drivers/uio/uio.c - kernel/msm - Gitiles

 /*
  * drivers/uio/uio.c
  *
  * Copyright(C) 2005, Benedikt Spranger <b.spranger@linutronix.de>
  * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
  * Copyright(C) 2006, Hans J. Koch <hjk@linutronix.de>
  * Copyright(C) 2006, Greg Kroah-Hartman <greg@kroah.com>
  *
  * Userspace IO
  *
  * Base Functions
  *
  * Licensed under the GPLv2 only.
  */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/poll.h>
 #include <linux/device.h>
 #include <linux/mm.h>
 #include <linux/idr.h>
 #include <linux/string.h>
 #include <linux/kobject.h>
 #include <linux/uio_driver.h>

 #define UIO_MAX_DEVICES 255

 struct uio_device {
 	struct module		*owner;
 	struct device		*dev;
 	int			minor;
 	atomic_t		event;
 	struct fasync_struct	*async_queue;
 	wait_queue_head_t	wait;
 	int			vma_count;
 	struct uio_info		*info;
 	struct kobject		*map_dir;
 };

 static int uio_major;
 static DEFINE_IDR(uio_idr);
 static const struct file_operations uio_fops;

 /* UIO class infrastructure */
 static struct uio_class {
 	struct kref kref;
 	struct class *class;
 } *uio_class;

 /*
  * attributes
  */

 struct uio_map {
 	struct kobject kobj;
 	struct uio_mem *mem;
 };
 #define to_map(map) container_of(map, struct uio_map, kobj)


 static ssize_t map_attr_show(struct kobject *kobj, struct kobj_attribute *attr,
 			     char *buf)
 {
 	struct uio_map *map = to_map(kobj);
 	struct uio_mem *mem = map->mem;

 	if (strncmp(attr->attr.name, "addr", 4) == 0)
 		return sprintf(buf, "0x%lx\n", mem->addr);

 	if (strncmp(attr->attr.name, "size", 4) == 0)
 		return sprintf(buf, "0x%lx\n", mem->size);

 	return -ENODEV;
 }

 static struct kobj_attribute attr_attribute =
 	__ATTR(addr, S_IRUGO, map_attr_show, NULL);
 static struct kobj_attribute size_attribute =
 	__ATTR(size, S_IRUGO, map_attr_show, NULL);

 static struct attribute *attrs[] = {
 	&attr_attribute.attr,
 	&size_attribute.attr,
 	NULL,	/* need to NULL terminate the list of attributes */
 };

 static void map_release(struct kobject *kobj)
 {
 	struct uio_map *map = to_map(kobj);
 	kfree(map);
 }

 static struct kobj_type map_attr_type = {
 	.release	= map_release,
 	.default_attrs	= attrs,
 };

 static ssize_t show_name(struct device *dev,
 			 struct device_attribute *attr, char *buf)
 {
 	struct uio_device *idev = dev_get_drvdata(dev);
 	if (idev)
 		return sprintf(buf, "%s\n", idev->info->name);
 	else
 		return -ENODEV;
 }
 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

 static ssize_t show_version(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {
 	struct uio_device *idev = dev_get_drvdata(dev);
 	if (idev)
 		return sprintf(buf, "%s\n", idev->info->version);
 	else
 		return -ENODEV;
 }
 static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);

 static ssize_t show_event(struct device *dev,
 			  struct device_attribute *attr, char *buf)
 {
 	struct uio_device *idev = dev_get_drvdata(dev);
 	if (idev)
 		return sprintf(buf, "%u\n",
 				(unsigned int)atomic_read(&idev->event));
 	else
 		return -ENODEV;
 }
 static DEVICE_ATTR(event, S_IRUGO, show_event, NULL);

 static struct attribute *uio_attrs[] = {
 	&dev_attr_name.attr,
 	&dev_attr_version.attr,
 	&dev_attr_event.attr,
 	NULL,
 };

 static struct attribute_group uio_attr_grp = {
 	.attrs = uio_attrs,
 };

 /*
  * device functions
  */
 static int uio_dev_add_attributes(struct uio_device *idev)
 {
 	int ret;
 	int mi;
 	int map_found = 0;
 	struct uio_mem *mem;
 	struct uio_map *map;

 	ret = sysfs_create_group(&idev->dev->kobj, &uio_attr_grp);
 	if (ret)
 		goto err_group;

 	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
 		mem = &idev->info->mem[mi];
 		if (mem->size == 0)
 			break;
 		if (!map_found) {
 			map_found = 1;
 			idev->map_dir = kobject_create_and_add("maps",
 							&idev->dev->kobj);
 			if (!idev->map_dir)
 				goto err;
 		}
 		map = kzalloc(sizeof(*map), GFP_KERNEL);
 		if (!map)
 			goto err;
 		kobject_init(&map->kobj, &map_attr_type);
 		map->mem = mem;
 		mem->map = map;
 		ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
 		if (ret)
 			goto err;
 		ret = kobject_uevent(&map->kobj, KOBJ_ADD);
 		if (ret)
 			goto err;
 	}

 	return 0;

 err:
 	for (mi--; mi>=0; mi--) {
 		mem = &idev->info->mem[mi];
 		map = mem->map;
 		kobject_put(&map->kobj);
 	}
 	kobject_put(idev->map_dir);
 	sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
 err_group:
 	dev_err(idev->dev, "error creating sysfs files (%d)\n", ret);
 	return ret;
 }

 static void uio_dev_del_attributes(struct uio_device *idev)
 {
 	int mi;
 	struct uio_mem *mem;
 	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
 		mem = &idev->info->mem[mi];
 		if (mem->size == 0)
 			break;
 		kobject_put(&mem->map->kobj);
 	}
 	kobject_put(idev->map_dir);
 	sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
 }

 static int uio_get_minor(struct uio_device *idev)
 {
 	static DEFINE_MUTEX(minor_lock);
 	int retval = -ENOMEM;
 	int id;

 	mutex_lock(&minor_lock);
 	if (idr_pre_get(&uio_idr, GFP_KERNEL) == 0)
 		goto exit;

 	retval = idr_get_new(&uio_idr, idev, &id);
 	if (retval < 0) {
 		if (retval == -EAGAIN)
 			retval = -ENOMEM;
 		goto exit;
 	}
 	idev->minor = id & MAX_ID_MASK;
 exit:
 	mutex_unlock(&minor_lock);
 	return retval;
 }

 static void uio_free_minor(struct uio_device *idev)
 {
 	idr_remove(&uio_idr, idev->minor);
 }

 /**
  * uio_event_notify - trigger an interrupt event
  * @info: UIO device capabilities
  */
 void uio_event_notify(struct uio_info *info)
 {
 	struct uio_device *idev = info->uio_dev;

 	atomic_inc(&idev->event);
 	wake_up_interruptible(&idev->wait);
 	kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
 }
 EXPORT_SYMBOL_GPL(uio_event_notify);

 /**
  * uio_interrupt - hardware interrupt handler
  * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
  * @dev_id: Pointer to the devices uio_device structure
  */
 static irqreturn_t uio_interrupt(int irq, void *dev_id)
 {
 	struct uio_device *idev = (struct uio_device *)dev_id;
 	irqreturn_t ret = idev->info->handler(irq, idev->info);

 	if (ret == IRQ_HANDLED)
 		uio_event_notify(idev->info);

 	return ret;
 }

 struct uio_listener {
 	struct uio_device *dev;
 	s32 event_count;
 };

 static int uio_open(struct inode *inode, struct file *filep)
 {
 	struct uio_device *idev;
 	struct uio_listener *listener;
 	int ret = 0;

 	idev = idr_find(&uio_idr, iminor(inode));
 	if (!idev)
 		return -ENODEV;

 	listener = kmalloc(sizeof(*listener), GFP_KERNEL);
 	if (!listener)
 		return -ENOMEM;

 	listener->dev = idev;
 	listener->event_count = atomic_read(&idev->event);
 	filep->private_data = listener;

 	if (idev->info->open) {
 		if (!try_module_get(idev->owner))
 			return -ENODEV;
 		ret = idev->info->open(idev->info, inode);
 		module_put(idev->owner);
 	}

 	if (ret)
 		kfree(listener);

 	return ret;
 }

 static int uio_fasync(int fd, struct file *filep, int on)
 {
 	struct uio_listener *listener = filep->private_data;
 	struct uio_device *idev = listener->dev;

 	return fasync_helper(fd, filep, on, &idev->async_queue);
 }

 static int uio_release(struct inode *inode, struct file *filep)
 {
 	int ret = 0;
 	struct uio_listener *listener = filep->private_data;
 	struct uio_device *idev = listener->dev;

 	if (idev->info->release) {
 		if (!try_module_get(idev->owner))
 			return -ENODEV;
 		ret = idev->info->release(idev->info, inode);
 		module_put(idev->owner);
 	}
 	if (filep->f_flags & FASYNC)
 		ret = uio_fasync(-1, filep, 0);
 	kfree(listener);
 	return ret;
 }

 static unsigned int uio_poll(struct file *filep, poll_table *wait)
 {
 	struct uio_listener *listener = filep->private_data;
 	struct uio_device *idev = listener->dev;

 	if (idev->info->irq == UIO_IRQ_NONE)
 		return -EIO;

 	poll_wait(filep, &idev->wait, wait);
 	if (listener->event_count != atomic_read(&idev->event))
 		return POLLIN | POLLRDNORM;
 	return 0;
 }

 static ssize_t uio_read(struct file *filep, char __user *buf,
 			size_t count, loff_t *ppos)
 {
 	struct uio_listener *listener = filep->private_data;
 	struct uio_device *idev = listener->dev;
 	DECLARE_WAITQUEUE(wait, current);
 	ssize_t retval;
 	s32 event_count;

 	if (idev->info->irq == UIO_IRQ_NONE)
 		return -EIO;

 	if (count != sizeof(s32))
 		return -EINVAL;

 	add_wait_queue(&idev->wait, &wait);

 	do {
 		set_current_state(TASK_INTERRUPTIBLE);

 		event_count = atomic_read(&idev->event);
 		if (event_count != listener->event_count) {
 			if (copy_to_user(buf, &event_count, count))
 				retval = -EFAULT;
 			else {
 				listener->event_count = event_count;
 				retval = count;
 			}
 			break;
 		}

 		if (filep->f_flags & O_NONBLOCK) {
 			retval = -EAGAIN;
 			break;
 		}

 		if (signal_pending(current)) {
 			retval = -ERESTARTSYS;
 			break;
 		}
 		schedule();
 	} while (1);

 	__set_current_state(TASK_RUNNING);
 	remove_wait_queue(&idev->wait, &wait);

 	return retval;
 }

 static int uio_find_mem_index(struct vm_area_struct *vma)
 {
 	int mi;
 	struct uio_device *idev = vma->vm_private_data;

 	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
 		if (idev->info->mem[mi].size == 0)
 			return -1;
 		if (vma->vm_pgoff == mi)
 			return mi;
 	}
 	return -1;
 }

 static void uio_vma_open(struct vm_area_struct *vma)
 {
 	struct uio_device *idev = vma->vm_private_data;
 	idev->vma_count++;
 }

 static void uio_vma_close(struct vm_area_struct *vma)
 {
 	struct uio_device *idev = vma->vm_private_data;
 	idev->vma_count--;
 }

 static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	struct uio_device *idev = vma->vm_private_data;
 	struct page *page;

 	int mi = uio_find_mem_index(vma);
 	if (mi < 0)
 		return VM_FAULT_SIGBUS;

 	if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
 		page = virt_to_page(idev->info->mem[mi].addr);
 	else
 		page = vmalloc_to_page((void*)idev->info->mem[mi].addr);
 	get_page(page);
 	vmf->page = page;
 	return 0;
 }

 static struct vm_operations_struct uio_vm_ops = {
 	.open = uio_vma_open,
 	.close = uio_vma_close,
 	.fault = uio_vma_fault,
 };

 static int uio_mmap_physical(struct vm_area_struct *vma)
 {
 	struct uio_device *idev = vma->vm_private_data;
 	int mi = uio_find_mem_index(vma);
 	if (mi < 0)
 		return -EINVAL;

 	vma->vm_flags |= VM_IO | VM_RESERVED;

 	return remap_pfn_range(vma,
 			       vma->vm_start,
 			       idev->info->mem[mi].addr >> PAGE_SHIFT,
 			       vma->vm_end - vma->vm_start,
 			       vma->vm_page_prot);
 }

 static int uio_mmap_logical(struct vm_area_struct *vma)
 {
 	vma->vm_flags |= VM_RESERVED;
 	vma->vm_ops = &uio_vm_ops;
 	uio_vma_open(vma);
 	return 0;
 }

 static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
 {
 	struct uio_listener *listener = filep->private_data;
 	struct uio_device *idev = listener->dev;
 	int mi;
 	unsigned long requested_pages, actual_pages;
 	int ret = 0;

 	if (vma->vm_end < vma->vm_start)
 		return -EINVAL;

 	vma->vm_private_data = idev;

 	mi = uio_find_mem_index(vma);
 	if (mi < 0)
 		return -EINVAL;

 	requested_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 	actual_pages = (idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
 	if (requested_pages > actual_pages)
 		return -EINVAL;

 	if (idev->info->mmap) {
 		if (!try_module_get(idev->owner))
 			return -ENODEV;
 		ret = idev->info->mmap(idev->info, vma);
 		module_put(idev->owner);
 		return ret;
 	}

 	switch (idev->info->mem[mi].memtype) {
 		case UIO_MEM_PHYS:
 			return uio_mmap_physical(vma);
 		case UIO_MEM_LOGICAL:
 		case UIO_MEM_VIRTUAL:
 			return uio_mmap_logical(vma);
 		default:
 			return -EINVAL;
 	}
 }

 static const struct file_operations uio_fops = {
 	.owner		= THIS_MODULE,
 	.open		= uio_open,
 	.release	= uio_release,
 	.read		= uio_read,
 	.mmap		= uio_mmap,
 	.poll		= uio_poll,
 	.fasync		= uio_fasync,
 };

 static int uio_major_init(void)
 {
 	uio_major = register_chrdev(0, "uio", &uio_fops);
 	if (uio_major < 0)
 		return uio_major;
 	return 0;
 }

 static void uio_major_cleanup(void)
 {
 	unregister_chrdev(uio_major, "uio");
 }

 static int init_uio_class(void)
 {
 	int ret = 0;

 	if (uio_class != NULL) {
 		kref_get(&uio_class->kref);
 		goto exit;
 	}

 	/* This is the first time in here, set everything up properly */
 	ret = uio_major_init();
 	if (ret)
 		goto exit;

 	uio_class = kzalloc(sizeof(*uio_class), GFP_KERNEL);
 	if (!uio_class) {
 		ret = -ENOMEM;
 		goto err_kzalloc;
 	}

 	kref_init(&uio_class->kref);
 	uio_class->class = class_create(THIS_MODULE, "uio");
 	if (IS_ERR(uio_class->class)) {
 		ret = IS_ERR(uio_class->class);
 		printk(KERN_ERR "class_create failed for uio\n");
 		goto err_class_create;
 	}
 	return 0;

 err_class_create:
 	kfree(uio_class);
 	uio_class = NULL;
 err_kzalloc:
 	uio_major_cleanup();
 exit:
 	return ret;
 }

 static void release_uio_class(struct kref *kref)
 {
 	/* Ok, we cheat as we know we only have one uio_class */
 	class_destroy(uio_class->class);
 	kfree(uio_class);
 	uio_major_cleanup();
 	uio_class = NULL;
 }

 static void uio_class_destroy(void)
 {
 	if (uio_class)
 		kref_put(&uio_class->kref, release_uio_class);
 }

 /**
  * uio_register_device - register a new userspace IO device
  * @owner:	module that creates the new device
  * @parent:	parent device
  * @info:	UIO device capabilities
  *
  * returns zero on success or a negative error code.
  */
 int __uio_register_device(struct module *owner,
 			  struct device *parent,
 			  struct uio_info *info)
 {
 	struct uio_device *idev;
 	int ret = 0;

 	if (!parent || !info || !info->name || !info->version)
 		return -EINVAL;

 	info->uio_dev = NULL;

 	ret = init_uio_class();
 	if (ret)
 		return ret;

 	idev = kzalloc(sizeof(*idev), GFP_KERNEL);
 	if (!idev) {
 		ret = -ENOMEM;
 		goto err_kzalloc;
 	}

 	idev->owner = owner;
 	idev->info = info;
 	init_waitqueue_head(&idev->wait);
 	atomic_set(&idev->event, 0);

 	ret = uio_get_minor(idev);
 	if (ret)
 		goto err_get_minor;

 	idev->dev = device_create(uio_class->class, parent,
 				  MKDEV(uio_major, idev->minor),
 				  "uio%d", idev->minor);
 	if (IS_ERR(idev->dev)) {
 		printk(KERN_ERR "UIO: device register failed\n");
 		ret = PTR_ERR(idev->dev);
 		goto err_device_create;
 	}
 	dev_set_drvdata(idev->dev, idev);

 	ret = uio_dev_add_attributes(idev);
 	if (ret)
 		goto err_uio_dev_add_attributes;

 	info->uio_dev = idev;

 	if (idev->info->irq >= 0) {
 		ret = request_irq(idev->info->irq, uio_interrupt,
 				  idev->info->irq_flags, idev->info->name, idev);
 		if (ret)
 			goto err_request_irq;
 	}

 	return 0;

 err_request_irq:
 	uio_dev_del_attributes(idev);
 err_uio_dev_add_attributes:
 	device_destroy(uio_class->class, MKDEV(uio_major, idev->minor));
 err_device_create:
 	uio_free_minor(idev);
 err_get_minor:
 	kfree(idev);
 err_kzalloc:
 	uio_class_destroy();
 	return ret;
 }
 EXPORT_SYMBOL_GPL(__uio_register_device);

 /**
  * uio_unregister_device - unregister a industrial IO device
  * @info:	UIO device capabilities
  *
  */
 void uio_unregister_device(struct uio_info *info)
 {
 	struct uio_device *idev;

 	if (!info || !info->uio_dev)
 		return;

 	idev = info->uio_dev;

 	uio_free_minor(idev);

 	if (info->irq >= 0)
 		free_irq(info->irq, idev);

 	uio_dev_del_attributes(idev);

 	dev_set_drvdata(idev->dev, NULL);
 	device_destroy(uio_class->class, MKDEV(uio_major, idev->minor));
 	kfree(idev);
 	uio_class_destroy();

 	return;
 }
 EXPORT_SYMBOL_GPL(uio_unregister_device);

 static int __init uio_init(void)
 {
 	return 0;
 }

 static void __exit uio_exit(void)
 {
 }

 module_init(uio_init)
 module_exit(uio_exit)
 MODULE_LICENSE("GPL v2");
	/*
	* drivers/uio/uio.c
	*
	* Copyright(C) 2005, Benedikt Spranger <b.spranger@linutronix.de>
	* Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
	* Copyright(C) 2006, Hans J. Koch <hjk@linutronix.de>
	* Copyright(C) 2006, Greg Kroah-Hartman <greg@kroah.com>
	*
	* Userspace IO
	*
	* Base Functions
	*
	* Licensed under the GPLv2 only.
	*/

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/poll.h>
	#include <linux/device.h>
	#include <linux/mm.h>
	#include <linux/idr.h>
	#include <linux/string.h>
	#include <linux/kobject.h>
	#include <linux/uio_driver.h>

	#define UIO_MAX_DEVICES 255

	struct uio_device {
	struct module *owner;
	struct device *dev;
	int minor;
	atomic_t event;
	struct fasync_struct *async_queue;
	wait_queue_head_t wait;
	int vma_count;
	struct uio_info *info;
	struct kobject *map_dir;
	};

	static int uio_major;
	static DEFINE_IDR(uio_idr);
	static const struct file_operations uio_fops;

	/* UIO class infrastructure */
	static struct uio_class {
	struct kref kref;
	struct class *class;
	} *uio_class;

	/*
	* attributes
	*/

	struct uio_map {
	struct kobject kobj;
	struct uio_mem *mem;
	};
	#define to_map(map) container_of(map, struct uio_map, kobj)


	static ssize_t map_attr_show(struct kobject kobj, struct kobj_attribute attr,
	char *buf)
	{
	struct uio_map *map = to_map(kobj);
	struct uio_mem *mem = map->mem;

	if (strncmp(attr->attr.name, "addr", 4) == 0)
	return sprintf(buf, "0x%lx\n", mem->addr);

	if (strncmp(attr->attr.name, "size", 4) == 0)
	return sprintf(buf, "0x%lx\n", mem->size);

	return -ENODEV;
	}

	static struct kobj_attribute attr_attribute =
	__ATTR(addr, S_IRUGO, map_attr_show, NULL);
	static struct kobj_attribute size_attribute =
	__ATTR(size, S_IRUGO, map_attr_show, NULL);

	static struct attribute *attrs[] = {
	&attr_attribute.attr,
	&size_attribute.attr,
	NULL, /* need to NULL terminate the list of attributes */
	};

	static void map_release(struct kobject *kobj)
	{
	struct uio_map *map = to_map(kobj);
	kfree(map);
	}

	static struct kobj_type map_attr_type = {
	.release = map_release,
	.default_attrs = attrs,
	};

	static ssize_t show_name(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct uio_device *idev = dev_get_drvdata(dev);
	if (idev)
	return sprintf(buf, "%s\n", idev->info->name);
	else
	return -ENODEV;
	}
	static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

	static ssize_t show_version(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct uio_device *idev = dev_get_drvdata(dev);
	if (idev)
	return sprintf(buf, "%s\n", idev->info->version);
	else
	return -ENODEV;
	}
	static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);

	static ssize_t show_event(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct uio_device *idev = dev_get_drvdata(dev);
	if (idev)
	return sprintf(buf, "%u\n",
	(unsigned int)atomic_read(&idev->event));
	else
	return -ENODEV;
	}
	static DEVICE_ATTR(event, S_IRUGO, show_event, NULL);

	static struct attribute *uio_attrs[] = {
	&dev_attr_name.attr,
	&dev_attr_version.attr,
	&dev_attr_event.attr,
	NULL,
	};

	static struct attribute_group uio_attr_grp = {
	.attrs = uio_attrs,
	};

	/*
	* device functions
	*/
	static int uio_dev_add_attributes(struct uio_device *idev)
	{
	int ret;
	int mi;
	int map_found = 0;
	struct uio_mem *mem;
	struct uio_map *map;

	ret = sysfs_create_group(&idev->dev->kobj, &uio_attr_grp);
	if (ret)
	goto err_group;

	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
	mem = &idev->info->mem[mi];
	if (mem->size == 0)
	break;
	if (!map_found) {
	map_found = 1;
	idev->map_dir = kobject_create_and_add("maps",
	&idev->dev->kobj);
	if (!idev->map_dir)
	goto err;
	}
	map = kzalloc(sizeof(*map), GFP_KERNEL);
	if (!map)
	goto err;
	kobject_init(&map->kobj, &map_attr_type);
	map->mem = mem;
	mem->map = map;
	ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
	if (ret)
	goto err;
	ret = kobject_uevent(&map->kobj, KOBJ_ADD);
	if (ret)
	goto err;
	}

	return 0;

	err:
	for (mi--; mi>=0; mi--) {
	mem = &idev->info->mem[mi];
	map = mem->map;
	kobject_put(&map->kobj);
	}
	kobject_put(idev->map_dir);
	sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
	err_group:
	dev_err(idev->dev, "error creating sysfs files (%d)\n", ret);
	return ret;
	}

	static void uio_dev_del_attributes(struct uio_device *idev)
	{
	int mi;
	struct uio_mem *mem;
	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
	mem = &idev->info->mem[mi];
	if (mem->size == 0)
	break;
	kobject_put(&mem->map->kobj);
	}
	kobject_put(idev->map_dir);
	sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
	}

	static int uio_get_minor(struct uio_device *idev)
	{
	static DEFINE_MUTEX(minor_lock);
	int retval = -ENOMEM;
	int id;

	mutex_lock(&minor_lock);
	if (idr_pre_get(&uio_idr, GFP_KERNEL) == 0)
	goto exit;

	retval = idr_get_new(&uio_idr, idev, &id);
	if (retval < 0) {
	if (retval == -EAGAIN)
	retval = -ENOMEM;
	goto exit;
	}
	idev->minor = id & MAX_ID_MASK;
	exit:
	mutex_unlock(&minor_lock);
	return retval;
	}

	static void uio_free_minor(struct uio_device *idev)
	{
	idr_remove(&uio_idr, idev->minor);
	}

	/**
	* uio_event_notify - trigger an interrupt event
	* @info: UIO device capabilities
	*/
	void uio_event_notify(struct uio_info *info)
	{
	struct uio_device *idev = info->uio_dev;

	atomic_inc(&idev->event);
	wake_up_interruptible(&idev->wait);
	kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
	}
	EXPORT_SYMBOL_GPL(uio_event_notify);

	/**
	* uio_interrupt - hardware interrupt handler
	* @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
	* @dev_id: Pointer to the devices uio_device structure
	*/
	static irqreturn_t uio_interrupt(int irq, void *dev_id)
	{
	struct uio_device idev = (struct uio_device )dev_id;
	irqreturn_t ret = idev->info->handler(irq, idev->info);

	if (ret == IRQ_HANDLED)
	uio_event_notify(idev->info);

	return ret;
	}

	struct uio_listener {
	struct uio_device *dev;
	s32 event_count;
	};

	static int uio_open(struct inode inode, struct file filep)
	{
	struct uio_device *idev;
	struct uio_listener *listener;
	int ret = 0;

	idev = idr_find(&uio_idr, iminor(inode));
	if (!idev)
	return -ENODEV;

	listener = kmalloc(sizeof(*listener), GFP_KERNEL);
	if (!listener)
	return -ENOMEM;

	listener->dev = idev;
	listener->event_count = atomic_read(&idev->event);
	filep->private_data = listener;

	if (idev->info->open) {
	if (!try_module_get(idev->owner))
	return -ENODEV;
	ret = idev->info->open(idev->info, inode);
	module_put(idev->owner);
	}

	if (ret)
	kfree(listener);

	return ret;
	}

	static int uio_fasync(int fd, struct file *filep, int on)
	{
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;

	return fasync_helper(fd, filep, on, &idev->async_queue);
	}

	static int uio_release(struct inode inode, struct file filep)
	{
	int ret = 0;
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;

	if (idev->info->release) {
	if (!try_module_get(idev->owner))
	return -ENODEV;
	ret = idev->info->release(idev->info, inode);
	module_put(idev->owner);
	}
	if (filep->f_flags & FASYNC)
	ret = uio_fasync(-1, filep, 0);
	kfree(listener);
	return ret;
	}

	static unsigned int uio_poll(struct file filep, poll_table wait)
	{
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;

	if (idev->info->irq == UIO_IRQ_NONE)
	return -EIO;

	poll_wait(filep, &idev->wait, wait);
	if (listener->event_count != atomic_read(&idev->event))
	return POLLIN \| POLLRDNORM;
	return 0;
	}

	static ssize_t uio_read(struct file filep, char __user buf,
	size_t count, loff_t *ppos)
	{
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;
	DECLARE_WAITQUEUE(wait, current);
	ssize_t retval;
	s32 event_count;

	if (idev->info->irq == UIO_IRQ_NONE)
	return -EIO;

	if (count != sizeof(s32))
	return -EINVAL;

	add_wait_queue(&idev->wait, &wait);

	do {
	set_current_state(TASK_INTERRUPTIBLE);

	event_count = atomic_read(&idev->event);
	if (event_count != listener->event_count) {
	if (copy_to_user(buf, &event_count, count))
	retval = -EFAULT;
	else {
	listener->event_count = event_count;
	retval = count;
	}
	break;
	}

	if (filep->f_flags & O_NONBLOCK) {
	retval = -EAGAIN;
	break;
	}

	if (signal_pending(current)) {
	retval = -ERESTARTSYS;
	break;
	}
	schedule();
	} while (1);

	__set_current_state(TASK_RUNNING);
	remove_wait_queue(&idev->wait, &wait);

	return retval;
	}

	static int uio_find_mem_index(struct vm_area_struct *vma)
	{
	int mi;
	struct uio_device *idev = vma->vm_private_data;

	for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
	if (idev->info->mem[mi].size == 0)
	return -1;
	if (vma->vm_pgoff == mi)
	return mi;
	}
	return -1;
	}

	static void uio_vma_open(struct vm_area_struct *vma)
	{
	struct uio_device *idev = vma->vm_private_data;
	idev->vma_count++;
	}

	static void uio_vma_close(struct vm_area_struct *vma)
	{
	struct uio_device *idev = vma->vm_private_data;
	idev->vma_count--;
	}

	static int uio_vma_fault(struct vm_area_struct vma, struct vm_fault vmf)
	{
	struct uio_device *idev = vma->vm_private_data;
	struct page *page;

	int mi = uio_find_mem_index(vma);
	if (mi < 0)
	return VM_FAULT_SIGBUS;

	if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
	page = virt_to_page(idev->info->mem[mi].addr);
	else
	page = vmalloc_to_page((void*)idev->info->mem[mi].addr);
	get_page(page);
	vmf->page = page;
	return 0;
	}

	static struct vm_operations_struct uio_vm_ops = {
	.open = uio_vma_open,
	.close = uio_vma_close,
	.fault = uio_vma_fault,
	};

	static int uio_mmap_physical(struct vm_area_struct *vma)
	{
	struct uio_device *idev = vma->vm_private_data;
	int mi = uio_find_mem_index(vma);
	if (mi < 0)
	return -EINVAL;

	vma->vm_flags \|= VM_IO \| VM_RESERVED;

	return remap_pfn_range(vma,
	vma->vm_start,
	idev->info->mem[mi].addr >> PAGE_SHIFT,
	vma->vm_end - vma->vm_start,
	vma->vm_page_prot);
	}

	static int uio_mmap_logical(struct vm_area_struct *vma)
	{
	vma->vm_flags \|= VM_RESERVED;
	vma->vm_ops = &uio_vm_ops;
	uio_vma_open(vma);
	return 0;
	}

	static int uio_mmap(struct file filep, struct vm_area_struct vma)
	{
	struct uio_listener *listener = filep->private_data;
	struct uio_device *idev = listener->dev;
	int mi;
	unsigned long requested_pages, actual_pages;
	int ret = 0;

	if (vma->vm_end < vma->vm_start)
	return -EINVAL;

	vma->vm_private_data = idev;

	mi = uio_find_mem_index(vma);
	if (mi < 0)
	return -EINVAL;

	requested_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
	actual_pages = (idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
	if (requested_pages > actual_pages)
	return -EINVAL;

	if (idev->info->mmap) {
	if (!try_module_get(idev->owner))
	return -ENODEV;
	ret = idev->info->mmap(idev->info, vma);
	module_put(idev->owner);
	return ret;
	}

	switch (idev->info->mem[mi].memtype) {
	case UIO_MEM_PHYS:
	return uio_mmap_physical(vma);
	case UIO_MEM_LOGICAL:
	case UIO_MEM_VIRTUAL:
	return uio_mmap_logical(vma);
	default:
	return -EINVAL;
	}
	}

	static const struct file_operations uio_fops = {
	.owner = THIS_MODULE,
	.open = uio_open,
	.release = uio_release,
	.read = uio_read,
	.mmap = uio_mmap,
	.poll = uio_poll,
	.fasync = uio_fasync,
	};

	static int uio_major_init(void)
	{
	uio_major = register_chrdev(0, "uio", &uio_fops);
	if (uio_major < 0)
	return uio_major;
	return 0;
	}

	static void uio_major_cleanup(void)
	{
	unregister_chrdev(uio_major, "uio");
	}

	static int init_uio_class(void)
	{
	int ret = 0;

	if (uio_class != NULL) {
	kref_get(&uio_class->kref);
	goto exit;
	}

	/* This is the first time in here, set everything up properly */
	ret = uio_major_init();
	if (ret)
	goto exit;

	uio_class = kzalloc(sizeof(*uio_class), GFP_KERNEL);
	if (!uio_class) {
	ret = -ENOMEM;
	goto err_kzalloc;
	}

	kref_init(&uio_class->kref);
	uio_class->class = class_create(THIS_MODULE, "uio");
	if (IS_ERR(uio_class->class)) {
	ret = IS_ERR(uio_class->class);
	printk(KERN_ERR "class_create failed for uio\n");
	goto err_class_create;
	}
	return 0;

	err_class_create:
	kfree(uio_class);
	uio_class = NULL;
	err_kzalloc:
	uio_major_cleanup();
	exit:
	return ret;
	}

	static void release_uio_class(struct kref *kref)
	{
	/* Ok, we cheat as we know we only have one uio_class */
	class_destroy(uio_class->class);
	kfree(uio_class);
	uio_major_cleanup();
	uio_class = NULL;
	}

	static void uio_class_destroy(void)
	{
	if (uio_class)
	kref_put(&uio_class->kref, release_uio_class);
	}

	/**
	* uio_register_device - register a new userspace IO device
	* @owner: module that creates the new device
	* @parent: parent device
	* @info: UIO device capabilities
	*
	* returns zero on success or a negative error code.
	*/
	int __uio_register_device(struct module *owner,
	struct device *parent,
	struct uio_info *info)
	{
	struct uio_device *idev;
	int ret = 0;

	if (!parent \|\| !info \|\| !info->name \|\| !info->version)
	return -EINVAL;

	info->uio_dev = NULL;

	ret = init_uio_class();
	if (ret)
	return ret;

	idev = kzalloc(sizeof(*idev), GFP_KERNEL);
	if (!idev) {
	ret = -ENOMEM;
	goto err_kzalloc;
	}

	idev->owner = owner;
	idev->info = info;
	init_waitqueue_head(&idev->wait);
	atomic_set(&idev->event, 0);

	ret = uio_get_minor(idev);
	if (ret)
	goto err_get_minor;

	idev->dev = device_create(uio_class->class, parent,
	MKDEV(uio_major, idev->minor),
	"uio%d", idev->minor);
	if (IS_ERR(idev->dev)) {
	printk(KERN_ERR "UIO: device register failed\n");
	ret = PTR_ERR(idev->dev);
	goto err_device_create;
	}
	dev_set_drvdata(idev->dev, idev);

	ret = uio_dev_add_attributes(idev);
	if (ret)
	goto err_uio_dev_add_attributes;

	info->uio_dev = idev;

	if (idev->info->irq >= 0) {
	ret = request_irq(idev->info->irq, uio_interrupt,
	idev->info->irq_flags, idev->info->name, idev);
	if (ret)
	goto err_request_irq;
	}

	return 0;

	err_request_irq:
	uio_dev_del_attributes(idev);
	err_uio_dev_add_attributes:
	device_destroy(uio_class->class, MKDEV(uio_major, idev->minor));
	err_device_create:
	uio_free_minor(idev);
	err_get_minor:
	kfree(idev);
	err_kzalloc:
	uio_class_destroy();
	return ret;
	}
	EXPORT_SYMBOL_GPL(__uio_register_device);

	/**
	* uio_unregister_device - unregister a industrial IO device
	* @info: UIO device capabilities
	*
	*/
	void uio_unregister_device(struct uio_info *info)
	{
	struct uio_device *idev;

	if (!info \|\| !info->uio_dev)
	return;

	idev = info->uio_dev;

	uio_free_minor(idev);

	if (info->irq >= 0)
	free_irq(info->irq, idev);

	uio_dev_del_attributes(idev);

	dev_set_drvdata(idev->dev, NULL);
	device_destroy(uio_class->class, MKDEV(uio_major, idev->minor));
	kfree(idev);
	uio_class_destroy();

	return;
	}
	EXPORT_SYMBOL_GPL(uio_unregister_device);

	static int __init uio_init(void)
	{
	return 0;
	}

	static void __exit uio_exit(void)
	{
	}

	module_init(uio_init)
	module_exit(uio_exit)
	MODULE_LICENSE("GPL v2");