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 show_name(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
 233 static ssize_t show_version(struct device *dev,
 234                             struct device_attribute *attr, char *buf)
 235 {
 236         struct uio_device *idev = dev_get_drvdata(dev);
 237         return sprintf(buf, "%s\n", idev->info->version);
 238 }
 239
 240 static ssize_t show_event(struct device *dev,
 241                           struct device_attribute *attr, char *buf)
 242 {
 243         struct uio_device *idev = dev_get_drvdata(dev);
 244         return sprintf(buf, "%u\n", (unsigned int)atomic_read(&idev->event));
 245 }
 246
 247 static struct device_attribute uio_class_attributes[] = {
 248         __ATTR(name, S_IRUGO, show_name, NULL),
 249         __ATTR(version, S_IRUGO, show_version, NULL),
 250         __ATTR(event, S_IRUGO, show_event, NULL),
 251         {}
 252 };
 253
 254 /* UIO class infrastructure */
 255 static struct class uio_class = {
 256         .name = "uio",
 257         .dev_attrs = uio_class_attributes,
 258 };
 259
 260 /*
 261  * device functions
 262  */
 263 static int uio_dev_add_attributes(struct uio_device *idev)
 264 {
 265         int ret;
 266         int mi, pi;
 267         int map_found = 0;
 268         int portio_found = 0;
 269         struct uio_mem *mem;
 270         struct uio_map *map;
 271         struct uio_port *port;
 272         struct uio_portio *portio;
 273
 274         for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
 275                 mem = &idev->info->mem[mi];
 276                 if (mem->size == 0)
 277                         break;
 278                 if (!map_found) {
 279                         map_found = 1;
 280                         idev->map_dir = kobject_create_and_add("maps",
 281                                                         &idev->dev->kobj);
 282                         if (!idev->map_dir)
 283                                 goto err_map;
 284                 }
 285                 map = kzalloc(sizeof(*map), GFP_KERNEL);
 286                 if (!map)
 287                         goto err_map;
 288                 kobject_init(&map->kobj, &map_attr_type);
 289                 map->mem = mem;
 290                 mem->map = map;
 291                 ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
 292                 if (ret)
 293                         goto err_map;
 294                 ret = kobject_uevent(&map->kobj, KOBJ_ADD);
 295                 if (ret)
 296                         goto err_map;
 297         }
 298
 299         for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
 300                 port = &idev->info->port[pi];
 301                 if (port->size == 0)
 302                         break;
 303                 if (!portio_found) {
 304                         portio_found = 1;
 305                         idev->portio_dir = kobject_create_and_add("portio",
 306                                                         &idev->dev->kobj);
 307                         if (!idev->portio_dir)
 308                                 goto err_portio;
 309                 }
 310                 portio = kzalloc(sizeof(*portio), GFP_KERNEL);
 311                 if (!portio)
 312                         goto err_portio;
 313                 kobject_init(&portio->kobj, &portio_attr_type);
 314                 portio->port = port;
 315                 port->portio = portio;
 316                 ret = kobject_add(&portio->kobj, idev->portio_dir,
 317                                                         "port%d", pi);
 318                 if (ret)
 319                         goto err_portio;
 320                 ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
 321                 if (ret)
 322                         goto err_portio;
 323         }
 324
 325         return 0;
 326
 327 err_portio:
 328         for (pi--; pi >= 0; pi--) {
 329                 port = &idev->info->port[pi];
 330                 portio = port->portio;
 331                 kobject_put(&portio->kobj);
 332         }
 333         kobject_put(idev->portio_dir);
 334 err_map:
 335         for (mi--; mi>=0; mi--) {
 336                 mem = &idev->info->mem[mi];
 337                 map = mem->map;
 338                 kobject_put(&map->kobj);
 339         }
 340         kobject_put(idev->map_dir);
 341         dev_err(idev->dev, "error creating sysfs files (%d)\n", ret);
 342         return ret;
 343 }
 344
 345 static void uio_dev_del_attributes(struct uio_device *idev)
 346 {
 347         int i;
 348         struct uio_mem *mem;
 349         struct uio_port *port;
 350
 351         for (i = 0; i < MAX_UIO_MAPS; i++) {
 352                 mem = &idev->info->mem[i];
 353                 if (mem->size == 0)
 354                         break;
 355                 kobject_put(&mem->map->kobj);
 356         }
 357         kobject_put(idev->map_dir);
 358
 359         for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
 360                 port = &idev->info->port[i];
 361                 if (port->size == 0)
 362                         break;
 363                 kobject_put(&port->portio->kobj);
 364         }
 365         kobject_put(idev->portio_dir);
 366 }
 367
 368 static int uio_get_minor(struct uio_device *idev)
 369 {
 370         int retval = -ENOMEM;
 371
 372         mutex_lock(&minor_lock);
 373         retval = idr_alloc(&uio_idr, idev, 0, UIO_MAX_DEVICES, GFP_KERNEL);
 374         if (retval >= 0) {
 375                 idev->minor = retval;
 376                 retval = 0;
 377         } else if (retval == -ENOSPC) {
 378                 dev_err(idev->dev, "too many uio devices\n");
 379                 retval = -EINVAL;
 380         }
 381         mutex_unlock(&minor_lock);
 382         return retval;
 383 }
 384
 385 static void uio_free_minor(struct uio_device *idev)
 386 {
 387         mutex_lock(&minor_lock);
 388         idr_remove(&uio_idr, idev->minor);
 389         mutex_unlock(&minor_lock);
 390 }
 391
 392 /**
 393  * uio_event_notify - trigger an interrupt event
 394  * @info: UIO device capabilities
 395  */
 396 void uio_event_notify(struct uio_info *info)
 397 {
 398         struct uio_device *idev = info->uio_dev;
 399
 400         atomic_inc(&idev->event);
 401         wake_up_interruptible(&idev->wait);
 402         kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
 403 }
 404 EXPORT_SYMBOL_GPL(uio_event_notify);
 405
 406 /**
 407  * uio_interrupt - hardware interrupt handler
 408  * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
 409  * @dev_id: Pointer to the devices uio_device structure
 410  */
 411 static irqreturn_t uio_interrupt(int irq, void *dev_id)
 412 {
 413         struct uio_device *idev = (struct uio_device *)dev_id;
 414         irqreturn_t ret = idev->info->handler(irq, idev->info);
 415
 416         if (ret == IRQ_HANDLED)
 417                 uio_event_notify(idev->info);
 418
 419         return ret;
 420 }
 421
 422 struct uio_listener {
 423         struct uio_device *dev;
 424         s32 event_count;
 425 };
 426
 427 static int uio_open(struct inode *inode, struct file *filep)
 428 {
 429         struct uio_device *idev;
 430         struct uio_listener *listener;
 431         int ret = 0;
 432
 433         mutex_lock(&minor_lock);
 434         idev = idr_find(&uio_idr, iminor(inode));
 435         mutex_unlock(&minor_lock);
 436         if (!idev) {
 437                 ret = -ENODEV;
 438                 goto out;
 439         }
 440
 441         if (!try_module_get(idev->owner)) {
 442                 ret = -ENODEV;
 443                 goto out;
 444         }
 445
 446         listener = kmalloc(sizeof(*listener), GFP_KERNEL);
 447         if (!listener) {
 448                 ret = -ENOMEM;
 449                 goto err_alloc_listener;
 450         }
 451
 452         listener->dev = idev;
 453         listener->event_count = atomic_read(&idev->event);
 454         filep->private_data = listener;
 455
 456         if (idev->info->open) {
 457                 ret = idev->info->open(idev->info, inode);
 458                 if (ret)
 459                         goto err_infoopen;
 460         }
 461         return 0;
 462
 463 err_infoopen:
 464         kfree(listener);
 465
 466 err_alloc_listener:
 467         module_put(idev->owner);
 468
 469 out:
 470         return ret;
 471 }
 472
 473 static int uio_fasync(int fd, struct file *filep, int on)
 474 {
 475         struct uio_listener *listener = filep->private_data;
 476         struct uio_device *idev = listener->dev;
 477
 478         return fasync_helper(fd, filep, on, &idev->async_queue);
 479 }
 480
 481 static int uio_release(struct inode *inode, struct file *filep)
 482 {
 483         int ret = 0;
 484         struct uio_listener *listener = filep->private_data;
 485         struct uio_device *idev = listener->dev;
 486
 487         if (idev->info->release)
 488                 ret = idev->info->release(idev->info, inode);
 489
 490         module_put(idev->owner);
 491         kfree(listener);
 492         return ret;
 493 }
 494
 495 static unsigned int uio_poll(struct file *filep, poll_table *wait)
 496 {
 497         struct uio_listener *listener = filep->private_data;
 498         struct uio_device *idev = listener->dev;
 499
 500         if (!idev->info->irq)
 501                 return -EIO;
 502
 503         poll_wait(filep, &idev->wait, wait);
 504         if (listener->event_count != atomic_read(&idev->event))
 505                 return POLLIN | POLLRDNORM;
 506         return 0;
 507 }
 508
 509 static ssize_t uio_read(struct file *filep, char __user *buf,
 510                         size_t count, loff_t *ppos)
 511 {
 512         struct uio_listener *listener = filep->private_data;
 513         struct uio_device *idev = listener->dev;
 514         DECLARE_WAITQUEUE(wait, current);
 515         ssize_t retval;
 516         s32 event_count;
 517
 518         if (!idev->info->irq)
 519                 return -EIO;
 520
 521         if (count != sizeof(s32))
 522                 return -EINVAL;
 523
 524         add_wait_queue(&idev->wait, &wait);
 525
 526         do {
 527                 set_current_state(TASK_INTERRUPTIBLE);
 528
 529                 event_count = atomic_read(&idev->event);
 530                 if (event_count != listener->event_count) {
 531                         if (copy_to_user(buf, &event_count, count))
 532                                 retval = -EFAULT;
 533                         else {
 534                                 listener->event_count = event_count;
 535                                 retval = count;
 536                         }
 537                         break;
 538                 }
 539
 540                 if (filep->f_flags & O_NONBLOCK) {
 541                         retval = -EAGAIN;
 542                         break;
 543                 }
 544
 545                 if (signal_pending(current)) {
 546                         retval = -ERESTARTSYS;
 547                         break;
 548                 }
 549                 schedule();
 550         } while (1);
 551
 552         __set_current_state(TASK_RUNNING);
 553         remove_wait_queue(&idev->wait, &wait);
 554
 555         return retval;
 556 }
 557
 558 static ssize_t uio_write(struct file *filep, const char __user *buf,
 559                         size_t count, loff_t *ppos)
 560 {
 561         struct uio_listener *listener = filep->private_data;
 562         struct uio_device *idev = listener->dev;
 563         ssize_t retval;
 564         s32 irq_on;
 565
 566         if (!idev->info->irq)
 567                 return -EIO;
 568
 569         if (count != sizeof(s32))
 570                 return -EINVAL;
 571
 572         if (!idev->info->irqcontrol)
 573                 return -ENOSYS;
 574
 575         if (copy_from_user(&irq_on, buf, count))
 576                 return -EFAULT;
 577
 578         retval = idev->info->irqcontrol(idev->info, irq_on);
 579
 580         return retval ? retval : sizeof(s32);
 581 }
 582
 583 static int uio_find_mem_index(struct vm_area_struct *vma)
 584 {
 585         struct uio_device *idev = vma->vm_private_data;
 586
 587         if (vma->vm_pgoff < MAX_UIO_MAPS) {
 588                 if (idev->info->mem[vma->vm_pgoff].size == 0)
 589                         return -1;
 590                 return (int)vma->vm_pgoff;
 591         }
 592         return -1;
 593 }
 594
 595 static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 596 {
 597         struct uio_device *idev = vma->vm_private_data;
 598         struct page *page;
 599         unsigned long offset;
 600
 601         int mi = uio_find_mem_index(vma);
 602         if (mi < 0)
 603                 return VM_FAULT_SIGBUS;
 604
 605         /*
 606          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
 607          * to use mem[N].
 608          */
 609         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
 610
 611         if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
 612                 page = virt_to_page(idev->info->mem[mi].addr + offset);
 613         else
 614                 page = vmalloc_to_page((void *)(unsigned long)idev->info->mem[mi].addr + offset);
 615         get_page(page);
 616         vmf->page = page;
 617         return 0;
 618 }
 619
 620 static const struct vm_operations_struct uio_logical_vm_ops = {
 621         .fault = uio_vma_fault,
 622 };
 623
 624 static int uio_mmap_logical(struct vm_area_struct *vma)
 625 {
 626         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
 627         vma->vm_ops = &uio_logical_vm_ops;
 628         return 0;
 629 }
 630
 631 static const struct vm_operations_struct uio_physical_vm_ops = {
 632 #ifdef CONFIG_HAVE_IOREMAP_PROT
 633         .access = generic_access_phys,
 634 #endif
 635 };
 636
 637 static int uio_mmap_physical(struct vm_area_struct *vma)
 638 {
 639         struct uio_device *idev = vma->vm_private_data;
 640         int mi = uio_find_mem_index(vma);
 641         if (mi < 0)
 642                 return -EINVAL;
 643
 644         vma->vm_ops = &uio_physical_vm_ops;
 645
 646         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 647
 648         return remap_pfn_range(vma,
 649                                vma->vm_start,
 650                                idev->info->mem[mi].addr >> PAGE_SHIFT,
 651                                vma->vm_end - vma->vm_start,
 652                                vma->vm_page_prot);
 653 }
 654
 655 static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
 656 {
 657         struct uio_listener *listener = filep->private_data;
 658         struct uio_device *idev = listener->dev;
 659         int mi;
 660         unsigned long requested_pages, actual_pages;
 661         int ret = 0;
 662
 663         if (vma->vm_end < vma->vm_start)
 664                 return -EINVAL;
 665
 666         vma->vm_private_data = idev;
 667
 668         mi = uio_find_mem_index(vma);
 669         if (mi < 0)
 670                 return -EINVAL;
 671
 672         requested_pages = vma_pages(vma);
 673         actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
 674                         + idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
 675         if (requested_pages > actual_pages)
 676                 return -EINVAL;
 677
 678         if (idev->info->mmap) {
 679                 ret = idev->info->mmap(idev->info, vma);
 680                 return ret;
 681         }
 682
 683         switch (idev->info->mem[mi].memtype) {
 684                 case UIO_MEM_PHYS:
 685                         return uio_mmap_physical(vma);
 686                 case UIO_MEM_LOGICAL:
 687                 case UIO_MEM_VIRTUAL:
 688                         return uio_mmap_logical(vma);
 689                 default:
 690                         return -EINVAL;
 691         }
 692 }
 693
 694 static const struct file_operations uio_fops = {
 695         .owner          = THIS_MODULE,
 696         .open           = uio_open,
 697         .release        = uio_release,
 698         .read           = uio_read,
 699         .write          = uio_write,
 700         .mmap           = uio_mmap,
 701         .poll           = uio_poll,
 702         .fasync         = uio_fasync,
 703         .llseek         = noop_llseek,
 704 };
 705
 706 static int uio_major_init(void)
 707 {
 708         static const char name[] = "uio";
 709         struct cdev *cdev = NULL;
 710         dev_t uio_dev = 0;
 711         int result;
 712
 713         result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name);
 714         if (result)
 715                 goto out;
 716
 717         result = -ENOMEM;
 718         cdev = cdev_alloc();
 719         if (!cdev)
 720                 goto out_unregister;
 721
 722         cdev->owner = THIS_MODULE;
 723         cdev->ops = &uio_fops;
 724         kobject_set_name(&cdev->kobj, "%s", name);
 725
 726         result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES);
 727         if (result)
 728                 goto out_put;
 729
 730         uio_major = MAJOR(uio_dev);
 731         uio_cdev = cdev;
 732         return 0;
 733 out_put:
 734         kobject_put(&cdev->kobj);
 735 out_unregister:
 736         unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
 737 out:
 738         return result;
 739 }
 740
 741 static void uio_major_cleanup(void)
 742 {
 743         unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
 744         cdev_del(uio_cdev);
 745 }
 746
 747 static int init_uio_class(void)
 748 {
 749         int ret;
 750
 751         /* This is the first time in here, set everything up properly */
 752         ret = uio_major_init();
 753         if (ret)
 754                 goto exit;
 755
 756         ret = class_register(&uio_class);
 757         if (ret) {
 758                 printk(KERN_ERR "class_register failed for uio\n");
 759                 goto err_class_register;
 760         }
 761         return 0;
 762
 763 err_class_register:
 764         uio_major_cleanup();
 765 exit:
 766         return ret;
 767 }
 768
 769 static void release_uio_class(void)
 770 {
 771         class_unregister(&uio_class);
 772         uio_major_cleanup();
 773 }
 774
 775 /**
 776  * uio_register_device - register a new userspace IO device
 777  * @owner:      module that creates the new device
 778  * @parent:     parent device
 779  * @info:       UIO device capabilities
 780  *
 781  * returns zero on success or a negative error code.
 782  */
 783 int __uio_register_device(struct module *owner,
 784                           struct device *parent,
 785                           struct uio_info *info)
 786 {
 787         struct uio_device *idev;
 788         int ret = 0;
 789
 790         if (!parent || !info || !info->name || !info->version)
 791                 return -EINVAL;
 792
 793         info->uio_dev = NULL;
 794
 795         idev = kzalloc(sizeof(*idev), GFP_KERNEL);
 796         if (!idev) {
 797                 ret = -ENOMEM;
 798                 goto err_kzalloc;
 799         }
 800
 801         idev->owner = owner;
 802         idev->info = info;
 803         init_waitqueue_head(&idev->wait);
 804         atomic_set(&idev->event, 0);
 805
 806         ret = uio_get_minor(idev);
 807         if (ret)
 808                 goto err_get_minor;
 809
 810         idev->dev = device_create(&uio_class, parent,
 811                                   MKDEV(uio_major, idev->minor), idev,
 812                                   "uio%d", idev->minor);
 813         if (IS_ERR(idev->dev)) {
 814                 printk(KERN_ERR "UIO: device register failed\n");
 815                 ret = PTR_ERR(idev->dev);
 816                 goto err_device_create;
 817         }
 818
 819         ret = uio_dev_add_attributes(idev);
 820         if (ret)
 821                 goto err_uio_dev_add_attributes;
 822
 823         info->uio_dev = idev;
 824
 825         if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) {
 826                 ret = request_irq(info->irq, uio_interrupt,
 827                                   info->irq_flags, info->name, idev);
 828                 if (ret)
 829                         goto err_request_irq;
 830         }
 831
 832         return 0;
 833
 834 err_request_irq:
 835         uio_dev_del_attributes(idev);
 836 err_uio_dev_add_attributes:
 837         device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
 838 err_device_create:
 839         uio_free_minor(idev);
 840 err_get_minor:
 841         kfree(idev);
 842 err_kzalloc:
 843         return ret;
 844 }
 845 EXPORT_SYMBOL_GPL(__uio_register_device);
 846
 847 /**
 848  * uio_unregister_device - unregister a industrial IO device
 849  * @info:       UIO device capabilities
 850  *
 851  */
 852 void uio_unregister_device(struct uio_info *info)
 853 {
 854         struct uio_device *idev;
 855
 856         if (!info || !info->uio_dev)
 857                 return;
 858
 859         idev = info->uio_dev;
 860
 861         uio_free_minor(idev);
 862
 863         if (info->irq && (info->irq != UIO_IRQ_CUSTOM))
 864                 free_irq(info->irq, idev);
 865
 866         uio_dev_del_attributes(idev);
 867
 868         device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
 869         kfree(idev);
 870
 871         return;
 872 }
 873 EXPORT_SYMBOL_GPL(uio_unregister_device);
 874
 875 static int __init uio_init(void)
 876 {
 877         return init_uio_class();
 878 }
 879
 880 static void __exit uio_exit(void)
 881 {
 882         release_uio_class();
 883 }
 884
 885 module_init(uio_init)
 886 module_exit(uio_exit)
 887 MODULE_LICENSE("GPL v2");