[PATCH] Generic HDLC WAN drivers - disable netif_carrier_off()
[linux-2.6] / drivers / isdn / i4l / isdn_v110.c
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 = kmalloc(sizeof(isdn_v110_stream), GFP_ATOMIC)) == NULL)
96                 return NULL;
97         memset(v, 0, sizeof(isdn_v110_stream));
98         v->key = key;
99         v->nbits = 0;
100         for (i = 0; key & (1 << i); i++)
101                 v->nbits++;
102
103         v->nbytes = 8 / v->nbits;
104         v->decodelen = 0;
105
106         switch (key) {
107                 case V110_38400:
108                         v->OnlineFrame = V110_OnMatrix_38400;
109                         v->OfflineFrame = V110_OffMatrix_38400;
110                         break;
111                 case V110_19200:
112                         v->OnlineFrame = V110_OnMatrix_19200;
113                         v->OfflineFrame = V110_OffMatrix_19200;
114                         break;
115                 default:
116                         v->OnlineFrame = V110_OnMatrix_9600;
117                         v->OfflineFrame = V110_OffMatrix_9600;
118                         break;
119         }
120         v->framelen = v->nbytes * 10;
121         v->SyncInit = 5;
122         v->introducer = 0;
123         v->dbit = 1;
124         v->b = 0;
125         v->skbres = hdrlen;
126         v->maxsize = maxsize - hdrlen;
127         if ((v->encodebuf = kmalloc(maxsize, GFP_ATOMIC)) == NULL) {
128                 kfree(v);
129                 return NULL;
130         }
131         return v;
132 }
133
134 /* isdn_v110_close frees private V.110 data structures */
135 void
136 isdn_v110_close(isdn_v110_stream * v)
137 {
138         if (v == NULL)
139                 return;
140 #ifdef ISDN_V110_DEBUG
141         printk(KERN_DEBUG "v110 close\n");
142 #endif
143         kfree(v->encodebuf);
144         kfree(v);
145 }
146
147
148 /* 
149  * ValidHeaderBytes return the number of valid bytes in v->decodebuf 
150  */
151 static int
152 ValidHeaderBytes(isdn_v110_stream * v)
153 {
154         int i;
155         for (i = 0; (i < v->decodelen) && (i < v->nbytes); i++)
156                 if ((v->decodebuf[i] & v->key) != 0)
157                         break;
158         return i;
159 }
160
161 /* 
162  * SyncHeader moves the decodebuf ptr to the next valid header 
163  */
164 static void
165 SyncHeader(isdn_v110_stream * v)
166 {
167         unsigned char *rbuf = v->decodebuf;
168         int len = v->decodelen;
169
170         if (len == 0)
171                 return;
172         for (rbuf++, len--; len > 0; len--, rbuf++)     /* such den SyncHeader in buf ! */
173                 if ((*rbuf & v->key) == 0)      /* erstes byte gefunden ?       */
174                         break;  /* jupp!                        */
175         if (len)
176                 memcpy(v->decodebuf, rbuf, len);
177
178         v->decodelen = len;
179 #ifdef ISDN_V110_DEBUG
180         printk(KERN_DEBUG "isdn_v110: Header resync\n");
181 #endif
182 }
183
184 /* DecodeMatrix takes n (n>=1) matrices (v110 frames, 10 bytes) where
185    len is the number of matrix-lines. len must be a multiple of 10, i.e.
186    only complete matices must be given.
187    From these, netto data is extracted and returned in buf. The return-value
188    is the bytecount of the decoded data.
189  */
190 static int
191 DecodeMatrix(isdn_v110_stream * v, unsigned char *m, int len, unsigned char *buf)
192 {
193         int line = 0;
194         int buflen = 0;
195         int mbit = 64;
196         int introducer = v->introducer;
197         int dbit = v->dbit;
198         unsigned char b = v->b;
199
200         while (line < len) {    /* Are we done with all lines of the matrix? */
201                 if ((line % 10) == 0) { /* the 0. line of the matrix is always 0 ! */
202                         if (m[line] != 0x00) {  /* not 0 ? -> error! */
203 #ifdef ISDN_V110_DEBUG
204                                 printk(KERN_DEBUG "isdn_v110: DecodeMatrix, V110 Bad Header\n");
205                                 /* returning now is not the right thing, though :-( */
206 #endif
207                         } 
208                         line++; /* next line of matrix */
209                         continue;
210                 } else if ((line % 10) == 5) {  /* in line 5 there's only e-bits ! */
211                         if ((m[line] & 0x70) != 0x30) { /* 011 has to be at the beginning! */
212 #ifdef ISDN_V110_DEBUG
213                                 printk(KERN_DEBUG "isdn_v110: DecodeMatrix, V110 Bad 5th line\n");
214                                 /* returning now is not the right thing, though :-( */
215 #endif
216                         }
217                         line++; /* next line */
218                         continue;
219                 } else if (!introducer) {       /* every byte starts with 10 (stopbit, startbit) */
220                         introducer = (m[line] & mbit) ? 0 : 1;  /* current bit of the matrix */
221                       next_byte:
222                         if (mbit > 2) { /* was it the last bit in this line ? */
223                                 mbit >>= 1;     /* no -> take next */
224                                 continue;
225                         }       /* otherwise start with leftmost bit in the next line */
226                         mbit = 64;
227                         line++;
228                         continue;
229                 } else {        /* otherwise we need to set a data bit */
230                         if (m[line] & mbit)     /* was that bit set in the matrix ? */
231                                 b |= dbit;      /* yes -> set it in the data byte */
232                         else
233                                 b &= dbit - 1;  /* no -> clear it in the data byte */
234                         if (dbit < 128) /* is that data byte done ? */
235                                 dbit <<= 1;     /* no, got the next bit */
236                         else {  /* data byte is done */
237                                 buf[buflen++] = b;      /* copy byte into the output buffer */
238                                 introducer = b = 0;     /* init of the intro sequence and of the data byte */
239                                 dbit = 1;       /* next we look for the 0th bit */
240                         }
241                         goto next_byte; /* look for next bit in the matrix */
242                 }
243         }
244         v->introducer = introducer;
245         v->dbit = dbit;
246         v->b = b;
247         return buflen;          /* return number of bytes in the output buffer */
248 }
249
250 /* 
251  * DecodeStream receives V.110 coded data from the input stream. It recovers the 
252  * original frames.
253  * The input stream doesn't need to be framed
254  */
255 struct sk_buff *
256 isdn_v110_decode(isdn_v110_stream * v, struct sk_buff *skb)
257 {
258         int i;
259         int j;
260         int len;
261         unsigned char *v110_buf;
262         unsigned char *rbuf;
263
264         if (!skb) {
265                 printk(KERN_WARNING "isdn_v110_decode called with NULL skb!\n");
266                 return NULL;
267         }
268         rbuf = skb->data;
269         len = skb->len;
270         if (v == NULL) {
271                 /* invalid handle, no chance to proceed */
272                 printk(KERN_WARNING "isdn_v110_decode called with NULL stream!\n");
273                 dev_kfree_skb(skb);
274                 return NULL;
275         }
276         if (v->decodelen == 0)  /* cache empty?               */
277                 for (; len > 0; len--, rbuf++)  /* scan for SyncHeader in buf */
278                         if ((*rbuf & v->key) == 0)
279                                 break;  /* found first byte           */
280         if (len == 0) {
281                 dev_kfree_skb(skb);
282                 return NULL;
283         }
284         /* copy new data to decode-buffer */
285         memcpy(&(v->decodebuf[v->decodelen]), rbuf, len);
286         v->decodelen += len;
287       ReSync:
288         if (v->decodelen < v->nbytes) { /* got a new header ? */
289                 dev_kfree_skb(skb);
290                 return NULL;    /* no, try later      */
291         }
292         if (ValidHeaderBytes(v) != v->nbytes) { /* is that a valid header? */
293                 SyncHeader(v);  /* no -> look for header */
294                 goto ReSync;
295         }
296         len = (v->decodelen - (v->decodelen % (10 * v->nbytes))) / v->nbytes;
297         if ((v110_buf = kmalloc(len, GFP_ATOMIC)) == NULL) {
298                 printk(KERN_WARNING "isdn_v110_decode: Couldn't allocate v110_buf\n");
299                 dev_kfree_skb(skb);
300                 return NULL;
301         }
302         for (i = 0; i < len; i++) {
303                 v110_buf[i] = 0;
304                 for (j = 0; j < v->nbytes; j++)
305                         v110_buf[i] |= (v->decodebuf[(i * v->nbytes) + j] & v->key) << (8 - ((j + 1) * v->nbits));
306                 v110_buf[i] = FlipBits(v110_buf[i], v->nbits);
307         }
308         v->decodelen = (v->decodelen % (10 * v->nbytes));
309         memcpy(v->decodebuf, &(v->decodebuf[len * v->nbytes]), v->decodelen);
310
311         skb_trim(skb, DecodeMatrix(v, v110_buf, len, skb->data));
312         kfree(v110_buf);
313         if (skb->len)
314                 return skb;
315         else {
316                 kfree_skb(skb);
317                 return NULL;
318         }
319 }
320
321 /* EncodeMatrix takes input data in buf, len is the bytecount.
322    Data is encoded into v110 frames in m. Return value is the number of
323    matrix-lines generated.
324  */
325 static int
326 EncodeMatrix(unsigned char *buf, int len, unsigned char *m, int mlen)
327 {
328         int line = 0;
329         int i = 0;
330         int mbit = 128;
331         int dbit = 1;
332         int introducer = 3;
333         int ibit[] = {0, 1, 1};
334
335         while ((i < len) && (line < mlen)) {    /* while we still have input data */
336                 switch (line % 10) {    /* in which line of the matrix are we? */
337                         case 0:
338                                 m[line++] = 0x00;       /* line 0 is always 0 */
339                                 mbit = 128;     /* go on with the 7th bit */
340                                 break;
341                         case 5:
342                                 m[line++] = 0xbf;       /* line 5 is always 10111111 */
343                                 mbit = 128;     /* go on with the 7th bit */
344                                 break;
345                 }
346                 if (line >= mlen) {
347                         printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!\n");
348                         return line;
349                 }
350         next_bit:
351                 switch (mbit) { /* leftmost or rightmost bit ? */
352                         case 1:
353                                 line++; /* rightmost -> go to next line */
354                                 if (line >= mlen) {
355                                         printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!\n");
356                                         return line;
357                                 }
358                         case 128:
359                                 m[line] = 128;  /* leftmost -> set byte to 1000000 */
360                                 mbit = 64;      /* current bit in the matrix line */
361                                 continue;
362                 }
363                 if (introducer) {       /* set 110 sequence ? */
364                         introducer--;   /* set on digit less */
365                         m[line] |= ibit[introducer] ? mbit : 0; /* set corresponding bit */
366                         mbit >>= 1;     /* bit of matrix line  >> 1 */
367                         goto next_bit;  /* and go on there */
368                 }               /* else push data bits into the matrix! */
369                 m[line] |= (buf[i] & dbit) ? mbit : 0;  /* set data bit in matrix */
370                 if (dbit == 128) {      /* was it the last one? */
371                         dbit = 1;       /* then go on with first bit of  */
372                         i++;            /* next byte in input buffer */
373                         if (i < len)    /* input buffer done ? */
374                                 introducer = 3; /* no, write introducer 110 */
375                         else {  /* input buffer done ! */
376                                 m[line] |= (mbit - 1) & 0xfe;   /* set remaining bits in line to 1 */
377                                 break;
378                         }
379                 } else          /* not the last data bit */
380                         dbit <<= 1;     /* then go to next data bit */
381                 mbit >>= 1;     /* go to next bit of matrix */
382                 goto next_bit;
383
384         }
385         /* if necessary, generate remaining lines of the matrix... */
386         if ((line) && ((line + 10) < mlen))
387                 switch (++line % 10) {
388                         case 1:
389                                 m[line++] = 0xfe;
390                         case 2:
391                                 m[line++] = 0xfe;
392                         case 3:
393                                 m[line++] = 0xfe;
394                         case 4:
395                                 m[line++] = 0xfe;
396                         case 5:
397                                 m[line++] = 0xbf;
398                         case 6:
399                                 m[line++] = 0xfe;
400                         case 7:
401                                 m[line++] = 0xfe;
402                         case 8:
403                                 m[line++] = 0xfe;
404                         case 9:
405                                 m[line++] = 0xfe;
406                 }
407         return line;            /* that's how many lines we have */
408 }
409
410 /*
411  * Build a sync frame.
412  */
413 static struct sk_buff *
414 isdn_v110_sync(isdn_v110_stream *v)
415 {
416         struct sk_buff *skb;
417
418         if (v == NULL) {
419                 /* invalid handle, no chance to proceed */
420                 printk(KERN_WARNING "isdn_v110_sync called with NULL stream!\n");
421                 return NULL;
422         }
423         if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
424                 skb_reserve(skb, v->skbres);
425                 memcpy(skb_put(skb, v->framelen), v->OfflineFrame, v->framelen);
426         }
427         return skb;
428 }
429
430 /*
431  * Build an idle frame.
432  */
433 static struct sk_buff *
434 isdn_v110_idle(isdn_v110_stream *v)
435 {
436         struct sk_buff *skb;
437
438         if (v == NULL) {
439                 /* invalid handle, no chance to proceed */
440                 printk(KERN_WARNING "isdn_v110_sync called with NULL stream!\n");
441                 return NULL;
442         }
443         if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
444                 skb_reserve(skb, v->skbres);
445                 memcpy(skb_put(skb, v->framelen), v->OnlineFrame, v->framelen);
446         }
447         return skb;
448 }
449
450 struct sk_buff *
451 isdn_v110_encode(isdn_v110_stream * v, struct sk_buff *skb)
452 {
453         int i;
454         int j;
455         int rlen;
456         int mlen;
457         int olen;
458         int size;
459         int sval1;
460         int sval2;
461         int nframes;
462         unsigned char *v110buf;
463         unsigned char *rbuf;
464         struct sk_buff *nskb;
465
466         if (v == NULL) {
467                 /* invalid handle, no chance to proceed */
468                 printk(KERN_WARNING "isdn_v110_encode called with NULL stream!\n");
469                 return NULL;
470         }
471         if (!skb) {
472                 /* invalid skb, no chance to proceed */
473                 printk(KERN_WARNING "isdn_v110_encode called with NULL skb!\n");
474                 return NULL;
475         }
476         rlen = skb->len;
477         nframes = (rlen + 3) / 4;
478         v110buf = v->encodebuf;
479         if ((nframes * 40) > v->maxsize) {
480                 size = v->maxsize;
481                 rlen = v->maxsize / 40;
482         } else
483                 size = nframes * 40;
484         if (!(nskb = dev_alloc_skb(size + v->skbres + sizeof(int)))) {
485                 printk(KERN_WARNING "isdn_v110_encode: Couldn't alloc skb\n");
486                 return NULL;
487         }
488         skb_reserve(nskb, v->skbres + sizeof(int));
489         if (skb->len == 0) {
490                 memcpy(skb_put(nskb, v->framelen), v->OnlineFrame, v->framelen);
491                 *((int *)skb_push(nskb, sizeof(int))) = 0;
492                 return nskb;
493         }
494         mlen = EncodeMatrix(skb->data, rlen, v110buf, size);
495         /* now distribute 2 or 4 bits each to the output stream! */
496         rbuf = skb_put(nskb, size);
497         olen = 0;
498         sval1 = 8 - v->nbits;
499         sval2 = v->key << sval1;
500         for (i = 0; i < mlen; i++) {
501                 v110buf[i] = FlipBits(v110buf[i], v->nbits);
502                 for (j = 0; j < v->nbytes; j++) {
503                         if (size--)
504                                 *rbuf++ = ~v->key | (((v110buf[i] << (j * v->nbits)) & sval2) >> sval1);
505                         else {
506                                 printk(KERN_WARNING "isdn_v110_encode: buffers full!\n");
507                                 goto buffer_full;
508                         }
509                         olen++;
510                 }
511         }
512 buffer_full:
513         skb_trim(nskb, olen);
514         *((int *)skb_push(nskb, sizeof(int))) = rlen;
515         return nskb;
516 }
517
518 int
519 isdn_v110_stat_callback(int idx, isdn_ctrl *c)
520 {
521         isdn_v110_stream *v = NULL;
522         int i;
523         int ret = 0;
524
525         if (idx < 0)
526                 return 0;
527         switch (c->command) {
528                 case ISDN_STAT_BSENT:
529                         /* Keep the send-queue of the driver filled
530                          * with frames:
531                          * If number of outstanding frames < 3,
532                          * send down an Idle-Frame (or an Sync-Frame, if
533                          * v->SyncInit != 0). 
534                          */
535                         if (!(v = dev->v110[idx]))
536                                 return 0;
537                         atomic_inc(&dev->v110use[idx]);
538                         for (i=0; i * v->framelen < c->parm.length; i++) {
539                                 if (v->skbidle > 0) {
540                                         v->skbidle--;
541                                         ret = 1;
542                                 } else {
543                                         if (v->skbuser > 0)
544                                                 v->skbuser--;
545                                         ret = 0;
546                                 }
547                         }
548                         for (i = v->skbuser + v->skbidle; i < 2; i++) {
549                                 struct sk_buff *skb;
550                                 if (v->SyncInit > 0)
551                                         skb = isdn_v110_sync(v);
552                                 else
553                                         skb = isdn_v110_idle(v);
554                                 if (skb) {
555                                         if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
556                                                 dev_kfree_skb(skb);
557                                                 break;
558                                         } else {
559                                                 if (v->SyncInit)
560                                                         v->SyncInit--;
561                                                 v->skbidle++;
562                                         }
563                                 } else
564                                         break;
565                         }
566                         atomic_dec(&dev->v110use[idx]);
567                         return ret;
568                 case ISDN_STAT_DHUP:
569                 case ISDN_STAT_BHUP:
570                         while (1) {
571                                 atomic_inc(&dev->v110use[idx]);
572                                 if (atomic_dec_and_test(&dev->v110use[idx])) {
573                                         isdn_v110_close(dev->v110[idx]);
574                                         dev->v110[idx] = NULL;
575                                         break;
576                                 }
577                                 mdelay(1);
578                         }
579                         break;
580                 case ISDN_STAT_BCONN:
581                         if (dev->v110emu[idx] && (dev->v110[idx] == NULL)) {
582                                 int hdrlen = dev->drv[c->driver]->interface->hl_hdrlen;
583                                 int maxsize = dev->drv[c->driver]->interface->maxbufsize;
584                                 atomic_inc(&dev->v110use[idx]);
585                                 switch (dev->v110emu[idx]) {
586                                         case ISDN_PROTO_L2_V11096:
587                                                 dev->v110[idx] = isdn_v110_open(V110_9600, hdrlen, maxsize);
588                                                 break;
589                                         case ISDN_PROTO_L2_V11019:
590                                                 dev->v110[idx] = isdn_v110_open(V110_19200, hdrlen, maxsize);
591                                                 break;
592                                         case ISDN_PROTO_L2_V11038:
593                                                 dev->v110[idx] = isdn_v110_open(V110_38400, hdrlen, maxsize);
594                                                 break;
595                                         default:;
596                                 }
597                                 if ((v = dev->v110[idx])) {
598                                         while (v->SyncInit) {
599                                                 struct sk_buff *skb = isdn_v110_sync(v);
600                                                 if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
601                                                         dev_kfree_skb(skb);
602                                                         /* Unable to send, try later */
603                                                         break;
604                                                 }
605                                                 v->SyncInit--;
606                                                 v->skbidle++;
607                                         }
608                                 } else
609                                         printk(KERN_WARNING "isdn_v110: Couldn't open stream for chan %d\n", idx);
610                                 atomic_dec(&dev->v110use[idx]);
611                         }
612                         break;
613                 default:
614                         return 0;
615         }
616         return 0;
617 }