/*      $OpenBSD: virtiovar.h,v 1.29 2025/01/29 14:03:19 sf Exp $       */
/*      $NetBSD: virtiovar.h,v 1.1 2011/10/30 12:12:21 hannken Exp $    */

/*
 * Copyright (c) 2012 Stefan Fritsch.
 * Copyright (c) 2010 Minoura Makoto.
 * 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, 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.
 */

/*
 * Part of the file derived from `Virtio PCI Card Specification v0.8.6 DRAFT'
 * Appendix A.
 */
/* An interface for efficient virtio implementation.
 *
 * This header is BSD licensed so anyone can use the definitions
 * to implement compatible drivers/servers.
 *
 * Copyright 2007, 2009, IBM Corporation
 * 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, 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.
 * 3. Neither the name of IBM 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 IBM 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 _DEV_PV_VIRTIOVAR_H_
#define _DEV_PV_VIRTIOVAR_H_

#include <sys/param.h>
#include <sys/queue.h>
#include <sys/device.h>
#include <sys/mutex.h>
#include <machine/bus.h>

#include <dev/pv/virtioreg.h>

#ifndef VIRTIO_DEBUG
#define VIRTIO_DEBUG            0
#endif

/* flags for config(8) */
#define VIRTIO_CF_NO_INDIRECT           1
#define VIRTIO_CF_NO_EVENT_IDX          2
#define VIRTIO_CF_PREFER_VERSION_09     8

struct virtio_attach_args {
        int                      va_devid;      /* virtio device id */
        unsigned int             va_nintr;      /* number of intr vectors */
};

struct vq_entry {
        SLIST_ENTRY(vq_entry)    qe_list;       /* free list */
        uint16_t                 qe_index;      /* index in vq_desc array */

        /* The following are used only in the `head' entry */
        int16_t                  qe_next;       /* next enq slot */
        int16_t                  qe_indirect;   /* 1 if using indirect */
        int16_t                  qe_vr_index;   /* index in sc_reqs array */
        struct vring_desc       *qe_desc_base;  /* pointer to vd array */
};

struct virtqueue {
        struct virtio_softc     *vq_owner;
        unsigned int            vq_num;  /* queue size (# of entries),
                                          * 0 if unused/non-existant */
        unsigned int            vq_mask; /* (1 << vq_num - 1) */
        int                     vq_index; /* queue number (0, 1, ...) */

        /* vring pointers (KVA) */
        struct vring_desc       *vq_desc;
        struct vring_avail      *vq_avail;
        struct vring_used       *vq_used;
        void                    *vq_indirect;

        /* virtqueue allocation info */
        void                    *vq_vaddr;
        int                     vq_availoffset;
        int                     vq_usedoffset;
        int                     vq_indirectoffset;
        bus_dma_segment_t       vq_segs[1];
        unsigned int            vq_bytesize;
        bus_dmamap_t            vq_dmamap;

        int                     vq_maxnsegs;

        /* free entry management */
        struct vq_entry         *vq_entries;
        SLIST_HEAD(, vq_entry) vq_freelist;

        /* enqueue/dequeue status */
        uint16_t                vq_avail_idx;
        uint16_t                vq_used_idx;
        int                     vq_queued;

        /* interrupt handler */
        int                     (*vq_done)(struct virtqueue*);
        /* 1.x only: offset for notify address calculation */
        uint32_t                vq_notify_off;
        int                     vq_intr_vec;
};

struct virtio_feature_name {
        uint64_t         bit;
        const char      *name;
};

struct virtio_ops {
        void            (*kick)(struct virtio_softc *, uint16_t);
        uint8_t         (*read_dev_cfg_1)(struct virtio_softc *, int);
        uint16_t        (*read_dev_cfg_2)(struct virtio_softc *, int);
        uint32_t        (*read_dev_cfg_4)(struct virtio_softc *, int);
        uint64_t        (*read_dev_cfg_8)(struct virtio_softc *, int);
        void            (*write_dev_cfg_1)(struct virtio_softc *, int, uint8_t);
        void            (*write_dev_cfg_2)(struct virtio_softc *, int, uint16_t);
        void            (*write_dev_cfg_4)(struct virtio_softc *, int, uint32_t);
        void            (*write_dev_cfg_8)(struct virtio_softc *, int, uint64_t);
        uint16_t        (*read_queue_size)(struct virtio_softc *, uint16_t);
        void            (*setup_queue)(struct virtio_softc *, struct virtqueue *, uint64_t);
        void            (*setup_intrs)(struct virtio_softc *);
        int             (*get_status)(struct virtio_softc *);
        void            (*set_status)(struct virtio_softc *, int);
        int             (*neg_features)(struct virtio_softc *, const struct virtio_feature_name *);
        int             (*attach_finish)(struct virtio_softc *, struct virtio_attach_args *);
        int             (*poll_intr)(void *);
        void            (*intr_barrier)(struct virtio_softc *);
        int             (*intr_establish)(struct virtio_softc *, struct virtio_attach_args *,
                            int, struct cpu_info *, int (*)(void *), void *);
};

#define VIRTIO_CHILD_ERROR      ((void*)1)

struct virtio_softc {
        struct device            sc_dev;
        bus_dma_tag_t            sc_dmat;       /* set by transport */
        const struct virtio_ops *sc_ops;        /* set by transport */

        int                      sc_ipl;                /* set by child */

        uint64_t                 sc_driver_features;
        uint64_t                 sc_active_features;
        int                      sc_indirect;
        int                      sc_version_1;

        int                      sc_nvqs;       /* size of sc_vqs, set by child */
        struct virtqueue        *sc_vqs;        /* set by child */

        struct device           *sc_child;      /* set by child,
                                                 * VIRTIO_CHILD_ERROR on error
                                                 */
        int                     (*sc_config_change)(struct virtio_softc*);
                                                /* set by child */
};

/* public interface */
#define virtio_read_device_config_1(sc, o)      (sc)->sc_ops->read_dev_cfg_1(sc, o)
#define virtio_read_device_config_2(sc, o)      (sc)->sc_ops->read_dev_cfg_2(sc, o)
#define virtio_read_device_config_4(sc, o)      (sc)->sc_ops->read_dev_cfg_4(sc, o)
#define virtio_read_device_config_8(sc, o)      (sc)->sc_ops->read_dev_cfg_8(sc, o)
#define virtio_write_device_config_1(sc, o, v)  (sc)->sc_ops->write_dev_cfg_1(sc, o, v)
#define virtio_write_device_config_2(sc, o, v)  (sc)->sc_ops->write_dev_cfg_2(sc, o, v)
#define virtio_write_device_config_4(sc, o, v)  (sc)->sc_ops->write_dev_cfg_4(sc, o, v)
#define virtio_write_device_config_8(sc, o, v)  (sc)->sc_ops->write_dev_cfg_8(sc, o, v)
#define virtio_read_queue_size(sc, i)           (sc)->sc_ops->read_queue_size(sc, i)
#define virtio_setup_queue(sc, i, v)            (sc)->sc_ops->setup_queue(sc, i, v)
#define virtio_negotiate_features(sc, n)        (sc)->sc_ops->neg_features(sc, n)
#define virtio_poll_intr(sc)                    (sc)->sc_ops->poll_intr(sc)
#define virtio_get_status(sc)                   (sc)->sc_ops->get_status(sc)
#define virtio_set_status(sc, i)                (sc)->sc_ops->set_status(sc, i)
#define virtio_intr_barrier(sc)                 (sc)->sc_ops->intr_barrier(sc)

/*
 * virtio_intr_establish() only works if va_nintr > 1. If it is called by a
 * child driver, the transport driver will skip automatic intr allocation and
 * the child driver must allocate all required interrupts itself. Vector 0 is
 * always used for the config change interrupt.
 */
#define virtio_intr_establish(sc, va, v, ci, fn, a)     (sc)->sc_ops->intr_establish(sc, va, v, ci, fn, a)

/* only for transport drivers */
#define virtio_device_reset(sc)                 virtio_set_status((sc), 0)

static inline int
virtio_has_feature(struct virtio_softc *sc, uint64_t fbit)
{
        if (sc->sc_active_features & fbit)
                return 1;
        return 0;
}

int virtio_alloc_vq(struct virtio_softc*, struct virtqueue*, int, int,
                    const char*);
int virtio_free_vq(struct virtio_softc*, struct virtqueue*);
int virtio_attach_finish(struct virtio_softc *, struct virtio_attach_args *);
void virtio_reset(struct virtio_softc *);
void virtio_reinit_start(struct virtio_softc *);
void virtio_reinit_end(struct virtio_softc *);

int virtio_enqueue_prep(struct virtqueue*, int*);
int virtio_enqueue_reserve(struct virtqueue*, int, int);
int virtio_enqueue(struct virtqueue*, int, bus_dmamap_t, int);
int virtio_enqueue_p(struct virtqueue*, int, bus_dmamap_t, bus_addr_t,
                     bus_size_t, int);
void virtio_enqueue_commit(struct virtio_softc*, struct virtqueue*, int, int);
#define         virtio_notify(sc,vq)    virtio_enqueue_commit(sc, vq, -1, 1)

int virtio_enqueue_abort(struct virtqueue*, int);
void virtio_enqueue_trim(struct virtqueue*, int, int);

int virtio_dequeue(struct virtio_softc*, struct virtqueue*, int *, int *);
int virtio_dequeue_commit(struct virtqueue*, int);

int virtio_check_vqs(struct virtio_softc *);
int virtio_check_vq(struct virtio_softc *, struct virtqueue *);
void virtio_stop_vq_intr(struct virtio_softc *, struct virtqueue *);
int virtio_start_vq_intr(struct virtio_softc *, struct virtqueue *);

const char *virtio_device_string(int);
#if VIRTIO_DEBUG
void virtio_log_features(uint64_t, uint64_t, const struct virtio_feature_name *);
void virtio_vq_dump(struct virtqueue *vq);
#endif
int virtio_nused(struct virtqueue *vq);
int virtio_postpone_intr(struct virtqueue *vq, uint16_t nslots);
int virtio_postpone_intr_smart(struct virtqueue *vq);
int virtio_postpone_intr_far(struct virtqueue *vq);

#endif /* _DEV_PV_VIRTIOVAR_H_ */