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