1 /* 2 * drivers/uio/uio.c 3 * 4 * Copyright(C) 2005, Benedikt Spranger <b.spranger@linutronix.de> 5 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de> 6 * Copyright(C) 2006, Hans J. Koch <hjk@linutronix.de> 7 * Copyright(C) 2006, Greg Kroah-Hartman <greg@kroah.com> 8 * 9 * Userspace IO 10 * 11 * Base Functions 12 * 13 * Licensed under the GPLv2 only. 14 */ 15 16 #include <linux/module.h> 17 #include <linux/init.h> 18 #include <linux/poll.h> 19 #include <linux/device.h> 20 #include <linux/mm.h> 21 #include <linux/idr.h> 22 #include <linux/string.h> 23 #include <linux/kobject.h> 24 #include <linux/uio_driver.h> 25 26 #define UIO_MAX_DEVICES 255 27 28 struct uio_device { 29 struct module *owner; 30 struct device *dev; 31 int minor; 32 atomic_t event; 33 struct fasync_struct *async_queue; 34 wait_queue_head_t wait; 35 int vma_count; 36 struct uio_info *info; 37 struct kobject *map_dir; 38 }; 39 40 static int uio_major; 41 static DEFINE_IDR(uio_idr); 42 static const struct file_operations uio_fops; 43 44 /* UIO class infrastructure */ 45 static struct uio_class { 46 struct kref kref; 47 struct class *class; 48 } *uio_class; 49 50 /* 51 * attributes 52 */ 53 54 struct uio_map { 55 struct kobject kobj; 56 struct uio_mem *mem; 57 }; 58 #define to_map(map) container_of(map, struct uio_map, kobj) 59 60 static ssize_t map_addr_show(struct uio_mem *mem, char *buf) 61 { 62 return sprintf(buf, "0x%lx\n", mem->addr); 63 } 64 65 static ssize_t map_size_show(struct uio_mem *mem, char *buf) 66 { 67 return sprintf(buf, "0x%lx\n", mem->size); 68 } 69 70 struct uio_sysfs_entry { 71 struct attribute attr; 72 ssize_t (*show)(struct uio_mem *, char *); 73 ssize_t (*store)(struct uio_mem *, const char *, size_t); 74 }; 75 76 static struct uio_sysfs_entry addr_attribute = 77 __ATTR(addr, S_IRUGO, map_addr_show, NULL); 78 static struct uio_sysfs_entry size_attribute = 79 __ATTR(size, S_IRUGO, map_size_show, NULL); 80 81 static struct attribute *attrs[] = { 82 &addr_attribute.attr, 83 &size_attribute.attr, 84 NULL, /* need to NULL terminate the list of attributes */ 85 }; 86 87 static void map_release(struct kobject *kobj) 88 { 89 struct uio_map *map = to_map(kobj); 90 kfree(map); 91 } 92 93 static ssize_t map_type_show(struct kobject *kobj, struct attribute *attr, 94 char *buf) 95 { 96 struct uio_map *map = to_map(kobj); 97 struct uio_mem *mem = map->mem; 98 struct uio_sysfs_entry *entry; 99 100 entry = container_of(attr, struct uio_sysfs_entry, attr); 101 102 if (!entry->show) 103 return -EIO; 104 105 return entry->show(mem, buf); 106 } 107 108 static struct sysfs_ops uio_sysfs_ops = { 109 .show = map_type_show, 110 }; 111 112 static struct kobj_type map_attr_type = { 113 .release = map_release, 114 .sysfs_ops = &uio_sysfs_ops, 115 .default_attrs = attrs, 116 }; 117 118 static ssize_t show_name(struct device *dev, 119 struct device_attribute *attr, char *buf) 120 { 121 struct uio_device *idev = dev_get_drvdata(dev); 122 if (idev) 123 return sprintf(buf, "%s\n", idev->info->name); 124 else 125 return -ENODEV; 126 } 127 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); 128 129 static ssize_t show_version(struct device *dev, 130 struct device_attribute *attr, char *buf) 131 { 132 struct uio_device *idev = dev_get_drvdata(dev); 133 if (idev) 134 return sprintf(buf, "%s\n", idev->info->version); 135 else 136 return -ENODEV; 137 } 138 static DEVICE_ATTR(version, S_IRUGO, show_version, NULL); 139 140 static ssize_t show_event(struct device *dev, 141 struct device_attribute *attr, char *buf) 142 { 143 struct uio_device *idev = dev_get_drvdata(dev); 144 if (idev) 145 return sprintf(buf, "%u\n", 146 (unsigned int)atomic_read(&idev->event)); 147 else 148 return -ENODEV; 149 } 150 static DEVICE_ATTR(event, S_IRUGO, show_event, NULL); 151 152 static struct attribute *uio_attrs[] = { 153 &dev_attr_name.attr, 154 &dev_attr_version.attr, 155 &dev_attr_event.attr, 156 NULL, 157 }; 158 159 static struct attribute_group uio_attr_grp = { 160 .attrs = uio_attrs, 161 }; 162 163 /* 164 * device functions 165 */ 166 static int uio_dev_add_attributes(struct uio_device *idev) 167 { 168 int ret; 169 int mi; 170 int map_found = 0; 171 struct uio_mem *mem; 172 struct uio_map *map; 173 174 ret = sysfs_create_group(&idev->dev->kobj, &uio_attr_grp); 175 if (ret) 176 goto err_group; 177 178 for (mi = 0; mi < MAX_UIO_MAPS; mi++) { 179 mem = &idev->info->mem[mi]; 180 if (mem->size == 0) 181 break; 182 if (!map_found) { 183 map_found = 1; 184 idev->map_dir = kobject_create_and_add("maps", 185 &idev->dev->kobj); 186 if (!idev->map_dir) 187 goto err; 188 } 189 map = kzalloc(sizeof(*map), GFP_KERNEL); 190 if (!map) 191 goto err; 192 kobject_init(&map->kobj, &map_attr_type); 193 map->mem = mem; 194 mem->map = map; 195 ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi); 196 if (ret) 197 goto err; 198 ret = kobject_uevent(&map->kobj, KOBJ_ADD); 199 if (ret) 200 goto err; 201 } 202 203 return 0; 204 205 err: 206 for (mi--; mi>=0; mi--) { 207 mem = &idev->info->mem[mi]; 208 map = mem->map; 209 kobject_put(&map->kobj); 210 } 211 kobject_put(idev->map_dir); 212 sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp); 213 err_group: 214 dev_err(idev->dev, "error creating sysfs files (%d)\n", ret); 215 return ret; 216 } 217 218 static void uio_dev_del_attributes(struct uio_device *idev) 219 { 220 int mi; 221 struct uio_mem *mem; 222 for (mi = 0; mi < MAX_UIO_MAPS; mi++) { 223 mem = &idev->info->mem[mi]; 224 if (mem->size == 0) 225 break; 226 kobject_put(&mem->map->kobj); 227 } 228 kobject_put(idev->map_dir); 229 sysfs_remove_group(&idev->dev->kobj, &uio_attr_grp); 230 } 231 232 static int uio_get_minor(struct uio_device *idev) 233 { 234 static DEFINE_MUTEX(minor_lock); 235 int retval = -ENOMEM; 236 int id; 237 238 mutex_lock(&minor_lock); 239 if (idr_pre_get(&uio_idr, GFP_KERNEL) == 0) 240 goto exit; 241 242 retval = idr_get_new(&uio_idr, idev, &id); 243 if (retval < 0) { 244 if (retval == -EAGAIN) 245 retval = -ENOMEM; 246 goto exit; 247 } 248 idev->minor = id & MAX_ID_MASK; 249 exit: 250 mutex_unlock(&minor_lock); 251 return retval; 252 } 253 254 static void uio_free_minor(struct uio_device *idev) 255 { 256 idr_remove(&uio_idr, idev->minor); 257 } 258 259 /** 260 * uio_event_notify - trigger an interrupt event 261 * @info: UIO device capabilities 262 */ 263 void uio_event_notify(struct uio_info *info) 264 { 265 struct uio_device *idev = info->uio_dev; 266 267 atomic_inc(&idev->event); 268 wake_up_interruptible(&idev->wait); 269 kill_fasync(&idev->async_queue, SIGIO, POLL_IN); 270 } 271 EXPORT_SYMBOL_GPL(uio_event_notify); 272 273 /** 274 * uio_interrupt - hardware interrupt handler 275 * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer 276 * @dev_id: Pointer to the devices uio_device structure 277 */ 278 static irqreturn_t uio_interrupt(int irq, void *dev_id) 279 { 280 struct uio_device *idev = (struct uio_device *)dev_id; 281 irqreturn_t ret = idev->info->handler(irq, idev->info); 282 283 if (ret == IRQ_HANDLED) 284 uio_event_notify(idev->info); 285 286 return ret; 287 } 288 289 struct uio_listener { 290 struct uio_device *dev; 291 s32 event_count; 292 }; 293 294 static int uio_open(struct inode *inode, struct file *filep) 295 { 296 struct uio_device *idev; 297 struct uio_listener *listener; 298 int ret = 0; 299 300 lock_kernel(); 301 idev = idr_find(&uio_idr, iminor(inode)); 302 if (!idev) { 303 ret = -ENODEV; 304 goto out; 305 } 306 307 if (!try_module_get(idev->owner)) { 308 ret = -ENODEV; 309 goto out; 310 } 311 312 listener = kmalloc(sizeof(*listener), GFP_KERNEL); 313 if (!listener) { 314 ret = -ENOMEM; 315 goto err_alloc_listener; 316 } 317 318 listener->dev = idev; 319 listener->event_count = atomic_read(&idev->event); 320 filep->private_data = listener; 321 322 if (idev->info->open) { 323 ret = idev->info->open(idev->info, inode); 324 if (ret) 325 goto err_infoopen; 326 } 327 unlock_kernel(); 328 return 0; 329 330 err_infoopen: 331 332 kfree(listener); 333 err_alloc_listener: 334 335 module_put(idev->owner); 336 337 out: 338 unlock_kernel(); 339 return ret; 340 } 341 342 static int uio_fasync(int fd, struct file *filep, int on) 343 { 344 struct uio_listener *listener = filep->private_data; 345 struct uio_device *idev = listener->dev; 346 347 return fasync_helper(fd, filep, on, &idev->async_queue); 348 } 349 350 static int uio_release(struct inode *inode, struct file *filep) 351 { 352 int ret = 0; 353 struct uio_listener *listener = filep->private_data; 354 struct uio_device *idev = listener->dev; 355 356 if (idev->info->release) 357 ret = idev->info->release(idev->info, inode); 358 359 module_put(idev->owner); 360 361 if (filep->f_flags & FASYNC) 362 ret = uio_fasync(-1, filep, 0); 363 kfree(listener); 364 return ret; 365 } 366 367 static unsigned int uio_poll(struct file *filep, poll_table *wait) 368 { 369 struct uio_listener *listener = filep->private_data; 370 struct uio_device *idev = listener->dev; 371 372 if (idev->info->irq == UIO_IRQ_NONE) 373 return -EIO; 374 375 poll_wait(filep, &idev->wait, wait); 376 if (listener->event_count != atomic_read(&idev->event)) 377 return POLLIN | POLLRDNORM; 378 return 0; 379 } 380 381 static ssize_t uio_read(struct file *filep, char __user *buf, 382 size_t count, loff_t *ppos) 383 { 384 struct uio_listener *listener = filep->private_data; 385 struct uio_device *idev = listener->dev; 386 DECLARE_WAITQUEUE(wait, current); 387 ssize_t retval; 388 s32 event_count; 389 390 if (idev->info->irq == UIO_IRQ_NONE) 391 return -EIO; 392 393 if (count != sizeof(s32)) 394 return -EINVAL; 395 396 add_wait_queue(&idev->wait, &wait); 397 398 do { 399 set_current_state(TASK_INTERRUPTIBLE); 400 401 event_count = atomic_read(&idev->event); 402 if (event_count != listener->event_count) { 403 if (copy_to_user(buf, &event_count, count)) 404 retval = -EFAULT; 405 else { 406 listener->event_count = event_count; 407 retval = count; 408 } 409 break; 410 } 411 412 if (filep->f_flags & O_NONBLOCK) { 413 retval = -EAGAIN; 414 break; 415 } 416 417 if (signal_pending(current)) { 418 retval = -ERESTARTSYS; 419 break; 420 } 421 schedule(); 422 } while (1); 423 424 __set_current_state(TASK_RUNNING); 425 remove_wait_queue(&idev->wait, &wait); 426 427 return retval; 428 } 429 430 static ssize_t uio_write(struct file *filep, const char __user *buf, 431 size_t count, loff_t *ppos) 432 { 433 struct uio_listener *listener = filep->private_data; 434 struct uio_device *idev = listener->dev; 435 ssize_t retval; 436 s32 irq_on; 437 438 if (idev->info->irq == UIO_IRQ_NONE) 439 return -EIO; 440 441 if (count != sizeof(s32)) 442 return -EINVAL; 443 444 if (!idev->info->irqcontrol) 445 return -ENOSYS; 446 447 if (copy_from_user(&irq_on, buf, count)) 448 return -EFAULT; 449 450 retval = idev->info->irqcontrol(idev->info, irq_on); 451 452 return retval ? retval : sizeof(s32); 453 } 454 455 static int uio_find_mem_index(struct vm_area_struct *vma) 456 { 457 int mi; 458 struct uio_device *idev = vma->vm_private_data; 459 460 for (mi = 0; mi < MAX_UIO_MAPS; mi++) { 461 if (idev->info->mem[mi].size == 0) 462 return -1; 463 if (vma->vm_pgoff == mi) 464 return mi; 465 } 466 return -1; 467 } 468 469 static void uio_vma_open(struct vm_area_struct *vma) 470 { 471 struct uio_device *idev = vma->vm_private_data; 472 idev->vma_count++; 473 } 474 475 static void uio_vma_close(struct vm_area_struct *vma) 476 { 477 struct uio_device *idev = vma->vm_private_data; 478 idev->vma_count--; 479 } 480 481 static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 482 { 483 struct uio_device *idev = vma->vm_private_data; 484 struct page *page; 485 486 int mi = uio_find_mem_index(vma); 487 if (mi < 0) 488 return VM_FAULT_SIGBUS; 489 490 if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL) 491 page = virt_to_page(idev->info->mem[mi].addr); 492 else 493 page = vmalloc_to_page((void*)idev->info->mem[mi].addr); 494 get_page(page); 495 vmf->page = page; 496 return 0; 497 } 498 499 static struct vm_operations_struct uio_vm_ops = { 500 .open = uio_vma_open, 501 .close = uio_vma_close, 502 .fault = uio_vma_fault, 503 }; 504 505 static int uio_mmap_physical(struct vm_area_struct *vma) 506 { 507 struct uio_device *idev = vma->vm_private_data; 508 int mi = uio_find_mem_index(vma); 509 if (mi < 0) 510 return -EINVAL; 511 512 vma->vm_flags |= VM_IO | VM_RESERVED; 513 514 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 515 516 return remap_pfn_range(vma, 517 vma->vm_start, 518 idev->info->mem[mi].addr >> PAGE_SHIFT, 519 vma->vm_end - vma->vm_start, 520 vma->vm_page_prot); 521 } 522 523 static int uio_mmap_logical(struct vm_area_struct *vma) 524 { 525 vma->vm_flags |= VM_RESERVED; 526 vma->vm_ops = &uio_vm_ops; 527 uio_vma_open(vma); 528 return 0; 529 } 530 531 static int uio_mmap(struct file *filep, struct vm_area_struct *vma) 532 { 533 struct uio_listener *listener = filep->private_data; 534 struct uio_device *idev = listener->dev; 535 int mi; 536 unsigned long requested_pages, actual_pages; 537 int ret = 0; 538 539 if (vma->vm_end < vma->vm_start) 540 return -EINVAL; 541 542 vma->vm_private_data = idev; 543 544 mi = uio_find_mem_index(vma); 545 if (mi < 0) 546 return -EINVAL; 547 548 requested_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; 549 actual_pages = (idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT; 550 if (requested_pages > actual_pages) 551 return -EINVAL; 552 553 if (idev->info->mmap) { 554 ret = idev->info->mmap(idev->info, vma); 555 return ret; 556 } 557 558 switch (idev->info->mem[mi].memtype) { 559 case UIO_MEM_PHYS: 560 return uio_mmap_physical(vma); 561 case UIO_MEM_LOGICAL: 562 case UIO_MEM_VIRTUAL: 563 return uio_mmap_logical(vma); 564 default: 565 return -EINVAL; 566 } 567 } 568 569 static const struct file_operations uio_fops = { 570 .owner = THIS_MODULE, 571 .open = uio_open, 572 .release = uio_release, 573 .read = uio_read, 574 .write = uio_write, 575 .mmap = uio_mmap, 576 .poll = uio_poll, 577 .fasync = uio_fasync, 578 }; 579 580 static int uio_major_init(void) 581 { 582 uio_major = register_chrdev(0, "uio", &uio_fops); 583 if (uio_major < 0) 584 return uio_major; 585 return 0; 586 } 587 588 static void uio_major_cleanup(void) 589 { 590 unregister_chrdev(uio_major, "uio"); 591 } 592 593 static int init_uio_class(void) 594 { 595 int ret = 0; 596 597 if (uio_class != NULL) { 598 kref_get(&uio_class->kref); 599 goto exit; 600 } 601 602 /* This is the first time in here, set everything up properly */ 603 ret = uio_major_init(); 604 if (ret) 605 goto exit; 606 607 uio_class = kzalloc(sizeof(*uio_class), GFP_KERNEL); 608 if (!uio_class) { 609 ret = -ENOMEM; 610 goto err_kzalloc; 611 } 612 613 kref_init(&uio_class->kref); 614 uio_class->class = class_create(THIS_MODULE, "uio"); 615 if (IS_ERR(uio_class->class)) { 616 ret = IS_ERR(uio_class->class); 617 printk(KERN_ERR "class_create failed for uio\n"); 618 goto err_class_create; 619 } 620 return 0; 621 622 err_class_create: 623 kfree(uio_class); 624 uio_class = NULL; 625 err_kzalloc: 626 uio_major_cleanup(); 627 exit: 628 return ret; 629 } 630 631 static void release_uio_class(struct kref *kref) 632 { 633 /* Ok, we cheat as we know we only have one uio_class */ 634 class_destroy(uio_class->class); 635 kfree(uio_class); 636 uio_major_cleanup(); 637 uio_class = NULL; 638 } 639 640 static void uio_class_destroy(void) 641 { 642 if (uio_class) 643 kref_put(&uio_class->kref, release_uio_class); 644 } 645 646 /** 647 * uio_register_device - register a new userspace IO device 648 * @owner: module that creates the new device 649 * @parent: parent device 650 * @info: UIO device capabilities 651 * 652 * returns zero on success or a negative error code. 653 */ 654 int __uio_register_device(struct module *owner, 655 struct device *parent, 656 struct uio_info *info) 657 { 658 struct uio_device *idev; 659 int ret = 0; 660 661 if (!parent || !info || !info->name || !info->version) 662 return -EINVAL; 663 664 info->uio_dev = NULL; 665 666 ret = init_uio_class(); 667 if (ret) 668 return ret; 669 670 idev = kzalloc(sizeof(*idev), GFP_KERNEL); 671 if (!idev) { 672 ret = -ENOMEM; 673 goto err_kzalloc; 674 } 675 676 idev->owner = owner; 677 idev->info = info; 678 init_waitqueue_head(&idev->wait); 679 atomic_set(&idev->event, 0); 680 681 ret = uio_get_minor(idev); 682 if (ret) 683 goto err_get_minor; 684 685 idev->dev = device_create_drvdata(uio_class->class, parent, 686 MKDEV(uio_major, idev->minor), idev, 687 "uio%d", idev->minor); 688 if (IS_ERR(idev->dev)) { 689 printk(KERN_ERR "UIO: device register failed\n"); 690 ret = PTR_ERR(idev->dev); 691 goto err_device_create; 692 } 693 694 ret = uio_dev_add_attributes(idev); 695 if (ret) 696 goto err_uio_dev_add_attributes; 697 698 info->uio_dev = idev; 699 700 if (idev->info->irq >= 0) { 701 ret = request_irq(idev->info->irq, uio_interrupt, 702 idev->info->irq_flags, idev->info->name, idev); 703 if (ret) 704 goto err_request_irq; 705 } 706 707 return 0; 708 709 err_request_irq: 710 uio_dev_del_attributes(idev); 711 err_uio_dev_add_attributes: 712 device_destroy(uio_class->class, MKDEV(uio_major, idev->minor)); 713 err_device_create: 714 uio_free_minor(idev); 715 err_get_minor: 716 kfree(idev); 717 err_kzalloc: 718 uio_class_destroy(); 719 return ret; 720 } 721 EXPORT_SYMBOL_GPL(__uio_register_device); 722 723 /** 724 * uio_unregister_device - unregister a industrial IO device 725 * @info: UIO device capabilities 726 * 727 */ 728 void uio_unregister_device(struct uio_info *info) 729 { 730 struct uio_device *idev; 731 732 if (!info || !info->uio_dev) 733 return; 734 735 idev = info->uio_dev; 736 737 uio_free_minor(idev); 738 739 if (info->irq >= 0) 740 free_irq(info->irq, idev); 741 742 uio_dev_del_attributes(idev); 743 744 dev_set_drvdata(idev->dev, NULL); 745 device_destroy(uio_class->class, MKDEV(uio_major, idev->minor)); 746 kfree(idev); 747 uio_class_destroy(); 748 749 return; 750 } 751 EXPORT_SYMBOL_GPL(uio_unregister_device); 752 753 static int __init uio_init(void) 754 { 755 return 0; 756 } 757 758 static void __exit uio_exit(void) 759 { 760 } 761 762 module_init(uio_init) 763 module_exit(uio_exit) 764 MODULE_LICENSE("GPL v2"); 765