2 * Virtio memory mapped device driver
4 * Copyright 2011-2014, ARM Ltd.
6 * This module allows virtio devices to be used over a virtual, memory mapped
9 * The guest device(s) may be instantiated in one of three equivalent ways:
11 * 1. Static platform device in board's code, eg.:
13 * static struct platform_device v2m_virtio_device = {
14 * .name = "virtio-mmio",
17 * .resource = (struct resource []) {
19 * .start = 0x1001e000,
21 * .flags = IORESOURCE_MEM,
25 * .flags = IORESOURCE_IRQ,
30 * 2. Device Tree node, eg.:
32 * virtio_block@1e000 {
33 * compatible = "virtio,mmio";
34 * reg = <0x1e000 0x100>;
38 * 3. Kernel module (or command line) parameter. Can be used more than once -
39 * one device will be created for each one. Syntax:
41 * [virtio_mmio.]device=<size>@<baseaddr>:<irq>[:<id>]
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
48 * virtio_mmio.device=0x100@0x100b0000:48 \
49 * virtio_mmio.device=1K@0x1001e000:74
53 * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
55 * This work is licensed under the terms of the GNU GPL, version 2 or later.
56 * See the COPYING file in the top-level directory.
59 #define pr_fmt(fmt) "virtio-mmio: " fmt
61 #include <linux/acpi.h>
62 #include <linux/dma-mapping.h>
63 #include <linux/highmem.h>
64 #include <linux/interrupt.h>
66 #include <linux/list.h>
67 #include <linux/module.h>
68 #include <linux/platform_device.h>
69 #include <linux/slab.h>
70 #include <linux/spinlock.h>
71 #include <linux/virtio.h>
72 #include <linux/virtio_config.h>
73 #include <linux/virtio_mmio.h>
74 #include <linux/virtio_ring.h>
78 /* The alignment to use between consumer and producer parts of vring.
79 * Currently hardcoded to the page size. */
80 #define VIRTIO_MMIO_VRING_ALIGN PAGE_SIZE
84 #define to_virtio_mmio_device(_plat_dev) \
85 container_of(_plat_dev, struct virtio_mmio_device, vdev)
87 struct virtio_mmio_device
{
88 struct virtio_device vdev
;
89 struct platform_device
*pdev
;
92 unsigned long version
;
94 /* a list of queues so we can dispatch IRQs */
96 struct list_head virtqueues
;
99 struct virtio_mmio_vq_info
{
100 /* the actual virtqueue */
101 struct virtqueue
*vq
;
103 /* the list node for the virtqueues list */
104 struct list_head node
;
109 /* Configuration interface */
111 static u64
vm_get_features(struct virtio_device
*vdev
)
113 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
116 writel(1, vm_dev
->base
+ VIRTIO_MMIO_DEVICE_FEATURES_SEL
);
117 features
= readl(vm_dev
->base
+ VIRTIO_MMIO_DEVICE_FEATURES
);
120 writel(0, vm_dev
->base
+ VIRTIO_MMIO_DEVICE_FEATURES_SEL
);
121 features
|= readl(vm_dev
->base
+ VIRTIO_MMIO_DEVICE_FEATURES
);
126 static int vm_finalize_features(struct virtio_device
*vdev
)
128 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
130 /* Give virtio_ring a chance to accept features. */
131 vring_transport_features(vdev
);
133 /* Make sure there is are no mixed devices */
134 if (vm_dev
->version
== 2 &&
135 !__virtio_test_bit(vdev
, VIRTIO_F_VERSION_1
)) {
136 dev_err(&vdev
->dev
, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n");
140 writel(1, vm_dev
->base
+ VIRTIO_MMIO_DRIVER_FEATURES_SEL
);
141 writel((u32
)(vdev
->features
>> 32),
142 vm_dev
->base
+ VIRTIO_MMIO_DRIVER_FEATURES
);
144 writel(0, vm_dev
->base
+ VIRTIO_MMIO_DRIVER_FEATURES_SEL
);
145 writel((u32
)vdev
->features
,
146 vm_dev
->base
+ VIRTIO_MMIO_DRIVER_FEATURES
);
151 static void vm_get(struct virtio_device
*vdev
, unsigned offset
,
152 void *buf
, unsigned len
)
154 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
155 void __iomem
*base
= vm_dev
->base
+ VIRTIO_MMIO_CONFIG
;
160 if (vm_dev
->version
== 1) {
164 for (i
= 0; i
< len
; i
++)
165 ptr
[i
] = readb(base
+ offset
+ i
);
171 b
= readb(base
+ offset
);
172 memcpy(buf
, &b
, sizeof b
);
175 w
= cpu_to_le16(readw(base
+ offset
));
176 memcpy(buf
, &w
, sizeof w
);
179 l
= cpu_to_le32(readl(base
+ offset
));
180 memcpy(buf
, &l
, sizeof l
);
183 l
= cpu_to_le32(readl(base
+ offset
));
184 memcpy(buf
, &l
, sizeof l
);
185 l
= cpu_to_le32(ioread32(base
+ offset
+ sizeof l
));
186 memcpy(buf
+ sizeof l
, &l
, sizeof l
);
193 static void vm_set(struct virtio_device
*vdev
, unsigned offset
,
194 const void *buf
, unsigned len
)
196 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
197 void __iomem
*base
= vm_dev
->base
+ VIRTIO_MMIO_CONFIG
;
202 if (vm_dev
->version
== 1) {
206 for (i
= 0; i
< len
; i
++)
207 writeb(ptr
[i
], base
+ offset
+ i
);
214 memcpy(&b
, buf
, sizeof b
);
215 writeb(b
, base
+ offset
);
218 memcpy(&w
, buf
, sizeof w
);
219 writew(le16_to_cpu(w
), base
+ offset
);
222 memcpy(&l
, buf
, sizeof l
);
223 writel(le32_to_cpu(l
), base
+ offset
);
226 memcpy(&l
, buf
, sizeof l
);
227 writel(le32_to_cpu(l
), base
+ offset
);
228 memcpy(&l
, buf
+ sizeof l
, sizeof l
);
229 writel(le32_to_cpu(l
), base
+ offset
+ sizeof l
);
236 static u32
vm_generation(struct virtio_device
*vdev
)
238 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
240 if (vm_dev
->version
== 1)
243 return readl(vm_dev
->base
+ VIRTIO_MMIO_CONFIG_GENERATION
);
246 static u8
vm_get_status(struct virtio_device
*vdev
)
248 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
250 return readl(vm_dev
->base
+ VIRTIO_MMIO_STATUS
) & 0xff;
253 static void vm_set_status(struct virtio_device
*vdev
, u8 status
)
255 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
257 /* We should never be setting status to 0. */
260 writel(status
, vm_dev
->base
+ VIRTIO_MMIO_STATUS
);
263 static void vm_reset(struct virtio_device
*vdev
)
265 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
267 /* 0 status means a reset. */
268 writel(0, vm_dev
->base
+ VIRTIO_MMIO_STATUS
);
273 /* Transport interface */
275 /* the notify function used when creating a virt queue */
276 static bool vm_notify(struct virtqueue
*vq
)
278 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vq
->vdev
);
280 /* We write the queue's selector into the notification register to
281 * signal the other end */
282 writel(vq
->index
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_NOTIFY
);
286 /* Notify all virtqueues on an interrupt. */
287 static irqreturn_t
vm_interrupt(int irq
, void *opaque
)
289 struct virtio_mmio_device
*vm_dev
= opaque
;
290 struct virtio_mmio_vq_info
*info
;
291 unsigned long status
;
293 irqreturn_t ret
= IRQ_NONE
;
295 /* Read and acknowledge interrupts */
296 status
= readl(vm_dev
->base
+ VIRTIO_MMIO_INTERRUPT_STATUS
);
297 writel(status
, vm_dev
->base
+ VIRTIO_MMIO_INTERRUPT_ACK
);
299 if (unlikely(status
& VIRTIO_MMIO_INT_CONFIG
)) {
300 virtio_config_changed(&vm_dev
->vdev
);
304 if (likely(status
& VIRTIO_MMIO_INT_VRING
)) {
305 spin_lock_irqsave(&vm_dev
->lock
, flags
);
306 list_for_each_entry(info
, &vm_dev
->virtqueues
, node
)
307 ret
|= vring_interrupt(irq
, info
->vq
);
308 spin_unlock_irqrestore(&vm_dev
->lock
, flags
);
316 static void vm_del_vq(struct virtqueue
*vq
)
318 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vq
->vdev
);
319 struct virtio_mmio_vq_info
*info
= vq
->priv
;
321 unsigned int index
= vq
->index
;
323 spin_lock_irqsave(&vm_dev
->lock
, flags
);
324 list_del(&info
->node
);
325 spin_unlock_irqrestore(&vm_dev
->lock
, flags
);
327 /* Select and deactivate the queue */
328 writel(index
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_SEL
);
329 if (vm_dev
->version
== 1) {
330 writel(0, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_PFN
);
332 writel(0, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_READY
);
333 WARN_ON(readl(vm_dev
->base
+ VIRTIO_MMIO_QUEUE_READY
));
336 vring_del_virtqueue(vq
);
341 static void vm_del_vqs(struct virtio_device
*vdev
)
343 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
344 struct virtqueue
*vq
, *n
;
346 list_for_each_entry_safe(vq
, n
, &vdev
->vqs
, list
)
349 free_irq(platform_get_irq(vm_dev
->pdev
, 0), vm_dev
);
352 static struct virtqueue
*vm_setup_vq(struct virtio_device
*vdev
, unsigned index
,
353 void (*callback
)(struct virtqueue
*vq
),
356 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
357 struct virtio_mmio_vq_info
*info
;
358 struct virtqueue
*vq
;
366 /* Select the queue we're interested in */
367 writel(index
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_SEL
);
369 /* Queue shouldn't already be set up. */
370 if (readl(vm_dev
->base
+ (vm_dev
->version
== 1 ?
371 VIRTIO_MMIO_QUEUE_PFN
: VIRTIO_MMIO_QUEUE_READY
))) {
373 goto error_available
;
376 /* Allocate and fill out our active queue description */
377 info
= kmalloc(sizeof(*info
), GFP_KERNEL
);
383 num
= readl(vm_dev
->base
+ VIRTIO_MMIO_QUEUE_NUM_MAX
);
386 goto error_new_virtqueue
;
389 /* Create the vring */
390 vq
= vring_create_virtqueue(index
, num
, VIRTIO_MMIO_VRING_ALIGN
, vdev
,
391 true, true, vm_notify
, callback
, name
);
394 goto error_new_virtqueue
;
397 /* Activate the queue */
398 writel(virtqueue_get_vring_size(vq
), vm_dev
->base
+ VIRTIO_MMIO_QUEUE_NUM
);
399 if (vm_dev
->version
== 1) {
400 writel(PAGE_SIZE
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_ALIGN
);
401 writel(virtqueue_get_desc_addr(vq
) >> PAGE_SHIFT
,
402 vm_dev
->base
+ VIRTIO_MMIO_QUEUE_PFN
);
406 addr
= virtqueue_get_desc_addr(vq
);
407 writel((u32
)addr
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_DESC_LOW
);
408 writel((u32
)(addr
>> 32),
409 vm_dev
->base
+ VIRTIO_MMIO_QUEUE_DESC_HIGH
);
411 addr
= virtqueue_get_avail_addr(vq
);
412 writel((u32
)addr
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_AVAIL_LOW
);
413 writel((u32
)(addr
>> 32),
414 vm_dev
->base
+ VIRTIO_MMIO_QUEUE_AVAIL_HIGH
);
416 addr
= virtqueue_get_used_addr(vq
);
417 writel((u32
)addr
, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_USED_LOW
);
418 writel((u32
)(addr
>> 32),
419 vm_dev
->base
+ VIRTIO_MMIO_QUEUE_USED_HIGH
);
421 writel(1, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_READY
);
427 spin_lock_irqsave(&vm_dev
->lock
, flags
);
428 list_add(&info
->node
, &vm_dev
->virtqueues
);
429 spin_unlock_irqrestore(&vm_dev
->lock
, flags
);
434 if (vm_dev
->version
== 1) {
435 writel(0, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_PFN
);
437 writel(0, vm_dev
->base
+ VIRTIO_MMIO_QUEUE_READY
);
438 WARN_ON(readl(vm_dev
->base
+ VIRTIO_MMIO_QUEUE_READY
));
446 static int vm_find_vqs(struct virtio_device
*vdev
, unsigned nvqs
,
447 struct virtqueue
*vqs
[],
448 vq_callback_t
*callbacks
[],
449 const char * const names
[])
451 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
452 unsigned int irq
= platform_get_irq(vm_dev
->pdev
, 0);
455 err
= request_irq(irq
, vm_interrupt
, IRQF_SHARED
,
456 dev_name(&vdev
->dev
), vm_dev
);
460 for (i
= 0; i
< nvqs
; ++i
) {
461 vqs
[i
] = vm_setup_vq(vdev
, i
, callbacks
[i
], names
[i
]);
462 if (IS_ERR(vqs
[i
])) {
464 return PTR_ERR(vqs
[i
]);
471 static const char *vm_bus_name(struct virtio_device
*vdev
)
473 struct virtio_mmio_device
*vm_dev
= to_virtio_mmio_device(vdev
);
475 return vm_dev
->pdev
->name
;
478 static const struct virtio_config_ops virtio_mmio_config_ops
= {
481 .generation
= vm_generation
,
482 .get_status
= vm_get_status
,
483 .set_status
= vm_set_status
,
485 .find_vqs
= vm_find_vqs
,
486 .del_vqs
= vm_del_vqs
,
487 .get_features
= vm_get_features
,
488 .finalize_features
= vm_finalize_features
,
489 .bus_name
= vm_bus_name
,
493 static void virtio_mmio_release_dev_empty(struct device
*_d
) {}
495 /* Platform device */
497 static int virtio_mmio_probe(struct platform_device
*pdev
)
499 struct virtio_mmio_device
*vm_dev
;
500 struct resource
*mem
;
504 mem
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
508 if (!devm_request_mem_region(&pdev
->dev
, mem
->start
,
509 resource_size(mem
), pdev
->name
))
512 vm_dev
= devm_kzalloc(&pdev
->dev
, sizeof(*vm_dev
), GFP_KERNEL
);
516 vm_dev
->vdev
.dev
.parent
= &pdev
->dev
;
517 vm_dev
->vdev
.dev
.release
= virtio_mmio_release_dev_empty
;
518 vm_dev
->vdev
.config
= &virtio_mmio_config_ops
;
520 INIT_LIST_HEAD(&vm_dev
->virtqueues
);
521 spin_lock_init(&vm_dev
->lock
);
523 vm_dev
->base
= devm_ioremap(&pdev
->dev
, mem
->start
, resource_size(mem
));
524 if (vm_dev
->base
== NULL
)
527 /* Check magic value */
528 magic
= readl(vm_dev
->base
+ VIRTIO_MMIO_MAGIC_VALUE
);
529 if (magic
!= ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
530 dev_warn(&pdev
->dev
, "Wrong magic value 0x%08lx!\n", magic
);
534 /* Check device version */
535 vm_dev
->version
= readl(vm_dev
->base
+ VIRTIO_MMIO_VERSION
);
536 if (vm_dev
->version
< 1 || vm_dev
->version
> 2) {
537 dev_err(&pdev
->dev
, "Version %ld not supported!\n",
542 vm_dev
->vdev
.id
.device
= readl(vm_dev
->base
+ VIRTIO_MMIO_DEVICE_ID
);
543 if (vm_dev
->vdev
.id
.device
== 0) {
545 * virtio-mmio device with an ID 0 is a (dummy) placeholder
546 * with no function. End probing now with no error reported.
550 vm_dev
->vdev
.id
.vendor
= readl(vm_dev
->base
+ VIRTIO_MMIO_VENDOR_ID
);
552 if (vm_dev
->version
== 1) {
553 writel(PAGE_SIZE
, vm_dev
->base
+ VIRTIO_MMIO_GUEST_PAGE_SIZE
);
555 rc
= dma_set_mask(&pdev
->dev
, DMA_BIT_MASK(64));
557 * In the legacy case, ensure our coherently-allocated virtio
558 * ring will be at an address expressable as a 32-bit PFN.
561 dma_set_coherent_mask(&pdev
->dev
,
562 DMA_BIT_MASK(32 + PAGE_SHIFT
));
564 rc
= dma_set_mask_and_coherent(&pdev
->dev
, DMA_BIT_MASK(64));
567 rc
= dma_set_mask_and_coherent(&pdev
->dev
, DMA_BIT_MASK(32));
569 dev_warn(&pdev
->dev
, "Failed to enable 64-bit or 32-bit DMA. Trying to continue, but this might not work.\n");
571 platform_set_drvdata(pdev
, vm_dev
);
573 return register_virtio_device(&vm_dev
->vdev
);
576 static int virtio_mmio_remove(struct platform_device
*pdev
)
578 struct virtio_mmio_device
*vm_dev
= platform_get_drvdata(pdev
);
580 unregister_virtio_device(&vm_dev
->vdev
);
587 /* Devices list parameter */
589 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
591 static struct device vm_cmdline_parent
= {
592 .init_name
= "virtio-mmio-cmdline",
595 static int vm_cmdline_parent_registered
;
596 static int vm_cmdline_id
;
598 static int vm_cmdline_set(const char *device
,
599 const struct kernel_param
*kp
)
602 struct resource resources
[2] = {};
604 long long int base
, size
;
606 int processed
, consumed
= 0;
607 struct platform_device
*pdev
;
609 /* Consume "size" part of the command line parameter */
610 size
= memparse(device
, &str
);
612 /* Get "@<base>:<irq>[:<id>]" chunks */
613 processed
= sscanf(str
, "@%lli:%u%n:%d%n",
614 &base
, &irq
, &consumed
,
615 &vm_cmdline_id
, &consumed
);
618 * sscanf() must processes at least 2 chunks; also there
619 * must be no extra characters after the last chunk, so
620 * str[consumed] must be '\0'
622 if (processed
< 2 || str
[consumed
])
625 resources
[0].flags
= IORESOURCE_MEM
;
626 resources
[0].start
= base
;
627 resources
[0].end
= base
+ size
- 1;
629 resources
[1].flags
= IORESOURCE_IRQ
;
630 resources
[1].start
= resources
[1].end
= irq
;
632 if (!vm_cmdline_parent_registered
) {
633 err
= device_register(&vm_cmdline_parent
);
635 pr_err("Failed to register parent device!\n");
638 vm_cmdline_parent_registered
= 1;
641 pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
643 (unsigned long long)resources
[0].start
,
644 (unsigned long long)resources
[0].end
,
645 (int)resources
[1].start
);
647 pdev
= platform_device_register_resndata(&vm_cmdline_parent
,
648 "virtio-mmio", vm_cmdline_id
++,
649 resources
, ARRAY_SIZE(resources
), NULL
, 0);
651 return PTR_ERR(pdev
);
656 static int vm_cmdline_get_device(struct device
*dev
, void *data
)
659 unsigned int len
= strlen(buffer
);
660 struct platform_device
*pdev
= to_platform_device(dev
);
662 snprintf(buffer
+ len
, PAGE_SIZE
- len
, "0x%llx@0x%llx:%llu:%d\n",
663 pdev
->resource
[0].end
- pdev
->resource
[0].start
+ 1ULL,
664 (unsigned long long)pdev
->resource
[0].start
,
665 (unsigned long long)pdev
->resource
[1].start
,
670 static int vm_cmdline_get(char *buffer
, const struct kernel_param
*kp
)
673 device_for_each_child(&vm_cmdline_parent
, buffer
,
674 vm_cmdline_get_device
);
675 return strlen(buffer
) + 1;
678 static const struct kernel_param_ops vm_cmdline_param_ops
= {
679 .set
= vm_cmdline_set
,
680 .get
= vm_cmdline_get
,
683 device_param_cb(device
, &vm_cmdline_param_ops
, NULL
, S_IRUSR
);
685 static int vm_unregister_cmdline_device(struct device
*dev
,
688 platform_device_unregister(to_platform_device(dev
));
693 static void vm_unregister_cmdline_devices(void)
695 if (vm_cmdline_parent_registered
) {
696 device_for_each_child(&vm_cmdline_parent
, NULL
,
697 vm_unregister_cmdline_device
);
698 device_unregister(&vm_cmdline_parent
);
699 vm_cmdline_parent_registered
= 0;
705 static void vm_unregister_cmdline_devices(void)
711 /* Platform driver */
713 static struct of_device_id virtio_mmio_match
[] = {
714 { .compatible
= "virtio,mmio", },
717 MODULE_DEVICE_TABLE(of
, virtio_mmio_match
);
720 static const struct acpi_device_id virtio_mmio_acpi_match
[] = {
724 MODULE_DEVICE_TABLE(acpi
, virtio_mmio_acpi_match
);
727 static struct platform_driver virtio_mmio_driver
= {
728 .probe
= virtio_mmio_probe
,
729 .remove
= virtio_mmio_remove
,
731 .name
= "virtio-mmio",
732 .of_match_table
= virtio_mmio_match
,
733 .acpi_match_table
= ACPI_PTR(virtio_mmio_acpi_match
),
737 static int __init
virtio_mmio_init(void)
739 return platform_driver_register(&virtio_mmio_driver
);
742 static void __exit
virtio_mmio_exit(void)
744 platform_driver_unregister(&virtio_mmio_driver
);
745 vm_unregister_cmdline_devices();
748 module_init(virtio_mmio_init
);
749 module_exit(virtio_mmio_exit
);
751 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
752 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
753 MODULE_LICENSE("GPL");