xref: /src/sys/dev/ir/sir.c

/*	$NetBSD: sir.c,v 1.6 2013/05/27 16:23:20 kiyohara Exp $	*/

/*
 * Copyright (c) 2001 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Lennart Augustsson (lennart (at) augustsson.net) and Tommy Bohlin
 * (tommy (at) gatespace.com).
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Framing originally written by Tommy Bohlin.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sir.c,v 1.6 2013/05/27 16:23:20 kiyohara Exp $");

#include <sys/param.h>
#include <sys/conf.h>
#include <sys/systm.h>

#include <dev/ir/sir.h>

/*
 * CRC computation table
 */
const uint16_t irda_fcstab[] = {
	0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
	0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
	0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
	0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
	0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
	0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
	0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
	0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
	0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
	0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
	0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
	0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
	0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
	0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
	0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
	0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
	0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
	0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
	0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
	0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
	0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
	0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
	0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
	0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
	0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
	0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
	0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
	0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
	0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
	0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
	0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
	0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};

#define MAX_IRDA_FRAME 5000	/* XXX what is it? */

#define PUTC(c) if (p < end) *p++ = (c)
#define PUTESC(c) \
	if (c == SIR_BOF || c == SIR_EOF || c == SIR_CE) { \
		PUTC(SIR_CE); \
		PUTC(SIR_ESC_BIT^c); \
	} else { \
		PUTC(c); \
	}

#define CHUNK 512

int
irda_sir_frame(uint8_t *obuf, u_int maxlen, struct uio *uio, u_int ebofs)
{
	uint8_t ibuf[CHUNK];
	uint8_t *p, *end, *cp;
	size_t n;
	int error;
	int i;
	int c;
	uint16_t ofcs;

	p = obuf;
	end = p + maxlen;

	for (i = 0; i < ebofs; i++)
		PUTC(SIR_EXTRA_BOF);
	PUTC(SIR_BOF);

	ofcs = INITFCS;
	while (uio->uio_resid > 0) {
		n = uio->uio_resid;
		if (n > CHUNK)
			n = CHUNK;
		error = uiomove(ibuf, n, uio);
		if (error)
			return (-error);

		cp = ibuf;
		while (n-- > 0) {
			c = *cp++;
			ofcs = updateFCS(ofcs, c);
			PUTESC(c);
		}
	}

	ofcs = ~ofcs;
	c = ofcs & 0xff;
	PUTESC(c);
	c = (ofcs >> 8) & 0xff;
	PUTESC(c);
	PUTC(SIR_EOF);

	if (p < end)
		return (p - obuf);
	else
		return (-EINVAL);
}

void
deframe_init(struct framestate *fstate, uint8_t *buf, size_t buflen)
{

	fstate->buffer = buf;
	fstate->buflen = buflen;

	deframe_clear(fstate);
}

void
deframe_clear(struct framestate *fstate)
{

	fstate->bufindex = 0;
	fstate->fsmstate = FSTATE_END_OF_FRAME;
	fstate->escaped = 0;
}

enum frameresult
deframe_process(struct framestate *fstate, uint8_t const **bptr, size_t *blen)
{
	uint8_t const *cptr;
	size_t ibuflen, obufindex, obuflen;
	enum framefsmstate fsmstate;
	enum frameresult result;

	cptr = *bptr;
	fsmstate = fstate->fsmstate;
	obufindex = fstate->bufindex;
	obuflen = fstate->buflen;
	ibuflen = *blen;

	while (ibuflen-- > 0) {
		uint8_t chr;

		chr = *cptr++;

		if (fstate->escaped) {
			fstate->escaped = 0;
			chr ^= SIR_ESC_BIT;
		} else if (chr == SIR_CE) {
			fstate->escaped = 1;
			continue;
		}

		switch (fsmstate) {
		case FSTATE_IN_DATA:
			if (chr == SIR_EOF) {
				fsmstate = FSTATE_IN_END;
				fstate->state_index = 1;
				goto state_in_end;
			}
			if (obufindex >= obuflen) {
				result = FR_BUFFEROVERRUN;
				fsmstate = FSTATE_END_OF_FRAME;
				goto complete;
			}
			fstate->buffer[obufindex++] = chr;
			break;

		state_in_end:
			/* FALLTHROUGH */

		case FSTATE_IN_END:
			if (--fstate->state_index == 0) {
				uint32_t crc;
				const size_t fcslen = 2;

				fsmstate = FSTATE_END_OF_FRAME;

				if (obufindex < fcslen) {
					result = FR_FRAMEMALFORMED;
					goto complete;
				}

				crc = crc_ccitt_16(INITFCS, fstate->buffer,
				    obufindex);

				/* Remove check bytes from buffer length */
				obufindex -= fcslen;

				if (crc == GOODFCS)
					result = FR_FRAMEOK;
				else
					result = FR_FRAMEBADFCS;

				goto complete;
			}
			break;

		case FSTATE_END_OF_FRAME:
			if (chr != SIR_BOF)
				break;

			fsmstate = FSTATE_START_OF_FRAME;
			fstate->state_index = 1;
			/* FALLTHROUGH */
		case FSTATE_START_OF_FRAME:
			if (--fstate->state_index == 0) {
				fsmstate = FSTATE_IN_DATA;
				obufindex = 0;
			}
			break;
		}
	}

	result = (fsmstate == FSTATE_END_OF_FRAME) ? FR_IDLE : FR_INPROGRESS;

 complete:
	fstate->bufindex = obufindex;
	fstate->fsmstate = fsmstate;
	*blen = ibuflen;

	return result;
}

uint32_t
crc_ccitt_16(uint32_t crcinit, uint8_t const *buf, size_t blen)
{

	while (blen-- > 0) {
		uint8_t chr;
		chr = *buf++;
		crcinit = updateFCS(crcinit, chr);
	}
	return crcinit;
}