1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Virtio memory mapped device driver
5 * Copyright 2011-2014, ARM Ltd.
7 * This module allows virtio devices to be used over a virtual, memory mapped
10 * The guest device(s) may be instantiated in one of three equivalent ways:
12 * 1. Static platform device in board's code, eg.:
14 * static struct platform_device v2m_virtio_device = {
15 * .name = "virtio-mmio",
18 * .resource = (struct resource []) {
20 * .start = 0x1001e000,
22 * .flags = IORESOURCE_MEM,
26 * .flags = IORESOURCE_IRQ,
31 * 2. Device Tree node, eg.:
33 * virtio_block@1e000 {
34 * compatible = "virtio,mmio";
35 * reg = <0x1e000 0x100>;
39 * 3. Kernel module (or command line) parameter. Can be used more than once -
40 * one device will be created for each one. Syntax:
42 * [virtio_mmio.]device=<size>@<baseaddr>:<irq>[:<id>]
44 * <size> := size (can use standard suffixes like K, M or G)
45 * <baseaddr> := physical base address
46 * <irq> := interrupt number (as passed to request_irq())
47 * <id> := (optional) platform device id
49 * virtio_mmio.device=0x100@0x100b0000:48 \
50 * virtio_mmio.device=1K@0x1001e000:74
52 * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
55 #define pr_fmt(fmt) "virtio-mmio: " fmt
57 #include <linux/acpi.h>
58 #include <linux/dma-mapping.h>
59 #include <linux/highmem.h>
60 #include <linux/interrupt.h>
62 #include <linux/list.h>
63 #include <linux/module.h>
64 #include <linux/platform_device.h>
65 #include <linux/slab.h>
66 #include <linux/spinlock.h>
67 #include <linux/virtio.h>
68 #include <linux/virtio_config.h>
69 #include <uapi/linux/virtio_mmio.h>
70 #include <linux/virtio_ring.h>
74 /* The alignment to use between consumer and producer parts of vring.
75 * Currently hardcoded to the page size. */
76 #define VIRTIO_MMIO_VRING_ALIGN PAGE_SIZE
80 #define to_virtio_mmio_device(_plat_dev) \
81 container_of(_plat_dev, struct virtio_mmio_device, vdev)
83 struct virtio_mmio_device
{
84 struct virtio_device vdev
;
85 struct platform_device
*pdev
;
88 unsigned long version
;
90 /* a list of queues so we can dispatch IRQs */
92 struct list_head virtqueues
;
95 struct virtio_mmio_vq_info
{
96 /* the actual virtqueue */
99 /* the list node for the virtqueues list */
100 struct list_head node
;
105 /* Configuration interface */
107 static u64
vm_get_features(struct virtio_device
*vdev
)
109 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
112 writel(1, vm_dev
->base
+ VIRTIO_MMIO_DEVICE_FEATURES_SEL
);
113 features
= readl(vm_dev
->base
+ VIRTIO_MMIO_DEVICE_FEATURES
);
116 writel(0, vm_dev
->base
+ VIRTIO_MMIO_DEVICE_FEATURES_SEL
);
117 features
|= readl(vm_dev
->base
+ VIRTIO_MMIO_DEVICE_FEATURES
);
122 static int vm_finalize_features(struct virtio_device
*vdev
)
124 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
126 /* Give virtio_ring a chance to accept features. */
127 vring_transport_features(vdev
);
129 /* Make sure there is are no mixed devices */
130 if (vm_dev
->version
== 2 &&
131 !__virtio_test_bit(vdev
, VIRTIO_F_VERSION_1
)) {
132 dev_err(&vdev
->dev
, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n");
136 writel(1, vm_dev
->base
+ VIRTIO_MMIO_DRIVER_FEATURES_SEL
);
137 writel((u32
)(vdev
->features
>> 32),
138 vm_dev
->base
+ VIRTIO_MMIO_DRIVER_FEATURES
);
140 writel(0, vm_dev
->base
+ VIRTIO_MMIO_DRIVER_FEATURES_SEL
);
141 writel((u32
)vdev
->features
,
142 vm_dev
->base
+ VIRTIO_MMIO_DRIVER_FEATURES
);
147 static void vm_get(struct virtio_device
*vdev
, unsigned offset
,
148 void *buf
, unsigned len
)
150 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
151 void __iomem
*base
= vm_dev
->base
+ VIRTIO_MMIO_CONFIG
;
156 if (vm_dev
->version
== 1) {
160 for (i
= 0; i
< len
; i
++)
161 ptr
[i
] = readb(base
+ offset
+ i
);
167 b
= readb(base
+ offset
);
168 memcpy(buf
, &b
, sizeof b
);
171 w
= cpu_to_le16(readw(base
+ offset
));
172 memcpy(buf
, &w
, sizeof w
);
175 l
= cpu_to_le32(readl(base
+ offset
));
176 memcpy(buf
, &l
, sizeof l
);
179 l
= cpu_to_le32(readl(base
+ offset
));
180 memcpy(buf
, &l
, sizeof l
);
181 l
= cpu_to_le32(ioread32(base
+ offset
+ sizeof l
));
182 memcpy(buf
+ sizeof l
, &l
, sizeof l
);
189 static void vm_set(struct virtio_device
*vdev
, unsigned offset
,
190 const void *buf
, unsigned len
)
192 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
193 void __iomem
*base
= vm_dev
->base
+ VIRTIO_MMIO_CONFIG
;
198 if (vm_dev
->version
== 1) {
202 for (i
= 0; i
< len
; i
++)
203 writeb(ptr
[i
], base
+ offset
+ i
);
210 memcpy(&b
, buf
, sizeof b
);
211 writeb(b
, base
+ offset
);
214 memcpy(&w
, buf
, sizeof w
);
215 writew(le16_to_cpu(w
), base
+ offset
);
218 memcpy(&l
, buf
, sizeof l
);
219 writel(le32_to_cpu(l
), base
+ offset
);
222 memcpy(&l
, buf
, sizeof l
);
223 writel(le32_to_cpu(l
), base
+ offset
);
224 memcpy(&l
, buf
+ sizeof l
, sizeof l
);
225 writel(le32_to_cpu(l
), base
+ offset
+ sizeof l
);
232 static u32
vm_generation(struct virtio_device
*vdev
)
234 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
236 if (vm_dev
->version
== 1)
239 return readl(vm_dev
->base
+ VIRTIO_MMIO_CONFIG_GENERATION
);
242 static u8
vm_get_status(struct virtio_device
*vdev
)
244 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
246 return readl(vm_dev
->base
+ VIRTIO_MMIO_STATUS
) & 0xff;
249 static void vm_set_status(struct virtio_device
*vdev
, u8 status
)
251 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
253 /* We should never be setting status to 0. */
256 writel(status
, vm_dev
->base
+ VIRTIO_MMIO_STATUS
);
259 static void vm_reset(struct virtio_device
*vdev
)
261 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
263 /* 0 status means a reset. */
264 writel(0, vm_dev
->base
+ VIRTIO_MMIO_STATUS
);
269 /* Transport interface */
271 /* the notify function used when creating a virt queue */
272 static bool vm_notify(struct virtqueue
*vq
)
274 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vq
->vdev
);
276 /* We write the queue's selector into the notification register to
277 * signal the other end */
278 writel(vq
->index
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_NOTIFY
);
282 /* Notify all virtqueues on an interrupt. */
283 static irqreturn_t
vm_interrupt(int irq
, void *opaque
)
285 struct virtio_mmio_device
*vm_dev
= opaque
;
286 struct virtio_mmio_vq_info
*info
;
287 unsigned long status
;
289 irqreturn_t ret
= IRQ_NONE
;
291 /* Read and acknowledge interrupts */
292 status
= readl(vm_dev
->base
+ VIRTIO_MMIO_INTERRUPT_STATUS
);
293 writel(status
, vm_dev
->base
+ VIRTIO_MMIO_INTERRUPT_ACK
);
295 if (unlikely(status
& VIRTIO_MMIO_INT_CONFIG
)) {
296 virtio_config_changed(&vm_dev
->vdev
);
300 if (likely(status
& VIRTIO_MMIO_INT_VRING
)) {
301 spin_lock_irqsave(&vm_dev
->lock
, flags
);
302 list_for_each_entry(info
, &vm_dev
->virtqueues
, node
)
303 ret
|= vring_interrupt(irq
, info
->vq
);
304 spin_unlock_irqrestore(&vm_dev
->lock
, flags
);
312 static void vm_del_vq(struct virtqueue
*vq
)
314 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vq
->vdev
);
315 struct virtio_mmio_vq_info
*info
= vq
->priv
;
317 unsigned int index
= vq
->index
;
319 spin_lock_irqsave(&vm_dev
->lock
, flags
);
320 list_del(&info
->node
);
321 spin_unlock_irqrestore(&vm_dev
->lock
, flags
);
323 /* Select and deactivate the queue */
324 writel(index
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_SEL
);
325 if (vm_dev
->version
== 1) {
326 writel(0, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_PFN
);
328 writel(0, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_READY
);
329 WARN_ON(readl(vm_dev
->base
+ VIRTIO_MMIO_QUEUE_READY
));
332 vring_del_virtqueue(vq
);
337 static void vm_del_vqs(struct virtio_device
*vdev
)
339 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
340 struct virtqueue
*vq
, *n
;
342 list_for_each_entry_safe(vq
, n
, &vdev
->vqs
, list
)
345 free_irq(platform_get_irq(vm_dev
->pdev
, 0), vm_dev
);
348 static struct virtqueue
*vm_setup_vq(struct virtio_device
*vdev
, unsigned index
,
349 void (*callback
)(struct virtqueue
*vq
),
350 const char *name
, bool ctx
)
352 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
353 struct virtio_mmio_vq_info
*info
;
354 struct virtqueue
*vq
;
362 /* Select the queue we're interested in */
363 writel(index
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_SEL
);
365 /* Queue shouldn't already be set up. */
366 if (readl(vm_dev
->base
+ (vm_dev
->version
== 1 ?
367 VIRTIO_MMIO_QUEUE_PFN
: VIRTIO_MMIO_QUEUE_READY
))) {
369 goto error_available
;
372 /* Allocate and fill out our active queue description */
373 info
= kmalloc(sizeof(*info
), GFP_KERNEL
);
379 num
= readl(vm_dev
->base
+ VIRTIO_MMIO_QUEUE_NUM_MAX
);
382 goto error_new_virtqueue
;
385 /* Create the vring */
386 vq
= vring_create_virtqueue(index
, num
, VIRTIO_MMIO_VRING_ALIGN
, vdev
,
387 true, true, ctx
, vm_notify
, callback
, name
);
390 goto error_new_virtqueue
;
393 /* Activate the queue */
394 writel(virtqueue_get_vring_size(vq
), vm_dev
->base
+ VIRTIO_MMIO_QUEUE_NUM
);
395 if (vm_dev
->version
== 1) {
396 u64 q_pfn
= virtqueue_get_desc_addr(vq
) >> PAGE_SHIFT
;
399 * virtio-mmio v1 uses a 32bit QUEUE PFN. If we have something
400 * that doesn't fit in 32bit, fail the setup rather than
401 * pretending to be successful.
405 "platform bug: legacy virtio-mmio must not be used with RAM above 0x%llxGB\n",
406 0x1ULL
<< (32 + PAGE_SHIFT
- 30));
411 writel(PAGE_SIZE
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_ALIGN
);
412 writel(q_pfn
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_PFN
);
416 addr
= virtqueue_get_desc_addr(vq
);
417 writel((u32
)addr
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_DESC_LOW
);
418 writel((u32
)(addr
>> 32),
419 vm_dev
->base
+ VIRTIO_MMIO_QUEUE_DESC_HIGH
);
421 addr
= virtqueue_get_avail_addr(vq
);
422 writel((u32
)addr
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_AVAIL_LOW
);
423 writel((u32
)(addr
>> 32),
424 vm_dev
->base
+ VIRTIO_MMIO_QUEUE_AVAIL_HIGH
);
426 addr
= virtqueue_get_used_addr(vq
);
427 writel((u32
)addr
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_USED_LOW
);
428 writel((u32
)(addr
>> 32),
429 vm_dev
->base
+ VIRTIO_MMIO_QUEUE_USED_HIGH
);
431 writel(1, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_READY
);
437 spin_lock_irqsave(&vm_dev
->lock
, flags
);
438 list_add(&info
->node
, &vm_dev
->virtqueues
);
439 spin_unlock_irqrestore(&vm_dev
->lock
, flags
);
444 vring_del_virtqueue(vq
);
446 if (vm_dev
->version
== 1) {
447 writel(0, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_PFN
);
449 writel(0, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_READY
);
450 WARN_ON(readl(vm_dev
->base
+ VIRTIO_MMIO_QUEUE_READY
));
458 static int vm_find_vqs(struct virtio_device
*vdev
, unsigned nvqs
,
459 struct virtqueue
*vqs
[],
460 vq_callback_t
*callbacks
[],
461 const char * const names
[],
463 struct irq_affinity
*desc
)
465 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
466 unsigned int irq
= platform_get_irq(vm_dev
->pdev
, 0);
467 int i
, err
, queue_idx
= 0;
469 err
= request_irq(irq
, vm_interrupt
, IRQF_SHARED
,
470 dev_name(&vdev
->dev
), vm_dev
);
474 for (i
= 0; i
< nvqs
; ++i
) {
480 vqs
[i
] = vm_setup_vq(vdev
, queue_idx
++, callbacks
[i
], names
[i
],
481 ctx
? ctx
[i
] : false);
482 if (IS_ERR(vqs
[i
])) {
484 return PTR_ERR(vqs
[i
]);
491 static const char *vm_bus_name(struct virtio_device
*vdev
)
493 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
495 return vm_dev
->pdev
->name
;
498 static const struct virtio_config_ops virtio_mmio_config_ops
= {
501 .generation
= vm_generation
,
502 .get_status
= vm_get_status
,
503 .set_status
= vm_set_status
,
505 .find_vqs
= vm_find_vqs
,
506 .del_vqs
= vm_del_vqs
,
507 .get_features
= vm_get_features
,
508 .finalize_features
= vm_finalize_features
,
509 .bus_name
= vm_bus_name
,
513 static void virtio_mmio_release_dev(struct device
*_d
)
515 struct virtio_device
*vdev
=
516 container_of(_d
, struct virtio_device
, dev
);
517 struct virtio_mmio_device
*vm_dev
=
518 container_of(vdev
, struct virtio_mmio_device
, vdev
);
519 struct platform_device
*pdev
= vm_dev
->pdev
;
521 devm_kfree(&pdev
->dev
, vm_dev
);
524 /* Platform device */
526 static int virtio_mmio_probe(struct platform_device
*pdev
)
528 struct virtio_mmio_device
*vm_dev
;
529 struct resource
*mem
;
533 mem
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
537 if (!devm_request_mem_region(&pdev
->dev
, mem
->start
,
538 resource_size(mem
), pdev
->name
))
541 vm_dev
= devm_kzalloc(&pdev
->dev
, sizeof(*vm_dev
), GFP_KERNEL
);
545 vm_dev
->vdev
.dev
.parent
= &pdev
->dev
;
546 vm_dev
->vdev
.dev
.release
= virtio_mmio_release_dev
;
547 vm_dev
->vdev
.config
= &virtio_mmio_config_ops
;
549 INIT_LIST_HEAD(&vm_dev
->virtqueues
);
550 spin_lock_init(&vm_dev
->lock
);
552 vm_dev
->base
= devm_ioremap(&pdev
->dev
, mem
->start
, resource_size(mem
));
553 if (vm_dev
->base
== NULL
)
556 /* Check magic value */
557 magic
= readl(vm_dev
->base
+ VIRTIO_MMIO_MAGIC_VALUE
);
558 if (magic
!= ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
559 dev_warn(&pdev
->dev
, "Wrong magic value 0x%08lx!\n", magic
);
563 /* Check device version */
564 vm_dev
->version
= readl(vm_dev
->base
+ VIRTIO_MMIO_VERSION
);
565 if (vm_dev
->version
< 1 || vm_dev
->version
> 2) {
566 dev_err(&pdev
->dev
, "Version %ld not supported!\n",
571 vm_dev
->vdev
.id
.device
= readl(vm_dev
->base
+ VIRTIO_MMIO_DEVICE_ID
);
572 if (vm_dev
->vdev
.id
.device
== 0) {
574 * virtio-mmio device with an ID 0 is a (dummy) placeholder
575 * with no function. End probing now with no error reported.
579 vm_dev
->vdev
.id
.vendor
= readl(vm_dev
->base
+ VIRTIO_MMIO_VENDOR_ID
);
581 if (vm_dev
->version
== 1) {
582 writel(PAGE_SIZE
, vm_dev
->base
+ VIRTIO_MMIO_GUEST_PAGE_SIZE
);
584 rc
= dma_set_mask(&pdev
->dev
, DMA_BIT_MASK(64));
586 * In the legacy case, ensure our coherently-allocated virtio
587 * ring will be at an address expressable as a 32-bit PFN.
590 dma_set_coherent_mask(&pdev
->dev
,
591 DMA_BIT_MASK(32 + PAGE_SHIFT
));
593 rc
= dma_set_mask_and_coherent(&pdev
->dev
, DMA_BIT_MASK(64));
596 rc
= dma_set_mask_and_coherent(&pdev
->dev
, DMA_BIT_MASK(32));
598 dev_warn(&pdev
->dev
, "Failed to enable 64-bit or 32-bit DMA. Trying to continue, but this might not work.\n");
600 platform_set_drvdata(pdev
, vm_dev
);
602 rc
= register_virtio_device(&vm_dev
->vdev
);
604 put_device(&vm_dev
->vdev
.dev
);
609 static int virtio_mmio_remove(struct platform_device
*pdev
)
611 struct virtio_mmio_device
*vm_dev
= platform_get_drvdata(pdev
);
612 unregister_virtio_device(&vm_dev
->vdev
);
619 /* Devices list parameter */
621 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
623 static struct device vm_cmdline_parent
= {
624 .init_name
= "virtio-mmio-cmdline",
627 static int vm_cmdline_parent_registered
;
628 static int vm_cmdline_id
;
630 static int vm_cmdline_set(const char *device
,
631 const struct kernel_param
*kp
)
634 struct resource resources
[2] = {};
636 long long int base
, size
;
638 int processed
, consumed
= 0;
639 struct platform_device
*pdev
;
641 /* Consume "size" part of the command line parameter */
642 size
= memparse(device
, &str
);
644 /* Get "@<base>:<irq>[:<id>]" chunks */
645 processed
= sscanf(str
, "@%lli:%u%n:%d%n",
646 &base
, &irq
, &consumed
,
647 &vm_cmdline_id
, &consumed
);
650 * sscanf() must processes at least 2 chunks; also there
651 * must be no extra characters after the last chunk, so
652 * str[consumed] must be '\0'
654 if (processed
< 2 || str
[consumed
])
657 resources
[0].flags
= IORESOURCE_MEM
;
658 resources
[0].start
= base
;
659 resources
[0].end
= base
+ size
- 1;
661 resources
[1].flags
= IORESOURCE_IRQ
;
662 resources
[1].start
= resources
[1].end
= irq
;
664 if (!vm_cmdline_parent_registered
) {
665 err
= device_register(&vm_cmdline_parent
);
667 pr_err("Failed to register parent device!\n");
670 vm_cmdline_parent_registered
= 1;
673 pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
675 (unsigned long long)resources
[0].start
,
676 (unsigned long long)resources
[0].end
,
677 (int)resources
[1].start
);
679 pdev
= platform_device_register_resndata(&vm_cmdline_parent
,
680 "virtio-mmio", vm_cmdline_id
++,
681 resources
, ARRAY_SIZE(resources
), NULL
, 0);
683 return PTR_ERR_OR_ZERO(pdev
);
686 static int vm_cmdline_get_device(struct device
*dev
, void *data
)
689 unsigned int len
= strlen(buffer
);
690 struct platform_device
*pdev
= to_platform_device(dev
);
692 snprintf(buffer
+ len
, PAGE_SIZE
- len
, "0x%llx@0x%llx:%llu:%d\n",
693 pdev
->resource
[0].end
- pdev
->resource
[0].start
+ 1ULL,
694 (unsigned long long)pdev
->resource
[0].start
,
695 (unsigned long long)pdev
->resource
[1].start
,
700 static int vm_cmdline_get(char *buffer
, const struct kernel_param
*kp
)
703 device_for_each_child(&vm_cmdline_parent
, buffer
,
704 vm_cmdline_get_device
);
705 return strlen(buffer
) + 1;
708 static const struct kernel_param_ops vm_cmdline_param_ops
= {
709 .set
= vm_cmdline_set
,
710 .get
= vm_cmdline_get
,
713 device_param_cb(device
, &vm_cmdline_param_ops
, NULL
, S_IRUSR
);
715 static int vm_unregister_cmdline_device(struct device
*dev
,
718 platform_device_unregister(to_platform_device(dev
));
723 static void vm_unregister_cmdline_devices(void)
725 if (vm_cmdline_parent_registered
) {
726 device_for_each_child(&vm_cmdline_parent
, NULL
,
727 vm_unregister_cmdline_device
);
728 device_unregister(&vm_cmdline_parent
);
729 vm_cmdline_parent_registered
= 0;
735 static void vm_unregister_cmdline_devices(void)
741 /* Platform driver */
743 static const struct of_device_id virtio_mmio_match
[] = {
744 { .compatible
= "virtio,mmio", },
747 MODULE_DEVICE_TABLE(of
, virtio_mmio_match
);
750 static const struct acpi_device_id virtio_mmio_acpi_match
[] = {
754 MODULE_DEVICE_TABLE(acpi
, virtio_mmio_acpi_match
);
757 static struct platform_driver virtio_mmio_driver
= {
758 .probe
= virtio_mmio_probe
,
759 .remove
= virtio_mmio_remove
,
761 .name
= "virtio-mmio",
762 .of_match_table
= virtio_mmio_match
,
763 .acpi_match_table
= ACPI_PTR(virtio_mmio_acpi_match
),
767 static int __init
virtio_mmio_init(void)
769 return platform_driver_register(&virtio_mmio_driver
);
772 static void __exit
virtio_mmio_exit(void)
774 platform_driver_unregister(&virtio_mmio_driver
);
775 vm_unregister_cmdline_devices();
778 module_init(virtio_mmio_init
);
779 module_exit(virtio_mmio_exit
);
781 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
782 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
783 MODULE_LICENSE("GPL");