1/*-
2 * This header is BSD licensed so anyone can use the definitions to implement
3 * compatible drivers/servers.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of IBM nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18 *  TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31#ifndef _VIRTIO_BLK_H
32#define _VIRTIO_BLK_H
33
34/* Feature bits */
35#define VIRTIO_BLK_F_BARRIER	0x0001	/* Does host support barriers? */
36#define VIRTIO_BLK_F_SIZE_MAX	0x0002	/* Indicates maximum segment size */
37#define VIRTIO_BLK_F_SEG_MAX	0x0004	/* Indicates maximum # of segments */
38#define VIRTIO_BLK_F_GEOMETRY	0x0010	/* Legacy geometry available  */
39#define VIRTIO_BLK_F_RO		0x0020	/* Disk is read-only */
40#define VIRTIO_BLK_F_BLK_SIZE	0x0040	/* Block size of disk is available*/
41#define VIRTIO_BLK_F_SCSI	0x0080	/* Supports scsi command passthru */
42#define VIRTIO_BLK_F_FLUSH	0x0200	/* Flush command supported */
43#define VIRTIO_BLK_F_TOPOLOGY	0x0400	/* Topology information is available */
44#define VIRTIO_BLK_F_CONFIG_WCE 0x0800	/* Writeback mode available in config */
45
46#define VIRTIO_BLK_ID_BYTES	20	/* ID string length */
47
48struct virtio_blk_config {
49	/* The capacity (in 512-byte sectors). */
50	uint64_t capacity;
51	/* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
52	uint32_t size_max;
53	/* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
54	uint32_t seg_max;
55	/* Geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */
56	struct virtio_blk_geometry {
57		uint16_t cylinders;
58		uint8_t heads;
59		uint8_t sectors;
60	} geometry;
61
62	/* Block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
63	uint32_t blk_size;
64
65	/* Topology of the device (if VIRTIO_BLK_F_TOPOLOGY) */
66	struct virtio_blk_topology {
67		uint8_t physical_block_exp;
68		uint8_t alignment_offset;
69		uint16_t min_io_size;
70		uint32_t opt_io_size;
71	} topology;
72
73	/* Writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
74	uint8_t writeback;
75
76} __packed;
77
78/*
79 * Command types
80 *
81 * Usage is a bit tricky as some bits are used as flags and some are not.
82 *
83 * Rules:
84 *   VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
85 *   VIRTIO_BLK_T_BARRIER.  VIRTIO_BLK_T_FLUSH is a command of its own
86 *   and may not be combined with any of the other flags.
87 */
88
89/* These two define direction. */
90#define VIRTIO_BLK_T_IN		0
91#define VIRTIO_BLK_T_OUT	1
92
93/* This bit says it's a scsi command, not an actual read or write. */
94#define VIRTIO_BLK_T_SCSI_CMD	2
95
96/* Cache flush command */
97#define VIRTIO_BLK_T_FLUSH	4
98
99/* Get device ID command */
100#define VIRTIO_BLK_T_GET_ID	8
101
102/* Barrier before this op. */
103#define VIRTIO_BLK_T_BARRIER	0x80000000
104
105/* ID string length */
106#define VIRTIO_BLK_ID_BYTES	20
107
108/* This is the first element of the read scatter-gather list. */
109struct virtio_blk_outhdr {
110	/* VIRTIO_BLK_T* */
111	uint32_t type;
112	/* io priority. */
113	uint32_t ioprio;
114	/* Sector (ie. 512 byte offset) */
115	uint64_t sector;
116};
117
118struct virtio_scsi_inhdr {
119	uint32_t errors;
120	uint32_t data_len;
121	uint32_t sense_len;
122	uint32_t residual;
123};
124
125/* And this is the final byte of the write scatter-gather list. */
126#define VIRTIO_BLK_S_OK		0
127#define VIRTIO_BLK_S_IOERR	1
128#define VIRTIO_BLK_S_UNSUPP	2
129
130#endif /* _VIRTIO_BLK_H */
131