1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * drivers/uio/uio.c 4 * 5 * Copyright(C) 2005, Benedikt Spranger <b.spranger@linutronix.de> 6 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de> 7 * Copyright(C) 2006, Hans J. Koch <hjk@hansjkoch.de> 8 * Copyright(C) 2006, Greg Kroah-Hartman <greg@kroah.com> 9 * 10 * Userspace IO 11 * 12 * Base Functions 13 */ 14 15 #include <linux/module.h> 16 #include <linux/init.h> 17 #include <linux/poll.h> 18 #include <linux/device.h> 19 #include <linux/slab.h> 20 #include <linux/mm.h> 21 #include <linux/idr.h> 22 #include <linux/sched/signal.h> 23 #include <linux/string.h> 24 #include <linux/kobject.h> 25 #include <linux/cdev.h> 26 #include <linux/uio_driver.h> 27 28 #define UIO_MAX_DEVICES (1U << MINORBITS) 29 30 static int uio_major; 31 static struct cdev *uio_cdev; 32 static DEFINE_IDR(uio_idr); 33 static const struct file_operations uio_fops; 34 35 /* Protect idr accesses */ 36 static DEFINE_MUTEX(minor_lock); 37 38 /* 39 * attributes 40 */ 41 42 struct uio_map { 43 struct kobject kobj; 44 struct uio_mem *mem; 45 }; 46 #define to_map(map) container_of(map, struct uio_map, kobj) 47 48 static ssize_t map_name_show(struct uio_mem *mem, char *buf) 49 { 50 if (unlikely(!mem->name)) 51 mem->name = ""; 52 53 return sprintf(buf, "%s\n", mem->name); 54 } 55 56 static ssize_t map_addr_show(struct uio_mem *mem, char *buf) 57 { 58 return sprintf(buf, "%pa\n", &mem->addr); 59 } 60 61 static ssize_t map_size_show(struct uio_mem *mem, char *buf) 62 { 63 return sprintf(buf, "%pa\n", &mem->size); 64 } 65 66 static ssize_t map_offset_show(struct uio_mem *mem, char *buf) 67 { 68 return sprintf(buf, "0x%llx\n", (unsigned long long)mem->offs); 69 } 70 71 struct map_sysfs_entry { 72 struct attribute attr; 73 ssize_t (*show)(struct uio_mem *, char *); 74 ssize_t (*store)(struct uio_mem *, const char *, size_t); 75 }; 76 77 static struct map_sysfs_entry name_attribute = 78 __ATTR(name, S_IRUGO, map_name_show, NULL); 79 static struct map_sysfs_entry addr_attribute = 80 __ATTR(addr, S_IRUGO, map_addr_show, NULL); 81 static struct map_sysfs_entry size_attribute = 82 __ATTR(size, S_IRUGO, map_size_show, NULL); 83 static struct map_sysfs_entry offset_attribute = 84 __ATTR(offset, S_IRUGO, map_offset_show, NULL); 85 86 static struct attribute *attrs[] = { 87 &name_attribute.attr, 88 &addr_attribute.attr, 89 &size_attribute.attr, 90 &offset_attribute.attr, 91 NULL, /* need to NULL terminate the list of attributes */ 92 }; 93 94 static void map_release(struct kobject *kobj) 95 { 96 struct uio_map *map = to_map(kobj); 97 kfree(map); 98 } 99 100 static ssize_t map_type_show(struct kobject *kobj, struct attribute *attr, 101 char *buf) 102 { 103 struct uio_map *map = to_map(kobj); 104 struct uio_mem *mem = map->mem; 105 struct map_sysfs_entry *entry; 106 107 entry = container_of(attr, struct map_sysfs_entry, attr); 108 109 if (!entry->show) 110 return -EIO; 111 112 return entry->show(mem, buf); 113 } 114 115 static const struct sysfs_ops map_sysfs_ops = { 116 .show = map_type_show, 117 }; 118 119 static struct kobj_type map_attr_type = { 120 .release = map_release, 121 .sysfs_ops = &map_sysfs_ops, 122 .default_attrs = attrs, 123 }; 124 125 struct uio_portio { 126 struct kobject kobj; 127 struct uio_port *port; 128 }; 129 #define to_portio(portio) container_of(portio, struct uio_portio, kobj) 130 131 static ssize_t portio_name_show(struct uio_port *port, char *buf) 132 { 133 if (unlikely(!port->name)) 134 port->name = ""; 135 136 return sprintf(buf, "%s\n", port->name); 137 } 138 139 static ssize_t portio_start_show(struct uio_port *port, char *buf) 140 { 141 return sprintf(buf, "0x%lx\n", port->start); 142 } 143 144 static ssize_t portio_size_show(struct uio_port *port, char *buf) 145 { 146 return sprintf(buf, "0x%lx\n", port->size); 147 } 148 149 static ssize_t portio_porttype_show(struct uio_port *port, char *buf) 150 { 151 const char *porttypes[] = {"none", "x86", "gpio", "other"}; 152 153 if ((port->porttype < 0) || (port->porttype > UIO_PORT_OTHER)) 154 return -EINVAL; 155 156 return sprintf(buf, "port_%s\n", porttypes[port->porttype]); 157 } 158 159 struct portio_sysfs_entry { 160 struct attribute attr; 161 ssize_t (*show)(struct uio_port *, char *); 162 ssize_t (*store)(struct uio_port *, const char *, size_t); 163 }; 164 165 static struct portio_sysfs_entry portio_name_attribute = 166 __ATTR(name, S_IRUGO, portio_name_show, NULL); 167 static struct portio_sysfs_entry portio_start_attribute = 168 __ATTR(start, S_IRUGO, portio_start_show, NULL); 169 static struct portio_sysfs_entry portio_size_attribute = 170 __ATTR(size, S_IRUGO, portio_size_show, NULL); 171 static struct portio_sysfs_entry portio_porttype_attribute = 172 __ATTR(porttype, S_IRUGO, portio_porttype_show, NULL); 173 174 static struct attribute *portio_attrs[] = { 175 &portio_name_attribute.attr, 176 &portio_start_attribute.attr, 177 &portio_size_attribute.attr, 178 &portio_porttype_attribute.attr, 179 NULL, 180 }; 181 182 static void portio_release(struct kobject *kobj) 183 { 184 struct uio_portio *portio = to_portio(kobj); 185 kfree(portio); 186 } 187 188 static ssize_t portio_type_show(struct kobject *kobj, struct attribute *attr, 189 char *buf) 190 { 191 struct uio_portio *portio = to_portio(kobj); 192 struct uio_port *port = portio->port; 193 struct portio_sysfs_entry *entry; 194 195 entry = container_of(attr, struct portio_sysfs_entry, attr); 196 197 if (!entry->show) 198 return -EIO; 199 200 return entry->show(port, buf); 201 } 202 203 static const struct sysfs_ops portio_sysfs_ops = { 204 .show = portio_type_show, 205 }; 206 207 static struct kobj_type portio_attr_type = { 208 .release = portio_release, 209 .sysfs_ops = &portio_sysfs_ops, 210 .default_attrs = portio_attrs, 211 }; 212 213 static ssize_t name_show(struct device *dev, 214 struct device_attribute *attr, char *buf) 215 { 216 struct uio_device *idev = dev_get_drvdata(dev); 217 int ret; 218 219 mutex_lock(&idev->info_lock); 220 if (!idev->info) { 221 ret = -EINVAL; 222 dev_err(dev, "the device has been unregistered\n"); 223 goto out; 224 } 225 226 ret = sprintf(buf, "%s\n", idev->info->name); 227 228 out: 229 mutex_unlock(&idev->info_lock); 230 return ret; 231 } 232 static DEVICE_ATTR_RO(name); 233 234 static ssize_t version_show(struct device *dev, 235 struct device_attribute *attr, char *buf) 236 { 237 struct uio_device *idev = dev_get_drvdata(dev); 238 int ret; 239 240 mutex_lock(&idev->info_lock); 241 if (!idev->info) { 242 ret = -EINVAL; 243 dev_err(dev, "the device has been unregistered\n"); 244 goto out; 245 } 246 247 ret = sprintf(buf, "%s\n", idev->info->version); 248 249 out: 250 mutex_unlock(&idev->info_lock); 251 return ret; 252 } 253 static DEVICE_ATTR_RO(version); 254 255 static ssize_t event_show(struct device *dev, 256 struct device_attribute *attr, char *buf) 257 { 258 struct uio_device *idev = dev_get_drvdata(dev); 259 return sprintf(buf, "%u\n", (unsigned int)atomic_read(&idev->event)); 260 } 261 static DEVICE_ATTR_RO(event); 262 263 static struct attribute *uio_attrs[] = { 264 &dev_attr_name.attr, 265 &dev_attr_version.attr, 266 &dev_attr_event.attr, 267 NULL, 268 }; 269 ATTRIBUTE_GROUPS(uio); 270 271 /* UIO class infrastructure */ 272 static struct class uio_class = { 273 .name = "uio", 274 .dev_groups = uio_groups, 275 }; 276 277 /* 278 * device functions 279 */ 280 static int uio_dev_add_attributes(struct uio_device *idev) 281 { 282 int ret; 283 int mi, pi; 284 int map_found = 0; 285 int portio_found = 0; 286 struct uio_mem *mem; 287 struct uio_map *map; 288 struct uio_port *port; 289 struct uio_portio *portio; 290 291 for (mi = 0; mi < MAX_UIO_MAPS; mi++) { 292 mem = &idev->info->mem[mi]; 293 if (mem->size == 0) 294 break; 295 if (!map_found) { 296 map_found = 1; 297 idev->map_dir = kobject_create_and_add("maps", 298 &idev->dev.kobj); 299 if (!idev->map_dir) { 300 ret = -ENOMEM; 301 goto err_map; 302 } 303 } 304 map = kzalloc(sizeof(*map), GFP_KERNEL); 305 if (!map) { 306 ret = -ENOMEM; 307 goto err_map; 308 } 309 kobject_init(&map->kobj, &map_attr_type); 310 map->mem = mem; 311 mem->map = map; 312 ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi); 313 if (ret) 314 goto err_map_kobj; 315 ret = kobject_uevent(&map->kobj, KOBJ_ADD); 316 if (ret) 317 goto err_map_kobj; 318 } 319 320 for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) { 321 port = &idev->info->port[pi]; 322 if (port->size == 0) 323 break; 324 if (!portio_found) { 325 portio_found = 1; 326 idev->portio_dir = kobject_create_and_add("portio", 327 &idev->dev.kobj); 328 if (!idev->portio_dir) { 329 ret = -ENOMEM; 330 goto err_portio; 331 } 332 } 333 portio = kzalloc(sizeof(*portio), GFP_KERNEL); 334 if (!portio) { 335 ret = -ENOMEM; 336 goto err_portio; 337 } 338 kobject_init(&portio->kobj, &portio_attr_type); 339 portio->port = port; 340 port->portio = portio; 341 ret = kobject_add(&portio->kobj, idev->portio_dir, 342 "port%d", pi); 343 if (ret) 344 goto err_portio_kobj; 345 ret = kobject_uevent(&portio->kobj, KOBJ_ADD); 346 if (ret) 347 goto err_portio_kobj; 348 } 349 350 return 0; 351 352 err_portio: 353 pi--; 354 err_portio_kobj: 355 for (; pi >= 0; pi--) { 356 port = &idev->info->port[pi]; 357 portio = port->portio; 358 kobject_put(&portio->kobj); 359 } 360 kobject_put(idev->portio_dir); 361 err_map: 362 mi--; 363 err_map_kobj: 364 for (; mi >= 0; mi--) { 365 mem = &idev->info->mem[mi]; 366 map = mem->map; 367 kobject_put(&map->kobj); 368 } 369 kobject_put(idev->map_dir); 370 dev_err(&idev->dev, "error creating sysfs files (%d)\n", ret); 371 return ret; 372 } 373 374 static void uio_dev_del_attributes(struct uio_device *idev) 375 { 376 int i; 377 struct uio_mem *mem; 378 struct uio_port *port; 379 380 for (i = 0; i < MAX_UIO_MAPS; i++) { 381 mem = &idev->info->mem[i]; 382 if (mem->size == 0) 383 break; 384 kobject_put(&mem->map->kobj); 385 } 386 kobject_put(idev->map_dir); 387 388 for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) { 389 port = &idev->info->port[i]; 390 if (port->size == 0) 391 break; 392 kobject_put(&port->portio->kobj); 393 } 394 kobject_put(idev->portio_dir); 395 } 396 397 static int uio_get_minor(struct uio_device *idev) 398 { 399 int retval = -ENOMEM; 400 401 mutex_lock(&minor_lock); 402 retval = idr_alloc(&uio_idr, idev, 0, UIO_MAX_DEVICES, GFP_KERNEL); 403 if (retval >= 0) { 404 idev->minor = retval; 405 retval = 0; 406 } else if (retval == -ENOSPC) { 407 dev_err(&idev->dev, "too many uio devices\n"); 408 retval = -EINVAL; 409 } 410 mutex_unlock(&minor_lock); 411 return retval; 412 } 413 414 static void uio_free_minor(struct uio_device *idev) 415 { 416 mutex_lock(&minor_lock); 417 idr_remove(&uio_idr, idev->minor); 418 mutex_unlock(&minor_lock); 419 } 420 421 /** 422 * uio_event_notify - trigger an interrupt event 423 * @info: UIO device capabilities 424 */ 425 void uio_event_notify(struct uio_info *info) 426 { 427 struct uio_device *idev = info->uio_dev; 428 429 atomic_inc(&idev->event); 430 wake_up_interruptible(&idev->wait); 431 kill_fasync(&idev->async_queue, SIGIO, POLL_IN); 432 } 433 EXPORT_SYMBOL_GPL(uio_event_notify); 434 435 /** 436 * uio_interrupt - hardware interrupt handler 437 * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer 438 * @dev_id: Pointer to the devices uio_device structure 439 */ 440 static irqreturn_t uio_interrupt(int irq, void *dev_id) 441 { 442 struct uio_device *idev = (struct uio_device *)dev_id; 443 irqreturn_t ret; 444 445 ret = idev->info->handler(irq, idev->info); 446 if (ret == IRQ_HANDLED) 447 uio_event_notify(idev->info); 448 449 return ret; 450 } 451 452 struct uio_listener { 453 struct uio_device *dev; 454 s32 event_count; 455 }; 456 457 static int uio_open(struct inode *inode, struct file *filep) 458 { 459 struct uio_device *idev; 460 struct uio_listener *listener; 461 int ret = 0; 462 463 mutex_lock(&minor_lock); 464 idev = idr_find(&uio_idr, iminor(inode)); 465 mutex_unlock(&minor_lock); 466 if (!idev) { 467 ret = -ENODEV; 468 goto out; 469 } 470 471 get_device(&idev->dev); 472 473 if (!try_module_get(idev->owner)) { 474 ret = -ENODEV; 475 goto err_module_get; 476 } 477 478 listener = kmalloc(sizeof(*listener), GFP_KERNEL); 479 if (!listener) { 480 ret = -ENOMEM; 481 goto err_alloc_listener; 482 } 483 484 listener->dev = idev; 485 listener->event_count = atomic_read(&idev->event); 486 filep->private_data = listener; 487 488 mutex_lock(&idev->info_lock); 489 if (!idev->info) { 490 mutex_unlock(&idev->info_lock); 491 ret = -EINVAL; 492 goto err_alloc_listener; 493 } 494 495 if (idev->info && idev->info->open) 496 ret = idev->info->open(idev->info, inode); 497 mutex_unlock(&idev->info_lock); 498 if (ret) 499 goto err_infoopen; 500 501 return 0; 502 503 err_infoopen: 504 kfree(listener); 505 506 err_alloc_listener: 507 module_put(idev->owner); 508 509 err_module_get: 510 put_device(&idev->dev); 511 512 out: 513 return ret; 514 } 515 516 static int uio_fasync(int fd, struct file *filep, int on) 517 { 518 struct uio_listener *listener = filep->private_data; 519 struct uio_device *idev = listener->dev; 520 521 return fasync_helper(fd, filep, on, &idev->async_queue); 522 } 523 524 static int uio_release(struct inode *inode, struct file *filep) 525 { 526 int ret = 0; 527 struct uio_listener *listener = filep->private_data; 528 struct uio_device *idev = listener->dev; 529 530 mutex_lock(&idev->info_lock); 531 if (idev->info && idev->info->release) 532 ret = idev->info->release(idev->info, inode); 533 mutex_unlock(&idev->info_lock); 534 535 module_put(idev->owner); 536 kfree(listener); 537 put_device(&idev->dev); 538 return ret; 539 } 540 541 static __poll_t uio_poll(struct file *filep, poll_table *wait) 542 { 543 struct uio_listener *listener = filep->private_data; 544 struct uio_device *idev = listener->dev; 545 __poll_t ret = 0; 546 547 mutex_lock(&idev->info_lock); 548 if (!idev->info || !idev->info->irq) 549 ret = -EIO; 550 mutex_unlock(&idev->info_lock); 551 552 if (ret) 553 return ret; 554 555 poll_wait(filep, &idev->wait, wait); 556 if (listener->event_count != atomic_read(&idev->event)) 557 return EPOLLIN | EPOLLRDNORM; 558 return 0; 559 } 560 561 static ssize_t uio_read(struct file *filep, char __user *buf, 562 size_t count, loff_t *ppos) 563 { 564 struct uio_listener *listener = filep->private_data; 565 struct uio_device *idev = listener->dev; 566 DECLARE_WAITQUEUE(wait, current); 567 ssize_t retval = 0; 568 s32 event_count; 569 570 mutex_lock(&idev->info_lock); 571 if (!idev->info || !idev->info->irq) 572 retval = -EIO; 573 mutex_unlock(&idev->info_lock); 574 575 if (retval) 576 return retval; 577 578 if (count != sizeof(s32)) 579 return -EINVAL; 580 581 add_wait_queue(&idev->wait, &wait); 582 583 do { 584 set_current_state(TASK_INTERRUPTIBLE); 585 586 event_count = atomic_read(&idev->event); 587 if (event_count != listener->event_count) { 588 __set_current_state(TASK_RUNNING); 589 if (copy_to_user(buf, &event_count, count)) 590 retval = -EFAULT; 591 else { 592 listener->event_count = event_count; 593 retval = count; 594 } 595 break; 596 } 597 598 if (filep->f_flags & O_NONBLOCK) { 599 retval = -EAGAIN; 600 break; 601 } 602 603 if (signal_pending(current)) { 604 retval = -ERESTARTSYS; 605 break; 606 } 607 schedule(); 608 } while (1); 609 610 __set_current_state(TASK_RUNNING); 611 remove_wait_queue(&idev->wait, &wait); 612 613 return retval; 614 } 615 616 static ssize_t uio_write(struct file *filep, const char __user *buf, 617 size_t count, loff_t *ppos) 618 { 619 struct uio_listener *listener = filep->private_data; 620 struct uio_device *idev = listener->dev; 621 ssize_t retval; 622 s32 irq_on; 623 624 if (count != sizeof(s32)) 625 return -EINVAL; 626 627 if (copy_from_user(&irq_on, buf, count)) 628 return -EFAULT; 629 630 mutex_lock(&idev->info_lock); 631 if (!idev->info) { 632 retval = -EINVAL; 633 goto out; 634 } 635 636 if (!idev->info || !idev->info->irq) { 637 retval = -EIO; 638 goto out; 639 } 640 641 if (!idev->info->irqcontrol) { 642 retval = -ENOSYS; 643 goto out; 644 } 645 646 retval = idev->info->irqcontrol(idev->info, irq_on); 647 648 out: 649 mutex_unlock(&idev->info_lock); 650 return retval ? retval : sizeof(s32); 651 } 652 653 static int uio_find_mem_index(struct vm_area_struct *vma) 654 { 655 struct uio_device *idev = vma->vm_private_data; 656 657 if (vma->vm_pgoff < MAX_UIO_MAPS) { 658 if (idev->info->mem[vma->vm_pgoff].size == 0) 659 return -1; 660 return (int)vma->vm_pgoff; 661 } 662 return -1; 663 } 664 665 static vm_fault_t uio_vma_fault(struct vm_fault *vmf) 666 { 667 struct uio_device *idev = vmf->vma->vm_private_data; 668 struct page *page; 669 unsigned long offset; 670 void *addr; 671 int ret = 0; 672 int mi; 673 674 mutex_lock(&idev->info_lock); 675 if (!idev->info) { 676 ret = VM_FAULT_SIGBUS; 677 goto out; 678 } 679 680 mi = uio_find_mem_index(vmf->vma); 681 if (mi < 0) { 682 ret = VM_FAULT_SIGBUS; 683 goto out; 684 } 685 686 /* 687 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE 688 * to use mem[N]. 689 */ 690 offset = (vmf->pgoff - mi) << PAGE_SHIFT; 691 692 addr = (void *)(unsigned long)idev->info->mem[mi].addr + offset; 693 if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL) 694 page = virt_to_page(addr); 695 else 696 page = vmalloc_to_page(addr); 697 get_page(page); 698 vmf->page = page; 699 700 out: 701 mutex_unlock(&idev->info_lock); 702 703 return ret; 704 } 705 706 static const struct vm_operations_struct uio_logical_vm_ops = { 707 .fault = uio_vma_fault, 708 }; 709 710 static int uio_mmap_logical(struct vm_area_struct *vma) 711 { 712 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 713 vma->vm_ops = &uio_logical_vm_ops; 714 return 0; 715 } 716 717 static const struct vm_operations_struct uio_physical_vm_ops = { 718 #ifdef CONFIG_HAVE_IOREMAP_PROT 719 .access = generic_access_phys, 720 #endif 721 }; 722 723 static int uio_mmap_physical(struct vm_area_struct *vma) 724 { 725 struct uio_device *idev = vma->vm_private_data; 726 int mi = uio_find_mem_index(vma); 727 struct uio_mem *mem; 728 729 if (mi < 0) 730 return -EINVAL; 731 mem = idev->info->mem + mi; 732 733 if (mem->addr & ~PAGE_MASK) 734 return -ENODEV; 735 if (vma->vm_end - vma->vm_start > mem->size) 736 return -EINVAL; 737 738 vma->vm_ops = &uio_physical_vm_ops; 739 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 740 741 /* 742 * We cannot use the vm_iomap_memory() helper here, 743 * because vma->vm_pgoff is the map index we looked 744 * up above in uio_find_mem_index(), rather than an 745 * actual page offset into the mmap. 746 * 747 * So we just do the physical mmap without a page 748 * offset. 749 */ 750 return remap_pfn_range(vma, 751 vma->vm_start, 752 mem->addr >> PAGE_SHIFT, 753 vma->vm_end - vma->vm_start, 754 vma->vm_page_prot); 755 } 756 757 static int uio_mmap(struct file *filep, struct vm_area_struct *vma) 758 { 759 struct uio_listener *listener = filep->private_data; 760 struct uio_device *idev = listener->dev; 761 int mi; 762 unsigned long requested_pages, actual_pages; 763 int ret = 0; 764 765 if (vma->vm_end < vma->vm_start) 766 return -EINVAL; 767 768 vma->vm_private_data = idev; 769 770 mutex_lock(&idev->info_lock); 771 if (!idev->info) { 772 ret = -EINVAL; 773 goto out; 774 } 775 776 mi = uio_find_mem_index(vma); 777 if (mi < 0) { 778 ret = -EINVAL; 779 goto out; 780 } 781 782 requested_pages = vma_pages(vma); 783 actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK) 784 + idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT; 785 if (requested_pages > actual_pages) { 786 ret = -EINVAL; 787 goto out; 788 } 789 790 if (idev->info->mmap) { 791 ret = idev->info->mmap(idev->info, vma); 792 goto out; 793 } 794 795 switch (idev->info->mem[mi].memtype) { 796 case UIO_MEM_PHYS: 797 ret = uio_mmap_physical(vma); 798 break; 799 case UIO_MEM_LOGICAL: 800 case UIO_MEM_VIRTUAL: 801 ret = uio_mmap_logical(vma); 802 break; 803 default: 804 ret = -EINVAL; 805 } 806 807 out: 808 mutex_unlock(&idev->info_lock); 809 return ret; 810 } 811 812 static const struct file_operations uio_fops = { 813 .owner = THIS_MODULE, 814 .open = uio_open, 815 .release = uio_release, 816 .read = uio_read, 817 .write = uio_write, 818 .mmap = uio_mmap, 819 .poll = uio_poll, 820 .fasync = uio_fasync, 821 .llseek = noop_llseek, 822 }; 823 824 static int uio_major_init(void) 825 { 826 static const char name[] = "uio"; 827 struct cdev *cdev = NULL; 828 dev_t uio_dev = 0; 829 int result; 830 831 result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name); 832 if (result) 833 goto out; 834 835 result = -ENOMEM; 836 cdev = cdev_alloc(); 837 if (!cdev) 838 goto out_unregister; 839 840 cdev->owner = THIS_MODULE; 841 cdev->ops = &uio_fops; 842 kobject_set_name(&cdev->kobj, "%s", name); 843 844 result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES); 845 if (result) 846 goto out_put; 847 848 uio_major = MAJOR(uio_dev); 849 uio_cdev = cdev; 850 return 0; 851 out_put: 852 kobject_put(&cdev->kobj); 853 out_unregister: 854 unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES); 855 out: 856 return result; 857 } 858 859 static void uio_major_cleanup(void) 860 { 861 unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES); 862 cdev_del(uio_cdev); 863 } 864 865 static int init_uio_class(void) 866 { 867 int ret; 868 869 /* This is the first time in here, set everything up properly */ 870 ret = uio_major_init(); 871 if (ret) 872 goto exit; 873 874 ret = class_register(&uio_class); 875 if (ret) { 876 printk(KERN_ERR "class_register failed for uio\n"); 877 goto err_class_register; 878 } 879 return 0; 880 881 err_class_register: 882 uio_major_cleanup(); 883 exit: 884 return ret; 885 } 886 887 static void release_uio_class(void) 888 { 889 class_unregister(&uio_class); 890 uio_major_cleanup(); 891 } 892 893 static void uio_device_release(struct device *dev) 894 { 895 struct uio_device *idev = dev_get_drvdata(dev); 896 897 kfree(idev); 898 } 899 900 /** 901 * uio_register_device - register a new userspace IO device 902 * @owner: module that creates the new device 903 * @parent: parent device 904 * @info: UIO device capabilities 905 * 906 * returns zero on success or a negative error code. 907 */ 908 int __uio_register_device(struct module *owner, 909 struct device *parent, 910 struct uio_info *info) 911 { 912 struct uio_device *idev; 913 int ret = 0; 914 915 if (!parent || !info || !info->name || !info->version) 916 return -EINVAL; 917 918 info->uio_dev = NULL; 919 920 idev = kzalloc(sizeof(*idev), GFP_KERNEL); 921 if (!idev) { 922 return -ENOMEM; 923 } 924 925 idev->owner = owner; 926 idev->info = info; 927 mutex_init(&idev->info_lock); 928 init_waitqueue_head(&idev->wait); 929 atomic_set(&idev->event, 0); 930 931 ret = uio_get_minor(idev); 932 if (ret) 933 return ret; 934 935 idev->dev.devt = MKDEV(uio_major, idev->minor); 936 idev->dev.class = &uio_class; 937 idev->dev.parent = parent; 938 idev->dev.release = uio_device_release; 939 dev_set_drvdata(&idev->dev, idev); 940 941 ret = dev_set_name(&idev->dev, "uio%d", idev->minor); 942 if (ret) 943 goto err_device_create; 944 945 ret = device_register(&idev->dev); 946 if (ret) 947 goto err_device_create; 948 949 ret = uio_dev_add_attributes(idev); 950 if (ret) 951 goto err_uio_dev_add_attributes; 952 953 if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) { 954 /* 955 * Note that we deliberately don't use devm_request_irq 956 * here. The parent module can unregister the UIO device 957 * and call pci_disable_msi, which requires that this 958 * irq has been freed. However, the device may have open 959 * FDs at the time of unregister and therefore may not be 960 * freed until they are released. 961 */ 962 ret = request_irq(info->irq, uio_interrupt, 963 info->irq_flags, info->name, idev); 964 if (ret) 965 goto err_request_irq; 966 } 967 968 info->uio_dev = idev; 969 return 0; 970 971 err_request_irq: 972 uio_dev_del_attributes(idev); 973 err_uio_dev_add_attributes: 974 device_unregister(&idev->dev); 975 err_device_create: 976 uio_free_minor(idev); 977 return ret; 978 } 979 EXPORT_SYMBOL_GPL(__uio_register_device); 980 981 /** 982 * uio_unregister_device - unregister a industrial IO device 983 * @info: UIO device capabilities 984 * 985 */ 986 void uio_unregister_device(struct uio_info *info) 987 { 988 struct uio_device *idev; 989 990 if (!info || !info->uio_dev) 991 return; 992 993 idev = info->uio_dev; 994 995 uio_free_minor(idev); 996 997 mutex_lock(&idev->info_lock); 998 uio_dev_del_attributes(idev); 999 1000 if (info->irq && info->irq != UIO_IRQ_CUSTOM) 1001 free_irq(info->irq, idev); 1002 1003 idev->info = NULL; 1004 mutex_unlock(&idev->info_lock); 1005 1006 device_unregister(&idev->dev); 1007 1008 return; 1009 } 1010 EXPORT_SYMBOL_GPL(uio_unregister_device); 1011 1012 static int __init uio_init(void) 1013 { 1014 return init_uio_class(); 1015 } 1016 1017 static void __exit uio_exit(void) 1018 { 1019 release_uio_class(); 1020 idr_destroy(&uio_idr); 1021 } 1022 1023 module_init(uio_init) 1024 module_exit(uio_exit) 1025 MODULE_LICENSE("GPL v2"); 1026