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