xref: /openbmc/linux/drivers/uio/uio.c (revision abe9af53) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * drivers/uio/uio.c
4  *
5  * Copyright(C) 2005, Benedikt Spranger <b.spranger@linutronix.de>
6  * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
7  * Copyright(C) 2006, Hans J. Koch <hjk@hansjkoch.de>
8  * Copyright(C) 2006, Greg Kroah-Hartman <greg@kroah.com>
9  *
10  * Userspace IO
11  *
12  * Base Functions
13  */
14 
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/poll.h>
18 #include <linux/device.h>
19 #include <linux/slab.h>
20 #include <linux/mm.h>
21 #include <linux/idr.h>
22 #include <linux/sched/signal.h>
23 #include <linux/string.h>
24 #include <linux/kobject.h>
25 #include <linux/cdev.h>
26 #include <linux/uio_driver.h>
27 
28 #define UIO_MAX_DEVICES		(1U << MINORBITS)
29 
30 static int uio_major;
31 static struct cdev *uio_cdev;
32 static DEFINE_IDR(uio_idr);
33 static const struct file_operations uio_fops;
34 
35 /* Protect idr accesses */
36 static DEFINE_MUTEX(minor_lock);
37 
38 /*
39  * attributes
40  */
41 
42 struct uio_map {
43 	struct kobject kobj;
44 	struct uio_mem *mem;
45 };
46 #define to_map(map) container_of(map, struct uio_map, kobj)
47 
48 static ssize_t map_name_show(struct uio_mem *mem, char *buf)
49 {
50 	if (unlikely(!mem->name))
51 		mem->name = "";
52 
53 	return sprintf(buf, "%s\n", mem->name);
54 }
55 
56 static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
57 {
58 	return sprintf(buf, "%pa\n", &mem->addr);
59 }
60 
61 static ssize_t map_size_show(struct uio_mem *mem, char *buf)
62 {
63 	return sprintf(buf, "%pa\n", &mem->size);
64 }
65 
66 static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
67 {
68 	return sprintf(buf, "0x%llx\n", (unsigned long long)mem->offs);
69 }
70 
71 struct map_sysfs_entry {
72 	struct attribute attr;
73 	ssize_t (*show)(struct uio_mem *, char *);
74 	ssize_t (*store)(struct uio_mem *, const char *, size_t);
75 };
76 
77 static struct map_sysfs_entry name_attribute =
78 	__ATTR(name, S_IRUGO, map_name_show, NULL);
79 static struct map_sysfs_entry addr_attribute =
80 	__ATTR(addr, S_IRUGO, map_addr_show, NULL);
81 static struct map_sysfs_entry size_attribute =
82 	__ATTR(size, S_IRUGO, map_size_show, NULL);
83 static struct map_sysfs_entry offset_attribute =
84 	__ATTR(offset, S_IRUGO, map_offset_show, NULL);
85 
86 static struct attribute *attrs[] = {
87 	&name_attribute.attr,
88 	&addr_attribute.attr,
89 	&size_attribute.attr,
90 	&offset_attribute.attr,
91 	NULL,	/* need to NULL terminate the list of attributes */
92 };
93 
94 static void map_release(struct kobject *kobj)
95 {
96 	struct uio_map *map = to_map(kobj);
97 	kfree(map);
98 }
99 
100 static ssize_t map_type_show(struct kobject *kobj, struct attribute *attr,
101 			     char *buf)
102 {
103 	struct uio_map *map = to_map(kobj);
104 	struct uio_mem *mem = map->mem;
105 	struct map_sysfs_entry *entry;
106 
107 	entry = container_of(attr, struct map_sysfs_entry, attr);
108 
109 	if (!entry->show)
110 		return -EIO;
111 
112 	return entry->show(mem, buf);
113 }
114 
115 static const struct sysfs_ops map_sysfs_ops = {
116 	.show = map_type_show,
117 };
118 
119 static struct kobj_type map_attr_type = {
120 	.release	= map_release,
121 	.sysfs_ops	= &map_sysfs_ops,
122 	.default_attrs	= attrs,
123 };
124 
125 struct uio_portio {
126 	struct kobject kobj;
127 	struct uio_port *port;
128 };
129 #define to_portio(portio) container_of(portio, struct uio_portio, kobj)
130 
131 static ssize_t portio_name_show(struct uio_port *port, char *buf)
132 {
133 	if (unlikely(!port->name))
134 		port->name = "";
135 
136 	return sprintf(buf, "%s\n", port->name);
137 }
138 
139 static ssize_t portio_start_show(struct uio_port *port, char *buf)
140 {
141 	return sprintf(buf, "0x%lx\n", port->start);
142 }
143 
144 static ssize_t portio_size_show(struct uio_port *port, char *buf)
145 {
146 	return sprintf(buf, "0x%lx\n", port->size);
147 }
148 
149 static ssize_t portio_porttype_show(struct uio_port *port, char *buf)
150 {
151 	const char *porttypes[] = {"none", "x86", "gpio", "other"};
152 
153 	if ((port->porttype < 0) || (port->porttype > UIO_PORT_OTHER))
154 		return -EINVAL;
155 
156 	return sprintf(buf, "port_%s\n", porttypes[port->porttype]);
157 }
158 
159 struct portio_sysfs_entry {
160 	struct attribute attr;
161 	ssize_t (*show)(struct uio_port *, char *);
162 	ssize_t (*store)(struct uio_port *, const char *, size_t);
163 };
164 
165 static struct portio_sysfs_entry portio_name_attribute =
166 	__ATTR(name, S_IRUGO, portio_name_show, NULL);
167 static struct portio_sysfs_entry portio_start_attribute =
168 	__ATTR(start, S_IRUGO, portio_start_show, NULL);
169 static struct portio_sysfs_entry portio_size_attribute =
170 	__ATTR(size, S_IRUGO, portio_size_show, NULL);
171 static struct portio_sysfs_entry portio_porttype_attribute =
172 	__ATTR(porttype, S_IRUGO, portio_porttype_show, NULL);
173 
174 static struct attribute *portio_attrs[] = {
175 	&portio_name_attribute.attr,
176 	&portio_start_attribute.attr,
177 	&portio_size_attribute.attr,
178 	&portio_porttype_attribute.attr,
179 	NULL,
180 };
181 
182 static void portio_release(struct kobject *kobj)
183 {
184 	struct uio_portio *portio = to_portio(kobj);
185 	kfree(portio);
186 }
187 
188 static ssize_t portio_type_show(struct kobject *kobj, struct attribute *attr,
189 			     char *buf)
190 {
191 	struct uio_portio *portio = to_portio(kobj);
192 	struct uio_port *port = portio->port;
193 	struct portio_sysfs_entry *entry;
194 
195 	entry = container_of(attr, struct portio_sysfs_entry, attr);
196 
197 	if (!entry->show)
198 		return -EIO;
199 
200 	return entry->show(port, buf);
201 }
202 
203 static const struct sysfs_ops portio_sysfs_ops = {
204 	.show = portio_type_show,
205 };
206 
207 static struct kobj_type portio_attr_type = {
208 	.release	= portio_release,
209 	.sysfs_ops	= &portio_sysfs_ops,
210 	.default_attrs	= portio_attrs,
211 };
212 
213 static ssize_t name_show(struct device *dev,
214 			 struct device_attribute *attr, char *buf)
215 {
216 	struct uio_device *idev = dev_get_drvdata(dev);
217 	int ret;
218 
219 	mutex_lock(&idev->info_lock);
220 	if (!idev->info) {
221 		ret = -EINVAL;
222 		dev_err(dev, "the device has been unregistered\n");
223 		goto out;
224 	}
225 
226 	ret = sprintf(buf, "%s\n", idev->info->name);
227 
228 out:
229 	mutex_unlock(&idev->info_lock);
230 	return ret;
231 }
232 static DEVICE_ATTR_RO(name);
233 
234 static ssize_t version_show(struct device *dev,
235 			    struct device_attribute *attr, char *buf)
236 {
237 	struct uio_device *idev = dev_get_drvdata(dev);
238 	int ret;
239 
240 	mutex_lock(&idev->info_lock);
241 	if (!idev->info) {
242 		ret = -EINVAL;
243 		dev_err(dev, "the device has been unregistered\n");
244 		goto out;
245 	}
246 
247 	ret = sprintf(buf, "%s\n", idev->info->version);
248 
249 out:
250 	mutex_unlock(&idev->info_lock);
251 	return ret;
252 }
253 static DEVICE_ATTR_RO(version);
254 
255 static ssize_t event_show(struct device *dev,
256 			  struct device_attribute *attr, char *buf)
257 {
258 	struct uio_device *idev = dev_get_drvdata(dev);
259 	return sprintf(buf, "%u\n", (unsigned int)atomic_read(&idev->event));
260 }
261 static DEVICE_ATTR_RO(event);
262 
263 static struct attribute *uio_attrs[] = {
264 	&dev_attr_name.attr,
265 	&dev_attr_version.attr,
266 	&dev_attr_event.attr,
267 	NULL,
268 };
269 ATTRIBUTE_GROUPS(uio);
270 
271 /* UIO class infrastructure */
272 static struct class uio_class = {
273 	.name = "uio",
274 	.dev_groups = uio_groups,
275 };
276 
277 static bool uio_class_registered;
278 
279 /*
280  * device functions
281  */
282 static int uio_dev_add_attributes(struct uio_device *idev)
283 {
284 	int ret;
285 	int mi, pi;
286 	int map_found = 0;
287 	int portio_found = 0;
288 	struct uio_mem *mem;
289 	struct uio_map *map;
290 	struct uio_port *port;
291 	struct uio_portio *portio;
292 
293 	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
294 		mem = &idev->info->mem[mi];
295 		if (mem->size == 0)
296 			break;
297 		if (!map_found) {
298 			map_found = 1;
299 			idev->map_dir = kobject_create_and_add("maps",
300 							&idev->dev.kobj);
301 			if (!idev->map_dir) {
302 				ret = -ENOMEM;
303 				goto err_map;
304 			}
305 		}
306 		map = kzalloc(sizeof(*map), GFP_KERNEL);
307 		if (!map) {
308 			ret = -ENOMEM;
309 			goto err_map;
310 		}
311 		kobject_init(&map->kobj, &map_attr_type);
312 		map->mem = mem;
313 		mem->map = map;
314 		ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
315 		if (ret)
316 			goto err_map_kobj;
317 		ret = kobject_uevent(&map->kobj, KOBJ_ADD);
318 		if (ret)
319 			goto err_map_kobj;
320 	}
321 
322 	for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
323 		port = &idev->info->port[pi];
324 		if (port->size == 0)
325 			break;
326 		if (!portio_found) {
327 			portio_found = 1;
328 			idev->portio_dir = kobject_create_and_add("portio",
329 							&idev->dev.kobj);
330 			if (!idev->portio_dir) {
331 				ret = -ENOMEM;
332 				goto err_portio;
333 			}
334 		}
335 		portio = kzalloc(sizeof(*portio), GFP_KERNEL);
336 		if (!portio) {
337 			ret = -ENOMEM;
338 			goto err_portio;
339 		}
340 		kobject_init(&portio->kobj, &portio_attr_type);
341 		portio->port = port;
342 		port->portio = portio;
343 		ret = kobject_add(&portio->kobj, idev->portio_dir,
344 							"port%d", pi);
345 		if (ret)
346 			goto err_portio_kobj;
347 		ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
348 		if (ret)
349 			goto err_portio_kobj;
350 	}
351 
352 	return 0;
353 
354 err_portio:
355 	pi--;
356 err_portio_kobj:
357 	for (; pi >= 0; pi--) {
358 		port = &idev->info->port[pi];
359 		portio = port->portio;
360 		kobject_put(&portio->kobj);
361 	}
362 	kobject_put(idev->portio_dir);
363 err_map:
364 	mi--;
365 err_map_kobj:
366 	for (; mi >= 0; mi--) {
367 		mem = &idev->info->mem[mi];
368 		map = mem->map;
369 		kobject_put(&map->kobj);
370 	}
371 	kobject_put(idev->map_dir);
372 	dev_err(&idev->dev, "error creating sysfs files (%d)\n", ret);
373 	return ret;
374 }
375 
376 static void uio_dev_del_attributes(struct uio_device *idev)
377 {
378 	int i;
379 	struct uio_mem *mem;
380 	struct uio_port *port;
381 
382 	for (i = 0; i < MAX_UIO_MAPS; i++) {
383 		mem = &idev->info->mem[i];
384 		if (mem->size == 0)
385 			break;
386 		kobject_put(&mem->map->kobj);
387 	}
388 	kobject_put(idev->map_dir);
389 
390 	for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
391 		port = &idev->info->port[i];
392 		if (port->size == 0)
393 			break;
394 		kobject_put(&port->portio->kobj);
395 	}
396 	kobject_put(idev->portio_dir);
397 }
398 
399 static int uio_get_minor(struct uio_device *idev)
400 {
401 	int retval;
402 
403 	mutex_lock(&minor_lock);
404 	retval = idr_alloc(&uio_idr, idev, 0, UIO_MAX_DEVICES, GFP_KERNEL);
405 	if (retval >= 0) {
406 		idev->minor = retval;
407 		retval = 0;
408 	} else if (retval == -ENOSPC) {
409 		dev_err(&idev->dev, "too many uio devices\n");
410 		retval = -EINVAL;
411 	}
412 	mutex_unlock(&minor_lock);
413 	return retval;
414 }
415 
416 static void uio_free_minor(unsigned long minor)
417 {
418 	mutex_lock(&minor_lock);
419 	idr_remove(&uio_idr, minor);
420 	mutex_unlock(&minor_lock);
421 }
422 
423 /**
424  * uio_event_notify - trigger an interrupt event
425  * @info: UIO device capabilities
426  */
427 void uio_event_notify(struct uio_info *info)
428 {
429 	struct uio_device *idev = info->uio_dev;
430 
431 	atomic_inc(&idev->event);
432 	wake_up_interruptible(&idev->wait);
433 	kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
434 }
435 EXPORT_SYMBOL_GPL(uio_event_notify);
436 
437 /**
438  * uio_interrupt - hardware interrupt handler
439  * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
440  * @dev_id: Pointer to the devices uio_device structure
441  */
442 static irqreturn_t uio_interrupt(int irq, void *dev_id)
443 {
444 	struct uio_device *idev = (struct uio_device *)dev_id;
445 	irqreturn_t ret;
446 
447 	ret = idev->info->handler(irq, idev->info);
448 	if (ret == IRQ_HANDLED)
449 		uio_event_notify(idev->info);
450 
451 	return ret;
452 }
453 
454 struct uio_listener {
455 	struct uio_device *dev;
456 	s32 event_count;
457 };
458 
459 static int uio_open(struct inode *inode, struct file *filep)
460 {
461 	struct uio_device *idev;
462 	struct uio_listener *listener;
463 	int ret = 0;
464 
465 	mutex_lock(&minor_lock);
466 	idev = idr_find(&uio_idr, iminor(inode));
467 	mutex_unlock(&minor_lock);
468 	if (!idev) {
469 		ret = -ENODEV;
470 		goto out;
471 	}
472 
473 	get_device(&idev->dev);
474 
475 	if (!try_module_get(idev->owner)) {
476 		ret = -ENODEV;
477 		goto err_module_get;
478 	}
479 
480 	listener = kmalloc(sizeof(*listener), GFP_KERNEL);
481 	if (!listener) {
482 		ret = -ENOMEM;
483 		goto err_alloc_listener;
484 	}
485 
486 	listener->dev = idev;
487 	listener->event_count = atomic_read(&idev->event);
488 	filep->private_data = listener;
489 
490 	mutex_lock(&idev->info_lock);
491 	if (!idev->info) {
492 		mutex_unlock(&idev->info_lock);
493 		ret = -EINVAL;
494 		goto err_infoopen;
495 	}
496 
497 	if (idev->info->open)
498 		ret = idev->info->open(idev->info, inode);
499 	mutex_unlock(&idev->info_lock);
500 	if (ret)
501 		goto err_infoopen;
502 
503 	return 0;
504 
505 err_infoopen:
506 	kfree(listener);
507 
508 err_alloc_listener:
509 	module_put(idev->owner);
510 
511 err_module_get:
512 	put_device(&idev->dev);
513 
514 out:
515 	return ret;
516 }
517 
518 static int uio_fasync(int fd, struct file *filep, int on)
519 {
520 	struct uio_listener *listener = filep->private_data;
521 	struct uio_device *idev = listener->dev;
522 
523 	return fasync_helper(fd, filep, on, &idev->async_queue);
524 }
525 
526 static int uio_release(struct inode *inode, struct file *filep)
527 {
528 	int ret = 0;
529 	struct uio_listener *listener = filep->private_data;
530 	struct uio_device *idev = listener->dev;
531 
532 	mutex_lock(&idev->info_lock);
533 	if (idev->info && idev->info->release)
534 		ret = idev->info->release(idev->info, inode);
535 	mutex_unlock(&idev->info_lock);
536 
537 	module_put(idev->owner);
538 	kfree(listener);
539 	put_device(&idev->dev);
540 	return ret;
541 }
542 
543 static __poll_t uio_poll(struct file *filep, poll_table *wait)
544 {
545 	struct uio_listener *listener = filep->private_data;
546 	struct uio_device *idev = listener->dev;
547 	__poll_t ret = 0;
548 
549 	mutex_lock(&idev->info_lock);
550 	if (!idev->info || !idev->info->irq)
551 		ret = -EIO;
552 	mutex_unlock(&idev->info_lock);
553 
554 	if (ret)
555 		return ret;
556 
557 	poll_wait(filep, &idev->wait, wait);
558 	if (listener->event_count != atomic_read(&idev->event))
559 		return EPOLLIN | EPOLLRDNORM;
560 	return 0;
561 }
562 
563 static ssize_t uio_read(struct file *filep, 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 	DECLARE_WAITQUEUE(wait, current);
569 	ssize_t retval = 0;
570 	s32 event_count;
571 
572 	if (count != sizeof(s32))
573 		return -EINVAL;
574 
575 	add_wait_queue(&idev->wait, &wait);
576 
577 	do {
578 		mutex_lock(&idev->info_lock);
579 		if (!idev->info || !idev->info->irq) {
580 			retval = -EIO;
581 			mutex_unlock(&idev->info_lock);
582 			break;
583 		}
584 		mutex_unlock(&idev->info_lock);
585 
586 		set_current_state(TASK_INTERRUPTIBLE);
587 
588 		event_count = atomic_read(&idev->event);
589 		if (event_count != listener->event_count) {
590 			__set_current_state(TASK_RUNNING);
591 			if (copy_to_user(buf, &event_count, count))
592 				retval = -EFAULT;
593 			else {
594 				listener->event_count = event_count;
595 				retval = count;
596 			}
597 			break;
598 		}
599 
600 		if (filep->f_flags & O_NONBLOCK) {
601 			retval = -EAGAIN;
602 			break;
603 		}
604 
605 		if (signal_pending(current)) {
606 			retval = -ERESTARTSYS;
607 			break;
608 		}
609 		schedule();
610 	} while (1);
611 
612 	__set_current_state(TASK_RUNNING);
613 	remove_wait_queue(&idev->wait, &wait);
614 
615 	return retval;
616 }
617 
618 static ssize_t uio_write(struct file *filep, const char __user *buf,
619 			size_t count, loff_t *ppos)
620 {
621 	struct uio_listener *listener = filep->private_data;
622 	struct uio_device *idev = listener->dev;
623 	ssize_t retval;
624 	s32 irq_on;
625 
626 	if (count != sizeof(s32))
627 		return -EINVAL;
628 
629 	if (copy_from_user(&irq_on, buf, count))
630 		return -EFAULT;
631 
632 	mutex_lock(&idev->info_lock);
633 	if (!idev->info) {
634 		retval = -EINVAL;
635 		goto out;
636 	}
637 
638 	if (!idev->info->irq) {
639 		retval = -EIO;
640 		goto out;
641 	}
642 
643 	if (!idev->info->irqcontrol) {
644 		retval = -ENOSYS;
645 		goto out;
646 	}
647 
648 	retval = idev->info->irqcontrol(idev->info, irq_on);
649 
650 out:
651 	mutex_unlock(&idev->info_lock);
652 	return retval ? retval : sizeof(s32);
653 }
654 
655 static int uio_find_mem_index(struct vm_area_struct *vma)
656 {
657 	struct uio_device *idev = vma->vm_private_data;
658 
659 	if (vma->vm_pgoff < MAX_UIO_MAPS) {
660 		if (idev->info->mem[vma->vm_pgoff].size == 0)
661 			return -1;
662 		return (int)vma->vm_pgoff;
663 	}
664 	return -1;
665 }
666 
667 static vm_fault_t uio_vma_fault(struct vm_fault *vmf)
668 {
669 	struct uio_device *idev = vmf->vma->vm_private_data;
670 	struct page *page;
671 	unsigned long offset;
672 	void *addr;
673 	vm_fault_t ret = 0;
674 	int mi;
675 
676 	mutex_lock(&idev->info_lock);
677 	if (!idev->info) {
678 		ret = VM_FAULT_SIGBUS;
679 		goto out;
680 	}
681 
682 	mi = uio_find_mem_index(vmf->vma);
683 	if (mi < 0) {
684 		ret = VM_FAULT_SIGBUS;
685 		goto out;
686 	}
687 
688 	/*
689 	 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
690 	 * to use mem[N].
691 	 */
692 	offset = (vmf->pgoff - mi) << PAGE_SHIFT;
693 
694 	addr = (void *)(unsigned long)idev->info->mem[mi].addr + offset;
695 	if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
696 		page = virt_to_page(addr);
697 	else
698 		page = vmalloc_to_page(addr);
699 	get_page(page);
700 	vmf->page = page;
701 
702 out:
703 	mutex_unlock(&idev->info_lock);
704 
705 	return ret;
706 }
707 
708 static const struct vm_operations_struct uio_logical_vm_ops = {
709 	.fault = uio_vma_fault,
710 };
711 
712 static int uio_mmap_logical(struct vm_area_struct *vma)
713 {
714 	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
715 	vma->vm_ops = &uio_logical_vm_ops;
716 	return 0;
717 }
718 
719 static const struct vm_operations_struct uio_physical_vm_ops = {
720 #ifdef CONFIG_HAVE_IOREMAP_PROT
721 	.access = generic_access_phys,
722 #endif
723 };
724 
725 static int uio_mmap_physical(struct vm_area_struct *vma)
726 {
727 	struct uio_device *idev = vma->vm_private_data;
728 	int mi = uio_find_mem_index(vma);
729 	struct uio_mem *mem;
730 
731 	if (mi < 0)
732 		return -EINVAL;
733 	mem = idev->info->mem + mi;
734 
735 	if (mem->addr & ~PAGE_MASK)
736 		return -ENODEV;
737 	if (vma->vm_end - vma->vm_start > mem->size)
738 		return -EINVAL;
739 
740 	vma->vm_ops = &uio_physical_vm_ops;
741 	if (idev->info->mem[mi].memtype == UIO_MEM_PHYS)
742 		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
743 
744 	/*
745 	 * We cannot use the vm_iomap_memory() helper here,
746 	 * because vma->vm_pgoff is the map index we looked
747 	 * up above in uio_find_mem_index(), rather than an
748 	 * actual page offset into the mmap.
749 	 *
750 	 * So we just do the physical mmap without a page
751 	 * offset.
752 	 */
753 	return remap_pfn_range(vma,
754 			       vma->vm_start,
755 			       mem->addr >> PAGE_SHIFT,
756 			       vma->vm_end - vma->vm_start,
757 			       vma->vm_page_prot);
758 }
759 
760 static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
761 {
762 	struct uio_listener *listener = filep->private_data;
763 	struct uio_device *idev = listener->dev;
764 	int mi;
765 	unsigned long requested_pages, actual_pages;
766 	int ret = 0;
767 
768 	if (vma->vm_end < vma->vm_start)
769 		return -EINVAL;
770 
771 	vma->vm_private_data = idev;
772 
773 	mutex_lock(&idev->info_lock);
774 	if (!idev->info) {
775 		ret = -EINVAL;
776 		goto out;
777 	}
778 
779 	mi = uio_find_mem_index(vma);
780 	if (mi < 0) {
781 		ret = -EINVAL;
782 		goto out;
783 	}
784 
785 	requested_pages = vma_pages(vma);
786 	actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
787 			+ idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
788 	if (requested_pages > actual_pages) {
789 		ret = -EINVAL;
790 		goto out;
791 	}
792 
793 	if (idev->info->mmap) {
794 		ret = idev->info->mmap(idev->info, vma);
795 		goto out;
796 	}
797 
798 	switch (idev->info->mem[mi].memtype) {
799 	case UIO_MEM_IOVA:
800 	case UIO_MEM_PHYS:
801 		ret = uio_mmap_physical(vma);
802 		break;
803 	case UIO_MEM_LOGICAL:
804 	case UIO_MEM_VIRTUAL:
805 		ret = uio_mmap_logical(vma);
806 		break;
807 	default:
808 		ret = -EINVAL;
809 	}
810 
811  out:
812 	mutex_unlock(&idev->info_lock);
813 	return ret;
814 }
815 
816 static const struct file_operations uio_fops = {
817 	.owner		= THIS_MODULE,
818 	.open		= uio_open,
819 	.release	= uio_release,
820 	.read		= uio_read,
821 	.write		= uio_write,
822 	.mmap		= uio_mmap,
823 	.poll		= uio_poll,
824 	.fasync		= uio_fasync,
825 	.llseek		= noop_llseek,
826 };
827 
828 static int uio_major_init(void)
829 {
830 	static const char name[] = "uio";
831 	struct cdev *cdev = NULL;
832 	dev_t uio_dev = 0;
833 	int result;
834 
835 	result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name);
836 	if (result)
837 		goto out;
838 
839 	result = -ENOMEM;
840 	cdev = cdev_alloc();
841 	if (!cdev)
842 		goto out_unregister;
843 
844 	cdev->owner = THIS_MODULE;
845 	cdev->ops = &uio_fops;
846 	kobject_set_name(&cdev->kobj, "%s", name);
847 
848 	result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES);
849 	if (result)
850 		goto out_put;
851 
852 	uio_major = MAJOR(uio_dev);
853 	uio_cdev = cdev;
854 	return 0;
855 out_put:
856 	kobject_put(&cdev->kobj);
857 out_unregister:
858 	unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
859 out:
860 	return result;
861 }
862 
863 static void uio_major_cleanup(void)
864 {
865 	unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
866 	cdev_del(uio_cdev);
867 }
868 
869 static int init_uio_class(void)
870 {
871 	int ret;
872 
873 	/* This is the first time in here, set everything up properly */
874 	ret = uio_major_init();
875 	if (ret)
876 		goto exit;
877 
878 	ret = class_register(&uio_class);
879 	if (ret) {
880 		printk(KERN_ERR "class_register failed for uio\n");
881 		goto err_class_register;
882 	}
883 
884 	uio_class_registered = true;
885 
886 	return 0;
887 
888 err_class_register:
889 	uio_major_cleanup();
890 exit:
891 	return ret;
892 }
893 
894 static void release_uio_class(void)
895 {
896 	uio_class_registered = false;
897 	class_unregister(&uio_class);
898 	uio_major_cleanup();
899 }
900 
901 static void uio_device_release(struct device *dev)
902 {
903 	struct uio_device *idev = dev_get_drvdata(dev);
904 
905 	kfree(idev);
906 }
907 
908 /**
909  * __uio_register_device - register a new userspace IO device
910  * @owner:	module that creates the new device
911  * @parent:	parent device
912  * @info:	UIO device capabilities
913  *
914  * returns zero on success or a negative error code.
915  */
916 int __uio_register_device(struct module *owner,
917 			  struct device *parent,
918 			  struct uio_info *info)
919 {
920 	struct uio_device *idev;
921 	int ret = 0;
922 
923 	if (!uio_class_registered)
924 		return -EPROBE_DEFER;
925 
926 	if (!parent || !info || !info->name || !info->version)
927 		return -EINVAL;
928 
929 	info->uio_dev = NULL;
930 
931 	idev = kzalloc(sizeof(*idev), GFP_KERNEL);
932 	if (!idev) {
933 		return -ENOMEM;
934 	}
935 
936 	idev->owner = owner;
937 	idev->info = info;
938 	mutex_init(&idev->info_lock);
939 	init_waitqueue_head(&idev->wait);
940 	atomic_set(&idev->event, 0);
941 
942 	ret = uio_get_minor(idev);
943 	if (ret) {
944 		kfree(idev);
945 		return ret;
946 	}
947 
948 	device_initialize(&idev->dev);
949 	idev->dev.devt = MKDEV(uio_major, idev->minor);
950 	idev->dev.class = &uio_class;
951 	idev->dev.parent = parent;
952 	idev->dev.release = uio_device_release;
953 	dev_set_drvdata(&idev->dev, idev);
954 
955 	ret = dev_set_name(&idev->dev, "uio%d", idev->minor);
956 	if (ret)
957 		goto err_device_create;
958 
959 	ret = device_add(&idev->dev);
960 	if (ret)
961 		goto err_device_create;
962 
963 	ret = uio_dev_add_attributes(idev);
964 	if (ret)
965 		goto err_uio_dev_add_attributes;
966 
967 	info->uio_dev = idev;
968 
969 	if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) {
970 		/*
971 		 * Note that we deliberately don't use devm_request_irq
972 		 * here. The parent module can unregister the UIO device
973 		 * and call pci_disable_msi, which requires that this
974 		 * irq has been freed. However, the device may have open
975 		 * FDs at the time of unregister and therefore may not be
976 		 * freed until they are released.
977 		 */
978 		ret = request_irq(info->irq, uio_interrupt,
979 				  info->irq_flags, info->name, idev);
980 		if (ret) {
981 			info->uio_dev = NULL;
982 			goto err_request_irq;
983 		}
984 	}
985 
986 	return 0;
987 
988 err_request_irq:
989 	uio_dev_del_attributes(idev);
990 err_uio_dev_add_attributes:
991 	device_del(&idev->dev);
992 err_device_create:
993 	uio_free_minor(idev->minor);
994 	put_device(&idev->dev);
995 	return ret;
996 }
997 EXPORT_SYMBOL_GPL(__uio_register_device);
998 
999 static void devm_uio_unregister_device(struct device *dev, void *res)
1000 {
1001 	uio_unregister_device(*(struct uio_info **)res);
1002 }
1003 
1004 /**
1005  * __devm_uio_register_device - Resource managed uio_register_device()
1006  * @owner:	module that creates the new device
1007  * @parent:	parent device
1008  * @info:	UIO device capabilities
1009  *
1010  * returns zero on success or a negative error code.
1011  */
1012 int __devm_uio_register_device(struct module *owner,
1013 			       struct device *parent,
1014 			       struct uio_info *info)
1015 {
1016 	struct uio_info **ptr;
1017 	int ret;
1018 
1019 	ptr = devres_alloc(devm_uio_unregister_device, sizeof(*ptr),
1020 			   GFP_KERNEL);
1021 	if (!ptr)
1022 		return -ENOMEM;
1023 
1024 	*ptr = info;
1025 	ret = __uio_register_device(owner, parent, info);
1026 	if (ret) {
1027 		devres_free(ptr);
1028 		return ret;
1029 	}
1030 
1031 	devres_add(parent, ptr);
1032 
1033 	return 0;
1034 }
1035 EXPORT_SYMBOL_GPL(__devm_uio_register_device);
1036 
1037 /**
1038  * uio_unregister_device - unregister a industrial IO device
1039  * @info:	UIO device capabilities
1040  *
1041  */
1042 void uio_unregister_device(struct uio_info *info)
1043 {
1044 	struct uio_device *idev;
1045 	unsigned long minor;
1046 
1047 	if (!info || !info->uio_dev)
1048 		return;
1049 
1050 	idev = info->uio_dev;
1051 	minor = idev->minor;
1052 
1053 	mutex_lock(&idev->info_lock);
1054 	uio_dev_del_attributes(idev);
1055 
1056 	if (info->irq && info->irq != UIO_IRQ_CUSTOM)
1057 		free_irq(info->irq, idev);
1058 
1059 	idev->info = NULL;
1060 	mutex_unlock(&idev->info_lock);
1061 
1062 	wake_up_interruptible(&idev->wait);
1063 	kill_fasync(&idev->async_queue, SIGIO, POLL_HUP);
1064 
1065 	device_unregister(&idev->dev);
1066 
1067 	uio_free_minor(minor);
1068 
1069 	return;
1070 }
1071 EXPORT_SYMBOL_GPL(uio_unregister_device);
1072 
1073 static int __init uio_init(void)
1074 {
1075 	return init_uio_class();
1076 }
1077 
1078 static void __exit uio_exit(void)
1079 {
1080 	release_uio_class();
1081 	idr_destroy(&uio_idr);
1082 }
1083 
1084 module_init(uio_init)
1085 module_exit(uio_exit)
1086 MODULE_LICENSE("GPL v2");
1087