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 #ifndef __packed
10 #define __packed                        __attribute__((packed))
11 #endif
12 
13 #define TCMU_VERSION "1.0"
14 
15 /*
16  * Ring Design
17  * -----------
18  *
19  * The mmaped area is divided into three parts:
20  * 1) The mailbox (struct tcmu_mailbox, below)
21  * 2) The command ring
22  * 3) Everything beyond the command ring (data)
23  *
24  * The mailbox tells userspace the offset of the command ring from the
25  * start of the shared memory region, and how big the command ring is.
26  *
27  * The kernel passes SCSI commands to userspace by putting a struct
28  * tcmu_cmd_entry in the ring, updating mailbox->cmd_head, and poking
29  * userspace via uio's interrupt mechanism.
30  *
31  * tcmu_cmd_entry contains a header. If the header type is PAD,
32  * userspace should skip hdr->length bytes (mod cmdr_size) to find the
33  * next cmd_entry.
34  *
35  * Otherwise, the entry will contain offsets into the mmaped area that
36  * contain the cdb and data buffers -- the latter accessible via the
37  * iov array. iov addresses are also offsets into the shared area.
38  *
39  * When userspace is completed handling the command, set
40  * entry->rsp.scsi_status, fill in rsp.sense_buffer if appropriate,
41  * and also set mailbox->cmd_tail equal to the old cmd_tail plus
42  * hdr->length, mod cmdr_size. If cmd_tail doesn't equal cmd_head, it
43  * should process the next packet the same way, and so on.
44  */
45 
46 #define TCMU_MAILBOX_VERSION 1
47 #define ALIGN_SIZE 64 /* Should be enough for most CPUs */
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 } __packed;
73 
74 #define TCMU_OP_MASK 0x7
75 
76 static inline enum tcmu_opcode tcmu_hdr_get_op(struct tcmu_cmd_entry_hdr *hdr)
77 {
78 	return hdr->len_op & TCMU_OP_MASK;
79 }
80 
81 static inline void tcmu_hdr_set_op(struct tcmu_cmd_entry_hdr *hdr, enum tcmu_opcode op)
82 {
83 	hdr->len_op &= ~TCMU_OP_MASK;
84 	hdr->len_op |= (op & TCMU_OP_MASK);
85 }
86 
87 static inline __u32 tcmu_hdr_get_len(struct tcmu_cmd_entry_hdr *hdr)
88 {
89 	return hdr->len_op & ~TCMU_OP_MASK;
90 }
91 
92 static inline void tcmu_hdr_set_len(struct tcmu_cmd_entry_hdr *hdr, __u32 len)
93 {
94 	hdr->len_op &= TCMU_OP_MASK;
95 	hdr->len_op |= len;
96 }
97 
98 /* Currently the same as SCSI_SENSE_BUFFERSIZE */
99 #define TCMU_SENSE_BUFFERSIZE 96
100 
101 struct tcmu_cmd_entry {
102 	struct tcmu_cmd_entry_hdr hdr;
103 
104 	uint16_t cmd_id;
105 	uint16_t __pad1;
106 
107 	union {
108 		struct {
109 			uint64_t cdb_off;
110 			uint64_t iov_cnt;
111 			struct iovec iov[0];
112 		} req;
113 		struct {
114 			uint8_t scsi_status;
115 			uint8_t __pad1;
116 			uint16_t __pad2;
117 			uint32_t __pad3;
118 			char sense_buffer[TCMU_SENSE_BUFFERSIZE];
119 		} rsp;
120 	};
121 
122 } __packed;
123 
124 #define TCMU_OP_ALIGN_SIZE sizeof(uint64_t)
125 
126 enum tcmu_genl_cmd {
127 	TCMU_CMD_UNSPEC,
128 	TCMU_CMD_ADDED_DEVICE,
129 	TCMU_CMD_REMOVED_DEVICE,
130 	__TCMU_CMD_MAX,
131 };
132 #define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)
133 
134 enum tcmu_genl_attr {
135 	TCMU_ATTR_UNSPEC,
136 	TCMU_ATTR_DEVICE,
137 	TCMU_ATTR_MINOR,
138 	__TCMU_ATTR_MAX,
139 };
140 #define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
141 
142 #endif
143