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  * 0x064  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 u64 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 int vm_finalize_features(struct virtio_device *vdev)
 156 {
 157         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 158
 159         /* Give virtio_ring a chance to accept features. */
 160         vring_transport_features(vdev);
 161
 162         /* Make sure we don't have any features > 32 bits! */
 163         BUG_ON((u32)vdev->features != vdev->features);
 164
 165         writel(0, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
 166         writel(vdev->features, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
 167
 168         return 0;
 169 }
 170
 171 static void vm_get(struct virtio_device *vdev, unsigned offset,
 172                    void *buf, unsigned len)
 173 {
 174         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 175         u8 *ptr = buf;
 176         int i;
 177
 178         for (i = 0; i < len; i++)
 179                 ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
 180 }
 181
 182 static void vm_set(struct virtio_device *vdev, unsigned offset,
 183                    const void *buf, unsigned len)
 184 {
 185         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 186         const u8 *ptr = buf;
 187         int i;
 188
 189         for (i = 0; i < len; i++)
 190                 writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
 191 }
 192
 193 static u8 vm_get_status(struct virtio_device *vdev)
 194 {
 195         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 196
 197         return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
 198 }
 199
 200 static void vm_set_status(struct virtio_device *vdev, u8 status)
 201 {
 202         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 203
 204         /* We should never be setting status to 0. */
 205         BUG_ON(status == 0);
 206
 207         writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
 208 }
 209
 210 static void vm_reset(struct virtio_device *vdev)
 211 {
 212         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 213
 214         /* 0 status means a reset. */
 215         writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
 216 }
 217
 218
 219
 220 /* Transport interface */
 221
 222 /* the notify function used when creating a virt queue */
 223 static bool vm_notify(struct virtqueue *vq)
 224 {
 225         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
 226
 227         /* We write the queue's selector into the notification register to
 228          * signal the other end */
 229         writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
 230         return true;
 231 }
 232
 233 /* Notify all virtqueues on an interrupt. */
 234 static irqreturn_t vm_interrupt(int irq, void *opaque)
 235 {
 236         struct virtio_mmio_device *vm_dev = opaque;
 237         struct virtio_mmio_vq_info *info;
 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                 virtio_config_changed(&vm_dev->vdev);
 248                 ret = IRQ_HANDLED;
 249         }
 250
 251         if (likely(status & VIRTIO_MMIO_INT_VRING)) {
 252                 spin_lock_irqsave(&vm_dev->lock, flags);
 253                 list_for_each_entry(info, &vm_dev->virtqueues, node)
 254                         ret |= vring_interrupt(irq, info->vq);
 255                 spin_unlock_irqrestore(&vm_dev->lock, flags);
 256         }
 257
 258         return ret;
 259 }
 260
 261
 262
 263 static void vm_del_vq(struct virtqueue *vq)
 264 {
 265         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
 266         struct virtio_mmio_vq_info *info = vq->priv;
 267         unsigned long flags, size;
 268         unsigned int index = vq->index;
 269
 270         spin_lock_irqsave(&vm_dev->lock, flags);
 271         list_del(&info->node);
 272         spin_unlock_irqrestore(&vm_dev->lock, flags);
 273
 274         vring_del_virtqueue(vq);
 275
 276         /* Select and deactivate the queue */
 277         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
 278         writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 279
 280         size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
 281         free_pages_exact(info->queue, size);
 282         kfree(info);
 283 }
 284
 285 static void vm_del_vqs(struct virtio_device *vdev)
 286 {
 287         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 288         struct virtqueue *vq, *n;
 289
 290         list_for_each_entry_safe(vq, n, &vdev->vqs, list)
 291                 vm_del_vq(vq);
 292
 293         free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
 294 }
 295
 296
 297
 298 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
 299                                   void (*callback)(struct virtqueue *vq),
 300                                   const char *name)
 301 {
 302         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 303         struct virtio_mmio_vq_info *info;
 304         struct virtqueue *vq;
 305         unsigned long flags, size;
 306         int err;
 307
 308         if (!name)
 309                 return NULL;
 310
 311         /* Select the queue we're interested in */
 312         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
 313
 314         /* Queue shouldn't already be set up. */
 315         if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) {
 316                 err = -ENOENT;
 317                 goto error_available;
 318         }
 319
 320         /* Allocate and fill out our active queue description */
 321         info = kmalloc(sizeof(*info), GFP_KERNEL);
 322         if (!info) {
 323                 err = -ENOMEM;
 324                 goto error_kmalloc;
 325         }
 326
 327         /* Allocate pages for the queue - start with a queue as big as
 328          * possible (limited by maximum size allowed by device), drop down
 329          * to a minimal size, just big enough to fit descriptor table
 330          * and two rings (which makes it "alignment_size * 2")
 331          */
 332         info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
 333
 334         /* If the device reports a 0 entry queue, we won't be able to
 335          * use it to perform I/O, and vring_new_virtqueue() can't create
 336          * empty queues anyway, so don't bother to set up the device.
 337          */
 338         if (info->num == 0) {
 339                 err = -ENOENT;
 340                 goto error_alloc_pages;
 341         }
 342
 343         while (1) {
 344                 size = PAGE_ALIGN(vring_size(info->num,
 345                                 VIRTIO_MMIO_VRING_ALIGN));
 346                 /* Did the last iter shrink the queue below minimum size? */
 347                 if (size < VIRTIO_MMIO_VRING_ALIGN * 2) {
 348                         err = -ENOMEM;
 349                         goto error_alloc_pages;
 350                 }
 351
 352                 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
 353                 if (info->queue)
 354                         break;
 355
 356                 info->num /= 2;
 357         }
 358
 359         /* Activate the queue */
 360         writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
 361         writel(VIRTIO_MMIO_VRING_ALIGN,
 362                         vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
 363         writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
 364                         vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 365
 366         /* Create the vring */
 367         vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
 368                                  true, info->queue, vm_notify, callback, name);
 369         if (!vq) {
 370                 err = -ENOMEM;
 371                 goto error_new_virtqueue;
 372         }
 373
 374         vq->priv = info;
 375         info->vq = vq;
 376
 377         spin_lock_irqsave(&vm_dev->lock, flags);
 378         list_add(&info->node, &vm_dev->virtqueues);
 379         spin_unlock_irqrestore(&vm_dev->lock, flags);
 380
 381         return vq;
 382
 383 error_new_virtqueue:
 384         writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 385         free_pages_exact(info->queue, size);
 386 error_alloc_pages:
 387         kfree(info);
 388 error_kmalloc:
 389 error_available:
 390         return ERR_PTR(err);
 391 }
 392
 393 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 394                        struct virtqueue *vqs[],
 395                        vq_callback_t *callbacks[],
 396                        const char *names[])
 397 {
 398         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 399         unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
 400         int i, err;
 401
 402         err = request_irq(irq, vm_interrupt, IRQF_SHARED,
 403                         dev_name(&vdev->dev), vm_dev);
 404         if (err)
 405                 return err;
 406
 407         for (i = 0; i < nvqs; ++i) {
 408                 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
 409                 if (IS_ERR(vqs[i])) {
 410                         vm_del_vqs(vdev);
 411                         return PTR_ERR(vqs[i]);
 412                 }
 413         }
 414
 415         return 0;
 416 }
 417
 418 static const char *vm_bus_name(struct virtio_device *vdev)
 419 {
 420         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 421
 422         return vm_dev->pdev->name;
 423 }
 424
 425 static const struct virtio_config_ops virtio_mmio_config_ops = {
 426         .get            = vm_get,
 427         .set            = vm_set,
 428         .get_status     = vm_get_status,
 429         .set_status     = vm_set_status,
 430         .reset          = vm_reset,
 431         .find_vqs       = vm_find_vqs,
 432         .del_vqs        = vm_del_vqs,
 433         .get_features   = vm_get_features,
 434         .finalize_features = vm_finalize_features,
 435         .bus_name       = vm_bus_name,
 436 };
 437
 438
 439
 440 /* Platform device */
 441
 442 static int virtio_mmio_probe(struct platform_device *pdev)
 443 {
 444         struct virtio_mmio_device *vm_dev;
 445         struct resource *mem;
 446         unsigned long magic;
 447
 448         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 449         if (!mem)
 450                 return -EINVAL;
 451
 452         if (!devm_request_mem_region(&pdev->dev, mem->start,
 453                         resource_size(mem), pdev->name))
 454                 return -EBUSY;
 455
 456         vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
 457         if (!vm_dev)
 458                 return  -ENOMEM;
 459
 460         vm_dev->vdev.dev.parent = &pdev->dev;
 461         vm_dev->vdev.config = &virtio_mmio_config_ops;
 462         vm_dev->pdev = pdev;
 463         INIT_LIST_HEAD(&vm_dev->virtqueues);
 464         spin_lock_init(&vm_dev->lock);
 465
 466         vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
 467         if (vm_dev->base == NULL)
 468                 return -EFAULT;
 469
 470         /* Check magic value */
 471         magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
 472         if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
 473                 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
 474                 return -ENODEV;
 475         }
 476
 477         /* Check device version */
 478         vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
 479         if (vm_dev->version != 1) {
 480                 dev_err(&pdev->dev, "Version %ld not supported!\n",
 481                                 vm_dev->version);
 482                 return -ENXIO;
 483         }
 484
 485         vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
 486         vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
 487
 488         writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
 489
 490         platform_set_drvdata(pdev, vm_dev);
 491
 492         return register_virtio_device(&vm_dev->vdev);
 493 }
 494
 495 static int virtio_mmio_remove(struct platform_device *pdev)
 496 {
 497         struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
 498
 499         unregister_virtio_device(&vm_dev->vdev);
 500
 501         return 0;
 502 }
 503
 504
 505
 506 /* Devices list parameter */
 507
 508 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
 509
 510 static struct device vm_cmdline_parent = {
 511         .init_name = "virtio-mmio-cmdline",
 512 };
 513
 514 static int vm_cmdline_parent_registered;
 515 static int vm_cmdline_id;
 516
 517 static int vm_cmdline_set(const char *device,
 518                 const struct kernel_param *kp)
 519 {
 520         int err;
 521         struct resource resources[2] = {};
 522         char *str;
 523         long long int base, size;
 524         unsigned int irq;
 525         int processed, consumed = 0;
 526         struct platform_device *pdev;
 527
 528         /* Consume "size" part of the command line parameter */
 529         size = memparse(device, &str);
 530
 531         /* Get "@<base>:<irq>[:<id>]" chunks */
 532         processed = sscanf(str, "@%lli:%u%n:%d%n",
 533                         &base, &irq, &consumed,
 534                         &vm_cmdline_id, &consumed);
 535
 536         /*
 537          * sscanf() must processes at least 2 chunks; also there
 538          * must be no extra characters after the last chunk, so
 539          * str[consumed] must be '\0'
 540          */
 541         if (processed < 2 || str[consumed])
 542                 return -EINVAL;
 543
 544         resources[0].flags = IORESOURCE_MEM;
 545         resources[0].start = base;
 546         resources[0].end = base + size - 1;
 547
 548         resources[1].flags = IORESOURCE_IRQ;
 549         resources[1].start = resources[1].end = irq;
 550
 551         if (!vm_cmdline_parent_registered) {
 552                 err = device_register(&vm_cmdline_parent);
 553                 if (err) {
 554                         pr_err("Failed to register parent device!\n");
 555                         return err;
 556                 }
 557                 vm_cmdline_parent_registered = 1;
 558         }
 559
 560         pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
 561                        vm_cmdline_id,
 562                        (unsigned long long)resources[0].start,
 563                        (unsigned long long)resources[0].end,
 564                        (int)resources[1].start);
 565
 566         pdev = platform_device_register_resndata(&vm_cmdline_parent,
 567                         "virtio-mmio", vm_cmdline_id++,
 568                         resources, ARRAY_SIZE(resources), NULL, 0);
 569         if (IS_ERR(pdev))
 570                 return PTR_ERR(pdev);
 571
 572         return 0;
 573 }
 574
 575 static int vm_cmdline_get_device(struct device *dev, void *data)
 576 {
 577         char *buffer = data;
 578         unsigned int len = strlen(buffer);
 579         struct platform_device *pdev = to_platform_device(dev);
 580
 581         snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
 582                         pdev->resource[0].end - pdev->resource[0].start + 1ULL,
 583                         (unsigned long long)pdev->resource[0].start,
 584                         (unsigned long long)pdev->resource[1].start,
 585                         pdev->id);
 586         return 0;
 587 }
 588
 589 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
 590 {
 591         buffer[0] = '\0';
 592         device_for_each_child(&vm_cmdline_parent, buffer,
 593                         vm_cmdline_get_device);
 594         return strlen(buffer) + 1;
 595 }
 596
 597 static struct kernel_param_ops vm_cmdline_param_ops = {
 598         .set = vm_cmdline_set,
 599         .get = vm_cmdline_get,
 600 };
 601
 602 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
 603
 604 static int vm_unregister_cmdline_device(struct device *dev,
 605                 void *data)
 606 {
 607         platform_device_unregister(to_platform_device(dev));
 608
 609         return 0;
 610 }
 611
 612 static void vm_unregister_cmdline_devices(void)
 613 {
 614         if (vm_cmdline_parent_registered) {
 615                 device_for_each_child(&vm_cmdline_parent, NULL,
 616                                 vm_unregister_cmdline_device);
 617                 device_unregister(&vm_cmdline_parent);
 618                 vm_cmdline_parent_registered = 0;
 619         }
 620 }
 621
 622 #else
 623
 624 static void vm_unregister_cmdline_devices(void)
 625 {
 626 }
 627
 628 #endif
 629
 630 /* Platform driver */
 631
 632 static struct of_device_id virtio_mmio_match[] = {
 633         { .compatible = "virtio,mmio", },
 634         {},
 635 };
 636 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
 637
 638 static struct platform_driver virtio_mmio_driver = {
 639         .probe          = virtio_mmio_probe,
 640         .remove         = virtio_mmio_remove,
 641         .driver         = {
 642                 .name   = "virtio-mmio",
 643                 .owner  = THIS_MODULE,
 644                 .of_match_table = virtio_mmio_match,
 645         },
 646 };
 647
 648 static int __init virtio_mmio_init(void)
 649 {
 650         return platform_driver_register(&virtio_mmio_driver);
 651 }
 652
 653 static void __exit virtio_mmio_exit(void)
 654 {
 655         platform_driver_unregister(&virtio_mmio_driver);
 656         vm_unregister_cmdline_devices();
 657 }
 658
 659 module_init(virtio_mmio_init);
 660 module_exit(virtio_mmio_exit);
 661
 662 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
 663 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
 664 MODULE_LICENSE("GPL");