--- /dev/null
+/* 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
+ *
+ * Adopted for Seabios: Gleb Natapov <gleb@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPLv3
+ * See the COPYING file in the top-level directory.
+ *
+ *
+ */
+
+#include "virtio-ring.h"
+#include "virtio-pci.h"
+#include "biosvar.h" // GET_GLOBAL
+#include "util.h" // dprintf
+
+#define BUG() do { \
+ dprintf(1, "BUG: failure at %s:%d/%s()!\n", \
+ __FILE__, __LINE__, __func__); \
+ while(1); \
+ } while (0)
+#define BUG_ON(condition) do { if (condition) BUG(); } while (0)
+
+/*
+ * vring_more_used
+ *
+ * is there some used buffers ?
+ *
+ */
+
+int vring_more_used(struct vring_virtqueue *vq)
+{
+ struct vring_used *used = GET_FLATPTR(vq->vring.used);
+ int more = GET_FLATPTR(vq->last_used_idx) != GET_FLATPTR(used->idx);
+ /* Make sure ring reads are done after idx read above. */
+ smp_rmb();
+ return more;
+}
+
+/*
+ * 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;
+ struct vring_desc *desc = GET_FLATPTR(vr->desc);
+ unsigned int i;
+
+ /* find end of given descriptor */
+
+ i = head;
+ while (GET_FLATPTR(desc[i].flags) & VRING_DESC_F_NEXT)
+ i = GET_FLATPTR(desc[i].next);
+
+ /* link it with free list and point to it */
+
+ SET_FLATPTR(desc[i].next, GET_FLATPTR(vq->free_head));
+ SET_FLATPTR(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;
+ struct vring_used *used = GET_FLATPTR(vq->vring.used);
+ u32 id;
+ int ret;
+
+// BUG_ON(!vring_more_used(vq));
+
+ elem = &used->ring[GET_FLATPTR(vq->last_used_idx) % GET_FLATPTR(vr->num)];
+ id = GET_FLATPTR(elem->id);
+ if (len != NULL)
+ *len = GET_FLATPTR(elem->len);
+
+ ret = GET_FLATPTR(vq->vdata[id]);
+
+ vring_detach(vq, id);
+
+ SET_FLATPTR(vq->last_used_idx, GET_FLATPTR(vq->last_used_idx) + 1);
+
+ 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, av, head, prev;
+ struct vring_desc *desc = GET_FLATPTR(vr->desc);
+ struct vring_avail *avail = GET_FLATPTR(vr->avail);
+
+ BUG_ON(out + in == 0);
+
+ prev = 0;
+ head = GET_FLATPTR(vq->free_head);
+ for (i = head; out; i = GET_FLATPTR(desc[i].next), out--) {
+ SET_FLATPTR(desc[i].flags, VRING_DESC_F_NEXT);
+ SET_FLATPTR(desc[i].addr, (u64)virt_to_phys(list->addr));
+ SET_FLATPTR(desc[i].len, list->length);
+ prev = i;
+ list++;
+ }
+ for ( ; in; i = GET_FLATPTR(desc[i].next), in--) {
+ SET_FLATPTR(desc[i].flags, VRING_DESC_F_NEXT|VRING_DESC_F_WRITE);
+ SET_FLATPTR(desc[i].addr, (u64)virt_to_phys(list->addr));
+ SET_FLATPTR(desc[i].len, list->length);
+ prev = i;
+ list++;
+ }
+ SET_FLATPTR(desc[prev].flags,
+ GET_FLATPTR(desc[prev].flags) & ~VRING_DESC_F_NEXT);
+
+ SET_FLATPTR(vq->free_head, i);
+
+ SET_FLATPTR(vq->vdata[head], index);
+
+ av = (GET_FLATPTR(avail->idx) + num_added) % GET_FLATPTR(vr->num);
+ SET_FLATPTR(avail->ring[av], head);
+}
+
+void vring_kick(unsigned int ioaddr, struct vring_virtqueue *vq, int num_added)
+{
+ struct vring *vr = &vq->vring;
+ struct vring_avail *avail = GET_FLATPTR(vr->avail);
+
+ /* Make sure idx update is done after ring write. */
+ smp_wmb();
+ SET_FLATPTR(avail->idx, GET_FLATPTR(avail->idx) + num_added);
+
+ vp_notify(ioaddr, GET_FLATPTR(vq->queue_index));
+}
