drivers/virtio/virtio_mmio.c

   1 /*
   2  * Virtio memory mapped device driver
   3  *
   4  * Copyright 2011, ARM Ltd.
   5  *
   6  * This module allows virtio devices to be used over a virtual, memory mapped
   7  * platform device.
   8  *
   9  * The guest device(s) may be instantiated in one of three equivalent ways:
  10  *
  11  * 1. Static platform device in board's code, eg.:
  12  *
  13  *      static struct platform_device v2m_virtio_device = {
  14  *              .name = "virtio-mmio",
  15  *              .id = -1,
  16  *              .num_resources = 2,
  17  *              .resource = (struct resource []) {
  18  *                      {
  19  *                              .start = 0x1001e000,
  20  *                              .end = 0x1001e0ff,
  21  *                              .flags = IORESOURCE_MEM,
  22  *                      }, {
  23  *                              .start = 42 + 32,
  24  *                              .end = 42 + 32,
  25  *                              .flags = IORESOURCE_IRQ,
  26  *                      },
  27  *              }
  28  *      };
  29  *
  30  * 2. Device Tree node, eg.:
  31  *
  32  *              virtio_block@1e000 {
  33  *                      compatible = "virtio,mmio";
  34  *                      reg = <0x1e000 0x100>;
  35  *                      interrupts = <42>;
  36  *              }
  37  *
  38  * 3. Kernel module (or command line) parameter. Can be used more than once -
  39  *    one device will be created for each one. Syntax:
  40  *
  41  *              [virtio_mmio.]device=<size>@<baseaddr>:<irq>[:<id>]
  42  *    where:
  43  *              <size>     := size (can use standard suffixes like K, M or G)
  44  *              <baseaddr> := physical base address
  45  *              <irq>      := interrupt number (as passed to request_irq())
  46  *              <id>       := (optional) platform device id
  47  *    eg.:
  48  *              virtio_mmio.device=0x100@0x100b0000:48 \
  49  *                              virtio_mmio.device=1K@0x1001e000:74
  50  *
  51  *
  52  *
  53  * Registers layout (all 32-bit wide):
  54  *
  55  * offset d. name             description
  56  * ------ -- ---------------- -----------------
  57  *
  58  * 0x000  R  MagicValue       Magic value "virt"
  59  * 0x004  R  Version          Device version (current max. 1)
  60  * 0x008  R  DeviceID         Virtio device ID
  61  * 0x00c  R  VendorID         Virtio vendor ID
  62  *
  63  * 0x010  R  HostFeatures     Features supported by the host
  64  * 0x014  W  HostFeaturesSel  Set of host features to access via HostFeatures
  65  *
  66  * 0x020  W  GuestFeatures    Features activated by the guest
  67  * 0x024  W  GuestFeaturesSel Set of activated features to set via GuestFeatures
  68  * 0x028  W  GuestPageSize    Size of guest's memory page in bytes
  69  *
  70  * 0x030  W  QueueSel         Queue selector
  71  * 0x034  R  QueueNumMax      Maximum size of the currently selected queue
  72  * 0x038  W  QueueNum         Queue size for the currently selected queue
  73  * 0x03c  W  QueueAlign       Used Ring alignment for the current queue
  74  * 0x040  RW QueuePFN         PFN for the currently selected queue
  75  *
  76  * 0x050  W  QueueNotify      Queue notifier
  77  * 0x060  R  InterruptStatus  Interrupt status register
  78  * 0x060  W  InterruptACK     Interrupt acknowledge register
  79  * 0x070  RW Status           Device status register
  80  *
  81  * 0x100+ RW                  Device-specific configuration space
  82  *
  83  * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
  84  *
  85  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  86  * See the COPYING file in the top-level directory.
  87  */
  88
  89 #define pr_fmt(fmt) "virtio-mmio: " fmt
  90
  91 #include <linux/highmem.h>
  92 #include <linux/interrupt.h>
  93 #include <linux/io.h>
  94 #include <linux/list.h>
  95 #include <linux/module.h>
  96 #include <linux/platform_device.h>
  97 #include <linux/slab.h>
  98 #include <linux/spinlock.h>
  99 #include <linux/virtio.h>
 100 #include <linux/virtio_config.h>
 101 #include <linux/virtio_mmio.h>
 102 #include <linux/virtio_ring.h>
 103
 104
 105
 106 /* The alignment to use between consumer and producer parts of vring.
 107  * Currently hardcoded to the page size. */
 108 #define VIRTIO_MMIO_VRING_ALIGN         PAGE_SIZE
 109
 110
 111
 112 #define to_virtio_mmio_device(_plat_dev) \
 113         container_of(_plat_dev, struct virtio_mmio_device, vdev)
 114
 115 struct virtio_mmio_device {
 116         struct virtio_device vdev;
 117         struct platform_device *pdev;
 118
 119         void __iomem *base;
 120         unsigned long version;
 121
 122         /* a list of queues so we can dispatch IRQs */
 123         spinlock_t lock;
 124         struct list_head virtqueues;
 125 };
 126
 127 struct virtio_mmio_vq_info {
 128         /* the actual virtqueue */
 129         struct virtqueue *vq;
 130
 131         /* the number of entries in the queue */
 132         unsigned int num;
 133
 134         /* the index of the queue */
 135         int queue_index;
 136
 137         /* the virtual address of the ring queue */
 138         void *queue;
 139
 140         /* the list node for the virtqueues list */
 141         struct list_head node;
 142 };
 143
 144
 145
 146 /* Configuration interface */
 147
 148 static u32 vm_get_features(struct virtio_device *vdev)
 149 {
 150         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 151
 152         /* TODO: Features > 32 bits */
 153         writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL);
 154
 155         return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
 156 }
 157
 158 static void vm_finalize_features(struct virtio_device *vdev)
 159 {
 160         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 161         int i;
 162
 163         /* Give virtio_ring a chance to accept features. */
 164         vring_transport_features(vdev);
 165
 166         for (i = 0; i < ARRAY_SIZE(vdev->features); i++) {
 167                 writel(i, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
 168                 writel(vdev->features[i],
 169                                 vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
 170         }
 171 }
 172
 173 static void vm_get(struct virtio_device *vdev, unsigned offset,
 174                    void *buf, unsigned len)
 175 {
 176         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 177         u8 *ptr = buf;
 178         int i;
 179
 180         for (i = 0; i < len; i++)
 181                 ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
 182 }
 183
 184 static void vm_set(struct virtio_device *vdev, unsigned offset,
 185                    const void *buf, unsigned len)
 186 {
 187         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 188         const u8 *ptr = buf;
 189         int i;
 190
 191         for (i = 0; i < len; i++)
 192                 writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
 193 }
 194
 195 static u8 vm_get_status(struct virtio_device *vdev)
 196 {
 197         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 198
 199         return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
 200 }
 201
 202 static void vm_set_status(struct virtio_device *vdev, u8 status)
 203 {
 204         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 205
 206         /* We should never be setting status to 0. */
 207         BUG_ON(status == 0);
 208
 209         writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
 210 }
 211
 212 static void vm_reset(struct virtio_device *vdev)
 213 {
 214         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 215
 216         /* 0 status means a reset. */
 217         writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
 218 }
 219
 220
 221
 222 /* Transport interface */
 223
 224 /* the notify function used when creating a virt queue */
 225 static void vm_notify(struct virtqueue *vq)
 226 {
 227         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
 228         struct virtio_mmio_vq_info *info = vq->priv;
 229
 230         /* We write the queue's selector into the notification register to
 231          * signal the other end */
 232         writel(info->queue_index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
 233 }
 234
 235 /* Notify all virtqueues on an interrupt. */
 236 static irqreturn_t vm_interrupt(int irq, void *opaque)
 237 {
 238         struct virtio_mmio_device *vm_dev = opaque;
 239         struct virtio_mmio_vq_info *info;
 240         struct virtio_driver *vdrv = container_of(vm_dev->vdev.dev.driver,
 241                         struct virtio_driver, driver);
 242         unsigned long status;
 243         unsigned long flags;
 244         irqreturn_t ret = IRQ_NONE;
 245
 246         /* Read and acknowledge interrupts */
 247         status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
 248         writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
 249
 250         if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)
 251                         && vdrv && vdrv->config_changed) {
 252                 vdrv->config_changed(&vm_dev->vdev);
 253                 ret = IRQ_HANDLED;
 254         }
 255
 256         if (likely(status & VIRTIO_MMIO_INT_VRING)) {
 257                 spin_lock_irqsave(&vm_dev->lock, flags);
 258                 list_for_each_entry(info, &vm_dev->virtqueues, node)
 259                         ret |= vring_interrupt(irq, info->vq);
 260                 spin_unlock_irqrestore(&vm_dev->lock, flags);
 261         }
 262
 263         return ret;
 264 }
 265
 266
 267
 268 static void vm_del_vq(struct virtqueue *vq)
 269 {
 270         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
 271         struct virtio_mmio_vq_info *info = vq->priv;
 272         unsigned long flags, size;
 273
 274         spin_lock_irqsave(&vm_dev->lock, flags);
 275         list_del(&info->node);
 276         spin_unlock_irqrestore(&vm_dev->lock, flags);
 277
 278         vring_del_virtqueue(vq);
 279
 280         /* Select and deactivate the queue */
 281         writel(info->queue_index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
 282         writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 283
 284         size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
 285         free_pages_exact(info->queue, size);
 286         kfree(info);
 287 }
 288
 289 static void vm_del_vqs(struct virtio_device *vdev)
 290 {
 291         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 292         struct virtqueue *vq, *n;
 293
 294         list_for_each_entry_safe(vq, n, &vdev->vqs, list)
 295                 vm_del_vq(vq);
 296
 297         free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
 298 }
 299
 300
 301
 302 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
 303                                   void (*callback)(struct virtqueue *vq),
 304                                   const char *name)
 305 {
 306         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 307         struct virtio_mmio_vq_info *info;
 308         struct virtqueue *vq;
 309         unsigned long flags, size;
 310         int err;
 311
 312         /* Select the queue we're interested in */
 313         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
 314
 315         /* Queue shouldn't already be set up. */
 316         if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) {
 317                 err = -ENOENT;
 318                 goto error_available;
 319         }
 320
 321         /* Allocate and fill out our active queue description */
 322         info = kmalloc(sizeof(*info), GFP_KERNEL);
 323         if (!info) {
 324                 err = -ENOMEM;
 325                 goto error_kmalloc;
 326         }
 327         info->queue_index = index;
 328
 329         /* Allocate pages for the queue - start with a queue as big as
 330          * possible (limited by maximum size allowed by device), drop down
 331          * to a minimal size, just big enough to fit descriptor table
 332          * and two rings (which makes it "alignment_size * 2")
 333          */
 334         info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
 335         while (1) {
 336                 size = PAGE_ALIGN(vring_size(info->num,
 337                                 VIRTIO_MMIO_VRING_ALIGN));
 338                 /* Already smallest possible allocation? */
 339                 if (size <= VIRTIO_MMIO_VRING_ALIGN * 2) {
 340                         err = -ENOMEM;
 341                         goto error_alloc_pages;
 342                 }
 343
 344                 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
 345                 if (info->queue)
 346                         break;
 347
 348                 info->num /= 2;
 349         }
 350
 351         /* Activate the queue */
 352         writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
 353         writel(VIRTIO_MMIO_VRING_ALIGN,
 354                         vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
 355         writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
 356                         vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 357
 358         /* Create the vring */
 359         vq = vring_new_virtqueue(info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
 360                                  true, info->queue, vm_notify, callback, name);
 361         if (!vq) {
 362                 err = -ENOMEM;
 363                 goto error_new_virtqueue;
 364         }
 365
 366         vq->priv = info;
 367         info->vq = vq;
 368
 369         spin_lock_irqsave(&vm_dev->lock, flags);
 370         list_add(&info->node, &vm_dev->virtqueues);
 371         spin_unlock_irqrestore(&vm_dev->lock, flags);
 372
 373         return vq;
 374
 375 error_new_virtqueue:
 376         writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 377         free_pages_exact(info->queue, size);
 378 error_alloc_pages:
 379         kfree(info);
 380 error_kmalloc:
 381 error_available:
 382         return ERR_PTR(err);
 383 }
 384
 385 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 386                        struct virtqueue *vqs[],
 387                        vq_callback_t *callbacks[],
 388                        const char *names[])
 389 {
 390         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 391         unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
 392         int i, err;
 393
 394         err = request_irq(irq, vm_interrupt, IRQF_SHARED,
 395                         dev_name(&vdev->dev), vm_dev);
 396         if (err)
 397                 return err;
 398
 399         for (i = 0; i < nvqs; ++i) {
 400                 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
 401                 if (IS_ERR(vqs[i])) {
 402                         vm_del_vqs(vdev);
 403                         return PTR_ERR(vqs[i]);
 404                 }
 405         }
 406
 407         return 0;
 408 }
 409
 410 static const char *vm_bus_name(struct virtio_device *vdev)
 411 {
 412         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 413
 414         return vm_dev->pdev->name;
 415 }
 416
 417 static struct virtio_config_ops virtio_mmio_config_ops = {
 418         .get            = vm_get,
 419         .set            = vm_set,
 420         .get_status     = vm_get_status,
 421         .set_status     = vm_set_status,
 422         .reset          = vm_reset,
 423         .find_vqs       = vm_find_vqs,
 424         .del_vqs        = vm_del_vqs,
 425         .get_features   = vm_get_features,
 426         .finalize_features = vm_finalize_features,
 427         .bus_name       = vm_bus_name,
 428 };
 429
 430
 431
 432 /* Platform device */
 433
 434 static int __devinit virtio_mmio_probe(struct platform_device *pdev)
 435 {
 436         struct virtio_mmio_device *vm_dev;
 437         struct resource *mem;
 438         unsigned long magic;
 439
 440         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 441         if (!mem)
 442                 return -EINVAL;
 443
 444         if (!devm_request_mem_region(&pdev->dev, mem->start,
 445                         resource_size(mem), pdev->name))
 446                 return -EBUSY;
 447
 448         vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
 449         if (!vm_dev)
 450                 return  -ENOMEM;
 451
 452         vm_dev->vdev.dev.parent = &pdev->dev;
 453         vm_dev->vdev.config = &virtio_mmio_config_ops;
 454         vm_dev->pdev = pdev;
 455         INIT_LIST_HEAD(&vm_dev->virtqueues);
 456         spin_lock_init(&vm_dev->lock);
 457
 458         vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
 459         if (vm_dev->base == NULL)
 460                 return -EFAULT;
 461
 462         /* Check magic value */
 463         magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
 464         if (memcmp(&magic, "virt", 4) != 0) {
 465                 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
 466                 return -ENODEV;
 467         }
 468
 469         /* Check device version */
 470         vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
 471         if (vm_dev->version != 1) {
 472                 dev_err(&pdev->dev, "Version %ld not supported!\n",
 473                                 vm_dev->version);
 474                 return -ENXIO;
 475         }
 476
 477         vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
 478         vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
 479
 480         writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
 481
 482         platform_set_drvdata(pdev, vm_dev);
 483
 484         return register_virtio_device(&vm_dev->vdev);
 485 }
 486
 487 static int __devexit virtio_mmio_remove(struct platform_device *pdev)
 488 {
 489         struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
 490
 491         unregister_virtio_device(&vm_dev->vdev);
 492
 493         return 0;
 494 }
 495
 496
 497
 498 /* Devices list parameter */
 499
 500 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
 501
 502 static struct device vm_cmdline_parent = {
 503         .init_name = "virtio-mmio-cmdline",
 504 };
 505
 506 static int vm_cmdline_parent_registered;
 507 static int vm_cmdline_id;
 508
 509 static int vm_cmdline_set(const char *device,
 510                 const struct kernel_param *kp)
 511 {
 512         int err;
 513         struct resource resources[2] = {};
 514         char *str;
 515         long long int base;
 516         int processed, consumed = 0;
 517         struct platform_device *pdev;
 518
 519         resources[0].flags = IORESOURCE_MEM;
 520         resources[1].flags = IORESOURCE_IRQ;
 521
 522         resources[0].end = memparse(device, &str) - 1;
 523
 524         processed = sscanf(str, "@%lli:%u%n:%d%n",
 525                         &base, &resources[1].start, &consumed,
 526                         &vm_cmdline_id, &consumed);
 527
 528         if (processed < 2 || processed > 3 || str[consumed])
 529                 return -EINVAL;
 530
 531         resources[0].start = base;
 532         resources[0].end += base;
 533         resources[1].end = resources[1].start;
 534
 535         if (!vm_cmdline_parent_registered) {
 536                 err = device_register(&vm_cmdline_parent);
 537                 if (err) {
 538                         pr_err("Failed to register parent device!\n");
 539                         return err;
 540                 }
 541                 vm_cmdline_parent_registered = 1;
 542         }
 543
 544         pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
 545                        vm_cmdline_id,
 546                        (unsigned long long)resources[0].start,
 547                        (unsigned long long)resources[0].end,
 548                        (int)resources[1].start);
 549
 550         pdev = platform_device_register_resndata(&vm_cmdline_parent,
 551                         "virtio-mmio", vm_cmdline_id++,
 552                         resources, ARRAY_SIZE(resources), NULL, 0);
 553         if (IS_ERR(pdev))
 554                 return PTR_ERR(pdev);
 555
 556         return 0;
 557 }
 558
 559 static int vm_cmdline_get_device(struct device *dev, void *data)
 560 {
 561         char *buffer = data;
 562         unsigned int len = strlen(buffer);
 563         struct platform_device *pdev = to_platform_device(dev);
 564
 565         snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
 566                         pdev->resource[0].end - pdev->resource[0].start + 1ULL,
 567                         (unsigned long long)pdev->resource[0].start,
 568                         (unsigned long long)pdev->resource[1].start,
 569                         pdev->id);
 570         return 0;
 571 }
 572
 573 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
 574 {
 575         buffer[0] = '\0';
 576         device_for_each_child(&vm_cmdline_parent, buffer,
 577                         vm_cmdline_get_device);
 578         return strlen(buffer) + 1;
 579 }
 580
 581 static struct kernel_param_ops vm_cmdline_param_ops = {
 582         .set = vm_cmdline_set,
 583         .get = vm_cmdline_get,
 584 };
 585
 586 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
 587
 588 static int vm_unregister_cmdline_device(struct device *dev,
 589                 void *data)
 590 {
 591         platform_device_unregister(to_platform_device(dev));
 592
 593         return 0;
 594 }
 595
 596 static void vm_unregister_cmdline_devices(void)
 597 {
 598         if (vm_cmdline_parent_registered) {
 599                 device_for_each_child(&vm_cmdline_parent, NULL,
 600                                 vm_unregister_cmdline_device);
 601                 device_unregister(&vm_cmdline_parent);
 602                 vm_cmdline_parent_registered = 0;
 603         }
 604 }
 605
 606 #else
 607
 608 static void vm_unregister_cmdline_devices(void)
 609 {
 610 }
 611
 612 #endif
 613
 614 /* Platform driver */
 615
 616 static struct of_device_id virtio_mmio_match[] = {
 617         { .compatible = "virtio,mmio", },
 618         {},
 619 };
 620 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
 621
 622 static struct platform_driver virtio_mmio_driver = {
 623         .probe          = virtio_mmio_probe,
 624         .remove         = __devexit_p(virtio_mmio_remove),
 625         .driver         = {
 626                 .name   = "virtio-mmio",
 627                 .owner  = THIS_MODULE,
 628                 .of_match_table = virtio_mmio_match,
 629         },
 630 };
 631
 632 static int __init virtio_mmio_init(void)
 633 {
 634         return platform_driver_register(&virtio_mmio_driver);
 635 }
 636
 637 static void __exit virtio_mmio_exit(void)
 638 {
 639         platform_driver_unregister(&virtio_mmio_driver);
 640         vm_unregister_cmdline_devices();
 641 }
 642
 643 module_init(virtio_mmio_init);
 644 module_exit(virtio_mmio_exit);
 645
 646 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
 647 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
 648 MODULE_LICENSE("GPL");