drivers/uio/uio.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * drivers/uio/uio.c
   4  *
   5  * Copyright(C) 2005, Benedikt Spranger <b.spranger@linutronix.de>
   6  * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
   7  * Copyright(C) 2006, Hans J. Koch <hjk@hansjkoch.de>
   8  * Copyright(C) 2006, Greg Kroah-Hartman <greg@kroah.com>
   9  *
  10  * Userspace IO
  11  *
  12  * Base Functions
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/poll.h>
  18 #include <linux/device.h>
  19 #include <linux/slab.h>
  20 #include <linux/mm.h>
  21 #include <linux/idr.h>
  22 #include <linux/sched/signal.h>
  23 #include <linux/string.h>
  24 #include <linux/kobject.h>
  25 #include <linux/cdev.h>
  26 #include <linux/uio_driver.h>
  27
  28 #define UIO_MAX_DEVICES         (1U << MINORBITS)
  29
  30 static int uio_major;
  31 static struct cdev *uio_cdev;
  32 static DEFINE_IDR(uio_idr);
  33 static const struct file_operations uio_fops;
  34
  35 /* Protect idr accesses */
  36 static DEFINE_MUTEX(minor_lock);
  37
  38 /*
  39  * attributes
  40  */
  41
  42 struct uio_map {
  43         struct kobject kobj;
  44         struct uio_mem *mem;
  45 };
  46 #define to_map(map) container_of(map, struct uio_map, kobj)
  47
  48 static ssize_t map_name_show(struct uio_mem *mem, char *buf)
  49 {
  50         if (unlikely(!mem->name))
  51                 mem->name = "";
  52
  53         return sprintf(buf, "%s\n", mem->name);
  54 }
  55
  56 static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
  57 {
  58         return sprintf(buf, "%pa\n", &mem->addr);
  59 }
  60
  61 static ssize_t map_size_show(struct uio_mem *mem, char *buf)
  62 {
  63         return sprintf(buf, "%pa\n", &mem->size);
  64 }
  65
  66 static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
  67 {
  68         return sprintf(buf, "0x%llx\n", (unsigned long long)mem->offs);
  69 }
  70
  71 struct map_sysfs_entry {
  72         struct attribute attr;
  73         ssize_t (*show)(struct uio_mem *, char *);
  74         ssize_t (*store)(struct uio_mem *, const char *, size_t);
  75 };
  76
  77 static struct map_sysfs_entry name_attribute =
  78         __ATTR(name, S_IRUGO, map_name_show, NULL);
  79 static struct map_sysfs_entry addr_attribute =
  80         __ATTR(addr, S_IRUGO, map_addr_show, NULL);
  81 static struct map_sysfs_entry size_attribute =
  82         __ATTR(size, S_IRUGO, map_size_show, NULL);
  83 static struct map_sysfs_entry offset_attribute =
  84         __ATTR(offset, S_IRUGO, map_offset_show, NULL);
  85
  86 static struct attribute *attrs[] = {
  87         &name_attribute.attr,
  88         &addr_attribute.attr,
  89         &size_attribute.attr,
  90         &offset_attribute.attr,
  91         NULL,   /* need to NULL terminate the list of attributes */
  92 };
  93
  94 static void map_release(struct kobject *kobj)
  95 {
  96         struct uio_map *map = to_map(kobj);
  97         kfree(map);
  98 }
  99
 100 static ssize_t map_type_show(struct kobject *kobj, struct attribute *attr,
 101                              char *buf)
 102 {
 103         struct uio_map *map = to_map(kobj);
 104         struct uio_mem *mem = map->mem;
 105         struct map_sysfs_entry *entry;
 106
 107         entry = container_of(attr, struct map_sysfs_entry, attr);
 108
 109         if (!entry->show)
 110                 return -EIO;
 111
 112         return entry->show(mem, buf);
 113 }
 114
 115 static const struct sysfs_ops map_sysfs_ops = {
 116         .show = map_type_show,
 117 };
 118
 119 static struct kobj_type map_attr_type = {
 120         .release        = map_release,
 121         .sysfs_ops      = &map_sysfs_ops,
 122         .default_attrs  = attrs,
 123 };
 124
 125 struct uio_portio {
 126         struct kobject kobj;
 127         struct uio_port *port;
 128 };
 129 #define to_portio(portio) container_of(portio, struct uio_portio, kobj)
 130
 131 static ssize_t portio_name_show(struct uio_port *port, char *buf)
 132 {
 133         if (unlikely(!port->name))
 134                 port->name = "";
 135
 136         return sprintf(buf, "%s\n", port->name);
 137 }
 138
 139 static ssize_t portio_start_show(struct uio_port *port, char *buf)
 140 {
 141         return sprintf(buf, "0x%lx\n", port->start);
 142 }
 143
 144 static ssize_t portio_size_show(struct uio_port *port, char *buf)
 145 {
 146         return sprintf(buf, "0x%lx\n", port->size);
 147 }
 148
 149 static ssize_t portio_porttype_show(struct uio_port *port, char *buf)
 150 {
 151         const char *porttypes[] = {"none", "x86", "gpio", "other"};
 152
 153         if ((port->porttype < 0) || (port->porttype > UIO_PORT_OTHER))
 154                 return -EINVAL;
 155
 156         return sprintf(buf, "port_%s\n", porttypes[port->porttype]);
 157 }
 158
 159 struct portio_sysfs_entry {
 160         struct attribute attr;
 161         ssize_t (*show)(struct uio_port *, char *);
 162         ssize_t (*store)(struct uio_port *, const char *, size_t);
 163 };
 164
 165 static struct portio_sysfs_entry portio_name_attribute =
 166         __ATTR(name, S_IRUGO, portio_name_show, NULL);
 167 static struct portio_sysfs_entry portio_start_attribute =
 168         __ATTR(start, S_IRUGO, portio_start_show, NULL);
 169 static struct portio_sysfs_entry portio_size_attribute =
 170         __ATTR(size, S_IRUGO, portio_size_show, NULL);
 171 static struct portio_sysfs_entry portio_porttype_attribute =
 172         __ATTR(porttype, S_IRUGO, portio_porttype_show, NULL);
 173
 174 static struct attribute *portio_attrs[] = {
 175         &portio_name_attribute.attr,
 176         &portio_start_attribute.attr,
 177         &portio_size_attribute.attr,
 178         &portio_porttype_attribute.attr,
 179         NULL,
 180 };
 181
 182 static void portio_release(struct kobject *kobj)
 183 {
 184         struct uio_portio *portio = to_portio(kobj);
 185         kfree(portio);
 186 }
 187
 188 static ssize_t portio_type_show(struct kobject *kobj, struct attribute *attr,
 189                              char *buf)
 190 {
 191         struct uio_portio *portio = to_portio(kobj);
 192         struct uio_port *port = portio->port;
 193         struct portio_sysfs_entry *entry;
 194
 195         entry = container_of(attr, struct portio_sysfs_entry, attr);
 196
 197         if (!entry->show)
 198                 return -EIO;
 199
 200         return entry->show(port, buf);
 201 }
 202
 203 static const struct sysfs_ops portio_sysfs_ops = {
 204         .show = portio_type_show,
 205 };
 206
 207 static struct kobj_type portio_attr_type = {
 208         .release        = portio_release,
 209         .sysfs_ops      = &portio_sysfs_ops,
 210         .default_attrs  = portio_attrs,
 211 };
 212
 213 static ssize_t name_show(struct device *dev,
 214                          struct device_attribute *attr, char *buf)
 215 {
 216         struct uio_device *idev = dev_get_drvdata(dev);
 217         int ret;
 218
 219         mutex_lock(&idev->info_lock);
 220         if (!idev->info) {
 221                 ret = -EINVAL;
 222                 dev_err(dev, "the device has been unregistered\n");
 223                 goto out;
 224         }
 225
 226         ret = sprintf(buf, "%s\n", idev->info->name);
 227
 228 out:
 229         mutex_unlock(&idev->info_lock);
 230         return ret;
 231 }
 232 static DEVICE_ATTR_RO(name);
 233
 234 static ssize_t version_show(struct device *dev,
 235                             struct device_attribute *attr, char *buf)
 236 {
 237         struct uio_device *idev = dev_get_drvdata(dev);
 238         int ret;
 239
 240         mutex_lock(&idev->info_lock);
 241         if (!idev->info) {
 242                 ret = -EINVAL;
 243                 dev_err(dev, "the device has been unregistered\n");
 244                 goto out;
 245         }
 246
 247         ret = sprintf(buf, "%s\n", idev->info->version);
 248
 249 out:
 250         mutex_unlock(&idev->info_lock);
 251         return ret;
 252 }
 253 static DEVICE_ATTR_RO(version);
 254
 255 static ssize_t event_show(struct device *dev,
 256                           struct device_attribute *attr, char *buf)
 257 {
 258         struct uio_device *idev = dev_get_drvdata(dev);
 259         return sprintf(buf, "%u\n", (unsigned int)atomic_read(&idev->event));
 260 }
 261 static DEVICE_ATTR_RO(event);
 262
 263 static struct attribute *uio_attrs[] = {
 264         &dev_attr_name.attr,
 265         &dev_attr_version.attr,
 266         &dev_attr_event.attr,
 267         NULL,
 268 };
 269 ATTRIBUTE_GROUPS(uio);
 270
 271 /* UIO class infrastructure */
 272 static struct class uio_class = {
 273         .name = "uio",
 274         .dev_groups = uio_groups,
 275 };
 276
 277 static bool uio_class_registered;
 278
 279 /*
 280  * device functions
 281  */
 282 static int uio_dev_add_attributes(struct uio_device *idev)
 283 {
 284         int ret;
 285         int mi, pi;
 286         int map_found = 0;
 287         int portio_found = 0;
 288         struct uio_mem *mem;
 289         struct uio_map *map;
 290         struct uio_port *port;
 291         struct uio_portio *portio;
 292
 293         for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
 294                 mem = &idev->info->mem[mi];
 295                 if (mem->size == 0)
 296                         break;
 297                 if (!map_found) {
 298                         map_found = 1;
 299                         idev->map_dir = kobject_create_and_add("maps",
 300                                                         &idev->dev.kobj);
 301                         if (!idev->map_dir) {
 302                                 ret = -ENOMEM;
 303                                 goto err_map;
 304                         }
 305                 }
 306                 map = kzalloc(sizeof(*map), GFP_KERNEL);
 307                 if (!map) {
 308                         ret = -ENOMEM;
 309                         goto err_map;
 310                 }
 311                 kobject_init(&map->kobj, &map_attr_type);
 312                 map->mem = mem;
 313                 mem->map = map;
 314                 ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
 315                 if (ret)
 316                         goto err_map_kobj;
 317                 ret = kobject_uevent(&map->kobj, KOBJ_ADD);
 318                 if (ret)
 319                         goto err_map_kobj;
 320         }
 321
 322         for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
 323                 port = &idev->info->port[pi];
 324                 if (port->size == 0)
 325                         break;
 326                 if (!portio_found) {
 327                         portio_found = 1;
 328                         idev->portio_dir = kobject_create_and_add("portio",
 329                                                         &idev->dev.kobj);
 330                         if (!idev->portio_dir) {
 331                                 ret = -ENOMEM;
 332                                 goto err_portio;
 333                         }
 334                 }
 335                 portio = kzalloc(sizeof(*portio), GFP_KERNEL);
 336                 if (!portio) {
 337                         ret = -ENOMEM;
 338                         goto err_portio;
 339                 }
 340                 kobject_init(&portio->kobj, &portio_attr_type);
 341                 portio->port = port;
 342                 port->portio = portio;
 343                 ret = kobject_add(&portio->kobj, idev->portio_dir,
 344                                                         "port%d", pi);
 345                 if (ret)
 346                         goto err_portio_kobj;
 347                 ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
 348                 if (ret)
 349                         goto err_portio_kobj;
 350         }
 351
 352         return 0;
 353
 354 err_portio:
 355         pi--;
 356 err_portio_kobj:
 357         for (; pi >= 0; pi--) {
 358                 port = &idev->info->port[pi];
 359                 portio = port->portio;
 360                 kobject_put(&portio->kobj);
 361         }
 362         kobject_put(idev->portio_dir);
 363 err_map:
 364         mi--;
 365 err_map_kobj:
 366         for (; mi >= 0; mi--) {
 367                 mem = &idev->info->mem[mi];
 368                 map = mem->map;
 369                 kobject_put(&map->kobj);
 370         }
 371         kobject_put(idev->map_dir);
 372         dev_err(&idev->dev, "error creating sysfs files (%d)\n", ret);
 373         return ret;
 374 }
 375
 376 static void uio_dev_del_attributes(struct uio_device *idev)
 377 {
 378         int i;
 379         struct uio_mem *mem;
 380         struct uio_port *port;
 381
 382         for (i = 0; i < MAX_UIO_MAPS; i++) {
 383                 mem = &idev->info->mem[i];
 384                 if (mem->size == 0)
 385                         break;
 386                 kobject_put(&mem->map->kobj);
 387         }
 388         kobject_put(idev->map_dir);
 389
 390         for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
 391                 port = &idev->info->port[i];
 392                 if (port->size == 0)
 393                         break;
 394                 kobject_put(&port->portio->kobj);
 395         }
 396         kobject_put(idev->portio_dir);
 397 }
 398
 399 static int uio_get_minor(struct uio_device *idev)
 400 {
 401         int retval = -ENOMEM;
 402
 403         mutex_lock(&minor_lock);
 404         retval = idr_alloc(&uio_idr, idev, 0, UIO_MAX_DEVICES, GFP_KERNEL);
 405         if (retval >= 0) {
 406                 idev->minor = retval;
 407                 retval = 0;
 408         } else if (retval == -ENOSPC) {
 409                 dev_err(&idev->dev, "too many uio devices\n");
 410                 retval = -EINVAL;
 411         }
 412         mutex_unlock(&minor_lock);
 413         return retval;
 414 }
 415
 416 static void uio_free_minor(unsigned long minor)
 417 {
 418         mutex_lock(&minor_lock);
 419         idr_remove(&uio_idr, minor);
 420         mutex_unlock(&minor_lock);
 421 }
 422
 423 /**
 424  * uio_event_notify - trigger an interrupt event
 425  * @info: UIO device capabilities
 426  */
 427 void uio_event_notify(struct uio_info *info)
 428 {
 429         struct uio_device *idev = info->uio_dev;
 430
 431         atomic_inc(&idev->event);
 432         wake_up_interruptible(&idev->wait);
 433         kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
 434 }
 435 EXPORT_SYMBOL_GPL(uio_event_notify);
 436
 437 /**
 438  * uio_interrupt - hardware interrupt handler
 439  * @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
 440  * @dev_id: Pointer to the devices uio_device structure
 441  */
 442 static irqreturn_t uio_interrupt(int irq, void *dev_id)
 443 {
 444         struct uio_device *idev = (struct uio_device *)dev_id;
 445         irqreturn_t ret;
 446
 447         ret = idev->info->handler(irq, idev->info);
 448         if (ret == IRQ_HANDLED)
 449                 uio_event_notify(idev->info);
 450
 451         return ret;
 452 }
 453
 454 struct uio_listener {
 455         struct uio_device *dev;
 456         s32 event_count;
 457 };
 458
 459 static int uio_open(struct inode *inode, struct file *filep)
 460 {
 461         struct uio_device *idev;
 462         struct uio_listener *listener;
 463         int ret = 0;
 464
 465         mutex_lock(&minor_lock);
 466         idev = idr_find(&uio_idr, iminor(inode));
 467         mutex_unlock(&minor_lock);
 468         if (!idev) {
 469                 ret = -ENODEV;
 470                 goto out;
 471         }
 472
 473         get_device(&idev->dev);
 474
 475         if (!try_module_get(idev->owner)) {
 476                 ret = -ENODEV;
 477                 goto err_module_get;
 478         }
 479
 480         listener = kmalloc(sizeof(*listener), GFP_KERNEL);
 481         if (!listener) {
 482                 ret = -ENOMEM;
 483                 goto err_alloc_listener;
 484         }
 485
 486         listener->dev = idev;
 487         listener->event_count = atomic_read(&idev->event);
 488         filep->private_data = listener;
 489
 490         mutex_lock(&idev->info_lock);
 491         if (!idev->info) {
 492                 mutex_unlock(&idev->info_lock);
 493                 ret = -EINVAL;
 494                 goto err_infoopen;
 495         }
 496
 497         if (idev->info->open)
 498                 ret = idev->info->open(idev->info, inode);
 499         mutex_unlock(&idev->info_lock);
 500         if (ret)
 501                 goto err_infoopen;
 502
 503         return 0;
 504
 505 err_infoopen:
 506         kfree(listener);
 507
 508 err_alloc_listener:
 509         module_put(idev->owner);
 510
 511 err_module_get:
 512         put_device(&idev->dev);
 513
 514 out:
 515         return ret;
 516 }
 517
 518 static int uio_fasync(int fd, struct file *filep, int on)
 519 {
 520         struct uio_listener *listener = filep->private_data;
 521         struct uio_device *idev = listener->dev;
 522
 523         return fasync_helper(fd, filep, on, &idev->async_queue);
 524 }
 525
 526 static int uio_release(struct inode *inode, struct file *filep)
 527 {
 528         int ret = 0;
 529         struct uio_listener *listener = filep->private_data;
 530         struct uio_device *idev = listener->dev;
 531
 532         mutex_lock(&idev->info_lock);
 533         if (idev->info && idev->info->release)
 534                 ret = idev->info->release(idev->info, inode);
 535         mutex_unlock(&idev->info_lock);
 536
 537         module_put(idev->owner);
 538         kfree(listener);
 539         put_device(&idev->dev);
 540         return ret;
 541 }
 542
 543 static __poll_t uio_poll(struct file *filep, poll_table *wait)
 544 {
 545         struct uio_listener *listener = filep->private_data;
 546         struct uio_device *idev = listener->dev;
 547         __poll_t ret = 0;
 548
 549         mutex_lock(&idev->info_lock);
 550         if (!idev->info || !idev->info->irq)
 551                 ret = -EIO;
 552         mutex_unlock(&idev->info_lock);
 553
 554         if (ret)
 555                 return ret;
 556
 557         poll_wait(filep, &idev->wait, wait);
 558         if (listener->event_count != atomic_read(&idev->event))
 559                 return EPOLLIN | EPOLLRDNORM;
 560         return 0;
 561 }
 562
 563 static ssize_t uio_read(struct file *filep, char __user *buf,
 564                         size_t count, loff_t *ppos)
 565 {
 566         struct uio_listener *listener = filep->private_data;
 567         struct uio_device *idev = listener->dev;
 568         DECLARE_WAITQUEUE(wait, current);
 569         ssize_t retval = 0;
 570         s32 event_count;
 571
 572         if (count != sizeof(s32))
 573                 return -EINVAL;
 574
 575         add_wait_queue(&idev->wait, &wait);
 576
 577         do {
 578                 mutex_lock(&idev->info_lock);
 579                 if (!idev->info || !idev->info->irq) {
 580                         retval = -EIO;
 581                         mutex_unlock(&idev->info_lock);
 582                         break;
 583                 }
 584                 mutex_unlock(&idev->info_lock);
 585
 586                 set_current_state(TASK_INTERRUPTIBLE);
 587
 588                 event_count = atomic_read(&idev->event);
 589                 if (event_count != listener->event_count) {
 590                         __set_current_state(TASK_RUNNING);
 591                         if (copy_to_user(buf, &event_count, count))
 592                                 retval = -EFAULT;
 593                         else {
 594                                 listener->event_count = event_count;
 595                                 retval = count;
 596                         }
 597                         break;
 598                 }
 599
 600                 if (filep->f_flags & O_NONBLOCK) {
 601                         retval = -EAGAIN;
 602                         break;
 603                 }
 604
 605                 if (signal_pending(current)) {
 606                         retval = -ERESTARTSYS;
 607                         break;
 608                 }
 609                 schedule();
 610         } while (1);
 611
 612         __set_current_state(TASK_RUNNING);
 613         remove_wait_queue(&idev->wait, &wait);
 614
 615         return retval;
 616 }
 617
 618 static ssize_t uio_write(struct file *filep, const char __user *buf,
 619                         size_t count, loff_t *ppos)
 620 {
 621         struct uio_listener *listener = filep->private_data;
 622         struct uio_device *idev = listener->dev;
 623         ssize_t retval;
 624         s32 irq_on;
 625
 626         if (count != sizeof(s32))
 627                 return -EINVAL;
 628
 629         if (copy_from_user(&irq_on, buf, count))
 630                 return -EFAULT;
 631
 632         mutex_lock(&idev->info_lock);
 633         if (!idev->info) {
 634                 retval = -EINVAL;
 635                 goto out;
 636         }
 637
 638         if (!idev->info->irq) {
 639                 retval = -EIO;
 640                 goto out;
 641         }
 642
 643         if (!idev->info->irqcontrol) {
 644                 retval = -ENOSYS;
 645                 goto out;
 646         }
 647
 648         retval = idev->info->irqcontrol(idev->info, irq_on);
 649
 650 out:
 651         mutex_unlock(&idev->info_lock);
 652         return retval ? retval : sizeof(s32);
 653 }
 654
 655 static int uio_find_mem_index(struct vm_area_struct *vma)
 656 {
 657         struct uio_device *idev = vma->vm_private_data;
 658
 659         if (vma->vm_pgoff < MAX_UIO_MAPS) {
 660                 if (idev->info->mem[vma->vm_pgoff].size == 0)
 661                         return -1;
 662                 return (int)vma->vm_pgoff;
 663         }
 664         return -1;
 665 }
 666
 667 static vm_fault_t uio_vma_fault(struct vm_fault *vmf)
 668 {
 669         struct uio_device *idev = vmf->vma->vm_private_data;
 670         struct page *page;
 671         unsigned long offset;
 672         void *addr;
 673         vm_fault_t ret = 0;
 674         int mi;
 675
 676         mutex_lock(&idev->info_lock);
 677         if (!idev->info) {
 678                 ret = VM_FAULT_SIGBUS;
 679                 goto out;
 680         }
 681
 682         mi = uio_find_mem_index(vmf->vma);
 683         if (mi < 0) {
 684                 ret = VM_FAULT_SIGBUS;
 685                 goto out;
 686         }
 687
 688         /*
 689          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
 690          * to use mem[N].
 691          */
 692         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
 693
 694         addr = (void *)(unsigned long)idev->info->mem[mi].addr + offset;
 695         if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
 696                 page = virt_to_page(addr);
 697         else
 698                 page = vmalloc_to_page(addr);
 699         get_page(page);
 700         vmf->page = page;
 701
 702 out:
 703         mutex_unlock(&idev->info_lock);
 704
 705         return ret;
 706 }
 707
 708 static const struct vm_operations_struct uio_logical_vm_ops = {
 709         .fault = uio_vma_fault,
 710 };
 711
 712 static int uio_mmap_logical(struct vm_area_struct *vma)
 713 {
 714         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
 715         vma->vm_ops = &uio_logical_vm_ops;
 716         return 0;
 717 }
 718
 719 static const struct vm_operations_struct uio_physical_vm_ops = {
 720 #ifdef CONFIG_HAVE_IOREMAP_PROT
 721         .access = generic_access_phys,
 722 #endif
 723 };
 724
 725 static int uio_mmap_physical(struct vm_area_struct *vma)
 726 {
 727         struct uio_device *idev = vma->vm_private_data;
 728         int mi = uio_find_mem_index(vma);
 729         struct uio_mem *mem;
 730
 731         if (mi < 0)
 732                 return -EINVAL;
 733         mem = idev->info->mem + mi;
 734
 735         if (mem->addr & ~PAGE_MASK)
 736                 return -ENODEV;
 737         if (vma->vm_end - vma->vm_start > mem->size)
 738                 return -EINVAL;
 739
 740         vma->vm_ops = &uio_physical_vm_ops;
 741         if (idev->info->mem[mi].memtype == UIO_MEM_PHYS)
 742                 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 743
 744         /*
 745          * We cannot use the vm_iomap_memory() helper here,
 746          * because vma->vm_pgoff is the map index we looked
 747          * up above in uio_find_mem_index(), rather than an
 748          * actual page offset into the mmap.
 749          *
 750          * So we just do the physical mmap without a page
 751          * offset.
 752          */
 753         return remap_pfn_range(vma,
 754                                vma->vm_start,
 755                                mem->addr >> PAGE_SHIFT,
 756                                vma->vm_end - vma->vm_start,
 757                                vma->vm_page_prot);
 758 }
 759
 760 static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
 761 {
 762         struct uio_listener *listener = filep->private_data;
 763         struct uio_device *idev = listener->dev;
 764         int mi;
 765         unsigned long requested_pages, actual_pages;
 766         int ret = 0;
 767
 768         if (vma->vm_end < vma->vm_start)
 769                 return -EINVAL;
 770
 771         vma->vm_private_data = idev;
 772
 773         mutex_lock(&idev->info_lock);
 774         if (!idev->info) {
 775                 ret = -EINVAL;
 776                 goto out;
 777         }
 778
 779         mi = uio_find_mem_index(vma);
 780         if (mi < 0) {
 781                 ret = -EINVAL;
 782                 goto out;
 783         }
 784
 785         requested_pages = vma_pages(vma);
 786         actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
 787                         + idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
 788         if (requested_pages > actual_pages) {
 789                 ret = -EINVAL;
 790                 goto out;
 791         }
 792
 793         if (idev->info->mmap) {
 794                 ret = idev->info->mmap(idev->info, vma);
 795                 goto out;
 796         }
 797
 798         switch (idev->info->mem[mi].memtype) {
 799         case UIO_MEM_IOVA:
 800         case UIO_MEM_PHYS:
 801                 ret = uio_mmap_physical(vma);
 802                 break;
 803         case UIO_MEM_LOGICAL:
 804         case UIO_MEM_VIRTUAL:
 805                 ret = uio_mmap_logical(vma);
 806                 break;
 807         default:
 808                 ret = -EINVAL;
 809         }
 810
 811  out:
 812         mutex_unlock(&idev->info_lock);
 813         return ret;
 814 }
 815
 816 static const struct file_operations uio_fops = {
 817         .owner          = THIS_MODULE,
 818         .open           = uio_open,
 819         .release        = uio_release,
 820         .read           = uio_read,
 821         .write          = uio_write,
 822         .mmap           = uio_mmap,
 823         .poll           = uio_poll,
 824         .fasync         = uio_fasync,
 825         .llseek         = noop_llseek,
 826 };
 827
 828 static int uio_major_init(void)
 829 {
 830         static const char name[] = "uio";
 831         struct cdev *cdev = NULL;
 832         dev_t uio_dev = 0;
 833         int result;
 834
 835         result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name);
 836         if (result)
 837                 goto out;
 838
 839         result = -ENOMEM;
 840         cdev = cdev_alloc();
 841         if (!cdev)
 842                 goto out_unregister;
 843
 844         cdev->owner = THIS_MODULE;
 845         cdev->ops = &uio_fops;
 846         kobject_set_name(&cdev->kobj, "%s", name);
 847
 848         result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES);
 849         if (result)
 850                 goto out_put;
 851
 852         uio_major = MAJOR(uio_dev);
 853         uio_cdev = cdev;
 854         return 0;
 855 out_put:
 856         kobject_put(&cdev->kobj);
 857 out_unregister:
 858         unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
 859 out:
 860         return result;
 861 }
 862
 863 static void uio_major_cleanup(void)
 864 {
 865         unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
 866         cdev_del(uio_cdev);
 867 }
 868
 869 static int init_uio_class(void)
 870 {
 871         int ret;
 872
 873         /* This is the first time in here, set everything up properly */
 874         ret = uio_major_init();
 875         if (ret)
 876                 goto exit;
 877
 878         ret = class_register(&uio_class);
 879         if (ret) {
 880                 printk(KERN_ERR "class_register failed for uio\n");
 881                 goto err_class_register;
 882         }
 883
 884         uio_class_registered = true;
 885
 886         return 0;
 887
 888 err_class_register:
 889         uio_major_cleanup();
 890 exit:
 891         return ret;
 892 }
 893
 894 static void release_uio_class(void)
 895 {
 896         uio_class_registered = false;
 897         class_unregister(&uio_class);
 898         uio_major_cleanup();
 899 }
 900
 901 static void uio_device_release(struct device *dev)
 902 {
 903         struct uio_device *idev = dev_get_drvdata(dev);
 904
 905         kfree(idev);
 906 }
 907
 908 /**
 909  * uio_register_device - register a new userspace IO device
 910  * @owner:      module that creates the new device
 911  * @parent:     parent device
 912  * @info:       UIO device capabilities
 913  *
 914  * returns zero on success or a negative error code.
 915  */
 916 int __uio_register_device(struct module *owner,
 917                           struct device *parent,
 918                           struct uio_info *info)
 919 {
 920         struct uio_device *idev;
 921         int ret = 0;
 922
 923         if (!uio_class_registered)
 924                 return -EPROBE_DEFER;
 925
 926         if (!parent || !info || !info->name || !info->version)
 927                 return -EINVAL;
 928
 929         info->uio_dev = NULL;
 930
 931         idev = kzalloc(sizeof(*idev), GFP_KERNEL);
 932         if (!idev) {
 933                 return -ENOMEM;
 934         }
 935
 936         idev->owner = owner;
 937         idev->info = info;
 938         mutex_init(&idev->info_lock);
 939         init_waitqueue_head(&idev->wait);
 940         atomic_set(&idev->event, 0);
 941
 942         ret = uio_get_minor(idev);
 943         if (ret) {
 944                 kfree(idev);
 945                 return ret;
 946         }
 947
 948         device_initialize(&idev->dev);
 949         idev->dev.devt = MKDEV(uio_major, idev->minor);
 950         idev->dev.class = &uio_class;
 951         idev->dev.parent = parent;
 952         idev->dev.release = uio_device_release;
 953         dev_set_drvdata(&idev->dev, idev);
 954
 955         ret = dev_set_name(&idev->dev, "uio%d", idev->minor);
 956         if (ret)
 957                 goto err_device_create;
 958
 959         ret = device_add(&idev->dev);
 960         if (ret)
 961                 goto err_device_create;
 962
 963         ret = uio_dev_add_attributes(idev);
 964         if (ret)
 965                 goto err_uio_dev_add_attributes;
 966
 967         info->uio_dev = idev;
 968
 969         if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) {
 970                 /*
 971                  * Note that we deliberately don't use devm_request_irq
 972                  * here. The parent module can unregister the UIO device
 973                  * and call pci_disable_msi, which requires that this
 974                  * irq has been freed. However, the device may have open
 975                  * FDs at the time of unregister and therefore may not be
 976                  * freed until they are released.
 977                  */
 978                 ret = request_irq(info->irq, uio_interrupt,
 979                                   info->irq_flags, info->name, idev);
 980                 if (ret) {
 981                         info->uio_dev = NULL;
 982                         goto err_request_irq;
 983                 }
 984         }
 985
 986         return 0;
 987
 988 err_request_irq:
 989         uio_dev_del_attributes(idev);
 990 err_uio_dev_add_attributes:
 991         device_del(&idev->dev);
 992 err_device_create:
 993         uio_free_minor(idev->minor);
 994         put_device(&idev->dev);
 995         return ret;
 996 }
 997 EXPORT_SYMBOL_GPL(__uio_register_device);
 998
 999 /**
1000  * uio_unregister_device - unregister a industrial IO device
1001  * @info:       UIO device capabilities
1002  *
1003  */
1004 void uio_unregister_device(struct uio_info *info)
1005 {
1006         struct uio_device *idev;
1007         unsigned long minor;
1008
1009         if (!info || !info->uio_dev)
1010                 return;
1011
1012         idev = info->uio_dev;
1013         minor = idev->minor;
1014
1015         mutex_lock(&idev->info_lock);
1016         uio_dev_del_attributes(idev);
1017
1018         if (info->irq && info->irq != UIO_IRQ_CUSTOM)
1019                 free_irq(info->irq, idev);
1020
1021         idev->info = NULL;
1022         mutex_unlock(&idev->info_lock);
1023
1024         wake_up_interruptible(&idev->wait);
1025         kill_fasync(&idev->async_queue, SIGIO, POLL_HUP);
1026
1027         device_unregister(&idev->dev);
1028
1029         uio_free_minor(minor);
1030
1031         return;
1032 }
1033 EXPORT_SYMBOL_GPL(uio_unregister_device);
1034
1035 static int __init uio_init(void)
1036 {
1037         return init_uio_class();
1038 }
1039
1040 static void __exit uio_exit(void)
1041 {
1042         release_uio_class();
1043         idr_destroy(&uio_idr);
1044 }
1045
1046 module_init(uio_init)
1047 module_exit(uio_exit)
1048 MODULE_LICENSE("GPL v2");