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 unsigned long flags; 437 438 mutex_lock(&minor_lock); 439 idev = idr_find(&uio_idr, iminor(inode)); 440 mutex_unlock(&minor_lock); 441 if (!idev) { 442 ret = -ENODEV; 443 goto out; 444 } 445 446 get_device(&idev->dev); 447 448 if (!try_module_get(idev->owner)) { 449 ret = -ENODEV; 450 goto err_module_get; 451 } 452 453 listener = kmalloc(sizeof(*listener), GFP_KERNEL); 454 if (!listener) { 455 ret = -ENOMEM; 456 goto err_alloc_listener; 457 } 458 459 listener->dev = idev; 460 listener->event_count = atomic_read(&idev->event); 461 filep->private_data = listener; 462 463 spin_lock_irqsave(&idev->info_lock, flags); 464 if (idev->info && idev->info->open) 465 ret = idev->info->open(idev->info, inode); 466 spin_unlock_irqrestore(&idev->info_lock, flags); 467 if (ret) 468 goto err_infoopen; 469 470 return 0; 471 472 err_infoopen: 473 kfree(listener); 474 475 err_alloc_listener: 476 module_put(idev->owner); 477 478 err_module_get: 479 put_device(&idev->dev); 480 481 out: 482 return ret; 483 } 484 485 static int uio_fasync(int fd, struct file *filep, int on) 486 { 487 struct uio_listener *listener = filep->private_data; 488 struct uio_device *idev = listener->dev; 489 490 return fasync_helper(fd, filep, on, &idev->async_queue); 491 } 492 493 static int uio_release(struct inode *inode, struct file *filep) 494 { 495 int ret = 0; 496 struct uio_listener *listener = filep->private_data; 497 struct uio_device *idev = listener->dev; 498 unsigned long flags; 499 500 spin_lock_irqsave(&idev->info_lock, flags); 501 if (idev->info && idev->info->release) 502 ret = idev->info->release(idev->info, inode); 503 spin_unlock_irqrestore(&idev->info_lock, flags); 504 505 module_put(idev->owner); 506 kfree(listener); 507 put_device(&idev->dev); 508 return ret; 509 } 510 511 static __poll_t uio_poll(struct file *filep, poll_table *wait) 512 { 513 struct uio_listener *listener = filep->private_data; 514 struct uio_device *idev = listener->dev; 515 __poll_t ret = 0; 516 unsigned long flags; 517 518 spin_lock_irqsave(&idev->info_lock, flags); 519 if (!idev->info || !idev->info->irq) 520 ret = -EIO; 521 spin_unlock_irqrestore(&idev->info_lock, flags); 522 523 if (ret) 524 return ret; 525 526 poll_wait(filep, &idev->wait, wait); 527 if (listener->event_count != atomic_read(&idev->event)) 528 return EPOLLIN | EPOLLRDNORM; 529 return 0; 530 } 531 532 static ssize_t uio_read(struct file *filep, char __user *buf, 533 size_t count, loff_t *ppos) 534 { 535 struct uio_listener *listener = filep->private_data; 536 struct uio_device *idev = listener->dev; 537 DECLARE_WAITQUEUE(wait, current); 538 ssize_t retval = 0; 539 s32 event_count; 540 unsigned long flags; 541 542 spin_lock_irqsave(&idev->info_lock, flags); 543 if (!idev->info || !idev->info->irq) 544 retval = -EIO; 545 spin_unlock_irqrestore(&idev->info_lock, flags); 546 547 if (retval) 548 return retval; 549 550 if (count != sizeof(s32)) 551 return -EINVAL; 552 553 add_wait_queue(&idev->wait, &wait); 554 555 do { 556 set_current_state(TASK_INTERRUPTIBLE); 557 558 event_count = atomic_read(&idev->event); 559 if (event_count != listener->event_count) { 560 __set_current_state(TASK_RUNNING); 561 if (copy_to_user(buf, &event_count, count)) 562 retval = -EFAULT; 563 else { 564 listener->event_count = event_count; 565 retval = count; 566 } 567 break; 568 } 569 570 if (filep->f_flags & O_NONBLOCK) { 571 retval = -EAGAIN; 572 break; 573 } 574 575 if (signal_pending(current)) { 576 retval = -ERESTARTSYS; 577 break; 578 } 579 schedule(); 580 } while (1); 581 582 __set_current_state(TASK_RUNNING); 583 remove_wait_queue(&idev->wait, &wait); 584 585 return retval; 586 } 587 588 static ssize_t uio_write(struct file *filep, const char __user *buf, 589 size_t count, loff_t *ppos) 590 { 591 struct uio_listener *listener = filep->private_data; 592 struct uio_device *idev = listener->dev; 593 ssize_t retval; 594 s32 irq_on; 595 unsigned long flags; 596 597 spin_lock_irqsave(&idev->info_lock, flags); 598 if (!idev->info || !idev->info->irq) { 599 retval = -EIO; 600 goto out; 601 } 602 603 if (count != sizeof(s32)) { 604 retval = -EINVAL; 605 goto out; 606 } 607 608 if (!idev->info->irqcontrol) { 609 retval = -ENOSYS; 610 goto out; 611 } 612 613 if (copy_from_user(&irq_on, buf, count)) { 614 retval = -EFAULT; 615 goto out; 616 } 617 618 retval = idev->info->irqcontrol(idev->info, irq_on); 619 620 out: 621 spin_unlock_irqrestore(&idev->info_lock, flags); 622 return retval ? retval : sizeof(s32); 623 } 624 625 static int uio_find_mem_index(struct vm_area_struct *vma) 626 { 627 struct uio_device *idev = vma->vm_private_data; 628 629 if (vma->vm_pgoff < MAX_UIO_MAPS) { 630 if (idev->info->mem[vma->vm_pgoff].size == 0) 631 return -1; 632 return (int)vma->vm_pgoff; 633 } 634 return -1; 635 } 636 637 static vm_fault_t uio_vma_fault(struct vm_fault *vmf) 638 { 639 struct uio_device *idev = vmf->vma->vm_private_data; 640 struct page *page; 641 unsigned long offset; 642 void *addr; 643 644 int mi = uio_find_mem_index(vmf->vma); 645 if (mi < 0) 646 return VM_FAULT_SIGBUS; 647 648 /* 649 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE 650 * to use mem[N]. 651 */ 652 offset = (vmf->pgoff - mi) << PAGE_SHIFT; 653 654 addr = (void *)(unsigned long)idev->info->mem[mi].addr + offset; 655 if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL) 656 page = virt_to_page(addr); 657 else 658 page = vmalloc_to_page(addr); 659 get_page(page); 660 vmf->page = page; 661 return 0; 662 } 663 664 static const struct vm_operations_struct uio_logical_vm_ops = { 665 .fault = uio_vma_fault, 666 }; 667 668 static int uio_mmap_logical(struct vm_area_struct *vma) 669 { 670 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 671 vma->vm_ops = &uio_logical_vm_ops; 672 return 0; 673 } 674 675 static const struct vm_operations_struct uio_physical_vm_ops = { 676 #ifdef CONFIG_HAVE_IOREMAP_PROT 677 .access = generic_access_phys, 678 #endif 679 }; 680 681 static int uio_mmap_physical(struct vm_area_struct *vma) 682 { 683 struct uio_device *idev = vma->vm_private_data; 684 int mi = uio_find_mem_index(vma); 685 struct uio_mem *mem; 686 if (mi < 0) 687 return -EINVAL; 688 mem = idev->info->mem + mi; 689 690 if (mem->addr & ~PAGE_MASK) 691 return -ENODEV; 692 if (vma->vm_end - vma->vm_start > mem->size) 693 return -EINVAL; 694 695 vma->vm_ops = &uio_physical_vm_ops; 696 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 697 698 /* 699 * We cannot use the vm_iomap_memory() helper here, 700 * because vma->vm_pgoff is the map index we looked 701 * up above in uio_find_mem_index(), rather than an 702 * actual page offset into the mmap. 703 * 704 * So we just do the physical mmap without a page 705 * offset. 706 */ 707 return remap_pfn_range(vma, 708 vma->vm_start, 709 mem->addr >> PAGE_SHIFT, 710 vma->vm_end - vma->vm_start, 711 vma->vm_page_prot); 712 } 713 714 static int uio_mmap(struct file *filep, struct vm_area_struct *vma) 715 { 716 struct uio_listener *listener = filep->private_data; 717 struct uio_device *idev = listener->dev; 718 int mi; 719 unsigned long requested_pages, actual_pages; 720 int ret = 0; 721 722 if (vma->vm_end < vma->vm_start) 723 return -EINVAL; 724 725 vma->vm_private_data = idev; 726 727 mi = uio_find_mem_index(vma); 728 if (mi < 0) 729 return -EINVAL; 730 731 requested_pages = vma_pages(vma); 732 actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK) 733 + idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT; 734 if (requested_pages > actual_pages) 735 return -EINVAL; 736 737 if (idev->info->mmap) { 738 ret = idev->info->mmap(idev->info, vma); 739 return ret; 740 } 741 742 switch (idev->info->mem[mi].memtype) { 743 case UIO_MEM_PHYS: 744 return uio_mmap_physical(vma); 745 case UIO_MEM_LOGICAL: 746 case UIO_MEM_VIRTUAL: 747 return uio_mmap_logical(vma); 748 default: 749 return -EINVAL; 750 } 751 } 752 753 static const struct file_operations uio_fops = { 754 .owner = THIS_MODULE, 755 .open = uio_open, 756 .release = uio_release, 757 .read = uio_read, 758 .write = uio_write, 759 .mmap = uio_mmap, 760 .poll = uio_poll, 761 .fasync = uio_fasync, 762 .llseek = noop_llseek, 763 }; 764 765 static int uio_major_init(void) 766 { 767 static const char name[] = "uio"; 768 struct cdev *cdev = NULL; 769 dev_t uio_dev = 0; 770 int result; 771 772 result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name); 773 if (result) 774 goto out; 775 776 result = -ENOMEM; 777 cdev = cdev_alloc(); 778 if (!cdev) 779 goto out_unregister; 780 781 cdev->owner = THIS_MODULE; 782 cdev->ops = &uio_fops; 783 kobject_set_name(&cdev->kobj, "%s", name); 784 785 result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES); 786 if (result) 787 goto out_put; 788 789 uio_major = MAJOR(uio_dev); 790 uio_cdev = cdev; 791 return 0; 792 out_put: 793 kobject_put(&cdev->kobj); 794 out_unregister: 795 unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES); 796 out: 797 return result; 798 } 799 800 static void uio_major_cleanup(void) 801 { 802 unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES); 803 cdev_del(uio_cdev); 804 } 805 806 static int init_uio_class(void) 807 { 808 int ret; 809 810 /* This is the first time in here, set everything up properly */ 811 ret = uio_major_init(); 812 if (ret) 813 goto exit; 814 815 ret = class_register(&uio_class); 816 if (ret) { 817 printk(KERN_ERR "class_register failed for uio\n"); 818 goto err_class_register; 819 } 820 return 0; 821 822 err_class_register: 823 uio_major_cleanup(); 824 exit: 825 return ret; 826 } 827 828 static void release_uio_class(void) 829 { 830 class_unregister(&uio_class); 831 uio_major_cleanup(); 832 } 833 834 static void uio_device_release(struct device *dev) 835 { 836 struct uio_device *idev = dev_get_drvdata(dev); 837 838 kfree(idev); 839 } 840 841 /** 842 * uio_register_device - register a new userspace IO device 843 * @owner: module that creates the new device 844 * @parent: parent device 845 * @info: UIO device capabilities 846 * 847 * returns zero on success or a negative error code. 848 */ 849 int __uio_register_device(struct module *owner, 850 struct device *parent, 851 struct uio_info *info) 852 { 853 struct uio_device *idev; 854 int ret = 0; 855 856 if (!parent || !info || !info->name || !info->version) 857 return -EINVAL; 858 859 info->uio_dev = NULL; 860 861 idev = kzalloc(sizeof(*idev), GFP_KERNEL); 862 if (!idev) { 863 return -ENOMEM; 864 } 865 866 idev->owner = owner; 867 idev->info = info; 868 spin_lock_init(&idev->info_lock); 869 init_waitqueue_head(&idev->wait); 870 atomic_set(&idev->event, 0); 871 872 ret = uio_get_minor(idev); 873 if (ret) 874 return ret; 875 876 idev->dev.devt = MKDEV(uio_major, idev->minor); 877 idev->dev.class = &uio_class; 878 idev->dev.parent = parent; 879 idev->dev.release = uio_device_release; 880 dev_set_drvdata(&idev->dev, idev); 881 882 ret = dev_set_name(&idev->dev, "uio%d", idev->minor); 883 if (ret) 884 goto err_device_create; 885 886 ret = device_register(&idev->dev); 887 if (ret) 888 goto err_device_create; 889 890 ret = uio_dev_add_attributes(idev); 891 if (ret) 892 goto err_uio_dev_add_attributes; 893 894 info->uio_dev = idev; 895 896 if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) { 897 /* 898 * Note that we deliberately don't use devm_request_irq 899 * here. The parent module can unregister the UIO device 900 * and call pci_disable_msi, which requires that this 901 * irq has been freed. However, the device may have open 902 * FDs at the time of unregister and therefore may not be 903 * freed until they are released. 904 */ 905 ret = request_irq(info->irq, uio_interrupt, 906 info->irq_flags, info->name, idev); 907 if (ret) 908 goto err_request_irq; 909 } 910 911 return 0; 912 913 err_request_irq: 914 uio_dev_del_attributes(idev); 915 err_uio_dev_add_attributes: 916 device_unregister(&idev->dev); 917 err_device_create: 918 uio_free_minor(idev); 919 return ret; 920 } 921 EXPORT_SYMBOL_GPL(__uio_register_device); 922 923 /** 924 * uio_unregister_device - unregister a industrial IO device 925 * @info: UIO device capabilities 926 * 927 */ 928 void uio_unregister_device(struct uio_info *info) 929 { 930 struct uio_device *idev; 931 unsigned long flags; 932 933 if (!info || !info->uio_dev) 934 return; 935 936 idev = info->uio_dev; 937 938 uio_free_minor(idev); 939 940 uio_dev_del_attributes(idev); 941 942 if (info->irq && info->irq != UIO_IRQ_CUSTOM) 943 free_irq(info->irq, idev); 944 945 spin_lock_irqsave(&idev->info_lock, flags); 946 idev->info = NULL; 947 spin_unlock_irqrestore(&idev->info_lock, flags); 948 949 device_unregister(&idev->dev); 950 951 return; 952 } 953 EXPORT_SYMBOL_GPL(uio_unregister_device); 954 955 static int __init uio_init(void) 956 { 957 return init_uio_class(); 958 } 959 960 static void __exit uio_exit(void) 961 { 962 release_uio_class(); 963 idr_destroy(&uio_idr); 964 } 965 966 module_init(uio_init) 967 module_exit(uio_exit) 968 MODULE_LICENSE("GPL v2"); 969