xref: /openbmc/linux/drivers/virtio/virtio_mmio.c (revision e23feb16)
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 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(vq->index, 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 = vq->index;
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 const 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 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 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, size;
525 	unsigned int irq;
526 	int processed, consumed = 0;
527 	struct platform_device *pdev;
528 
529 	/* Consume "size" part of the command line parameter */
530 	size = memparse(device, &str);
531 
532 	/* Get "@<base>:<irq>[:<id>]" chunks */
533 	processed = sscanf(str, "@%lli:%u%n:%d%n",
534 			&base, &irq, &consumed,
535 			&vm_cmdline_id, &consumed);
536 
537 	/*
538 	 * sscanf() must processes at least 2 chunks; also there
539 	 * must be no extra characters after the last chunk, so
540 	 * str[consumed] must be '\0'
541 	 */
542 	if (processed < 2 || str[consumed])
543 		return -EINVAL;
544 
545 	resources[0].flags = IORESOURCE_MEM;
546 	resources[0].start = base;
547 	resources[0].end = base + size - 1;
548 
549 	resources[1].flags = IORESOURCE_IRQ;
550 	resources[1].start = resources[1].end = irq;
551 
552 	if (!vm_cmdline_parent_registered) {
553 		err = device_register(&vm_cmdline_parent);
554 		if (err) {
555 			pr_err("Failed to register parent device!\n");
556 			return err;
557 		}
558 		vm_cmdline_parent_registered = 1;
559 	}
560 
561 	pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
562 		       vm_cmdline_id,
563 		       (unsigned long long)resources[0].start,
564 		       (unsigned long long)resources[0].end,
565 		       (int)resources[1].start);
566 
567 	pdev = platform_device_register_resndata(&vm_cmdline_parent,
568 			"virtio-mmio", vm_cmdline_id++,
569 			resources, ARRAY_SIZE(resources), NULL, 0);
570 	if (IS_ERR(pdev))
571 		return PTR_ERR(pdev);
572 
573 	return 0;
574 }
575 
576 static int vm_cmdline_get_device(struct device *dev, void *data)
577 {
578 	char *buffer = data;
579 	unsigned int len = strlen(buffer);
580 	struct platform_device *pdev = to_platform_device(dev);
581 
582 	snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
583 			pdev->resource[0].end - pdev->resource[0].start + 1ULL,
584 			(unsigned long long)pdev->resource[0].start,
585 			(unsigned long long)pdev->resource[1].start,
586 			pdev->id);
587 	return 0;
588 }
589 
590 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
591 {
592 	buffer[0] = '\0';
593 	device_for_each_child(&vm_cmdline_parent, buffer,
594 			vm_cmdline_get_device);
595 	return strlen(buffer) + 1;
596 }
597 
598 static struct kernel_param_ops vm_cmdline_param_ops = {
599 	.set = vm_cmdline_set,
600 	.get = vm_cmdline_get,
601 };
602 
603 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
604 
605 static int vm_unregister_cmdline_device(struct device *dev,
606 		void *data)
607 {
608 	platform_device_unregister(to_platform_device(dev));
609 
610 	return 0;
611 }
612 
613 static void vm_unregister_cmdline_devices(void)
614 {
615 	if (vm_cmdline_parent_registered) {
616 		device_for_each_child(&vm_cmdline_parent, NULL,
617 				vm_unregister_cmdline_device);
618 		device_unregister(&vm_cmdline_parent);
619 		vm_cmdline_parent_registered = 0;
620 	}
621 }
622 
623 #else
624 
625 static void vm_unregister_cmdline_devices(void)
626 {
627 }
628 
629 #endif
630 
631 /* Platform driver */
632 
633 static struct of_device_id virtio_mmio_match[] = {
634 	{ .compatible = "virtio,mmio", },
635 	{},
636 };
637 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
638 
639 static struct platform_driver virtio_mmio_driver = {
640 	.probe		= virtio_mmio_probe,
641 	.remove		= virtio_mmio_remove,
642 	.driver		= {
643 		.name	= "virtio-mmio",
644 		.owner	= THIS_MODULE,
645 		.of_match_table	= virtio_mmio_match,
646 	},
647 };
648 
649 static int __init virtio_mmio_init(void)
650 {
651 	return platform_driver_register(&virtio_mmio_driver);
652 }
653 
654 static void __exit virtio_mmio_exit(void)
655 {
656 	platform_driver_unregister(&virtio_mmio_driver);
657 	vm_unregister_cmdline_devices();
658 }
659 
660 module_init(virtio_mmio_init);
661 module_exit(virtio_mmio_exit);
662 
663 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
664 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
665 MODULE_LICENSE("GPL");
666