| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/drivers/acorn/scsi/msgqueue.h |
| 3 | * |
| 4 | * Copyright (C) 1997 Russell King |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | * |
| 10 | * message queue handling |
| 11 | */ |
| 12 | #ifndef MSGQUEUE_H |
| 13 | #define MSGQUEUE_H |
| 14 | |
| 15 | struct message { |
| 16 | char msg[8]; |
| 17 | int length; |
| 18 | int fifo; |
| 19 | }; |
| 20 | |
| 21 | struct msgqueue_entry { |
| 22 | struct message msg; |
| 23 | struct msgqueue_entry *next; |
| 24 | }; |
| 25 | |
| 26 | #define NR_MESSAGES 4 |
| 27 | |
| 28 | typedef struct { |
| 29 | struct msgqueue_entry *qe; |
| 30 | struct msgqueue_entry *free; |
| 31 | struct msgqueue_entry entries[NR_MESSAGES]; |
| 32 | } MsgQueue_t; |
| 33 | |
| 34 | /* |
| 35 | * Function: void msgqueue_initialise(MsgQueue_t *msgq) |
| 36 | * Purpose : initialise a message queue |
| 37 | * Params : msgq - queue to initialise |
| 38 | */ |
| 39 | extern void msgqueue_initialise(MsgQueue_t *msgq); |
| 40 | |
| 41 | /* |
| 42 | * Function: void msgqueue_free(MsgQueue_t *msgq) |
| 43 | * Purpose : free a queue |
| 44 | * Params : msgq - queue to free |
| 45 | */ |
| 46 | extern void msgqueue_free(MsgQueue_t *msgq); |
| 47 | |
| 48 | /* |
| 49 | * Function: int msgqueue_msglength(MsgQueue_t *msgq) |
| 50 | * Purpose : calculate the total length of all messages on the message queue |
| 51 | * Params : msgq - queue to examine |
| 52 | * Returns : number of bytes of messages in queue |
| 53 | */ |
| 54 | extern int msgqueue_msglength(MsgQueue_t *msgq); |
| 55 | |
| 56 | /* |
| 57 | * Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno) |
| 58 | * Purpose : return a message & its length |
| 59 | * Params : msgq - queue to obtain message from |
| 60 | * : msgno - message number |
| 61 | * Returns : pointer to message string, or NULL |
| 62 | */ |
| 63 | extern struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno); |
| 64 | |
| 65 | /* |
| 66 | * Function: int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...) |
| 67 | * Purpose : add a message onto a message queue |
| 68 | * Params : msgq - queue to add message on |
| 69 | * length - length of message |
| 70 | * ... - message bytes |
| 71 | * Returns : != 0 if successful |
| 72 | */ |
| 73 | extern int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...); |
| 74 | |
| 75 | /* |
| 76 | * Function: void msgqueue_flush(MsgQueue_t *msgq) |
| 77 | * Purpose : flush all messages from message queue |
| 78 | * Params : msgq - queue to flush |
| 79 | */ |
| 80 | extern void msgqueue_flush(MsgQueue_t *msgq); |
| 81 | |
| 82 | #endif |