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#ifndef _LINUX_VIRTIO_BLK_H

#define _LINUX_VIRTIO_BLK_H

/* 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. */

#include <linux/types.h>

#include <linux/virtio_ids.h>

#include <linux/virtio_config.h>

/* Feature bits */

#define VIRTIO_BLK_F_BARRIER    0        /* Does host support barriers? */

#define VIRTIO_BLK_F_SIZE_MAX   1       /* Indicates maximum segment size */

#define VIRTIO_BLK_F_SEG_MAX    2       /* Indicates maximum # of segments */

#define VIRTIO_BLK_F_GEOMETRY   4       /* Legacy geometry available  */

#define VIRTIO_BLK_F_RO         5       /* Disk is read-only */

#define VIRTIO_BLK_F_BLK_SIZE   6       /* Block size of disk is available*/

#define VIRTIO_BLK_F_SCSI       7       /* Supports scsi command passthru */

#define VIRTIO_BLK_F_WCE        9       /* Writeback mode enabled after reset */

#define VIRTIO_BLK_F_TOPOLOGY   10      /* Topology information is available */

#define VIRTIO_BLK_F_CONFIG_WCE 11      /* Writeback mode available in config */

/* Old (deprecated) name for VIRTIO_BLK_F_WCE. */

#define VIRTIO_BLK_F_FLUSH VIRTIO_BLK_F_WCE

#define VIRTIO_BLK_ID_BYTES     20      /* ID string length */

struct virtio_blk_config {

        /* The capacity (in 512-byte sectors). */

        __u64 capacity;

        /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */

        __u32 size_max;

        /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */

        __u32 seg_max;

        /* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */

        struct virtio_blk_geometry {

                __u16 cylinders;

                __u8 heads;

                __u8 sectors;

        } geometry;

        /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */

        __u32 blk_size;

        /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY  */

        /* exponent for physical block per logical block. */

        __u8 physical_block_exp;

        /* alignment offset in logical blocks. */

        __u8 alignment_offset;

        /* minimum I/O size without performance penalty in logical blocks. */

        __u16 min_io_size;

        /* optimal sustained I/O size in logical blocks. */

        __u32 opt_io_size;

        /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */

        __u8 wce;

} __attribute__((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

/* This is the first element of the read scatter-gather list. */

struct virtio_blk_outhdr {

        /* VIRTIO_BLK_T* */

        __u32 type;

        /* io priority. */

        __u32 ioprio;

        /* Sector (ie. 512 byte offset) */

        __u64 sector;

};

struct virtio_scsi_inhdr {

        __u32 errors;

        __u32 data_len;

        __u32 sense_len;

        __u32 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 /* _LINUX_VIRTIO_BLK_H */