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/* virtio-pci.c - virtio ring management
*
* (c) Copyright 2008 Bull S.A.S.
*
* Author: Laurent Vivier <Laurent.Vivier@bull.net>
*
* some parts from Linux Virtio Ring
*
* Copyright Rusty Russell IBM Corporation 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 "etherboot.h"
#include "gpxe/io.h"
#include "gpxe/virtio-ring.h"
#include "gpxe/virtio-pci.h"
#define BUG() do { \
printf("BUG: failure at %s:%d/%s()!\n", \
__FILE__, __LINE__, __FUNCTION__); \
while(1); \
} while (0)
#define BUG_ON(condition) do { if (condition) BUG(); } while (0)
/*
* vring_free
*
* put at the begin of the free list the current desc[head]
*/
void vring_detach(struct vring_virtqueue *vq, unsigned int head)
{
struct vring *vr = &vq->vring;
unsigned int i;
/* find end of given descriptor */
i = head;
while (vr->desc[i].flags & VRING_DESC_F_NEXT)
i = vr->desc[i].next;
/* link it with free list and point to it */
vr->desc[i].next = vq->free_head;
wmb();
vq->free_head = head;
}
/*
* vring_get_buf
*
* get a buffer from the used list
*
*/
int vring_get_buf(struct vring_virtqueue *vq, unsigned int *len)
{
struct vring *vr = &vq->vring;
struct vring_used_elem *elem;
u32 id;
int ret;
BUG_ON(!vring_more_used(vq));
elem = &vr->used->ring[vq->last_used_idx % vr->num];
wmb();
id = elem->id;
if (len != NULL)
*len = elem->len;
ret = vq->vdata[id];
vring_detach(vq, id);
vq->last_used_idx++;
return ret;
}
void vring_add_buf(struct vring_virtqueue *vq,
struct vring_list list[],
unsigned int out, unsigned int in,
int index, int num_added)
{
struct vring *vr = &vq->vring;
int i, avail, head, prev;
BUG_ON(out + in == 0);
prev = 0;
head = vq->free_head;
for (i = head; out; i = vr->desc[i].next, out--) {
vr->desc[i].flags = VRING_DESC_F_NEXT;
vr->desc[i].addr = (u64)virt_to_phys(list->addr);
vr->desc[i].len = list->length;
prev = i;
list++;
}
for ( ; in; i = vr->desc[i].next, in--) {
vr->desc[i].flags = VRING_DESC_F_NEXT|VRING_DESC_F_WRITE;
vr->desc[i].addr = (u64)virt_to_phys(list->addr);
vr->desc[i].len = list->length;
prev = i;
list++;
}
vr->desc[prev].flags &= ~VRING_DESC_F_NEXT;
vq->free_head = i;
vq->vdata[head] = index;
avail = (vr->avail->idx + num_added) % vr->num;
vr->avail->ring[avail] = head;
wmb();
}
void vring_kick(unsigned int ioaddr, struct vring_virtqueue *vq, int num_added)
{
struct vring *vr = &vq->vring;
wmb();
vr->avail->idx += num_added;
mb();
if (!(vr->used->flags & VRING_USED_F_NO_NOTIFY))
vp_notify(ioaddr, vq->queue_index);
}
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