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Committer: Michael Beasley <mike@snafu.setup>
[mikesnafu-overlay.git] / drivers / isdn / i4l / isdn_v110.c
blobc5d02b6aafabb614ed731ff9318b9e7281ec93a2
1 /* $Id: isdn_v110.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $
2 *
3 * Linux ISDN subsystem, V.110 related functions (linklevel).
4 *
5 * Copyright by Thomas Pfeiffer (pfeiffer@pds.de)
6 *
7 * This software may be used and distributed according to the terms
8 * of the GNU General Public License, incorporated herein by reference.
9 *
10 */
11
12 #include <linux/string.h>
13 #include <linux/kernel.h>
14 #include <linux/slab.h>
15 #include <linux/mm.h>
16 #include <linux/delay.h>
17
18 #include <linux/isdn.h>
19 #include "isdn_v110.h"
20
21 #undef ISDN_V110_DEBUG
22
23 char *isdn_v110_revision = "$Revision: 1.1.2.2 $";
24
25 #define V110_38400 255
26 #define V110_19200 15
27 #define V110_9600 3
28
29 /*
30 * The following data are precoded matrices, online and offline matrix
31 * for 9600, 19200 und 38400, respectively
32 */
33 static unsigned char V110_OnMatrix_9600[] =
34 {0xfc, 0xfc, 0xfc, 0xfc, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff,
35 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd,
36 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff,
37 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd};
38
39 static unsigned char V110_OffMatrix_9600[] =
40 {0xfc, 0xfc, 0xfc, 0xfc, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
41 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
42 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
43 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
44
45 static unsigned char V110_OnMatrix_19200[] =
46 {0xf0, 0xf0, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7,
47 0xfd, 0xff, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7};
48
49 static unsigned char V110_OffMatrix_19200[] =
50 {0xf0, 0xf0, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
51 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
52
53 static unsigned char V110_OnMatrix_38400[] =
54 {0x00, 0x7f, 0x7f, 0x7f, 0x7f, 0xfd, 0x7f, 0x7f, 0x7f, 0x7f};
55
56 static unsigned char V110_OffMatrix_38400[] =
57 {0x00, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xff};
58
59 /*
60 * FlipBits reorders sequences of keylen bits in one byte.
61 * E.g. source order 7654321 will be converted to 45670123 when keylen = 4,
62 * and to 67452301 when keylen = 2. This is necessary because ordering on
63 * the isdn line is the other way.
64 */
65 static inline unsigned char
66 FlipBits(unsigned char c, int keylen)
67 {
68 unsigned char b = c;
69 unsigned char bit = 128;
70 int i;
71 int j;
72 int hunks = (8 / keylen);
73
74 c = 0;
75 for (i = 0; i < hunks; i++) {
76 for (j = 0; j < keylen; j++) {
77 if (b & (bit >> j))
78 c |= bit >> (keylen - j - 1);
79 }
80 bit >>= keylen;
81 }
82 return c;
83 }
84
85
86 /* isdn_v110_open allocates and initializes private V.110 data
87 * structures and returns a pointer to these.
88 */
89 static isdn_v110_stream *
90 isdn_v110_open(unsigned char key, int hdrlen, int maxsize)
91 {
92 int i;
93 isdn_v110_stream *v;
94
95 if ((v = kzalloc(sizeof(isdn_v110_stream), GFP_ATOMIC)) == NULL)
96 return NULL;
97 v->key = key;
98 v->nbits = 0;
99 for (i = 0; key & (1 << i); i++)
100 v->nbits++;
101
102 v->nbytes = 8 / v->nbits;
103 v->decodelen = 0;
104
105 switch (key) {
106 case V110_38400:
107 v->OnlineFrame = V110_OnMatrix_38400;
108 v->OfflineFrame = V110_OffMatrix_38400;
109 break;
110 case V110_19200:
111 v->OnlineFrame = V110_OnMatrix_19200;
112 v->OfflineFrame = V110_OffMatrix_19200;
113 break;
114 default:
115 v->OnlineFrame = V110_OnMatrix_9600;
116 v->OfflineFrame = V110_OffMatrix_9600;
117 break;
118 }
119 v->framelen = v->nbytes * 10;
120 v->SyncInit = 5;
121 v->introducer = 0;
122 v->dbit = 1;
123 v->b = 0;
124 v->skbres = hdrlen;
125 v->maxsize = maxsize - hdrlen;
126 if ((v->encodebuf = kmalloc(maxsize, GFP_ATOMIC)) == NULL) {
127 kfree(v);
128 return NULL;
129 }
130 return v;
131 }
132
133 /* isdn_v110_close frees private V.110 data structures */
134 void
135 isdn_v110_close(isdn_v110_stream * v)
136 {
137 if (v == NULL)
138 return;
139 #ifdef ISDN_V110_DEBUG
140 printk(KERN_DEBUG "v110 close\n");
141 #endif
142 kfree(v->encodebuf);
143 kfree(v);
144 }
145
146
147 /*
148 * ValidHeaderBytes return the number of valid bytes in v->decodebuf
149 */
150 static int
151 ValidHeaderBytes(isdn_v110_stream * v)
152 {
153 int i;
154 for (i = 0; (i < v->decodelen) && (i < v->nbytes); i++)
155 if ((v->decodebuf[i] & v->key) != 0)
156 break;
157 return i;
158 }
159
160 /*
161 * SyncHeader moves the decodebuf ptr to the next valid header
162 */
163 static void
164 SyncHeader(isdn_v110_stream * v)
165 {
166 unsigned char *rbuf = v->decodebuf;
167 int len = v->decodelen;
168
169 if (len == 0)
170 return;
171 for (rbuf++, len--; len > 0; len--, rbuf++) /* such den SyncHeader in buf ! */
172 if ((*rbuf & v->key) == 0) /* erstes byte gefunden ? */
173 break; /* jupp! */
174 if (len)
175 memcpy(v->decodebuf, rbuf, len);
176
177 v->decodelen = len;
178 #ifdef ISDN_V110_DEBUG
179 printk(KERN_DEBUG "isdn_v110: Header resync\n");
180 #endif
181 }
182
183 /* DecodeMatrix takes n (n>=1) matrices (v110 frames, 10 bytes) where
184 len is the number of matrix-lines. len must be a multiple of 10, i.e.
185 only complete matices must be given.
186 From these, netto data is extracted and returned in buf. The return-value
187 is the bytecount of the decoded data.
188 */
189 static int
190 DecodeMatrix(isdn_v110_stream * v, unsigned char *m, int len, unsigned char *buf)
191 {
192 int line = 0;
193 int buflen = 0;
194 int mbit = 64;
195 int introducer = v->introducer;
196 int dbit = v->dbit;
197 unsigned char b = v->b;
198
199 while (line < len) { /* Are we done with all lines of the matrix? */
200 if ((line % 10) == 0) { /* the 0. line of the matrix is always 0 ! */
201 if (m[line] != 0x00) { /* not 0 ? -> error! */
202 #ifdef ISDN_V110_DEBUG
203 printk(KERN_DEBUG "isdn_v110: DecodeMatrix, V110 Bad Header\n");
204 /* returning now is not the right thing, though :-( */
205 #endif
206 }
207 line++; /* next line of matrix */
208 continue;
209 } else if ((line % 10) == 5) { /* in line 5 there's only e-bits ! */
210 if ((m[line] & 0x70) != 0x30) { /* 011 has to be at the beginning! */
211 #ifdef ISDN_V110_DEBUG
212 printk(KERN_DEBUG "isdn_v110: DecodeMatrix, V110 Bad 5th line\n");
213 /* returning now is not the right thing, though :-( */
214 #endif
215 }
216 line++; /* next line */
217 continue;
218 } else if (!introducer) { /* every byte starts with 10 (stopbit, startbit) */
219 introducer = (m[line] & mbit) ? 0 : 1; /* current bit of the matrix */
220 next_byte:
221 if (mbit > 2) { /* was it the last bit in this line ? */
222 mbit >>= 1; /* no -> take next */
223 continue;
224 } /* otherwise start with leftmost bit in the next line */
225 mbit = 64;
226 line++;
227 continue;
228 } else { /* otherwise we need to set a data bit */
229 if (m[line] & mbit) /* was that bit set in the matrix ? */
230 b |= dbit; /* yes -> set it in the data byte */
231 else
232 b &= dbit - 1; /* no -> clear it in the data byte */
233 if (dbit < 128) /* is that data byte done ? */
234 dbit <<= 1; /* no, got the next bit */
235 else { /* data byte is done */
236 buf[buflen++] = b; /* copy byte into the output buffer */
237 introducer = b = 0; /* init of the intro sequence and of the data byte */
238 dbit = 1; /* next we look for the 0th bit */
239 }
240 goto next_byte; /* look for next bit in the matrix */
241 }
242 }
243 v->introducer = introducer;
244 v->dbit = dbit;
245 v->b = b;
246 return buflen; /* return number of bytes in the output buffer */
247 }
248
249 /*
250 * DecodeStream receives V.110 coded data from the input stream. It recovers the
251 * original frames.
252 * The input stream doesn't need to be framed
253 */
254 struct sk_buff *
255 isdn_v110_decode(isdn_v110_stream * v, struct sk_buff *skb)
256 {
257 int i;
258 int j;
259 int len;
260 unsigned char *v110_buf;
261 unsigned char *rbuf;
262
263 if (!skb) {
264 printk(KERN_WARNING "isdn_v110_decode called with NULL skb!\n");
265 return NULL;
266 }
267 rbuf = skb->data;
268 len = skb->len;
269 if (v == NULL) {
270 /* invalid handle, no chance to proceed */
271 printk(KERN_WARNING "isdn_v110_decode called with NULL stream!\n");
272 dev_kfree_skb(skb);
273 return NULL;
274 }
275 if (v->decodelen == 0) /* cache empty? */
276 for (; len > 0; len--, rbuf++) /* scan for SyncHeader in buf */
277 if ((*rbuf & v->key) == 0)
278 break; /* found first byte */
279 if (len == 0) {
280 dev_kfree_skb(skb);
281 return NULL;
282 }
283 /* copy new data to decode-buffer */
284 memcpy(&(v->decodebuf[v->decodelen]), rbuf, len);
285 v->decodelen += len;
286 ReSync:
287 if (v->decodelen < v->nbytes) { /* got a new header ? */
288 dev_kfree_skb(skb);
289 return NULL; /* no, try later */
290 }
291 if (ValidHeaderBytes(v) != v->nbytes) { /* is that a valid header? */
292 SyncHeader(v); /* no -> look for header */
293 goto ReSync;
294 }
295 len = (v->decodelen - (v->decodelen % (10 * v->nbytes))) / v->nbytes;
296 if ((v110_buf = kmalloc(len, GFP_ATOMIC)) == NULL) {
297 printk(KERN_WARNING "isdn_v110_decode: Couldn't allocate v110_buf\n");
298 dev_kfree_skb(skb);
299 return NULL;
300 }
301 for (i = 0; i < len; i++) {
302 v110_buf[i] = 0;
303 for (j = 0; j < v->nbytes; j++)
304 v110_buf[i] |= (v->decodebuf[(i * v->nbytes) + j] & v->key) << (8 - ((j + 1) * v->nbits));
305 v110_buf[i] = FlipBits(v110_buf[i], v->nbits);
306 }
307 v->decodelen = (v->decodelen % (10 * v->nbytes));
308 memcpy(v->decodebuf, &(v->decodebuf[len * v->nbytes]), v->decodelen);
309
310 skb_trim(skb, DecodeMatrix(v, v110_buf, len, skb->data));
311 kfree(v110_buf);
312 if (skb->len)
313 return skb;
314 else {
315 kfree_skb(skb);
316 return NULL;
317 }
318 }
319
320 /* EncodeMatrix takes input data in buf, len is the bytecount.
321 Data is encoded into v110 frames in m. Return value is the number of
322 matrix-lines generated.
323 */
324 static int
325 EncodeMatrix(unsigned char *buf, int len, unsigned char *m, int mlen)
326 {
327 int line = 0;
328 int i = 0;
329 int mbit = 128;
330 int dbit = 1;
331 int introducer = 3;
332 int ibit[] = {0, 1, 1};
333
334 while ((i < len) && (line < mlen)) { /* while we still have input data */
335 switch (line % 10) { /* in which line of the matrix are we? */
336 case 0:
337 m[line++] = 0x00; /* line 0 is always 0 */
338 mbit = 128; /* go on with the 7th bit */
339 break;
340 case 5:
341 m[line++] = 0xbf; /* line 5 is always 10111111 */
342 mbit = 128; /* go on with the 7th bit */
343 break;
344 }
345 if (line >= mlen) {
346 printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!\n");
347 return line;
348 }
349 next_bit:
350 switch (mbit) { /* leftmost or rightmost bit ? */
351 case 1:
352 line++; /* rightmost -> go to next line */
353 if (line >= mlen) {
354 printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!\n");
355 return line;
356 }
357 case 128:
358 m[line] = 128; /* leftmost -> set byte to 1000000 */
359 mbit = 64; /* current bit in the matrix line */
360 continue;
361 }
362 if (introducer) { /* set 110 sequence ? */
363 introducer--; /* set on digit less */
364 m[line] |= ibit[introducer] ? mbit : 0; /* set corresponding bit */
365 mbit >>= 1; /* bit of matrix line >> 1 */
366 goto next_bit; /* and go on there */
367 } /* else push data bits into the matrix! */
368 m[line] |= (buf[i] & dbit) ? mbit : 0; /* set data bit in matrix */
369 if (dbit == 128) { /* was it the last one? */
370 dbit = 1; /* then go on with first bit of */
371 i++; /* next byte in input buffer */
372 if (i < len) /* input buffer done ? */
373 introducer = 3; /* no, write introducer 110 */
374 else { /* input buffer done ! */
375 m[line] |= (mbit - 1) & 0xfe; /* set remaining bits in line to 1 */
376 break;
377 }
378 } else /* not the last data bit */
379 dbit <<= 1; /* then go to next data bit */
380 mbit >>= 1; /* go to next bit of matrix */
381 goto next_bit;
382
383 }
384 /* if necessary, generate remaining lines of the matrix... */
385 if ((line) && ((line + 10) < mlen))
386 switch (++line % 10) {
387 case 1:
388 m[line++] = 0xfe;
389 case 2:
390 m[line++] = 0xfe;
391 case 3:
392 m[line++] = 0xfe;
393 case 4:
394 m[line++] = 0xfe;
395 case 5:
396 m[line++] = 0xbf;
397 case 6:
398 m[line++] = 0xfe;
399 case 7:
400 m[line++] = 0xfe;
401 case 8:
402 m[line++] = 0xfe;
403 case 9:
404 m[line++] = 0xfe;
405 }
406 return line; /* that's how many lines we have */
407 }
408
409 /*
410 * Build a sync frame.
411 */
412 static struct sk_buff *
413 isdn_v110_sync(isdn_v110_stream *v)
414 {
415 struct sk_buff *skb;
416
417 if (v == NULL) {
418 /* invalid handle, no chance to proceed */
419 printk(KERN_WARNING "isdn_v110_sync called with NULL stream!\n");
420 return NULL;
421 }
422 if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
423 skb_reserve(skb, v->skbres);
424 memcpy(skb_put(skb, v->framelen), v->OfflineFrame, v->framelen);
425 }
426 return skb;
427 }
428
429 /*
430 * Build an idle frame.
431 */
432 static struct sk_buff *
433 isdn_v110_idle(isdn_v110_stream *v)
434 {
435 struct sk_buff *skb;
436
437 if (v == NULL) {
438 /* invalid handle, no chance to proceed */
439 printk(KERN_WARNING "isdn_v110_sync called with NULL stream!\n");
440 return NULL;
441 }
442 if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
443 skb_reserve(skb, v->skbres);
444 memcpy(skb_put(skb, v->framelen), v->OnlineFrame, v->framelen);
445 }
446 return skb;
447 }
448
449 struct sk_buff *
450 isdn_v110_encode(isdn_v110_stream * v, struct sk_buff *skb)
451 {
452 int i;
453 int j;
454 int rlen;
455 int mlen;
456 int olen;
457 int size;
458 int sval1;
459 int sval2;
460 int nframes;
461 unsigned char *v110buf;
462 unsigned char *rbuf;
463 struct sk_buff *nskb;
464
465 if (v == NULL) {
466 /* invalid handle, no chance to proceed */
467 printk(KERN_WARNING "isdn_v110_encode called with NULL stream!\n");
468 return NULL;
469 }
470 if (!skb) {
471 /* invalid skb, no chance to proceed */
472 printk(KERN_WARNING "isdn_v110_encode called with NULL skb!\n");
473 return NULL;
474 }
475 rlen = skb->len;
476 nframes = (rlen + 3) / 4;
477 v110buf = v->encodebuf;
478 if ((nframes * 40) > v->maxsize) {
479 size = v->maxsize;
480 rlen = v->maxsize / 40;
481 } else
482 size = nframes * 40;
483 if (!(nskb = dev_alloc_skb(size + v->skbres + sizeof(int)))) {
484 printk(KERN_WARNING "isdn_v110_encode: Couldn't alloc skb\n");
485 return NULL;
486 }
487 skb_reserve(nskb, v->skbres + sizeof(int));
488 if (skb->len == 0) {
489 memcpy(skb_put(nskb, v->framelen), v->OnlineFrame, v->framelen);
490 *((int *)skb_push(nskb, sizeof(int))) = 0;
491 return nskb;
492 }
493 mlen = EncodeMatrix(skb->data, rlen, v110buf, size);
494 /* now distribute 2 or 4 bits each to the output stream! */
495 rbuf = skb_put(nskb, size);
496 olen = 0;
497 sval1 = 8 - v->nbits;
498 sval2 = v->key << sval1;
499 for (i = 0; i < mlen; i++) {
500 v110buf[i] = FlipBits(v110buf[i], v->nbits);
501 for (j = 0; j < v->nbytes; j++) {
502 if (size--)
503 *rbuf++ = ~v->key | (((v110buf[i] << (j * v->nbits)) & sval2) >> sval1);
504 else {
505 printk(KERN_WARNING "isdn_v110_encode: buffers full!\n");
506 goto buffer_full;
507 }
508 olen++;
509 }
510 }
511 buffer_full:
512 skb_trim(nskb, olen);
513 *((int *)skb_push(nskb, sizeof(int))) = rlen;
514 return nskb;
515 }
516
517 int
518 isdn_v110_stat_callback(int idx, isdn_ctrl *c)
519 {
520 isdn_v110_stream *v = NULL;
521 int i;
522 int ret = 0;
523
524 if (idx < 0)
525 return 0;
526 switch (c->command) {
527 case ISDN_STAT_BSENT:
528 /* Keep the send-queue of the driver filled
529 * with frames:
530 * If number of outstanding frames < 3,
531 * send down an Idle-Frame (or an Sync-Frame, if
532 * v->SyncInit != 0).
533 */
534 if (!(v = dev->v110[idx]))
535 return 0;
536 atomic_inc(&dev->v110use[idx]);
537 for (i=0; i * v->framelen < c->parm.length; i++) {
538 if (v->skbidle > 0) {
539 v->skbidle--;
540 ret = 1;
541 } else {
542 if (v->skbuser > 0)
543 v->skbuser--;
544 ret = 0;
545 }
546 }
547 for (i = v->skbuser + v->skbidle; i < 2; i++) {
548 struct sk_buff *skb;
549 if (v->SyncInit > 0)
550 skb = isdn_v110_sync(v);
551 else
552 skb = isdn_v110_idle(v);
553 if (skb) {
554 if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
555 dev_kfree_skb(skb);
556 break;
557 } else {
558 if (v->SyncInit)
559 v->SyncInit--;
560 v->skbidle++;
561 }
562 } else
563 break;
564 }
565 atomic_dec(&dev->v110use[idx]);
566 return ret;
567 case ISDN_STAT_DHUP:
568 case ISDN_STAT_BHUP:
569 while (1) {
570 atomic_inc(&dev->v110use[idx]);
571 if (atomic_dec_and_test(&dev->v110use[idx])) {
572 isdn_v110_close(dev->v110[idx]);
573 dev->v110[idx] = NULL;
574 break;
575 }
576 mdelay(1);
577 }
578 break;
579 case ISDN_STAT_BCONN:
580 if (dev->v110emu[idx] && (dev->v110[idx] == NULL)) {
581 int hdrlen = dev->drv[c->driver]->interface->hl_hdrlen;
582 int maxsize = dev->drv[c->driver]->interface->maxbufsize;
583 atomic_inc(&dev->v110use[idx]);
584 switch (dev->v110emu[idx]) {
585 case ISDN_PROTO_L2_V11096:
586 dev->v110[idx] = isdn_v110_open(V110_9600, hdrlen, maxsize);
587 break;
588 case ISDN_PROTO_L2_V11019:
589 dev->v110[idx] = isdn_v110_open(V110_19200, hdrlen, maxsize);
590 break;
591 case ISDN_PROTO_L2_V11038:
592 dev->v110[idx] = isdn_v110_open(V110_38400, hdrlen, maxsize);
593 break;
594 default:;
595 }
596 if ((v = dev->v110[idx])) {
597 while (v->SyncInit) {
598 struct sk_buff *skb = isdn_v110_sync(v);
599 if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
600 dev_kfree_skb(skb);
601 /* Unable to send, try later */
602 break;
603 }
604 v->SyncInit--;
605 v->skbidle++;
606 }
607 } else
608 printk(KERN_WARNING "isdn_v110: Couldn't open stream for chan %d\n", idx);
609 atomic_dec(&dev->v110use[idx]);
610 }
611 break;
612 default:
613 return 0;
614 }
615 return 0;
616 }
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