1/*	$NetBSD: sir.c,v 1.5 2008/04/28 20:23:51 martin Exp $	*/
2
3/*
4 * Copyright (c) 2001 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Lennart Augustsson (lennart@augustsson.net) and Tommy Bohlin
9 * (tommy@gatespace.com).
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33/*
34 * Framing originally written by Tommy Bohlin.
35 */
36
37#include <sys/cdefs.h>
38__KERNEL_RCSID(0, "$NetBSD: sir.c,v 1.5 2008/04/28 20:23:51 martin Exp $");
39
40#include <sys/param.h>
41#include <sys/conf.h>
42#include <sys/systm.h>
43
44#include <dev/ir/sir.h>
45
46/*
47 * CRC computation table
48 */
49const uint16_t irda_fcstab[] = {
50	0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
51	0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
52	0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
53	0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
54	0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
55	0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
56	0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
57	0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
58	0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
59	0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
60	0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
61	0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
62	0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
63	0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
64	0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
65	0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
66	0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
67	0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
68	0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
69	0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
70	0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
71	0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
72	0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
73	0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
74	0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
75	0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
76	0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
77	0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
78	0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
79	0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
80	0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
81	0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
82};
83
84#define MAX_IRDA_FRAME 5000	/* XXX what is it? */
85
86#define PUTC(c) if (p < end) *p++ = (c)
87#define PUTESC(c) \
88	if (c == SIR_BOF || c == SIR_EOF || c == SIR_CE) { \
89		PUTC(SIR_CE); \
90		PUTC(SIR_ESC_BIT^c); \
91	} else { \
92		PUTC(c); \
93	}
94
95#define CHUNK 512
96
97int
98irda_sir_frame(uint8_t *obuf, u_int maxlen, struct uio *uio, u_int ebofs)
99{
100	uint8_t ibuf[CHUNK];
101	uint8_t *p, *end, *cp;
102	size_t n;
103	int error;
104	int i;
105	int c;
106	uint16_t ofcs;
107
108	p = obuf;
109	end = p + maxlen;
110
111	for (i = 0; i < ebofs; i++)
112		PUTC(SIR_EXTRA_BOF);
113	PUTC(SIR_BOF);
114
115	ofcs = INITFCS;
116	while (uio->uio_resid > 0) {
117		n = uio->uio_resid;
118		if (n > CHUNK)
119			n = CHUNK;
120		error = uiomove(ibuf, n, uio);
121		if (error)
122			return (-error);
123
124		cp = ibuf;
125		while (n-- > 0) {
126			c = *cp++;
127			ofcs = updateFCS(ofcs, c);
128			PUTESC(c);
129		}
130	}
131
132	ofcs = ~ofcs;
133	c = ofcs & 0xff;
134	PUTESC(c);
135	c = (ofcs >> 8) & 0xff;
136	PUTESC(c);
137	PUTC(SIR_EOF);
138
139	if (p < end)
140		return (p - obuf);
141	else
142		return (-EINVAL);
143}
144
145void
146deframe_init(struct framestate *fstate, uint8_t *buf, size_t buflen)
147{
148
149	fstate->buffer = buf;
150	fstate->buflen = buflen;
151
152	deframe_clear(fstate);
153}
154
155void
156deframe_clear(struct framestate *fstate)
157{
158
159	fstate->bufindex = 0;
160	fstate->fsmstate = FSTATE_END_OF_FRAME;
161	fstate->escaped = 0;
162}
163
164enum frameresult
165deframe_process(struct framestate *fstate, uint8_t const **bptr, size_t *blen)
166{
167	uint8_t const *cptr;
168	size_t ibuflen, obufindex, obuflen;
169	enum framefsmstate fsmstate;
170	enum frameresult result;
171
172	cptr = *bptr;
173	fsmstate = fstate->fsmstate;
174	obufindex = fstate->bufindex;
175	obuflen = fstate->buflen;
176	ibuflen = *blen;
177
178	while (ibuflen-- > 0) {
179		uint8_t chr;
180
181		chr = *cptr++;
182
183		if (fstate->escaped) {
184			fstate->escaped = 0;
185			chr ^= SIR_ESC_BIT;
186		} else if (chr == SIR_CE) {
187			fstate->escaped = 1;
188			continue;
189		}
190
191		switch (fsmstate) {
192		case FSTATE_IN_DATA:
193			if (chr == SIR_EOF) {
194				fsmstate = FSTATE_IN_END;
195				fstate->state_index = 1;
196				goto state_in_end;
197			}
198			if (obufindex >= obuflen) {
199				result = FR_BUFFEROVERRUN;
200				fsmstate = FSTATE_END_OF_FRAME;
201				goto complete;
202			}
203			fstate->buffer[obufindex++] = chr;
204			break;
205
206		state_in_end:
207			/* FALLTHROUGH */
208
209		case FSTATE_IN_END:
210			if (--fstate->state_index == 0) {
211				uint32_t crc;
212				const size_t fcslen = 2;
213
214				fsmstate = FSTATE_END_OF_FRAME;
215
216				if (obufindex < fcslen) {
217					result = FR_FRAMEMALFORMED;
218					goto complete;
219				}
220
221				crc = crc_ccitt_16(INITFCS, fstate->buffer,
222				    obufindex);
223
224				/* Remove check bytes from buffer length */
225				obufindex -= fcslen;
226
227				if (crc == GOODFCS)
228					result = FR_FRAMEOK;
229				else
230					result = FR_FRAMEBADFCS;
231
232				goto complete;
233			}
234			break;
235
236		case FSTATE_END_OF_FRAME:
237			if (chr != SIR_BOF)
238				break;
239
240			fsmstate = FSTATE_START_OF_FRAME;
241			fstate->state_index = 1;
242			/* FALLTHROUGH */
243		case FSTATE_START_OF_FRAME:
244			if (--fstate->state_index == 0) {
245				fsmstate = FSTATE_IN_DATA;
246				obufindex = 0;
247			}
248			break;
249		}
250	}
251
252	result = (fsmstate == FSTATE_END_OF_FRAME) ? FR_IDLE : FR_INPROGRESS;
253
254 complete:
255	fstate->bufindex = obufindex;
256	fstate->fsmstate = fsmstate;
257	*blen = ibuflen;
258
259	return result;
260}
261
262uint32_t
263crc_ccitt_16(uint32_t crcinit, uint8_t const *buf, size_t blen)
264{
265
266	while (blen-- > 0) {
267		uint8_t chr;
268		chr = *buf++;
269		crcinit = updateFCS(crcinit, chr);
270	}
271	return crcinit;
272}
273