Root/drivers/uio/uio.c

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

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