linux/drivers/uio/uio.c

929 lines
20 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/sched.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;
struct kobject *portio_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;
/* Protect idr accesses */
static DEFINE_MUTEX(minor_lock);
/*
* 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_name_show(struct uio_mem *mem, char *buf)
{
if (unlikely(!mem->name))
mem->name = "";
return sprintf(buf, "%s\n", mem->name);
}
static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
{
return sprintf(buf, "0x%lx\n", mem->addr);
}
static ssize_t map_size_show(struct uio_mem *mem, char *buf)
{
return sprintf(buf, "0x%lx\n", mem->size);
}
static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
{
return sprintf(buf, "0x%lx\n", mem->addr & ~PAGE_MASK);
}
struct map_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct uio_mem *, char *);
ssize_t (*store)(struct uio_mem *, const char *, size_t);
};
static struct map_sysfs_entry name_attribute =
__ATTR(name, S_IRUGO, map_name_show, NULL);
static struct map_sysfs_entry addr_attribute =
__ATTR(addr, S_IRUGO, map_addr_show, NULL);
static struct map_sysfs_entry size_attribute =
__ATTR(size, S_IRUGO, map_size_show, NULL);
static struct map_sysfs_entry offset_attribute =
__ATTR(offset, S_IRUGO, map_offset_show, NULL);
static struct attribute *attrs[] = {
&name_attribute.attr,
&addr_attribute.attr,
&size_attribute.attr,
&offset_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 ssize_t map_type_show(struct kobject *kobj, struct attribute *attr,
char *buf)
{
struct uio_map *map = to_map(kobj);
struct uio_mem *mem = map->mem;
struct map_sysfs_entry *entry;
entry = container_of(attr, struct map_sysfs_entry, attr);
if (!entry->show)
return -EIO;
return entry->show(mem, buf);
}
static const struct sysfs_ops map_sysfs_ops = {
.show = map_type_show,
};
static struct kobj_type map_attr_type = {
.release = map_release,
.sysfs_ops = &map_sysfs_ops,
.default_attrs = attrs,
};
struct uio_portio {
struct kobject kobj;
struct uio_port *port;
};
#define to_portio(portio) container_of(portio, struct uio_portio, kobj)
static ssize_t portio_name_show(struct uio_port *port, char *buf)
{
if (unlikely(!port->name))
port->name = "";
return sprintf(buf, "%s\n", port->name);
}
static ssize_t portio_start_show(struct uio_port *port, char *buf)
{
return sprintf(buf, "0x%lx\n", port->start);
}
static ssize_t portio_size_show(struct uio_port *port, char *buf)
{
return sprintf(buf, "0x%lx\n", port->size);
}
static ssize_t portio_porttype_show(struct uio_port *port, char *buf)
{
const char *porttypes[] = {"none", "x86", "gpio", "other"};
if ((port->porttype < 0) || (port->porttype > UIO_PORT_OTHER))
return -EINVAL;
return sprintf(buf, "port_%s\n", porttypes[port->porttype]);
}
struct portio_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct uio_port *, char *);
ssize_t (*store)(struct uio_port *, const char *, size_t);
};
static struct portio_sysfs_entry portio_name_attribute =
__ATTR(name, S_IRUGO, portio_name_show, NULL);
static struct portio_sysfs_entry portio_start_attribute =
__ATTR(start, S_IRUGO, portio_start_show, NULL);
static struct portio_sysfs_entry portio_size_attribute =
__ATTR(size, S_IRUGO, portio_size_show, NULL);
static struct portio_sysfs_entry portio_porttype_attribute =
__ATTR(porttype, S_IRUGO, portio_porttype_show, NULL);
static struct attribute *portio_attrs[] = {
&portio_name_attribute.attr,
&portio_start_attribute.attr,
&portio_size_attribute.attr,
&portio_porttype_attribute.attr,
NULL,
};
static void portio_release(struct kobject *kobj)
{
struct uio_portio *portio = to_portio(kobj);
kfree(portio);
}
static ssize_t portio_type_show(struct kobject *kobj, struct attribute *attr,
char *buf)
{
struct uio_portio *portio = to_portio(kobj);
struct uio_port *port = portio->port;
struct portio_sysfs_entry *entry;
entry = container_of(attr, struct portio_sysfs_entry, attr);
if (!entry->show)
return -EIO;
return entry->show(port, buf);
}
static const struct sysfs_ops portio_sysfs_ops = {
.show = portio_type_show,
};
static struct kobj_type portio_attr_type = {
.release = portio_release,
.sysfs_ops = &portio_sysfs_ops,
.default_attrs = portio_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, pi;
int map_found = 0;
int portio_found = 0;
struct uio_mem *mem;
struct uio_map *map;
struct uio_port *port;
struct uio_portio *portio;
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;
}
map = kzalloc(sizeof(*map), GFP_KERNEL);
if (!map)
goto err_map;
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_map;
ret = kobject_uevent(&map->kobj, KOBJ_ADD);
if (ret)
goto err_map;
}
for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
port = &idev->info->port[pi];
if (port->size == 0)
break;
if (!portio_found) {
portio_found = 1;
idev->portio_dir = kobject_create_and_add("portio",
&idev->dev->kobj);
if (!idev->portio_dir)
goto err_portio;
}
portio = kzalloc(sizeof(*portio), GFP_KERNEL);
if (!portio)
goto err_portio;
kobject_init(&portio->kobj, &portio_attr_type);
portio->port = port;
port->portio = portio;
ret = kobject_add(&portio->kobj, idev->portio_dir,
"port%d", pi);
if (ret)
goto err_portio;
ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
if (ret)
goto err_portio;
}
return 0;
err_portio:
for (pi--; pi >= 0; pi--) {
port = &idev->info->port[pi];
portio = port->portio;
kobject_put(&portio->kobj);
}
kobject_put(idev->portio_dir);
err_map:
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 i;
struct uio_mem *mem;
struct uio_port *port;
for (i = 0; i < MAX_UIO_MAPS; i++) {
mem = &idev->info->mem[i];
if (mem->size == 0)
break;
kobject_put(&mem->map->kobj);
}
kobject_put(idev->map_dir);
for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
port = &idev->info->port[i];
if (port->size == 0)
break;
kobject_put(&port->portio->kobj);
}
kobject_put(idev->portio_dir);
sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
}
static int uio_get_minor(struct uio_device *idev)
{
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)
{
mutex_lock(&minor_lock);
idr_remove(&uio_idr, idev->minor);
mutex_unlock(&minor_lock);
}
/**
* 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;
mutex_lock(&minor_lock);
idev = idr_find(&uio_idr, iminor(inode));
mutex_unlock(&minor_lock);
if (!idev) {
ret = -ENODEV;
goto out;
}
if (!try_module_get(idev->owner)) {
ret = -ENODEV;
goto out;
}
listener = kmalloc(sizeof(*listener), GFP_KERNEL);
if (!listener) {
ret = -ENOMEM;
goto err_alloc_listener;
}
listener->dev = idev;
listener->event_count = atomic_read(&idev->event);
filep->private_data = listener;
if (idev->info->open) {
ret = idev->info->open(idev->info, inode);
if (ret)
goto err_infoopen;
}
return 0;
err_infoopen:
kfree(listener);
err_alloc_listener:
module_put(idev->owner);
out:
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)
ret = idev->info->release(idev->info, inode);
module_put(idev->owner);
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 ssize_t uio_write(struct file *filep, const char __user *buf,
size_t count, loff_t *ppos)
{
struct uio_listener *listener = filep->private_data;
struct uio_device *idev = listener->dev;
ssize_t retval;
s32 irq_on;
if (idev->info->irq == UIO_IRQ_NONE)
return -EIO;
if (count != sizeof(s32))
return -EINVAL;
if (!idev->info->irqcontrol)
return -ENOSYS;
if (copy_from_user(&irq_on, buf, count))
return -EFAULT;
retval = idev->info->irqcontrol(idev->info, irq_on);
return retval ? retval : sizeof(s32);
}
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;
unsigned long offset;
int mi = uio_find_mem_index(vma);
if (mi < 0)
return VM_FAULT_SIGBUS;
/*
* We need to subtract mi because userspace uses offset = N*PAGE_SIZE
* to use mem[N].
*/
offset = (vmf->pgoff - mi) << PAGE_SHIFT;
if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
page = virt_to_page(idev->info->mem[mi].addr + offset);
else
page = vmalloc_to_page((void *)idev->info->mem[mi].addr
+ offset);
get_page(page);
vmf->page = page;
return 0;
}
static const 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;
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
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].addr & ~PAGE_MASK)
+ idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
if (requested_pages > actual_pages)
return -EINVAL;
if (idev->info->mmap) {
ret = idev->info->mmap(idev->info, vma);
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,
.write = uio_write,
.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), idev,
"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;
}
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");