Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2#ifndef __TARGET_CORE_USER_H
3#define __TARGET_CORE_USER_H
4
5/* This header will be used by application too */
6
7#include <linux/types.h>
8#include <linux/uio.h>
9
10#define TCMU_VERSION "2.0"
11
12/*
13 * Ring Design
14 * -----------
15 *
16 * The mmaped area is divided into three parts:
17 * 1) The mailbox (struct tcmu_mailbox, below)
18 * 2) The command ring
19 * 3) Everything beyond the command ring (data)
20 *
21 * The mailbox tells userspace the offset of the command ring from the
22 * start of the shared memory region, and how big the command ring is.
23 *
24 * The kernel passes SCSI commands to userspace by putting a struct
25 * tcmu_cmd_entry in the ring, updating mailbox->cmd_head, and poking
26 * userspace via uio's interrupt mechanism.
27 *
28 * tcmu_cmd_entry contains a header. If the header type is PAD,
29 * userspace should skip hdr->length bytes (mod cmdr_size) to find the
30 * next cmd_entry.
31 *
32 * Otherwise, the entry will contain offsets into the mmaped area that
33 * contain the cdb and data buffers -- the latter accessible via the
34 * iov array. iov addresses are also offsets into the shared area.
35 *
36 * When userspace is completed handling the command, set
37 * entry->rsp.scsi_status, fill in rsp.sense_buffer if appropriate,
38 * and also set mailbox->cmd_tail equal to the old cmd_tail plus
39 * hdr->length, mod cmdr_size. If cmd_tail doesn't equal cmd_head, it
40 * should process the next packet the same way, and so on.
41 */
42
43#define TCMU_MAILBOX_VERSION 2
44#define ALIGN_SIZE 64 /* Should be enough for most CPUs */
45#define TCMU_MAILBOX_FLAG_CAP_OOOC (1 << 0) /* Out-of-order completions */
46
47struct tcmu_mailbox {
48 __u16 version;
49 __u16 flags;
50 __u32 cmdr_off;
51 __u32 cmdr_size;
52
53 __u32 cmd_head;
54
55 /* Updated by user. On its own cacheline */
56 __u32 cmd_tail __attribute__((__aligned__(ALIGN_SIZE)));
57
58} __packed;
59
60enum tcmu_opcode {
61 TCMU_OP_PAD = 0,
62 TCMU_OP_CMD,
63};
64
65/*
66 * Only a few opcodes, and length is 8-byte aligned, so use low bits for opcode.
67 */
68struct tcmu_cmd_entry_hdr {
69 __u32 len_op;
70 __u16 cmd_id;
71 __u8 kflags;
72#define TCMU_UFLAG_UNKNOWN_OP 0x1
73 __u8 uflags;
74
75} __packed;
76
77#define TCMU_OP_MASK 0x7
78
79static inline enum tcmu_opcode tcmu_hdr_get_op(__u32 len_op)
80{
81 return len_op & TCMU_OP_MASK;
82}
83
84static inline void tcmu_hdr_set_op(__u32 *len_op, enum tcmu_opcode op)
85{
86 *len_op &= ~TCMU_OP_MASK;
87 *len_op |= (op & TCMU_OP_MASK);
88}
89
90static inline __u32 tcmu_hdr_get_len(__u32 len_op)
91{
92 return len_op & ~TCMU_OP_MASK;
93}
94
95static inline void tcmu_hdr_set_len(__u32 *len_op, __u32 len)
96{
97 *len_op &= TCMU_OP_MASK;
98 *len_op |= len;
99}
100
101/* Currently the same as SCSI_SENSE_BUFFERSIZE */
102#define TCMU_SENSE_BUFFERSIZE 96
103
104struct tcmu_cmd_entry {
105 struct tcmu_cmd_entry_hdr hdr;
106
107 union {
108 struct {
109 __u32 iov_cnt;
110 __u32 iov_bidi_cnt;
111 __u32 iov_dif_cnt;
112 __u64 cdb_off;
113 __u64 __pad1;
114 __u64 __pad2;
115 struct iovec iov[0];
116 } req;
117 struct {
118 __u8 scsi_status;
119 __u8 __pad1;
120 __u16 __pad2;
121 __u32 __pad3;
122 char sense_buffer[TCMU_SENSE_BUFFERSIZE];
123 } rsp;
124 };
125
126} __packed;
127
128#define TCMU_OP_ALIGN_SIZE sizeof(__u64)
129
130enum tcmu_genl_cmd {
131 TCMU_CMD_UNSPEC,
132 TCMU_CMD_ADDED_DEVICE,
133 TCMU_CMD_REMOVED_DEVICE,
134 TCMU_CMD_RECONFIG_DEVICE,
135 TCMU_CMD_ADDED_DEVICE_DONE,
136 TCMU_CMD_REMOVED_DEVICE_DONE,
137 TCMU_CMD_RECONFIG_DEVICE_DONE,
138 TCMU_CMD_SET_FEATURES,
139 __TCMU_CMD_MAX,
140};
141#define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)
142
143enum tcmu_genl_attr {
144 TCMU_ATTR_UNSPEC,
145 TCMU_ATTR_DEVICE,
146 TCMU_ATTR_MINOR,
147 TCMU_ATTR_PAD,
148 TCMU_ATTR_DEV_CFG,
149 TCMU_ATTR_DEV_SIZE,
150 TCMU_ATTR_WRITECACHE,
151 TCMU_ATTR_CMD_STATUS,
152 TCMU_ATTR_DEVICE_ID,
153 TCMU_ATTR_SUPP_KERN_CMD_REPLY,
154 __TCMU_ATTR_MAX,
155};
156#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
157
158#endif