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_FLUSH	9	/* Cache flush command support */
 41#define VIRTIO_BLK_F_TOPOLOGY	10	/* Topology information is available */
 42
 43#define VIRTIO_BLK_ID_BYTES	20	/* ID string length */
 44
 45struct virtio_blk_config {
 46	/* The capacity (in 512-byte sectors). */
 47	__u64 capacity;
 48	/* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
 49	__u32 size_max;
 50	/* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
 51	__u32 seg_max;
 52	/* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */
 53	struct virtio_blk_geometry {
 54		__u16 cylinders;
 55		__u8 heads;
 56		__u8 sectors;
 57	} geometry;
 58
 59	/* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
 60	__u32 blk_size;
 61
 62	/* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY  */
 63	/* exponent for physical block per logical block. */
 64	__u8 physical_block_exp;
 65	/* alignment offset in logical blocks. */
 66	__u8 alignment_offset;
 67	/* minimum I/O size without performance penalty in logical blocks. */
 68	__u16 min_io_size;
 69	/* optimal sustained I/O size in logical blocks. */
 70	__u32 opt_io_size;
 71
 72} __attribute__((packed));
 73
 74/*
 75 * Command types
 76 *
 77 * Usage is a bit tricky as some bits are used as flags and some are not.
 78 *
 79 * Rules:
 80 *   VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
 81 *   VIRTIO_BLK_T_BARRIER.  VIRTIO_BLK_T_FLUSH is a command of its own
 82 *   and may not be combined with any of the other flags.
 83 */
 84
 85/* These two define direction. */
 86#define VIRTIO_BLK_T_IN		0
 87#define VIRTIO_BLK_T_OUT	1
 88
 89/* This bit says it's a scsi command, not an actual read or write. */
 90#define VIRTIO_BLK_T_SCSI_CMD	2
 91
 92/* Cache flush command */
 93#define VIRTIO_BLK_T_FLUSH	4
 94
 95/* Get device ID command */
 96#define VIRTIO_BLK_T_GET_ID    8
 97
 98/* Barrier before this op. */
 99#define VIRTIO_BLK_T_BARRIER	0x80000000
100
101/* This is the first element of the read scatter-gather list. */
102struct virtio_blk_outhdr {
103	/* VIRTIO_BLK_T* */
104	__u32 type;
105	/* io priority. */
106	__u32 ioprio;
107	/* Sector (ie. 512 byte offset) */
108	__u64 sector;
109};
110
111struct virtio_scsi_inhdr {
112	__u32 errors;
113	__u32 data_len;
114	__u32 sense_len;
115	__u32 residual;
116};
117
118/* And this is the final byte of the write scatter-gather list. */
119#define VIRTIO_BLK_S_OK		0
120#define VIRTIO_BLK_S_IOERR	1
121#define VIRTIO_BLK_S_UNSUPP	2
122#endif /* _LINUX_VIRTIO_BLK_H */