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#define TCMU_MAILBOX_FLAG_CAP_READ_LEN (1 << 1) /* Read data length */
48
49struct tcmu_mailbox {
50 __u16 version;
51 __u16 flags;
52 __u32 cmdr_off;
53 __u32 cmdr_size;
54
55 __u32 cmd_head;
56
57 /* Updated by user. On its own cacheline */
58 __u32 cmd_tail __attribute__((__aligned__(ALIGN_SIZE)));
59
60} __packed;
61
62enum tcmu_opcode {
63 TCMU_OP_PAD = 0,
64 TCMU_OP_CMD,
65};
66
67/*
68 * Only a few opcodes, and length is 8-byte aligned, so use low bits for opcode.
69 */
70struct tcmu_cmd_entry_hdr {
71 __u32 len_op;
72 __u16 cmd_id;
73 __u8 kflags;
74#define TCMU_UFLAG_UNKNOWN_OP 0x1
75#define TCMU_UFLAG_READ_LEN 0x2
76 __u8 uflags;
77
78} __packed;
79
80#define TCMU_OP_MASK 0x7
81
82static inline enum tcmu_opcode tcmu_hdr_get_op(__u32 len_op)
83{
84 return len_op & TCMU_OP_MASK;
85}
86
87static inline void tcmu_hdr_set_op(__u32 *len_op, enum tcmu_opcode op)
88{
89 *len_op &= ~TCMU_OP_MASK;
90 *len_op |= (op & TCMU_OP_MASK);
91}
92
93static inline __u32 tcmu_hdr_get_len(__u32 len_op)
94{
95 return len_op & ~TCMU_OP_MASK;
96}
97
98static inline void tcmu_hdr_set_len(__u32 *len_op, __u32 len)
99{
100 *len_op &= TCMU_OP_MASK;
101 *len_op |= len;
102}
103
104/* Currently the same as SCSI_SENSE_BUFFERSIZE */
105#define TCMU_SENSE_BUFFERSIZE 96
106
107struct tcmu_cmd_entry {
108 struct tcmu_cmd_entry_hdr hdr;
109
110 union {
111 struct {
112 __u32 iov_cnt;
113 __u32 iov_bidi_cnt;
114 __u32 iov_dif_cnt;
115 __u64 cdb_off;
116 __u64 __pad1;
117 __u64 __pad2;
118 struct iovec iov[0];
119 } req;
120 struct {
121 __u8 scsi_status;
122 __u8 __pad1;
123 __u16 __pad2;
124 __u32 read_len;
125 char sense_buffer[TCMU_SENSE_BUFFERSIZE];
126 } rsp;
127 };
128
129} __packed;
130
131#define TCMU_OP_ALIGN_SIZE sizeof(__u64)
132
133enum tcmu_genl_cmd {
134 TCMU_CMD_UNSPEC,
135 TCMU_CMD_ADDED_DEVICE,
136 TCMU_CMD_REMOVED_DEVICE,
137 TCMU_CMD_RECONFIG_DEVICE,
138 TCMU_CMD_ADDED_DEVICE_DONE,
139 TCMU_CMD_REMOVED_DEVICE_DONE,
140 TCMU_CMD_RECONFIG_DEVICE_DONE,
141 TCMU_CMD_SET_FEATURES,
142 __TCMU_CMD_MAX,
143};
144#define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)
145
146enum tcmu_genl_attr {
147 TCMU_ATTR_UNSPEC,
148 TCMU_ATTR_DEVICE,
149 TCMU_ATTR_MINOR,
150 TCMU_ATTR_PAD,
151 TCMU_ATTR_DEV_CFG,
152 TCMU_ATTR_DEV_SIZE,
153 TCMU_ATTR_WRITECACHE,
154 TCMU_ATTR_CMD_STATUS,
155 TCMU_ATTR_DEVICE_ID,
156 TCMU_ATTR_SUPP_KERN_CMD_REPLY,
157 __TCMU_ATTR_MAX,
158};
159#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
160
161#endif
162