/* * 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; /* 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_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 uio_sysfs_entry { struct attribute attr; ssize_t (*show)(struct uio_mem *, char *); ssize_t (*store)(struct uio_mem *, const char *, size_t); }; static struct uio_sysfs_entry addr_attribute = __ATTR(addr, S_IRUGO, map_addr_show, NULL); static struct uio_sysfs_entry size_attribute = __ATTR(size, S_IRUGO, map_size_show, NULL); static struct uio_sysfs_entry offset_attribute = __ATTR(offset, S_IRUGO, map_offset_show, NULL); static struct attribute *attrs[] = { &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 uio_sysfs_entry *entry; entry = container_of(attr, struct uio_sysfs_entry, attr); if (!entry->show) return -EIO; return entry->show(mem, buf); } static struct sysfs_ops uio_sysfs_ops = { .show = map_type_show, }; static struct kobj_type map_attr_type = { .release = map_release, .sysfs_ops = &uio_sysfs_ops, .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) { 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); 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 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 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].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");