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