src/add-ons/kernel/drivers/disk/virtual/virtio_block/virtio_blk.h

   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  /* Cache flush command support */
  43 #define VIRTIO_BLK_F_TOPOLOGY   0x0400  /* Topology information is available */
  44
  45 #define VIRTIO_BLK_ID_BYTES     20      /* ID string length */
  46
  47 struct virtio_blk_config {
  48         /* The capacity (in 512-byte sectors). */
  49         uint64_t capacity;
  50         /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
  51         uint32_t size_max;
  52         /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
  53         uint32_t seg_max;
  54         /* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */
  55         struct virtio_blk_geometry {
  56                 uint16_t cylinders;
  57                 uint8_t heads;
  58                 uint8_t sectors;
  59         } geometry;
  60
  61         /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
  62         uint32_t blk_size;
  63 } _PACKED;
  64
  65 /*
  66  * Command types
  67  *
  68  * Usage is a bit tricky as some bits are used as flags and some are not.
  69  *
  70  * Rules:
  71  *   VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
  72  *   VIRTIO_BLK_T_BARRIER.  VIRTIO_BLK_T_FLUSH is a command of its own
  73  *   and may not be combined with any of the other flags.
  74  */
  75
  76 /* These two define direction. */
  77 #define VIRTIO_BLK_T_IN         0
  78 #define VIRTIO_BLK_T_OUT        1
  79
  80 /* This bit says it's a scsi command, not an actual read or write. */
  81 #define VIRTIO_BLK_T_SCSI_CMD   2
  82
  83 /* Cache flush command */
  84 #define VIRTIO_BLK_T_FLUSH      4
  85
  86 /* Get device ID command */
  87 #define VIRTIO_BLK_T_GET_ID     8
  88
  89 /* Barrier before this op. */
  90 #define VIRTIO_BLK_T_BARRIER    0x80000000
  91
  92 /* ID string length */
  93 #define VIRTIO_BLK_ID_BYTES     20
  94
  95 /* This is the first element of the read scatter-gather list. */
  96 struct virtio_blk_outhdr {
  97         /* VIRTIO_BLK_T* */
  98         uint32_t type;
  99         /* io priority. */
 100         uint32_t ioprio;
 101         /* Sector (ie. 512 byte offset) */
 102         uint64_t sector;
 103 };
 104
 105 struct virtio_scsi_inhdr {
 106         uint32_t errors;
 107         uint32_t data_len;
 108         uint32_t sense_len;
 109         uint32_t residual;
 110 };
 111
 112 /* And this is the final byte of the write scatter-gather list. */
 113 #define VIRTIO_BLK_S_OK         0
 114 #define VIRTIO_BLK_S_IOERR      1
 115 #define VIRTIO_BLK_S_UNSUPP     2
 116
 117 #endif /* _VIRTIO_BLK_H */