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 virtual address of the ring queue */
 135         void *queue;
 136
 137         /* the list node for the virtqueues list */
 138         struct list_head node;
 139 };
 140
 141
 142
 143 /* Configuration interface */
 144
 145 static u32 vm_get_features(struct virtio_device *vdev)
 146 {
 147         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 148
 149         /* TODO: Features > 32 bits */
 150         writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL);
 151
 152         return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
 153 }
 154
 155 static void vm_finalize_features(struct virtio_device *vdev)
 156 {
 157         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 158         int i;
 159
 160         /* Give virtio_ring a chance to accept features. */
 161         vring_transport_features(vdev);
 162
 163         for (i = 0; i < ARRAY_SIZE(vdev->features); i++) {
 164                 writel(i, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
 165                 writel(vdev->features[i],
 166                                 vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
 167         }
 168 }
 169
 170 static void vm_get(struct virtio_device *vdev, unsigned offset,
 171                    void *buf, unsigned len)
 172 {
 173         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 174         u8 *ptr = buf;
 175         int i;
 176
 177         for (i = 0; i < len; i++)
 178                 ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
 179 }
 180
 181 static void vm_set(struct virtio_device *vdev, unsigned offset,
 182                    const void *buf, unsigned len)
 183 {
 184         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 185         const u8 *ptr = buf;
 186         int i;
 187
 188         for (i = 0; i < len; i++)
 189                 writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
 190 }
 191
 192 static u8 vm_get_status(struct virtio_device *vdev)
 193 {
 194         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 195
 196         return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
 197 }
 198
 199 static void vm_set_status(struct virtio_device *vdev, u8 status)
 200 {
 201         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 202
 203         /* We should never be setting status to 0. */
 204         BUG_ON(status == 0);
 205
 206         writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
 207 }
 208
 209 static void vm_reset(struct virtio_device *vdev)
 210 {
 211         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 212
 213         /* 0 status means a reset. */
 214         writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
 215 }
 216
 217
 218
 219 /* Transport interface */
 220
 221 /* the notify function used when creating a virt queue */
 222 static void vm_notify(struct virtqueue *vq)
 223 {
 224         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
 225
 226         /* We write the queue's selector into the notification register to
 227          * signal the other end */
 228         writel(virtqueue_get_queue_index(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
 229 }
 230
 231 /* Notify all virtqueues on an interrupt. */
 232 static irqreturn_t vm_interrupt(int irq, void *opaque)
 233 {
 234         struct virtio_mmio_device *vm_dev = opaque;
 235         struct virtio_mmio_vq_info *info;
 236         struct virtio_driver *vdrv = container_of(vm_dev->vdev.dev.driver,
 237                         struct virtio_driver, driver);
 238         unsigned long status;
 239         unsigned long flags;
 240         irqreturn_t ret = IRQ_NONE;
 241
 242         /* Read and acknowledge interrupts */
 243         status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
 244         writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
 245
 246         if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)
 247                         && vdrv && vdrv->config_changed) {
 248                 vdrv->config_changed(&vm_dev->vdev);
 249                 ret = IRQ_HANDLED;
 250         }
 251
 252         if (likely(status & VIRTIO_MMIO_INT_VRING)) {
 253                 spin_lock_irqsave(&vm_dev->lock, flags);
 254                 list_for_each_entry(info, &vm_dev->virtqueues, node)
 255                         ret |= vring_interrupt(irq, info->vq);
 256                 spin_unlock_irqrestore(&vm_dev->lock, flags);
 257         }
 258
 259         return ret;
 260 }
 261
 262
 263
 264 static void vm_del_vq(struct virtqueue *vq)
 265 {
 266         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
 267         struct virtio_mmio_vq_info *info = vq->priv;
 268         unsigned long flags, size;
 269         unsigned int index = virtqueue_get_queue_index(vq);
 270
 271         spin_lock_irqsave(&vm_dev->lock, flags);
 272         list_del(&info->node);
 273         spin_unlock_irqrestore(&vm_dev->lock, flags);
 274
 275         vring_del_virtqueue(vq);
 276
 277         /* Select and deactivate the queue */
 278         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
 279         writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 280
 281         size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
 282         free_pages_exact(info->queue, size);
 283         kfree(info);
 284 }
 285
 286 static void vm_del_vqs(struct virtio_device *vdev)
 287 {
 288         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 289         struct virtqueue *vq, *n;
 290
 291         list_for_each_entry_safe(vq, n, &vdev->vqs, list)
 292                 vm_del_vq(vq);
 293
 294         free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
 295 }
 296
 297
 298
 299 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
 300                                   void (*callback)(struct virtqueue *vq),
 301                                   const char *name)
 302 {
 303         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 304         struct virtio_mmio_vq_info *info;
 305         struct virtqueue *vq;
 306         unsigned long flags, size;
 307         int err;
 308
 309         if (!name)
 310                 return NULL;
 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
 328         /* Allocate pages for the queue - start with a queue as big as
 329          * possible (limited by maximum size allowed by device), drop down
 330          * to a minimal size, just big enough to fit descriptor table
 331          * and two rings (which makes it "alignment_size * 2")
 332          */
 333         info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
 334
 335         /* If the device reports a 0 entry queue, we won't be able to
 336          * use it to perform I/O, and vring_new_virtqueue() can't create
 337          * empty queues anyway, so don't bother to set up the device.
 338          */
 339         if (info->num == 0) {
 340                 err = -ENOENT;
 341                 goto error_alloc_pages;
 342         }
 343
 344         while (1) {
 345                 size = PAGE_ALIGN(vring_size(info->num,
 346                                 VIRTIO_MMIO_VRING_ALIGN));
 347                 /* Did the last iter shrink the queue below minimum size? */
 348                 if (size < VIRTIO_MMIO_VRING_ALIGN * 2) {
 349                         err = -ENOMEM;
 350                         goto error_alloc_pages;
 351                 }
 352
 353                 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
 354                 if (info->queue)
 355                         break;
 356
 357                 info->num /= 2;
 358         }
 359
 360         /* Activate the queue */
 361         writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
 362         writel(VIRTIO_MMIO_VRING_ALIGN,
 363                         vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
 364         writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
 365                         vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 366
 367         /* Create the vring */
 368         vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
 369                                  true, info->queue, vm_notify, callback, name);
 370         if (!vq) {
 371                 err = -ENOMEM;
 372                 goto error_new_virtqueue;
 373         }
 374
 375         vq->priv = info;
 376         info->vq = vq;
 377
 378         spin_lock_irqsave(&vm_dev->lock, flags);
 379         list_add(&info->node, &vm_dev->virtqueues);
 380         spin_unlock_irqrestore(&vm_dev->lock, flags);
 381
 382         return vq;
 383
 384 error_new_virtqueue:
 385         writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 386         free_pages_exact(info->queue, size);
 387 error_alloc_pages:
 388         kfree(info);
 389 error_kmalloc:
 390 error_available:
 391         return ERR_PTR(err);
 392 }
 393
 394 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 395                        struct virtqueue *vqs[],
 396                        vq_callback_t *callbacks[],
 397                        const char *names[])
 398 {
 399         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 400         unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
 401         int i, err;
 402
 403         err = request_irq(irq, vm_interrupt, IRQF_SHARED,
 404                         dev_name(&vdev->dev), vm_dev);
 405         if (err)
 406                 return err;
 407
 408         for (i = 0; i < nvqs; ++i) {
 409                 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
 410                 if (IS_ERR(vqs[i])) {
 411                         vm_del_vqs(vdev);
 412                         return PTR_ERR(vqs[i]);
 413                 }
 414         }
 415
 416         return 0;
 417 }
 418
 419 static const char *vm_bus_name(struct virtio_device *vdev)
 420 {
 421         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 422
 423         return vm_dev->pdev->name;
 424 }
 425
 426 static struct virtio_config_ops virtio_mmio_config_ops = {
 427         .get            = vm_get,
 428         .set            = vm_set,
 429         .get_status     = vm_get_status,
 430         .set_status     = vm_set_status,
 431         .reset          = vm_reset,
 432         .find_vqs       = vm_find_vqs,
 433         .del_vqs        = vm_del_vqs,
 434         .get_features   = vm_get_features,
 435         .finalize_features = vm_finalize_features,
 436         .bus_name       = vm_bus_name,
 437 };
 438
 439
 440
 441 /* Platform device */
 442
 443 static int __devinit virtio_mmio_probe(struct platform_device *pdev)
 444 {
 445         struct virtio_mmio_device *vm_dev;
 446         struct resource *mem;
 447         unsigned long magic;
 448
 449         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 450         if (!mem)
 451                 return -EINVAL;
 452
 453         if (!devm_request_mem_region(&pdev->dev, mem->start,
 454                         resource_size(mem), pdev->name))
 455                 return -EBUSY;
 456
 457         vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
 458         if (!vm_dev)
 459                 return  -ENOMEM;
 460
 461         vm_dev->vdev.dev.parent = &pdev->dev;
 462         vm_dev->vdev.config = &virtio_mmio_config_ops;
 463         vm_dev->pdev = pdev;
 464         INIT_LIST_HEAD(&vm_dev->virtqueues);
 465         spin_lock_init(&vm_dev->lock);
 466
 467         vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
 468         if (vm_dev->base == NULL)
 469                 return -EFAULT;
 470
 471         /* Check magic value */
 472         magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
 473         if (memcmp(&magic, "virt", 4) != 0) {
 474                 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
 475                 return -ENODEV;
 476         }
 477
 478         /* Check device version */
 479         vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
 480         if (vm_dev->version != 1) {
 481                 dev_err(&pdev->dev, "Version %ld not supported!\n",
 482                                 vm_dev->version);
 483                 return -ENXIO;
 484         }
 485
 486         vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
 487         vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
 488
 489         writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
 490
 491         platform_set_drvdata(pdev, vm_dev);
 492
 493         return register_virtio_device(&vm_dev->vdev);
 494 }
 495
 496 static int __devexit virtio_mmio_remove(struct platform_device *pdev)
 497 {
 498         struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
 499
 500         unregister_virtio_device(&vm_dev->vdev);
 501
 502         return 0;
 503 }
 504
 505
 506
 507 /* Devices list parameter */
 508
 509 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
 510
 511 static struct device vm_cmdline_parent = {
 512         .init_name = "virtio-mmio-cmdline",
 513 };
 514
 515 static int vm_cmdline_parent_registered;
 516 static int vm_cmdline_id;
 517
 518 static int vm_cmdline_set(const char *device,
 519                 const struct kernel_param *kp)
 520 {
 521         int err;
 522         struct resource resources[2] = {};
 523         char *str;
 524         long long int base;
 525         int processed, consumed = 0;
 526         struct platform_device *pdev;
 527
 528         resources[0].flags = IORESOURCE_MEM;
 529         resources[1].flags = IORESOURCE_IRQ;
 530
 531         resources[0].end = memparse(device, &str) - 1;
 532
 533         processed = sscanf(str, "@%lli:%u%n:%d%n",
 534                         &base, &resources[1].start, &consumed,
 535                         &vm_cmdline_id, &consumed);
 536
 537         if (processed < 2 || processed > 3 || str[consumed])
 538                 return -EINVAL;
 539
 540         resources[0].start = base;
 541         resources[0].end += base;
 542         resources[1].end = resources[1].start;
 543
 544         if (!vm_cmdline_parent_registered) {
 545                 err = device_register(&vm_cmdline_parent);
 546                 if (err) {
 547                         pr_err("Failed to register parent device!\n");
 548                         return err;
 549                 }
 550                 vm_cmdline_parent_registered = 1;
 551         }
 552
 553         pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
 554                        vm_cmdline_id,
 555                        (unsigned long long)resources[0].start,
 556                        (unsigned long long)resources[0].end,
 557                        (int)resources[1].start);
 558
 559         pdev = platform_device_register_resndata(&vm_cmdline_parent,
 560                         "virtio-mmio", vm_cmdline_id++,
 561                         resources, ARRAY_SIZE(resources), NULL, 0);
 562         if (IS_ERR(pdev))
 563                 return PTR_ERR(pdev);
 564
 565         return 0;
 566 }
 567
 568 static int vm_cmdline_get_device(struct device *dev, void *data)
 569 {
 570         char *buffer = data;
 571         unsigned int len = strlen(buffer);
 572         struct platform_device *pdev = to_platform_device(dev);
 573
 574         snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
 575                         pdev->resource[0].end - pdev->resource[0].start + 1ULL,
 576                         (unsigned long long)pdev->resource[0].start,
 577                         (unsigned long long)pdev->resource[1].start,
 578                         pdev->id);
 579         return 0;
 580 }
 581
 582 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
 583 {
 584         buffer[0] = '\0';
 585         device_for_each_child(&vm_cmdline_parent, buffer,
 586                         vm_cmdline_get_device);
 587         return strlen(buffer) + 1;
 588 }
 589
 590 static struct kernel_param_ops vm_cmdline_param_ops = {
 591         .set = vm_cmdline_set,
 592         .get = vm_cmdline_get,
 593 };
 594
 595 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
 596
 597 static int vm_unregister_cmdline_device(struct device *dev,
 598                 void *data)
 599 {
 600         platform_device_unregister(to_platform_device(dev));
 601
 602         return 0;
 603 }
 604
 605 static void vm_unregister_cmdline_devices(void)
 606 {
 607         if (vm_cmdline_parent_registered) {
 608                 device_for_each_child(&vm_cmdline_parent, NULL,
 609                                 vm_unregister_cmdline_device);
 610                 device_unregister(&vm_cmdline_parent);
 611                 vm_cmdline_parent_registered = 0;
 612         }
 613 }
 614
 615 #else
 616
 617 static void vm_unregister_cmdline_devices(void)
 618 {
 619 }
 620
 621 #endif
 622
 623 /* Platform driver */
 624
 625 static struct of_device_id virtio_mmio_match[] = {
 626         { .compatible = "virtio,mmio", },
 627         {},
 628 };
 629 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
 630
 631 static struct platform_driver virtio_mmio_driver = {
 632         .probe          = virtio_mmio_probe,
 633         .remove         = __devexit_p(virtio_mmio_remove),
 634         .driver         = {
 635                 .name   = "virtio-mmio",
 636                 .owner  = THIS_MODULE,
 637                 .of_match_table = virtio_mmio_match,
 638         },
 639 };
 640
 641 static int __init virtio_mmio_init(void)
 642 {
 643         return platform_driver_register(&virtio_mmio_driver);
 644 }
 645
 646 static void __exit virtio_mmio_exit(void)
 647 {
 648         platform_driver_unregister(&virtio_mmio_driver);
 649         vm_unregister_cmdline_devices();
 650 }
 651
 652 module_init(virtio_mmio_init);
 653 module_exit(virtio_mmio_exit);
 654
 655 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
 656 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
 657 MODULE_LICENSE("GPL");