2 * Virtio memory mapped device driver
4 * Copyright 2011, 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 * Registers layout (all 32-bit wide):
55 * offset d. name description
56 * ------ -- ---------------- -----------------
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
63 * 0x010 R HostFeatures Features supported by the host
64 * 0x014 W HostFeaturesSel Set of host features to access via HostFeatures
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
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
76 * 0x050 W QueueNotify Queue notifier
77 * 0x060 R InterruptStatus Interrupt status register
78 * 0x060 W InterruptACK Interrupt acknowledge register
79 * 0x070 RW Status Device status register
81 * 0x100+ RW Device-specific configuration space
83 * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
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.
89 #define pr_fmt(fmt) "virtio-mmio: " fmt
91 #include <linux/highmem.h>
92 #include <linux/interrupt.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>
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
112 #define to_virtio_mmio_device(_plat_dev) \
113 container_of(_plat_dev, struct virtio_mmio_device, vdev)
115 struct virtio_mmio_device {
116 struct virtio_device vdev;
117 struct platform_device *pdev;
120 unsigned long version;
122 /* a list of queues so we can dispatch IRQs */
124 struct list_head virtqueues;
127 struct virtio_mmio_vq_info {
128 /* the actual virtqueue */
129 struct virtqueue *vq;
131 /* the number of entries in the queue */
134 /* the virtual address of the ring queue */
137 /* the list node for the virtqueues list */
138 struct list_head node;
143 /* Configuration interface */
145 static u32 vm_get_features(struct virtio_device *vdev)
147 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
149 /* TODO: Features > 32 bits */
150 writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL);
152 return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
155 static void vm_finalize_features(struct virtio_device *vdev)
157 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
160 /* Give virtio_ring a chance to accept features. */
161 vring_transport_features(vdev);
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);
170 static void vm_get(struct virtio_device *vdev, unsigned offset,
171 void *buf, unsigned len)
173 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
177 for (i = 0; i < len; i++)
178 ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
181 static void vm_set(struct virtio_device *vdev, unsigned offset,
182 const void *buf, unsigned len)
184 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
188 for (i = 0; i < len; i++)
189 writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
192 static u8 vm_get_status(struct virtio_device *vdev)
194 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
196 return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
199 static void vm_set_status(struct virtio_device *vdev, u8 status)
201 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
203 /* We should never be setting status to 0. */
206 writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
209 static void vm_reset(struct virtio_device *vdev)
211 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
213 /* 0 status means a reset. */
214 writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
219 /* Transport interface */
221 /* the notify function used when creating a virt queue */
222 static void vm_notify(struct virtqueue *vq)
224 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
226 /* We write the queue's selector into the notification register to
227 * signal the other end */
228 writel(virtqueue_get_queue_index(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
231 /* Notify all virtqueues on an interrupt. */
232 static irqreturn_t vm_interrupt(int irq, void *opaque)
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;
240 irqreturn_t ret = IRQ_NONE;
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);
246 if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)
247 && vdrv && vdrv->config_changed) {
248 vdrv->config_changed(&vm_dev->vdev);
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);
264 static void vm_del_vq(struct virtqueue *vq)
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 = virtqueue_get_queue_index(vq);
271 spin_lock_irqsave(&vm_dev->lock, flags);
272 list_del(&info->node);
273 spin_unlock_irqrestore(&vm_dev->lock, flags);
275 vring_del_virtqueue(vq);
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);
281 size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
282 free_pages_exact(info->queue, size);
286 static void vm_del_vqs(struct virtio_device *vdev)
288 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
289 struct virtqueue *vq, *n;
291 list_for_each_entry_safe(vq, n, &vdev->vqs, list)
294 free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
299 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
300 void (*callback)(struct virtqueue *vq),
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;
309 /* Select the queue we're interested in */
310 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
312 /* Queue shouldn't already be set up. */
313 if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) {
315 goto error_available;
318 /* Allocate and fill out our active queue description */
319 info = kmalloc(sizeof(*info), GFP_KERNEL);
325 /* Allocate pages for the queue - start with a queue as big as
326 * possible (limited by maximum size allowed by device), drop down
327 * to a minimal size, just big enough to fit descriptor table
328 * and two rings (which makes it "alignment_size * 2")
330 info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
332 size = PAGE_ALIGN(vring_size(info->num,
333 VIRTIO_MMIO_VRING_ALIGN));
334 /* Already smallest possible allocation? */
335 if (size <= VIRTIO_MMIO_VRING_ALIGN * 2) {
337 goto error_alloc_pages;
340 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
347 /* Activate the queue */
348 writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
349 writel(VIRTIO_MMIO_VRING_ALIGN,
350 vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
351 writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
352 vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
354 /* Create the vring */
355 vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
356 true, info->queue, vm_notify, callback, name);
359 goto error_new_virtqueue;
365 spin_lock_irqsave(&vm_dev->lock, flags);
366 list_add(&info->node, &vm_dev->virtqueues);
367 spin_unlock_irqrestore(&vm_dev->lock, flags);
372 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
373 free_pages_exact(info->queue, size);
381 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
382 struct virtqueue *vqs[],
383 vq_callback_t *callbacks[],
386 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
387 unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
390 err = request_irq(irq, vm_interrupt, IRQF_SHARED,
391 dev_name(&vdev->dev), vm_dev);
395 for (i = 0; i < nvqs; ++i) {
396 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
397 if (IS_ERR(vqs[i])) {
399 return PTR_ERR(vqs[i]);
406 static const char *vm_bus_name(struct virtio_device *vdev)
408 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
410 return vm_dev->pdev->name;
413 static struct virtio_config_ops virtio_mmio_config_ops = {
416 .get_status = vm_get_status,
417 .set_status = vm_set_status,
419 .find_vqs = vm_find_vqs,
420 .del_vqs = vm_del_vqs,
421 .get_features = vm_get_features,
422 .finalize_features = vm_finalize_features,
423 .bus_name = vm_bus_name,
428 /* Platform device */
430 static int __devinit virtio_mmio_probe(struct platform_device *pdev)
432 struct virtio_mmio_device *vm_dev;
433 struct resource *mem;
436 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
440 if (!devm_request_mem_region(&pdev->dev, mem->start,
441 resource_size(mem), pdev->name))
444 vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
448 vm_dev->vdev.dev.parent = &pdev->dev;
449 vm_dev->vdev.config = &virtio_mmio_config_ops;
451 INIT_LIST_HEAD(&vm_dev->virtqueues);
452 spin_lock_init(&vm_dev->lock);
454 vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
455 if (vm_dev->base == NULL)
458 /* Check magic value */
459 magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
460 if (memcmp(&magic, "virt", 4) != 0) {
461 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
465 /* Check device version */
466 vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
467 if (vm_dev->version != 1) {
468 dev_err(&pdev->dev, "Version %ld not supported!\n",
473 vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
474 vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
476 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
478 platform_set_drvdata(pdev, vm_dev);
480 return register_virtio_device(&vm_dev->vdev);
483 static int __devexit virtio_mmio_remove(struct platform_device *pdev)
485 struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
487 unregister_virtio_device(&vm_dev->vdev);
494 /* Devices list parameter */
496 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
498 static struct device vm_cmdline_parent = {
499 .init_name = "virtio-mmio-cmdline",
502 static int vm_cmdline_parent_registered;
503 static int vm_cmdline_id;
505 static int vm_cmdline_set(const char *device,
506 const struct kernel_param *kp)
509 struct resource resources[2] = {};
512 int processed, consumed = 0;
513 struct platform_device *pdev;
515 resources[0].flags = IORESOURCE_MEM;
516 resources[1].flags = IORESOURCE_IRQ;
518 resources[0].end = memparse(device, &str) - 1;
520 processed = sscanf(str, "@%lli:%u%n:%d%n",
521 &base, &resources[1].start, &consumed,
522 &vm_cmdline_id, &consumed);
524 if (processed < 2 || processed > 3 || str[consumed])
527 resources[0].start = base;
528 resources[0].end += base;
529 resources[1].end = resources[1].start;
531 if (!vm_cmdline_parent_registered) {
532 err = device_register(&vm_cmdline_parent);
534 pr_err("Failed to register parent device!\n");
537 vm_cmdline_parent_registered = 1;
540 pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
542 (unsigned long long)resources[0].start,
543 (unsigned long long)resources[0].end,
544 (int)resources[1].start);
546 pdev = platform_device_register_resndata(&vm_cmdline_parent,
547 "virtio-mmio", vm_cmdline_id++,
548 resources, ARRAY_SIZE(resources), NULL, 0);
550 return PTR_ERR(pdev);
555 static int vm_cmdline_get_device(struct device *dev, void *data)
558 unsigned int len = strlen(buffer);
559 struct platform_device *pdev = to_platform_device(dev);
561 snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
562 pdev->resource[0].end - pdev->resource[0].start + 1ULL,
563 (unsigned long long)pdev->resource[0].start,
564 (unsigned long long)pdev->resource[1].start,
569 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
572 device_for_each_child(&vm_cmdline_parent, buffer,
573 vm_cmdline_get_device);
574 return strlen(buffer) + 1;
577 static struct kernel_param_ops vm_cmdline_param_ops = {
578 .set = vm_cmdline_set,
579 .get = vm_cmdline_get,
582 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
584 static int vm_unregister_cmdline_device(struct device *dev,
587 platform_device_unregister(to_platform_device(dev));
592 static void vm_unregister_cmdline_devices(void)
594 if (vm_cmdline_parent_registered) {
595 device_for_each_child(&vm_cmdline_parent, NULL,
596 vm_unregister_cmdline_device);
597 device_unregister(&vm_cmdline_parent);
598 vm_cmdline_parent_registered = 0;
604 static void vm_unregister_cmdline_devices(void)
610 /* Platform driver */
612 static struct of_device_id virtio_mmio_match[] = {
613 { .compatible = "virtio,mmio", },
616 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
618 static struct platform_driver virtio_mmio_driver = {
619 .probe = virtio_mmio_probe,
620 .remove = __devexit_p(virtio_mmio_remove),
622 .name = "virtio-mmio",
623 .owner = THIS_MODULE,
624 .of_match_table = virtio_mmio_match,
628 static int __init virtio_mmio_init(void)
630 return platform_driver_register(&virtio_mmio_driver);
633 static void __exit virtio_mmio_exit(void)
635 platform_driver_unregister(&virtio_mmio_driver);
636 vm_unregister_cmdline_devices();
639 module_init(virtio_mmio_init);
640 module_exit(virtio_mmio_exit);
642 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
643 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
644 MODULE_LICENSE("GPL");