xref: /minix3/minix/drivers/storage/virtio_blk/virtio_blk.h (revision 433d6423c39e34ec4b79c950597bb2d236f886be)
1*433d6423SLionel Sambuc #ifndef _LINUX_VIRTIO_BLK_H
2*433d6423SLionel Sambuc #define _LINUX_VIRTIO_BLK_H
3*433d6423SLionel Sambuc /* This header is BSD licensed so anyone can use the definitions to implement
4*433d6423SLionel Sambuc  * compatible drivers/servers.
5*433d6423SLionel Sambuc  *
6*433d6423SLionel Sambuc  * Redistribution and use in source and binary forms, with or without
7*433d6423SLionel Sambuc  * modification, are permitted provided that the following conditions
8*433d6423SLionel Sambuc  * are met:
9*433d6423SLionel Sambuc  * 1. Redistributions of source code must retain the above copyright
10*433d6423SLionel Sambuc  *    notice, this list of conditions and the following disclaimer.
11*433d6423SLionel Sambuc  * 2. Redistributions in binary form must reproduce the above copyright
12*433d6423SLionel Sambuc  *    notice, this list of conditions and the following disclaimer in the
13*433d6423SLionel Sambuc  *    documentation and/or other materials provided with the distribution.
14*433d6423SLionel Sambuc  * 3. Neither the name of IBM nor the names of its contributors
15*433d6423SLionel Sambuc  *    may be used to endorse or promote products derived from this software
16*433d6423SLionel Sambuc  *    without specific prior written permission.
17*433d6423SLionel Sambuc  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
18*433d6423SLionel Sambuc  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19*433d6423SLionel Sambuc  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20*433d6423SLionel Sambuc  * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
21*433d6423SLionel Sambuc  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22*433d6423SLionel Sambuc  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23*433d6423SLionel Sambuc  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24*433d6423SLionel Sambuc  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25*433d6423SLionel Sambuc  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26*433d6423SLionel Sambuc  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27*433d6423SLionel Sambuc  * SUCH DAMAGE. */
28*433d6423SLionel Sambuc #if 0
29*433d6423SLionel Sambuc #include <linux/types.h>
30*433d6423SLionel Sambuc #include <linux/virtio_ids.h>
31*433d6423SLionel Sambuc #include <linux/virtio_config.h>
32*433d6423SLionel Sambuc #endif
33*433d6423SLionel Sambuc 
34*433d6423SLionel Sambuc /* Feature bits */
35*433d6423SLionel Sambuc #define VIRTIO_BLK_F_BARRIER	0	/* Does host support barriers? */
36*433d6423SLionel Sambuc #define VIRTIO_BLK_F_SIZE_MAX	1	/* Indicates maximum segment size */
37*433d6423SLionel Sambuc #define VIRTIO_BLK_F_SEG_MAX	2	/* Indicates maximum # of segments */
38*433d6423SLionel Sambuc #define VIRTIO_BLK_F_GEOMETRY	4	/* Legacy geometry available  */
39*433d6423SLionel Sambuc #define VIRTIO_BLK_F_RO		5	/* Disk is read-only */
40*433d6423SLionel Sambuc #define VIRTIO_BLK_F_BLK_SIZE	6	/* Block size of disk is available*/
41*433d6423SLionel Sambuc #define VIRTIO_BLK_F_SCSI	7	/* Supports scsi command passthru */
42*433d6423SLionel Sambuc #define VIRTIO_BLK_F_FLUSH	9	/* Cache flush command support */
43*433d6423SLionel Sambuc #define VIRTIO_BLK_F_TOPOLOGY	10	/* Topology information is available */
44*433d6423SLionel Sambuc 
45*433d6423SLionel Sambuc #define VIRTIO_BLK_ID_BYTES	20	/* ID string length */
46*433d6423SLionel Sambuc 
47*433d6423SLionel Sambuc struct virtio_blk_config {
48*433d6423SLionel Sambuc 	/* The capacity (in 512-byte sectors). */
49*433d6423SLionel Sambuc 	u64_t capacity;
50*433d6423SLionel Sambuc 	/* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
51*433d6423SLionel Sambuc 	u32_t size_max;
52*433d6423SLionel Sambuc 	/* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
53*433d6423SLionel Sambuc 	u32_t seg_max;
54*433d6423SLionel Sambuc 	/* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */
55*433d6423SLionel Sambuc 	struct virtio_blk_geometry {
56*433d6423SLionel Sambuc 		u16_t cylinders;
57*433d6423SLionel Sambuc 		u8_t heads;
58*433d6423SLionel Sambuc 		u8_t sectors;
59*433d6423SLionel Sambuc 	} geometry;
60*433d6423SLionel Sambuc 
61*433d6423SLionel Sambuc 	/* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
62*433d6423SLionel Sambuc 	u32_t blk_size;
63*433d6423SLionel Sambuc 
64*433d6423SLionel Sambuc 	/* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY  */
65*433d6423SLionel Sambuc 	/* exponent for physical block per logical block. */
66*433d6423SLionel Sambuc 	u8_t physical_block_exp;
67*433d6423SLionel Sambuc 	/* alignment offset in logical blocks. */
68*433d6423SLionel Sambuc 	u8_t alignment_offset;
69*433d6423SLionel Sambuc 	/* minimum I/O size without performance penalty in logical blocks. */
70*433d6423SLionel Sambuc 	u16_t min_io_size;
71*433d6423SLionel Sambuc 	/* optimal sustained I/O size in logical blocks. */
72*433d6423SLionel Sambuc 	u32_t opt_io_size;
73*433d6423SLionel Sambuc 
74*433d6423SLionel Sambuc } __attribute__((packed));
75*433d6423SLionel Sambuc 
76*433d6423SLionel Sambuc /*
77*433d6423SLionel Sambuc  * Command types
78*433d6423SLionel Sambuc  *
79*433d6423SLionel Sambuc  * Usage is a bit tricky as some bits are used as flags and some are not.
80*433d6423SLionel Sambuc  *
81*433d6423SLionel Sambuc  * Rules:
82*433d6423SLionel Sambuc  *   VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
83*433d6423SLionel Sambuc  *   VIRTIO_BLK_T_BARRIER.  VIRTIO_BLK_T_FLUSH is a command of its own
84*433d6423SLionel Sambuc  *   and may not be combined with any of the other flags.
85*433d6423SLionel Sambuc  */
86*433d6423SLionel Sambuc 
87*433d6423SLionel Sambuc /* These two define direction. */
88*433d6423SLionel Sambuc #define VIRTIO_BLK_T_IN		0
89*433d6423SLionel Sambuc #define VIRTIO_BLK_T_OUT	1
90*433d6423SLionel Sambuc 
91*433d6423SLionel Sambuc /* This bit says it's a scsi command, not an actual read or write. */
92*433d6423SLionel Sambuc #define VIRTIO_BLK_T_SCSI_CMD	2
93*433d6423SLionel Sambuc 
94*433d6423SLionel Sambuc /* Cache flush command */
95*433d6423SLionel Sambuc #define VIRTIO_BLK_T_FLUSH	4
96*433d6423SLionel Sambuc 
97*433d6423SLionel Sambuc /* Get device ID command */
98*433d6423SLionel Sambuc #define VIRTIO_BLK_T_GET_ID    8
99*433d6423SLionel Sambuc 
100*433d6423SLionel Sambuc /* Barrier before this op. */
101*433d6423SLionel Sambuc #define VIRTIO_BLK_T_BARRIER	0x80000000
102*433d6423SLionel Sambuc 
103*433d6423SLionel Sambuc /* This is the first element of the read scatter-gather list. */
104*433d6423SLionel Sambuc struct virtio_blk_outhdr {
105*433d6423SLionel Sambuc 	/* VIRTIO_BLK_T* */
106*433d6423SLionel Sambuc 	u32_t type;
107*433d6423SLionel Sambuc 	/* io priority. */
108*433d6423SLionel Sambuc 	u32_t ioprio;
109*433d6423SLionel Sambuc 	/* Sector (ie. 512 byte offset) */
110*433d6423SLionel Sambuc 	u64_t sector;
111*433d6423SLionel Sambuc };
112*433d6423SLionel Sambuc 
113*433d6423SLionel Sambuc struct virtio_scsi_inhdr {
114*433d6423SLionel Sambuc 	u32_t errors;
115*433d6423SLionel Sambuc 	u32_t data_len;
116*433d6423SLionel Sambuc 	u32_t sense_len;
117*433d6423SLionel Sambuc 	u32_t residual;
118*433d6423SLionel Sambuc };
119*433d6423SLionel Sambuc 
120*433d6423SLionel Sambuc /* And this is the final byte of the write scatter-gather list. */
121*433d6423SLionel Sambuc #define VIRTIO_BLK_S_OK		0
122*433d6423SLionel Sambuc #define VIRTIO_BLK_S_IOERR	1
123*433d6423SLionel Sambuc #define VIRTIO_BLK_S_UNSUPP	2
124*433d6423SLionel Sambuc #endif /* _LINUX_VIRTIO_BLK_H */
125