linux/drivers/uio/uio.c
Hans J. Koch beafc54c4e UIO: Add the User IO core code
This interface allows the ability to write the majority of a driver in
userspace with only a very small shell of a driver in the kernel itself.
It uses a char device and sysfs to interact with a userspace process to
process interrupts and control memory accesses.

See the docbook documentation for more details on how to use this
interface.

From: Hans J. Koch <hjk@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benedikt Spranger <b.spranger@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-18 15:57:15 -07:00

702 lines
15 KiB
C

/*
* 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 kset map_attr_kset;
};
static int uio_major;
static DEFINE_IDR(uio_idr);
static struct file_operations uio_fops;
/* UIO class infrastructure */
static struct uio_class {
struct kref kref;
struct class *class;
} *uio_class;
/*
* attributes
*/
static struct attribute attr_addr = {
.name = "addr",
.mode = S_IRUGO,
};
static struct attribute attr_size = {
.name = "size",
.mode = S_IRUGO,
};
static struct attribute* map_attrs[] = {
&attr_addr, &attr_size, NULL
};
static ssize_t map_attr_show(struct kobject *kobj, struct attribute *attr,
char *buf)
{
struct uio_mem *mem = container_of(kobj, struct uio_mem, kobj);
if (strncmp(attr->name,"addr",4) == 0)
return sprintf(buf, "0x%lx\n", mem->addr);
if (strncmp(attr->name,"size",4) == 0)
return sprintf(buf, "0x%lx\n", mem->size);
return -ENODEV;
}
static void map_attr_release(struct kobject *kobj)
{
/* TODO ??? */
}
static struct sysfs_ops map_attr_ops = {
.show = map_attr_show,
};
static struct kobj_type map_attr_type = {
.release = map_attr_release,
.sysfs_ops = &map_attr_ops,
.default_attrs = map_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;
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;
kobject_set_name(&idev->map_attr_kset.kobj,"maps");
idev->map_attr_kset.ktype = &map_attr_type;
idev->map_attr_kset.kobj.parent = &idev->dev->kobj;
ret = kset_register(&idev->map_attr_kset);
if (ret)
goto err_remove_group;
}
kobject_init(&mem->kobj);
kobject_set_name(&mem->kobj,"map%d",mi);
mem->kobj.parent = &idev->map_attr_kset.kobj;
mem->kobj.kset = &idev->map_attr_kset;
ret = kobject_add(&mem->kobj);
if (ret)
goto err_remove_maps;
}
return 0;
err_remove_maps:
for (mi--; mi>=0; mi--) {
mem = &idev->info->mem[mi];
kobject_unregister(&mem->kobj);
}
kset_unregister(&idev->map_attr_kset); /* Needed ? */
err_remove_group:
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_unregister(&mem->kobj);
}
kset_unregister(&idev->map_attr_kset);
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 struct page *uio_vma_nopage(struct vm_area_struct *vma,
unsigned long address, int *type)
{
struct uio_device *idev = vma->vm_private_data;
struct page* page = NOPAGE_SIGBUS;
int mi = uio_find_mem_index(vma);
if (mi < 0)
return page;
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);
if (type)
*type = VM_FAULT_MINOR;
return page;
}
static struct vm_operations_struct uio_vm_ops = {
.open = uio_vma_open,
.close = uio_vma_close,
.nopage = uio_vma_nopage,
};
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 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");