xref: /kernel/linux/linux-6.6/drivers/uio/uio.c (revision 62306a36) 
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 *map_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};
93ATTRIBUTE_GROUPS(map);
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_groups	= map_groups,
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};
182ATTRIBUTE_GROUPS(portio);
183
184static void portio_release(struct kobject *kobj)
185{
186	struct uio_portio *portio = to_portio(kobj);
187	kfree(portio);
188}
189
190static ssize_t portio_type_show(struct kobject *kobj, struct attribute *attr,
191			     char *buf)
192{
193	struct uio_portio *portio = to_portio(kobj);
194	struct uio_port *port = portio->port;
195	struct portio_sysfs_entry *entry;
196
197	entry = container_of(attr, struct portio_sysfs_entry, attr);
198
199	if (!entry->show)
200		return -EIO;
201
202	return entry->show(port, buf);
203}
204
205static const struct sysfs_ops portio_sysfs_ops = {
206	.show = portio_type_show,
207};
208
209static struct kobj_type portio_attr_type = {
210	.release	= portio_release,
211	.sysfs_ops	= &portio_sysfs_ops,
212	.default_groups	= portio_groups,
213};
214
215static ssize_t name_show(struct device *dev,
216			 struct device_attribute *attr, char *buf)
217{
218	struct uio_device *idev = dev_get_drvdata(dev);
219	int ret;
220
221	mutex_lock(&idev->info_lock);
222	if (!idev->info) {
223		ret = -EINVAL;
224		dev_err(dev, "the device has been unregistered\n");
225		goto out;
226	}
227
228	ret = sprintf(buf, "%s\n", idev->info->name);
229
230out:
231	mutex_unlock(&idev->info_lock);
232	return ret;
233}
234static DEVICE_ATTR_RO(name);
235
236static ssize_t version_show(struct device *dev,
237			    struct device_attribute *attr, char *buf)
238{
239	struct uio_device *idev = dev_get_drvdata(dev);
240	int ret;
241
242	mutex_lock(&idev->info_lock);
243	if (!idev->info) {
244		ret = -EINVAL;
245		dev_err(dev, "the device has been unregistered\n");
246		goto out;
247	}
248
249	ret = sprintf(buf, "%s\n", idev->info->version);
250
251out:
252	mutex_unlock(&idev->info_lock);
253	return ret;
254}
255static DEVICE_ATTR_RO(version);
256
257static ssize_t event_show(struct device *dev,
258			  struct device_attribute *attr, char *buf)
259{
260	struct uio_device *idev = dev_get_drvdata(dev);
261	return sprintf(buf, "%u\n", (unsigned int)atomic_read(&idev->event));
262}
263static DEVICE_ATTR_RO(event);
264
265static struct attribute *uio_attrs[] = {
266	&dev_attr_name.attr,
267	&dev_attr_version.attr,
268	&dev_attr_event.attr,
269	NULL,
270};
271ATTRIBUTE_GROUPS(uio);
272
273/* UIO class infrastructure */
274static struct class uio_class = {
275	.name = "uio",
276	.dev_groups = uio_groups,
277};
278
279static bool uio_class_registered;
280
281/*
282 * device functions
283 */
284static int uio_dev_add_attributes(struct uio_device *idev)
285{
286	int ret;
287	int mi, pi;
288	int map_found = 0;
289	int portio_found = 0;
290	struct uio_mem *mem;
291	struct uio_map *map;
292	struct uio_port *port;
293	struct uio_portio *portio;
294
295	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
296		mem = &idev->info->mem[mi];
297		if (mem->size == 0)
298			break;
299		if (!map_found) {
300			map_found = 1;
301			idev->map_dir = kobject_create_and_add("maps",
302							&idev->dev.kobj);
303			if (!idev->map_dir) {
304				ret = -ENOMEM;
305				goto err_map;
306			}
307		}
308		map = kzalloc(sizeof(*map), GFP_KERNEL);
309		if (!map) {
310			ret = -ENOMEM;
311			goto err_map;
312		}
313		kobject_init(&map->kobj, &map_attr_type);
314		map->mem = mem;
315		mem->map = map;
316		ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
317		if (ret)
318			goto err_map_kobj;
319		ret = kobject_uevent(&map->kobj, KOBJ_ADD);
320		if (ret)
321			goto err_map_kobj;
322	}
323
324	for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
325		port = &idev->info->port[pi];
326		if (port->size == 0)
327			break;
328		if (!portio_found) {
329			portio_found = 1;
330			idev->portio_dir = kobject_create_and_add("portio",
331							&idev->dev.kobj);
332			if (!idev->portio_dir) {
333				ret = -ENOMEM;
334				goto err_portio;
335			}
336		}
337		portio = kzalloc(sizeof(*portio), GFP_KERNEL);
338		if (!portio) {
339			ret = -ENOMEM;
340			goto err_portio;
341		}
342		kobject_init(&portio->kobj, &portio_attr_type);
343		portio->port = port;
344		port->portio = portio;
345		ret = kobject_add(&portio->kobj, idev->portio_dir,
346							"port%d", pi);
347		if (ret)
348			goto err_portio_kobj;
349		ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
350		if (ret)
351			goto err_portio_kobj;
352	}
353
354	return 0;
355
356err_portio:
357	pi--;
358err_portio_kobj:
359	for (; pi >= 0; pi--) {
360		port = &idev->info->port[pi];
361		portio = port->portio;
362		kobject_put(&portio->kobj);
363	}
364	kobject_put(idev->portio_dir);
365err_map:
366	mi--;
367err_map_kobj:
368	for (; mi >= 0; mi--) {
369		mem = &idev->info->mem[mi];
370		map = mem->map;
371		kobject_put(&map->kobj);
372	}
373	kobject_put(idev->map_dir);
374	dev_err(&idev->dev, "error creating sysfs files (%d)\n", ret);
375	return ret;
376}
377
378static void uio_dev_del_attributes(struct uio_device *idev)
379{
380	int i;
381	struct uio_mem *mem;
382	struct uio_port *port;
383
384	for (i = 0; i < MAX_UIO_MAPS; i++) {
385		mem = &idev->info->mem[i];
386		if (mem->size == 0)
387			break;
388		kobject_put(&mem->map->kobj);
389	}
390	kobject_put(idev->map_dir);
391
392	for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
393		port = &idev->info->port[i];
394		if (port->size == 0)
395			break;
396		kobject_put(&port->portio->kobj);
397	}
398	kobject_put(idev->portio_dir);
399}
400
401static int uio_get_minor(struct uio_device *idev)
402{
403	int retval;
404
405	mutex_lock(&minor_lock);
406	retval = idr_alloc(&uio_idr, idev, 0, UIO_MAX_DEVICES, GFP_KERNEL);
407	if (retval >= 0) {
408		idev->minor = retval;
409		retval = 0;
410	} else if (retval == -ENOSPC) {
411		dev_err(&idev->dev, "too many uio devices\n");
412		retval = -EINVAL;
413	}
414	mutex_unlock(&minor_lock);
415	return retval;
416}
417
418static void uio_free_minor(unsigned long minor)
419{
420	mutex_lock(&minor_lock);
421	idr_remove(&uio_idr, minor);
422	mutex_unlock(&minor_lock);
423}
424
425/**
426 * uio_event_notify - trigger an interrupt event
427 * @info: UIO device capabilities
428 */
429void uio_event_notify(struct uio_info *info)
430{
431	struct uio_device *idev = info->uio_dev;
432
433	atomic_inc(&idev->event);
434	wake_up_interruptible(&idev->wait);
435	kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
436}
437EXPORT_SYMBOL_GPL(uio_event_notify);
438
439/**
440 * uio_interrupt - hardware interrupt handler
441 * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
442 * @dev_id: Pointer to the devices uio_device structure
443 */
444static irqreturn_t uio_interrupt(int irq, void *dev_id)
445{
446	struct uio_device *idev = (struct uio_device *)dev_id;
447	irqreturn_t ret;
448
449	ret = idev->info->handler(irq, idev->info);
450	if (ret == IRQ_HANDLED)
451		uio_event_notify(idev->info);
452
453	return ret;
454}
455
456struct uio_listener {
457	struct uio_device *dev;
458	s32 event_count;
459};
460
461static int uio_open(struct inode *inode, struct file *filep)
462{
463	struct uio_device *idev;
464	struct uio_listener *listener;
465	int ret = 0;
466
467	mutex_lock(&minor_lock);
468	idev = idr_find(&uio_idr, iminor(inode));
469	if (!idev) {
470		ret = -ENODEV;
471		mutex_unlock(&minor_lock);
472		goto out;
473	}
474	get_device(&idev->dev);
475	mutex_unlock(&minor_lock);
476
477	if (!try_module_get(idev->owner)) {
478		ret = -ENODEV;
479		goto err_module_get;
480	}
481
482	listener = kmalloc(sizeof(*listener), GFP_KERNEL);
483	if (!listener) {
484		ret = -ENOMEM;
485		goto err_alloc_listener;
486	}
487
488	listener->dev = idev;
489	listener->event_count = atomic_read(&idev->event);
490	filep->private_data = listener;
491
492	mutex_lock(&idev->info_lock);
493	if (!idev->info) {
494		mutex_unlock(&idev->info_lock);
495		ret = -EINVAL;
496		goto err_infoopen;
497	}
498
499	if (idev->info->open)
500		ret = idev->info->open(idev->info, inode);
501	mutex_unlock(&idev->info_lock);
502	if (ret)
503		goto err_infoopen;
504
505	return 0;
506
507err_infoopen:
508	kfree(listener);
509
510err_alloc_listener:
511	module_put(idev->owner);
512
513err_module_get:
514	put_device(&idev->dev);
515
516out:
517	return ret;
518}
519
520static int uio_fasync(int fd, struct file *filep, int on)
521{
522	struct uio_listener *listener = filep->private_data;
523	struct uio_device *idev = listener->dev;
524
525	return fasync_helper(fd, filep, on, &idev->async_queue);
526}
527
528static int uio_release(struct inode *inode, struct file *filep)
529{
530	int ret = 0;
531	struct uio_listener *listener = filep->private_data;
532	struct uio_device *idev = listener->dev;
533
534	mutex_lock(&idev->info_lock);
535	if (idev->info && idev->info->release)
536		ret = idev->info->release(idev->info, inode);
537	mutex_unlock(&idev->info_lock);
538
539	module_put(idev->owner);
540	kfree(listener);
541	put_device(&idev->dev);
542	return ret;
543}
544
545static __poll_t uio_poll(struct file *filep, poll_table *wait)
546{
547	struct uio_listener *listener = filep->private_data;
548	struct uio_device *idev = listener->dev;
549	__poll_t ret = 0;
550
551	mutex_lock(&idev->info_lock);
552	if (!idev->info || !idev->info->irq)
553		ret = -EIO;
554	mutex_unlock(&idev->info_lock);
555
556	if (ret)
557		return ret;
558
559	poll_wait(filep, &idev->wait, wait);
560	if (listener->event_count != atomic_read(&idev->event))
561		return EPOLLIN | EPOLLRDNORM;
562	return 0;
563}
564
565static ssize_t uio_read(struct file *filep, char __user *buf,
566			size_t count, loff_t *ppos)
567{
568	struct uio_listener *listener = filep->private_data;
569	struct uio_device *idev = listener->dev;
570	DECLARE_WAITQUEUE(wait, current);
571	ssize_t retval = 0;
572	s32 event_count;
573
574	if (count != sizeof(s32))
575		return -EINVAL;
576
577	add_wait_queue(&idev->wait, &wait);
578
579	do {
580		mutex_lock(&idev->info_lock);
581		if (!idev->info || !idev->info->irq) {
582			retval = -EIO;
583			mutex_unlock(&idev->info_lock);
584			break;
585		}
586		mutex_unlock(&idev->info_lock);
587
588		set_current_state(TASK_INTERRUPTIBLE);
589
590		event_count = atomic_read(&idev->event);
591		if (event_count != listener->event_count) {
592			__set_current_state(TASK_RUNNING);
593			if (copy_to_user(buf, &event_count, count))
594				retval = -EFAULT;
595			else {
596				listener->event_count = event_count;
597				retval = count;
598			}
599			break;
600		}
601
602		if (filep->f_flags & O_NONBLOCK) {
603			retval = -EAGAIN;
604			break;
605		}
606
607		if (signal_pending(current)) {
608			retval = -ERESTARTSYS;
609			break;
610		}
611		schedule();
612	} while (1);
613
614	__set_current_state(TASK_RUNNING);
615	remove_wait_queue(&idev->wait, &wait);
616
617	return retval;
618}
619
620static ssize_t uio_write(struct file *filep, const char __user *buf,
621			size_t count, loff_t *ppos)
622{
623	struct uio_listener *listener = filep->private_data;
624	struct uio_device *idev = listener->dev;
625	ssize_t retval;
626	s32 irq_on;
627
628	if (count != sizeof(s32))
629		return -EINVAL;
630
631	if (copy_from_user(&irq_on, buf, count))
632		return -EFAULT;
633
634	mutex_lock(&idev->info_lock);
635	if (!idev->info) {
636		retval = -EINVAL;
637		goto out;
638	}
639
640	if (!idev->info->irq) {
641		retval = -EIO;
642		goto out;
643	}
644
645	if (!idev->info->irqcontrol) {
646		retval = -ENOSYS;
647		goto out;
648	}
649
650	retval = idev->info->irqcontrol(idev->info, irq_on);
651
652out:
653	mutex_unlock(&idev->info_lock);
654	return retval ? retval : sizeof(s32);
655}
656
657static int uio_find_mem_index(struct vm_area_struct *vma)
658{
659	struct uio_device *idev = vma->vm_private_data;
660
661	if (vma->vm_pgoff < MAX_UIO_MAPS) {
662		if (idev->info->mem[vma->vm_pgoff].size == 0)
663			return -1;
664		return (int)vma->vm_pgoff;
665	}
666	return -1;
667}
668
669static vm_fault_t uio_vma_fault(struct vm_fault *vmf)
670{
671	struct uio_device *idev = vmf->vma->vm_private_data;
672	struct page *page;
673	unsigned long offset;
674	void *addr;
675	vm_fault_t ret = 0;
676	int mi;
677
678	mutex_lock(&idev->info_lock);
679	if (!idev->info) {
680		ret = VM_FAULT_SIGBUS;
681		goto out;
682	}
683
684	mi = uio_find_mem_index(vmf->vma);
685	if (mi < 0) {
686		ret = VM_FAULT_SIGBUS;
687		goto out;
688	}
689
690	/*
691	 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
692	 * to use mem[N].
693	 */
694	offset = (vmf->pgoff - mi) << PAGE_SHIFT;
695
696	addr = (void *)(unsigned long)idev->info->mem[mi].addr + offset;
697	if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
698		page = virt_to_page(addr);
699	else
700		page = vmalloc_to_page(addr);
701	get_page(page);
702	vmf->page = page;
703
704out:
705	mutex_unlock(&idev->info_lock);
706
707	return ret;
708}
709
710static const struct vm_operations_struct uio_logical_vm_ops = {
711	.fault = uio_vma_fault,
712};
713
714static int uio_mmap_logical(struct vm_area_struct *vma)
715{
716	vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP);
717	vma->vm_ops = &uio_logical_vm_ops;
718	return 0;
719}
720
721static const struct vm_operations_struct uio_physical_vm_ops = {
722#ifdef CONFIG_HAVE_IOREMAP_PROT
723	.access = generic_access_phys,
724#endif
725};
726
727static int uio_mmap_physical(struct vm_area_struct *vma)
728{
729	struct uio_device *idev = vma->vm_private_data;
730	int mi = uio_find_mem_index(vma);
731	struct uio_mem *mem;
732
733	if (mi < 0)
734		return -EINVAL;
735	mem = idev->info->mem + mi;
736
737	if (mem->addr & ~PAGE_MASK)
738		return -ENODEV;
739	if (vma->vm_end - vma->vm_start > mem->size)
740		return -EINVAL;
741
742	vma->vm_ops = &uio_physical_vm_ops;
743	if (idev->info->mem[mi].memtype == UIO_MEM_PHYS)
744		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
745
746	/*
747	 * We cannot use the vm_iomap_memory() helper here,
748	 * because vma->vm_pgoff is the map index we looked
749	 * up above in uio_find_mem_index(), rather than an
750	 * actual page offset into the mmap.
751	 *
752	 * So we just do the physical mmap without a page
753	 * offset.
754	 */
755	return remap_pfn_range(vma,
756			       vma->vm_start,
757			       mem->addr >> PAGE_SHIFT,
758			       vma->vm_end - vma->vm_start,
759			       vma->vm_page_prot);
760}
761
762static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
763{
764	struct uio_listener *listener = filep->private_data;
765	struct uio_device *idev = listener->dev;
766	int mi;
767	unsigned long requested_pages, actual_pages;
768	int ret = 0;
769
770	if (vma->vm_end < vma->vm_start)
771		return -EINVAL;
772
773	vma->vm_private_data = idev;
774
775	mutex_lock(&idev->info_lock);
776	if (!idev->info) {
777		ret = -EINVAL;
778		goto out;
779	}
780
781	mi = uio_find_mem_index(vma);
782	if (mi < 0) {
783		ret = -EINVAL;
784		goto out;
785	}
786
787	requested_pages = vma_pages(vma);
788	actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
789			+ idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
790	if (requested_pages > actual_pages) {
791		ret = -EINVAL;
792		goto out;
793	}
794
795	if (idev->info->mmap) {
796		ret = idev->info->mmap(idev->info, vma);
797		goto out;
798	}
799
800	switch (idev->info->mem[mi].memtype) {
801	case UIO_MEM_IOVA:
802	case UIO_MEM_PHYS:
803		ret = uio_mmap_physical(vma);
804		break;
805	case UIO_MEM_LOGICAL:
806	case UIO_MEM_VIRTUAL:
807		ret = uio_mmap_logical(vma);
808		break;
809	default:
810		ret = -EINVAL;
811	}
812
813 out:
814	mutex_unlock(&idev->info_lock);
815	return ret;
816}
817
818static const struct file_operations uio_fops = {
819	.owner		= THIS_MODULE,
820	.open		= uio_open,
821	.release	= uio_release,
822	.read		= uio_read,
823	.write		= uio_write,
824	.mmap		= uio_mmap,
825	.poll		= uio_poll,
826	.fasync		= uio_fasync,
827	.llseek		= noop_llseek,
828};
829
830static int uio_major_init(void)
831{
832	static const char name[] = "uio";
833	struct cdev *cdev = NULL;
834	dev_t uio_dev = 0;
835	int result;
836
837	result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name);
838	if (result)
839		goto out;
840
841	result = -ENOMEM;
842	cdev = cdev_alloc();
843	if (!cdev)
844		goto out_unregister;
845
846	cdev->owner = THIS_MODULE;
847	cdev->ops = &uio_fops;
848	kobject_set_name(&cdev->kobj, "%s", name);
849
850	result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES);
851	if (result)
852		goto out_put;
853
854	uio_major = MAJOR(uio_dev);
855	uio_cdev = cdev;
856	return 0;
857out_put:
858	kobject_put(&cdev->kobj);
859out_unregister:
860	unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
861out:
862	return result;
863}
864
865static void uio_major_cleanup(void)
866{
867	unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
868	cdev_del(uio_cdev);
869}
870
871static int init_uio_class(void)
872{
873	int ret;
874
875	/* This is the first time in here, set everything up properly */
876	ret = uio_major_init();
877	if (ret)
878		goto exit;
879
880	ret = class_register(&uio_class);
881	if (ret) {
882		printk(KERN_ERR "class_register failed for uio\n");
883		goto err_class_register;
884	}
885
886	uio_class_registered = true;
887
888	return 0;
889
890err_class_register:
891	uio_major_cleanup();
892exit:
893	return ret;
894}
895
896static void release_uio_class(void)
897{
898	uio_class_registered = false;
899	class_unregister(&uio_class);
900	uio_major_cleanup();
901}
902
903static void uio_device_release(struct device *dev)
904{
905	struct uio_device *idev = dev_get_drvdata(dev);
906
907	kfree(idev);
908}
909
910/**
911 * __uio_register_device - register a new userspace IO device
912 * @owner:	module that creates the new device
913 * @parent:	parent device
914 * @info:	UIO device capabilities
915 *
916 * returns zero on success or a negative error code.
917 */
918int __uio_register_device(struct module *owner,
919			  struct device *parent,
920			  struct uio_info *info)
921{
922	struct uio_device *idev;
923	int ret = 0;
924
925	if (!uio_class_registered)
926		return -EPROBE_DEFER;
927
928	if (!parent || !info || !info->name || !info->version)
929		return -EINVAL;
930
931	info->uio_dev = NULL;
932
933	idev = kzalloc(sizeof(*idev), GFP_KERNEL);
934	if (!idev) {
935		return -ENOMEM;
936	}
937
938	idev->owner = owner;
939	idev->info = info;
940	mutex_init(&idev->info_lock);
941	init_waitqueue_head(&idev->wait);
942	atomic_set(&idev->event, 0);
943
944	ret = uio_get_minor(idev);
945	if (ret) {
946		kfree(idev);
947		return ret;
948	}
949
950	device_initialize(&idev->dev);
951	idev->dev.devt = MKDEV(uio_major, idev->minor);
952	idev->dev.class = &uio_class;
953	idev->dev.parent = parent;
954	idev->dev.release = uio_device_release;
955	dev_set_drvdata(&idev->dev, idev);
956
957	ret = dev_set_name(&idev->dev, "uio%d", idev->minor);
958	if (ret)
959		goto err_device_create;
960
961	ret = device_add(&idev->dev);
962	if (ret)
963		goto err_device_create;
964
965	ret = uio_dev_add_attributes(idev);
966	if (ret)
967		goto err_uio_dev_add_attributes;
968
969	info->uio_dev = idev;
970
971	if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) {
972		/*
973		 * Note that we deliberately don't use devm_request_irq
974		 * here. The parent module can unregister the UIO device
975		 * and call pci_disable_msi, which requires that this
976		 * irq has been freed. However, the device may have open
977		 * FDs at the time of unregister and therefore may not be
978		 * freed until they are released.
979		 */
980		ret = request_irq(info->irq, uio_interrupt,
981				  info->irq_flags, info->name, idev);
982		if (ret) {
983			info->uio_dev = NULL;
984			goto err_request_irq;
985		}
986	}
987
988	return 0;
989
990err_request_irq:
991	uio_dev_del_attributes(idev);
992err_uio_dev_add_attributes:
993	device_del(&idev->dev);
994err_device_create:
995	uio_free_minor(idev->minor);
996	put_device(&idev->dev);
997	return ret;
998}
999EXPORT_SYMBOL_GPL(__uio_register_device);
1000
1001static void devm_uio_unregister_device(struct device *dev, void *res)
1002{
1003	uio_unregister_device(*(struct uio_info **)res);
1004}
1005
1006/**
1007 * __devm_uio_register_device - Resource managed uio_register_device()
1008 * @owner:	module that creates the new device
1009 * @parent:	parent device
1010 * @info:	UIO device capabilities
1011 *
1012 * returns zero on success or a negative error code.
1013 */
1014int __devm_uio_register_device(struct module *owner,
1015			       struct device *parent,
1016			       struct uio_info *info)
1017{
1018	struct uio_info **ptr;
1019	int ret;
1020
1021	ptr = devres_alloc(devm_uio_unregister_device, sizeof(*ptr),
1022			   GFP_KERNEL);
1023	if (!ptr)
1024		return -ENOMEM;
1025
1026	*ptr = info;
1027	ret = __uio_register_device(owner, parent, info);
1028	if (ret) {
1029		devres_free(ptr);
1030		return ret;
1031	}
1032
1033	devres_add(parent, ptr);
1034
1035	return 0;
1036}
1037EXPORT_SYMBOL_GPL(__devm_uio_register_device);
1038
1039/**
1040 * uio_unregister_device - unregister a industrial IO device
1041 * @info:	UIO device capabilities
1042 *
1043 */
1044void uio_unregister_device(struct uio_info *info)
1045{
1046	struct uio_device *idev;
1047	unsigned long minor;
1048
1049	if (!info || !info->uio_dev)
1050		return;
1051
1052	idev = info->uio_dev;
1053	minor = idev->minor;
1054
1055	mutex_lock(&idev->info_lock);
1056	uio_dev_del_attributes(idev);
1057
1058	if (info->irq && info->irq != UIO_IRQ_CUSTOM)
1059		free_irq(info->irq, idev);
1060
1061	idev->info = NULL;
1062	mutex_unlock(&idev->info_lock);
1063
1064	wake_up_interruptible(&idev->wait);
1065	kill_fasync(&idev->async_queue, SIGIO, POLL_HUP);
1066
1067	uio_free_minor(minor);
1068	device_unregister(&idev->dev);
1069
1070	return;
1071}
1072EXPORT_SYMBOL_GPL(uio_unregister_device);
1073
1074static int __init uio_init(void)
1075{
1076	return init_uio_class();
1077}
1078
1079static void __exit uio_exit(void)
1080{
1081	release_uio_class();
1082	idr_destroy(&uio_idr);
1083}
1084
1085module_init(uio_init)
1086module_exit(uio_exit)
1087MODULE_LICENSE("GPL v2");
1088