drivers/uio/uio.c

   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@hansjkoch.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/slab.h>
  21 #include <linux/mm.h>
  22 #include <linux/idr.h>
  23 #include <linux/sched.h>
  24 #include <linux/string.h>
  25 #include <linux/kobject.h>
  26 #include <linux/cdev.h>
  27 #include <linux/uio_driver.h>
  28
  29 #define UIO_MAX_DEVICES         (1U << MINORBITS)
  30
  31 struct uio_device {
  32         struct module           *owner;
  33         struct device           *dev;
  34         int                     minor;
  35         atomic_t                event;
  36         struct fasync_struct    *async_queue;
  37         wait_queue_head_t       wait;
  38         struct uio_info         *info;
  39         struct kobject          *map_dir;
  40         struct kobject          *portio_dir;
  41 };
  42
  43 static int uio_major;
  44 static struct cdev *uio_cdev;
  45 static DEFINE_IDR(uio_idr);
  46 static const struct file_operations uio_fops;
  47
  48 /* Protect idr accesses */
  49 static DEFINE_MUTEX(minor_lock);
  50
  51 /*
  52  * attributes
  53  */
  54
  55 struct uio_map {
  56         struct kobject kobj;
  57         struct uio_mem *mem;
  58 };
  59 #define to_map(map) container_of(map, struct uio_map, kobj)
  60
  61 static ssize_t map_name_show(struct uio_mem *mem, char *buf)
  62 {
  63         if (unlikely(!mem->name))
  64                 mem->name = "";
  65
  66         return sprintf(buf, "%s\n", mem->name);
  67 }
  68
  69 static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
  70 {
  71         return sprintf(buf, "0x%llx\n", (unsigned long long)mem->addr);
  72 }
  73
  74 static ssize_t map_size_show(struct uio_mem *mem, char *buf)
  75 {
  76         return sprintf(buf, "0x%lx\n", mem->size);
  77 }
  78
  79 static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
  80 {
  81         return sprintf(buf, "0x%llx\n", (unsigned long long)mem->addr & ~PAGE_MASK);
  82 }
  83
  84 struct map_sysfs_entry {
  85         struct attribute attr;
  86         ssize_t (*show)(struct uio_mem *, char *);
  87         ssize_t (*store)(struct uio_mem *, const char *, size_t);
  88 };
  89
  90 static struct map_sysfs_entry name_attribute =
  91         __ATTR(name, S_IRUGO, map_name_show, NULL);
  92 static struct map_sysfs_entry addr_attribute =
  93         __ATTR(addr, S_IRUGO, map_addr_show, NULL);
  94 static struct map_sysfs_entry size_attribute =
  95         __ATTR(size, S_IRUGO, map_size_show, NULL);
  96 static struct map_sysfs_entry offset_attribute =
  97         __ATTR(offset, S_IRUGO, map_offset_show, NULL);
  98
  99 static struct attribute *attrs[] = {
 100         &name_attribute.attr,
 101         &addr_attribute.attr,
 102         &size_attribute.attr,
 103         &offset_attribute.attr,
 104         NULL,   /* need to NULL terminate the list of attributes */
 105 };
 106
 107 static void map_release(struct kobject *kobj)
 108 {
 109         struct uio_map *map = to_map(kobj);
 110         kfree(map);
 111 }
 112
 113 static ssize_t map_type_show(struct kobject *kobj, struct attribute *attr,
 114                              char *buf)
 115 {
 116         struct uio_map *map = to_map(kobj);
 117         struct uio_mem *mem = map->mem;
 118         struct map_sysfs_entry *entry;
 119
 120         entry = container_of(attr, struct map_sysfs_entry, attr);
 121
 122         if (!entry->show)
 123                 return -EIO;
 124
 125         return entry->show(mem, buf);
 126 }
 127
 128 static const struct sysfs_ops map_sysfs_ops = {
 129         .show = map_type_show,
 130 };
 131
 132 static struct kobj_type map_attr_type = {
 133         .release        = map_release,
 134         .sysfs_ops      = &map_sysfs_ops,
 135         .default_attrs  = attrs,
 136 };
 137
 138 struct uio_portio {
 139         struct kobject kobj;
 140         struct uio_port *port;
 141 };
 142 #define to_portio(portio) container_of(portio, struct uio_portio, kobj)
 143
 144 static ssize_t portio_name_show(struct uio_port *port, char *buf)
 145 {
 146         if (unlikely(!port->name))
 147                 port->name = "";
 148
 149         return sprintf(buf, "%s\n", port->name);
 150 }
 151
 152 static ssize_t portio_start_show(struct uio_port *port, char *buf)
 153 {
 154         return sprintf(buf, "0x%lx\n", port->start);
 155 }
 156
 157 static ssize_t portio_size_show(struct uio_port *port, char *buf)
 158 {
 159         return sprintf(buf, "0x%lx\n", port->size);
 160 }
 161
 162 static ssize_t portio_porttype_show(struct uio_port *port, char *buf)
 163 {
 164         const char *porttypes[] = {"none", "x86", "gpio", "other"};
 165
 166         if ((port->porttype < 0) || (port->porttype > UIO_PORT_OTHER))
 167                 return -EINVAL;
 168
 169         return sprintf(buf, "port_%s\n", porttypes[port->porttype]);
 170 }
 171
 172 struct portio_sysfs_entry {
 173         struct attribute attr;
 174         ssize_t (*show)(struct uio_port *, char *);
 175         ssize_t (*store)(struct uio_port *, const char *, size_t);
 176 };
 177
 178 static struct portio_sysfs_entry portio_name_attribute =
 179         __ATTR(name, S_IRUGO, portio_name_show, NULL);
 180 static struct portio_sysfs_entry portio_start_attribute =
 181         __ATTR(start, S_IRUGO, portio_start_show, NULL);
 182 static struct portio_sysfs_entry portio_size_attribute =
 183         __ATTR(size, S_IRUGO, portio_size_show, NULL);
 184 static struct portio_sysfs_entry portio_porttype_attribute =
 185         __ATTR(porttype, S_IRUGO, portio_porttype_show, NULL);
 186
 187 static struct attribute *portio_attrs[] = {
 188         &portio_name_attribute.attr,
 189         &portio_start_attribute.attr,
 190         &portio_size_attribute.attr,
 191         &portio_porttype_attribute.attr,
 192         NULL,
 193 };
 194
 195 static void portio_release(struct kobject *kobj)
 196 {
 197         struct uio_portio *portio = to_portio(kobj);
 198         kfree(portio);
 199 }
 200
 201 static ssize_t portio_type_show(struct kobject *kobj, struct attribute *attr,
 202                              char *buf)
 203 {
 204         struct uio_portio *portio = to_portio(kobj);
 205         struct uio_port *port = portio->port;
 206         struct portio_sysfs_entry *entry;
 207
 208         entry = container_of(attr, struct portio_sysfs_entry, attr);
 209
 210         if (!entry->show)
 211                 return -EIO;
 212
 213         return entry->show(port, buf);
 214 }
 215
 216 static const struct sysfs_ops portio_sysfs_ops = {
 217         .show = portio_type_show,
 218 };
 219
 220 static struct kobj_type portio_attr_type = {
 221         .release        = portio_release,
 222         .sysfs_ops      = &portio_sysfs_ops,
 223         .default_attrs  = portio_attrs,
 224 };
 225
 226 static ssize_t name_show(struct device *dev,
 227                          struct device_attribute *attr, char *buf)
 228 {
 229         struct uio_device *idev = dev_get_drvdata(dev);
 230         return sprintf(buf, "%s\n", idev->info->name);
 231 }
 232 static DEVICE_ATTR_RO(name);
 233
 234 static ssize_t version_show(struct device *dev,
 235                             struct device_attribute *attr, char *buf)
 236 {
 237         struct uio_device *idev = dev_get_drvdata(dev);
 238         return sprintf(buf, "%s\n", idev->info->version);
 239 }
 240 static DEVICE_ATTR_RO(version);
 241
 242 static ssize_t event_show(struct device *dev,
 243                           struct device_attribute *attr, char *buf)
 244 {
 245         struct uio_device *idev = dev_get_drvdata(dev);
 246         return sprintf(buf, "%u\n", (unsigned int)atomic_read(&idev->event));
 247 }
 248 static DEVICE_ATTR_RO(event);
 249
 250 static struct attribute *uio_attrs[] = {
 251         &dev_attr_name.attr,
 252         &dev_attr_version.attr,
 253         &dev_attr_event.attr,
 254         NULL,
 255 };
 256 ATTRIBUTE_GROUPS(uio);
 257
 258 /* UIO class infrastructure */
 259 static struct class uio_class = {
 260         .name = "uio",
 261         .dev_groups = uio_groups,
 262 };
 263
 264 /*
 265  * device functions
 266  */
 267 static int uio_dev_add_attributes(struct uio_device *idev)
 268 {
 269         int ret;
 270         int mi, pi;
 271         int map_found = 0;
 272         int portio_found = 0;
 273         struct uio_mem *mem;
 274         struct uio_map *map;
 275         struct uio_port *port;
 276         struct uio_portio *portio;
 277
 278         for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
 279                 mem = &idev->info->mem[mi];
 280                 if (mem->size == 0)
 281                         break;
 282                 if (!map_found) {
 283                         map_found = 1;
 284                         idev->map_dir = kobject_create_and_add("maps",
 285                                                         &idev->dev->kobj);
 286                         if (!idev->map_dir)
 287                                 goto err_map;
 288                 }
 289                 map = kzalloc(sizeof(*map), GFP_KERNEL);
 290                 if (!map)
 291                         goto err_map_kobj;
 292                 kobject_init(&map->kobj, &map_attr_type);
 293                 map->mem = mem;
 294                 mem->map = map;
 295                 ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
 296                 if (ret)
 297                         goto err_map_kobj;
 298                 ret = kobject_uevent(&map->kobj, KOBJ_ADD);
 299                 if (ret)
 300                         goto err_map;
 301         }
 302
 303         for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
 304                 port = &idev->info->port[pi];
 305                 if (port->size == 0)
 306                         break;
 307                 if (!portio_found) {
 308                         portio_found = 1;
 309                         idev->portio_dir = kobject_create_and_add("portio",
 310                                                         &idev->dev->kobj);
 311                         if (!idev->portio_dir)
 312                                 goto err_portio;
 313                 }
 314                 portio = kzalloc(sizeof(*portio), GFP_KERNEL);
 315                 if (!portio)
 316                         goto err_portio_kobj;
 317                 kobject_init(&portio->kobj, &portio_attr_type);
 318                 portio->port = port;
 319                 port->portio = portio;
 320                 ret = kobject_add(&portio->kobj, idev->portio_dir,
 321                                                         "port%d", pi);
 322                 if (ret)
 323                         goto err_portio_kobj;
 324                 ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
 325                 if (ret)
 326                         goto err_portio;
 327         }
 328
 329         return 0;
 330
 331 err_portio:
 332         pi--;
 333 err_portio_kobj:
 334         for (; pi >= 0; pi--) {
 335                 port = &idev->info->port[pi];
 336                 portio = port->portio;
 337                 kobject_put(&portio->kobj);
 338         }
 339         kobject_put(idev->portio_dir);
 340 err_map:
 341         mi--;
 342 err_map_kobj:
 343         for (; mi >= 0; mi--) {
 344                 mem = &idev->info->mem[mi];
 345                 map = mem->map;
 346                 kobject_put(&map->kobj);
 347         }
 348         kobject_put(idev->map_dir);
 349         dev_err(idev->dev, "error creating sysfs files (%d)\n", ret);
 350         return ret;
 351 }
 352
 353 static void uio_dev_del_attributes(struct uio_device *idev)
 354 {
 355         int i;
 356         struct uio_mem *mem;
 357         struct uio_port *port;
 358
 359         for (i = 0; i < MAX_UIO_MAPS; i++) {
 360                 mem = &idev->info->mem[i];
 361                 if (mem->size == 0)
 362                         break;
 363                 kobject_put(&mem->map->kobj);
 364         }
 365         kobject_put(idev->map_dir);
 366
 367         for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
 368                 port = &idev->info->port[i];
 369                 if (port->size == 0)
 370                         break;
 371                 kobject_put(&port->portio->kobj);
 372         }
 373         kobject_put(idev->portio_dir);
 374 }
 375
 376 static int uio_get_minor(struct uio_device *idev)
 377 {
 378         int retval = -ENOMEM;
 379
 380         mutex_lock(&minor_lock);
 381         retval = idr_alloc(&uio_idr, idev, 0, UIO_MAX_DEVICES, GFP_KERNEL);
 382         if (retval >= 0) {
 383                 idev->minor = retval;
 384                 retval = 0;
 385         } else if (retval == -ENOSPC) {
 386                 dev_err(idev->dev, "too many uio devices\n");
 387                 retval = -EINVAL;
 388         }
 389         mutex_unlock(&minor_lock);
 390         return retval;
 391 }
 392
 393 static void uio_free_minor(struct uio_device *idev)
 394 {
 395         mutex_lock(&minor_lock);
 396         idr_remove(&uio_idr, idev->minor);
 397         mutex_unlock(&minor_lock);
 398 }
 399
 400 /**
 401  * uio_event_notify - trigger an interrupt event
 402  * @info: UIO device capabilities
 403  */
 404 void uio_event_notify(struct uio_info *info)
 405 {
 406         struct uio_device *idev = info->uio_dev;
 407
 408         atomic_inc(&idev->event);
 409         wake_up_interruptible(&idev->wait);
 410         kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
 411 }
 412 EXPORT_SYMBOL_GPL(uio_event_notify);
 413
 414 /**
 415  * uio_interrupt - hardware interrupt handler
 416  * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
 417  * @dev_id: Pointer to the devices uio_device structure
 418  */
 419 static irqreturn_t uio_interrupt(int irq, void *dev_id)
 420 {
 421         struct uio_device *idev = (struct uio_device *)dev_id;
 422         irqreturn_t ret = idev->info->handler(irq, idev->info);
 423
 424         if (ret == IRQ_HANDLED)
 425                 uio_event_notify(idev->info);
 426
 427         return ret;
 428 }
 429
 430 struct uio_listener {
 431         struct uio_device *dev;
 432         s32 event_count;
 433 };
 434
 435 static int uio_open(struct inode *inode, struct file *filep)
 436 {
 437         struct uio_device *idev;
 438         struct uio_listener *listener;
 439         int ret = 0;
 440
 441         mutex_lock(&minor_lock);
 442         idev = idr_find(&uio_idr, iminor(inode));
 443         mutex_unlock(&minor_lock);
 444         if (!idev) {
 445                 ret = -ENODEV;
 446                 goto out;
 447         }
 448
 449         if (!try_module_get(idev->owner)) {
 450                 ret = -ENODEV;
 451                 goto out;
 452         }
 453
 454         listener = kmalloc(sizeof(*listener), GFP_KERNEL);
 455         if (!listener) {
 456                 ret = -ENOMEM;
 457                 goto err_alloc_listener;
 458         }
 459
 460         listener->dev = idev;
 461         listener->event_count = atomic_read(&idev->event);
 462         filep->private_data = listener;
 463
 464         if (idev->info->open) {
 465                 ret = idev->info->open(idev->info, inode);
 466                 if (ret)
 467                         goto err_infoopen;
 468         }
 469         return 0;
 470
 471 err_infoopen:
 472         kfree(listener);
 473
 474 err_alloc_listener:
 475         module_put(idev->owner);
 476
 477 out:
 478         return ret;
 479 }
 480
 481 static int uio_fasync(int fd, struct file *filep, int on)
 482 {
 483         struct uio_listener *listener = filep->private_data;
 484         struct uio_device *idev = listener->dev;
 485
 486         return fasync_helper(fd, filep, on, &idev->async_queue);
 487 }
 488
 489 static int uio_release(struct inode *inode, struct file *filep)
 490 {
 491         int ret = 0;
 492         struct uio_listener *listener = filep->private_data;
 493         struct uio_device *idev = listener->dev;
 494
 495         if (idev->info->release)
 496                 ret = idev->info->release(idev->info, inode);
 497
 498         module_put(idev->owner);
 499         kfree(listener);
 500         return ret;
 501 }
 502
 503 static unsigned int uio_poll(struct file *filep, poll_table *wait)
 504 {
 505         struct uio_listener *listener = filep->private_data;
 506         struct uio_device *idev = listener->dev;
 507
 508         if (!idev->info->irq)
 509                 return -EIO;
 510
 511         poll_wait(filep, &idev->wait, wait);
 512         if (listener->event_count != atomic_read(&idev->event))
 513                 return POLLIN | POLLRDNORM;
 514         return 0;
 515 }
 516
 517 static ssize_t uio_read(struct file *filep, char __user *buf,
 518                         size_t count, loff_t *ppos)
 519 {
 520         struct uio_listener *listener = filep->private_data;
 521         struct uio_device *idev = listener->dev;
 522         DECLARE_WAITQUEUE(wait, current);
 523         ssize_t retval;
 524         s32 event_count;
 525
 526         if (!idev->info->irq)
 527                 return -EIO;
 528
 529         if (count != sizeof(s32))
 530                 return -EINVAL;
 531
 532         add_wait_queue(&idev->wait, &wait);
 533
 534         do {
 535                 set_current_state(TASK_INTERRUPTIBLE);
 536
 537                 event_count = atomic_read(&idev->event);
 538                 if (event_count != listener->event_count) {
 539                         if (copy_to_user(buf, &event_count, count))
 540                                 retval = -EFAULT;
 541                         else {
 542                                 listener->event_count = event_count;
 543                                 retval = count;
 544                         }
 545                         break;
 546                 }
 547
 548                 if (filep->f_flags & O_NONBLOCK) {
 549                         retval = -EAGAIN;
 550                         break;
 551                 }
 552
 553                 if (signal_pending(current)) {
 554                         retval = -ERESTARTSYS;
 555                         break;
 556                 }
 557                 schedule();
 558         } while (1);
 559
 560         __set_current_state(TASK_RUNNING);
 561         remove_wait_queue(&idev->wait, &wait);
 562
 563         return retval;
 564 }
 565
 566 static ssize_t uio_write(struct file *filep, const char __user *buf,
 567                         size_t count, loff_t *ppos)
 568 {
 569         struct uio_listener *listener = filep->private_data;
 570         struct uio_device *idev = listener->dev;
 571         ssize_t retval;
 572         s32 irq_on;
 573
 574         if (!idev->info->irq)
 575                 return -EIO;
 576
 577         if (count != sizeof(s32))
 578                 return -EINVAL;
 579
 580         if (!idev->info->irqcontrol)
 581                 return -ENOSYS;
 582
 583         if (copy_from_user(&irq_on, buf, count))
 584                 return -EFAULT;
 585
 586         retval = idev->info->irqcontrol(idev->info, irq_on);
 587
 588         return retval ? retval : sizeof(s32);
 589 }
 590
 591 static int uio_find_mem_index(struct vm_area_struct *vma)
 592 {
 593         struct uio_device *idev = vma->vm_private_data;
 594
 595         if (vma->vm_pgoff < MAX_UIO_MAPS) {
 596                 if (idev->info->mem[vma->vm_pgoff].size == 0)
 597                         return -1;
 598                 return (int)vma->vm_pgoff;
 599         }
 600         return -1;
 601 }
 602
 603 static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 604 {
 605         struct uio_device *idev = vma->vm_private_data;
 606         struct page *page;
 607         unsigned long offset;
 608         void *addr;
 609
 610         int mi = uio_find_mem_index(vma);
 611         if (mi < 0)
 612                 return VM_FAULT_SIGBUS;
 613
 614         /*
 615          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
 616          * to use mem[N].
 617          */
 618         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
 619
 620         addr = (void *)(unsigned long)idev->info->mem[mi].addr + offset;
 621         if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
 622                 page = virt_to_page(addr);
 623         else
 624                 page = vmalloc_to_page(addr);
 625         get_page(page);
 626         vmf->page = page;
 627         return 0;
 628 }
 629
 630 static const struct vm_operations_struct uio_logical_vm_ops = {
 631         .fault = uio_vma_fault,
 632 };
 633
 634 static int uio_mmap_logical(struct vm_area_struct *vma)
 635 {
 636         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
 637         vma->vm_ops = &uio_logical_vm_ops;
 638         return 0;
 639 }
 640
 641 static const struct vm_operations_struct uio_physical_vm_ops = {
 642 #ifdef CONFIG_HAVE_IOREMAP_PROT
 643         .access = generic_access_phys,
 644 #endif
 645 };
 646
 647 static int uio_mmap_physical(struct vm_area_struct *vma)
 648 {
 649         struct uio_device *idev = vma->vm_private_data;
 650         int mi = uio_find_mem_index(vma);
 651         struct uio_mem *mem;
 652         if (mi < 0)
 653                 return -EINVAL;
 654         mem = idev->info->mem + mi;
 655
 656         if (mem->addr & ~PAGE_MASK)
 657                 return -ENODEV;
 658         if (vma->vm_end - vma->vm_start > mem->size)
 659                 return -EINVAL;
 660
 661         vma->vm_ops = &uio_physical_vm_ops;
 662         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 663
 664         /*
 665          * We cannot use the vm_iomap_memory() helper here,
 666          * because vma->vm_pgoff is the map index we looked
 667          * up above in uio_find_mem_index(), rather than an
 668          * actual page offset into the mmap.
 669          *
 670          * So we just do the physical mmap without a page
 671          * offset.
 672          */
 673         return remap_pfn_range(vma,
 674                                vma->vm_start,
 675                                mem->addr >> PAGE_SHIFT,
 676                                vma->vm_end - vma->vm_start,
 677                                vma->vm_page_prot);
 678 }
 679
 680 static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
 681 {
 682         struct uio_listener *listener = filep->private_data;
 683         struct uio_device *idev = listener->dev;
 684         int mi;
 685         unsigned long requested_pages, actual_pages;
 686         int ret = 0;
 687
 688         if (vma->vm_end < vma->vm_start)
 689                 return -EINVAL;
 690
 691         vma->vm_private_data = idev;
 692
 693         mi = uio_find_mem_index(vma);
 694         if (mi < 0)
 695                 return -EINVAL;
 696
 697         requested_pages = vma_pages(vma);
 698         actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
 699                         + idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
 700         if (requested_pages > actual_pages)
 701                 return -EINVAL;
 702
 703         if (idev->info->mmap) {
 704                 ret = idev->info->mmap(idev->info, vma);
 705                 return ret;
 706         }
 707
 708         switch (idev->info->mem[mi].memtype) {
 709                 case UIO_MEM_PHYS:
 710                         return uio_mmap_physical(vma);
 711                 case UIO_MEM_LOGICAL:
 712                 case UIO_MEM_VIRTUAL:
 713                         return uio_mmap_logical(vma);
 714                 default:
 715                         return -EINVAL;
 716         }
 717 }
 718
 719 static const struct file_operations uio_fops = {
 720         .owner          = THIS_MODULE,
 721         .open           = uio_open,
 722         .release        = uio_release,
 723         .read           = uio_read,
 724         .write          = uio_write,
 725         .mmap           = uio_mmap,
 726         .poll           = uio_poll,
 727         .fasync         = uio_fasync,
 728         .llseek         = noop_llseek,
 729 };
 730
 731 static int uio_major_init(void)
 732 {
 733         static const char name[] = "uio";
 734         struct cdev *cdev = NULL;
 735         dev_t uio_dev = 0;
 736         int result;
 737
 738         result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name);
 739         if (result)
 740                 goto out;
 741
 742         result = -ENOMEM;
 743         cdev = cdev_alloc();
 744         if (!cdev)
 745                 goto out_unregister;
 746
 747         cdev->owner = THIS_MODULE;
 748         cdev->ops = &uio_fops;
 749         kobject_set_name(&cdev->kobj, "%s", name);
 750
 751         result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES);
 752         if (result)
 753                 goto out_put;
 754
 755         uio_major = MAJOR(uio_dev);
 756         uio_cdev = cdev;
 757         return 0;
 758 out_put:
 759         kobject_put(&cdev->kobj);
 760 out_unregister:
 761         unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
 762 out:
 763         return result;
 764 }
 765
 766 static void uio_major_cleanup(void)
 767 {
 768         unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
 769         cdev_del(uio_cdev);
 770 }
 771
 772 static int init_uio_class(void)
 773 {
 774         int ret;
 775
 776         /* This is the first time in here, set everything up properly */
 777         ret = uio_major_init();
 778         if (ret)
 779                 goto exit;
 780
 781         ret = class_register(&uio_class);
 782         if (ret) {
 783                 printk(KERN_ERR "class_register failed for uio\n");
 784                 goto err_class_register;
 785         }
 786         return 0;
 787
 788 err_class_register:
 789         uio_major_cleanup();
 790 exit:
 791         return ret;
 792 }
 793
 794 static void release_uio_class(void)
 795 {
 796         class_unregister(&uio_class);
 797         uio_major_cleanup();
 798 }
 799
 800 /**
 801  * uio_register_device - register a new userspace IO device
 802  * @owner:      module that creates the new device
 803  * @parent:     parent device
 804  * @info:       UIO device capabilities
 805  *
 806  * returns zero on success or a negative error code.
 807  */
 808 int __uio_register_device(struct module *owner,
 809                           struct device *parent,
 810                           struct uio_info *info)
 811 {
 812         struct uio_device *idev;
 813         int ret = 0;
 814
 815         if (!parent || !info || !info->name || !info->version)
 816                 return -EINVAL;
 817
 818         info->uio_dev = NULL;
 819
 820         idev = devm_kzalloc(parent, sizeof(*idev), GFP_KERNEL);
 821         if (!idev) {
 822                 return -ENOMEM;
 823         }
 824
 825         idev->owner = owner;
 826         idev->info = info;
 827         init_waitqueue_head(&idev->wait);
 828         atomic_set(&idev->event, 0);
 829
 830         ret = uio_get_minor(idev);
 831         if (ret)
 832                 return ret;
 833
 834         idev->dev = device_create(&uio_class, parent,
 835                                   MKDEV(uio_major, idev->minor), idev,
 836                                   "uio%d", idev->minor);
 837         if (IS_ERR(idev->dev)) {
 838                 printk(KERN_ERR "UIO: device register failed\n");
 839                 ret = PTR_ERR(idev->dev);
 840                 goto err_device_create;
 841         }
 842
 843         ret = uio_dev_add_attributes(idev);
 844         if (ret)
 845                 goto err_uio_dev_add_attributes;
 846
 847         info->uio_dev = idev;
 848
 849         if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) {
 850                 ret = devm_request_irq(idev->dev, info->irq, uio_interrupt,
 851                                   info->irq_flags, info->name, idev);
 852                 if (ret)
 853                         goto err_request_irq;
 854         }
 855
 856         return 0;
 857
 858 err_request_irq:
 859         uio_dev_del_attributes(idev);
 860 err_uio_dev_add_attributes:
 861         device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
 862 err_device_create:
 863         uio_free_minor(idev);
 864         return ret;
 865 }
 866 EXPORT_SYMBOL_GPL(__uio_register_device);
 867
 868 /**
 869  * uio_unregister_device - unregister a industrial IO device
 870  * @info:       UIO device capabilities
 871  *
 872  */
 873 void uio_unregister_device(struct uio_info *info)
 874 {
 875         struct uio_device *idev;
 876
 877         if (!info || !info->uio_dev)
 878                 return;
 879
 880         idev = info->uio_dev;
 881
 882         uio_free_minor(idev);
 883
 884         uio_dev_del_attributes(idev);
 885
 886         device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
 887
 888         return;
 889 }
 890 EXPORT_SYMBOL_GPL(uio_unregister_device);
 891
 892 static int __init uio_init(void)
 893 {
 894         return init_uio_class();
 895 }
 896
 897 static void __exit uio_exit(void)
 898 {
 899         release_uio_class();
 900 }
 901
 902 module_init(uio_init)
 903 module_exit(uio_exit)
 904 MODULE_LICENSE("GPL v2");