[go: nahoru, domu]
uio.c revision 81e7c6a636c81d9eeaeaa732bfbace44535fab00 
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@linutronix.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/mm.h>
21#include <linux/idr.h>
22#include <linux/string.h>
23#include <linux/kobject.h>
24#include <linux/uio_driver.h>
25
26#define UIO_MAX_DEVICES 255
27
28struct uio_device {
29	struct module		*owner;
30	struct device		*dev;
31	int			minor;
32	atomic_t		event;
33	struct fasync_struct	*async_queue;
34	wait_queue_head_t	wait;
35	int			vma_count;
36	struct uio_info		*info;
37	struct kobject		*map_dir;
38};
39
40static int uio_major;
41static DEFINE_IDR(uio_idr);
42static struct file_operations uio_fops;
43
44/* UIO class infrastructure */
45static struct uio_class {
46	struct kref kref;
47	struct class *class;
48} *uio_class;
49
50/*
51 * attributes
52 */
53
54struct uio_map {
55	struct kobject kobj;
56	struct uio_mem *mem;
57};
58#define to_map(map) container_of(map, struct uio_map, kobj)
59
60
61static ssize_t map_attr_show(struct kobject *kobj, struct kobj_attribute *attr,
62			     char *buf)
63{
64	struct uio_map *map = to_map(kobj);
65	struct uio_mem *mem = map->mem;
66
67	if (strncmp(attr->attr.name, "addr", 4) == 0)
68		return sprintf(buf, "0x%lx\n", mem->addr);
69
70	if (strncmp(attr->attr.name, "size", 4) == 0)
71		return sprintf(buf, "0x%lx\n", mem->size);
72
73	return -ENODEV;
74}
75
76static struct kobj_attribute attr_attribute =
77	__ATTR(addr, S_IRUGO, map_attr_show, NULL);
78static struct kobj_attribute size_attribute =
79	__ATTR(size, S_IRUGO, map_attr_show, NULL);
80
81static struct attribute *attrs[] = {
82	&attr_attribute.attr,
83	&size_attribute.attr,
84	NULL,	/* need to NULL terminate the list of attributes */
85};
86
87static void map_release(struct kobject *kobj)
88{
89	struct uio_map *map = to_map(kobj);
90	kfree(map);
91}
92
93static struct kobj_type map_attr_type = {
94	.release	= map_release,
95	.default_attrs	= attrs,
96};
97
98static ssize_t show_name(struct device *dev,
99			 struct device_attribute *attr, char *buf)
100{
101	struct uio_device *idev = dev_get_drvdata(dev);
102	if (idev)
103		return sprintf(buf, "%s\n", idev->info->name);
104	else
105		return -ENODEV;
106}
107static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
108
109static ssize_t show_version(struct device *dev,
110			    struct device_attribute *attr, char *buf)
111{
112	struct uio_device *idev = dev_get_drvdata(dev);
113	if (idev)
114		return sprintf(buf, "%s\n", idev->info->version);
115	else
116		return -ENODEV;
117}
118static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);
119
120static ssize_t show_event(struct device *dev,
121			  struct device_attribute *attr, char *buf)
122{
123	struct uio_device *idev = dev_get_drvdata(dev);
124	if (idev)
125		return sprintf(buf, "%u\n",
126				(unsigned int)atomic_read(&idev->event));
127	else
128		return -ENODEV;
129}
130static DEVICE_ATTR(event, S_IRUGO, show_event, NULL);
131
132static struct attribute *uio_attrs[] = {
133	&dev_attr_name.attr,
134	&dev_attr_version.attr,
135	&dev_attr_event.attr,
136	NULL,
137};
138
139static struct attribute_group uio_attr_grp = {
140	.attrs = uio_attrs,
141};
142
143/*
144 * device functions
145 */
146static int uio_dev_add_attributes(struct uio_device *idev)
147{
148	int ret;
149	int mi;
150	int map_found = 0;
151	struct uio_mem *mem;
152	struct uio_map *map;
153
154	ret = sysfs_create_group(&idev->dev->kobj, &uio_attr_grp);
155	if (ret)
156		goto err_group;
157
158	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
159		mem = &idev->info->mem[mi];
160		if (mem->size == 0)
161			break;
162		if (!map_found) {
163			map_found = 1;
164			idev->map_dir = kobject_create_and_add("maps",
165							&idev->dev->kobj);
166			if (!idev->map_dir)
167				goto err;
168		}
169		map = kzalloc(sizeof(*map), GFP_KERNEL);
170		if (!map)
171			goto err;
172		kobject_init_ng(&map->kobj, &map_attr_type);
173		map->mem = mem;
174		mem->map = map;
175		ret = kobject_add_ng(&map->kobj, idev->map_dir, "map%d", mi);
176		if (ret)
177			goto err;
178		ret = kobject_uevent(&map->kobj, KOBJ_ADD);
179		if (ret)
180			goto err;
181	}
182
183	return 0;
184
185err:
186	for (mi--; mi>=0; mi--) {
187		mem = &idev->info->mem[mi];
188		map = mem->map;
189		kobject_unregister(&map->kobj);
190	}
191	kobject_unregister(idev->map_dir);
192	sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
193err_group:
194	dev_err(idev->dev, "error creating sysfs files (%d)\n", ret);
195	return ret;
196}
197
198static void uio_dev_del_attributes(struct uio_device *idev)
199{
200	int mi;
201	struct uio_mem *mem;
202	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
203		mem = &idev->info->mem[mi];
204		if (mem->size == 0)
205			break;
206		kobject_unregister(&mem->map->kobj);
207	}
208	kobject_unregister(idev->map_dir);
209	sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
210}
211
212static int uio_get_minor(struct uio_device *idev)
213{
214	static DEFINE_MUTEX(minor_lock);
215	int retval = -ENOMEM;
216	int id;
217
218	mutex_lock(&minor_lock);
219	if (idr_pre_get(&uio_idr, GFP_KERNEL) == 0)
220		goto exit;
221
222	retval = idr_get_new(&uio_idr, idev, &id);
223	if (retval < 0) {
224		if (retval == -EAGAIN)
225			retval = -ENOMEM;
226		goto exit;
227	}
228	idev->minor = id & MAX_ID_MASK;
229exit:
230	mutex_unlock(&minor_lock);
231	return retval;
232}
233
234static void uio_free_minor(struct uio_device *idev)
235{
236	idr_remove(&uio_idr, idev->minor);
237}
238
239/**
240 * uio_event_notify - trigger an interrupt event
241 * @info: UIO device capabilities
242 */
243void uio_event_notify(struct uio_info *info)
244{
245	struct uio_device *idev = info->uio_dev;
246
247	atomic_inc(&idev->event);
248	wake_up_interruptible(&idev->wait);
249	kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
250}
251EXPORT_SYMBOL_GPL(uio_event_notify);
252
253/**
254 * uio_interrupt - hardware interrupt handler
255 * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
256 * @dev_id: Pointer to the devices uio_device structure
257 */
258static irqreturn_t uio_interrupt(int irq, void *dev_id)
259{
260	struct uio_device *idev = (struct uio_device *)dev_id;
261	irqreturn_t ret = idev->info->handler(irq, idev->info);
262
263	if (ret == IRQ_HANDLED)
264		uio_event_notify(idev->info);
265
266	return ret;
267}
268
269struct uio_listener {
270	struct uio_device *dev;
271	s32 event_count;
272};
273
274static int uio_open(struct inode *inode, struct file *filep)
275{
276	struct uio_device *idev;
277	struct uio_listener *listener;
278	int ret = 0;
279
280	idev = idr_find(&uio_idr, iminor(inode));
281	if (!idev)
282		return -ENODEV;
283
284	listener = kmalloc(sizeof(*listener), GFP_KERNEL);
285	if (!listener)
286		return -ENOMEM;
287
288	listener->dev = idev;
289	listener->event_count = atomic_read(&idev->event);
290	filep->private_data = listener;
291
292	if (idev->info->open) {
293		if (!try_module_get(idev->owner))
294			return -ENODEV;
295		ret = idev->info->open(idev->info, inode);
296		module_put(idev->owner);
297	}
298
299	if (ret)
300		kfree(listener);
301
302	return ret;
303}
304
305static int uio_fasync(int fd, struct file *filep, int on)
306{
307	struct uio_listener *listener = filep->private_data;
308	struct uio_device *idev = listener->dev;
309
310	return fasync_helper(fd, filep, on, &idev->async_queue);
311}
312
313static int uio_release(struct inode *inode, struct file *filep)
314{
315	int ret = 0;
316	struct uio_listener *listener = filep->private_data;
317	struct uio_device *idev = listener->dev;
318
319	if (idev->info->release) {
320		if (!try_module_get(idev->owner))
321			return -ENODEV;
322		ret = idev->info->release(idev->info, inode);
323		module_put(idev->owner);
324	}
325	if (filep->f_flags & FASYNC)
326		ret = uio_fasync(-1, filep, 0);
327	kfree(listener);
328	return ret;
329}
330
331static unsigned int uio_poll(struct file *filep, poll_table *wait)
332{
333	struct uio_listener *listener = filep->private_data;
334	struct uio_device *idev = listener->dev;
335
336	if (idev->info->irq == UIO_IRQ_NONE)
337		return -EIO;
338
339	poll_wait(filep, &idev->wait, wait);
340	if (listener->event_count != atomic_read(&idev->event))
341		return POLLIN | POLLRDNORM;
342	return 0;
343}
344
345static ssize_t uio_read(struct file *filep, char __user *buf,
346			size_t count, loff_t *ppos)
347{
348	struct uio_listener *listener = filep->private_data;
349	struct uio_device *idev = listener->dev;
350	DECLARE_WAITQUEUE(wait, current);
351	ssize_t retval;
352	s32 event_count;
353
354	if (idev->info->irq == UIO_IRQ_NONE)
355		return -EIO;
356
357	if (count != sizeof(s32))
358		return -EINVAL;
359
360	add_wait_queue(&idev->wait, &wait);
361
362	do {
363		set_current_state(TASK_INTERRUPTIBLE);
364
365		event_count = atomic_read(&idev->event);
366		if (event_count != listener->event_count) {
367			if (copy_to_user(buf, &event_count, count))
368				retval = -EFAULT;
369			else {
370				listener->event_count = event_count;
371				retval = count;
372			}
373			break;
374		}
375
376		if (filep->f_flags & O_NONBLOCK) {
377			retval = -EAGAIN;
378			break;
379		}
380
381		if (signal_pending(current)) {
382			retval = -ERESTARTSYS;
383			break;
384		}
385		schedule();
386	} while (1);
387
388	__set_current_state(TASK_RUNNING);
389	remove_wait_queue(&idev->wait, &wait);
390
391	return retval;
392}
393
394static int uio_find_mem_index(struct vm_area_struct *vma)
395{
396	int mi;
397	struct uio_device *idev = vma->vm_private_data;
398
399	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
400		if (idev->info->mem[mi].size == 0)
401			return -1;
402		if (vma->vm_pgoff == mi)
403			return mi;
404	}
405	return -1;
406}
407
408static void uio_vma_open(struct vm_area_struct *vma)
409{
410	struct uio_device *idev = vma->vm_private_data;
411	idev->vma_count++;
412}
413
414static void uio_vma_close(struct vm_area_struct *vma)
415{
416	struct uio_device *idev = vma->vm_private_data;
417	idev->vma_count--;
418}
419
420static struct page *uio_vma_nopage(struct vm_area_struct *vma,
421				   unsigned long address, int *type)
422{
423	struct uio_device *idev = vma->vm_private_data;
424	struct page* page = NOPAGE_SIGBUS;
425
426	int mi = uio_find_mem_index(vma);
427	if (mi < 0)
428		return page;
429
430	if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
431		page = virt_to_page(idev->info->mem[mi].addr);
432	else
433		page = vmalloc_to_page((void*)idev->info->mem[mi].addr);
434	get_page(page);
435	if (type)
436		*type = VM_FAULT_MINOR;
437	return page;
438}
439
440static struct vm_operations_struct uio_vm_ops = {
441	.open = uio_vma_open,
442	.close = uio_vma_close,
443	.nopage = uio_vma_nopage,
444};
445
446static int uio_mmap_physical(struct vm_area_struct *vma)
447{
448	struct uio_device *idev = vma->vm_private_data;
449	int mi = uio_find_mem_index(vma);
450	if (mi < 0)
451		return -EINVAL;
452
453	vma->vm_flags |= VM_IO | VM_RESERVED;
454
455	return remap_pfn_range(vma,
456			       vma->vm_start,
457			       idev->info->mem[mi].addr >> PAGE_SHIFT,
458			       vma->vm_end - vma->vm_start,
459			       vma->vm_page_prot);
460}
461
462static int uio_mmap_logical(struct vm_area_struct *vma)
463{
464	vma->vm_flags |= VM_RESERVED;
465	vma->vm_ops = &uio_vm_ops;
466	uio_vma_open(vma);
467	return 0;
468}
469
470static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
471{
472	struct uio_listener *listener = filep->private_data;
473	struct uio_device *idev = listener->dev;
474	int mi;
475	unsigned long requested_pages, actual_pages;
476	int ret = 0;
477
478	if (vma->vm_end < vma->vm_start)
479		return -EINVAL;
480
481	vma->vm_private_data = idev;
482
483	mi = uio_find_mem_index(vma);
484	if (mi < 0)
485		return -EINVAL;
486
487	requested_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
488	actual_pages = (idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
489	if (requested_pages > actual_pages)
490		return -EINVAL;
491
492	if (idev->info->mmap) {
493		if (!try_module_get(idev->owner))
494			return -ENODEV;
495		ret = idev->info->mmap(idev->info, vma);
496		module_put(idev->owner);
497		return ret;
498	}
499
500	switch (idev->info->mem[mi].memtype) {
501		case UIO_MEM_PHYS:
502			return uio_mmap_physical(vma);
503		case UIO_MEM_LOGICAL:
504		case UIO_MEM_VIRTUAL:
505			return uio_mmap_logical(vma);
506		default:
507			return -EINVAL;
508	}
509}
510
511static struct file_operations uio_fops = {
512	.owner		= THIS_MODULE,
513	.open		= uio_open,
514	.release	= uio_release,
515	.read		= uio_read,
516	.mmap		= uio_mmap,
517	.poll		= uio_poll,
518	.fasync		= uio_fasync,
519};
520
521static int uio_major_init(void)
522{
523	uio_major = register_chrdev(0, "uio", &uio_fops);
524	if (uio_major < 0)
525		return uio_major;
526	return 0;
527}
528
529static void uio_major_cleanup(void)
530{
531	unregister_chrdev(uio_major, "uio");
532}
533
534static int init_uio_class(void)
535{
536	int ret = 0;
537
538	if (uio_class != NULL) {
539		kref_get(&uio_class->kref);
540		goto exit;
541	}
542
543	/* This is the first time in here, set everything up properly */
544	ret = uio_major_init();
545	if (ret)
546		goto exit;
547
548	uio_class = kzalloc(sizeof(*uio_class), GFP_KERNEL);
549	if (!uio_class) {
550		ret = -ENOMEM;
551		goto err_kzalloc;
552	}
553
554	kref_init(&uio_class->kref);
555	uio_class->class = class_create(THIS_MODULE, "uio");
556	if (IS_ERR(uio_class->class)) {
557		ret = IS_ERR(uio_class->class);
558		printk(KERN_ERR "class_create failed for uio\n");
559		goto err_class_create;
560	}
561	return 0;
562
563err_class_create:
564	kfree(uio_class);
565	uio_class = NULL;
566err_kzalloc:
567	uio_major_cleanup();
568exit:
569	return ret;
570}
571
572static void release_uio_class(struct kref *kref)
573{
574	/* Ok, we cheat as we know we only have one uio_class */
575	class_destroy(uio_class->class);
576	kfree(uio_class);
577	uio_major_cleanup();
578	uio_class = NULL;
579}
580
581static void uio_class_destroy(void)
582{
583	if (uio_class)
584		kref_put(&uio_class->kref, release_uio_class);
585}
586
587/**
588 * uio_register_device - register a new userspace IO device
589 * @owner:	module that creates the new device
590 * @parent:	parent device
591 * @info:	UIO device capabilities
592 *
593 * returns zero on success or a negative error code.
594 */
595int __uio_register_device(struct module *owner,
596			  struct device *parent,
597			  struct uio_info *info)
598{
599	struct uio_device *idev;
600	int ret = 0;
601
602	if (!parent || !info || !info->name || !info->version)
603		return -EINVAL;
604
605	info->uio_dev = NULL;
606
607	ret = init_uio_class();
608	if (ret)
609		return ret;
610
611	idev = kzalloc(sizeof(*idev), GFP_KERNEL);
612	if (!idev) {
613		ret = -ENOMEM;
614		goto err_kzalloc;
615	}
616
617	idev->owner = owner;
618	idev->info = info;
619	init_waitqueue_head(&idev->wait);
620	atomic_set(&idev->event, 0);
621
622	ret = uio_get_minor(idev);
623	if (ret)
624		goto err_get_minor;
625
626	idev->dev = device_create(uio_class->class, parent,
627				  MKDEV(uio_major, idev->minor),
628				  "uio%d", idev->minor);
629	if (IS_ERR(idev->dev)) {
630		printk(KERN_ERR "UIO: device register failed\n");
631		ret = PTR_ERR(idev->dev);
632		goto err_device_create;
633	}
634	dev_set_drvdata(idev->dev, idev);
635
636	ret = uio_dev_add_attributes(idev);
637	if (ret)
638		goto err_uio_dev_add_attributes;
639
640	info->uio_dev = idev;
641
642	if (idev->info->irq >= 0) {
643		ret = request_irq(idev->info->irq, uio_interrupt,
644				  idev->info->irq_flags, idev->info->name, idev);
645		if (ret)
646			goto err_request_irq;
647	}
648
649	return 0;
650
651err_request_irq:
652	uio_dev_del_attributes(idev);
653err_uio_dev_add_attributes:
654	device_destroy(uio_class->class, MKDEV(uio_major, idev->minor));
655err_device_create:
656	uio_free_minor(idev);
657err_get_minor:
658	kfree(idev);
659err_kzalloc:
660	uio_class_destroy();
661	return ret;
662}
663EXPORT_SYMBOL_GPL(__uio_register_device);
664
665/**
666 * uio_unregister_device - unregister a industrial IO device
667 * @info:	UIO device capabilities
668 *
669 */
670void uio_unregister_device(struct uio_info *info)
671{
672	struct uio_device *idev;
673
674	if (!info || !info->uio_dev)
675		return;
676
677	idev = info->uio_dev;
678
679	uio_free_minor(idev);
680
681	if (info->irq >= 0)
682		free_irq(info->irq, idev);
683
684	uio_dev_del_attributes(idev);
685
686	dev_set_drvdata(idev->dev, NULL);
687	device_destroy(uio_class->class, MKDEV(uio_major, idev->minor));
688	kfree(idev);
689	uio_class_destroy();
690
691	return;
692}
693EXPORT_SYMBOL_GPL(uio_unregister_device);
694
695static int __init uio_init(void)
696{
697	return 0;
698}
699
700static void __exit uio_exit(void)
701{
702}
703
704module_init(uio_init)
705module_exit(uio_exit)
706MODULE_LICENSE("GPL v2");
707