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