This patch, based on virtio PCI driver, adds support for virtio AMBA device. This should allow environments like qemu to use virtio-based block & network devices.

For example, one can define and register an AMBA device like this (emulation environment must of course provide a correctly mapped "Virtio Block Device Prime Cell"):

struct amba_device virtio_block = { .dev.init_name = "virtio-block", .res = { .start = 0x1c0d0000, .end = 0x1c0d0fff, .flags = IORESOURCE_MEM, }, .irq = { 73, }, };

This should be soon replaced with Device Tree entry supplied by the simulation environment.

Signed-off-by: Pawel Moll pawel.moll@arm.com --- drivers/virtio/Kconfig | 11 + drivers/virtio/Makefile | 1 + drivers/virtio/virtio_amba.c | 443 ++++++++++++++++++++++++++++++++++++++++++ include/linux/virtio_amba.h | 62 ++++++ 4 files changed, 517 insertions(+), 0 deletions(-) create mode 100644 drivers/virtio/virtio_amba.c create mode 100644 include/linux/virtio_amba.h

diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index 57e493b..a8530ab 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -35,4 +35,15 @@ config VIRTIO_BALLOON

If unsure, say M.

+ config VIRTIO_AMBA + tristate "AMBA bus driver for virtio devices (EXPERIMENTAL)" + depends on ARM_AMBA && EXPERIMENTAL + select VIRTIO + select VIRTIO_RING + ---help--- + This drivers provides support for virtio based paravirtual device + drivers over an AMBA bus. + + If unsure, say N. + endmenu diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile index 6738c44..49147cb 100644 --- a/drivers/virtio/Makefile +++ b/drivers/virtio/Makefile @@ -1,4 +1,5 @@ obj-$(CONFIG_VIRTIO) += virtio.o obj-$(CONFIG_VIRTIO_RING) += virtio_ring.o +obj-$(CONFIG_VIRTIO_AMBA) += virtio_amba.o obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o obj-$(CONFIG_VIRTIO_BALLOON) += virtio_balloon.o diff --git a/drivers/virtio/virtio_amba.c b/drivers/virtio/virtio_amba.c new file mode 100644 index 0000000..0cfbaec --- /dev/null +++ b/drivers/virtio/virtio_amba.c @@ -0,0 +1,443 @@ +/* + * Virtio AMBA driver + * + * Copyright 2011, ARM Ltd. + * + * This module allows virtio devices to be used over a virtual AMBA device. + * + * Registers layout: + * + * offset width name description + * ------ ----- ------------- ----------------- + * + * 0x000 32 HostFeatures Features supported by the host + * 0x004 32 GuestFeatures Features activated by the guest + * 0x008 32 QueuePFN PFN for the currently selected queue + * 0x00c 32 QueueNum Queue size for the currently selected queue + * 0x010 32 QueueSel Queue selector + * 0x014 32 QueueNotify Queue notifier + * 0x018 8 InterruptACK Interrupt acknowledge register + * 0x01c 8 Status Device status register + * + * 0x020 + * ... Device-specific configuration space + * 0xfdf + * + * 0xfe0 8 PeriphID0 0x30 + * 0xfe4 8 PeriphID1 0x17 + * 0xfe8 8 PeriphID2 0x04 + * 0xfec 8 PeriphID3 VIRTIO_ID_* (see <linux/virtio_ids.h>) + * 0xff0 8 PCellID0 0x0d + * 0xff4 8 PCellID1 0xf0 + * 0xff8 8 PCellID2 0x05 + * 0xffc 8 PCellID3 0xb1 + * + * 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/module.h> +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/amba/bus.h> +#include <linux/interrupt.h> +#include <linux/virtio.h> +#include <linux/virtio_amba.h> +#include <linux/virtio_config.h> +#include <linux/virtio_ring.h> +#include <linux/highmem.h> +#include <linux/spinlock.h> + + + +#define to_virtio_amba_device(_amba_dev) \ + container_of(_amba_dev, struct virtio_amba_device, vdev) + +struct virtio_amba_device { + struct virtio_device vdev; + struct amba_device *amba_dev; + + void __iomem *base; + + /* a list of queues so we can dispatch IRQs */ + spinlock_t lock; + struct list_head virtqueues; +}; + +struct virtio_amba_vq_info { + /* the actual virtqueue */ + struct virtqueue *vq; + + /* the number of entries in the queue */ + 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 va_get_features(struct virtio_device *vdev) +{ + struct virtio_amba_device *va_dev = to_virtio_amba_device(vdev); + + /* When someone needs more than 32 feature bits, we'll need to + * steal a bit to indicate that the rest are somewhere else. */ + return readl(va_dev->base + VIRTIO_AMBA_HOST_FEATURES); +} + +static void va_finalize_features(struct virtio_device *vdev) +{ + struct virtio_amba_device *va_dev = to_virtio_amba_device(vdev); + + /* Give virtio_ring a chance to accept features. */ + vring_transport_features(vdev); + + /* We only support 32 feature bits. */ + BUILD_BUG_ON(ARRAY_SIZE(vdev->features) != 1); + writel(vdev->features[0], va_dev->base + VIRTIO_AMBA_GUEST_FEATURES); +} + +static void va_get(struct virtio_device *vdev, unsigned offset, + void *buf, unsigned len) +{ + struct virtio_amba_device *va_dev = to_virtio_amba_device(vdev); + u8 *ptr = buf; + int i; + + for (i = 0; i < len; i++) + ptr[i] = readb(va_dev->base + VIRTIO_AMBA_CONFIG + offset + i); +} + +static void va_set(struct virtio_device *vdev, unsigned offset, + const void *buf, unsigned len) +{ + struct virtio_amba_device *va_dev = to_virtio_amba_device(vdev); + const u8 *ptr = buf; + int i; + + for (i = 0; i < len; i++) + writeb(ptr[i], va_dev->base + VIRTIO_AMBA_CONFIG + offset + i); +} + +static u8 va_get_status(struct virtio_device *vdev) +{ + struct virtio_amba_device *va_dev = to_virtio_amba_device(vdev); + + return readb(va_dev->base + VIRTIO_AMBA_STATUS) & 0xff; +} + +static void va_set_status(struct virtio_device *vdev, u8 status) +{ + struct virtio_amba_device *va_dev = to_virtio_amba_device(vdev); + + /* We should never be setting status to 0. */ + BUG_ON(status == 0); + + writeb(status, va_dev->base + VIRTIO_AMBA_STATUS); +} + +static void va_reset(struct virtio_device *vdev) +{ + struct virtio_amba_device *va_dev = to_virtio_amba_device(vdev); + + /* 0 status means a reset. */ + writeb(0, va_dev->base + VIRTIO_AMBA_STATUS); +} + + + +/* Transport interface */ + +/* the notify function used when creating a virt queue */ +static void va_notify(struct virtqueue *vq) +{ + struct virtio_amba_device *va_dev = to_virtio_amba_device(vq->vdev); + struct virtio_amba_vq_info *info = vq->priv; + + /* We write the queue's selector into the notification register to + * signal the other end */ + writel(info->queue_index, va_dev->base + VIRTIO_AMBA_QUEUE_NOTIFY); +} + +/* Notify all virtqueues on an interrupt. */ +static irqreturn_t va_interrupt(int irq, void *opaque) +{ + struct virtio_amba_device *va_dev = opaque; + struct virtio_amba_vq_info *info; + irqreturn_t ret = IRQ_NONE; + unsigned long flags; + + writeb(1, va_dev->base + VIRTIO_AMBA_INTERRUPT_ACK); + + spin_lock_irqsave(&va_dev->lock, flags); + list_for_each_entry(info, &va_dev->virtqueues, node) { + if (vring_interrupt(irq, info->vq) == IRQ_HANDLED) + ret = IRQ_HANDLED; + } + spin_unlock_irqrestore(&va_dev->lock, flags); + + return ret; +} + + + +static void va_del_vq(struct virtqueue *vq) +{ + struct virtio_amba_device *va_dev = to_virtio_amba_device(vq->vdev); + struct virtio_amba_vq_info *info = vq->priv; + unsigned long flags, size; + + spin_lock_irqsave(&va_dev->lock, flags); + list_del(&info->node); + spin_unlock_irqrestore(&va_dev->lock, flags); + + writel(info->queue_index, va_dev->base + VIRTIO_AMBA_QUEUE_SEL); + + vring_del_virtqueue(vq); + + /* Select and deactivate the queue */ + writel(0, va_dev->base + VIRTIO_AMBA_QUEUE_PFN); + + size = PAGE_ALIGN(vring_size(info->num, VIRTIO_AMBA_VRING_ALIGN)); + free_pages_exact(info->queue, size); + kfree(info); +} + +static void va_del_vqs(struct virtio_device *vdev) +{ + struct virtio_amba_device *va_dev = to_virtio_amba_device(vdev); + struct virtqueue *vq, *n; + + list_for_each_entry_safe(vq, n, &vdev->vqs, list) + va_del_vq(vq); + + free_irq(va_dev->amba_dev->irq[0], va_dev); +} + + + +static struct virtqueue *va_setup_vq(struct virtio_device *vdev, unsigned index, + void (*callback)(struct virtqueue *vq), + const char *name) +{ + struct virtio_amba_device *va_dev = to_virtio_amba_device(vdev); + struct virtio_amba_vq_info *info; + struct virtqueue *vq; + unsigned long flags, size; + u16 num; + int err; + + /* Select the queue we're interested in */ + writel(index, va_dev->base + VIRTIO_AMBA_QUEUE_SEL); + + /* Check if queue is either not available or already active. */ + num = readl(va_dev->base + VIRTIO_AMBA_QUEUE_NUM); + if (!num || readl(va_dev->base + VIRTIO_AMBA_QUEUE_PFN)) { + err = -ENOENT; + goto error_available; + } + + /* Allocate and fill out our structure the represents an active + * queue */ + info = kmalloc(sizeof(struct virtio_amba_vq_info), GFP_KERNEL); + if (!info) { + err = -ENOMEM; + goto error_kmalloc; + } + + info->queue_index = index; + info->num = num; + + size = PAGE_ALIGN(vring_size(num, VIRTIO_AMBA_VRING_ALIGN)); + info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO); + if (info->queue == NULL) { + err = -ENOMEM; + goto error_alloc_pages; + } + + /* Activate the queue */ + writel(virt_to_phys(info->queue) >> VIRTIO_AMBA_QUEUE_ADDR_SHIFT, + va_dev->base + VIRTIO_AMBA_QUEUE_PFN); + + /* Create the vring */ + vq = vring_new_virtqueue(info->num, VIRTIO_AMBA_VRING_ALIGN, + vdev, info->queue, va_notify, callback, name); + if (!vq) { + err = -ENOMEM; + goto error_new_virtqueue; + } + + vq->priv = info; + info->vq = vq; + + spin_lock_irqsave(&va_dev->lock, flags); + list_add(&info->node, &va_dev->virtqueues); + spin_unlock_irqrestore(&va_dev->lock, flags); + + return vq; + +error_new_virtqueue: + writel(0, va_dev->base + VIRTIO_AMBA_QUEUE_PFN); + free_pages_exact(info->queue, size); +error_alloc_pages: + kfree(info); +error_kmalloc: +error_available: + return ERR_PTR(err); +} + +static int va_find_vqs(struct virtio_device *vdev, unsigned nvqs, + struct virtqueue *vqs[], + vq_callback_t *callbacks[], + const char *names[]) +{ + struct virtio_amba_device *va_dev = to_virtio_amba_device(vdev); + int i, err; + + err = request_irq(va_dev->amba_dev->irq[0], va_interrupt, + IRQF_SHARED, dev_name(&vdev->dev), va_dev); + if (err) + goto error_request_irq; + + for (i = 0; i < nvqs; ++i) { + vqs[i] = va_setup_vq(vdev, i, callbacks[i], names[i]); + if (IS_ERR(vqs[i])) { + err = PTR_ERR(vqs[i]); + goto error_va_setup_vq; + } + } + + return 0; + +error_va_setup_vq: + va_del_vqs(vdev); +error_request_irq: + return err; +} + + + +static struct virtio_config_ops virtio_amba_config_ops = { + .get = va_get, + .set = va_set, + .get_status = va_get_status, + .set_status = va_set_status, + .reset = va_reset, + .find_vqs = va_find_vqs, + .del_vqs = va_del_vqs, + .get_features = va_get_features, + .finalize_features = va_finalize_features, +}; + + + +/* AMBA device */ + +static int __devinit virtio_amba_probe(struct amba_device *amba_dev, + const struct amba_id *id) +{ + struct virtio_amba_device *va_dev; + int err; + + va_dev = kzalloc(sizeof(struct virtio_amba_device), GFP_KERNEL); + if (va_dev == NULL) { + err = -ENOMEM; + goto error_kzalloc; + } + + va_dev->vdev.dev.parent = &amba_dev->dev; + va_dev->vdev.config = &virtio_amba_config_ops; + va_dev->amba_dev = amba_dev; + INIT_LIST_HEAD(&va_dev->virtqueues); + spin_lock_init(&va_dev->lock); + + err = amba_request_regions(amba_dev, "virtio-amba"); + if (err) + goto error_request_regions; + + va_dev->base = ioremap(amba_dev->res.start, + resource_size(&amba_dev->res)); + if (va_dev->base == NULL) + goto error_ioremap; + + /* We use the "Configuration" field in Prime Cell ID + * as the virtio device id. */ + va_dev->vdev.id.device = amba_config(amba_dev); + + amba_set_drvdata(amba_dev, va_dev); + + err = register_virtio_device(&va_dev->vdev); + if (err) + goto error_register_virtio_device; + + return 0; + +error_register_virtio_device: + iounmap(va_dev->base); +error_ioremap: + amba_release_regions(amba_dev); +error_request_regions: + kfree(va_dev); +error_kzalloc: + return err; +} + +static int __devexit virtio_amba_remove(struct amba_device *amba_dev) +{ + struct virtio_amba_device *va_dev = amba_get_drvdata(amba_dev); + + unregister_virtio_device(&va_dev->vdev); + + iounmap(va_dev->base); + amba_release_regions(amba_dev); + kfree(va_dev); + + return 0; +} + + + +/* AMBA driver */ + +static struct amba_id virtio_amba_ids[] = { + { + .id = 0x00041730, + .mask = 0x000fffff, + }, + { 0, 0 } +}; + +static struct amba_driver virtio_amba_driver = { + .drv.name = "virtio-amba", + .probe = virtio_amba_probe, + .remove = __devexit_p(virtio_amba_remove), + .id_table = virtio_amba_ids, +}; + +static int __init virtio_amba_init(void) +{ + return amba_driver_register(&virtio_amba_driver); +} + +static void __exit virtio_amba_exit(void) +{ + amba_driver_unregister(&virtio_amba_driver); +} + +module_init(virtio_amba_init); +module_exit(virtio_amba_exit); + +MODULE_AUTHOR("Pawel Moll pawel.moll@arm.com"); +MODULE_DESCRIPTION("AMBA bus driver for virtio devices"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/virtio_amba.h b/include/linux/virtio_amba.h new file mode 100644 index 0000000..c754b87 --- /dev/null +++ b/include/linux/virtio_amba.h @@ -0,0 +1,62 @@ +/* + * Virtio AMBA driver + * + * Copyright 2011, ARM Ltd. + * + * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007 + * + * This header is BSD licensed so anyone can use the definitions to implement + * compatible drivers/servers. + */ + +#ifndef _LINUX_VIRTIO_AMBA_H +#define _LINUX_VIRTIO_AMBA_H + +/* Bitmask of the features supported by the host (32-bit register) */ +#define VIRTIO_AMBA_HOST_FEATURES 0x000 + +/* Bitmask of features activated by the guest (32-bit register) */ +#define VIRTIO_AMBA_GUEST_FEATURES 0x004 + +/* PFN for the currently selected queue (32-bit register) */ +#define VIRTIO_AMBA_QUEUE_PFN 0x008 + +/* Queue size for the currently selected queue (32-bit register) */ +#define VIRTIO_AMBA_QUEUE_NUM 0x00c + +/* Queue selector (32-bit register) */ +#define VIRTIO_AMBA_QUEUE_SEL 0x010 + +/* Queue notifier (32-bit register) */ +#define VIRTIO_AMBA_QUEUE_NOTIFY 0x014 + +/* Interrupt acknowledge (8-bit register) */ +#define VIRTIO_AMBA_INTERRUPT_ACK 0x018 + +/* Device status register (8-bit register) */ +#define VIRTIO_AMBA_STATUS 0x01c + +/* The config space is defined by each driver as + * the per-driver configuration space */ +#define VIRTIO_AMBA_CONFIG 0x020 + +/* PrimeCell identification registers (8-bit registers) */ +#define VIRTIO_AMBA_PERIPH_ID0 0xfe0 +#define VIRTIO_AMBA_PERIPH_ID1 0xfe4 +#define VIRTIO_AMBA_PERIPH_ID2 0xfe8 +#define VIRTIO_AMBA_PERIPH_ID3 0xfec +#define VIRTIO_AMBA_PCELL_ID0 0xff0 +#define VIRTIO_AMBA_PCELL_ID1 0xff4 +#define VIRTIO_AMBA_PCELL_ID2 0xff8 +#define VIRTIO_AMBA_PCELL_ID3 0xffc + + +/* How many bits to shift physical queue address written to QUEUE_PFN. + * 12 is historical, and due to 4kb page size. */ +#define VIRTIO_AMBA_QUEUE_ADDR_SHIFT 12 + +/* The alignment to use between consumer and producer parts of vring. + * Page size again. */ +#define VIRTIO_AMBA_VRING_ALIGN 4096 + +#endif