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@linutronix.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/mm.h>
  21 #include <linux/idr.h>
  22 #include <linux/string.h>
  23 #include <linux/kobject.h>
  24 #include <linux/uio_driver.h>
  25
  26 #define UIO_MAX_DEVICES 255
  27
  28 struct uio_device {
  29         struct module           *owner;
  30         struct device           *dev;
  31         int                     minor;
  32         atomic_t                event;
  33         struct fasync_struct    *async_queue;
  34         wait_queue_head_t       wait;
  35         int                     vma_count;
  36         struct uio_info         *info;
  37         struct kobject          *map_dir;
  38         struct kobject          *portio_dir;
  39 };
  40
  41 static int uio_major;
  42 static DEFINE_IDR(uio_idr);
  43 static const struct file_operations uio_fops;
  44
  45 /* UIO class infrastructure */
  46 static struct uio_class {
  47         struct kref kref;
  48         struct class *class;
  49 } *uio_class;
  50
  51 /* Protect idr accesses */
  52 static DEFINE_MUTEX(minor_lock);
  53
  54 /*
  55  * attributes
  56  */
  57
  58 struct uio_map {
  59         struct kobject kobj;
  60         struct uio_mem *mem;
  61 };
  62 #define to_map(map) container_of(map, struct uio_map, kobj)
  63
  64 static ssize_t map_name_show(struct uio_mem *mem, char *buf)
  65 {
  66         if (unlikely(!mem->name))
  67                 mem->name = "";
  68
  69         return sprintf(buf, "%s\n", mem->name);
  70 }
  71
  72 static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
  73 {
  74         return sprintf(buf, "0x%lx\n", mem->addr);
  75 }
  76
  77 static ssize_t map_size_show(struct uio_mem *mem, char *buf)
  78 {
  79         return sprintf(buf, "0x%lx\n", mem->size);
  80 }
  81
  82 static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
  83 {
  84         return sprintf(buf, "0x%lx\n", mem->addr & ~PAGE_MASK);
  85 }
  86
  87 struct map_sysfs_entry {
  88         struct attribute attr;
  89         ssize_t (*show)(struct uio_mem *, char *);
  90         ssize_t (*store)(struct uio_mem *, const char *, size_t);
  91 };
  92
  93 static struct map_sysfs_entry name_attribute =
  94         __ATTR(name, S_IRUGO, map_name_show, NULL);
  95 static struct map_sysfs_entry addr_attribute =
  96         __ATTR(addr, S_IRUGO, map_addr_show, NULL);
  97 static struct map_sysfs_entry size_attribute =
  98         __ATTR(size, S_IRUGO, map_size_show, NULL);
  99 static struct map_sysfs_entry offset_attribute =
 100         __ATTR(offset, S_IRUGO, map_offset_show, NULL);
 101
 102 static struct attribute *attrs[] = {
 103         &name_attribute.attr,
 104         &addr_attribute.attr,
 105         &size_attribute.attr,
 106         &offset_attribute.attr,
 107         NULL,   /* need to NULL terminate the list of attributes */
 108 };
 109
 110 static void map_release(struct kobject *kobj)
 111 {
 112         struct uio_map *map = to_map(kobj);
 113         kfree(map);
 114 }
 115
 116 static ssize_t map_type_show(struct kobject *kobj, struct attribute *attr,
 117                              char *buf)
 118 {
 119         struct uio_map *map = to_map(kobj);
 120         struct uio_mem *mem = map->mem;
 121         struct map_sysfs_entry *entry;
 122
 123         entry = container_of(attr, struct map_sysfs_entry, attr);
 124
 125         if (!entry->show)
 126                 return -EIO;
 127
 128         return entry->show(mem, buf);
 129 }
 130
 131 static struct sysfs_ops map_sysfs_ops = {
 132         .show = map_type_show,
 133 };
 134
 135 static struct kobj_type map_attr_type = {
 136         .release        = map_release,
 137         .sysfs_ops      = &map_sysfs_ops,
 138         .default_attrs  = attrs,
 139 };
 140
 141 struct uio_portio {
 142         struct kobject kobj;
 143         struct uio_port *port;
 144 };
 145 #define to_portio(portio) container_of(portio, struct uio_portio, kobj)
 146
 147 static ssize_t portio_name_show(struct uio_port *port, char *buf)
 148 {
 149         if (unlikely(!port->name))
 150                 port->name = "";
 151
 152         return sprintf(buf, "%s\n", port->name);
 153 }
 154
 155 static ssize_t portio_start_show(struct uio_port *port, char *buf)
 156 {
 157         return sprintf(buf, "0x%lx\n", port->start);
 158 }
 159
 160 static ssize_t portio_size_show(struct uio_port *port, char *buf)
 161 {
 162         return sprintf(buf, "0x%lx\n", port->size);
 163 }
 164
 165 static ssize_t portio_porttype_show(struct uio_port *port, char *buf)
 166 {
 167         const char *porttypes[] = {"none", "x86", "gpio", "other"};
 168
 169         if ((port->porttype < 0) || (port->porttype > UIO_PORT_OTHER))
 170                 return -EINVAL;
 171
 172         return sprintf(buf, "port_%s\n", porttypes[port->porttype]);
 173 }
 174
 175 struct portio_sysfs_entry {
 176         struct attribute attr;
 177         ssize_t (*show)(struct uio_port *, char *);
 178         ssize_t (*store)(struct uio_port *, const char *, size_t);
 179 };
 180
 181 static struct portio_sysfs_entry portio_name_attribute =
 182         __ATTR(name, S_IRUGO, portio_name_show, NULL);
 183 static struct portio_sysfs_entry portio_start_attribute =
 184         __ATTR(start, S_IRUGO, portio_start_show, NULL);
 185 static struct portio_sysfs_entry portio_size_attribute =
 186         __ATTR(size, S_IRUGO, portio_size_show, NULL);
 187 static struct portio_sysfs_entry portio_porttype_attribute =
 188         __ATTR(porttype, S_IRUGO, portio_porttype_show, NULL);
 189
 190 static struct attribute *portio_attrs[] = {
 191         &portio_name_attribute.attr,
 192         &portio_start_attribute.attr,
 193         &portio_size_attribute.attr,
 194         &portio_porttype_attribute.attr,
 195         NULL,
 196 };
 197
 198 static void portio_release(struct kobject *kobj)
 199 {
 200         struct uio_portio *portio = to_portio(kobj);
 201         kfree(portio);
 202 }
 203
 204 static ssize_t portio_type_show(struct kobject *kobj, struct attribute *attr,
 205                              char *buf)
 206 {
 207         struct uio_portio *portio = to_portio(kobj);
 208         struct uio_port *port = portio->port;
 209         struct portio_sysfs_entry *entry;
 210
 211         entry = container_of(attr, struct portio_sysfs_entry, attr);
 212
 213         if (!entry->show)
 214                 return -EIO;
 215
 216         return entry->show(port, buf);
 217 }
 218
 219 static struct sysfs_ops portio_sysfs_ops = {
 220         .show = portio_type_show,
 221 };
 222
 223 static struct kobj_type portio_attr_type = {
 224         .release        = portio_release,
 225         .sysfs_ops      = &portio_sysfs_ops,
 226         .default_attrs  = portio_attrs,
 227 };
 228
 229 static ssize_t show_name(struct device *dev,
 230                          struct device_attribute *attr, char *buf)
 231 {
 232         struct uio_device *idev = dev_get_drvdata(dev);
 233         if (idev)
 234                 return sprintf(buf, "%s\n", idev->info->name);
 235         else
 236                 return -ENODEV;
 237 }
 238 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 239
 240 static ssize_t show_version(struct device *dev,
 241                             struct device_attribute *attr, char *buf)
 242 {
 243         struct uio_device *idev = dev_get_drvdata(dev);
 244         if (idev)
 245                 return sprintf(buf, "%s\n", idev->info->version);
 246         else
 247                 return -ENODEV;
 248 }
 249 static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);
 250
 251 static ssize_t show_event(struct device *dev,
 252                           struct device_attribute *attr, char *buf)
 253 {
 254         struct uio_device *idev = dev_get_drvdata(dev);
 255         if (idev)
 256                 return sprintf(buf, "%u\n",
 257                                 (unsigned int)atomic_read(&idev->event));
 258         else
 259                 return -ENODEV;
 260 }
 261 static DEVICE_ATTR(event, S_IRUGO, show_event, NULL);
 262
 263 static struct attribute *uio_attrs[] = {
 264         &dev_attr_name.attr,
 265         &dev_attr_version.attr,
 266         &dev_attr_event.attr,
 267         NULL,
 268 };
 269
 270 static struct attribute_group uio_attr_grp = {
 271         .attrs = uio_attrs,
 272 };
 273
 274 /*
 275  * device functions
 276  */
 277 static int uio_dev_add_attributes(struct uio_device *idev)
 278 {
 279         int ret;
 280         int mi, pi;
 281         int map_found = 0;
 282         int portio_found = 0;
 283         struct uio_mem *mem;
 284         struct uio_map *map;
 285         struct uio_port *port;
 286         struct uio_portio *portio;
 287
 288         ret = sysfs_create_group(&idev->dev->kobj, &uio_attr_grp);
 289         if (ret)
 290                 goto err_group;
 291
 292         for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
 293                 mem = &idev->info->mem[mi];
 294                 if (mem->size == 0)
 295                         break;
 296                 if (!map_found) {
 297                         map_found = 1;
 298                         idev->map_dir = kobject_create_and_add("maps",
 299                                                         &idev->dev->kobj);
 300                         if (!idev->map_dir)
 301                                 goto err_map;
 302                 }
 303                 map = kzalloc(sizeof(*map), GFP_KERNEL);
 304                 if (!map)
 305                         goto err_map;
 306                 kobject_init(&map->kobj, &map_attr_type);
 307                 map->mem = mem;
 308                 mem->map = map;
 309                 ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
 310                 if (ret)
 311                         goto err_map;
 312                 ret = kobject_uevent(&map->kobj, KOBJ_ADD);
 313                 if (ret)
 314                         goto err_map;
 315         }
 316
 317         for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
 318                 port = &idev->info->port[pi];
 319                 if (port->size == 0)
 320                         break;
 321                 if (!portio_found) {
 322                         portio_found = 1;
 323                         idev->portio_dir = kobject_create_and_add("portio",
 324                                                         &idev->dev->kobj);
 325                         if (!idev->portio_dir)
 326                                 goto err_portio;
 327                 }
 328                 portio = kzalloc(sizeof(*portio), GFP_KERNEL);
 329                 if (!portio)
 330                         goto err_portio;
 331                 kobject_init(&portio->kobj, &portio_attr_type);
 332                 portio->port = port;
 333                 port->portio = portio;
 334                 ret = kobject_add(&portio->kobj, idev->portio_dir,
 335                                                         "port%d", pi);
 336                 if (ret)
 337                         goto err_portio;
 338                 ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
 339                 if (ret)
 340                         goto err_portio;
 341         }
 342
 343         return 0;
 344
 345 err_portio:
 346         for (pi--; pi >= 0; pi--) {
 347                 port = &idev->info->port[pi];
 348                 portio = port->portio;
 349                 kobject_put(&portio->kobj);
 350         }
 351         kobject_put(idev->portio_dir);
 352 err_map:
 353         for (mi--; mi>=0; mi--) {
 354                 mem = &idev->info->mem[mi];
 355                 map = mem->map;
 356                 kobject_put(&map->kobj);
 357         }
 358         kobject_put(idev->map_dir);
 359         sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
 360 err_group:
 361         dev_err(idev->dev, "error creating sysfs files (%d)\n", ret);
 362         return ret;
 363 }
 364
 365 static void uio_dev_del_attributes(struct uio_device *idev)
 366 {
 367         int i;
 368         struct uio_mem *mem;
 369         struct uio_port *port;
 370
 371         for (i = 0; i < MAX_UIO_MAPS; i++) {
 372                 mem = &idev->info->mem[i];
 373                 if (mem->size == 0)
 374                         break;
 375                 kobject_put(&mem->map->kobj);
 376         }
 377         kobject_put(idev->map_dir);
 378
 379         for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
 380                 port = &idev->info->port[i];
 381                 if (port->size == 0)
 382                         break;
 383                 kobject_put(&port->portio->kobj);
 384         }
 385         kobject_put(idev->portio_dir);
 386
 387         sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
 388 }
 389
 390 static int uio_get_minor(struct uio_device *idev)
 391 {
 392         int retval = -ENOMEM;
 393         int id;
 394
 395         mutex_lock(&minor_lock);
 396         if (idr_pre_get(&uio_idr, GFP_KERNEL) == 0)
 397                 goto exit;
 398
 399         retval = idr_get_new(&uio_idr, idev, &id);
 400         if (retval < 0) {
 401                 if (retval == -EAGAIN)
 402                         retval = -ENOMEM;
 403                 goto exit;
 404         }
 405         idev->minor = id & MAX_ID_MASK;
 406 exit:
 407         mutex_unlock(&minor_lock);
 408         return retval;
 409 }
 410
 411 static void uio_free_minor(struct uio_device *idev)
 412 {
 413         mutex_lock(&minor_lock);
 414         idr_remove(&uio_idr, idev->minor);
 415         mutex_unlock(&minor_lock);
 416 }
 417
 418 /**
 419  * uio_event_notify - trigger an interrupt event
 420  * @info: UIO device capabilities
 421  */
 422 void uio_event_notify(struct uio_info *info)
 423 {
 424         struct uio_device *idev = info->uio_dev;
 425
 426         atomic_inc(&idev->event);
 427         wake_up_interruptible(&idev->wait);
 428         kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
 429 }
 430 EXPORT_SYMBOL_GPL(uio_event_notify);
 431
 432 /**
 433  * uio_interrupt - hardware interrupt handler
 434  * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
 435  * @dev_id: Pointer to the devices uio_device structure
 436  */
 437 static irqreturn_t uio_interrupt(int irq, void *dev_id)
 438 {
 439         struct uio_device *idev = (struct uio_device *)dev_id;
 440         irqreturn_t ret = idev->info->handler(irq, idev->info);
 441
 442         if (ret == IRQ_HANDLED)
 443                 uio_event_notify(idev->info);
 444
 445         return ret;
 446 }
 447
 448 struct uio_listener {
 449         struct uio_device *dev;
 450         s32 event_count;
 451 };
 452
 453 static int uio_open(struct inode *inode, struct file *filep)
 454 {
 455         struct uio_device *idev;
 456         struct uio_listener *listener;
 457         int ret = 0;
 458
 459         mutex_lock(&minor_lock);
 460         idev = idr_find(&uio_idr, iminor(inode));
 461         mutex_unlock(&minor_lock);
 462         if (!idev) {
 463                 ret = -ENODEV;
 464                 goto out;
 465         }
 466
 467         if (!try_module_get(idev->owner)) {
 468                 ret = -ENODEV;
 469                 goto out;
 470         }
 471
 472         listener = kmalloc(sizeof(*listener), GFP_KERNEL);
 473         if (!listener) {
 474                 ret = -ENOMEM;
 475                 goto err_alloc_listener;
 476         }
 477
 478         listener->dev = idev;
 479         listener->event_count = atomic_read(&idev->event);
 480         filep->private_data = listener;
 481
 482         if (idev->info->open) {
 483                 ret = idev->info->open(idev->info, inode);
 484                 if (ret)
 485                         goto err_infoopen;
 486         }
 487         return 0;
 488
 489 err_infoopen:
 490         kfree(listener);
 491
 492 err_alloc_listener:
 493         module_put(idev->owner);
 494
 495 out:
 496         return ret;
 497 }
 498
 499 static int uio_fasync(int fd, struct file *filep, int on)
 500 {
 501         struct uio_listener *listener = filep->private_data;
 502         struct uio_device *idev = listener->dev;
 503
 504         return fasync_helper(fd, filep, on, &idev->async_queue);
 505 }
 506
 507 static int uio_release(struct inode *inode, struct file *filep)
 508 {
 509         int ret = 0;
 510         struct uio_listener *listener = filep->private_data;
 511         struct uio_device *idev = listener->dev;
 512
 513         if (idev->info->release)
 514                 ret = idev->info->release(idev->info, inode);
 515
 516         module_put(idev->owner);
 517         kfree(listener);
 518         return ret;
 519 }
 520
 521 static unsigned int uio_poll(struct file *filep, poll_table *wait)
 522 {
 523         struct uio_listener *listener = filep->private_data;
 524         struct uio_device *idev = listener->dev;
 525
 526         if (idev->info->irq == UIO_IRQ_NONE)
 527                 return -EIO;
 528
 529         poll_wait(filep, &idev->wait, wait);
 530         if (listener->event_count != atomic_read(&idev->event))
 531                 return POLLIN | POLLRDNORM;
 532         return 0;
 533 }
 534
 535 static ssize_t uio_read(struct file *filep, char __user *buf,
 536                         size_t count, loff_t *ppos)
 537 {
 538         struct uio_listener *listener = filep->private_data;
 539         struct uio_device *idev = listener->dev;
 540         DECLARE_WAITQUEUE(wait, current);
 541         ssize_t retval;
 542         s32 event_count;
 543
 544         if (idev->info->irq == UIO_IRQ_NONE)
 545                 return -EIO;
 546
 547         if (count != sizeof(s32))
 548                 return -EINVAL;
 549
 550         add_wait_queue(&idev->wait, &wait);
 551
 552         do {
 553                 set_current_state(TASK_INTERRUPTIBLE);
 554
 555                 event_count = atomic_read(&idev->event);
 556                 if (event_count != listener->event_count) {
 557                         if (copy_to_user(buf, &event_count, count))
 558                                 retval = -EFAULT;
 559                         else {
 560                                 listener->event_count = event_count;
 561                                 retval = count;
 562                         }
 563                         break;
 564                 }
 565
 566                 if (filep->f_flags & O_NONBLOCK) {
 567                         retval = -EAGAIN;
 568                         break;
 569                 }
 570
 571                 if (signal_pending(current)) {
 572                         retval = -ERESTARTSYS;
 573                         break;
 574                 }
 575                 schedule();
 576         } while (1);
 577
 578         __set_current_state(TASK_RUNNING);
 579         remove_wait_queue(&idev->wait, &wait);
 580
 581         return retval;
 582 }
 583
 584 static ssize_t uio_write(struct file *filep, const char __user *buf,
 585                         size_t count, loff_t *ppos)
 586 {
 587         struct uio_listener *listener = filep->private_data;
 588         struct uio_device *idev = listener->dev;
 589         ssize_t retval;
 590         s32 irq_on;
 591
 592         if (idev->info->irq == UIO_IRQ_NONE)
 593                 return -EIO;
 594
 595         if (count != sizeof(s32))
 596                 return -EINVAL;
 597
 598         if (!idev->info->irqcontrol)
 599                 return -ENOSYS;
 600
 601         if (copy_from_user(&irq_on, buf, count))
 602                 return -EFAULT;
 603
 604         retval = idev->info->irqcontrol(idev->info, irq_on);
 605
 606         return retval ? retval : sizeof(s32);
 607 }
 608
 609 static int uio_find_mem_index(struct vm_area_struct *vma)
 610 {
 611         int mi;
 612         struct uio_device *idev = vma->vm_private_data;
 613
 614         for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
 615                 if (idev->info->mem[mi].size == 0)
 616                         return -1;
 617                 if (vma->vm_pgoff == mi)
 618                         return mi;
 619         }
 620         return -1;
 621 }
 622
 623 static void uio_vma_open(struct vm_area_struct *vma)
 624 {
 625         struct uio_device *idev = vma->vm_private_data;
 626         idev->vma_count++;
 627 }
 628
 629 static void uio_vma_close(struct vm_area_struct *vma)
 630 {
 631         struct uio_device *idev = vma->vm_private_data;
 632         idev->vma_count--;
 633 }
 634
 635 static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 636 {
 637         struct uio_device *idev = vma->vm_private_data;
 638         struct page *page;
 639         unsigned long offset;
 640
 641         int mi = uio_find_mem_index(vma);
 642         if (mi < 0)
 643                 return VM_FAULT_SIGBUS;
 644
 645         /*
 646          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
 647          * to use mem[N].
 648          */
 649         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
 650
 651         if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
 652                 page = virt_to_page(idev->info->mem[mi].addr + offset);
 653         else
 654                 page = vmalloc_to_page((void *)idev->info->mem[mi].addr
 655                                                         + offset);
 656         get_page(page);
 657         vmf->page = page;
 658         return 0;
 659 }
 660
 661 static struct vm_operations_struct uio_vm_ops = {
 662         .open = uio_vma_open,
 663         .close = uio_vma_close,
 664         .fault = uio_vma_fault,
 665 };
 666
 667 static int uio_mmap_physical(struct vm_area_struct *vma)
 668 {
 669         struct uio_device *idev = vma->vm_private_data;
 670         int mi = uio_find_mem_index(vma);
 671         if (mi < 0)
 672                 return -EINVAL;
 673
 674         vma->vm_flags |= VM_IO | VM_RESERVED;
 675
 676         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 677
 678         return remap_pfn_range(vma,
 679                                vma->vm_start,
 680                                idev->info->mem[mi].addr >> PAGE_SHIFT,
 681                                vma->vm_end - vma->vm_start,
 682                                vma->vm_page_prot);
 683 }
 684
 685 static int uio_mmap_logical(struct vm_area_struct *vma)
 686 {
 687         vma->vm_flags |= VM_RESERVED;
 688         vma->vm_ops = &uio_vm_ops;
 689         uio_vma_open(vma);
 690         return 0;
 691 }
 692
 693 static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
 694 {
 695         struct uio_listener *listener = filep->private_data;
 696         struct uio_device *idev = listener->dev;
 697         int mi;
 698         unsigned long requested_pages, actual_pages;
 699         int ret = 0;
 700
 701         if (vma->vm_end < vma->vm_start)
 702                 return -EINVAL;
 703
 704         vma->vm_private_data = idev;
 705
 706         mi = uio_find_mem_index(vma);
 707         if (mi < 0)
 708                 return -EINVAL;
 709
 710         requested_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 711         actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
 712                         + idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
 713         if (requested_pages > actual_pages)
 714                 return -EINVAL;
 715
 716         if (idev->info->mmap) {
 717                 ret = idev->info->mmap(idev->info, vma);
 718                 return ret;
 719         }
 720
 721         switch (idev->info->mem[mi].memtype) {
 722                 case UIO_MEM_PHYS:
 723                         return uio_mmap_physical(vma);
 724                 case UIO_MEM_LOGICAL:
 725                 case UIO_MEM_VIRTUAL:
 726                         return uio_mmap_logical(vma);
 727                 default:
 728                         return -EINVAL;
 729         }
 730 }
 731
 732 static const struct file_operations uio_fops = {
 733         .owner          = THIS_MODULE,
 734         .open           = uio_open,
 735         .release        = uio_release,
 736         .read           = uio_read,
 737         .write          = uio_write,
 738         .mmap           = uio_mmap,
 739         .poll           = uio_poll,
 740         .fasync         = uio_fasync,
 741 };
 742
 743 static int uio_major_init(void)
 744 {
 745         uio_major = register_chrdev(0, "uio", &uio_fops);
 746         if (uio_major < 0)
 747                 return uio_major;
 748         return 0;
 749 }
 750
 751 static void uio_major_cleanup(void)
 752 {
 753         unregister_chrdev(uio_major, "uio");
 754 }
 755
 756 static int init_uio_class(void)
 757 {
 758         int ret = 0;
 759
 760         if (uio_class != NULL) {
 761                 kref_get(&uio_class->kref);
 762                 goto exit;
 763         }
 764
 765         /* This is the first time in here, set everything up properly */
 766         ret = uio_major_init();
 767         if (ret)
 768                 goto exit;
 769
 770         uio_class = kzalloc(sizeof(*uio_class), GFP_KERNEL);
 771         if (!uio_class) {
 772                 ret = -ENOMEM;
 773                 goto err_kzalloc;
 774         }
 775
 776         kref_init(&uio_class->kref);
 777         uio_class->class = class_create(THIS_MODULE, "uio");
 778         if (IS_ERR(uio_class->class)) {
 779                 ret = IS_ERR(uio_class->class);
 780                 printk(KERN_ERR "class_create failed for uio\n");
 781                 goto err_class_create;
 782         }
 783         return 0;
 784
 785 err_class_create:
 786         kfree(uio_class);
 787         uio_class = NULL;
 788 err_kzalloc:
 789         uio_major_cleanup();
 790 exit:
 791         return ret;
 792 }
 793
 794 static void release_uio_class(struct kref *kref)
 795 {
 796         /* Ok, we cheat as we know we only have one uio_class */
 797         class_destroy(uio_class->class);
 798         kfree(uio_class);
 799         uio_major_cleanup();
 800         uio_class = NULL;
 801 }
 802
 803 static void uio_class_destroy(void)
 804 {
 805         if (uio_class)
 806                 kref_put(&uio_class->kref, release_uio_class);
 807 }
 808
 809 /**
 810  * uio_register_device - register a new userspace IO device
 811  * @owner:      module that creates the new device
 812  * @parent:     parent device
 813  * @info:       UIO device capabilities
 814  *
 815  * returns zero on success or a negative error code.
 816  */
 817 int __uio_register_device(struct module *owner,
 818                           struct device *parent,
 819                           struct uio_info *info)
 820 {
 821         struct uio_device *idev;
 822         int ret = 0;
 823
 824         if (!parent || !info || !info->name || !info->version)
 825                 return -EINVAL;
 826
 827         info->uio_dev = NULL;
 828
 829         ret = init_uio_class();
 830         if (ret)
 831                 return ret;
 832
 833         idev = kzalloc(sizeof(*idev), GFP_KERNEL);
 834         if (!idev) {
 835                 ret = -ENOMEM;
 836                 goto err_kzalloc;
 837         }
 838
 839         idev->owner = owner;
 840         idev->info = info;
 841         init_waitqueue_head(&idev->wait);
 842         atomic_set(&idev->event, 0);
 843
 844         ret = uio_get_minor(idev);
 845         if (ret)
 846                 goto err_get_minor;
 847
 848         idev->dev = device_create(uio_class->class, parent,
 849                                   MKDEV(uio_major, idev->minor), idev,
 850                                   "uio%d", idev->minor);
 851         if (IS_ERR(idev->dev)) {
 852                 printk(KERN_ERR "UIO: device register failed\n");
 853                 ret = PTR_ERR(idev->dev);
 854                 goto err_device_create;
 855         }
 856
 857         ret = uio_dev_add_attributes(idev);
 858         if (ret)
 859                 goto err_uio_dev_add_attributes;
 860
 861         info->uio_dev = idev;
 862
 863         if (idev->info->irq >= 0) {
 864                 ret = request_irq(idev->info->irq, uio_interrupt,
 865                                   idev->info->irq_flags, idev->info->name, idev);
 866                 if (ret)
 867                         goto err_request_irq;
 868         }
 869
 870         return 0;
 871
 872 err_request_irq:
 873         uio_dev_del_attributes(idev);
 874 err_uio_dev_add_attributes:
 875         device_destroy(uio_class->class, MKDEV(uio_major, idev->minor));
 876 err_device_create:
 877         uio_free_minor(idev);
 878 err_get_minor:
 879         kfree(idev);
 880 err_kzalloc:
 881         uio_class_destroy();
 882         return ret;
 883 }
 884 EXPORT_SYMBOL_GPL(__uio_register_device);
 885
 886 /**
 887  * uio_unregister_device - unregister a industrial IO device
 888  * @info:       UIO device capabilities
 889  *
 890  */
 891 void uio_unregister_device(struct uio_info *info)
 892 {
 893         struct uio_device *idev;
 894
 895         if (!info || !info->uio_dev)
 896                 return;
 897
 898         idev = info->uio_dev;
 899
 900         uio_free_minor(idev);
 901
 902         if (info->irq >= 0)
 903                 free_irq(info->irq, idev);
 904
 905         uio_dev_del_attributes(idev);
 906
 907         dev_set_drvdata(idev->dev, NULL);
 908         device_destroy(uio_class->class, MKDEV(uio_major, idev->minor));
 909         kfree(idev);
 910         uio_class_destroy();
 911
 912         return;
 913 }
 914 EXPORT_SYMBOL_GPL(uio_unregister_device);
 915
 916 static int __init uio_init(void)
 917 {
 918         return 0;
 919 }
 920
 921 static void __exit uio_exit(void)
 922 {
 923 }
 924
 925 module_init(uio_init)
 926 module_exit(uio_exit)
 927 MODULE_LICENSE("GPL v2");