a586d4f601
Previously we used a type/len pair within the config space, but this seems overkill. We now simply define a structure which represents the layout in the config space: the config space can now only be extended at the end. The main driver-visible changes: 1) We indicate what fields are present with an explicit feature bit. 2) Virtqueues are explicitly numbered, and not in the config space. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
56 lines
1.4 KiB
C
56 lines
1.4 KiB
C
#ifndef _LINUX_VIRTIO_BLK_H
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#define _LINUX_VIRTIO_BLK_H
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#include <linux/virtio_config.h>
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/* The ID for virtio_block */
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#define VIRTIO_ID_BLOCK 2
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/* Feature bits */
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#define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */
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#define VIRTIO_BLK_F_SIZE_MAX 1 /* Indicates maximum segment size */
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#define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */
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struct virtio_blk_config
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{
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/* The capacity (in 512-byte sectors). */
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__le64 capacity;
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/* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
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__le32 size_max;
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/* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
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__le32 seg_max;
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} __attribute__((packed));
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/* These two define direction. */
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#define VIRTIO_BLK_T_IN 0
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#define VIRTIO_BLK_T_OUT 1
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/* This bit says it's a scsi command, not an actual read or write. */
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#define VIRTIO_BLK_T_SCSI_CMD 2
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/* Barrier before this op. */
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#define VIRTIO_BLK_T_BARRIER 0x80000000
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/* This is the first element of the read scatter-gather list. */
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struct virtio_blk_outhdr
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{
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/* VIRTIO_BLK_T* */
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__u32 type;
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/* io priority. */
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__u32 ioprio;
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/* Sector (ie. 512 byte offset) */
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__u64 sector;
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/* Where to put reply. */
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__u64 id;
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};
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#define VIRTIO_BLK_S_OK 0
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#define VIRTIO_BLK_S_IOERR 1
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#define VIRTIO_BLK_S_UNSUPP 2
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/* This is the first element of the write scatter-gather list */
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struct virtio_blk_inhdr
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{
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unsigned char status;
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};
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#endif /* _LINUX_VIRTIO_BLK_H */
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