aboutsummaryrefslogtreecommitdiffstats
path: root/include/uapi/linux/target_core_user.h
blob: af17b4154ef607acf4887627200a224e35404dcf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
#ifndef __TARGET_CORE_USER_H
#define __TARGET_CORE_USER_H

/* This header will be used by application too */

#include <linux/types.h>
#include <linux/uio.h>

#define TCMU_VERSION "2.0"

/*
 * Ring Design
 * -----------
 *
 * The mmaped area is divided into three parts:
 * 1) The mailbox (struct tcmu_mailbox, below)
 * 2) The command ring
 * 3) Everything beyond the command ring (data)
 *
 * The mailbox tells userspace the offset of the command ring from the
 * start of the shared memory region, and how big the command ring is.
 *
 * The kernel passes SCSI commands to userspace by putting a struct
 * tcmu_cmd_entry in the ring, updating mailbox->cmd_head, and poking
 * userspace via uio's interrupt mechanism.
 *
 * tcmu_cmd_entry contains a header. If the header type is PAD,
 * userspace should skip hdr->length bytes (mod cmdr_size) to find the
 * next cmd_entry.
 *
 * Otherwise, the entry will contain offsets into the mmaped area that
 * contain the cdb and data buffers -- the latter accessible via the
 * iov array. iov addresses are also offsets into the shared area.
 *
 * When userspace is completed handling the command, set
 * entry->rsp.scsi_status, fill in rsp.sense_buffer if appropriate,
 * and also set mailbox->cmd_tail equal to the old cmd_tail plus
 * hdr->length, mod cmdr_size. If cmd_tail doesn't equal cmd_head, it
 * should process the next packet the same way, and so on.
 */

#define TCMU_MAILBOX_VERSION 2
#define ALIGN_SIZE 64 /* Should be enough for most CPUs */
#define TCMU_MAILBOX_FLAG_CAP_OOOC (1 << 0) /* Out-of-order completions */

struct tcmu_mailbox {
	__u16 version;
	__u16 flags;
	__u32 cmdr_off;
	__u32 cmdr_size;

	__u32 cmd_head;

	/* Updated by user. On its own cacheline */
	__u32 cmd_tail __attribute__((__aligned__(ALIGN_SIZE)));

} __packed;

enum tcmu_opcode {
	TCMU_OP_PAD = 0,
	TCMU_OP_CMD,
};

/*
 * Only a few opcodes, and length is 8-byte aligned, so use low bits for opcode.
 */
struct tcmu_cmd_entry_hdr {
	__u32 len_op;
	__u16 cmd_id;
	__u8 kflags;
#define TCMU_UFLAG_UNKNOWN_OP 0x1
	__u8 uflags;

} __packed;

#define TCMU_OP_MASK 0x7

static inline enum tcmu_opcode tcmu_hdr_get_op(__u32 len_op)
{
	return len_op & TCMU_OP_MASK;
}

static inline void tcmu_hdr_set_op(__u32 *len_op, enum tcmu_opcode op)
{
	*len_op &= ~TCMU_OP_MASK;
	*len_op |= (op & TCMU_OP_MASK);
}

static inline __u32 tcmu_hdr_get_len(__u32 len_op)
{
	return len_op & ~TCMU_OP_MASK;
}

static inline void tcmu_hdr_set_len(__u32 *len_op, __u32 len)
{
	*len_op &= TCMU_OP_MASK;
	*len_op |= len;
}

/* Currently the same as SCSI_SENSE_BUFFERSIZE */
#define TCMU_SENSE_BUFFERSIZE 96

struct tcmu_cmd_entry {
	struct tcmu_cmd_entry_hdr hdr;

	union {
		struct {
			__u32 iov_cnt;
			__u32 iov_bidi_cnt;
			__u32 iov_dif_cnt;
			__u64 cdb_off;
			__u64 __pad1;
			__u64 __pad2;
			struct iovec iov[0];
		} req;
		struct {
			__u8 scsi_status;
			__u8 __pad1;
			__u16 __pad2;
			__u32 __pad3;
			char sense_buffer[TCMU_SENSE_BUFFERSIZE];
		} rsp;
	};

} __packed;

#define TCMU_OP_ALIGN_SIZE sizeof(__u64)

enum tcmu_genl_cmd {
	TCMU_CMD_UNSPEC,
	TCMU_CMD_ADDED_DEVICE,
	TCMU_CMD_REMOVED_DEVICE,
	__TCMU_CMD_MAX,
};
#define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)

enum tcmu_genl_attr {
	TCMU_ATTR_UNSPEC,
	TCMU_ATTR_DEVICE,
	TCMU_ATTR_MINOR,
	__TCMU_ATTR_MAX,
};
#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)

#endif

Privacy Policy