1#ifndef _LINUX_VIRTIO_BLK_H
2#define _LINUX_VIRTIO_BLK_H
3/* This header is BSD licensed so anyone can use the definitions to implement
4 * compatible drivers/servers.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of IBM nor the names of its contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE. */
28#include <linux/types.h>
29#include <linux/virtio_ids.h>
30#include <linux/virtio_config.h>
31
32/* Feature bits */
33#define VIRTIO_BLK_F_BARRIER	0	/* Does host support barriers? */
34#define VIRTIO_BLK_F_SIZE_MAX	1	/* Indicates maximum segment size */
35#define VIRTIO_BLK_F_SEG_MAX	2	/* Indicates maximum # of segments */
36#define VIRTIO_BLK_F_GEOMETRY	4	/* Legacy geometry available  */
37#define VIRTIO_BLK_F_RO		5	/* Disk is read-only */
38#define VIRTIO_BLK_F_BLK_SIZE	6	/* Block size of disk is available*/
39#define VIRTIO_BLK_F_SCSI	7	/* Supports scsi command passthru */
40#define VIRTIO_BLK_F_WCE	9	/* Writeback mode enabled after reset */
41#define VIRTIO_BLK_F_TOPOLOGY	10	/* Topology information is available */
42#define VIRTIO_BLK_F_CONFIG_WCE	11	/* Writeback mode available in config */
43
44#ifndef __KERNEL__
45/* Old (deprecated) name for VIRTIO_BLK_F_WCE. */
46#define VIRTIO_BLK_F_FLUSH VIRTIO_BLK_F_WCE
47#endif
48
49#define VIRTIO_BLK_ID_BYTES	20	/* ID string length */
50
51struct virtio_blk_config {
52	/* The capacity (in 512-byte sectors). */
53	__u64 capacity;
54	/* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
55	__u32 size_max;
56	/* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
57	__u32 seg_max;
58	/* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */
59	struct virtio_blk_geometry {
60		__u16 cylinders;
61		__u8 heads;
62		__u8 sectors;
63	} geometry;
64
65	/* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
66	__u32 blk_size;
67
68	/* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY  */
69	/* exponent for physical block per logical block. */
70	__u8 physical_block_exp;
71	/* alignment offset in logical blocks. */
72	__u8 alignment_offset;
73	/* minimum I/O size without performance penalty in logical blocks. */
74	__u16 min_io_size;
75	/* optimal sustained I/O size in logical blocks. */
76	__u32 opt_io_size;
77
78	/* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
79	__u8 wce;
80} __attribute__((packed));
81
82/*
83 * Command types
84 *
85 * Usage is a bit tricky as some bits are used as flags and some are not.
86 *
87 * Rules:
88 *   VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
89 *   VIRTIO_BLK_T_BARRIER.  VIRTIO_BLK_T_FLUSH is a command of its own
90 *   and may not be combined with any of the other flags.
91 */
92
93/* These two define direction. */
94#define VIRTIO_BLK_T_IN		0
95#define VIRTIO_BLK_T_OUT	1
96
97/* This bit says it's a scsi command, not an actual read or write. */
98#define VIRTIO_BLK_T_SCSI_CMD	2
99
100/* Cache flush command */
101#define VIRTIO_BLK_T_FLUSH	4
102
103/* Get device ID command */
104#define VIRTIO_BLK_T_GET_ID    8
105
106/* Barrier before this op. */
107#define VIRTIO_BLK_T_BARRIER	0x80000000
108
109/* This is the first element of the read scatter-gather list. */
110struct virtio_blk_outhdr {
111	/* VIRTIO_BLK_T* */
112	__u32 type;
113	/* io priority. */
114	__u32 ioprio;
115	/* Sector (ie. 512 byte offset) */
116	__u64 sector;
117};
118
119struct virtio_scsi_inhdr {
120	__u32 errors;
121	__u32 data_len;
122	__u32 sense_len;
123	__u32 residual;
124};
125
126/* And this is the final byte of the write scatter-gather list. */
127#define VIRTIO_BLK_S_OK		0
128#define VIRTIO_BLK_S_IOERR	1
129#define VIRTIO_BLK_S_UNSUPP	2
130#endif /* _LINUX_VIRTIO_BLK_H */
131