Imported Upstream version 16.04

Change-Id: I77eadcd8538a9122e4773cbe55b24033dc451757
Signed-off-by: C.J. Collier <cjcollier@linuxfoundation.org>

1 files changed, 163 insertions, 0 deletions

diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h
new file mode 100644
index 00000000..447760a8
--- /dev/null
+++ b/drivers/net/virtio/virtio_ring.h
@@ -0,0 +1,163 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _VIRTIO_RING_H_
+#define _VIRTIO_RING_H_
+
+#include <stdint.h>
+
+#include <rte_common.h>
+
+/* This marks a buffer as continuing via the next field. */
+#define VRING_DESC_F_NEXT       1
+/* This marks a buffer as write-only (otherwise read-only). */
+#define VRING_DESC_F_WRITE      2
+/* This means the buffer contains a list of buffer descriptors. */
+#define VRING_DESC_F_INDIRECT   4
+
+/* The Host uses this in used->flags to advise the Guest: don't kick me
+ * when you add a buffer.  It's unreliable, so it's simply an
+ * optimization.  Guest will still kick if it's out of buffers. */
+#define VRING_USED_F_NO_NOTIFY  1
+/* The Guest uses this in avail->flags to advise the Host: don't
+ * interrupt me when you consume a buffer.  It's unreliable, so it's
+ * simply an optimization.  */
+#define VRING_AVAIL_F_NO_INTERRUPT  1
+
+/* VirtIO ring descriptors: 16 bytes.
+ * These can chain together via "next". */
+struct vring_desc {
+	uint64_t addr;  /*  Address (guest-physical). */
+	uint32_t len;   /* Length. */
+	uint16_t flags; /* The flags as indicated above. */
+	uint16_t next;  /* We chain unused descriptors via this. */
+};
+
+struct vring_avail {
+	uint16_t flags;
+	uint16_t idx;
+	uint16_t ring[0];
+};
+
+/* id is a 16bit index. uint32_t is used here for ids for padding reasons. */
+struct vring_used_elem {
+	/* Index of start of used descriptor chain. */
+	uint32_t id;
+	/* Total length of the descriptor chain which was written to. */
+	uint32_t len;
+};
+
+struct vring_used {
+	uint16_t flags;
+	uint16_t idx;
+	struct vring_used_elem ring[0];
+};
+
+struct vring {
+	unsigned int num;
+	struct vring_desc  *desc;
+	struct vring_avail *avail;
+	struct vring_used  *used;
+};
+
+/* The standard layout for the ring is a continuous chunk of memory which
+ * looks like this.  We assume num is a power of 2.
+ *
+ * struct vring {
+ *      // The actual descriptors (16 bytes each)
+ *      struct vring_desc desc[num];
+ *
+ *      // A ring of available descriptor heads with free-running index.
+ *      __u16 avail_flags;
+ *      __u16 avail_idx;
+ *      __u16 available[num];
+ *      __u16 used_event_idx;
+ *
+ *      // Padding to the next align boundary.
+ *      char pad[];
+ *
+ *      // A ring of used descriptor heads with free-running index.
+ *      __u16 used_flags;
+ *      __u16 used_idx;
+ *      struct vring_used_elem used[num];
+ *      __u16 avail_event_idx;
+ * };
+ *
+ * NOTE: for VirtIO PCI, align is 4096.
+ */
+
+/*
+ * We publish the used event index at the end of the available ring, and vice
+ * versa. They are at the end for backwards compatibility.
+ */
+#define vring_used_event(vr)  ((vr)->avail->ring[(vr)->num])
+#define vring_avail_event(vr) (*(uint16_t *)&(vr)->used->ring[(vr)->num])
+
+static inline size_t
+vring_size(unsigned int num, unsigned long align)
+{
+	size_t size;
+
+	size = num * sizeof(struct vring_desc);
+	size += sizeof(struct vring_avail) + (num * sizeof(uint16_t));
+	size = RTE_ALIGN_CEIL(size, align);
+	size += sizeof(struct vring_used) +
+		(num * sizeof(struct vring_used_elem));
+	return size;
+}
+
+static inline void
+vring_init(struct vring *vr, unsigned int num, uint8_t *p,
+	unsigned long align)
+{
+	vr->num = num;
+	vr->desc = (struct vring_desc *) p;
+	vr->avail = (struct vring_avail *) (p +
+		num * sizeof(struct vring_desc));
+	vr->used = (void *)
+		RTE_ALIGN_CEIL((uintptr_t)(&vr->avail->ring[num]), align);
+}
+
+/*
+ * The following is used with VIRTIO_RING_F_EVENT_IDX.
+ * Assuming a given event_idx value from the other size, if we have
+ * just incremented index from old to new_idx, should we trigger an
+ * event?
+ */
+static inline int
+vring_need_event(uint16_t event_idx, uint16_t new_idx, uint16_t old)
+{
+	return (uint16_t)(new_idx - event_idx - 1) < (uint16_t)(new_idx - old);
+}
+
+#endif /* _VIRTIO_RING_H_ */