/*
 * Copyright (c) 2010 Minoura Makoto.
 * Copyright (c) 2012 Nexenta Systems, Inc.
 * 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'' ANDANY 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 __VIRTIOREG_H__
#define	__VIRTIOREG_H__

#include <sys/types.h>

#define	PCI_VENDOR_QUMRANET 0x1af4
#define	PCI_DEV_VIRTIO_MIN 0x1000
#define	PCI_DEV_VIRTIO_MAX 0x103f
#define	VIRTIO_PCI_ABI_VERSION 0

/* Virtio product id (subsystem) */
#define	PCI_PRODUCT_VIRTIO_NETWORK	1
#define	PCI_PRODUCT_VIRTIO_BLOCK	2
#define	PCI_PRODUCT_VIRTIO_CONSOLE	3
#define	PCI_PRODUCT_VIRTIO_ENTROPY	4
#define	PCI_PRODUCT_VIRTIO_BALLOON	5
#define	PCI_PRODUCT_VIRTIO_9P		9

/* Virtio header */
#define	VIRTIO_CONFIG_DEVICE_FEATURES		0 /* 32bit */
#define	VIRTIO_CONFIG_GUEST_FEATURES		4 /* 32bit */

#define	VIRTIO_F_NOTIFY_ON_EMPTY		(1<<24)
#define	VIRTIO_F_RING_INDIRECT_DESC		(1<<28)
#define	VIRTIO_F_BAD_FEATURE			(1<<30)

#define	VIRTIO_CONFIG_QUEUE_ADDRESS		8 /* 32bit */
#define	VIRTIO_CONFIG_QUEUE_SIZE		12 /* 16bit */
#define	VIRTIO_CONFIG_QUEUE_SELECT		14 /* 16bit */
#define	VIRTIO_CONFIG_QUEUE_NOTIFY		16 /* 16bit */
#define	VIRTIO_CONFIG_DEVICE_STATUS		18 /* 8bit */

#define	VIRTIO_CONFIG_DEVICE_STATUS_RESET	0
#define	VIRTIO_CONFIG_DEVICE_STATUS_ACK		1
#define	VIRTIO_CONFIG_DEVICE_STATUS_DRIVER	2
#define	VIRTIO_CONFIG_DEVICE_STATUS_DRIVER_OK	4
#define	VIRTIO_CONFIG_DEVICE_STATUS_FAILED	128

#define	VIRTIO_CONFIG_ISR_STATUS		19 /* 8bit */
#define	VIRTIO_CONFIG_ISR_CONFIG_CHANGE		2

#define	VIRTIO_CONFIG_CONFIG_VECTOR		20 /* 16bit, optional */
#define	VIRTIO_CONFIG_QUEUE_VECTOR		22

#define	VIRTIO_CONFIG_DEVICE_CONFIG_NOMSI	20
#define	VIRTIO_CONFIG_DEVICE_CONFIG_MSI		24

#define	VIRTIO_MSI_NO_VECTOR 0xffff

/* Virtqueue */
/* This marks a buffer as continuing via the next field. */
#define	VRING_DESC_F_NEXT	1
/*
 * This marks a buffer as write-only, from the devices's perspective.
 * (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 {
	/* Address (guest-physical). */
	uint64_t addr;
	/* Length. */
	uint32_t len;
	/* The flags as indicated above. */
	uint16_t flags;
	/* We chain unused descriptors via this, too */
	uint16_t next;
} __attribute__((packed));

struct vring_avail {
	uint16_t flags;
	uint16_t idx;
	uint16_t ring[];
} __attribute__((packed));

/* u32 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;
} __attribute__((packed));

struct vring_used {
	uint16_t flags;
	uint16_t idx;
	struct vring_used_elem ring[];
} __attribute__((packed));


/* Got nothing to do with the system page size, just a confusing name. */
#define	VIRTIO_PAGE_SIZE	(4096)

#endif /* __VIRTIOREG_H__ */