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