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 = -ENOMEM;
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(struct uio_device *idev)
417{
418 mutex_lock(&minor_lock);
419 idr_remove(&uio_idr, idev->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 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
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);
994 put_device(&idev->dev);
995 return ret;
996}
997EXPORT_SYMBOL_GPL(__uio_register_device);
998
999/**
1000 * uio_unregister_device - unregister a industrial IO device
1001 * @info: UIO device capabilities
1002 *
1003 */
1004void uio_unregister_device(struct uio_info *info)
1005{
1006 struct uio_device *idev;
1007
1008 if (!info || !info->uio_dev)
1009 return;
1010
1011 idev = info->uio_dev;
1012
1013 uio_free_minor(idev);
1014
1015 mutex_lock(&idev->info_lock);
1016 uio_dev_del_attributes(idev);
1017
1018 if (info->irq && info->irq != UIO_IRQ_CUSTOM)
1019 free_irq(info->irq, idev);
1020
1021 idev->info = NULL;
1022 mutex_unlock(&idev->info_lock);
1023
1024 wake_up_interruptible(&idev->wait);
1025 kill_fasync(&idev->async_queue, SIGIO, POLL_HUP);
1026
1027 device_unregister(&idev->dev);
1028
1029 return;
1030}
1031EXPORT_SYMBOL_GPL(uio_unregister_device);
1032
1033static int __init uio_init(void)
1034{
1035 return init_uio_class();
1036}
1037
1038static void __exit uio_exit(void)
1039{
1040 release_uio_class();
1041 idr_destroy(&uio_idr);
1042}
1043
1044module_init(uio_init)
1045module_exit(uio_exit)
1046MODULE_LICENSE("GPL v2");
1047