1#ifndef __TARGET_CORE_USER_H
2#define __TARGET_CORE_USER_H
3
4/* This header will be used by application too */
5
6#include <linux/types.h>
7#include <linux/uio.h>
8
9#define TCMU_VERSION "2.0"
10
11/*
12 * Ring Design
13 * -----------
14 *
15 * The mmaped area is divided into three parts:
16 * 1) The mailbox (struct tcmu_mailbox, below)
17 * 2) The command ring
18 * 3) Everything beyond the command ring (data)
19 *
20 * The mailbox tells userspace the offset of the command ring from the
21 * start of the shared memory region, and how big the command ring is.
22 *
23 * The kernel passes SCSI commands to userspace by putting a struct
24 * tcmu_cmd_entry in the ring, updating mailbox->cmd_head, and poking
25 * userspace via uio's interrupt mechanism.
26 *
27 * tcmu_cmd_entry contains a header. If the header type is PAD,
28 * userspace should skip hdr->length bytes (mod cmdr_size) to find the
29 * next cmd_entry.
30 *
31 * Otherwise, the entry will contain offsets into the mmaped area that
32 * contain the cdb and data buffers -- the latter accessible via the
33 * iov array. iov addresses are also offsets into the shared area.
34 *
35 * When userspace is completed handling the command, set
36 * entry->rsp.scsi_status, fill in rsp.sense_buffer if appropriate,
37 * and also set mailbox->cmd_tail equal to the old cmd_tail plus
38 * hdr->length, mod cmdr_size. If cmd_tail doesn't equal cmd_head, it
39 * should process the next packet the same way, and so on.
40 */
41
42#define TCMU_MAILBOX_VERSION 2
43#define ALIGN_SIZE 64 /* Should be enough for most CPUs */
44
45/* See https://gcc.gnu.org/onlinedocs/cpp/Stringification.html */
46#define xstr(s) str(s)
47#define str(s) #s
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	__u8 uflags;
76
77} __packed;
78
79#define TCMU_OP_MASK 0x7
80
81static inline enum tcmu_opcode tcmu_hdr_get_op(__u32 len_op)
82{
83	return len_op & TCMU_OP_MASK;
84}
85
86static inline void tcmu_hdr_set_op(__u32 *len_op, enum tcmu_opcode op)
87{
88	*len_op &= ~TCMU_OP_MASK;
89	*len_op |= (op & TCMU_OP_MASK);
90}
91
92static inline __u32 tcmu_hdr_get_len(__u32 len_op)
93{
94	return len_op & ~TCMU_OP_MASK;
95}
96
97static inline void tcmu_hdr_set_len(__u32 *len_op, __u32 len)
98{
99	*len_op &= TCMU_OP_MASK;
100	*len_op |= len;
101}
102
103/* Currently the same as SCSI_SENSE_BUFFERSIZE */
104#define TCMU_SENSE_BUFFERSIZE 96
105
106struct tcmu_cmd_entry {
107	struct tcmu_cmd_entry_hdr hdr;
108
109	union {
110		struct {
111			uint32_t iov_cnt;
112			uint32_t iov_bidi_cnt;
113			uint32_t iov_dif_cnt;
114			uint64_t cdb_off;
115			uint64_t __pad1;
116			uint64_t __pad2;
117			struct iovec iov[0];
118		} req;
119		struct {
120			uint8_t scsi_status;
121			uint8_t __pad1;
122			uint16_t __pad2;
123			uint32_t __pad3;
124			char sense_buffer[TCMU_SENSE_BUFFERSIZE];
125		} rsp;
126	};
127
128} __packed;
129
130#define TCMU_OP_ALIGN_SIZE sizeof(uint64_t)
131
132enum tcmu_genl_cmd {
133	TCMU_CMD_UNSPEC,
134	TCMU_CMD_ADDED_DEVICE,
135	TCMU_CMD_REMOVED_DEVICE,
136	__TCMU_CMD_MAX,
137};
138#define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)
139
140enum tcmu_genl_attr {
141	TCMU_ATTR_UNSPEC,
142	TCMU_ATTR_DEVICE,
143	TCMU_ATTR_MINOR,
144	__TCMU_ATTR_MAX,
145};
146#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
147
148#endif
149