/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2017, 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.
 */

#ifndef _VIRTIO_PCI_H
#define _VIRTIO_PCI_H

struct vtpci_interrupt {
        struct resource         *vti_irq;
        int                      vti_rid;
        void                    *vti_handler;
};

struct vtpci_virtqueue {
        struct virtqueue        *vtv_vq;
        int                      vtv_no_intr;
        int                      vtv_notify_offset;
};

struct vtpci_common {
        device_t                         vtpci_dev;
        uint64_t                         vtpci_host_features;
        uint64_t                         vtpci_features;
        struct vtpci_virtqueue          *vtpci_vqs;
        int                              vtpci_nvqs;

        uint32_t                         vtpci_flags;
#define VTPCI_FLAG_NO_MSI               0x0001
#define VTPCI_FLAG_NO_MSIX              0x0002
#define VTPCI_FLAG_MODERN               0x0004
#define VTPCI_FLAG_INTX                 0x1000
#define VTPCI_FLAG_MSI                  0x2000
#define VTPCI_FLAG_MSIX                 0x4000
#define VTPCI_FLAG_SHARED_MSIX          0x8000
#define VTPCI_FLAG_ITYPE_MASK           0xF000

        /* The VirtIO PCI "bus" will only ever have one child. */
        device_t                         vtpci_child_dev;
        struct virtio_feature_desc      *vtpci_child_feat_desc;

        /*
         * Ideally, each virtqueue that the driver provides a callback for will
         * receive its own MSIX vector. If there are not sufficient vectors
         * available, then attempt to have all the VQs share one vector. For
         * MSIX, the configuration changed notifications must be on their own
         * vector.
         *
         * If MSIX is not available, attempt to have the whole device share
         * one MSI vector, and then, finally, one intx interrupt.
         */
        struct vtpci_interrupt           vtpci_device_interrupt;
        struct vtpci_interrupt          *vtpci_msix_vq_interrupts;
        int                              vtpci_nmsix_resources;
};

extern int vtpci_disable_msix;

static inline device_t
vtpci_child_device(struct vtpci_common *cn)
{
        return (cn->vtpci_child_dev);
}

static inline bool
vtpci_is_msix_available(struct vtpci_common *cn)
{
        return ((cn->vtpci_flags & VTPCI_FLAG_NO_MSIX) == 0);
}

static inline bool
vtpci_is_msix_enabled(struct vtpci_common *cn)
{
        return ((cn->vtpci_flags & VTPCI_FLAG_MSIX) != 0);
}

static inline bool
vtpci_is_modern(struct vtpci_common *cn)
{
        return ((cn->vtpci_flags & VTPCI_FLAG_MODERN) != 0);
}

static inline int
vtpci_virtqueue_count(struct vtpci_common *cn)
{
        return (cn->vtpci_nvqs);
}

void    vtpci_init(struct vtpci_common *cn, device_t dev, bool modern);
int     vtpci_add_child(struct vtpci_common *cn);
int     vtpci_delete_child(struct vtpci_common *cn);
void    vtpci_child_detached(struct vtpci_common *cn);
int     vtpci_reinit(struct vtpci_common *cn);

uint64_t vtpci_negotiate_features(struct vtpci_common *cn,
             uint64_t child_features, uint64_t host_features);
bool     vtpci_with_feature(struct vtpci_common *cn, uint64_t feature);

int     vtpci_read_ivar(struct vtpci_common *cn, int index, uintptr_t *result);
int     vtpci_write_ivar(struct vtpci_common *cn, int index, uintptr_t value);

int     vtpci_alloc_virtqueues(struct vtpci_common *cn, int nvqs,
            struct vq_alloc_info *vq_info);
int     vtpci_setup_interrupts(struct vtpci_common *cn, enum intr_type type);
void    vtpci_release_child_resources(struct vtpci_common *cn);

#endif /* _VIRTIO_PCI_H */