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Commit	Line	Data
	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
	34	static enum {DS_WAITSTART, DS_READING, DS_ESCAPED} dsState;
	35	static unsigned char dsBuffer[1518];
	36	static int dsPos;
	37
	38	void 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
	55	unsigned 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	}