out:
760 	return result;
761 }
762 
763 static void uio_major_cleanup(void)
764 {
765 	unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
766 	cdev_del(uio_cdev);
767 }
768 
769 static int init_uio_class(void)
770 {
771 	int ret;
772 
773 	/* This is the first time in here, set everything up properly */
774 	ret = uio_major_init();
775 	if (ret)
776 		goto exit;
777 
778 	ret = class_register(&uio_class);
779 	if (ret) {
780 		printk(KERN_ERR "class_register failed for uio\n");
781 		goto err_class_register;
782 	}
783 	return 0;
784 
785 err_class_register:
786 	uio_major_cleanup();
787 exit:
788 	return ret;
789 }
790 
791 static void release_uio_class(void)
792 {
793 	class_unregister(&uio_class);
794 	uio_major_cleanup();
795 }
796 
797 /**
798  * uio_register_device - register a new userspace IO device
799  * @owner:	module that creates the new device
800  * @parent:	parent device
801  * @info:	UIO device capabilities
802  *
803  * returns zero on success or a negative error code.
804  */
805 int __uio_register_device(struct module *owner,
806 			  struct device *parent,
807 			  struct uio_info *info)
808 {
809 	struct uio_device *idev;
810 	int ret = 0;
811 
812 	if (!parent || !info || !info->name || !info->version)
813 		return -EINVAL;
814 
815 	info->uio_dev = NULL;
816 
817 	idev = devm_kzalloc(parent, sizeof(*idev), GFP_KERNEL);
818 	if (!idev) {
819 		return -ENOMEM;
820 	}
821 
822 	idev->owner = owner;
823 	idev->info = info;
824 	init_waitqueue_head(&idev->wait);
825 	atomic_set(&idev->event, 0);
826 
827 	ret = uio_get_minor(idev);
828 	if (ret)
829 		return ret;
830 
831 	idev->dev = device_create(&uio_class, parent,
832 				  MKDEV(uio_major, idev->minor), idev,
833 				  "uio%d", idev->minor);
834 	if (IS_ERR(idev->dev)) {
835 		printk(KERN_ERR "UIO: device register failed\n");
836 		ret = PTR_ERR(idev->dev);
837 		goto err_device_create;
838 	}
839 
840 	ret = uio_dev_add_attributes(idev);
841 	if (ret)
842 		goto err_uio_dev_add_attributes;
843 
844 	info->uio_dev = idev;
845 
846 	if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) {
847 		/*
848 		 * Note that we deliberately don't use devm_request_irq
849 		 * here. The parent module can unregister the UIO device
850 		 * and call pci_disable_msi, which requires that this
851 		 * irq has been freed. However, the device may have open
852 		 * FDs at the time of unregister and therefore may not be
853 		 * freed until they are released.
854 		 */
855 		ret = request_irq(info->irq, uio_interrupt,
856 				  info->irq_flags, info->name, idev);
857 		if (ret)
858 			goto err_request_irq;
859 	}
860 
861 	return 0;
862 
863 err_request_irq:
864 	uio_dev_del_attributes(idev);
865 err_uio_dev_add_attributes:
866 	device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
867 err_device_create:
868 	uio_free_minor(idev);
869 	return ret;
870 }
871 EXPORT_SYMBOL_GPL(__uio_register_device);
872 
873 /**
874  * uio_unregister_device - unregister a industrial IO device
875  * @info:	UIO device capabilities
876  *
877  */
878 void uio_unregister_device(struct uio_info *info)
879 {
880 	struct uio_device *idev;
881 
882 	if (!info || !info->uio_dev)
883 		return;
884 
885 	idev = info->uio_dev;
886 
887 	uio_free_minor(idev);
888 
889 	uio_dev_del_attributes(idev);
890 
891 	if (info->irq && info->irq != UIO_IRQ_CUSTOM)
892 		free_irq(info->irq, idev);
893 
894 	device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
895 
896 	return;
897 }
898 EXPORT_SYMBOL_GPL(uio_unregister_device);
899 
900 static int __init uio_init(void)
901 {
902 	return init_uio_class();
903 }
904 
905 static void __exit uio_exit(void)
906 {
907 	release_uio_class();
908 	idr_destroy(&uio_idr);
909 }
910 
911 module_init(uio_init)
912 module_exit(uio_exit)
913 MODULE_LICENSE("GPL v2");
914