/*
* Virtio memory mapped device driver
*
* Copyright 2011, ARM Ltd.
*
* This module allows virtio devices to be used over a virtual, memory mapped
* platform device.
*
* Registers layout (all 32-bit wide):
*
* offset d. name description
* ------ -- ---------------- -----------------
*
* 0x000 R MagicValue Magic value "virt"
* 0x004 R Version Device version (current max. 1)
* 0x008 R DeviceID Virtio device ID
* 0x00c R VendorID Virtio vendor ID
*
* 0x010 R HostFeatures Features supported by the host
* 0x014 W HostFeaturesSel Set of host features to access via HostFeatures
*
* 0x020 W GuestFeatures Features activated by the guest
* 0x024 W GuestFeaturesSel Set of activated features to set via GuestFeatures
* 0x028 W GuestPageSize Size of guest's memory page in bytes
*
* 0x030 W QueueSel Queue selector
* 0x034 R QueueNumMax Maximum size of the currently selected queue
* 0x038 W QueueNum Queue size for the currently selected queue
* 0x03c W QueueAlign Used Ring alignment for the current queue
* 0x040 RW QueuePFN PFN for the currently selected queue
*
* 0x050 W QueueNotify Queue notifier
* 0x060 R InterruptStatus Interrupt status register
* 0x060 W InterruptACK Interrupt acknowledge register
* 0x070 RW Status Device status register
*
* 0x100+ RW Device-specific configuration space
*
* Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include <linux/highmem.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/virtio.h>
#include <linux/virtio_config.h>
#include <linux/virtio_mmio.h>
#include <linux/virtio_ring.h>
/* The alignment to use between consumer and producer parts of vring.
* Currently hardcoded to the page size. */
#define VIRTIO_MMIO_VRING_ALIGN PAGE_SIZE
#define to_virtio_mmio_device(_plat_dev) \
container_of(_plat_dev, struct virtio_mmio_device, vdev)
struct virtio_mmio_device {
struct virtio_device vdev;
struct platform_device *pdev;
void __iomem *base;
unsigned long version;
/* a list of queues so we can dispatch IRQs */
spinlock_t lock;
struct list_head virtqueues;
};
struct virtio_mmio_vq_info {
/* the actual virtqueue */
struct virtqueue *vq;
/* the number of entries in the queue */
unsigned int num;
/* the index of the queue */
int queue_index;
/* the virtual address of the ring queue */
void *queue;
/* the list node for the virtqueues list */
struct list_head node;
};
/* Configuration interface */
static u32 vm_get_features(struct virtio_device *vdev)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
/* TODO: Features > 32 bits */
writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL);
return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
}
static void vm_finalize_features(struct virtio_device *vdev)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
int i;
/* Give virtio_ring a chance to accept features. */
vring_transport_features(vdev);
for (i = 0; i < ARRAY_SIZE(vdev->features); i++) {
writel(i, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
writel(vdev->features[i],
vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
}
}
static void vm_get(struct virtio_device *vdev, unsigned offset,
void *buf, unsigned len)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
u8 *ptr = buf;
int i;
for (i = 0; i < len; i++)
ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
}
static void vm_set(struct virtio_device *vdev, unsigned offset,
const void *buf, unsigned len)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
const u8 *ptr = buf;
int i;
for (i = 0; i < len; i++)
writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
}
static u8 vm_get_status(struct virtio_device *vdev)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
}
static void vm_set_status(struct virtio_device *vdev, u8 status)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
/* We should never be setting status to 0. */
BUG_ON(status == 0);
writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
}
static void vm_reset(struct virtio_device *vdev)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
/* 0 status means a reset. */
writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
}
/* Transport interface */
/* the notify function used when creating a virt queue */
static void vm_notify(struct virtqueue *vq)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
struct virtio_mmio_vq_info *info = vq->priv;
/* We write the queue's selector into the notification register to
* signal the other end */
writel(info->queue_index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
}
/* Notify all virtqueues on an interrupt. */
static irqreturn_t vm_interrupt(int irq, void *opaque)
{
struct virtio_mmio_device *vm_dev = opaque;
struct virtio_mmio_vq_info *info;
struct virtio_driver *vdrv = container_of(vm_dev->vdev.dev.driver,
struct virtio_driver, driver);
unsigned long status;
unsigned long flags;
irqreturn_t ret = IRQ_NONE;
/* Read and acknowledge interrupts */
status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)
&& vdrv && vdrv->config_changed) {
vdrv->config_changed(&vm_dev->vdev);
ret = IRQ_HANDLED;
}
if (likely(status & VIRTIO_MMIO_INT_VRING)) {
spin_lock_irqsave(&vm_dev->lock, flags);
list_for_each_entry(info, &vm_dev->virtqueues, node)
ret |= vring_interrupt(irq, info->vq);
spin_unlock_irqrestore(&vm_dev->lock, flags);
}
return ret;
}
static void vm_del_vq(struct virtqueue *vq)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
struct virtio_mmio_vq_info *info = vq->priv;
unsigned long flags, size;
spin_lock_irqsave(&vm_dev->lock, flags);
list_del(&info->node);
spin_unlock_irqrestore(&vm_dev->lock, flags);
vring_del_virtqueue(vq);
/* Select and deactivate the queue */
writel(info->queue_index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
free_pages_exact(info->queue, size);
kfree(info);
}
static void vm_del_vqs(struct virtio_device *vdev)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
struct virtqueue *vq, *n;
list_for_each_entry_safe(vq, n, &vdev->vqs, list)
vm_del_vq(vq);
free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
}
static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
void (*callback)(struct virtqueue *vq),
const char *name)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
struct virtio_mmio_vq_info *info;
struct virtqueue *vq;
unsigned long flags, size;
int err;
/* Select the queue we're interested in */
writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
/* Queue shouldn't already be set up. */
if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) {
err = -ENOENT;
goto error_available;
}
/* Allocate and fill out our active queue description */
info = kmalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
err = -ENOMEM;
goto error_kmalloc;
}
info->queue_index = index;
/* Allocate pages for the queue - start with a queue as big as
* possible (limited by maximum size allowed by device), drop down
* to a minimal size, just big enough to fit descriptor table
* and two rings (which makes it "alignment_size * 2")
*/
info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
while (1) {
size = PAGE_ALIGN(vring_size(info->num,
VIRTIO_MMIO_VRING_ALIGN));
/* Already smallest possible allocation? */
if (size <= VIRTIO_MMIO_VRING_ALIGN * 2) {
err = -ENOMEM;
goto error_alloc_pages;
}
info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
if (info->queue)
break;
info->num /= 2;
}
/* Activate the queue */
writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
writel(VIRTIO_MMIO_VRING_ALIGN,
vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
/* Create the vring */
vq = vring_new_virtqueue(info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
true, info->queue, vm_notify, callback, name);
if (!vq) {
err = -ENOMEM;
goto error_new_virtqueue;
}
vq->priv = info;
info->vq = vq;
spin_lock_irqsave(&vm_dev->lock, flags);
list_add(&info->node, &vm_dev->virtqueues);
spin_unlock_irqrestore(&vm_dev->lock, flags);
return vq;
error_new_virtqueue:
writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
free_pages_exact(info->queue, size);
error_alloc_pages:
kfree(info);
error_kmalloc:
error_available:
return ERR_PTR(err);
}
static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
struct virtqueue *vqs[],
vq_callback_t *callbacks[],
const char *names[])
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
int i, err;
err = request_irq(irq, vm_interrupt, IRQF_SHARED,
dev_name(&vdev->dev), vm_dev);
if (err)
return err;
for (i = 0; i < nvqs; ++i) {
vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
if (IS_ERR(vqs[i])) {
vm_del_vqs(vdev);
return PTR_ERR(vqs[i]);
}
}
return 0;
}
static const char *vm_bus_name(struct virtio_device *vdev)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
return vm_dev->pdev->name;
}
static struct virtio_config_ops virtio_mmio_config_ops = {
.get = vm_get,
.set = vm_set,
.get_status = vm_get_status,
.set_status = vm_set_status,
.reset = vm_reset,
.find_vqs = vm_find_vqs,
.del_vqs = vm_del_vqs,
.get_features = vm_get_features,
.finalize_features = vm_finalize_features,
.bus_name = vm_bus_name,
};
/* Platform device */
static int __devinit virtio_mmio_probe(struct platform_device *pdev)
{
struct virtio_mmio_device *vm_dev;
struct resource *mem;
unsigned long magic;
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem)
return -EINVAL;
if (!devm_request_mem_region(&pdev->dev, mem->start,
resource_size(mem), pdev->name))
return -EBUSY;
vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
if (!vm_dev)
return -ENOMEM;
vm_dev->vdev.dev.parent = &pdev->dev;
vm_dev->vdev.config = &virtio_mmio_config_ops;
vm_dev->pdev = pdev;
INIT_LIST_HEAD(&vm_dev->virtqueues);
spin_lock_init(&vm_dev->lock);
vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
if (vm_dev->base == NULL)
return -EFAULT;
/* Check magic value */
magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
if (memcmp(&magic, "virt", 4) != 0) {
dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
return -ENODEV;
}
/* Check device version */
vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
if (vm_dev->version != 1) {
dev_err(&pdev->dev, "Version %ld not supported!\n",
vm_dev->version);
return -ENXIO;
}
vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
platform_set_drvdata(pdev, vm_dev);
return register_virtio_device(&vm_dev->vdev);
}
static int __devexit virtio_mmio_remove(struct platform_device *pdev)
{
struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
unregister_virtio_device(&vm_dev->vdev);
return 0;
}
/* Platform driver */
static struct of_device_id virtio_mmio_match[] = {
{ .compatible = "virtio,mmio", },
{},
};
MODULE_DEVICE_TABLE(of, virtio_mmio_match);
static struct platform_driver virtio_mmio_driver = {
.probe = virtio_mmio_probe,
.remove = __devexit_p(virtio_mmio_remove),
.driver = {
.name = "virtio-mmio",
.owner = THIS_MODULE,
.of_match_table = virtio_mmio_match,
},
};
static int __init virtio_mmio_init(void)
{
return platform_driver_register(&virtio_mmio_driver);
}
static void __exit virtio_mmio_exit(void)
{
platform_driver_unregister(&virtio_mmio_driver);
}
module_init(virtio_mmio_init);
module_exit(virtio_mmio_exit);
MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
MODULE_LICENSE("GPL");
