drivers/uio/uio.c

   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/signal.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
  31 static int uio_major;
  32 static struct cdev *uio_cdev;
  33 static DEFINE_IDR(uio_idr);
  34 static const struct file_operations uio_fops;
  35
  36 /* Protect idr accesses */
  37 static DEFINE_MUTEX(minor_lock);
  38
  39 /*
  40  * attributes
  41  */
  42
  43 struct uio_map {
  44         struct kobject kobj;
  45         struct uio_mem *mem;
  46 };
  47 #define to_map(map) container_of(map, struct uio_map, kobj)
  48
  49 static ssize_t map_name_show(struct uio_mem *mem, char *buf)
  50 {
  51         if (unlikely(!mem->name))
  52                 mem->name = "";
  53
  54         return sprintf(buf, "%s\n", mem->name);
  55 }
  56
  57 static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
  58 {
  59         return sprintf(buf, "%pa\n", &mem->addr);
  60 }
  61
  62 static ssize_t map_size_show(struct uio_mem *mem, char *buf)
  63 {
  64         return sprintf(buf, "%pa\n", &mem->size);
  65 }
  66
  67 static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
  68 {
  69         return sprintf(buf, "0x%llx\n", (unsigned long long)mem->offs);
  70 }
  71
  72 struct map_sysfs_entry {
  73         struct attribute attr;
  74         ssize_t (*show)(struct uio_mem *, char *);
  75         ssize_t (*store)(struct uio_mem *, const char *, size_t);
  76 };
  77
  78 static struct map_sysfs_entry name_attribute =
  79         __ATTR(name, S_IRUGO, map_name_show, NULL);
  80 static struct map_sysfs_entry addr_attribute =
  81         __ATTR(addr, S_IRUGO, map_addr_show, NULL);
  82 static struct map_sysfs_entry size_attribute =
  83         __ATTR(size, S_IRUGO, map_size_show, NULL);
  84 static struct map_sysfs_entry offset_attribute =
  85         __ATTR(offset, S_IRUGO, map_offset_show, NULL);
  86
  87 static struct attribute *attrs[] = {
  88         &name_attribute.attr,
  89         &addr_attribute.attr,
  90         &size_attribute.attr,
  91         &offset_attribute.attr,
  92         NULL,   /* need to NULL terminate the list of attributes */
  93 };
  94
  95 static void map_release(struct kobject *kobj)
  96 {
  97         struct uio_map *map = to_map(kobj);
  98         kfree(map);
  99 }
 100
 101 static ssize_t map_type_show(struct kobject *kobj, struct attribute *attr,
 102                              char *buf)
 103 {
 104         struct uio_map *map = to_map(kobj);
 105         struct uio_mem *mem = map->mem;
 106         struct map_sysfs_entry *entry;
 107
 108         entry = container_of(attr, struct map_sysfs_entry, attr);
 109
 110         if (!entry->show)
 111                 return -EIO;
 112
 113         return entry->show(mem, buf);
 114 }
 115
 116 static const struct sysfs_ops map_sysfs_ops = {
 117         .show = map_type_show,
 118 };
 119
 120 static struct kobj_type map_attr_type = {
 121         .release        = map_release,
 122         .sysfs_ops      = &map_sysfs_ops,
 123         .default_attrs  = attrs,
 124 };
 125
 126 struct uio_portio {
 127         struct kobject kobj;
 128         struct uio_port *port;
 129 };
 130 #define to_portio(portio) container_of(portio, struct uio_portio, kobj)
 131
 132 static ssize_t portio_name_show(struct uio_port *port, char *buf)
 133 {
 134         if (unlikely(!port->name))
 135                 port->name = "";
 136
 137         return sprintf(buf, "%s\n", port->name);
 138 }
 139
 140 static ssize_t portio_start_show(struct uio_port *port, char *buf)
 141 {
 142         return sprintf(buf, "0x%lx\n", port->start);
 143 }
 144
 145 static ssize_t portio_size_show(struct uio_port *port, char *buf)
 146 {
 147         return sprintf(buf, "0x%lx\n", port->size);
 148 }
 149
 150 static ssize_t portio_porttype_show(struct uio_port *port, char *buf)
 151 {
 152         const char *porttypes[] = {"none", "x86", "gpio", "other"};
 153
 154         if ((port->porttype < 0) || (port->porttype > UIO_PORT_OTHER))
 155                 return -EINVAL;
 156
 157         return sprintf(buf, "port_%s\n", porttypes[port->porttype]);
 158 }
 159
 160 struct portio_sysfs_entry {
 161         struct attribute attr;
 162         ssize_t (*show)(struct uio_port *, char *);
 163         ssize_t (*store)(struct uio_port *, const char *, size_t);
 164 };
 165
 166 static struct portio_sysfs_entry portio_name_attribute =
 167         __ATTR(name, S_IRUGO, portio_name_show, NULL);
 168 static struct portio_sysfs_entry portio_start_attribute =
 169         __ATTR(start, S_IRUGO, portio_start_show, NULL);
 170 static struct portio_sysfs_entry portio_size_attribute =
 171         __ATTR(size, S_IRUGO, portio_size_show, NULL);
 172 static struct portio_sysfs_entry portio_porttype_attribute =
 173         __ATTR(porttype, S_IRUGO, portio_porttype_show, NULL);
 174
 175 static struct attribute *portio_attrs[] = {
 176         &portio_name_attribute.attr,
 177         &portio_start_attribute.attr,
 178         &portio_size_attribute.attr,
 179         &portio_porttype_attribute.attr,
 180         NULL,
 181 };
 182
 183 static void portio_release(struct kobject *kobj)
 184 {
 185         struct uio_portio *portio = to_portio(kobj);
 186         kfree(portio);
 187 }
 188
 189 static ssize_t portio_type_show(struct kobject *kobj, struct attribute *attr,
 190                              char *buf)
 191 {
 192         struct uio_portio *portio = to_portio(kobj);
 193         struct uio_port *port = portio->port;
 194         struct portio_sysfs_entry *entry;
 195
 196         entry = container_of(attr, struct portio_sysfs_entry, attr);
 197
 198         if (!entry->show)
 199                 return -EIO;
 200
 201         return entry->show(port, buf);
 202 }
 203
 204 static const struct sysfs_ops portio_sysfs_ops = {
 205         .show = portio_type_show,
 206 };
 207
 208 static struct kobj_type portio_attr_type = {
 209         .release        = portio_release,
 210         .sysfs_ops      = &portio_sysfs_ops,
 211         .default_attrs  = portio_attrs,
 212 };
 213
 214 static ssize_t name_show(struct device *dev,
 215                          struct device_attribute *attr, char *buf)
 216 {
 217         struct uio_device *idev = dev_get_drvdata(dev);
 218         int ret;
 219
 220         mutex_lock(&idev->info_lock);
 221         if (!idev->info) {
 222                 ret = -EINVAL;
 223                 dev_err(dev, "the device has been unregistered\n");
 224                 goto out;
 225         }
 226
 227         ret = sprintf(buf, "%s\n", idev->info->name);
 228
 229 out:
 230         mutex_unlock(&idev->info_lock);
 231         return ret;
 232 }
 233 static DEVICE_ATTR_RO(name);
 234
 235 static ssize_t version_show(struct device *dev,
 236                             struct device_attribute *attr, char *buf)
 237 {
 238         struct uio_device *idev = dev_get_drvdata(dev);
 239         int ret;
 240
 241         mutex_lock(&idev->info_lock);
 242         if (!idev->info) {
 243                 ret = -EINVAL;
 244                 dev_err(dev, "the device has been unregistered\n");
 245                 goto out;
 246         }
 247
 248         ret = sprintf(buf, "%s\n", idev->info->version);
 249
 250 out:
 251         mutex_unlock(&idev->info_lock);
 252         return ret;
 253 }
 254 static DEVICE_ATTR_RO(version);
 255
 256 static ssize_t event_show(struct device *dev,
 257                           struct device_attribute *attr, char *buf)
 258 {
 259         struct uio_device *idev = dev_get_drvdata(dev);
 260         return sprintf(buf, "%u\n", (unsigned int)atomic_read(&idev->event));
 261 }
 262 static DEVICE_ATTR_RO(event);
 263
 264 static struct attribute *uio_attrs[] = {
 265         &dev_attr_name.attr,
 266         &dev_attr_version.attr,
 267         &dev_attr_event.attr,
 268         NULL,
 269 };
 270 ATTRIBUTE_GROUPS(uio);
 271
 272 /* UIO class infrastructure */
 273 static struct class uio_class = {
 274         .name = "uio",
 275         .dev_groups = uio_groups,
 276 };
 277
 278 /*
 279  * device functions
 280  */
 281 static int uio_dev_add_attributes(struct uio_device *idev)
 282 {
 283         int ret;
 284         int mi, pi;
 285         int map_found = 0;
 286         int portio_found = 0;
 287         struct uio_mem *mem;
 288         struct uio_map *map;
 289         struct uio_port *port;
 290         struct uio_portio *portio;
 291
 292         for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
 293                 mem = &idev->info->mem[mi];
 294                 if (mem->size == 0)
 295                         break;
 296                 if (!map_found) {
 297                         map_found = 1;
 298                         idev->map_dir = kobject_create_and_add("maps",
 299                                                         &idev->dev.kobj);
 300                         if (!idev->map_dir) {
 301                                 ret = -ENOMEM;
 302                                 goto err_map;
 303                         }
 304                 }
 305                 map = kzalloc(sizeof(*map), GFP_KERNEL);
 306                 if (!map) {
 307                         ret = -ENOMEM;
 308                         goto err_map;
 309                 }
 310                 kobject_init(&map->kobj, &map_attr_type);
 311                 map->mem = mem;
 312                 mem->map = map;
 313                 ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
 314                 if (ret)
 315                         goto err_map_kobj;
 316                 ret = kobject_uevent(&map->kobj, KOBJ_ADD);
 317                 if (ret)
 318                         goto err_map_kobj;
 319         }
 320
 321         for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
 322                 port = &idev->info->port[pi];
 323                 if (port->size == 0)
 324                         break;
 325                 if (!portio_found) {
 326                         portio_found = 1;
 327                         idev->portio_dir = kobject_create_and_add("portio",
 328                                                         &idev->dev.kobj);
 329                         if (!idev->portio_dir) {
 330                                 ret = -ENOMEM;
 331                                 goto err_portio;
 332                         }
 333                 }
 334                 portio = kzalloc(sizeof(*portio), GFP_KERNEL);
 335                 if (!portio) {
 336                         ret = -ENOMEM;
 337                         goto err_portio;
 338                 }
 339                 kobject_init(&portio->kobj, &portio_attr_type);
 340                 portio->port = port;
 341                 port->portio = portio;
 342                 ret = kobject_add(&portio->kobj, idev->portio_dir,
 343                                                         "port%d", pi);
 344                 if (ret)
 345                         goto err_portio_kobj;
 346                 ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
 347                 if (ret)
 348                         goto err_portio_kobj;
 349         }
 350
 351         return 0;
 352
 353 err_portio:
 354         pi--;
 355 err_portio_kobj:
 356         for (; pi >= 0; pi--) {
 357                 port = &idev->info->port[pi];
 358                 portio = port->portio;
 359                 kobject_put(&portio->kobj);
 360         }
 361         kobject_put(idev->portio_dir);
 362 err_map:
 363         mi--;
 364 err_map_kobj:
 365         for (; mi >= 0; mi--) {
 366                 mem = &idev->info->mem[mi];
 367                 map = mem->map;
 368                 kobject_put(&map->kobj);
 369         }
 370         kobject_put(idev->map_dir);
 371         dev_err(&idev->dev, "error creating sysfs files (%d)\n", ret);
 372         return ret;
 373 }
 374
 375 static void uio_dev_del_attributes(struct uio_device *idev)
 376 {
 377         int i;
 378         struct uio_mem *mem;
 379         struct uio_port *port;
 380
 381         for (i = 0; i < MAX_UIO_MAPS; i++) {
 382                 mem = &idev->info->mem[i];
 383                 if (mem->size == 0)
 384                         break;
 385                 kobject_put(&mem->map->kobj);
 386         }
 387         kobject_put(idev->map_dir);
 388
 389         for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
 390                 port = &idev->info->port[i];
 391                 if (port->size == 0)
 392                         break;
 393                 kobject_put(&port->portio->kobj);
 394         }
 395         kobject_put(idev->portio_dir);
 396 }
 397
 398 static int uio_get_minor(struct uio_device *idev)
 399 {
 400         int retval = -ENOMEM;
 401
 402         mutex_lock(&minor_lock);
 403         retval = idr_alloc(&uio_idr, idev, 0, UIO_MAX_DEVICES, GFP_KERNEL);
 404         if (retval >= 0) {
 405                 idev->minor = retval;
 406                 retval = 0;
 407         } else if (retval == -ENOSPC) {
 408                 dev_err(&idev->dev, "too many uio devices\n");
 409                 retval = -EINVAL;
 410         }
 411         mutex_unlock(&minor_lock);
 412         return retval;
 413 }
 414
 415 static void uio_free_minor(struct uio_device *idev)
 416 {
 417         mutex_lock(&minor_lock);
 418         idr_remove(&uio_idr, idev->minor);
 419         mutex_unlock(&minor_lock);
 420 }
 421
 422 /**
 423  * uio_event_notify - trigger an interrupt event
 424  * @info: UIO device capabilities
 425  */
 426 void uio_event_notify(struct uio_info *info)
 427 {
 428         struct uio_device *idev = info->uio_dev;
 429
 430         atomic_inc(&idev->event);
 431         wake_up_interruptible(&idev->wait);
 432         kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
 433 }
 434 EXPORT_SYMBOL_GPL(uio_event_notify);
 435
 436 /**
 437  * uio_interrupt - hardware interrupt handler
 438  * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
 439  * @dev_id: Pointer to the devices uio_device structure
 440  */
 441 static irqreturn_t uio_interrupt(int irq, void *dev_id)
 442 {
 443         struct uio_device *idev = (struct uio_device *)dev_id;
 444         irqreturn_t ret;
 445
 446         ret = idev->info->handler(irq, idev->info);
 447         if (ret == IRQ_HANDLED)
 448                 uio_event_notify(idev->info);
 449
 450         return ret;
 451 }
 452
 453 struct uio_listener {
 454         struct uio_device *dev;
 455         s32 event_count;
 456 };
 457
 458 static int uio_open(struct inode *inode, struct file *filep)
 459 {
 460         struct uio_device *idev;
 461         struct uio_listener *listener;
 462         int ret = 0;
 463
 464         mutex_lock(&minor_lock);
 465         idev = idr_find(&uio_idr, iminor(inode));
 466         mutex_unlock(&minor_lock);
 467         if (!idev) {
 468                 ret = -ENODEV;
 469                 goto out;
 470         }
 471
 472         get_device(&idev->dev);
 473
 474         if (!try_module_get(idev->owner)) {
 475                 ret = -ENODEV;
 476                 goto err_module_get;
 477         }
 478
 479         listener = kmalloc(sizeof(*listener), GFP_KERNEL);
 480         if (!listener) {
 481                 ret = -ENOMEM;
 482                 goto err_alloc_listener;
 483         }
 484
 485         listener->dev = idev;
 486         listener->event_count = atomic_read(&idev->event);
 487         filep->private_data = listener;
 488
 489         mutex_lock(&idev->info_lock);
 490         if (!idev->info) {
 491                 mutex_unlock(&idev->info_lock);
 492                 ret = -EINVAL;
 493                 goto err_alloc_listener;
 494         }
 495
 496         if (idev->info && idev->info->open)
 497                 ret = idev->info->open(idev->info, inode);
 498         mutex_unlock(&idev->info_lock);
 499         if (ret)
 500                 goto err_infoopen;
 501
 502         return 0;
 503
 504 err_infoopen:
 505         kfree(listener);
 506
 507 err_alloc_listener:
 508         module_put(idev->owner);
 509
 510 err_module_get:
 511         put_device(&idev->dev);
 512
 513 out:
 514         return ret;
 515 }
 516
 517 static int uio_fasync(int fd, struct file *filep, int on)
 518 {
 519         struct uio_listener *listener = filep->private_data;
 520         struct uio_device *idev = listener->dev;
 521
 522         return fasync_helper(fd, filep, on, &idev->async_queue);
 523 }
 524
 525 static int uio_release(struct inode *inode, struct file *filep)
 526 {
 527         int ret = 0;
 528         struct uio_listener *listener = filep->private_data;
 529         struct uio_device *idev = listener->dev;
 530
 531         mutex_lock(&idev->info_lock);
 532         if (idev->info && idev->info->release)
 533                 ret = idev->info->release(idev->info, inode);
 534         mutex_unlock(&idev->info_lock);
 535
 536         module_put(idev->owner);
 537         kfree(listener);
 538         put_device(&idev->dev);
 539         return ret;
 540 }
 541
 542 static __poll_t uio_poll(struct file *filep, poll_table *wait)
 543 {
 544         struct uio_listener *listener = filep->private_data;
 545         struct uio_device *idev = listener->dev;
 546         __poll_t ret = 0;
 547
 548         mutex_lock(&idev->info_lock);
 549         if (!idev->info || !idev->info->irq)
 550                 ret = -EIO;
 551         mutex_unlock(&idev->info_lock);
 552
 553         if (ret)
 554                 return ret;
 555
 556         poll_wait(filep, &idev->wait, wait);
 557         if (listener->event_count != atomic_read(&idev->event))
 558                 return EPOLLIN | EPOLLRDNORM;
 559         return 0;
 560 }
 561
 562 static ssize_t uio_read(struct file *filep, char __user *buf,
 563                         size_t count, loff_t *ppos)
 564 {
 565         struct uio_listener *listener = filep->private_data;
 566         struct uio_device *idev = listener->dev;
 567         DECLARE_WAITQUEUE(wait, current);
 568         ssize_t retval = 0;
 569         s32 event_count;
 570
 571         mutex_lock(&idev->info_lock);
 572         if (!idev->info || !idev->info->irq)
 573                 retval = -EIO;
 574         mutex_unlock(&idev->info_lock);
 575
 576         if (retval)
 577                 return retval;
 578
 579         if (count != sizeof(s32))
 580                 return -EINVAL;
 581
 582         add_wait_queue(&idev->wait, &wait);
 583
 584         do {
 585                 set_current_state(TASK_INTERRUPTIBLE);
 586
 587                 event_count = atomic_read(&idev->event);
 588                 if (event_count != listener->event_count) {
 589                         __set_current_state(TASK_RUNNING);
 590                         if (copy_to_user(buf, &event_count, count))
 591                                 retval = -EFAULT;
 592                         else {
 593                                 listener->event_count = event_count;
 594                                 retval = count;
 595                         }
 596                         break;
 597                 }
 598
 599                 if (filep->f_flags & O_NONBLOCK) {
 600                         retval = -EAGAIN;
 601                         break;
 602                 }
 603
 604                 if (signal_pending(current)) {
 605                         retval = -ERESTARTSYS;
 606                         break;
 607                 }
 608                 schedule();
 609         } while (1);
 610
 611         __set_current_state(TASK_RUNNING);
 612         remove_wait_queue(&idev->wait, &wait);
 613
 614         return retval;
 615 }
 616
 617 static ssize_t uio_write(struct file *filep, const char __user *buf,
 618                         size_t count, loff_t *ppos)
 619 {
 620         struct uio_listener *listener = filep->private_data;
 621         struct uio_device *idev = listener->dev;
 622         ssize_t retval;
 623         s32 irq_on;
 624
 625         mutex_lock(&idev->info_lock);
 626         if (!idev->info) {
 627                 retval = -EINVAL;
 628                 goto out;
 629         }
 630
 631         if (!idev->info || !idev->info->irq) {
 632                 retval = -EIO;
 633                 goto out;
 634         }
 635
 636         if (count != sizeof(s32)) {
 637                 retval = -EINVAL;
 638                 goto out;
 639         }
 640
 641         if (!idev->info->irqcontrol) {
 642                 retval = -ENOSYS;
 643                 goto out;
 644         }
 645
 646         if (copy_from_user(&irq_on, buf, count)) {
 647                 retval = -EFAULT;
 648                 goto out;
 649         }
 650
 651         retval = idev->info->irqcontrol(idev->info, irq_on);
 652
 653 out:
 654         mutex_unlock(&idev->info_lock);
 655         return retval ? retval : sizeof(s32);
 656 }
 657
 658 static int uio_find_mem_index(struct vm_area_struct *vma)
 659 {
 660         struct uio_device *idev = vma->vm_private_data;
 661
 662         if (vma->vm_pgoff < MAX_UIO_MAPS) {
 663                 if (idev->info->mem[vma->vm_pgoff].size == 0)
 664                         return -1;
 665                 return (int)vma->vm_pgoff;
 666         }
 667         return -1;
 668 }
 669
 670 static vm_fault_t uio_vma_fault(struct vm_fault *vmf)
 671 {
 672         struct uio_device *idev = vmf->vma->vm_private_data;
 673         struct page *page;
 674         unsigned long offset;
 675         void *addr;
 676         int ret = 0;
 677         int mi;
 678
 679         mutex_lock(&idev->info_lock);
 680         if (!idev->info) {
 681                 ret = VM_FAULT_SIGBUS;
 682                 goto out;
 683         }
 684
 685         mi = uio_find_mem_index(vmf->vma);
 686         if (mi < 0) {
 687                 ret = VM_FAULT_SIGBUS;
 688                 goto out;
 689         }
 690
 691         /*
 692          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
 693          * to use mem[N].
 694          */
 695         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
 696
 697         addr = (void *)(unsigned long)idev->info->mem[mi].addr + offset;
 698         if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
 699                 page = virt_to_page(addr);
 700         else
 701                 page = vmalloc_to_page(addr);
 702         get_page(page);
 703         vmf->page = page;
 704
 705 out:
 706         mutex_unlock(&idev->info_lock);
 707
 708         return ret;
 709 }
 710
 711 static const struct vm_operations_struct uio_logical_vm_ops = {
 712         .fault = uio_vma_fault,
 713 };
 714
 715 static int uio_mmap_logical(struct vm_area_struct *vma)
 716 {
 717         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
 718         vma->vm_ops = &uio_logical_vm_ops;
 719         return 0;
 720 }
 721
 722 static const struct vm_operations_struct uio_physical_vm_ops = {
 723 #ifdef CONFIG_HAVE_IOREMAP_PROT
 724         .access = generic_access_phys,
 725 #endif
 726 };
 727
 728 static int uio_mmap_physical(struct vm_area_struct *vma)
 729 {
 730         struct uio_device *idev = vma->vm_private_data;
 731         int mi = uio_find_mem_index(vma);
 732         struct uio_mem *mem;
 733
 734         if (mi < 0)
 735                 return -EINVAL;
 736         mem = idev->info->mem + mi;
 737
 738         if (mem->addr & ~PAGE_MASK)
 739                 return -ENODEV;
 740         if (vma->vm_end - vma->vm_start > mem->size)
 741                 return -EINVAL;
 742
 743         vma->vm_ops = &uio_physical_vm_ops;
 744         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 745
 746         /*
 747          * We cannot use the vm_iomap_memory() helper here,
 748          * because vma->vm_pgoff is the map index we looked
 749          * up above in uio_find_mem_index(), rather than an
 750          * actual page offset into the mmap.
 751          *
 752          * So we just do the physical mmap without a page
 753          * offset.
 754          */
 755         return remap_pfn_range(vma,
 756                                vma->vm_start,
 757                                mem->addr >> PAGE_SHIFT,
 758                                vma->vm_end - vma->vm_start,
 759                                vma->vm_page_prot);
 760 }
 761
 762 static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
 763 {
 764         struct uio_listener *listener = filep->private_data;
 765         struct uio_device *idev = listener->dev;
 766         int mi;
 767         unsigned long requested_pages, actual_pages;
 768         int ret = 0;
 769
 770         if (vma->vm_end < vma->vm_start)
 771                 return -EINVAL;
 772
 773         vma->vm_private_data = idev;
 774
 775         mutex_lock(&idev->info_lock);
 776         if (!idev->info) {
 777                 ret = -EINVAL;
 778                 goto out;
 779         }
 780
 781         mi = uio_find_mem_index(vma);
 782         if (mi < 0) {
 783                 ret = -EINVAL;
 784                 goto out;
 785         }
 786
 787         requested_pages = vma_pages(vma);
 788         actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
 789                         + idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
 790         if (requested_pages > actual_pages) {
 791                 ret = -EINVAL;
 792                 goto out;
 793         }
 794
 795         if (idev->info->mmap) {
 796                 ret = idev->info->mmap(idev->info, vma);
 797                 goto out;
 798         }
 799
 800         switch (idev->info->mem[mi].memtype) {
 801                 case UIO_MEM_PHYS:
 802                         ret = uio_mmap_physical(vma);
 803                         break;
 804                 case UIO_MEM_LOGICAL:
 805                 case UIO_MEM_VIRTUAL:
 806                         ret = uio_mmap_logical(vma);
 807                         break;
 808                 default:
 809                         ret = -EINVAL;
 810         }
 811
 812 out:
 813         mutex_unlock(&idev->info_lock);
 814         return 0;
 815 }
 816
 817 static const struct file_operations uio_fops = {
 818         .owner          = THIS_MODULE,
 819         .open           = uio_open,
 820         .release        = uio_release,
 821         .read           = uio_read,
 822         .write          = uio_write,
 823         .mmap           = uio_mmap,
 824         .poll           = uio_poll,
 825         .fasync         = uio_fasync,
 826         .llseek         = noop_llseek,
 827 };
 828
 829 static int uio_major_init(void)
 830 {
 831         static const char name[] = "uio";
 832         struct cdev *cdev = NULL;
 833         dev_t uio_dev = 0;
 834         int result;
 835
 836         result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name);
 837         if (result)
 838                 goto out;
 839
 840         result = -ENOMEM;
 841         cdev = cdev_alloc();
 842         if (!cdev)
 843                 goto out_unregister;
 844
 845         cdev->owner = THIS_MODULE;
 846         cdev->ops = &uio_fops;
 847         kobject_set_name(&cdev->kobj, "%s", name);
 848
 849         result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES);
 850         if (result)
 851                 goto out_put;
 852
 853         uio_major = MAJOR(uio_dev);
 854         uio_cdev = cdev;
 855         return 0;
 856 out_put:
 857         kobject_put(&cdev->kobj);
 858 out_unregister:
 859         unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
 860 out:
 861         return result;
 862 }
 863
 864 static void uio_major_cleanup(void)
 865 {
 866         unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
 867         cdev_del(uio_cdev);
 868 }
 869
 870 static int init_uio_class(void)
 871 {
 872         int ret;
 873
 874         /* This is the first time in here, set everything up properly */
 875         ret = uio_major_init();
 876         if (ret)
 877                 goto exit;
 878
 879         ret = class_register(&uio_class);
 880         if (ret) {
 881                 printk(KERN_ERR "class_register failed for uio\n");
 882                 goto err_class_register;
 883         }
 884         return 0;
 885
 886 err_class_register:
 887         uio_major_cleanup();
 888 exit:
 889         return ret;
 890 }
 891
 892 static void release_uio_class(void)
 893 {
 894         class_unregister(&uio_class);
 895         uio_major_cleanup();
 896 }
 897
 898 static void uio_device_release(struct device *dev)
 899 {
 900         struct uio_device *idev = dev_get_drvdata(dev);
 901
 902         kfree(idev);
 903 }
 904
 905 /**
 906  * uio_register_device - register a new userspace IO device
 907  * @owner:      module that creates the new device
 908  * @parent:     parent device
 909  * @info:       UIO device capabilities
 910  *
 911  * returns zero on success or a negative error code.
 912  */
 913 int __uio_register_device(struct module *owner,
 914                           struct device *parent,
 915                           struct uio_info *info)
 916 {
 917         struct uio_device *idev;
 918         int ret = 0;
 919
 920         if (!parent || !info || !info->name || !info->version)
 921                 return -EINVAL;
 922
 923         info->uio_dev = NULL;
 924
 925         idev = kzalloc(sizeof(*idev), GFP_KERNEL);
 926         if (!idev) {
 927                 return -ENOMEM;
 928         }
 929
 930         idev->owner = owner;
 931         idev->info = info;
 932         mutex_init(&idev->info_lock);
 933         init_waitqueue_head(&idev->wait);
 934         atomic_set(&idev->event, 0);
 935
 936         ret = uio_get_minor(idev);
 937         if (ret)
 938                 return ret;
 939
 940         idev->dev.devt = MKDEV(uio_major, idev->minor);
 941         idev->dev.class = &uio_class;
 942         idev->dev.parent = parent;
 943         idev->dev.release = uio_device_release;
 944         dev_set_drvdata(&idev->dev, idev);
 945
 946         ret = dev_set_name(&idev->dev, "uio%d", idev->minor);
 947         if (ret)
 948                 goto err_device_create;
 949
 950         ret = device_register(&idev->dev);
 951         if (ret)
 952                 goto err_device_create;
 953
 954         ret = uio_dev_add_attributes(idev);
 955         if (ret)
 956                 goto err_uio_dev_add_attributes;
 957
 958         info->uio_dev = idev;
 959
 960         if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) {
 961                 /*
 962                  * Note that we deliberately don't use devm_request_irq
 963                  * here. The parent module can unregister the UIO device
 964                  * and call pci_disable_msi, which requires that this
 965                  * irq has been freed. However, the device may have open
 966                  * FDs at the time of unregister and therefore may not be
 967                  * freed until they are released.
 968                  */
 969                 ret = request_irq(info->irq, uio_interrupt,
 970                                   info->irq_flags, info->name, idev);
 971                 if (ret)
 972                         goto err_request_irq;
 973         }
 974
 975         return 0;
 976
 977 err_request_irq:
 978         uio_dev_del_attributes(idev);
 979 err_uio_dev_add_attributes:
 980         device_unregister(&idev->dev);
 981 err_device_create:
 982         uio_free_minor(idev);
 983         return ret;
 984 }
 985 EXPORT_SYMBOL_GPL(__uio_register_device);
 986
 987 /**
 988  * uio_unregister_device - unregister a industrial IO device
 989  * @info:       UIO device capabilities
 990  *
 991  */
 992 void uio_unregister_device(struct uio_info *info)
 993 {
 994         struct uio_device *idev;
 995
 996         if (!info || !info->uio_dev)
 997                 return;
 998
 999         idev = info->uio_dev;
1000
1001         uio_free_minor(idev);
1002
1003         mutex_lock(&idev->info_lock);
1004         uio_dev_del_attributes(idev);
1005
1006         if (info->irq && info->irq != UIO_IRQ_CUSTOM)
1007                 free_irq(info->irq, idev);
1008
1009         idev->info = NULL;
1010         mutex_unlock(&idev->info_lock);
1011
1012         device_unregister(&idev->dev);
1013
1014         return;
1015 }
1016 EXPORT_SYMBOL_GPL(uio_unregister_device);
1017
1018 static int __init uio_init(void)
1019 {
1020         return init_uio_class();
1021 }
1022
1023 static void __exit uio_exit(void)
1024 {
1025         release_uio_class();
1026         idr_destroy(&uio_idr);
1027 }
1028
1029 module_init(uio_init)
1030 module_exit(uio_exit)
1031 MODULE_LICENSE("GPL v2");