freebsd-skq/sys/dev/virtio/virtqueue.h
Bryan Venteicher b619f40aec Add support for postponing VirtIO virtqueue interrupts
Partial support for the EVENT_IDX feature was added a while ago,
but this commit adds an interface for the device driver to hint
how long (in terms of descriptors) the next interrupt should be
delayed.

The first user of this will be used to reduce VirtIO net's Tx
completion interrupts.
2013-09-01 04:16:43 +00:00

105 lines
3.8 KiB
C

/*-
* Copyright (c) 2011, Bryan Venteicher <bryanv@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
* $FreeBSD$
*/
#ifndef _VIRTIO_VIRTQUEUE_H
#define _VIRTIO_VIRTQUEUE_H
struct virtqueue;
struct sglist;
/* Support for indirect buffer descriptors. */
#define VIRTIO_RING_F_INDIRECT_DESC (1 << 28)
/* Support to suppress interrupt until specific index is reached. */
#define VIRTIO_RING_F_EVENT_IDX (1 << 29)
/* Device callback for a virtqueue interrupt. */
typedef void virtqueue_intr_t(void *);
/*
* Hint on how long the next interrupt should be postponed. This is
* only used when the EVENT_IDX feature is negotiated.
*/
typedef enum {
VQ_POSTPONE_SHORT,
VQ_POSTPONE_LONG,
VQ_POSTPONE_EMPTIED /* Until all available desc are used. */
} vq_postpone_t;
#define VIRTQUEUE_MAX_NAME_SZ 32
/* One for each virtqueue the device wishes to allocate. */
struct vq_alloc_info {
char vqai_name[VIRTQUEUE_MAX_NAME_SZ];
int vqai_maxindirsz;
virtqueue_intr_t *vqai_intr;
void *vqai_intr_arg;
struct virtqueue **vqai_vq;
};
#define VQ_ALLOC_INFO_INIT(_i,_nsegs,_intr,_arg,_vqp,_str,...) do { \
snprintf((_i)->vqai_name, VIRTQUEUE_MAX_NAME_SZ, _str, \
##__VA_ARGS__); \
(_i)->vqai_maxindirsz = (_nsegs); \
(_i)->vqai_intr = (_intr); \
(_i)->vqai_intr_arg = (_arg); \
(_i)->vqai_vq = (_vqp); \
} while (0)
uint64_t virtqueue_filter_features(uint64_t features);
int virtqueue_alloc(device_t dev, uint16_t queue, uint16_t size,
int align, vm_paddr_t highaddr, struct vq_alloc_info *info,
struct virtqueue **vqp);
void *virtqueue_drain(struct virtqueue *vq, int *last);
void virtqueue_free(struct virtqueue *vq);
int virtqueue_reinit(struct virtqueue *vq, uint16_t size);
int virtqueue_intr_filter(struct virtqueue *vq);
void virtqueue_intr(struct virtqueue *vq);
int virtqueue_enable_intr(struct virtqueue *vq);
int virtqueue_postpone_intr(struct virtqueue *vq, vq_postpone_t hint);
void virtqueue_disable_intr(struct virtqueue *vq);
/* Get physical address of the virtqueue ring. */
vm_paddr_t virtqueue_paddr(struct virtqueue *vq);
int virtqueue_full(struct virtqueue *vq);
int virtqueue_empty(struct virtqueue *vq);
int virtqueue_size(struct virtqueue *vq);
int virtqueue_nused(struct virtqueue *vq);
void virtqueue_notify(struct virtqueue *vq);
void virtqueue_dump(struct virtqueue *vq);
int virtqueue_enqueue(struct virtqueue *vq, void *cookie,
struct sglist *sg, int readable, int writable);
void *virtqueue_dequeue(struct virtqueue *vq, uint32_t *len);
void *virtqueue_poll(struct virtqueue *vq, uint32_t *len);
#endif /* _VIRTIO_VIRTQUEUE_H */