uio.c revision a18b630d1becdf1a087de644fea080c1977bcf10
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 28struct 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 40static int uio_major; 41static DEFINE_IDR(uio_idr); 42static const struct file_operations uio_fops; 43 44/* UIO class infrastructure */ 45static struct uio_class { 46 struct kref kref; 47 struct class *class; 48} *uio_class; 49 50/* 51 * attributes 52 */ 53 54struct 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 61static 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 76static struct kobj_attribute attr_attribute = 77 __ATTR(addr, S_IRUGO, map_attr_show, NULL); 78static struct kobj_attribute size_attribute = 79 __ATTR(size, S_IRUGO, map_attr_show, NULL); 80 81static struct attribute *attrs[] = { 82 &attr_attribute.attr, 83 &size_attribute.attr, 84 NULL, /* need to NULL terminate the list of attributes */ 85}; 86 87static void map_release(struct kobject *kobj) 88{ 89 struct uio_map *map = to_map(kobj); 90 kfree(map); 91} 92 93static struct kobj_type map_attr_type = { 94 .release = map_release, 95 .default_attrs = attrs, 96}; 97 98static 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} 107static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); 108 109static 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} 118static DEVICE_ATTR(version, S_IRUGO, show_version, NULL); 119 120static 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} 130static DEVICE_ATTR(event, S_IRUGO, show_event, NULL); 131 132static struct attribute *uio_attrs[] = { 133 &dev_attr_name.attr, 134 &dev_attr_version.attr, 135 &dev_attr_event.attr, 136 NULL, 137}; 138 139static struct attribute_group uio_attr_grp = { 140 .attrs = uio_attrs, 141}; 142 143/* 144 * device functions 145 */ 146static 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 185err: 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); 193err_group: 194 dev_err(idev->dev, "error creating sysfs files (%d)\n", ret); 195 return ret; 196} 197 198static 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 212static 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; 229exit: 230 mutex_unlock(&minor_lock); 231 return retval; 232} 233 234static 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 */ 243void 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} 251EXPORT_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 */ 258static 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 269struct uio_listener { 270 struct uio_device *dev; 271 s32 event_count; 272}; 273 274static 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 305static 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 313static 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 331static 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 345static 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 394static 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 408static 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 414static 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 420static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 421{ 422 struct uio_device *idev = vma->vm_private_data; 423 struct page *page; 424 425 int mi = uio_find_mem_index(vma); 426 if (mi < 0) 427 return VM_FAULT_SIGBUS; 428 429 if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL) 430 page = virt_to_page(idev->info->mem[mi].addr); 431 else 432 page = vmalloc_to_page((void*)idev->info->mem[mi].addr); 433 get_page(page); 434 vmf->page = page; 435 return 0; 436} 437 438static struct vm_operations_struct uio_vm_ops = { 439 .open = uio_vma_open, 440 .close = uio_vma_close, 441 .fault = uio_vma_fault, 442}; 443 444static int uio_mmap_physical(struct vm_area_struct *vma) 445{ 446 struct uio_device *idev = vma->vm_private_data; 447 int mi = uio_find_mem_index(vma); 448 if (mi < 0) 449 return -EINVAL; 450 451 vma->vm_flags |= VM_IO | VM_RESERVED; 452 453 return remap_pfn_range(vma, 454 vma->vm_start, 455 idev->info->mem[mi].addr >> PAGE_SHIFT, 456 vma->vm_end - vma->vm_start, 457 vma->vm_page_prot); 458} 459 460static int uio_mmap_logical(struct vm_area_struct *vma) 461{ 462 vma->vm_flags |= VM_RESERVED; 463 vma->vm_ops = &uio_vm_ops; 464 uio_vma_open(vma); 465 return 0; 466} 467 468static int uio_mmap(struct file *filep, struct vm_area_struct *vma) 469{ 470 struct uio_listener *listener = filep->private_data; 471 struct uio_device *idev = listener->dev; 472 int mi; 473 unsigned long requested_pages, actual_pages; 474 int ret = 0; 475 476 if (vma->vm_end < vma->vm_start) 477 return -EINVAL; 478 479 vma->vm_private_data = idev; 480 481 mi = uio_find_mem_index(vma); 482 if (mi < 0) 483 return -EINVAL; 484 485 requested_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; 486 actual_pages = (idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT; 487 if (requested_pages > actual_pages) 488 return -EINVAL; 489 490 if (idev->info->mmap) { 491 if (!try_module_get(idev->owner)) 492 return -ENODEV; 493 ret = idev->info->mmap(idev->info, vma); 494 module_put(idev->owner); 495 return ret; 496 } 497 498 switch (idev->info->mem[mi].memtype) { 499 case UIO_MEM_PHYS: 500 return uio_mmap_physical(vma); 501 case UIO_MEM_LOGICAL: 502 case UIO_MEM_VIRTUAL: 503 return uio_mmap_logical(vma); 504 default: 505 return -EINVAL; 506 } 507} 508 509static const struct file_operations uio_fops = { 510 .owner = THIS_MODULE, 511 .open = uio_open, 512 .release = uio_release, 513 .read = uio_read, 514 .mmap = uio_mmap, 515 .poll = uio_poll, 516 .fasync = uio_fasync, 517}; 518 519static int uio_major_init(void) 520{ 521 uio_major = register_chrdev(0, "uio", &uio_fops); 522 if (uio_major < 0) 523 return uio_major; 524 return 0; 525} 526 527static void uio_major_cleanup(void) 528{ 529 unregister_chrdev(uio_major, "uio"); 530} 531 532static int init_uio_class(void) 533{ 534 int ret = 0; 535 536 if (uio_class != NULL) { 537 kref_get(&uio_class->kref); 538 goto exit; 539 } 540 541 /* This is the first time in here, set everything up properly */ 542 ret = uio_major_init(); 543 if (ret) 544 goto exit; 545 546 uio_class = kzalloc(sizeof(*uio_class), GFP_KERNEL); 547 if (!uio_class) { 548 ret = -ENOMEM; 549 goto err_kzalloc; 550 } 551 552 kref_init(&uio_class->kref); 553 uio_class->class = class_create(THIS_MODULE, "uio"); 554 if (IS_ERR(uio_class->class)) { 555 ret = IS_ERR(uio_class->class); 556 printk(KERN_ERR "class_create failed for uio\n"); 557 goto err_class_create; 558 } 559 return 0; 560 561err_class_create: 562 kfree(uio_class); 563 uio_class = NULL; 564err_kzalloc: 565 uio_major_cleanup(); 566exit: 567 return ret; 568} 569 570static void release_uio_class(struct kref *kref) 571{ 572 /* Ok, we cheat as we know we only have one uio_class */ 573 class_destroy(uio_class->class); 574 kfree(uio_class); 575 uio_major_cleanup(); 576 uio_class = NULL; 577} 578 579static void uio_class_destroy(void) 580{ 581 if (uio_class) 582 kref_put(&uio_class->kref, release_uio_class); 583} 584 585/** 586 * uio_register_device - register a new userspace IO device 587 * @owner: module that creates the new device 588 * @parent: parent device 589 * @info: UIO device capabilities 590 * 591 * returns zero on success or a negative error code. 592 */ 593int __uio_register_device(struct module *owner, 594 struct device *parent, 595 struct uio_info *info) 596{ 597 struct uio_device *idev; 598 int ret = 0; 599 600 if (!parent || !info || !info->name || !info->version) 601 return -EINVAL; 602 603 info->uio_dev = NULL; 604 605 ret = init_uio_class(); 606 if (ret) 607 return ret; 608 609 idev = kzalloc(sizeof(*idev), GFP_KERNEL); 610 if (!idev) { 611 ret = -ENOMEM; 612 goto err_kzalloc; 613 } 614 615 idev->owner = owner; 616 idev->info = info; 617 init_waitqueue_head(&idev->wait); 618 atomic_set(&idev->event, 0); 619 620 ret = uio_get_minor(idev); 621 if (ret) 622 goto err_get_minor; 623 624 idev->dev = device_create(uio_class->class, parent, 625 MKDEV(uio_major, idev->minor), 626 "uio%d", idev->minor); 627 if (IS_ERR(idev->dev)) { 628 printk(KERN_ERR "UIO: device register failed\n"); 629 ret = PTR_ERR(idev->dev); 630 goto err_device_create; 631 } 632 dev_set_drvdata(idev->dev, idev); 633 634 ret = uio_dev_add_attributes(idev); 635 if (ret) 636 goto err_uio_dev_add_attributes; 637 638 info->uio_dev = idev; 639 640 if (idev->info->irq >= 0) { 641 ret = request_irq(idev->info->irq, uio_interrupt, 642 idev->info->irq_flags, idev->info->name, idev); 643 if (ret) 644 goto err_request_irq; 645 } 646 647 return 0; 648 649err_request_irq: 650 uio_dev_del_attributes(idev); 651err_uio_dev_add_attributes: 652 device_destroy(uio_class->class, MKDEV(uio_major, idev->minor)); 653err_device_create: 654 uio_free_minor(idev); 655err_get_minor: 656 kfree(idev); 657err_kzalloc: 658 uio_class_destroy(); 659 return ret; 660} 661EXPORT_SYMBOL_GPL(__uio_register_device); 662 663/** 664 * uio_unregister_device - unregister a industrial IO device 665 * @info: UIO device capabilities 666 * 667 */ 668void uio_unregister_device(struct uio_info *info) 669{ 670 struct uio_device *idev; 671 672 if (!info || !info->uio_dev) 673 return; 674 675 idev = info->uio_dev; 676 677 uio_free_minor(idev); 678 679 if (info->irq >= 0) 680 free_irq(info->irq, idev); 681 682 uio_dev_del_attributes(idev); 683 684 dev_set_drvdata(idev->dev, NULL); 685 device_destroy(uio_class->class, MKDEV(uio_major, idev->minor)); 686 kfree(idev); 687 uio_class_destroy(); 688 689 return; 690} 691EXPORT_SYMBOL_GPL(uio_unregister_device); 692 693static int __init uio_init(void) 694{ 695 return 0; 696} 697 698static void __exit uio_exit(void) 699{ 700} 701 702module_init(uio_init) 703module_exit(uio_exit) 704MODULE_LICENSE("GPL v2"); 705