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
49 struct 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
62 enum 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 */
70 struct 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
tcmu_hdr_get_op(__u32 len_op)81 static inline enum tcmu_opcode tcmu_hdr_get_op(__u32 len_op)
82 {
83 return len_op & TCMU_OP_MASK;
84 }
85
tcmu_hdr_set_op(__u32 * len_op,enum tcmu_opcode op)86 static 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
tcmu_hdr_get_len(__u32 len_op)92 static inline __u32 tcmu_hdr_get_len(__u32 len_op)
93 {
94 return len_op & ~TCMU_OP_MASK;
95 }
96
tcmu_hdr_set_len(__u32 * len_op,__u32 len)97 static 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
106 struct 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
132 enum 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
140 enum 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