diff options
Diffstat (limited to 'drivers/virtio/virtio_mmio.c')
| -rw-r--r-- | drivers/virtio/virtio_mmio.c | 485 |
1 files changed, 485 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c new file mode 100644 index 00000000..01d6dc25 --- /dev/null +++ b/drivers/virtio/virtio_mmio.c @@ -0,0 +1,485 @@ +/* + * 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"); |