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Linux 3.8-rc7
[cris-mirror.git] / net / nfc / hci / llc_shdlc.c
blob27b313befc35eff1f5cfceb41f8ecf9be618c159
1 /*
2 * shdlc Link Layer Control
3 *
4 * Copyright (C) 2012 Intel Corporation. All rights reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the
17 * Free Software Foundation, Inc.,
18 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 */
20
21 #define pr_fmt(fmt) "shdlc: %s: " fmt, __func__
22
23 #include <linux/types.h>
24 #include <linux/sched.h>
25 #include <linux/wait.h>
26 #include <linux/slab.h>
27 #include <linux/skbuff.h>
28
29 #include "llc.h"
30
31 enum shdlc_state {
32 SHDLC_DISCONNECTED = 0,
33 SHDLC_CONNECTING = 1,
34 SHDLC_NEGOTIATING = 2,
35 SHDLC_HALF_CONNECTED = 3,
36 SHDLC_CONNECTED = 4
37 };
38
39 struct llc_shdlc {
40 struct nfc_hci_dev *hdev;
41 xmit_to_drv_t xmit_to_drv;
42 rcv_to_hci_t rcv_to_hci;
43
44 struct mutex state_mutex;
45 enum shdlc_state state;
46 int hard_fault;
47
48 wait_queue_head_t *connect_wq;
49 int connect_tries;
50 int connect_result;
51 struct timer_list connect_timer;/* aka T3 in spec 10.6.1 */
52
53 u8 w; /* window size */
54 bool srej_support;
55
56 struct timer_list t1_timer; /* send ack timeout */
57 bool t1_active;
58
59 struct timer_list t2_timer; /* guard/retransmit timeout */
60 bool t2_active;
61
62 int ns; /* next seq num for send */
63 int nr; /* next expected seq num for receive */
64 int dnr; /* oldest sent unacked seq num */
65
66 struct sk_buff_head rcv_q;
67
68 struct sk_buff_head send_q;
69 bool rnr; /* other side is not ready to receive */
70
71 struct sk_buff_head ack_pending_q;
72
73 struct work_struct sm_work;
74
75 int tx_headroom;
76 int tx_tailroom;
77
78 llc_failure_t llc_failure;
79 };
80
81 #define SHDLC_LLC_HEAD_ROOM 2
82
83 #define SHDLC_MAX_WINDOW 4
84 #define SHDLC_SREJ_SUPPORT false
85
86 #define SHDLC_CONTROL_HEAD_MASK 0xe0
87 #define SHDLC_CONTROL_HEAD_I 0x80
88 #define SHDLC_CONTROL_HEAD_I2 0xa0
89 #define SHDLC_CONTROL_HEAD_S 0xc0
90 #define SHDLC_CONTROL_HEAD_U 0xe0
91
92 #define SHDLC_CONTROL_NS_MASK 0x38
93 #define SHDLC_CONTROL_NR_MASK 0x07
94 #define SHDLC_CONTROL_TYPE_MASK 0x18
95
96 #define SHDLC_CONTROL_M_MASK 0x1f
97
98 enum sframe_type {
99 S_FRAME_RR = 0x00,
100 S_FRAME_REJ = 0x01,
101 S_FRAME_RNR = 0x02,
102 S_FRAME_SREJ = 0x03
103 };
104
105 enum uframe_modifier {
106 U_FRAME_UA = 0x06,
107 U_FRAME_RSET = 0x19
108 };
109
110 #define SHDLC_CONNECT_VALUE_MS 5
111 #define SHDLC_T1_VALUE_MS(w) ((5 * w) / 4)
112 #define SHDLC_T2_VALUE_MS 300
113
114 #define SHDLC_DUMP_SKB(info, skb) \
115 do { \
116 pr_debug("%s:\n", info); \
117 print_hex_dump(KERN_DEBUG, "shdlc: ", DUMP_PREFIX_OFFSET, \
118 16, 1, skb->data, skb->len, 0); \
119 } while (0)
120
121 /* checks x < y <= z modulo 8 */
122 static bool llc_shdlc_x_lt_y_lteq_z(int x, int y, int z)
123 {
124 if (x < z)
125 return ((x < y) && (y <= z)) ? true : false;
126 else
127 return ((y > x) || (y <= z)) ? true : false;
128 }
129
130 /* checks x <= y < z modulo 8 */
131 static bool llc_shdlc_x_lteq_y_lt_z(int x, int y, int z)
132 {
133 if (x <= z)
134 return ((x <= y) && (y < z)) ? true : false;
135 else /* x > z -> z+8 > x */
136 return ((y >= x) || (y < z)) ? true : false;
137 }
138
139 static struct sk_buff *llc_shdlc_alloc_skb(struct llc_shdlc *shdlc,
140 int payload_len)
141 {
142 struct sk_buff *skb;
143
144 skb = alloc_skb(shdlc->tx_headroom + SHDLC_LLC_HEAD_ROOM +
145 shdlc->tx_tailroom + payload_len, GFP_KERNEL);
146 if (skb)
147 skb_reserve(skb, shdlc->tx_headroom + SHDLC_LLC_HEAD_ROOM);
148
149 return skb;
150 }
151
152 /* immediately sends an S frame. */
153 static int llc_shdlc_send_s_frame(struct llc_shdlc *shdlc,
154 enum sframe_type sframe_type, int nr)
155 {
156 int r;
157 struct sk_buff *skb;
158
159 pr_debug("sframe_type=%d nr=%d\n", sframe_type, nr);
160
161 skb = llc_shdlc_alloc_skb(shdlc, 0);
162 if (skb == NULL)
163 return -ENOMEM;
164
165 *skb_push(skb, 1) = SHDLC_CONTROL_HEAD_S | (sframe_type << 3) | nr;
166
167 r = shdlc->xmit_to_drv(shdlc->hdev, skb);
168
169 kfree_skb(skb);
170
171 return r;
172 }
173
174 /* immediately sends an U frame. skb may contain optional payload */
175 static int llc_shdlc_send_u_frame(struct llc_shdlc *shdlc,
176 struct sk_buff *skb,
177 enum uframe_modifier uframe_modifier)
178 {
179 int r;
180
181 pr_debug("uframe_modifier=%d\n", uframe_modifier);
182
183 *skb_push(skb, 1) = SHDLC_CONTROL_HEAD_U | uframe_modifier;
184
185 r = shdlc->xmit_to_drv(shdlc->hdev, skb);
186
187 kfree_skb(skb);
188
189 return r;
190 }
191
192 /*
193 * Free ack_pending frames until y_nr - 1, and reset t2 according to
194 * the remaining oldest ack_pending frame sent time
195 */
196 static void llc_shdlc_reset_t2(struct llc_shdlc *shdlc, int y_nr)
197 {
198 struct sk_buff *skb;
199 int dnr = shdlc->dnr; /* MUST initially be < y_nr */
200
201 pr_debug("release ack pending up to frame %d excluded\n", y_nr);
202
203 while (dnr != y_nr) {
204 pr_debug("release ack pending frame %d\n", dnr);
205
206 skb = skb_dequeue(&shdlc->ack_pending_q);
207 kfree_skb(skb);
208
209 dnr = (dnr + 1) % 8;
210 }
211
212 if (skb_queue_empty(&shdlc->ack_pending_q)) {
213 if (shdlc->t2_active) {
214 del_timer_sync(&shdlc->t2_timer);
215 shdlc->t2_active = false;
216
217 pr_debug
218 ("All sent frames acked. Stopped T2(retransmit)\n");
219 }
220 } else {
221 skb = skb_peek(&shdlc->ack_pending_q);
222
223 mod_timer(&shdlc->t2_timer, *(unsigned long *)skb->cb +
224 msecs_to_jiffies(SHDLC_T2_VALUE_MS));
225 shdlc->t2_active = true;
226
227 pr_debug
228 ("Start T2(retransmit) for remaining unacked sent frames\n");
229 }
230 }
231
232 /*
233 * Receive validated frames from lower layer. skb contains HCI payload only.
234 * Handle according to algorithm at spec:10.8.2
235 */
236 static void llc_shdlc_rcv_i_frame(struct llc_shdlc *shdlc,
237 struct sk_buff *skb, int ns, int nr)
238 {
239 int x_ns = ns;
240 int y_nr = nr;
241
242 pr_debug("recvd I-frame %d, remote waiting frame %d\n", ns, nr);
243
244 if (shdlc->state != SHDLC_CONNECTED)
245 goto exit;
246
247 if (x_ns != shdlc->nr) {
248 llc_shdlc_send_s_frame(shdlc, S_FRAME_REJ, shdlc->nr);
249 goto exit;
250 }
251
252 if (shdlc->t1_active == false) {
253 shdlc->t1_active = true;
254 mod_timer(&shdlc->t1_timer, jiffies +
255 msecs_to_jiffies(SHDLC_T1_VALUE_MS(shdlc->w)));
256 pr_debug("(re)Start T1(send ack)\n");
257 }
258
259 if (skb->len) {
260 shdlc->rcv_to_hci(shdlc->hdev, skb);
261 skb = NULL;
262 }
263
264 shdlc->nr = (shdlc->nr + 1) % 8;
265
266 if (llc_shdlc_x_lt_y_lteq_z(shdlc->dnr, y_nr, shdlc->ns)) {
267 llc_shdlc_reset_t2(shdlc, y_nr);
268
269 shdlc->dnr = y_nr;
270 }
271
272 exit:
273 kfree_skb(skb);
274 }
275
276 static void llc_shdlc_rcv_ack(struct llc_shdlc *shdlc, int y_nr)
277 {
278 pr_debug("remote acked up to frame %d excluded\n", y_nr);
279
280 if (llc_shdlc_x_lt_y_lteq_z(shdlc->dnr, y_nr, shdlc->ns)) {
281 llc_shdlc_reset_t2(shdlc, y_nr);
282 shdlc->dnr = y_nr;
283 }
284 }
285
286 static void llc_shdlc_requeue_ack_pending(struct llc_shdlc *shdlc)
287 {
288 struct sk_buff *skb;
289
290 pr_debug("ns reset to %d\n", shdlc->dnr);
291
292 while ((skb = skb_dequeue_tail(&shdlc->ack_pending_q))) {
293 skb_pull(skb, 1); /* remove control field */
294 skb_queue_head(&shdlc->send_q, skb);
295 }
296 shdlc->ns = shdlc->dnr;
297 }
298
299 static void llc_shdlc_rcv_rej(struct llc_shdlc *shdlc, int y_nr)
300 {
301 struct sk_buff *skb;
302
303 pr_debug("remote asks retransmition from frame %d\n", y_nr);
304
305 if (llc_shdlc_x_lteq_y_lt_z(shdlc->dnr, y_nr, shdlc->ns)) {
306 if (shdlc->t2_active) {
307 del_timer_sync(&shdlc->t2_timer);
308 shdlc->t2_active = false;
309 pr_debug("Stopped T2(retransmit)\n");
310 }
311
312 if (shdlc->dnr != y_nr) {
313 while ((shdlc->dnr = ((shdlc->dnr + 1) % 8)) != y_nr) {
314 skb = skb_dequeue(&shdlc->ack_pending_q);
315 kfree_skb(skb);
316 }
317 }
318
319 llc_shdlc_requeue_ack_pending(shdlc);
320 }
321 }
322
323 /* See spec RR:10.8.3 REJ:10.8.4 */
324 static void llc_shdlc_rcv_s_frame(struct llc_shdlc *shdlc,
325 enum sframe_type s_frame_type, int nr)
326 {
327 struct sk_buff *skb;
328
329 if (shdlc->state != SHDLC_CONNECTED)
330 return;
331
332 switch (s_frame_type) {
333 case S_FRAME_RR:
334 llc_shdlc_rcv_ack(shdlc, nr);
335 if (shdlc->rnr == true) { /* see SHDLC 10.7.7 */
336 shdlc->rnr = false;
337 if (shdlc->send_q.qlen == 0) {
338 skb = llc_shdlc_alloc_skb(shdlc, 0);
339 if (skb)
340 skb_queue_tail(&shdlc->send_q, skb);
341 }
342 }
343 break;
344 case S_FRAME_REJ:
345 llc_shdlc_rcv_rej(shdlc, nr);
346 break;
347 case S_FRAME_RNR:
348 llc_shdlc_rcv_ack(shdlc, nr);
349 shdlc->rnr = true;
350 break;
351 default:
352 break;
353 }
354 }
355
356 static void llc_shdlc_connect_complete(struct llc_shdlc *shdlc, int r)
357 {
358 pr_debug("result=%d\n", r);
359
360 del_timer_sync(&shdlc->connect_timer);
361
362 if (r == 0) {
363 shdlc->ns = 0;
364 shdlc->nr = 0;
365 shdlc->dnr = 0;
366
367 shdlc->state = SHDLC_HALF_CONNECTED;
368 } else {
369 shdlc->state = SHDLC_DISCONNECTED;
370 }
371
372 shdlc->connect_result = r;
373
374 wake_up(shdlc->connect_wq);
375 }
376
377 static int llc_shdlc_connect_initiate(struct llc_shdlc *shdlc)
378 {
379 struct sk_buff *skb;
380
381 pr_debug("\n");
382
383 skb = llc_shdlc_alloc_skb(shdlc, 2);
384 if (skb == NULL)
385 return -ENOMEM;
386
387 *skb_put(skb, 1) = SHDLC_MAX_WINDOW;
388 *skb_put(skb, 1) = SHDLC_SREJ_SUPPORT ? 1 : 0;
389
390 return llc_shdlc_send_u_frame(shdlc, skb, U_FRAME_RSET);
391 }
392
393 static int llc_shdlc_connect_send_ua(struct llc_shdlc *shdlc)
394 {
395 struct sk_buff *skb;
396
397 pr_debug("\n");
398
399 skb = llc_shdlc_alloc_skb(shdlc, 0);
400 if (skb == NULL)
401 return -ENOMEM;
402
403 return llc_shdlc_send_u_frame(shdlc, skb, U_FRAME_UA);
404 }
405
406 static void llc_shdlc_rcv_u_frame(struct llc_shdlc *shdlc,
407 struct sk_buff *skb,
408 enum uframe_modifier u_frame_modifier)
409 {
410 u8 w = SHDLC_MAX_WINDOW;
411 bool srej_support = SHDLC_SREJ_SUPPORT;
412 int r;
413
414 pr_debug("u_frame_modifier=%d\n", u_frame_modifier);
415
416 switch (u_frame_modifier) {
417 case U_FRAME_RSET:
418 switch (shdlc->state) {
419 case SHDLC_NEGOTIATING:
420 case SHDLC_CONNECTING:
421 /*
422 * We sent RSET, but chip wants to negociate or we
423 * got RSET before we managed to send out our.
424 */
425 if (skb->len > 0)
426 w = skb->data[0];
427
428 if (skb->len > 1)
429 srej_support = skb->data[1] & 0x01 ? true :
430 false;
431
432 if ((w <= SHDLC_MAX_WINDOW) &&
433 (SHDLC_SREJ_SUPPORT || (srej_support == false))) {
434 shdlc->w = w;
435 shdlc->srej_support = srej_support;
436 r = llc_shdlc_connect_send_ua(shdlc);
437 llc_shdlc_connect_complete(shdlc, r);
438 }
439 break;
440 case SHDLC_HALF_CONNECTED:
441 /*
442 * Chip resent RSET due to its timeout - Ignote it
443 * as we already sent UA.
444 */
445 break;
446 case SHDLC_CONNECTED:
447 /*
448 * Chip wants to reset link. This is unexpected and
449 * unsupported.
450 */
451 shdlc->hard_fault = -ECONNRESET;
452 break;
453 default:
454 break;
455 }
456 break;
457 case U_FRAME_UA:
458 if ((shdlc->state == SHDLC_CONNECTING &&
459 shdlc->connect_tries > 0) ||
460 (shdlc->state == SHDLC_NEGOTIATING)) {
461 llc_shdlc_connect_complete(shdlc, 0);
462 shdlc->state = SHDLC_CONNECTED;
463 }
464 break;
465 default:
466 break;
467 }
468
469 kfree_skb(skb);
470 }
471
472 static void llc_shdlc_handle_rcv_queue(struct llc_shdlc *shdlc)
473 {
474 struct sk_buff *skb;
475 u8 control;
476 int nr;
477 int ns;
478 enum sframe_type s_frame_type;
479 enum uframe_modifier u_frame_modifier;
480
481 if (shdlc->rcv_q.qlen)
482 pr_debug("rcvQlen=%d\n", shdlc->rcv_q.qlen);
483
484 while ((skb = skb_dequeue(&shdlc->rcv_q)) != NULL) {
485 control = skb->data[0];
486 skb_pull(skb, 1);
487 switch (control & SHDLC_CONTROL_HEAD_MASK) {
488 case SHDLC_CONTROL_HEAD_I:
489 case SHDLC_CONTROL_HEAD_I2:
490 if (shdlc->state == SHDLC_HALF_CONNECTED)
491 shdlc->state = SHDLC_CONNECTED;
492
493 ns = (control & SHDLC_CONTROL_NS_MASK) >> 3;
494 nr = control & SHDLC_CONTROL_NR_MASK;
495 llc_shdlc_rcv_i_frame(shdlc, skb, ns, nr);
496 break;
497 case SHDLC_CONTROL_HEAD_S:
498 if (shdlc->state == SHDLC_HALF_CONNECTED)
499 shdlc->state = SHDLC_CONNECTED;
500
501 s_frame_type = (control & SHDLC_CONTROL_TYPE_MASK) >> 3;
502 nr = control & SHDLC_CONTROL_NR_MASK;
503 llc_shdlc_rcv_s_frame(shdlc, s_frame_type, nr);
504 kfree_skb(skb);
505 break;
506 case SHDLC_CONTROL_HEAD_U:
507 u_frame_modifier = control & SHDLC_CONTROL_M_MASK;
508 llc_shdlc_rcv_u_frame(shdlc, skb, u_frame_modifier);
509 break;
510 default:
511 pr_err("UNKNOWN Control=%d\n", control);
512 kfree_skb(skb);
513 break;
514 }
515 }
516 }
517
518 static int llc_shdlc_w_used(int ns, int dnr)
519 {
520 int unack_count;
521
522 if (dnr <= ns)
523 unack_count = ns - dnr;
524 else
525 unack_count = 8 - dnr + ns;
526
527 return unack_count;
528 }
529
530 /* Send frames according to algorithm at spec:10.8.1 */
531 static void llc_shdlc_handle_send_queue(struct llc_shdlc *shdlc)
532 {
533 struct sk_buff *skb;
534 int r;
535 unsigned long time_sent;
536
537 if (shdlc->send_q.qlen)
538 pr_debug
539 ("sendQlen=%d ns=%d dnr=%d rnr=%s w_room=%d unackQlen=%d\n",
540 shdlc->send_q.qlen, shdlc->ns, shdlc->dnr,
541 shdlc->rnr == false ? "false" : "true",
542 shdlc->w - llc_shdlc_w_used(shdlc->ns, shdlc->dnr),
543 shdlc->ack_pending_q.qlen);
544
545 while (shdlc->send_q.qlen && shdlc->ack_pending_q.qlen < shdlc->w &&
546 (shdlc->rnr == false)) {
547
548 if (shdlc->t1_active) {
549 del_timer_sync(&shdlc->t1_timer);
550 shdlc->t1_active = false;
551 pr_debug("Stopped T1(send ack)\n");
552 }
553
554 skb = skb_dequeue(&shdlc->send_q);
555
556 *skb_push(skb, 1) = SHDLC_CONTROL_HEAD_I | (shdlc->ns << 3) |
557 shdlc->nr;
558
559 pr_debug("Sending I-Frame %d, waiting to rcv %d\n", shdlc->ns,
560 shdlc->nr);
561 SHDLC_DUMP_SKB("shdlc frame written", skb);
562
563 r = shdlc->xmit_to_drv(shdlc->hdev, skb);
564 if (r < 0) {
565 shdlc->hard_fault = r;
566 break;
567 }
568
569 shdlc->ns = (shdlc->ns + 1) % 8;
570
571 time_sent = jiffies;
572 *(unsigned long *)skb->cb = time_sent;
573
574 skb_queue_tail(&shdlc->ack_pending_q, skb);
575
576 if (shdlc->t2_active == false) {
577 shdlc->t2_active = true;
578 mod_timer(&shdlc->t2_timer, time_sent +
579 msecs_to_jiffies(SHDLC_T2_VALUE_MS));
580 pr_debug("Started T2 (retransmit)\n");
581 }
582 }
583 }
584
585 static void llc_shdlc_connect_timeout(unsigned long data)
586 {
587 struct llc_shdlc *shdlc = (struct llc_shdlc *)data;
588
589 pr_debug("\n");
590
591 schedule_work(&shdlc->sm_work);
592 }
593
594 static void llc_shdlc_t1_timeout(unsigned long data)
595 {
596 struct llc_shdlc *shdlc = (struct llc_shdlc *)data;
597
598 pr_debug("SoftIRQ: need to send ack\n");
599
600 schedule_work(&shdlc->sm_work);
601 }
602
603 static void llc_shdlc_t2_timeout(unsigned long data)
604 {
605 struct llc_shdlc *shdlc = (struct llc_shdlc *)data;
606
607 pr_debug("SoftIRQ: need to retransmit\n");
608
609 schedule_work(&shdlc->sm_work);
610 }
611
612 static void llc_shdlc_sm_work(struct work_struct *work)
613 {
614 struct llc_shdlc *shdlc = container_of(work, struct llc_shdlc, sm_work);
615 int r;
616
617 pr_debug("\n");
618
619 mutex_lock(&shdlc->state_mutex);
620
621 switch (shdlc->state) {
622 case SHDLC_DISCONNECTED:
623 skb_queue_purge(&shdlc->rcv_q);
624 skb_queue_purge(&shdlc->send_q);
625 skb_queue_purge(&shdlc->ack_pending_q);
626 break;
627 case SHDLC_CONNECTING:
628 if (shdlc->hard_fault) {
629 llc_shdlc_connect_complete(shdlc, shdlc->hard_fault);
630 break;
631 }
632
633 if (shdlc->connect_tries++ < 5)
634 r = llc_shdlc_connect_initiate(shdlc);
635 else
636 r = -ETIME;
637 if (r < 0) {
638 llc_shdlc_connect_complete(shdlc, r);
639 } else {
640 mod_timer(&shdlc->connect_timer, jiffies +
641 msecs_to_jiffies(SHDLC_CONNECT_VALUE_MS));
642
643 shdlc->state = SHDLC_NEGOTIATING;
644 }
645 break;
646 case SHDLC_NEGOTIATING:
647 if (timer_pending(&shdlc->connect_timer) == 0) {
648 shdlc->state = SHDLC_CONNECTING;
649 schedule_work(&shdlc->sm_work);
650 }
651
652 llc_shdlc_handle_rcv_queue(shdlc);
653
654 if (shdlc->hard_fault) {
655 llc_shdlc_connect_complete(shdlc, shdlc->hard_fault);
656 break;
657 }
658 break;
659 case SHDLC_HALF_CONNECTED:
660 case SHDLC_CONNECTED:
661 llc_shdlc_handle_rcv_queue(shdlc);
662 llc_shdlc_handle_send_queue(shdlc);
663
664 if (shdlc->t1_active && timer_pending(&shdlc->t1_timer) == 0) {
665 pr_debug
666 ("Handle T1(send ack) elapsed (T1 now inactive)\n");
667
668 shdlc->t1_active = false;
669 r = llc_shdlc_send_s_frame(shdlc, S_FRAME_RR,
670 shdlc->nr);
671 if (r < 0)
672 shdlc->hard_fault = r;
673 }
674
675 if (shdlc->t2_active && timer_pending(&shdlc->t2_timer) == 0) {
676 pr_debug
677 ("Handle T2(retransmit) elapsed (T2 inactive)\n");
678
679 shdlc->t2_active = false;
680
681 llc_shdlc_requeue_ack_pending(shdlc);
682 llc_shdlc_handle_send_queue(shdlc);
683 }
684
685 if (shdlc->hard_fault)
686 shdlc->llc_failure(shdlc->hdev, shdlc->hard_fault);
687 break;
688 default:
689 break;
690 }
691 mutex_unlock(&shdlc->state_mutex);
692 }
693
694 /*
695 * Called from syscall context to establish shdlc link. Sleeps until
696 * link is ready or failure.
697 */
698 static int llc_shdlc_connect(struct llc_shdlc *shdlc)
699 {
700 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(connect_wq);
701
702 pr_debug("\n");
703
704 mutex_lock(&shdlc->state_mutex);
705
706 shdlc->state = SHDLC_CONNECTING;
707 shdlc->connect_wq = &connect_wq;
708 shdlc->connect_tries = 0;
709 shdlc->connect_result = 1;
710
711 mutex_unlock(&shdlc->state_mutex);
712
713 schedule_work(&shdlc->sm_work);
714
715 wait_event(connect_wq, shdlc->connect_result != 1);
716
717 return shdlc->connect_result;
718 }
719
720 static void llc_shdlc_disconnect(struct llc_shdlc *shdlc)
721 {
722 pr_debug("\n");
723
724 mutex_lock(&shdlc->state_mutex);
725
726 shdlc->state = SHDLC_DISCONNECTED;
727
728 mutex_unlock(&shdlc->state_mutex);
729
730 schedule_work(&shdlc->sm_work);
731 }
732
733 /*
734 * Receive an incoming shdlc frame. Frame has already been crc-validated.
735 * skb contains only LLC header and payload.
736 * If skb == NULL, it is a notification that the link below is dead.
737 */
738 static void llc_shdlc_recv_frame(struct llc_shdlc *shdlc, struct sk_buff *skb)
739 {
740 if (skb == NULL) {
741 pr_err("NULL Frame -> link is dead\n");
742 shdlc->hard_fault = -EREMOTEIO;
743 } else {
744 SHDLC_DUMP_SKB("incoming frame", skb);
745 skb_queue_tail(&shdlc->rcv_q, skb);
746 }
747
748 schedule_work(&shdlc->sm_work);
749 }
750
751 static void *llc_shdlc_init(struct nfc_hci_dev *hdev, xmit_to_drv_t xmit_to_drv,
752 rcv_to_hci_t rcv_to_hci, int tx_headroom,
753 int tx_tailroom, int *rx_headroom, int *rx_tailroom,
754 llc_failure_t llc_failure)
755 {
756 struct llc_shdlc *shdlc;
757
758 *rx_headroom = SHDLC_LLC_HEAD_ROOM;
759 *rx_tailroom = 0;
760
761 shdlc = kzalloc(sizeof(struct llc_shdlc), GFP_KERNEL);
762 if (shdlc == NULL)
763 return NULL;
764
765 mutex_init(&shdlc->state_mutex);
766 shdlc->state = SHDLC_DISCONNECTED;
767
768 init_timer(&shdlc->connect_timer);
769 shdlc->connect_timer.data = (unsigned long)shdlc;
770 shdlc->connect_timer.function = llc_shdlc_connect_timeout;
771
772 init_timer(&shdlc->t1_timer);
773 shdlc->t1_timer.data = (unsigned long)shdlc;
774 shdlc->t1_timer.function = llc_shdlc_t1_timeout;
775
776 init_timer(&shdlc->t2_timer);
777 shdlc->t2_timer.data = (unsigned long)shdlc;
778 shdlc->t2_timer.function = llc_shdlc_t2_timeout;
779
780 shdlc->w = SHDLC_MAX_WINDOW;
781 shdlc->srej_support = SHDLC_SREJ_SUPPORT;
782
783 skb_queue_head_init(&shdlc->rcv_q);
784 skb_queue_head_init(&shdlc->send_q);
785 skb_queue_head_init(&shdlc->ack_pending_q);
786
787 INIT_WORK(&shdlc->sm_work, llc_shdlc_sm_work);
788
789 shdlc->hdev = hdev;
790 shdlc->xmit_to_drv = xmit_to_drv;
791 shdlc->rcv_to_hci = rcv_to_hci;
792 shdlc->tx_headroom = tx_headroom;
793 shdlc->tx_tailroom = tx_tailroom;
794 shdlc->llc_failure = llc_failure;
795
796 return shdlc;
797 }
798
799 static void llc_shdlc_deinit(struct nfc_llc *llc)
800 {
801 struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
802
803 skb_queue_purge(&shdlc->rcv_q);
804 skb_queue_purge(&shdlc->send_q);
805 skb_queue_purge(&shdlc->ack_pending_q);
806
807 kfree(shdlc);
808 }
809
810 static int llc_shdlc_start(struct nfc_llc *llc)
811 {
812 struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
813
814 return llc_shdlc_connect(shdlc);
815 }
816
817 static int llc_shdlc_stop(struct nfc_llc *llc)
818 {
819 struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
820
821 llc_shdlc_disconnect(shdlc);
822
823 return 0;
824 }
825
826 static void llc_shdlc_rcv_from_drv(struct nfc_llc *llc, struct sk_buff *skb)
827 {
828 struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
829
830 llc_shdlc_recv_frame(shdlc, skb);
831 }
832
833 static int llc_shdlc_xmit_from_hci(struct nfc_llc *llc, struct sk_buff *skb)
834 {
835 struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
836
837 skb_queue_tail(&shdlc->send_q, skb);
838
839 schedule_work(&shdlc->sm_work);
840
841 return 0;
842 }
843
844 static struct nfc_llc_ops llc_shdlc_ops = {
845 .init = llc_shdlc_init,
846 .deinit = llc_shdlc_deinit,
847 .start = llc_shdlc_start,
848 .stop = llc_shdlc_stop,
849 .rcv_from_drv = llc_shdlc_rcv_from_drv,
850 .xmit_from_hci = llc_shdlc_xmit_from_hci,
851 };
852
853 int nfc_llc_shdlc_register(void)
854 {
855 return nfc_llc_register(LLC_SHDLC_NAME, &llc_shdlc_ops);
856 }
CRIS linux kernel tree