virtqueue.h

Go to the documentation of this file.

#ifndef VIRTQUEUE_H_
#define VIRTQUEUE_H_
 
/*-
 * Copyright (c) 2011, Bryan Venteicher <bryanv@FreeBSD.org>
 * All rights reserved.
 *
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * $FreeBSD$
 */
 
#include <stdbool.h>
#include <stdint.h>
 
#if defined __cplusplus
extern "C" {
#endif
 
#include <openamp/virtio_ring.h>
#include <metal/alloc.h>
#include <metal/io.h>
 
/* Error Codes */
#define VQ_ERROR_BASE                                 -3000
#define ERROR_VRING_FULL                              (VQ_ERROR_BASE - 1)
#define ERROR_INVLD_DESC_IDX                          (VQ_ERROR_BASE - 2)
#define ERROR_EMPTY_RING                              (VQ_ERROR_BASE - 3)
#define ERROR_NO_MEM                                  (VQ_ERROR_BASE - 4)
#define ERROR_VRING_MAX_DESC                          (VQ_ERROR_BASE - 5)
#define ERROR_VRING_ALIGN                             (VQ_ERROR_BASE - 6)
#define ERROR_VRING_NO_BUFF                           (VQ_ERROR_BASE - 7)
#define ERROR_VQUEUE_INVLD_PARAM                      (VQ_ERROR_BASE - 8)
 
#define VQUEUE_SUCCESS                                0
 
/* The maximum virtqueue size is 2^15. Use that value as the end of
 * descriptor chain terminator since it will never be a valid index
 * in the descriptor table. This is used to verify we are correctly
 * handling vq_free_cnt.
 */
#define VQ_RING_DESC_CHAIN_END                         32768
 
/* 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)
 
struct virtqueue_buf {
        void *buf;
        int len;
};
 
struct vq_desc_extra {
        void *cookie;
        uint16_t ndescs;
};
 
struct virtqueue {
        struct virtio_device *vq_dev;
        const char *vq_name;
        uint16_t vq_queue_index;
        uint16_t vq_nentries;
        void (*callback)(struct virtqueue *vq);
        void (*notify)(struct virtqueue *vq);
        struct vring vq_ring;
        uint16_t vq_free_cnt;
        uint16_t vq_queued_cnt;
        void *shm_io; /* opaque pointer to data needed to allow v2p & p2v */
 
        /*
         * Head of the free chain in the descriptor table. If
         * there are no free descriptors, this will be set to
         * VQ_RING_DESC_CHAIN_END.
         */
        uint16_t vq_desc_head_idx;
 
        /*
         * Last consumed descriptor in the used table,
         * trails vq_ring.used->idx.
         */
        uint16_t vq_used_cons_idx;
 
        /*
         * Last consumed descriptor in the available table -
         * used by the consumer side.
         */
        uint16_t vq_available_idx;
 
#ifdef VQUEUE_DEBUG
        bool vq_inuse;
#endif
 
        /*
         * Used by the host side during callback. Cookie
         * holds the address of buffer received from other side.
         * Other fields in this structure are not used currently.
         */
 
        struct vq_desc_extra vq_descx[0];
};
 
/* struct to hold vring specific information */
struct vring_alloc_info {
        void *vaddr;
        uint32_t align;
        uint16_t num_descs;
        uint16_t pad;
};
 
typedef void (*vq_callback)(struct virtqueue *);
typedef void (*vq_notify)(struct virtqueue *);
 
#ifdef VQUEUE_DEBUG
#include <metal/log.h>
#include <metal/assert.h>
 
#define VQASSERT(_vq, _exp, _msg) \
        do { \
                if (!(_exp)) { \
                        metal_log(METAL_LOG_EMERGENCY, \
                                  "%s: %s - "_msg, __func__, (_vq)->vq_name); \
                        metal_assert(_exp); \
                } \
        } while (0)
 
#define VQ_RING_ASSERT_VALID_IDX(_vq, _idx)            \
        VQASSERT((_vq), (_idx) < (_vq)->vq_nentries, "invalid ring index")
 
#define VQ_RING_ASSERT_CHAIN_TERM(_vq)                \
        VQASSERT((_vq), (_vq)->vq_desc_head_idx ==            \
        VQ_RING_DESC_CHAIN_END, \
        "full ring terminated incorrectly: invalid head")
 
#define VQ_PARAM_CHK(condition, status_var, status_err) \
        do {                                            \
                if (((status_var) == 0) && (condition)) { \
                        status_var = status_err;        \
                }                                       \
        } while (0)
 
#define VQUEUE_BUSY(vq) \
        do {                                                 \
                if (!(vq)->vq_inuse)                 \
                        (vq)->vq_inuse = true;               \
                else                                         \
                        VQASSERT(vq, !(vq)->vq_inuse,\
                                "VirtQueue already in use");  \
        } while (0)
 
#define VQUEUE_IDLE(vq)            ((vq)->vq_inuse = false)
 
#else
 
#define VQASSERT(_vq, _exp, _msg)
#define VQ_RING_ASSERT_VALID_IDX(_vq, _idx)
#define VQ_RING_ASSERT_CHAIN_TERM(_vq)
#define VQ_PARAM_CHK(condition, status_var, status_err)
#define VQUEUE_BUSY(vq)
#define VQUEUE_IDLE(vq)
 
#endif
 
int virtqueue_create(struct virtio_device *device, unsigned short id,
                     const char *name, struct vring_alloc_info *ring,
                     void (*callback)(struct virtqueue *vq),
                     void (*notify)(struct virtqueue *vq),
                     struct virtqueue *vq);
 
/*
 * virtqueue_set_shmem_io
 *
 * set virtqueue shared memory I/O region
 *
 * @vq - virt queue
 * @io - pointer to the shared memory I/O region
 */
static inline void virtqueue_set_shmem_io(struct virtqueue *vq,
                                          struct metal_io_region *io)
{
        vq->shm_io = io;
}
 
int virtqueue_add_buffer(struct virtqueue *vq, struct virtqueue_buf *buf_list,
                         int readable, int writable, void *cookie);
 
void *virtqueue_get_buffer(struct virtqueue *vq, uint32_t *len, uint16_t *idx);
 
void *virtqueue_get_available_buffer(struct virtqueue *vq, uint16_t *avail_idx,
                                     uint32_t *len);
 
int virtqueue_add_consumed_buffer(struct virtqueue *vq, uint16_t head_idx,
                                  uint32_t len);
 
void virtqueue_disable_cb(struct virtqueue *vq);
 
int virtqueue_enable_cb(struct virtqueue *vq);
 
void virtqueue_kick(struct virtqueue *vq);
 
static inline struct virtqueue *virtqueue_allocate(unsigned int num_desc_extra)
{
        struct virtqueue *vqs;
        uint32_t vq_size = sizeof(struct virtqueue) +
                 num_desc_extra * sizeof(struct vq_desc_extra);
 
        vqs = (struct virtqueue *)metal_allocate_memory(vq_size);
        if (vqs) {
                memset(vqs, 0x00, vq_size);
        }
 
        return vqs;
}
 
void virtqueue_free(struct virtqueue *vq);
 
void virtqueue_dump(struct virtqueue *vq);
 
void virtqueue_notification(struct virtqueue *vq);
 
uint32_t virtqueue_get_desc_size(struct virtqueue *vq);
 
uint32_t virtqueue_get_buffer_length(struct virtqueue *vq, uint16_t idx);
void *virtqueue_get_buffer_addr(struct virtqueue *vq, uint16_t idx);
 
#if defined __cplusplus
}
#endif
 
#endif                          /* VIRTQUEUE_H_ */