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