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Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
[deliverable/linux.git] / net / nfc / hci / llc_shdlc.c
CommitLineData
4a61cd66
EL		 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>
4a61cd66
EL		 25#include <linux/wait.h>
26#include <linux/slab.h>
27#include <linux/skbuff.h>
28
29#include "llc.h"
30
31enum shdlc_state {
32 SHDLC_DISCONNECTED = 0,
33 SHDLC_CONNECTING = 1,
4c0ba9ac 34 SHDLC_NEGOTIATING = 2,
12bfd1e8
WR		 35 SHDLC_HALF_CONNECTED = 3,
36 SHDLC_CONNECTED = 4
4a61cd66
EL		 37};
38
39struct 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
98enum sframe_type {
99 S_FRAME_RR = 0x00,
100 S_FRAME_REJ = 0x01,
101 S_FRAME_RNR = 0x02,
102 S_FRAME_SREJ = 0x03
103};
104
105enum 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) \
115do { \
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 */
122static 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 */
131static 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
139static 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. */
153static 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 */
175static 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 */
196static 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 */
236static 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
272exit:
273 kfree_skb(skb);
274}
275
276static 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
286static 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
299static 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 */
324static 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
356static 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
12bfd1e8 367 shdlc->state = SHDLC_HALF_CONNECTED;
4a61cd66
EL		 368 } else {
369 shdlc->state = SHDLC_DISCONNECTED;
370 }
371
372 shdlc->connect_result = r;
373
374 wake_up(shdlc->connect_wq);
375}
376
377static 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
393static 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
406static 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:
12bfd1e8 418 switch (shdlc->state) {
4c0ba9ac 419 case SHDLC_NEGOTIATING:
12bfd1e8
WR		 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 */
4a61cd66
EL		 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 }
12bfd1e8
WR		 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:
4a61cd66
EL		 447 /*
448 * Chip wants to reset link. This is unexpected and
449 * unsupported.
450 */
451 shdlc->hard_fault = -ECONNRESET;
12bfd1e8
WR		 452 break;
453 default:
454 break;
4a61cd66
EL		 455 }
456 break;
457 case U_FRAME_UA:
458 if ((shdlc->state == SHDLC_CONNECTING &&
459 shdlc->connect_tries > 0) ||
4c0ba9ac 460 (shdlc->state == SHDLC_NEGOTIATING)) {
4a61cd66 461 llc_shdlc_connect_complete(shdlc, 0);
12bfd1e8
WR		 462 shdlc->state = SHDLC_CONNECTED;
463 }
4a61cd66
EL		 464 break;
465 default:
466 break;
467 }
468
469 kfree_skb(skb);
470}
471
472static 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:
12bfd1e8
WR		 490 if (shdlc->state == SHDLC_HALF_CONNECTED)
491 shdlc->state = SHDLC_CONNECTED;
492
4a61cd66
EL		 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:
12bfd1e8
WR		 498 if (shdlc->state == SHDLC_HALF_CONNECTED)
499 shdlc->state = SHDLC_CONNECTED;
500
4a61cd66
EL		 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
518static 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 */
531static 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);
412fda53 561 SHDLC_DUMP_SKB("shdlc frame written", skb);
4a61cd66
EL		 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
585static 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 queue_work(system_nrt_wq, &shdlc->sm_work);
592}
593
594static 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 queue_work(system_nrt_wq, &shdlc->sm_work);
601}
602
603static 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 queue_work(system_nrt_wq, &shdlc->sm_work);
610}
611
612static 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
4c0ba9ac 643 shdlc->state = SHDLC_NEGOTIATING;
4a61cd66
EL		 644 }
645 break;
4c0ba9ac 646 case SHDLC_NEGOTIATING:
4a61cd66
EL		 647 if (timer_pending(&shdlc->connect_timer) == 0) {
648 shdlc->state = SHDLC_CONNECTING;
649 queue_work(system_nrt_wq, &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;
12bfd1e8 659 case SHDLC_HALF_CONNECTED:
4a61cd66
EL		 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 }
688 break;
689 default:
690 break;
691 }
692 mutex_unlock(&shdlc->state_mutex);
693}
694
695/*
696 * Called from syscall context to establish shdlc link. Sleeps until
697 * link is ready or failure.
698 */
699static int llc_shdlc_connect(struct llc_shdlc *shdlc)
700{
701 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(connect_wq);
702
703 pr_debug("\n");
704
705 mutex_lock(&shdlc->state_mutex);
706
707 shdlc->state = SHDLC_CONNECTING;
708 shdlc->connect_wq = &connect_wq;
709 shdlc->connect_tries = 0;
710 shdlc->connect_result = 1;
711
712 mutex_unlock(&shdlc->state_mutex);
713
714 queue_work(system_nrt_wq, &shdlc->sm_work);
715
716 wait_event(connect_wq, shdlc->connect_result != 1);
717
718 return shdlc->connect_result;
719}
720
721static void llc_shdlc_disconnect(struct llc_shdlc *shdlc)
722{
723 pr_debug("\n");
724
725 mutex_lock(&shdlc->state_mutex);
726
727 shdlc->state = SHDLC_DISCONNECTED;
728
729 mutex_unlock(&shdlc->state_mutex);
730
731 queue_work(system_nrt_wq, &shdlc->sm_work);
732}
733
734/*
735 * Receive an incoming shdlc frame. Frame has already been crc-validated.
736 * skb contains only LLC header and payload.
737 * If skb == NULL, it is a notification that the link below is dead.
738 */
739static void llc_shdlc_recv_frame(struct llc_shdlc *shdlc, struct sk_buff *skb)
740{
741 if (skb == NULL) {
742 pr_err("NULL Frame -> link is dead\n");
743 shdlc->hard_fault = -EREMOTEIO;
744 } else {
745 SHDLC_DUMP_SKB("incoming frame", skb);
746 skb_queue_tail(&shdlc->rcv_q, skb);
747 }
748
749 queue_work(system_nrt_wq, &shdlc->sm_work);
750}
751
752static void *llc_shdlc_init(struct nfc_hci_dev *hdev, xmit_to_drv_t xmit_to_drv,
753 rcv_to_hci_t rcv_to_hci, int tx_headroom,
754 int tx_tailroom, int *rx_headroom, int *rx_tailroom,
755 llc_failure_t llc_failure)
756{
757 struct llc_shdlc *shdlc;
758
759 *rx_headroom = SHDLC_LLC_HEAD_ROOM;
760 *rx_tailroom = 0;
761
762 shdlc = kzalloc(sizeof(struct llc_shdlc), GFP_KERNEL);
763 if (shdlc == NULL)
764 return NULL;
765
766 mutex_init(&shdlc->state_mutex);
767 shdlc->state = SHDLC_DISCONNECTED;
768
769 init_timer(&shdlc->connect_timer);
770 shdlc->connect_timer.data = (unsigned long)shdlc;
771 shdlc->connect_timer.function = llc_shdlc_connect_timeout;
772
773 init_timer(&shdlc->t1_timer);
774 shdlc->t1_timer.data = (unsigned long)shdlc;
775 shdlc->t1_timer.function = llc_shdlc_t1_timeout;
776
777 init_timer(&shdlc->t2_timer);
778 shdlc->t2_timer.data = (unsigned long)shdlc;
779 shdlc->t2_timer.function = llc_shdlc_t2_timeout;
780
781 shdlc->w = SHDLC_MAX_WINDOW;
782 shdlc->srej_support = SHDLC_SREJ_SUPPORT;
783
784 skb_queue_head_init(&shdlc->rcv_q);
785 skb_queue_head_init(&shdlc->send_q);
786 skb_queue_head_init(&shdlc->ack_pending_q);
787
788 INIT_WORK(&shdlc->sm_work, llc_shdlc_sm_work);
789
790 shdlc->hdev = hdev;
791 shdlc->xmit_to_drv = xmit_to_drv;
792 shdlc->rcv_to_hci = rcv_to_hci;
793 shdlc->tx_headroom = tx_headroom;
794 shdlc->tx_tailroom = tx_tailroom;
795 shdlc->llc_failure = llc_failure;
796
797 return shdlc;
798}
799
800static void llc_shdlc_deinit(struct nfc_llc *llc)
801{
802 struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
803
804 skb_queue_purge(&shdlc->rcv_q);
805 skb_queue_purge(&shdlc->send_q);
806 skb_queue_purge(&shdlc->ack_pending_q);
807
808 kfree(shdlc);
809}
810
811static int llc_shdlc_start(struct nfc_llc *llc)
812{
813 struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
814
815 return llc_shdlc_connect(shdlc);
816}
817
818static int llc_shdlc_stop(struct nfc_llc *llc)
819{
820 struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
821
822 llc_shdlc_disconnect(shdlc);
823
824 return 0;
825}
826
827static void llc_shdlc_rcv_from_drv(struct nfc_llc *llc, struct sk_buff *skb)
828{
829 struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
830
831 llc_shdlc_recv_frame(shdlc, skb);
832}
833
834static int llc_shdlc_xmit_from_hci(struct nfc_llc *llc, struct sk_buff *skb)
835{
836 struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
837
838 skb_queue_tail(&shdlc->send_q, skb);
839
840 queue_work(system_nrt_wq, &shdlc->sm_work);
841
842 return 0;
843}
844
845static struct nfc_llc_ops llc_shdlc_ops = {
846 .init = llc_shdlc_init,
847 .deinit = llc_shdlc_deinit,
848 .start = llc_shdlc_start,
849 .stop = llc_shdlc_stop,
850 .rcv_from_drv = llc_shdlc_rcv_from_drv,
851 .xmit_from_hci = llc_shdlc_xmit_from_hci,
852};
853
a7d0281b 854int nfc_llc_shdlc_register(void)
4a61cd66
EL		 855{
856 return nfc_llc_register(LLC_SHDLC_NAME, &llc_shdlc_ops);
857}
Linux kernel - Deliverables
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