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->offs); 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; 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_kobj; 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; 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_kobj; 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 __poll_t 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 EPOLLIN | EPOLLRDNORM; 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"); 914