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/*-
* This header is BSD licensed so anyone can use the definitions to implement
* compatible drivers/servers.
*
* 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'' 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 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.
*
* $FreeBSD$
*/
#ifndef _VIRTIO_BLK_H
#define _VIRTIO_BLK_H
/* Feature bits */
#define VIRTIO_BLK_F_BARRIER 0x0001 /* Does host support barriers? */
#define VIRTIO_BLK_F_SIZE_MAX 0x0002 /* Indicates maximum segment size */
#define VIRTIO_BLK_F_SEG_MAX 0x0004 /* Indicates maximum # of segments */
#define VIRTIO_BLK_F_GEOMETRY 0x0010 /* Legacy geometry available */
#define VIRTIO_BLK_F_RO 0x0020 /* Disk is read-only */
#define VIRTIO_BLK_F_BLK_SIZE 0x0040 /* Block size of disk is available*/
#define VIRTIO_BLK_F_SCSI 0x0080 /* Supports scsi command passthru */
#define VIRTIO_BLK_F_WCE 0x0200 /* Writeback mode enabled after reset */
#define VIRTIO_BLK_F_TOPOLOGY 0x0400 /* Topology information is available */
#define VIRTIO_BLK_F_CONFIG_WCE 0x0800 /* Writeback mode available in config */
#define VIRTIO_BLK_ID_BYTES 20 /* ID string length */
struct virtio_blk_config {
/* The capacity (in 512-byte sectors). */
uint64_t capacity;
/* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
uint32_t size_max;
/* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
uint32_t seg_max;
/* Geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */
struct virtio_blk_geometry {
uint16_t cylinders;
uint8_t heads;
uint8_t sectors;
} geometry;
/* Block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
uint32_t blk_size;
/* Topology of the device (if VIRTIO_BLK_F_TOPOLOGY) */
struct virtio_blk_topology {
uint8_t physical_block_exp;
uint8_t alignment_offset;
uint16_t min_io_size;
uint16_t opt_io_size;
} topology;
/* Writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
uint8_t writeback;
} __packed;
/*
* Command types
*
* Usage is a bit tricky as some bits are used as flags and some are not.
*
* Rules:
* VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
* VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own
* and may not be combined with any of the other flags.
*/
/* These two define direction. */
#define VIRTIO_BLK_T_IN 0
#define VIRTIO_BLK_T_OUT 1
/* This bit says it's a scsi command, not an actual read or write. */
#define VIRTIO_BLK_T_SCSI_CMD 2
/* Cache flush command */
#define VIRTIO_BLK_T_FLUSH 4
/* Get device ID command */
#define VIRTIO_BLK_T_GET_ID 8
/* Barrier before this op. */
#define VIRTIO_BLK_T_BARRIER 0x80000000
/* ID string length */
#define VIRTIO_BLK_ID_BYTES 20
/* This is the first element of the read scatter-gather list. */
struct virtio_blk_outhdr {
/* VIRTIO_BLK_T* */
uint32_t type;
/* io priority. */
uint32_t ioprio;
/* Sector (ie. 512 byte offset) */
uint64_t sector;
};
struct virtio_scsi_inhdr {
uint32_t errors;
uint32_t data_len;
uint32_t sense_len;
uint32_t residual;
};
/* And this is the final byte of the write scatter-gather list. */
#define VIRTIO_BLK_S_OK 0
#define VIRTIO_BLK_S_IOERR 1
#define VIRTIO_BLK_S_UNSUPP 2
#endif /* _VIRTIO_BLK_H */
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