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/highmem.h>
62 #include <linux/interrupt.h>
64 #include <linux/list.h>
65 #include <linux/module.h>
66 #include <linux/platform_device.h>
67 #include <linux/slab.h>
68 #include <linux/spinlock.h>
69 #include <linux/virtio.h>
70 #include <linux/virtio_config.h>
71 #include <linux/virtio_mmio.h>
72 #include <linux/virtio_ring.h>
76 /* The alignment to use between consumer and producer parts of vring.
77 * Currently hardcoded to the page size. */
78 #define VIRTIO_MMIO_VRING_ALIGN PAGE_SIZE
82 #define to_virtio_mmio_device(_plat_dev) \
83 container_of(_plat_dev, struct virtio_mmio_device, vdev)
85 struct virtio_mmio_device {
86 struct virtio_device vdev;
87 struct platform_device *pdev;
90 unsigned long version;
92 /* a list of queues so we can dispatch IRQs */
94 struct list_head virtqueues;
97 struct virtio_mmio_vq_info {
98 /* the actual virtqueue */
101 /* the number of entries in the queue */
104 /* the virtual address of the ring queue */
107 /* the list node for the virtqueues list */
108 struct list_head node;
113 /* Configuration interface */
115 static u64 vm_get_features(struct virtio_device *vdev)
117 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
120 writel(1, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
121 features = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
124 writel(0, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
125 features |= readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
130 static int vm_finalize_features(struct virtio_device *vdev)
132 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
134 /* Give virtio_ring a chance to accept features. */
135 vring_transport_features(vdev);
137 /* Make sure there is are no mixed devices */
138 if (vm_dev->version == 2 &&
139 !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
140 dev_err(&vdev->dev, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n");
144 writel(1, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
145 writel((u32)(vdev->features >> 32),
146 vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
148 writel(0, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
149 writel((u32)vdev->features,
150 vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
155 static void vm_get(struct virtio_device *vdev, unsigned offset,
156 void *buf, unsigned len)
158 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
162 for (i = 0; i < len; i++)
163 ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
166 static void vm_set(struct virtio_device *vdev, unsigned offset,
167 const void *buf, unsigned len)
169 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
173 for (i = 0; i < len; i++)
174 writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
177 static u8 vm_get_status(struct virtio_device *vdev)
179 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
181 return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
184 static void vm_set_status(struct virtio_device *vdev, u8 status)
186 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
188 /* We should never be setting status to 0. */
191 writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
194 static void vm_reset(struct virtio_device *vdev)
196 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
198 /* 0 status means a reset. */
199 writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
204 /* Transport interface */
206 /* the notify function used when creating a virt queue */
207 static bool vm_notify(struct virtqueue *vq)
209 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
211 /* We write the queue's selector into the notification register to
212 * signal the other end */
213 writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
217 /* Notify all virtqueues on an interrupt. */
218 static irqreturn_t vm_interrupt(int irq, void *opaque)
220 struct virtio_mmio_device *vm_dev = opaque;
221 struct virtio_mmio_vq_info *info;
222 unsigned long status;
224 irqreturn_t ret = IRQ_NONE;
226 /* Read and acknowledge interrupts */
227 status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
228 writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
230 if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)) {
231 virtio_config_changed(&vm_dev->vdev);
235 if (likely(status & VIRTIO_MMIO_INT_VRING)) {
236 spin_lock_irqsave(&vm_dev->lock, flags);
237 list_for_each_entry(info, &vm_dev->virtqueues, node)
238 ret |= vring_interrupt(irq, info->vq);
239 spin_unlock_irqrestore(&vm_dev->lock, flags);
247 static void vm_del_vq(struct virtqueue *vq)
249 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
250 struct virtio_mmio_vq_info *info = vq->priv;
251 unsigned long flags, size;
252 unsigned int index = vq->index;
254 spin_lock_irqsave(&vm_dev->lock, flags);
255 list_del(&info->node);
256 spin_unlock_irqrestore(&vm_dev->lock, flags);
258 vring_del_virtqueue(vq);
260 /* Select and deactivate the queue */
261 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
262 if (vm_dev->version == 1) {
263 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
265 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
266 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
269 size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
270 free_pages_exact(info->queue, size);
274 static void vm_del_vqs(struct virtio_device *vdev)
276 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
277 struct virtqueue *vq, *n;
279 list_for_each_entry_safe(vq, n, &vdev->vqs, list)
282 free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
287 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
288 void (*callback)(struct virtqueue *vq),
291 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
292 struct virtio_mmio_vq_info *info;
293 struct virtqueue *vq;
294 unsigned long flags, size;
300 /* Select the queue we're interested in */
301 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
303 /* Queue shouldn't already be set up. */
304 if (readl(vm_dev->base + (vm_dev->version == 1 ?
305 VIRTIO_MMIO_QUEUE_PFN : VIRTIO_MMIO_QUEUE_READY))) {
307 goto error_available;
310 /* Allocate and fill out our active queue description */
311 info = kmalloc(sizeof(*info), GFP_KERNEL);
317 /* Allocate pages for the queue - start with a queue as big as
318 * possible (limited by maximum size allowed by device), drop down
319 * to a minimal size, just big enough to fit descriptor table
320 * and two rings (which makes it "alignment_size * 2")
322 info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
324 /* If the device reports a 0 entry queue, we won't be able to
325 * use it to perform I/O, and vring_new_virtqueue() can't create
326 * empty queues anyway, so don't bother to set up the device.
328 if (info->num == 0) {
330 goto error_alloc_pages;
334 size = PAGE_ALIGN(vring_size(info->num,
335 VIRTIO_MMIO_VRING_ALIGN));
336 /* Did the last iter shrink the queue below minimum size? */
337 if (size < VIRTIO_MMIO_VRING_ALIGN * 2) {
339 goto error_alloc_pages;
342 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
349 /* Create the vring */
350 vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
351 true, info->queue, vm_notify, callback, name);
354 goto error_new_virtqueue;
357 /* Activate the queue */
358 writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
359 if (vm_dev->version == 1) {
360 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
361 writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
362 vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
366 addr = virt_to_phys(info->queue);
367 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_LOW);
368 writel((u32)(addr >> 32),
369 vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_HIGH);
371 addr = virt_to_phys(virtqueue_get_avail(vq));
372 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_LOW);
373 writel((u32)(addr >> 32),
374 vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_HIGH);
376 addr = virt_to_phys(virtqueue_get_used(vq));
377 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_USED_LOW);
378 writel((u32)(addr >> 32),
379 vm_dev->base + VIRTIO_MMIO_QUEUE_USED_HIGH);
381 writel(1, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
387 spin_lock_irqsave(&vm_dev->lock, flags);
388 list_add(&info->node, &vm_dev->virtqueues);
389 spin_unlock_irqrestore(&vm_dev->lock, flags);
394 if (vm_dev->version == 1) {
395 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
397 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
398 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
400 free_pages_exact(info->queue, size);
408 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
409 struct virtqueue *vqs[],
410 vq_callback_t *callbacks[],
413 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
414 unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
417 err = request_irq(irq, vm_interrupt, IRQF_SHARED,
418 dev_name(&vdev->dev), vm_dev);
422 for (i = 0; i < nvqs; ++i) {
423 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
424 if (IS_ERR(vqs[i])) {
426 return PTR_ERR(vqs[i]);
433 static const char *vm_bus_name(struct virtio_device *vdev)
435 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
437 return vm_dev->pdev->name;
440 static const struct virtio_config_ops virtio_mmio_config_ops = {
443 .get_status = vm_get_status,
444 .set_status = vm_set_status,
446 .find_vqs = vm_find_vqs,
447 .del_vqs = vm_del_vqs,
448 .get_features = vm_get_features,
449 .finalize_features = vm_finalize_features,
450 .bus_name = vm_bus_name,
455 /* Platform device */
457 static int virtio_mmio_probe(struct platform_device *pdev)
459 struct virtio_mmio_device *vm_dev;
460 struct resource *mem;
463 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
467 if (!devm_request_mem_region(&pdev->dev, mem->start,
468 resource_size(mem), pdev->name))
471 vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
475 vm_dev->vdev.dev.parent = &pdev->dev;
476 vm_dev->vdev.config = &virtio_mmio_config_ops;
478 INIT_LIST_HEAD(&vm_dev->virtqueues);
479 spin_lock_init(&vm_dev->lock);
481 vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
482 if (vm_dev->base == NULL)
485 /* Check magic value */
486 magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
487 if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
488 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
492 /* Check device version */
493 vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
494 if (vm_dev->version < 1 || vm_dev->version > 2) {
495 dev_err(&pdev->dev, "Version %ld not supported!\n",
500 vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
501 if (vm_dev->vdev.id.device == 0) {
503 * virtio-mmio device with an ID 0 is a (dummy) placeholder
504 * with no function. End probing now with no error reported.
508 vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
510 /* Reject legacy-only IDs for version 2 devices */
511 if (vm_dev->version == 2 &&
512 virtio_device_is_legacy_only(vm_dev->vdev.id)) {
513 dev_err(&pdev->dev, "Version 2 not supported for devices %u!\n",
514 vm_dev->vdev.id.device);
518 if (vm_dev->version == 1)
519 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
521 platform_set_drvdata(pdev, vm_dev);
523 return register_virtio_device(&vm_dev->vdev);
526 static int virtio_mmio_remove(struct platform_device *pdev)
528 struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
530 unregister_virtio_device(&vm_dev->vdev);
537 /* Devices list parameter */
539 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
541 static struct device vm_cmdline_parent = {
542 .init_name = "virtio-mmio-cmdline",
545 static int vm_cmdline_parent_registered;
546 static int vm_cmdline_id;
548 static int vm_cmdline_set(const char *device,
549 const struct kernel_param *kp)
552 struct resource resources[2] = {};
554 long long int base, size;
556 int processed, consumed = 0;
557 struct platform_device *pdev;
559 /* Consume "size" part of the command line parameter */
560 size = memparse(device, &str);
562 /* Get "@<base>:<irq>[:<id>]" chunks */
563 processed = sscanf(str, "@%lli:%u%n:%d%n",
564 &base, &irq, &consumed,
565 &vm_cmdline_id, &consumed);
568 * sscanf() must processes at least 2 chunks; also there
569 * must be no extra characters after the last chunk, so
570 * str[consumed] must be '\0'
572 if (processed < 2 || str[consumed])
575 resources[0].flags = IORESOURCE_MEM;
576 resources[0].start = base;
577 resources[0].end = base + size - 1;
579 resources[1].flags = IORESOURCE_IRQ;
580 resources[1].start = resources[1].end = irq;
582 if (!vm_cmdline_parent_registered) {
583 err = device_register(&vm_cmdline_parent);
585 pr_err("Failed to register parent device!\n");
588 vm_cmdline_parent_registered = 1;
591 pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
593 (unsigned long long)resources[0].start,
594 (unsigned long long)resources[0].end,
595 (int)resources[1].start);
597 pdev = platform_device_register_resndata(&vm_cmdline_parent,
598 "virtio-mmio", vm_cmdline_id++,
599 resources, ARRAY_SIZE(resources), NULL, 0);
601 return PTR_ERR(pdev);
606 static int vm_cmdline_get_device(struct device *dev, void *data)
609 unsigned int len = strlen(buffer);
610 struct platform_device *pdev = to_platform_device(dev);
612 snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
613 pdev->resource[0].end - pdev->resource[0].start + 1ULL,
614 (unsigned long long)pdev->resource[0].start,
615 (unsigned long long)pdev->resource[1].start,
620 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
623 device_for_each_child(&vm_cmdline_parent, buffer,
624 vm_cmdline_get_device);
625 return strlen(buffer) + 1;
628 static struct kernel_param_ops vm_cmdline_param_ops = {
629 .set = vm_cmdline_set,
630 .get = vm_cmdline_get,
633 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
635 static int vm_unregister_cmdline_device(struct device *dev,
638 platform_device_unregister(to_platform_device(dev));
643 static void vm_unregister_cmdline_devices(void)
645 if (vm_cmdline_parent_registered) {
646 device_for_each_child(&vm_cmdline_parent, NULL,
647 vm_unregister_cmdline_device);
648 device_unregister(&vm_cmdline_parent);
649 vm_cmdline_parent_registered = 0;
655 static void vm_unregister_cmdline_devices(void)
661 /* Platform driver */
663 static struct of_device_id virtio_mmio_match[] = {
664 { .compatible = "virtio,mmio", },
667 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
669 static struct platform_driver virtio_mmio_driver = {
670 .probe = virtio_mmio_probe,
671 .remove = virtio_mmio_remove,
673 .name = "virtio-mmio",
674 .of_match_table = virtio_mmio_match,
678 static int __init virtio_mmio_init(void)
680 return platform_driver_register(&virtio_mmio_driver);
683 static void __exit virtio_mmio_exit(void)
685 platform_driver_unregister(&virtio_mmio_driver);
686 vm_unregister_cmdline_devices();
689 module_init(virtio_mmio_init);
690 module_exit(virtio_mmio_exit);
692 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
693 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
694 MODULE_LICENSE("GPL");