1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2 | /* |
3 | * linux/drivers/acorn/scsi/msgqueue.h |
4 | * |
5 | * Copyright (C) 1997 Russell King |
6 | * |
7 | * message queue handling |
8 | */ |
9 | #ifndef MSGQUEUE_H |
10 | #define MSGQUEUE_H |
11 | |
12 | struct message { |
13 | char msg[8]; |
14 | int length; |
15 | int fifo; |
16 | }; |
17 | |
18 | struct msgqueue_entry { |
19 | struct message msg; |
20 | struct msgqueue_entry *next; |
21 | }; |
22 | |
23 | #define NR_MESSAGES 4 |
24 | |
25 | typedef struct { |
26 | struct msgqueue_entry *qe; |
27 | struct msgqueue_entry *free; |
28 | struct msgqueue_entry entries[NR_MESSAGES]; |
29 | } MsgQueue_t; |
30 | |
31 | /* |
32 | * Function: void msgqueue_initialise(MsgQueue_t *msgq) |
33 | * Purpose : initialise a message queue |
34 | * Params : msgq - queue to initialise |
35 | */ |
36 | extern void msgqueue_initialise(MsgQueue_t *msgq); |
37 | |
38 | /* |
39 | * Function: void msgqueue_free(MsgQueue_t *msgq) |
40 | * Purpose : free a queue |
41 | * Params : msgq - queue to free |
42 | */ |
43 | extern void msgqueue_free(MsgQueue_t *msgq); |
44 | |
45 | /* |
46 | * Function: int msgqueue_msglength(MsgQueue_t *msgq) |
47 | * Purpose : calculate the total length of all messages on the message queue |
48 | * Params : msgq - queue to examine |
49 | * Returns : number of bytes of messages in queue |
50 | */ |
51 | extern int msgqueue_msglength(MsgQueue_t *msgq); |
52 | |
53 | /* |
54 | * Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno) |
55 | * Purpose : return a message & its length |
56 | * Params : msgq - queue to obtain message from |
57 | * : msgno - message number |
58 | * Returns : pointer to message string, or NULL |
59 | */ |
60 | extern struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno); |
61 | |
62 | /* |
63 | * Function: int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...) |
64 | * Purpose : add a message onto a message queue |
65 | * Params : msgq - queue to add message on |
66 | * length - length of message |
67 | * ... - message bytes |
68 | * Returns : != 0 if successful |
69 | */ |
70 | extern int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...); |
71 | |
72 | /* |
73 | * Function: void msgqueue_flush(MsgQueue_t *msgq) |
74 | * Purpose : flush all messages from message queue |
75 | * Params : msgq - queue to flush |
76 | */ |
77 | extern void msgqueue_flush(MsgQueue_t *msgq); |
78 | |
79 | #endif |
80 | |