1/*
2 * Copyright (c) 2008 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28#include "kdp_serial.h"
29
30#define SKDP_START_CHAR 0xFA
31#define SKDP_END_CHAR 0xFB
32#define SKDP_ESC_CHAR 0xFE
33
34static enum {DS_WAITSTART, DS_READING, DS_ESCAPED} dsState;
35static unsigned char dsBuffer[1518];
36static int dsPos;
37
38void kdp_serialize_packet(unsigned char *packet, unsigned int len, void (*outFunc)(char))
39{
40	unsigned int index;
41	outFunc(SKDP_START_CHAR);
42	for (index = 0; index < len; index++) {
43		unsigned char byte = *packet++;
44		//need to escape '\n' because the kernel serial output turns it into a cr/lf
45		if(byte == SKDP_START_CHAR || byte == SKDP_END_CHAR || byte == SKDP_ESC_CHAR || byte == '\n')
46		{
47			outFunc(SKDP_ESC_CHAR);
48			byte = ~byte;
49		}
50		outFunc(byte);
51	}
52	outFunc(SKDP_END_CHAR);
53}
54
55unsigned char *kdp_unserialize_packet(unsigned char byte, unsigned int *len)
56{
57	switch(dsState)
58	{
59		case DS_WAITSTART:
60			if(byte == SKDP_START_CHAR)
61			{
62//				printf("got start char\n");
63				dsState = DS_READING;
64				dsPos = 0;
65				*len = SERIALIZE_READING;
66				return 0;
67			}
68			*len = SERIALIZE_WAIT_START;
69			break;
70		case DS_READING:
71			if(byte == SKDP_ESC_CHAR)
72			{
73				dsState = DS_ESCAPED;
74				*len = SERIALIZE_READING;
75				return 0;
76			}
77			if(byte == SKDP_START_CHAR)
78			{
79//				printf("unexpected start char, resetting\n");
80				dsPos = 0;
81				*len = SERIALIZE_READING;
82				return 0;
83			}
84			if(byte == SKDP_END_CHAR)
85			{
86				dsState = DS_WAITSTART;
87				*len = dsPos;
88				dsPos = 0;
89				return dsBuffer;
90			}
91			dsBuffer[dsPos++] = byte;
92			break;
93		case DS_ESCAPED:
94//			printf("unescaping %02x to %02x\n", byte, ~byte);
95			dsBuffer[dsPos++] = ~byte;
96			dsState = DS_READING;
97			*len = SERIALIZE_READING;
98			break;
99	}
100	if(dsPos == sizeof(dsBuffer)) //too much data...forget this packet
101	{
102		dsState = DS_WAITSTART;
103		dsPos = 0;
104		*len = SERIALIZE_WAIT_START;
105	}
106
107	return 0;
108}
109