1 /*
2 * drivers/uio/uio.c
3 *
4 * Copyright(C) 2005, Benedikt Spranger <b.spranger@linutronix.de>
5 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
6 * Copyright(C) 2006, Hans J. Koch <hjk@hansjkoch.de>
7 * Copyright(C) 2006, Greg Kroah-Hartman <greg@kroah.com>
8 *
9 * Userspace IO
10 *
11 * Base Functions
12 *
13 * Licensed under the GPLv2 only.
14 */
15
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/poll.h>
19 #include <linux/device.h>
20 #include <linux/slab.h>
21 #include <linux/mm.h>
22 #include <linux/idr.h>
23 #include <linux/sched.h>
24 #include <linux/string.h>
25 #include <linux/kobject.h>
26 #include <linux/cdev.h>
27 #include <linux/uio_driver.h>
28
29 #define UIO_MAX_DEVICES (1U << MINORBITS)
30
31 static int uio_major;
32 static struct cdev *uio_cdev;
33 static DEFINE_IDR(uio_idr);
34 static const struct file_operations uio_fops;
35
36 /* Protect idr accesses */
37 static DEFINE_MUTEX(minor_lock);
38
39 /*
40 * attributes
41 */
42
43 struct uio_map {
44 struct kobject kobj;
45 struct uio_mem *mem;
46 };
47 #define to_map(map) container_of(map, struct uio_map, kobj)
48
map_name_show(struct uio_mem * mem,char * buf)49 static ssize_t map_name_show(struct uio_mem *mem, char *buf)
50 {
51 if (unlikely(!mem->name))
52 mem->name = "";
53
54 return sprintf(buf, "%s\n", mem->name);
55 }
56
map_addr_show(struct uio_mem * mem,char * buf)57 static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
58 {
59 return sprintf(buf, "%pa\n", &mem->addr);
60 }
61
map_size_show(struct uio_mem * mem,char * buf)62 static ssize_t map_size_show(struct uio_mem *mem, char *buf)
63 {
64 return sprintf(buf, "%pa\n", &mem->size);
65 }
66
map_offset_show(struct uio_mem * mem,char * buf)67 static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
68 {
69 return sprintf(buf, "0x%llx\n", (unsigned long long)mem->addr & ~PAGE_MASK);
70 }
71
72 struct map_sysfs_entry {
73 struct attribute attr;
74 ssize_t (*show)(struct uio_mem *, char *);
75 ssize_t (*store)(struct uio_mem *, const char *, size_t);
76 };
77
78 static struct map_sysfs_entry name_attribute =
79 __ATTR(name, S_IRUGO, map_name_show, NULL);
80 static struct map_sysfs_entry addr_attribute =
81 __ATTR(addr, S_IRUGO, map_addr_show, NULL);
82 static struct map_sysfs_entry size_attribute =
83 __ATTR(size, S_IRUGO, map_size_show, NULL);
84 static struct map_sysfs_entry offset_attribute =
85 __ATTR(offset, S_IRUGO, map_offset_show, NULL);
86
87 static struct attribute *attrs[] = {
88 &name_attribute.attr,
89 &addr_attribute.attr,
90 &size_attribute.attr,
91 &offset_attribute.attr,
92 NULL, /* need to NULL terminate the list of attributes */
93 };
94
map_release(struct kobject * kobj)95 static void map_release(struct kobject *kobj)
96 {
97 struct uio_map *map = to_map(kobj);
98 kfree(map);
99 }
100
map_type_show(struct kobject * kobj,struct attribute * attr,char * buf)101 static ssize_t map_type_show(struct kobject *kobj, struct attribute *attr,
102 char *buf)
103 {
104 struct uio_map *map = to_map(kobj);
105 struct uio_mem *mem = map->mem;
106 struct map_sysfs_entry *entry;
107
108 entry = container_of(attr, struct map_sysfs_entry, attr);
109
110 if (!entry->show)
111 return -EIO;
112
113 return entry->show(mem, buf);
114 }
115
116 static const struct sysfs_ops map_sysfs_ops = {
117 .show = map_type_show,
118 };
119
120 static struct kobj_type map_attr_type = {
121 .release = map_release,
122 .sysfs_ops = &map_sysfs_ops,
123 .default_attrs = attrs,
124 };
125
126 struct uio_portio {
127 struct kobject kobj;
128 struct uio_port *port;
129 };
130 #define to_portio(portio) container_of(portio, struct uio_portio, kobj)
131
portio_name_show(struct uio_port * port,char * buf)132 static ssize_t portio_name_show(struct uio_port *port, char *buf)
133 {
134 if (unlikely(!port->name))
135 port->name = "";
136
137 return sprintf(buf, "%s\n", port->name);
138 }
139
portio_start_show(struct uio_port * port,char * buf)140 static ssize_t portio_start_show(struct uio_port *port, char *buf)
141 {
142 return sprintf(buf, "0x%lx\n", port->start);
143 }
144
portio_size_show(struct uio_port * port,char * buf)145 static ssize_t portio_size_show(struct uio_port *port, char *buf)
146 {
147 return sprintf(buf, "0x%lx\n", port->size);
148 }
149
portio_porttype_show(struct uio_port * port,char * buf)150 static ssize_t portio_porttype_show(struct uio_port *port, char *buf)
151 {
152 const char *porttypes[] = {"none", "x86", "gpio", "other"};
153
154 if ((port->porttype < 0) || (port->porttype > UIO_PORT_OTHER))
155 return -EINVAL;
156
157 return sprintf(buf, "port_%s\n", porttypes[port->porttype]);
158 }
159
160 struct portio_sysfs_entry {
161 struct attribute attr;
162 ssize_t (*show)(struct uio_port *, char *);
163 ssize_t (*store)(struct uio_port *, const char *, size_t);
164 };
165
166 static struct portio_sysfs_entry portio_name_attribute =
167 __ATTR(name, S_IRUGO, portio_name_show, NULL);
168 static struct portio_sysfs_entry portio_start_attribute =
169 __ATTR(start, S_IRUGO, portio_start_show, NULL);
170 static struct portio_sysfs_entry portio_size_attribute =
171 __ATTR(size, S_IRUGO, portio_size_show, NULL);
172 static struct portio_sysfs_entry portio_porttype_attribute =
173 __ATTR(porttype, S_IRUGO, portio_porttype_show, NULL);
174
175 static struct attribute *portio_attrs[] = {
176 &portio_name_attribute.attr,
177 &portio_start_attribute.attr,
178 &portio_size_attribute.attr,
179 &portio_porttype_attribute.attr,
180 NULL,
181 };
182
portio_release(struct kobject * kobj)183 static void portio_release(struct kobject *kobj)
184 {
185 struct uio_portio *portio = to_portio(kobj);
186 kfree(portio);
187 }
188
portio_type_show(struct kobject * kobj,struct attribute * attr,char * buf)189 static ssize_t portio_type_show(struct kobject *kobj, struct attribute *attr,
190 char *buf)
191 {
192 struct uio_portio *portio = to_portio(kobj);
193 struct uio_port *port = portio->port;
194 struct portio_sysfs_entry *entry;
195
196 entry = container_of(attr, struct portio_sysfs_entry, attr);
197
198 if (!entry->show)
199 return -EIO;
200
201 return entry->show(port, buf);
202 }
203
204 static const struct sysfs_ops portio_sysfs_ops = {
205 .show = portio_type_show,
206 };
207
208 static struct kobj_type portio_attr_type = {
209 .release = portio_release,
210 .sysfs_ops = &portio_sysfs_ops,
211 .default_attrs = portio_attrs,
212 };
213
name_show(struct device * dev,struct device_attribute * attr,char * buf)214 static ssize_t name_show(struct device *dev,
215 struct device_attribute *attr, char *buf)
216 {
217 struct uio_device *idev = dev_get_drvdata(dev);
218 return sprintf(buf, "%s\n", idev->info->name);
219 }
220 static DEVICE_ATTR_RO(name);
221
version_show(struct device * dev,struct device_attribute * attr,char * buf)222 static ssize_t version_show(struct device *dev,
223 struct device_attribute *attr, char *buf)
224 {
225 struct uio_device *idev = dev_get_drvdata(dev);
226 return sprintf(buf, "%s\n", idev->info->version);
227 }
228 static DEVICE_ATTR_RO(version);
229
event_show(struct device * dev,struct device_attribute * attr,char * buf)230 static ssize_t event_show(struct device *dev,
231 struct device_attribute *attr, char *buf)
232 {
233 struct uio_device *idev = dev_get_drvdata(dev);
234 return sprintf(buf, "%u\n", (unsigned int)atomic_read(&idev->event));
235 }
236 static DEVICE_ATTR_RO(event);
237
238 static struct attribute *uio_attrs[] = {
239 &dev_attr_name.attr,
240 &dev_attr_version.attr,
241 &dev_attr_event.attr,
242 NULL,
243 };
244 ATTRIBUTE_GROUPS(uio);
245
246 /* UIO class infrastructure */
247 static struct class uio_class = {
248 .name = "uio",
249 .dev_groups = uio_groups,
250 };
251
252 bool uio_class_registered;
253
254 /*
255 * device functions
256 */
uio_dev_add_attributes(struct uio_device * idev)257 static int uio_dev_add_attributes(struct uio_device *idev)
258 {
259 int ret;
260 int mi, pi;
261 int map_found = 0;
262 int portio_found = 0;
263 struct uio_mem *mem;
264 struct uio_map *map;
265 struct uio_port *port;
266 struct uio_portio *portio;
267
268 for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
269 mem = &idev->info->mem[mi];
270 if (mem->size == 0)
271 break;
272 if (!map_found) {
273 map_found = 1;
274 idev->map_dir = kobject_create_and_add("maps",
275 &idev->dev->kobj);
276 if (!idev->map_dir)
277 goto err_map;
278 }
279 map = kzalloc(sizeof(*map), GFP_KERNEL);
280 if (!map)
281 goto err_map_kobj;
282 kobject_init(&map->kobj, &map_attr_type);
283 map->mem = mem;
284 mem->map = map;
285 ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
286 if (ret)
287 goto err_map_kobj;
288 ret = kobject_uevent(&map->kobj, KOBJ_ADD);
289 if (ret)
290 goto err_map;
291 }
292
293 for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
294 port = &idev->info->port[pi];
295 if (port->size == 0)
296 break;
297 if (!portio_found) {
298 portio_found = 1;
299 idev->portio_dir = kobject_create_and_add("portio",
300 &idev->dev->kobj);
301 if (!idev->portio_dir)
302 goto err_portio;
303 }
304 portio = kzalloc(sizeof(*portio), GFP_KERNEL);
305 if (!portio)
306 goto err_portio_kobj;
307 kobject_init(&portio->kobj, &portio_attr_type);
308 portio->port = port;
309 port->portio = portio;
310 ret = kobject_add(&portio->kobj, idev->portio_dir,
311 "port%d", pi);
312 if (ret)
313 goto err_portio_kobj;
314 ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
315 if (ret)
316 goto err_portio;
317 }
318
319 return 0;
320
321 err_portio:
322 pi--;
323 err_portio_kobj:
324 for (; pi >= 0; pi--) {
325 port = &idev->info->port[pi];
326 portio = port->portio;
327 kobject_put(&portio->kobj);
328 }
329 kobject_put(idev->portio_dir);
330 err_map:
331 mi--;
332 err_map_kobj:
333 for (; mi >= 0; mi--) {
334 mem = &idev->info->mem[mi];
335 map = mem->map;
336 kobject_put(&map->kobj);
337 }
338 kobject_put(idev->map_dir);
339 dev_err(idev->dev, "error creating sysfs files (%d)\n", ret);
340 return ret;
341 }
342
uio_dev_del_attributes(struct uio_device * idev)343 static void uio_dev_del_attributes(struct uio_device *idev)
344 {
345 int i;
346 struct uio_mem *mem;
347 struct uio_port *port;
348
349 for (i = 0; i < MAX_UIO_MAPS; i++) {
350 mem = &idev->info->mem[i];
351 if (mem->size == 0)
352 break;
353 kobject_put(&mem->map->kobj);
354 }
355 kobject_put(idev->map_dir);
356
357 for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
358 port = &idev->info->port[i];
359 if (port->size == 0)
360 break;
361 kobject_put(&port->portio->kobj);
362 }
363 kobject_put(idev->portio_dir);
364 }
365
uio_get_minor(struct uio_device * idev)366 static int uio_get_minor(struct uio_device *idev)
367 {
368 int retval = -ENOMEM;
369
370 mutex_lock(&minor_lock);
371 retval = idr_alloc(&uio_idr, idev, 0, UIO_MAX_DEVICES, GFP_KERNEL);
372 if (retval >= 0) {
373 idev->minor = retval;
374 retval = 0;
375 } else if (retval == -ENOSPC) {
376 dev_err(idev->dev, "too many uio devices\n");
377 retval = -EINVAL;
378 }
379 mutex_unlock(&minor_lock);
380 return retval;
381 }
382
uio_free_minor(struct uio_device * idev)383 static void uio_free_minor(struct uio_device *idev)
384 {
385 mutex_lock(&minor_lock);
386 idr_remove(&uio_idr, idev->minor);
387 mutex_unlock(&minor_lock);
388 }
389
390 /**
391 * uio_event_notify - trigger an interrupt event
392 * @info: UIO device capabilities
393 */
uio_event_notify(struct uio_info * info)394 void uio_event_notify(struct uio_info *info)
395 {
396 struct uio_device *idev = info->uio_dev;
397
398 atomic_inc(&idev->event);
399 wake_up_interruptible(&idev->wait);
400 kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
401 }
402 EXPORT_SYMBOL_GPL(uio_event_notify);
403
404 /**
405 * uio_interrupt - hardware interrupt handler
406 * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
407 * @dev_id: Pointer to the devices uio_device structure
408 */
uio_interrupt(int irq,void * dev_id)409 static irqreturn_t uio_interrupt(int irq, void *dev_id)
410 {
411 struct uio_device *idev = (struct uio_device *)dev_id;
412 irqreturn_t ret = idev->info->handler(irq, idev->info);
413
414 if (ret == IRQ_HANDLED)
415 uio_event_notify(idev->info);
416
417 return ret;
418 }
419
420 struct uio_listener {
421 struct uio_device *dev;
422 s32 event_count;
423 };
424
uio_open(struct inode * inode,struct file * filep)425 static int uio_open(struct inode *inode, struct file *filep)
426 {
427 struct uio_device *idev;
428 struct uio_listener *listener;
429 int ret = 0;
430
431 mutex_lock(&minor_lock);
432 idev = idr_find(&uio_idr, iminor(inode));
433 mutex_unlock(&minor_lock);
434 if (!idev) {
435 ret = -ENODEV;
436 goto out;
437 }
438
439 if (!try_module_get(idev->owner)) {
440 ret = -ENODEV;
441 goto out;
442 }
443
444 listener = kmalloc(sizeof(*listener), GFP_KERNEL);
445 if (!listener) {
446 ret = -ENOMEM;
447 goto err_alloc_listener;
448 }
449
450 listener->dev = idev;
451 listener->event_count = atomic_read(&idev->event);
452 filep->private_data = listener;
453
454 if (idev->info->open) {
455 ret = idev->info->open(idev->info, inode);
456 if (ret)
457 goto err_infoopen;
458 }
459 return 0;
460
461 err_infoopen:
462 kfree(listener);
463
464 err_alloc_listener:
465 module_put(idev->owner);
466
467 out:
468 return ret;
469 }
470
uio_fasync(int fd,struct file * filep,int on)471 static int uio_fasync(int fd, struct file *filep, int on)
472 {
473 struct uio_listener *listener = filep->private_data;
474 struct uio_device *idev = listener->dev;
475
476 return fasync_helper(fd, filep, on, &idev->async_queue);
477 }
478
uio_release(struct inode * inode,struct file * filep)479 static int uio_release(struct inode *inode, struct file *filep)
480 {
481 int ret = 0;
482 struct uio_listener *listener = filep->private_data;
483 struct uio_device *idev = listener->dev;
484
485 if (idev->info->release)
486 ret = idev->info->release(idev->info, inode);
487
488 module_put(idev->owner);
489 kfree(listener);
490 return ret;
491 }
492
uio_poll(struct file * filep,poll_table * wait)493 static unsigned int uio_poll(struct file *filep, poll_table *wait)
494 {
495 struct uio_listener *listener = filep->private_data;
496 struct uio_device *idev = listener->dev;
497
498 if (!idev->info->irq)
499 return -EIO;
500
501 poll_wait(filep, &idev->wait, wait);
502 if (listener->event_count != atomic_read(&idev->event))
503 return POLLIN | POLLRDNORM;
504 return 0;
505 }
506
uio_read(struct file * filep,char __user * buf,size_t count,loff_t * ppos)507 static ssize_t uio_read(struct file *filep, char __user *buf,
508 size_t count, loff_t *ppos)
509 {
510 struct uio_listener *listener = filep->private_data;
511 struct uio_device *idev = listener->dev;
512 DECLARE_WAITQUEUE(wait, current);
513 ssize_t retval;
514 s32 event_count;
515
516 if (!idev->info->irq)
517 return -EIO;
518
519 if (count != sizeof(s32))
520 return -EINVAL;
521
522 add_wait_queue(&idev->wait, &wait);
523
524 do {
525 set_current_state(TASK_INTERRUPTIBLE);
526
527 event_count = atomic_read(&idev->event);
528 if (event_count != listener->event_count) {
529 __set_current_state(TASK_RUNNING);
530 if (copy_to_user(buf, &event_count, count))
531 retval = -EFAULT;
532 else {
533 listener->event_count = event_count;
534 retval = count;
535 }
536 break;
537 }
538
539 if (filep->f_flags & O_NONBLOCK) {
540 retval = -EAGAIN;
541 break;
542 }
543
544 if (signal_pending(current)) {
545 retval = -ERESTARTSYS;
546 break;
547 }
548 schedule();
549 } while (1);
550
551 __set_current_state(TASK_RUNNING);
552 remove_wait_queue(&idev->wait, &wait);
553
554 return retval;
555 }
556
uio_write(struct file * filep,const char __user * buf,size_t count,loff_t * ppos)557 static ssize_t uio_write(struct file *filep, const char __user *buf,
558 size_t count, loff_t *ppos)
559 {
560 struct uio_listener *listener = filep->private_data;
561 struct uio_device *idev = listener->dev;
562 ssize_t retval;
563 s32 irq_on;
564
565 if (!idev->info->irq)
566 return -EIO;
567
568 if (count != sizeof(s32))
569 return -EINVAL;
570
571 if (!idev->info->irqcontrol)
572 return -ENOSYS;
573
574 if (copy_from_user(&irq_on, buf, count))
575 return -EFAULT;
576
577 retval = idev->info->irqcontrol(idev->info, irq_on);
578
579 return retval ? retval : sizeof(s32);
580 }
581
uio_find_mem_index(struct vm_area_struct * vma)582 static int uio_find_mem_index(struct vm_area_struct *vma)
583 {
584 struct uio_device *idev = vma->vm_private_data;
585
586 if (vma->vm_pgoff < MAX_UIO_MAPS) {
587 if (idev->info->mem[vma->vm_pgoff].size == 0)
588 return -1;
589 return (int)vma->vm_pgoff;
590 }
591 return -1;
592 }
593
uio_vma_fault(struct vm_area_struct * vma,struct vm_fault * vmf)594 static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
595 {
596 struct uio_device *idev = vma->vm_private_data;
597 struct page *page;
598 unsigned long offset;
599 void *addr;
600
601 int mi = uio_find_mem_index(vma);
602 if (mi < 0)
603 return VM_FAULT_SIGBUS;
604
605 /*
606 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
607 * to use mem[N].
608 */
609 offset = (vmf->pgoff - mi) << PAGE_SHIFT;
610
611 addr = (void *)(unsigned long)idev->info->mem[mi].addr + offset;
612 if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
613 page = virt_to_page(addr);
614 else
615 page = vmalloc_to_page(addr);
616 get_page(page);
617 vmf->page = page;
618 return 0;
619 }
620
621 static const struct vm_operations_struct uio_logical_vm_ops = {
622 .fault = uio_vma_fault,
623 };
624
uio_mmap_logical(struct vm_area_struct * vma)625 static int uio_mmap_logical(struct vm_area_struct *vma)
626 {
627 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
628 vma->vm_ops = &uio_logical_vm_ops;
629 return 0;
630 }
631
632 static const struct vm_operations_struct uio_physical_vm_ops = {
633 #ifdef CONFIG_HAVE_IOREMAP_PROT
634 .access = generic_access_phys,
635 #endif
636 };
637
uio_mmap_physical(struct vm_area_struct * vma)638 static int uio_mmap_physical(struct vm_area_struct *vma)
639 {
640 struct uio_device *idev = vma->vm_private_data;
641 int mi = uio_find_mem_index(vma);
642 struct uio_mem *mem;
643 if (mi < 0)
644 return -EINVAL;
645 mem = idev->info->mem + mi;
646
647 if (mem->addr & ~PAGE_MASK)
648 return -ENODEV;
649 if (vma->vm_end - vma->vm_start > mem->size)
650 return -EINVAL;
651
652 vma->vm_ops = &uio_physical_vm_ops;
653 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
654
655 /*
656 * We cannot use the vm_iomap_memory() helper here,
657 * because vma->vm_pgoff is the map index we looked
658 * up above in uio_find_mem_index(), rather than an
659 * actual page offset into the mmap.
660 *
661 * So we just do the physical mmap without a page
662 * offset.
663 */
664 return remap_pfn_range(vma,
665 vma->vm_start,
666 mem->addr >> PAGE_SHIFT,
667 vma->vm_end - vma->vm_start,
668 vma->vm_page_prot);
669 }
670
uio_mmap(struct file * filep,struct vm_area_struct * vma)671 static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
672 {
673 struct uio_listener *listener = filep->private_data;
674 struct uio_device *idev = listener->dev;
675 int mi;
676 unsigned long requested_pages, actual_pages;
677 int ret = 0;
678
679 if (vma->vm_end < vma->vm_start)
680 return -EINVAL;
681
682 vma->vm_private_data = idev;
683
684 mi = uio_find_mem_index(vma);
685 if (mi < 0)
686 return -EINVAL;
687
688 requested_pages = vma_pages(vma);
689 actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
690 + idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
691 if (requested_pages > actual_pages)
692 return -EINVAL;
693
694 if (idev->info->mmap) {
695 ret = idev->info->mmap(idev->info, vma);
696 return ret;
697 }
698
699 switch (idev->info->mem[mi].memtype) {
700 case UIO_MEM_PHYS:
701 return uio_mmap_physical(vma);
702 case UIO_MEM_LOGICAL:
703 case UIO_MEM_VIRTUAL:
704 return uio_mmap_logical(vma);
705 default:
706 return -EINVAL;
707 }
708 }
709
710 static const struct file_operations uio_fops = {
711 .owner = THIS_MODULE,
712 .open = uio_open,
713 .release = uio_release,
714 .read = uio_read,
715 .write = uio_write,
716 .mmap = uio_mmap,
717 .poll = uio_poll,
718 .fasync = uio_fasync,
719 .llseek = noop_llseek,
720 };
721
uio_major_init(void)722 static int uio_major_init(void)
723 {
724 static const char name[] = "uio";
725 struct cdev *cdev = NULL;
726 dev_t uio_dev = 0;
727 int result;
728
729 result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name);
730 if (result)
731 goto out;
732
733 result = -ENOMEM;
734 cdev = cdev_alloc();
735 if (!cdev)
736 goto out_unregister;
737
738 cdev->owner = THIS_MODULE;
739 cdev->ops = &uio_fops;
740 kobject_set_name(&cdev->kobj, "%s", name);
741
742 result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES);
743 if (result)
744 goto out_put;
745
746 uio_major = MAJOR(uio_dev);
747 uio_cdev = cdev;
748 return 0;
749 out_put:
750 kobject_put(&cdev->kobj);
751 out_unregister:
752 unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
753 out:
754 return result;
755 }
756
uio_major_cleanup(void)757 static void uio_major_cleanup(void)
758 {
759 unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
760 cdev_del(uio_cdev);
761 }
762
init_uio_class(void)763 static int init_uio_class(void)
764 {
765 int ret;
766
767 /* This is the first time in here, set everything up properly */
768 ret = uio_major_init();
769 if (ret)
770 goto exit;
771
772 ret = class_register(&uio_class);
773 if (ret) {
774 printk(KERN_ERR "class_register failed for uio\n");
775 goto err_class_register;
776 }
777
778 uio_class_registered = true;
779
780 return 0;
781
782 err_class_register:
783 uio_major_cleanup();
784 exit:
785 return ret;
786 }
787
release_uio_class(void)788 static void release_uio_class(void)
789 {
790 uio_class_registered = false;
791 class_unregister(&uio_class);
792 uio_major_cleanup();
793 }
794
795 /**
796 * uio_register_device - register a new userspace IO device
797 * @owner: module that creates the new device
798 * @parent: parent device
799 * @info: UIO device capabilities
800 *
801 * returns zero on success or a negative error code.
802 */
__uio_register_device(struct module * owner,struct device * parent,struct uio_info * info)803 int __uio_register_device(struct module *owner,
804 struct device *parent,
805 struct uio_info *info)
806 {
807 struct uio_device *idev;
808 int ret = 0;
809
810 if (!uio_class_registered)
811 return -EPROBE_DEFER;
812
813 if (!parent || !info || !info->name || !info->version)
814 return -EINVAL;
815
816 info->uio_dev = NULL;
817
818 idev = devm_kzalloc(parent, sizeof(*idev), GFP_KERNEL);
819 if (!idev) {
820 return -ENOMEM;
821 }
822
823 idev->owner = owner;
824 idev->info = info;
825 init_waitqueue_head(&idev->wait);
826 atomic_set(&idev->event, 0);
827
828 ret = uio_get_minor(idev);
829 if (ret)
830 return ret;
831
832 idev->dev = device_create(&uio_class, parent,
833 MKDEV(uio_major, idev->minor), idev,
834 "uio%d", idev->minor);
835 if (IS_ERR(idev->dev)) {
836 printk(KERN_ERR "UIO: device register failed\n");
837 ret = PTR_ERR(idev->dev);
838 goto err_device_create;
839 }
840
841 ret = uio_dev_add_attributes(idev);
842 if (ret)
843 goto err_uio_dev_add_attributes;
844
845 info->uio_dev = idev;
846
847 if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) {
848 /*
849 * Note that we deliberately don't use devm_request_irq
850 * here. The parent module can unregister the UIO device
851 * and call pci_disable_msi, which requires that this
852 * irq has been freed. However, the device may have open
853 * FDs at the time of unregister and therefore may not be
854 * freed until they are released.
855 */
856 ret = request_irq(info->irq, uio_interrupt,
857 info->irq_flags, info->name, idev);
858 if (ret) {
859 info->uio_dev = NULL;
860 goto err_request_irq;
861 }
862 }
863
864 return 0;
865
866 err_request_irq:
867 uio_dev_del_attributes(idev);
868 err_uio_dev_add_attributes:
869 device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
870 err_device_create:
871 uio_free_minor(idev);
872 return ret;
873 }
874 EXPORT_SYMBOL_GPL(__uio_register_device);
875
876 /**
877 * uio_unregister_device - unregister a industrial IO device
878 * @info: UIO device capabilities
879 *
880 */
uio_unregister_device(struct uio_info * info)881 void uio_unregister_device(struct uio_info *info)
882 {
883 struct uio_device *idev;
884
885 if (!info || !info->uio_dev)
886 return;
887
888 idev = info->uio_dev;
889
890 uio_free_minor(idev);
891
892 uio_dev_del_attributes(idev);
893
894 if (info->irq && info->irq != UIO_IRQ_CUSTOM)
895 free_irq(info->irq, idev);
896
897 device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
898
899 return;
900 }
901 EXPORT_SYMBOL_GPL(uio_unregister_device);
902
uio_init(void)903 static int __init uio_init(void)
904 {
905 return init_uio_class();
906 }
907
uio_exit(void)908 static void __exit uio_exit(void)
909 {
910 release_uio_class();
911 idr_destroy(&uio_idr);
912 }
913
914 module_init(uio_init)
915 module_exit(uio_exit)
916 MODULE_LICENSE("GPL v2");
917