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Committer: Michael Beasley <mike@snafu.setup>
[mikesnafu-overlay.git] / drivers / isdn / gigaset / asyncdata.c
blob091deb9d1c47cfb85e5252effbf019d65aba67e3
1 /*
2 * Common data handling layer for ser_gigaset and usb_gigaset
3 *
4 * Copyright (c) 2005 by Tilman Schmidt <tilman@imap.cc>,
5 * Hansjoerg Lipp <hjlipp@web.de>,
6 * Stefan Eilers.
7 *
8 * =====================================================================
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation; either version 2 of
12 * the License, or (at your option) any later version.
13 * =====================================================================
14 */
15
16 #include "gigaset.h"
17 #include <linux/crc-ccitt.h>
18 #include <linux/bitrev.h>
19
20 //#define GIG_M10x_STUFF_VOICE_DATA
21
22 /* check if byte must be stuffed/escaped
23 * I'm not sure which data should be encoded.
24 * Therefore I will go the hard way and decode every value
25 * less than 0x20, the flag sequence and the control escape char.
26 */
27 static inline int muststuff(unsigned char c)
28 {
29 if (c < PPP_TRANS) return 1;
30 if (c == PPP_FLAG) return 1;
31 if (c == PPP_ESCAPE) return 1;
32 /* other possible candidates: */
33 /* 0x91: XON with parity set */
34 /* 0x93: XOFF with parity set */
35 return 0;
36 }
37
38 /* == data input =========================================================== */
39
40 /* process a block of received bytes in command mode (modem response)
41 * Return value:
42 * number of processed bytes
43 */
44 static inline int cmd_loop(unsigned char c, unsigned char *src, int numbytes,
45 struct inbuf_t *inbuf)
46 {
47 struct cardstate *cs = inbuf->cs;
48 unsigned cbytes = cs->cbytes;
49 int inputstate = inbuf->inputstate;
50 int startbytes = numbytes;
51
52 for (;;) {
53 cs->respdata[cbytes] = c;
54 if (c == 10 || c == 13) {
55 gig_dbg(DEBUG_TRANSCMD, "%s: End of Command (%d Bytes)",
56 __func__, cbytes);
57 cs->cbytes = cbytes;
58 gigaset_handle_modem_response(cs); /* can change
59 cs->dle */
60 cbytes = 0;
61
62 if (cs->dle &&
63 !(inputstate & INS_DLE_command)) {
64 inputstate &= ~INS_command;
65 break;
66 }
67 } else {
68 /* advance in line buffer, checking for overflow */
69 if (cbytes < MAX_RESP_SIZE - 1)
70 cbytes++;
71 else
72 dev_warn(cs->dev, "response too large\n");
73 }
74
75 if (!numbytes)
76 break;
77 c = *src++;
78 --numbytes;
79 if (c == DLE_FLAG &&
80 (cs->dle || inputstate & INS_DLE_command)) {
81 inputstate |= INS_DLE_char;
82 break;
83 }
84 }
85
86 cs->cbytes = cbytes;
87 inbuf->inputstate = inputstate;
88
89 return startbytes - numbytes;
90 }
91
92 /* process a block of received bytes in lock mode (tty i/f)
93 * Return value:
94 * number of processed bytes
95 */
96 static inline int lock_loop(unsigned char *src, int numbytes,
97 struct inbuf_t *inbuf)
98 {
99 struct cardstate *cs = inbuf->cs;
100
101 gigaset_dbg_buffer(DEBUG_LOCKCMD, "received response",
102 numbytes, src);
103 gigaset_if_receive(cs, src, numbytes);
104
105 return numbytes;
106 }
107
108 /* process a block of received bytes in HDLC data mode
109 * Collect HDLC frames, undoing byte stuffing and watching for DLE escapes.
110 * When a frame is complete, check the FCS and pass valid frames to the LL.
111 * If DLE is encountered, return immediately to let the caller handle it.
112 * Return value:
113 * number of processed bytes
114 * numbytes (all bytes processed) on error --FIXME
115 */
116 static inline int hdlc_loop(unsigned char c, unsigned char *src, int numbytes,
117 struct inbuf_t *inbuf)
118 {
119 struct cardstate *cs = inbuf->cs;
120 struct bc_state *bcs = inbuf->bcs;
121 int inputstate = bcs->inputstate;
122 __u16 fcs = bcs->fcs;
123 struct sk_buff *skb = bcs->skb;
124 unsigned char error;
125 struct sk_buff *compskb;
126 int startbytes = numbytes;
127 int l;
128
129 if (unlikely(inputstate & INS_byte_stuff)) {
130 inputstate &= ~INS_byte_stuff;
131 goto byte_stuff;
132 }
133 for (;;) {
134 if (unlikely(c == PPP_ESCAPE)) {
135 if (unlikely(!numbytes)) {
136 inputstate |= INS_byte_stuff;
137 break;
138 }
139 c = *src++;
140 --numbytes;
141 if (unlikely(c == DLE_FLAG &&
142 (cs->dle ||
143 inbuf->inputstate & INS_DLE_command))) {
144 inbuf->inputstate |= INS_DLE_char;
145 inputstate |= INS_byte_stuff;
146 break;
147 }
148 byte_stuff:
149 c ^= PPP_TRANS;
150 #ifdef CONFIG_GIGASET_DEBUG
151 if (unlikely(!muststuff(c)))
152 gig_dbg(DEBUG_HDLC, "byte stuffed: 0x%02x", c);
153 #endif
154 } else if (unlikely(c == PPP_FLAG)) {
155 if (unlikely(inputstate & INS_skip_frame)) {
156 if (!(inputstate & INS_have_data)) { /* 7E 7E */
157 #ifdef CONFIG_GIGASET_DEBUG
158 ++bcs->emptycount;
159 #endif
160 } else
161 gig_dbg(DEBUG_HDLC,
162 "7e----------------------------");
163
164 /* end of frame */
165 error = 1;
166 gigaset_rcv_error(NULL, cs, bcs);
167 } else if (!(inputstate & INS_have_data)) { /* 7E 7E */
168 #ifdef CONFIG_GIGASET_DEBUG
169 ++bcs->emptycount;
170 #endif
171 break;
172 } else {
173 gig_dbg(DEBUG_HDLC,
174 "7e----------------------------");
175
176 /* end of frame */
177 error = 0;
178
179 if (unlikely(fcs != PPP_GOODFCS)) {
180 dev_err(cs->dev,
181 "Packet checksum at %lu failed, "
182 "packet is corrupted (%u bytes)!\n",
183 bcs->rcvbytes, skb->len);
184 compskb = NULL;
185 gigaset_rcv_error(compskb, cs, bcs);
186 error = 1;
187 } else {
188 if (likely((l = skb->len) > 2)) {
189 skb->tail -= 2;
190 skb->len -= 2;
191 } else {
192 dev_kfree_skb(skb);
193 skb = NULL;
194 inputstate |= INS_skip_frame;
195 if (l == 1) {
196 dev_err(cs->dev,
197 "invalid packet size (1)!\n");
198 error = 1;
199 gigaset_rcv_error(NULL,
200 cs, bcs);
201 }
202 }
203 if (likely(!(error ||
204 (inputstate &
205 INS_skip_frame)))) {
206 gigaset_rcv_skb(skb, cs, bcs);
207 }
208 }
209 }
210
211 if (unlikely(error))
212 if (skb)
213 dev_kfree_skb(skb);
214
215 fcs = PPP_INITFCS;
216 inputstate &= ~(INS_have_data | INS_skip_frame);
217 if (unlikely(bcs->ignore)) {
218 inputstate |= INS_skip_frame;
219 skb = NULL;
220 } else if (likely((skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN)) != NULL)) {
221 skb_reserve(skb, HW_HDR_LEN);
222 } else {
223 dev_warn(cs->dev,
224 "could not allocate new skb\n");
225 inputstate |= INS_skip_frame;
226 }
227
228 break;
229 #ifdef CONFIG_GIGASET_DEBUG
230 } else if (unlikely(muststuff(c))) {
231 /* Should not happen. Possible after ZDLE=1<CR><LF>. */
232 gig_dbg(DEBUG_HDLC, "not byte stuffed: 0x%02x", c);
233 #endif
234 }
235
236 /* add character */
237
238 #ifdef CONFIG_GIGASET_DEBUG
239 if (unlikely(!(inputstate & INS_have_data))) {
240 gig_dbg(DEBUG_HDLC, "7e (%d x) ================",
241 bcs->emptycount);
242 bcs->emptycount = 0;
243 }
244 #endif
245
246 inputstate |= INS_have_data;
247
248 if (likely(!(inputstate & INS_skip_frame))) {
249 if (unlikely(skb->len == SBUFSIZE)) {
250 dev_warn(cs->dev, "received packet too long\n");
251 dev_kfree_skb_any(skb);
252 skb = NULL;
253 inputstate |= INS_skip_frame;
254 break;
255 }
256 *__skb_put(skb, 1) = c;
257 fcs = crc_ccitt_byte(fcs, c);
258 }
259
260 if (unlikely(!numbytes))
261 break;
262 c = *src++;
263 --numbytes;
264 if (unlikely(c == DLE_FLAG &&
265 (cs->dle ||
266 inbuf->inputstate & INS_DLE_command))) {
267 inbuf->inputstate |= INS_DLE_char;
268 break;
269 }
270 }
271 bcs->inputstate = inputstate;
272 bcs->fcs = fcs;
273 bcs->skb = skb;
274 return startbytes - numbytes;
275 }
276
277 /* process a block of received bytes in transparent data mode
278 * Invert bytes, undoing byte stuffing and watching for DLE escapes.
279 * If DLE is encountered, return immediately to let the caller handle it.
280 * Return value:
281 * number of processed bytes
282 * numbytes (all bytes processed) on error --FIXME
283 */
284 static inline int iraw_loop(unsigned char c, unsigned char *src, int numbytes,
285 struct inbuf_t *inbuf)
286 {
287 struct cardstate *cs = inbuf->cs;
288 struct bc_state *bcs = inbuf->bcs;
289 int inputstate = bcs->inputstate;
290 struct sk_buff *skb = bcs->skb;
291 int startbytes = numbytes;
292
293 for (;;) {
294 /* add character */
295 inputstate |= INS_have_data;
296
297 if (likely(!(inputstate & INS_skip_frame))) {
298 if (unlikely(skb->len == SBUFSIZE)) {
299 //FIXME just pass skb up and allocate a new one
300 dev_warn(cs->dev, "received packet too long\n");
301 dev_kfree_skb_any(skb);
302 skb = NULL;
303 inputstate |= INS_skip_frame;
304 break;
305 }
306 *__skb_put(skb, 1) = bitrev8(c);
307 }
308
309 if (unlikely(!numbytes))
310 break;
311 c = *src++;
312 --numbytes;
313 if (unlikely(c == DLE_FLAG &&
314 (cs->dle ||
315 inbuf->inputstate & INS_DLE_command))) {
316 inbuf->inputstate |= INS_DLE_char;
317 break;
318 }
319 }
320
321 /* pass data up */
322 if (likely(inputstate & INS_have_data)) {
323 if (likely(!(inputstate & INS_skip_frame))) {
324 gigaset_rcv_skb(skb, cs, bcs);
325 }
326 inputstate &= ~(INS_have_data | INS_skip_frame);
327 if (unlikely(bcs->ignore)) {
328 inputstate |= INS_skip_frame;
329 skb = NULL;
330 } else if (likely((skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN))
331 != NULL)) {
332 skb_reserve(skb, HW_HDR_LEN);
333 } else {
334 dev_warn(cs->dev, "could not allocate new skb\n");
335 inputstate |= INS_skip_frame;
336 }
337 }
338
339 bcs->inputstate = inputstate;
340 bcs->skb = skb;
341 return startbytes - numbytes;
342 }
343
344 /* process a block of data received from the device
345 */
346 void gigaset_m10x_input(struct inbuf_t *inbuf)
347 {
348 struct cardstate *cs;
349 unsigned tail, head, numbytes;
350 unsigned char *src, c;
351 int procbytes;
352
353 head = inbuf->head;
354 tail = inbuf->tail;
355 gig_dbg(DEBUG_INTR, "buffer state: %u -> %u", head, tail);
356
357 if (head != tail) {
358 cs = inbuf->cs;
359 src = inbuf->data + head;
360 numbytes = (head > tail ? RBUFSIZE : tail) - head;
361 gig_dbg(DEBUG_INTR, "processing %u bytes", numbytes);
362
363 while (numbytes) {
364 if (cs->mstate == MS_LOCKED) {
365 procbytes = lock_loop(src, numbytes, inbuf);
366 src += procbytes;
367 numbytes -= procbytes;
368 } else {
369 c = *src++;
370 --numbytes;
371 if (c == DLE_FLAG && (cs->dle ||
372 inbuf->inputstate & INS_DLE_command)) {
373 if (!(inbuf->inputstate & INS_DLE_char)) {
374 inbuf->inputstate |= INS_DLE_char;
375 goto nextbyte;
376 }
377 /* <DLE> <DLE> => <DLE> in data stream */
378 inbuf->inputstate &= ~INS_DLE_char;
379 }
380
381 if (!(inbuf->inputstate & INS_DLE_char)) {
382
383 /* FIXME use function pointers? */
384 if (inbuf->inputstate & INS_command)
385 procbytes = cmd_loop(c, src, numbytes, inbuf);
386 else if (inbuf->bcs->proto2 == ISDN_PROTO_L2_HDLC)
387 procbytes = hdlc_loop(c, src, numbytes, inbuf);
388 else
389 procbytes = iraw_loop(c, src, numbytes, inbuf);
390
391 src += procbytes;
392 numbytes -= procbytes;
393 } else { /* DLE char */
394 inbuf->inputstate &= ~INS_DLE_char;
395 switch (c) {
396 case 'X': /*begin of command*/
397 #ifdef CONFIG_GIGASET_DEBUG
398 if (inbuf->inputstate & INS_command)
399 dev_err(cs->dev,
400 "received <DLE> 'X' in command mode\n");
401 #endif
402 inbuf->inputstate |=
403 INS_command | INS_DLE_command;
404 break;
405 case '.': /*end of command*/
406 #ifdef CONFIG_GIGASET_DEBUG
407 if (!(inbuf->inputstate & INS_command))
408 dev_err(cs->dev,
409 "received <DLE> '.' in hdlc mode\n");
410 #endif
411 inbuf->inputstate &= cs->dle ?
412 ~(INS_DLE_command|INS_command)
413 : ~INS_DLE_command;
414 break;
415 //case DLE_FLAG: /*DLE_FLAG in data stream*/ /* schon oben behandelt! */
416 default:
417 dev_err(cs->dev,
418 "received 0x10 0x%02x!\n",
419 (int) c);
420 /* FIXME: reset driver?? */
421 }
422 }
423 }
424 nextbyte:
425 if (!numbytes) {
426 /* end of buffer, check for wrap */
427 if (head > tail) {
428 head = 0;
429 src = inbuf->data;
430 numbytes = tail;
431 } else {
432 head = tail;
433 break;
434 }
435 }
436 }
437
438 gig_dbg(DEBUG_INTR, "setting head to %u", head);
439 inbuf->head = head;
440 }
441 }
442 EXPORT_SYMBOL_GPL(gigaset_m10x_input);
443
444
445 /* == data output ========================================================== */
446
447 /* Encoding of a PPP packet into an octet stuffed HDLC frame
448 * with FCS, opening and closing flags.
449 * parameters:
450 * skb skb containing original packet (freed upon return)
451 * head number of headroom bytes to allocate in result skb
452 * tail number of tailroom bytes to allocate in result skb
453 * Return value:
454 * pointer to newly allocated skb containing the result frame
455 */
456 static struct sk_buff *HDLC_Encode(struct sk_buff *skb, int head, int tail)
457 {
458 struct sk_buff *hdlc_skb;
459 __u16 fcs;
460 unsigned char c;
461 unsigned char *cp;
462 int len;
463 unsigned int stuf_cnt;
464
465 stuf_cnt = 0;
466 fcs = PPP_INITFCS;
467 cp = skb->data;
468 len = skb->len;
469 while (len--) {
470 if (muststuff(*cp))
471 stuf_cnt++;
472 fcs = crc_ccitt_byte(fcs, *cp++);
473 }
474 fcs ^= 0xffff; /* complement */
475
476 /* size of new buffer: original size + number of stuffing bytes
477 * + 2 bytes FCS + 2 stuffing bytes for FCS (if needed) + 2 flag bytes
478 */
479 hdlc_skb = dev_alloc_skb(skb->len + stuf_cnt + 6 + tail + head);
480 if (!hdlc_skb) {
481 dev_kfree_skb(skb);
482 return NULL;
483 }
484 skb_reserve(hdlc_skb, head);
485
486 /* Copy acknowledge request into new skb */
487 memcpy(hdlc_skb->head, skb->head, 2);
488
489 /* Add flag sequence in front of everything.. */
490 *(skb_put(hdlc_skb, 1)) = PPP_FLAG;
491
492 /* Perform byte stuffing while copying data. */
493 while (skb->len--) {
494 if (muststuff(*skb->data)) {
495 *(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
496 *(skb_put(hdlc_skb, 1)) = (*skb->data++) ^ PPP_TRANS;
497 } else
498 *(skb_put(hdlc_skb, 1)) = *skb->data++;
499 }
500
501 /* Finally add FCS (byte stuffed) and flag sequence */
502 c = (fcs & 0x00ff); /* least significant byte first */
503 if (muststuff(c)) {
504 *(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
505 c ^= PPP_TRANS;
506 }
507 *(skb_put(hdlc_skb, 1)) = c;
508
509 c = ((fcs >> 8) & 0x00ff);
510 if (muststuff(c)) {
511 *(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
512 c ^= PPP_TRANS;
513 }
514 *(skb_put(hdlc_skb, 1)) = c;
515
516 *(skb_put(hdlc_skb, 1)) = PPP_FLAG;
517
518 dev_kfree_skb(skb);
519 return hdlc_skb;
520 }
521
522 /* Encoding of a raw packet into an octet stuffed bit inverted frame
523 * parameters:
524 * skb skb containing original packet (freed upon return)
525 * head number of headroom bytes to allocate in result skb
526 * tail number of tailroom bytes to allocate in result skb
527 * Return value:
528 * pointer to newly allocated skb containing the result frame
529 */
530 static struct sk_buff *iraw_encode(struct sk_buff *skb, int head, int tail)
531 {
532 struct sk_buff *iraw_skb;
533 unsigned char c;
534 unsigned char *cp;
535 int len;
536
537 /* worst case: every byte must be stuffed */
538 iraw_skb = dev_alloc_skb(2*skb->len + tail + head);
539 if (!iraw_skb) {
540 dev_kfree_skb(skb);
541 return NULL;
542 }
543 skb_reserve(iraw_skb, head);
544
545 cp = skb->data;
546 len = skb->len;
547 while (len--) {
548 c = bitrev8(*cp++);
549 if (c == DLE_FLAG)
550 *(skb_put(iraw_skb, 1)) = c;
551 *(skb_put(iraw_skb, 1)) = c;
552 }
553 dev_kfree_skb(skb);
554 return iraw_skb;
555 }
556
557 /* gigaset_send_skb
558 * called by common.c to queue an skb for sending
559 * and start transmission if necessary
560 * parameters:
561 * B Channel control structure
562 * skb
563 * Return value:
564 * number of bytes accepted for sending
565 * (skb->len if ok, 0 if out of buffer space)
566 * or error code (< 0, eg. -EINVAL)
567 */
568 int gigaset_m10x_send_skb(struct bc_state *bcs, struct sk_buff *skb)
569 {
570 unsigned len = skb->len;
571 unsigned long flags;
572
573 if (bcs->proto2 == ISDN_PROTO_L2_HDLC)
574 skb = HDLC_Encode(skb, HW_HDR_LEN, 0);
575 else
576 skb = iraw_encode(skb, HW_HDR_LEN, 0);
577 if (!skb) {
578 err("unable to allocate memory for encoding!\n");
579 return -ENOMEM;
580 }
581
582 skb_queue_tail(&bcs->squeue, skb);
583 spin_lock_irqsave(&bcs->cs->lock, flags);
584 if (bcs->cs->connected)
585 tasklet_schedule(&bcs->cs->write_tasklet);
586 spin_unlock_irqrestore(&bcs->cs->lock, flags);
587
588 return len; /* ok so far */
589 }
590 EXPORT_SYMBOL_GPL(gigaset_m10x_send_skb);
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