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