xref: /kernel/linux/linux-5.10/drivers/uio/uio.c (revision 8c2ecf20) 
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
30static int uio_major;
31static struct cdev *uio_cdev;
32static DEFINE_IDR(uio_idr);
33static const struct file_operations uio_fops;
34
35/* Protect idr accesses */
36static DEFINE_MUTEX(minor_lock);
37
38/*
39 * attributes
40 */
41
42struct 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
48static 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
56static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
57{
58	return sprintf(buf, "%pa\n", &mem->addr);
59}
60
61static ssize_t map_size_show(struct uio_mem *mem, char *buf)
62{
63	return sprintf(buf, "%pa\n", &mem->size);
64}
65
66static 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
71struct 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
77static struct map_sysfs_entry name_attribute =
78	__ATTR(name, S_IRUGO, map_name_show, NULL);
79static struct map_sysfs_entry addr_attribute =
80	__ATTR(addr, S_IRUGO, map_addr_show, NULL);
81static struct map_sysfs_entry size_attribute =
82	__ATTR(size, S_IRUGO, map_size_show, NULL);
83static struct map_sysfs_entry offset_attribute =
84	__ATTR(offset, S_IRUGO, map_offset_show, NULL);
85
86static 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
94static void map_release(struct kobject *kobj)
95{
96	struct uio_map *map = to_map(kobj);
97	kfree(map);
98}
99
100static 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
115static const struct sysfs_ops map_sysfs_ops = {
116	.show = map_type_show,
117};
118
119static struct kobj_type map_attr_type = {
120	.release	= map_release,
121	.sysfs_ops	= &map_sysfs_ops,
122	.default_attrs	= attrs,
123};
124
125struct 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
131static 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
139static ssize_t portio_start_show(struct uio_port *port, char *buf)
140{
141	return sprintf(buf, "0x%lx\n", port->start);
142}
143
144static ssize_t portio_size_show(struct uio_port *port, char *buf)
145{
146	return sprintf(buf, "0x%lx\n", port->size);
147}
148
149static 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
159struct 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
165static struct portio_sysfs_entry portio_name_attribute =
166	__ATTR(name, S_IRUGO, portio_name_show, NULL);
167static struct portio_sysfs_entry portio_start_attribute =
168	__ATTR(start, S_IRUGO, portio_start_show, NULL);
169static struct portio_sysfs_entry portio_size_attribute =
170	__ATTR(size, S_IRUGO, portio_size_show, NULL);
171static struct portio_sysfs_entry portio_porttype_attribute =
172	__ATTR(porttype, S_IRUGO, portio_porttype_show, NULL);
173
174static 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
182static void portio_release(struct kobject *kobj)
183{
184	struct uio_portio *portio = to_portio(kobj);
185	kfree(portio);
186}
187
188static 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
203static const struct sysfs_ops portio_sysfs_ops = {
204	.show = portio_type_show,
205};
206
207static struct kobj_type portio_attr_type = {
208	.release	= portio_release,
209	.sysfs_ops	= &portio_sysfs_ops,
210	.default_attrs	= portio_attrs,
211};
212
213static 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
228out:
229	mutex_unlock(&idev->info_lock);
230	return ret;
231}
232static DEVICE_ATTR_RO(name);
233
234static 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
249out:
250	mutex_unlock(&idev->info_lock);
251	return ret;
252}
253static DEVICE_ATTR_RO(version);
254
255static 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}
261static DEVICE_ATTR_RO(event);
262
263static struct attribute *uio_attrs[] = {
264	&dev_attr_name.attr,
265	&dev_attr_version.attr,
266	&dev_attr_event.attr,
267	NULL,
268};
269ATTRIBUTE_GROUPS(uio);
270
271/* UIO class infrastructure */
272static struct class uio_class = {
273	.name = "uio",
274	.dev_groups = uio_groups,
275};
276
277static bool uio_class_registered;
278
279/*
280 * device functions
281 */
282static 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
354err_portio:
355	pi--;
356err_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);
363err_map:
364	mi--;
365err_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
376static 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
399static 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
416static 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 */
427void 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}
435EXPORT_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 */
442static 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
454struct uio_listener {
455	struct uio_device *dev;
456	s32 event_count;
457};
458
459static 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	if (!idev) {
468		ret = -ENODEV;
469		mutex_unlock(&minor_lock);
470		goto out;
471	}
472	get_device(&idev->dev);
473	mutex_unlock(&minor_lock);
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
505err_infoopen:
506	kfree(listener);
507
508err_alloc_listener:
509	module_put(idev->owner);
510
511err_module_get:
512	put_device(&idev->dev);
513
514out:
515	return ret;
516}
517
518static 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
526static 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
543static __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
563static 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
618static 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
650out:
651	mutex_unlock(&idev->info_lock);
652	return retval ? retval : sizeof(s32);
653}
654
655static 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
667static 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
702out:
703	mutex_unlock(&idev->info_lock);
704
705	return ret;
706}
707
708static const struct vm_operations_struct uio_logical_vm_ops = {
709	.fault = uio_vma_fault,
710};
711
712static 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
719static const struct vm_operations_struct uio_physical_vm_ops = {
720#ifdef CONFIG_HAVE_IOREMAP_PROT
721	.access = generic_access_phys,
722#endif
723};
724
725static 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
760static 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
816static 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
828static 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;
855out_put:
856	kobject_put(&cdev->kobj);
857out_unregister:
858	unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
859out:
860	return result;
861}
862
863static void uio_major_cleanup(void)
864{
865	unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
866	cdev_del(uio_cdev);
867}
868
869static 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
888err_class_register:
889	uio_major_cleanup();
890exit:
891	return ret;
892}
893
894static void release_uio_class(void)
895{
896	uio_class_registered = false;
897	class_unregister(&uio_class);
898	uio_major_cleanup();
899}
900
901static 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 */
916int __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
988err_request_irq:
989	uio_dev_del_attributes(idev);
990err_uio_dev_add_attributes:
991	device_del(&idev->dev);
992err_device_create:
993	uio_free_minor(idev->minor);
994	put_device(&idev->dev);
995	return ret;
996}
997EXPORT_SYMBOL_GPL(__uio_register_device);
998
999static 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 */
1012int __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}
1035EXPORT_SYMBOL_GPL(__devm_uio_register_device);
1036
1037/**
1038 * uio_unregister_device - unregister a industrial IO device
1039 * @info:	UIO device capabilities
1040 *
1041 */
1042void 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	uio_free_minor(minor);
1066	device_unregister(&idev->dev);
1067
1068	return;
1069}
1070EXPORT_SYMBOL_GPL(uio_unregister_device);
1071
1072static int __init uio_init(void)
1073{
1074	return init_uio_class();
1075}
1076
1077static void __exit uio_exit(void)
1078{
1079	release_uio_class();
1080	idr_destroy(&uio_idr);
1081}
1082
1083module_init(uio_init)
1084module_exit(uio_exit)
1085MODULE_LICENSE("GPL v2");
1086