/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2002 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#ifndef _SYS_RMC_COMM_LPROTO_H
#define _SYS_RMC_COMM_LPROTO_H

#pragma ident   "%Z%%M% %I%     %E% SMI"

#ifdef  __cplusplus
extern "C" {
#endif

#define SYNC_CHAR       0x80
#define ESC_CHAR        0x81

/* Maximum message length */

#define DP_MAX_MSGLEN   1024

/*
 * Tunables.
 */

/* Number of times a transmitted message will be retried. */
#define TX_RETRIES      10

/* Amount of time between transmit retries in ms, currently 500ms. */
#define TX_RETRY_TIME   500L

/* minimum waiting time for a reply (milliseconds) */
#define DP_MIN_TIMEOUT  200L

/*
 * timeout (in ms) for (re)trying to establish the protocol data link
 */
#define DELAY_DP_SETUP          10
#define RETRY_DP_SETUP          5000

/*
 * Data protocol message structure.  Note that this is the in-memory
 * version; when a data protocol message is transmitted it goes
 * through a translation to assist the receiving side in determining
 * message boundaries robustly.
 */
typedef struct dp_header {

        uint8_t  pad;           /* This pad byte is never transmitted nor */
                                /* received, it is solely to make the */
                                /* structure elements line up in memory. */
        uint8_t  type;          /* The message type-see below for valid types */
        uint16_t length;        /* Length of the whole message. */
        uint8_t  txnum;         /* Sequence number of this message. */
        uint8_t  rxnum;         /* Highest sequence number received. */
                                /* (AKA piggy-backed acknowledgement). */
        uint16_t crc;           /* CRC-16 Checksum of header. */

} dp_header_t;

/*
 * Macros for dealing with sequence id's.
 */

/* Given a sequence id, calculate the next one. */
#define NEXT_SEQID(a)           (((a) + 1) % 0x100)

/* Given a sequence id, calculate the previous one. */
#define PREV_SEQID(a)           (((a) == 0) ? 0xff : (a)-1)

/* Do these sequence ID's follow each other? */
#define IS_NEXT_SEQID(a, b)     ((b) == NEXT_SEQID(a))

/* What to initialize sequence ID counters to. */
#define INITIAL_SEQID           0xFF

/*
 * Macros for interpreting message types.
 */
#define IS_NUMBERED_MSG(t)      (((t) & 0x80) == 0x00)
#define IS_UNNUMBERED_MSG(t)    (((t) & 0xC0) == 0x80)
#define IS_BOOT_MSG(t)          (((t) & 0xE0) == 0xC0)

/*
 * Un-numbered messages.
 */

#define DP_CTL_START            0x88

#define DP_CTL_STACK            0x89

#define DP_CTL_RESPOND          0x8A

#define DP_CTL_ACK              0x8B

#define DP_CTL_NAK              0x8C

#ifdef  __cplusplus
}
#endif

#endif  /* _SYS_RMC_COMM_LPROTO_H */