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>
70 #include <linux/slab.h>
71 #include <linux/spinlock.h>
72 #include <linux/virtio.h>
73 #include <linux/virtio_config.h>
74 #include <linux/virtio_mmio.h>
75 #include <linux/virtio_ring.h>
79 /* The alignment to use between consumer and producer parts of vring.
80 * Currently hardcoded to the page size. */
81 #define VIRTIO_MMIO_VRING_ALIGN PAGE_SIZE
85 #define to_virtio_mmio_device(_plat_dev) \
86 container_of(_plat_dev, struct virtio_mmio_device, vdev)
88 struct virtio_mmio_device {
89 struct virtio_device vdev;
90 struct platform_device *pdev;
93 unsigned long version;
95 /* a list of queues so we can dispatch IRQs */
97 struct list_head virtqueues;
100 struct virtio_mmio_vq_info {
101 /* the actual virtqueue */
102 struct virtqueue *vq;
104 /* the list node for the virtqueues list */
105 struct list_head node;
110 /* Configuration interface */
112 static u64 vm_get_features(struct virtio_device *vdev)
114 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
117 writel(1, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
118 features = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
121 writel(0, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
122 features |= readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
127 static int vm_finalize_features(struct virtio_device *vdev)
129 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
131 /* Give virtio_ring a chance to accept features. */
132 vring_transport_features(vdev);
134 /* Make sure there is are no mixed devices */
135 if (vm_dev->version == 2 &&
136 !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
137 dev_err(&vdev->dev, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n");
141 writel(1, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
142 writel((u32)(vdev->features >> 32),
143 vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
145 writel(0, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
146 writel((u32)vdev->features,
147 vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
152 static void vm_get(struct virtio_device *vdev, unsigned offset,
153 void *buf, unsigned len)
155 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
156 void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
161 if (vm_dev->version == 1) {
165 for (i = 0; i < len; i++)
166 ptr[i] = readb(base + offset + i);
172 b = readb(base + offset);
173 memcpy(buf, &b, sizeof b);
176 w = cpu_to_le16(readw(base + offset));
177 memcpy(buf, &w, sizeof w);
180 l = cpu_to_le32(readl(base + offset));
181 memcpy(buf, &l, sizeof l);
184 l = cpu_to_le32(readl(base + offset));
185 memcpy(buf, &l, sizeof l);
186 l = cpu_to_le32(ioread32(base + offset + sizeof l));
187 memcpy(buf + sizeof l, &l, sizeof l);
194 static void vm_set(struct virtio_device *vdev, unsigned offset,
195 const void *buf, unsigned len)
197 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
198 void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
203 if (vm_dev->version == 1) {
207 for (i = 0; i < len; i++)
208 writeb(ptr[i], base + offset + i);
215 memcpy(&b, buf, sizeof b);
216 writeb(b, base + offset);
219 memcpy(&w, buf, sizeof w);
220 writew(le16_to_cpu(w), base + offset);
223 memcpy(&l, buf, sizeof l);
224 writel(le32_to_cpu(l), base + offset);
227 memcpy(&l, buf, sizeof l);
228 writel(le32_to_cpu(l), base + offset);
229 memcpy(&l, buf + sizeof l, sizeof l);
230 writel(le32_to_cpu(l), base + offset + sizeof l);
237 static u32 vm_generation(struct virtio_device *vdev)
239 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
241 if (vm_dev->version == 1)
244 return readl(vm_dev->base + VIRTIO_MMIO_CONFIG_GENERATION);
247 static u8 vm_get_status(struct virtio_device *vdev)
249 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
251 return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
254 static void vm_set_status(struct virtio_device *vdev, u8 status)
256 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
258 /* We should never be setting status to 0. */
261 writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
264 static void vm_reset(struct virtio_device *vdev)
266 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
268 /* 0 status means a reset. */
269 writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
274 /* Transport interface */
276 /* the notify function used when creating a virt queue */
277 static bool vm_notify(struct virtqueue *vq)
279 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
281 /* We write the queue's selector into the notification register to
282 * signal the other end */
283 writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
287 /* Notify all virtqueues on an interrupt. */
288 static irqreturn_t vm_interrupt(int irq, void *opaque)
290 struct virtio_mmio_device *vm_dev = opaque;
291 struct virtio_mmio_vq_info *info;
292 unsigned long status;
294 irqreturn_t ret = IRQ_NONE;
296 /* Read and acknowledge interrupts */
297 status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
298 writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
300 if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)) {
301 virtio_config_changed(&vm_dev->vdev);
305 if (likely(status & VIRTIO_MMIO_INT_VRING)) {
306 spin_lock_irqsave(&vm_dev->lock, flags);
307 list_for_each_entry(info, &vm_dev->virtqueues, node)
308 ret |= vring_interrupt(irq, info->vq);
309 spin_unlock_irqrestore(&vm_dev->lock, flags);
317 static void vm_del_vq(struct virtqueue *vq)
319 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
320 struct virtio_mmio_vq_info *info = vq->priv;
322 unsigned int index = vq->index;
324 spin_lock_irqsave(&vm_dev->lock, flags);
325 list_del(&info->node);
326 spin_unlock_irqrestore(&vm_dev->lock, flags);
328 /* Select and deactivate the queue */
329 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
330 if (vm_dev->version == 1) {
331 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
333 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
334 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
337 vring_del_virtqueue(vq);
342 static void vm_del_vqs(struct virtio_device *vdev)
344 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
345 struct virtqueue *vq, *n;
347 list_for_each_entry_safe(vq, n, &vdev->vqs, list)
350 free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
353 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
354 void (*callback)(struct virtqueue *vq),
357 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
358 struct virtio_mmio_vq_info *info;
359 struct virtqueue *vq;
367 /* Select the queue we're interested in */
368 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
370 /* Queue shouldn't already be set up. */
371 if (readl(vm_dev->base + (vm_dev->version == 1 ?
372 VIRTIO_MMIO_QUEUE_PFN : VIRTIO_MMIO_QUEUE_READY))) {
374 goto error_available;
377 /* Allocate and fill out our active queue description */
378 info = kmalloc(sizeof(*info), GFP_KERNEL);
384 num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
387 goto error_new_virtqueue;
390 /* Create the vring */
391 vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
392 true, true, vm_notify, callback, name);
395 goto error_new_virtqueue;
398 /* Activate the queue */
399 writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
400 if (vm_dev->version == 1) {
401 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
402 writel(virtqueue_get_desc_addr(vq) >> PAGE_SHIFT,
403 vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
407 addr = virtqueue_get_desc_addr(vq);
408 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_LOW);
409 writel((u32)(addr >> 32),
410 vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_HIGH);
412 addr = virtqueue_get_avail_addr(vq);
413 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_LOW);
414 writel((u32)(addr >> 32),
415 vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_HIGH);
417 addr = virtqueue_get_used_addr(vq);
418 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_USED_LOW);
419 writel((u32)(addr >> 32),
420 vm_dev->base + VIRTIO_MMIO_QUEUE_USED_HIGH);
422 writel(1, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
428 spin_lock_irqsave(&vm_dev->lock, flags);
429 list_add(&info->node, &vm_dev->virtqueues);
430 spin_unlock_irqrestore(&vm_dev->lock, flags);
435 if (vm_dev->version == 1) {
436 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
438 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
439 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
447 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
448 struct virtqueue *vqs[],
449 vq_callback_t *callbacks[],
450 const char * const names[])
452 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
453 unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
456 err = request_irq(irq, vm_interrupt, IRQF_SHARED,
457 dev_name(&vdev->dev), vm_dev);
461 for (i = 0; i < nvqs; ++i) {
462 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
463 if (IS_ERR(vqs[i])) {
465 return PTR_ERR(vqs[i]);
472 static const char *vm_bus_name(struct virtio_device *vdev)
474 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
476 return vm_dev->pdev->name;
479 static const struct virtio_config_ops virtio_mmio_config_ops = {
482 .generation = vm_generation,
483 .get_status = vm_get_status,
484 .set_status = vm_set_status,
486 .find_vqs = vm_find_vqs,
487 .del_vqs = vm_del_vqs,
488 .get_features = vm_get_features,
489 .finalize_features = vm_finalize_features,
490 .bus_name = vm_bus_name,
493 #ifdef CONFIG_PM_SLEEP
494 static int virtio_mmio_freeze(struct device *dev)
496 struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
498 return virtio_device_freeze(&vm_dev->vdev);
501 static int virtio_mmio_restore(struct device *dev)
503 struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
505 if (vm_dev->version == 1)
506 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
508 return virtio_device_restore(&vm_dev->vdev);
511 static const struct dev_pm_ops virtio_mmio_pm_ops = {
512 SET_SYSTEM_SLEEP_PM_OPS(virtio_mmio_freeze, virtio_mmio_restore)
517 /* Platform device */
519 static int virtio_mmio_probe(struct platform_device *pdev)
521 struct virtio_mmio_device *vm_dev;
522 struct resource *mem;
526 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
530 if (!devm_request_mem_region(&pdev->dev, mem->start,
531 resource_size(mem), pdev->name))
534 vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
538 vm_dev->vdev.dev.parent = &pdev->dev;
539 vm_dev->vdev.config = &virtio_mmio_config_ops;
541 INIT_LIST_HEAD(&vm_dev->virtqueues);
542 spin_lock_init(&vm_dev->lock);
544 vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
545 if (vm_dev->base == NULL)
548 /* Check magic value */
549 magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
550 if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
551 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
555 /* Check device version */
556 vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
557 if (vm_dev->version < 1 || vm_dev->version > 2) {
558 dev_err(&pdev->dev, "Version %ld not supported!\n",
563 vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
564 if (vm_dev->vdev.id.device == 0) {
566 * virtio-mmio device with an ID 0 is a (dummy) placeholder
567 * with no function. End probing now with no error reported.
571 vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
573 if (vm_dev->version == 1) {
574 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
576 rc = dma_set_mask(&pdev->dev, DMA_BIT_MASK(64));
578 * In the legacy case, ensure our coherently-allocated virtio
579 * ring will be at an address expressable as a 32-bit PFN.
582 dma_set_coherent_mask(&pdev->dev,
583 DMA_BIT_MASK(32 + PAGE_SHIFT));
585 rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
588 rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
590 dev_warn(&pdev->dev, "Failed to enable 64-bit or 32-bit DMA. Trying to continue, but this might not work.\n");
592 platform_set_drvdata(pdev, vm_dev);
594 return register_virtio_device(&vm_dev->vdev);
597 static int virtio_mmio_remove(struct platform_device *pdev)
599 struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
601 unregister_virtio_device(&vm_dev->vdev);
608 /* Devices list parameter */
610 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
612 static struct device vm_cmdline_parent = {
613 .init_name = "virtio-mmio-cmdline",
616 static int vm_cmdline_parent_registered;
617 static int vm_cmdline_id;
619 static int vm_cmdline_set(const char *device,
620 const struct kernel_param *kp)
623 struct resource resources[2] = {};
625 long long int base, size;
627 int processed, consumed = 0;
628 struct platform_device *pdev;
630 /* Consume "size" part of the command line parameter */
631 size = memparse(device, &str);
633 /* Get "@<base>:<irq>[:<id>]" chunks */
634 processed = sscanf(str, "@%lli:%u%n:%d%n",
635 &base, &irq, &consumed,
636 &vm_cmdline_id, &consumed);
639 * sscanf() must processes at least 2 chunks; also there
640 * must be no extra characters after the last chunk, so
641 * str[consumed] must be '\0'
643 if (processed < 2 || str[consumed])
646 resources[0].flags = IORESOURCE_MEM;
647 resources[0].start = base;
648 resources[0].end = base + size - 1;
650 resources[1].flags = IORESOURCE_IRQ;
651 resources[1].start = resources[1].end = irq;
653 if (!vm_cmdline_parent_registered) {
654 err = device_register(&vm_cmdline_parent);
656 put_device(&vm_cmdline_parent);
657 pr_err("Failed to register parent device!\n");
660 vm_cmdline_parent_registered = 1;
663 pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
665 (unsigned long long)resources[0].start,
666 (unsigned long long)resources[0].end,
667 (int)resources[1].start);
669 pdev = platform_device_register_resndata(&vm_cmdline_parent,
670 "virtio-mmio", vm_cmdline_id++,
671 resources, ARRAY_SIZE(resources), NULL, 0);
673 return PTR_ERR(pdev);
678 static int vm_cmdline_get_device(struct device *dev, void *data)
681 unsigned int len = strlen(buffer);
682 struct platform_device *pdev = to_platform_device(dev);
684 snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
685 pdev->resource[0].end - pdev->resource[0].start + 1ULL,
686 (unsigned long long)pdev->resource[0].start,
687 (unsigned long long)pdev->resource[1].start,
692 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
695 device_for_each_child(&vm_cmdline_parent, buffer,
696 vm_cmdline_get_device);
697 return strlen(buffer) + 1;
700 static const struct kernel_param_ops vm_cmdline_param_ops = {
701 .set = vm_cmdline_set,
702 .get = vm_cmdline_get,
705 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
707 static int vm_unregister_cmdline_device(struct device *dev,
710 platform_device_unregister(to_platform_device(dev));
715 static void vm_unregister_cmdline_devices(void)
717 if (vm_cmdline_parent_registered) {
718 device_for_each_child(&vm_cmdline_parent, NULL,
719 vm_unregister_cmdline_device);
720 device_unregister(&vm_cmdline_parent);
721 vm_cmdline_parent_registered = 0;
727 static void vm_unregister_cmdline_devices(void)
733 /* Platform driver */
735 static struct of_device_id virtio_mmio_match[] = {
736 { .compatible = "virtio,mmio", },
739 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
742 static const struct acpi_device_id virtio_mmio_acpi_match[] = {
746 MODULE_DEVICE_TABLE(acpi, virtio_mmio_acpi_match);
749 static struct platform_driver virtio_mmio_driver = {
750 .probe = virtio_mmio_probe,
751 .remove = virtio_mmio_remove,
753 .name = "virtio-mmio",
754 .of_match_table = virtio_mmio_match,
755 .acpi_match_table = ACPI_PTR(virtio_mmio_acpi_match),
756 #ifdef CONFIG_PM_SLEEP
757 .pm = &virtio_mmio_pm_ops,
762 static int __init virtio_mmio_init(void)
764 return platform_driver_register(&virtio_mmio_driver);
767 static void __exit virtio_mmio_exit(void)
769 platform_driver_unregister(&virtio_mmio_driver);
770 vm_unregister_cmdline_devices();
773 module_init(virtio_mmio_init);
774 module_exit(virtio_mmio_exit);
776 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
777 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
778 MODULE_LICENSE("GPL");