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/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         int                     vma_count;
  39         struct uio_info         *info;
  40         struct kobject          *map_dir;
  41         struct kobject          *portio_dir;
  42 };
  43
  44 static int uio_major;
  45 static struct cdev *uio_cdev;
  46 static DEFINE_IDR(uio_idr);
  47 static const struct file_operations uio_fops;
  48
  49 /* UIO class infrastructure */
  50 static struct class *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         return sprintf(buf, "%s\n", idev->info->name);
 235 }
 236 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 237
 238 static ssize_t show_version(struct device *dev,
 239                             struct device_attribute *attr, char *buf)
 240 {
 241         struct uio_device *idev = dev_get_drvdata(dev);
 242         return sprintf(buf, "%s\n", idev->info->version);
 243 }
 244 static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);
 245
 246 static ssize_t show_event(struct device *dev,
 247                           struct device_attribute *attr, char *buf)
 248 {
 249         struct uio_device *idev = dev_get_drvdata(dev);
 250         return sprintf(buf, "%u\n", (unsigned int)atomic_read(&idev->event));
 251 }
 252 static DEVICE_ATTR(event, S_IRUGO, show_event, NULL);
 253
 254 static struct attribute *uio_attrs[] = {
 255         &dev_attr_name.attr,
 256         &dev_attr_version.attr,
 257         &dev_attr_event.attr,
 258         NULL,
 259 };
 260
 261 static struct attribute_group uio_attr_grp = {
 262         .attrs = uio_attrs,
 263 };
 264
 265 /*
 266  * device functions
 267  */
 268 static int uio_dev_add_attributes(struct uio_device *idev)
 269 {
 270         int ret;
 271         int mi, pi;
 272         int map_found = 0;
 273         int portio_found = 0;
 274         struct uio_mem *mem;
 275         struct uio_map *map;
 276         struct uio_port *port;
 277         struct uio_portio *portio;
 278
 279         ret = sysfs_create_group(&idev->dev->kobj, &uio_attr_grp);
 280         if (ret)
 281                 goto err_group;
 282
 283         for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
 284                 mem = &idev->info->mem[mi];
 285                 if (mem->size == 0)
 286                         break;
 287                 if (!map_found) {
 288                         map_found = 1;
 289                         idev->map_dir = kobject_create_and_add("maps",
 290                                                         &idev->dev->kobj);
 291                         if (!idev->map_dir)
 292                                 goto err_map;
 293                 }
 294                 map = kzalloc(sizeof(*map), GFP_KERNEL);
 295                 if (!map)
 296                         goto err_map;
 297                 kobject_init(&map->kobj, &map_attr_type);
 298                 map->mem = mem;
 299                 mem->map = map;
 300                 ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
 301                 if (ret)
 302                         goto err_map;
 303                 ret = kobject_uevent(&map->kobj, KOBJ_ADD);
 304                 if (ret)
 305                         goto err_map;
 306         }
 307
 308         for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
 309                 port = &idev->info->port[pi];
 310                 if (port->size == 0)
 311                         break;
 312                 if (!portio_found) {
 313                         portio_found = 1;
 314                         idev->portio_dir = kobject_create_and_add("portio",
 315                                                         &idev->dev->kobj);
 316                         if (!idev->portio_dir)
 317                                 goto err_portio;
 318                 }
 319                 portio = kzalloc(sizeof(*portio), GFP_KERNEL);
 320                 if (!portio)
 321                         goto err_portio;
 322                 kobject_init(&portio->kobj, &portio_attr_type);
 323                 portio->port = port;
 324                 port->portio = portio;
 325                 ret = kobject_add(&portio->kobj, idev->portio_dir,
 326                                                         "port%d", pi);
 327                 if (ret)
 328                         goto err_portio;
 329                 ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
 330                 if (ret)
 331                         goto err_portio;
 332         }
 333
 334         return 0;
 335
 336 err_portio:
 337         for (pi--; pi >= 0; pi--) {
 338                 port = &idev->info->port[pi];
 339                 portio = port->portio;
 340                 kobject_put(&portio->kobj);
 341         }
 342         kobject_put(idev->portio_dir);
 343 err_map:
 344         for (mi--; mi>=0; mi--) {
 345                 mem = &idev->info->mem[mi];
 346                 map = mem->map;
 347                 kobject_put(&map->kobj);
 348         }
 349         kobject_put(idev->map_dir);
 350         sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
 351 err_group:
 352         dev_err(idev->dev, "error creating sysfs files (%d)\n", ret);
 353         return ret;
 354 }
 355
 356 static void uio_dev_del_attributes(struct uio_device *idev)
 357 {
 358         int i;
 359         struct uio_mem *mem;
 360         struct uio_port *port;
 361
 362         for (i = 0; i < MAX_UIO_MAPS; i++) {
 363                 mem = &idev->info->mem[i];
 364                 if (mem->size == 0)
 365                         break;
 366                 kobject_put(&mem->map->kobj);
 367         }
 368         kobject_put(idev->map_dir);
 369
 370         for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
 371                 port = &idev->info->port[i];
 372                 if (port->size == 0)
 373                         break;
 374                 kobject_put(&port->portio->kobj);
 375         }
 376         kobject_put(idev->portio_dir);
 377
 378         sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp);
 379 }
 380
 381 static int uio_get_minor(struct uio_device *idev)
 382 {
 383         int retval = -ENOMEM;
 384         int id;
 385
 386         mutex_lock(&minor_lock);
 387         if (idr_pre_get(&uio_idr, GFP_KERNEL) == 0)
 388                 goto exit;
 389
 390         retval = idr_get_new(&uio_idr, idev, &id);
 391         if (retval < 0) {
 392                 if (retval == -EAGAIN)
 393                         retval = -ENOMEM;
 394                 goto exit;
 395         }
 396         idev->minor = id & MAX_ID_MASK;
 397 exit:
 398         mutex_unlock(&minor_lock);
 399         return retval;
 400 }
 401
 402 static void uio_free_minor(struct uio_device *idev)
 403 {
 404         mutex_lock(&minor_lock);
 405         idr_remove(&uio_idr, idev->minor);
 406         mutex_unlock(&minor_lock);
 407 }
 408
 409 /**
 410  * uio_event_notify - trigger an interrupt event
 411  * @info: UIO device capabilities
 412  */
 413 void uio_event_notify(struct uio_info *info)
 414 {
 415         struct uio_device *idev = info->uio_dev;
 416
 417         atomic_inc(&idev->event);
 418         wake_up_interruptible(&idev->wait);
 419         kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
 420 }
 421 EXPORT_SYMBOL_GPL(uio_event_notify);
 422
 423 /**
 424  * uio_interrupt - hardware interrupt handler
 425  * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
 426  * @dev_id: Pointer to the devices uio_device structure
 427  */
 428 static irqreturn_t uio_interrupt(int irq, void *dev_id)
 429 {
 430         struct uio_device *idev = (struct uio_device *)dev_id;
 431         irqreturn_t ret = idev->info->handler(irq, idev->info);
 432
 433         if (ret == IRQ_HANDLED)
 434                 uio_event_notify(idev->info);
 435
 436         return ret;
 437 }
 438
 439 struct uio_listener {
 440         struct uio_device *dev;
 441         s32 event_count;
 442 };
 443
 444 static int uio_open(struct inode *inode, struct file *filep)
 445 {
 446         struct uio_device *idev;
 447         struct uio_listener *listener;
 448         int ret = 0;
 449
 450         mutex_lock(&minor_lock);
 451         idev = idr_find(&uio_idr, iminor(inode));
 452         mutex_unlock(&minor_lock);
 453         if (!idev) {
 454                 ret = -ENODEV;
 455                 goto out;
 456         }
 457
 458         if (!try_module_get(idev->owner)) {
 459                 ret = -ENODEV;
 460                 goto out;
 461         }
 462
 463         listener = kmalloc(sizeof(*listener), GFP_KERNEL);
 464         if (!listener) {
 465                 ret = -ENOMEM;
 466                 goto err_alloc_listener;
 467         }
 468
 469         listener->dev = idev;
 470         listener->event_count = atomic_read(&idev->event);
 471         filep->private_data = listener;
 472
 473         if (idev->info->open) {
 474                 ret = idev->info->open(idev->info, inode);
 475                 if (ret)
 476                         goto err_infoopen;
 477         }
 478         return 0;
 479
 480 err_infoopen:
 481         kfree(listener);
 482
 483 err_alloc_listener:
 484         module_put(idev->owner);
 485
 486 out:
 487         return ret;
 488 }
 489
 490 static int uio_fasync(int fd, struct file *filep, int on)
 491 {
 492         struct uio_listener *listener = filep->private_data;
 493         struct uio_device *idev = listener->dev;
 494
 495         return fasync_helper(fd, filep, on, &idev->async_queue);
 496 }
 497
 498 static int uio_release(struct inode *inode, struct file *filep)
 499 {
 500         int ret = 0;
 501         struct uio_listener *listener = filep->private_data;
 502         struct uio_device *idev = listener->dev;
 503
 504         if (idev->info->release)
 505                 ret = idev->info->release(idev->info, inode);
 506
 507         module_put(idev->owner);
 508         kfree(listener);
 509         return ret;
 510 }
 511
 512 static unsigned int uio_poll(struct file *filep, poll_table *wait)
 513 {
 514         struct uio_listener *listener = filep->private_data;
 515         struct uio_device *idev = listener->dev;
 516
 517         if (!idev->info->irq)
 518                 return -EIO;
 519
 520         poll_wait(filep, &idev->wait, wait);
 521         if (listener->event_count != atomic_read(&idev->event))
 522                 return POLLIN | POLLRDNORM;
 523         return 0;
 524 }
 525
 526 static ssize_t uio_read(struct file *filep, char __user *buf,
 527                         size_t count, loff_t *ppos)
 528 {
 529         struct uio_listener *listener = filep->private_data;
 530         struct uio_device *idev = listener->dev;
 531         DECLARE_WAITQUEUE(wait, current);
 532         ssize_t retval;
 533         s32 event_count;
 534
 535         if (!idev->info->irq)
 536                 return -EIO;
 537
 538         if (count != sizeof(s32))
 539                 return -EINVAL;
 540
 541         add_wait_queue(&idev->wait, &wait);
 542
 543         do {
 544                 set_current_state(TASK_INTERRUPTIBLE);
 545
 546                 event_count = atomic_read(&idev->event);
 547                 if (event_count != listener->event_count) {
 548                         if (copy_to_user(buf, &event_count, count))
 549                                 retval = -EFAULT;
 550                         else {
 551                                 listener->event_count = event_count;
 552                                 retval = count;
 553                         }
 554                         break;
 555                 }
 556
 557                 if (filep->f_flags & O_NONBLOCK) {
 558                         retval = -EAGAIN;
 559                         break;
 560                 }
 561
 562                 if (signal_pending(current)) {
 563                         retval = -ERESTARTSYS;
 564                         break;
 565                 }
 566                 schedule();
 567         } while (1);
 568
 569         __set_current_state(TASK_RUNNING);
 570         remove_wait_queue(&idev->wait, &wait);
 571
 572         return retval;
 573 }
 574
 575 static ssize_t uio_write(struct file *filep, const char __user *buf,
 576                         size_t count, loff_t *ppos)
 577 {
 578         struct uio_listener *listener = filep->private_data;
 579         struct uio_device *idev = listener->dev;
 580         ssize_t retval;
 581         s32 irq_on;
 582
 583         if (!idev->info->irq)
 584                 return -EIO;
 585
 586         if (count != sizeof(s32))
 587                 return -EINVAL;
 588
 589         if (!idev->info->irqcontrol)
 590                 return -ENOSYS;
 591
 592         if (copy_from_user(&irq_on, buf, count))
 593                 return -EFAULT;
 594
 595         retval = idev->info->irqcontrol(idev->info, irq_on);
 596
 597         return retval ? retval : sizeof(s32);
 598 }
 599
 600 static int uio_find_mem_index(struct vm_area_struct *vma)
 601 {
 602         int mi;
 603         struct uio_device *idev = vma->vm_private_data;
 604
 605         for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
 606                 if (idev->info->mem[mi].size == 0)
 607                         return -1;
 608                 if (vma->vm_pgoff == mi)
 609                         return mi;
 610         }
 611         return -1;
 612 }
 613
 614 static void uio_vma_open(struct vm_area_struct *vma)
 615 {
 616         struct uio_device *idev = vma->vm_private_data;
 617         idev->vma_count++;
 618 }
 619
 620 static void uio_vma_close(struct vm_area_struct *vma)
 621 {
 622         struct uio_device *idev = vma->vm_private_data;
 623         idev->vma_count--;
 624 }
 625
 626 static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 627 {
 628         struct uio_device *idev = vma->vm_private_data;
 629         struct page *page;
 630         unsigned long offset;
 631
 632         int mi = uio_find_mem_index(vma);
 633         if (mi < 0)
 634                 return VM_FAULT_SIGBUS;
 635
 636         /*
 637          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
 638          * to use mem[N].
 639          */
 640         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
 641
 642         if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
 643                 page = virt_to_page(idev->info->mem[mi].addr + offset);
 644         else
 645                 page = vmalloc_to_page((void *)idev->info->mem[mi].addr
 646                                                         + offset);
 647         get_page(page);
 648         vmf->page = page;
 649         return 0;
 650 }
 651
 652 static const struct vm_operations_struct uio_vm_ops = {
 653         .open = uio_vma_open,
 654         .close = uio_vma_close,
 655         .fault = uio_vma_fault,
 656 };
 657
 658 static int uio_mmap_physical(struct vm_area_struct *vma)
 659 {
 660         struct uio_device *idev = vma->vm_private_data;
 661         int mi = uio_find_mem_index(vma);
 662         if (mi < 0)
 663                 return -EINVAL;
 664
 665         vma->vm_flags |= VM_IO | VM_RESERVED;
 666
 667         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 668
 669         return remap_pfn_range(vma,
 670                                vma->vm_start,
 671                                idev->info->mem[mi].addr >> PAGE_SHIFT,
 672                                vma->vm_end - vma->vm_start,
 673                                vma->vm_page_prot);
 674 }
 675
 676 static int uio_mmap_logical(struct vm_area_struct *vma)
 677 {
 678         vma->vm_flags |= VM_RESERVED;
 679         vma->vm_ops = &uio_vm_ops;
 680         uio_vma_open(vma);
 681         return 0;
 682 }
 683
 684 static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
 685 {
 686         struct uio_listener *listener = filep->private_data;
 687         struct uio_device *idev = listener->dev;
 688         int mi;
 689         unsigned long requested_pages, actual_pages;
 690         int ret = 0;
 691
 692         if (vma->vm_end < vma->vm_start)
 693                 return -EINVAL;
 694
 695         vma->vm_private_data = idev;
 696
 697         mi = uio_find_mem_index(vma);
 698         if (mi < 0)
 699                 return -EINVAL;
 700
 701         requested_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 702         actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
 703                         + idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
 704         if (requested_pages > actual_pages)
 705                 return -EINVAL;
 706
 707         if (idev->info->mmap) {
 708                 ret = idev->info->mmap(idev->info, vma);
 709                 return ret;
 710         }
 711
 712         switch (idev->info->mem[mi].memtype) {
 713                 case UIO_MEM_PHYS:
 714                         return uio_mmap_physical(vma);
 715                 case UIO_MEM_LOGICAL:
 716                 case UIO_MEM_VIRTUAL:
 717                         return uio_mmap_logical(vma);
 718                 default:
 719                         return -EINVAL;
 720         }
 721 }
 722
 723 static const struct file_operations uio_fops = {
 724         .owner          = THIS_MODULE,
 725         .open           = uio_open,
 726         .release        = uio_release,
 727         .read           = uio_read,
 728         .write          = uio_write,
 729         .mmap           = uio_mmap,
 730         .poll           = uio_poll,
 731         .fasync         = uio_fasync,
 732 };
 733
 734 static int uio_major_init(void)
 735 {
 736         static const char name[] = "uio";
 737         struct cdev *cdev = NULL;
 738         dev_t uio_dev = 0;
 739         int result;
 740
 741         result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name);
 742         if (result)
 743                 goto out;
 744
 745         result = -ENOMEM;
 746         cdev = cdev_alloc();
 747         if (!cdev)
 748                 goto out_unregister;
 749
 750         cdev->owner = THIS_MODULE;
 751         cdev->ops = &uio_fops;
 752         kobject_set_name(&cdev->kobj, "%s", name);
 753
 754         result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES);
 755         if (result)
 756                 goto out_put;
 757
 758         uio_major = MAJOR(uio_dev);
 759         uio_cdev = cdev;
 760         result = 0;
 761 out:
 762         return result;
 763 out_put:
 764         kobject_put(&cdev->kobj);
 765 out_unregister:
 766         unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
 767         goto out;
 768 }
 769
 770 static void uio_major_cleanup(void)
 771 {
 772         unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
 773         cdev_del(uio_cdev);
 774 }
 775
 776 static int init_uio_class(void)
 777 {
 778         struct class *class;
 779         int ret;
 780
 781         /* This is the first time in here, set everything up properly */
 782         ret = uio_major_init();
 783         if (ret)
 784                 goto exit;
 785
 786         class = class_create(THIS_MODULE, "uio");
 787         if (IS_ERR(class)) {
 788                 ret = IS_ERR(class);
 789                 printk(KERN_ERR "class_create failed for uio\n");
 790                 goto err_class_create;
 791         }
 792         uio_class = class;
 793         return 0;
 794
 795 err_class_create:
 796         uio_major_cleanup();
 797 exit:
 798         return ret;
 799 }
 800
 801 static void release_uio_class(void)
 802 {
 803         /* Ok, we cheat as we know we only have one uio_class */
 804         class_destroy(uio_class);
 805         uio_class = NULL;
 806         uio_major_cleanup();
 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         idev = kzalloc(sizeof(*idev), GFP_KERNEL);
 830         if (!idev) {
 831                 ret = -ENOMEM;
 832                 goto err_kzalloc;
 833         }
 834
 835         idev->owner = owner;
 836         idev->info = info;
 837         init_waitqueue_head(&idev->wait);
 838         atomic_set(&idev->event, 0);
 839
 840         ret = uio_get_minor(idev);
 841         if (ret)
 842                 goto err_get_minor;
 843
 844         idev->dev = device_create(uio_class, parent,
 845                                   MKDEV(uio_major, idev->minor), idev,
 846                                   "uio%d", idev->minor);
 847         if (IS_ERR(idev->dev)) {
 848                 printk(KERN_ERR "UIO: device register failed\n");
 849                 ret = PTR_ERR(idev->dev);
 850                 goto err_device_create;
 851         }
 852
 853         ret = uio_dev_add_attributes(idev);
 854         if (ret)
 855                 goto err_uio_dev_add_attributes;
 856
 857         info->uio_dev = idev;
 858
 859         if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) {
 860                 ret = request_irq(info->irq, uio_interrupt,
 861                                   info->irq_flags, info->name, idev);
 862                 if (ret)
 863                         goto err_request_irq;
 864         }
 865
 866         return 0;
 867
 868 err_request_irq:
 869         uio_dev_del_attributes(idev);
 870 err_uio_dev_add_attributes:
 871         device_destroy(uio_class, MKDEV(uio_major, idev->minor));
 872 err_device_create:
 873         uio_free_minor(idev);
 874 err_get_minor:
 875         kfree(idev);
 876 err_kzalloc:
 877         return ret;
 878 }
 879 EXPORT_SYMBOL_GPL(__uio_register_device);
 880
 881 /**
 882  * uio_unregister_device - unregister a industrial IO device
 883  * @info:       UIO device capabilities
 884  *
 885  */
 886 void uio_unregister_device(struct uio_info *info)
 887 {
 888         struct uio_device *idev;
 889
 890         if (!info || !info->uio_dev)
 891                 return;
 892
 893         idev = info->uio_dev;
 894
 895         uio_free_minor(idev);
 896
 897         if (info->irq && (info->irq != UIO_IRQ_CUSTOM))
 898                 free_irq(info->irq, idev);
 899
 900         uio_dev_del_attributes(idev);
 901
 902         device_destroy(uio_class, MKDEV(uio_major, idev->minor));
 903         kfree(idev);
 904
 905         return;
 906 }
 907 EXPORT_SYMBOL_GPL(uio_unregister_device);
 908
 909 static int __init uio_init(void)
 910 {
 911         return init_uio_class();
 912 }
 913
 914 static void __exit uio_exit(void)
 915 {
 916         release_uio_class();
 917 }
 918
 919 module_init(uio_init)
 920 module_exit(uio_exit)
 921 MODULE_LICENSE("GPL v2");