1 /*
2 * Texas Instruments' Bluetooth HCILL UART protocol
3 *
4 * HCILL (HCI Low Level) is a Texas Instruments' power management
5 * protocol extension to H4.
6 *
7 * Copyright (C) 2007 Texas Instruments, Inc.
8 *
9 * Written by Ohad Ben-Cohen <ohad@bencohen.org>
10 *
11 * Acknowledgements:
12 * This file is based on hci_h4.c, which was written
13 * by Maxim Krasnyansky and Marcel Holtmann.
14 *
15 * This program is free software; you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License version 2
17 * as published by the Free Software Foundation
18 *
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, write to the Free Software
26 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
27 *
28 */
29
30 #include <linux/module.h>
31 #include <linux/kernel.h>
32
33 #include <linux/init.h>
34 #include <linux/sched.h>
35 #include <linux/types.h>
36 #include <linux/fcntl.h>
37 #include <linux/interrupt.h>
38 #include <linux/ptrace.h>
39 #include <linux/poll.h>
40
41 #include <linux/slab.h>
42 #include <linux/tty.h>
43 #include <linux/errno.h>
44 #include <linux/string.h>
45 #include <linux/signal.h>
46 #include <linux/ioctl.h>
47 #include <linux/skbuff.h>
48
49 #include <net/bluetooth/bluetooth.h>
50 #include <net/bluetooth/hci_core.h>
51
52 #include "hci_uart.h"
53
54 /* HCILL commands */
55 #define HCILL_GO_TO_SLEEP_IND 0x30
56 #define HCILL_GO_TO_SLEEP_ACK 0x31
57 #define HCILL_WAKE_UP_IND 0x32
58 #define HCILL_WAKE_UP_ACK 0x33
59
60 /* HCILL receiver States */
61 #define HCILL_W4_PACKET_TYPE 0
62 #define HCILL_W4_EVENT_HDR 1
63 #define HCILL_W4_ACL_HDR 2
64 #define HCILL_W4_SCO_HDR 3
65 #define HCILL_W4_DATA 4
66
67 /* HCILL states */
68 enum hcill_states_e {
69 HCILL_ASLEEP,
70 HCILL_ASLEEP_TO_AWAKE,
71 HCILL_AWAKE,
72 HCILL_AWAKE_TO_ASLEEP
73 };
74
75 struct hcill_cmd {
76 u8 cmd;
77 } __packed;
78
79 struct ll_struct {
80 unsigned long rx_state;
81 unsigned long rx_count;
82 struct sk_buff *rx_skb;
83 struct sk_buff_head txq;
84 spinlock_t hcill_lock; /* HCILL state lock */
85 unsigned long hcill_state; /* HCILL power state */
86 struct sk_buff_head tx_wait_q; /* HCILL wait queue */
87 };
88
89 /*
90 * Builds and sends an HCILL command packet.
91 * These are very simple packets with only 1 cmd byte
92 */
send_hcill_cmd(u8 cmd,struct hci_uart * hu)93 static int send_hcill_cmd(u8 cmd, struct hci_uart *hu)
94 {
95 int err = 0;
96 struct sk_buff *skb = NULL;
97 struct ll_struct *ll = hu->priv;
98 struct hcill_cmd *hcill_packet;
99
100 BT_DBG("hu %p cmd 0x%x", hu, cmd);
101
102 /* allocate packet */
103 skb = bt_skb_alloc(1, GFP_ATOMIC);
104 if (!skb) {
105 BT_ERR("cannot allocate memory for HCILL packet");
106 err = -ENOMEM;
107 goto out;
108 }
109
110 /* prepare packet */
111 hcill_packet = (struct hcill_cmd *) skb_put(skb, 1);
112 hcill_packet->cmd = cmd;
113 skb->dev = (void *) hu->hdev;
114
115 /* send packet */
116 skb_queue_tail(&ll->txq, skb);
117 out:
118 return err;
119 }
120
121 /* Initialize protocol */
ll_open(struct hci_uart * hu)122 static int ll_open(struct hci_uart *hu)
123 {
124 struct ll_struct *ll;
125
126 BT_DBG("hu %p", hu);
127
128 ll = kzalloc(sizeof(*ll), GFP_KERNEL);
129 if (!ll)
130 return -ENOMEM;
131
132 skb_queue_head_init(&ll->txq);
133 skb_queue_head_init(&ll->tx_wait_q);
134 spin_lock_init(&ll->hcill_lock);
135
136 ll->hcill_state = HCILL_AWAKE;
137
138 hu->priv = ll;
139
140 return 0;
141 }
142
143 /* Flush protocol data */
ll_flush(struct hci_uart * hu)144 static int ll_flush(struct hci_uart *hu)
145 {
146 struct ll_struct *ll = hu->priv;
147
148 BT_DBG("hu %p", hu);
149
150 skb_queue_purge(&ll->tx_wait_q);
151 skb_queue_purge(&ll->txq);
152
153 return 0;
154 }
155
156 /* Close protocol */
ll_close(struct hci_uart * hu)157 static int ll_close(struct hci_uart *hu)
158 {
159 struct ll_struct *ll = hu->priv;
160
161 BT_DBG("hu %p", hu);
162
163 skb_queue_purge(&ll->tx_wait_q);
164 skb_queue_purge(&ll->txq);
165
166 kfree_skb(ll->rx_skb);
167
168 hu->priv = NULL;
169
170 kfree(ll);
171
172 return 0;
173 }
174
175 /*
176 * internal function, which does common work of the device wake up process:
177 * 1. places all pending packets (waiting in tx_wait_q list) in txq list.
178 * 2. changes internal state to HCILL_AWAKE.
179 * Note: assumes that hcill_lock spinlock is taken,
180 * shouldn't be called otherwise!
181 */
__ll_do_awake(struct ll_struct * ll)182 static void __ll_do_awake(struct ll_struct *ll)
183 {
184 struct sk_buff *skb = NULL;
185
186 while ((skb = skb_dequeue(&ll->tx_wait_q)))
187 skb_queue_tail(&ll->txq, skb);
188
189 ll->hcill_state = HCILL_AWAKE;
190 }
191
192 /*
193 * Called upon a wake-up-indication from the device
194 */
ll_device_want_to_wakeup(struct hci_uart * hu)195 static void ll_device_want_to_wakeup(struct hci_uart *hu)
196 {
197 unsigned long flags;
198 struct ll_struct *ll = hu->priv;
199
200 BT_DBG("hu %p", hu);
201
202 /* lock hcill state */
203 spin_lock_irqsave(&ll->hcill_lock, flags);
204
205 switch (ll->hcill_state) {
206 case HCILL_ASLEEP_TO_AWAKE:
207 /*
208 * This state means that both the host and the BRF chip
209 * have simultaneously sent a wake-up-indication packet.
210 * Traditionally, in this case, receiving a wake-up-indication
211 * was enough and an additional wake-up-ack wasn't needed.
212 * This has changed with the BRF6350, which does require an
213 * explicit wake-up-ack. Other BRF versions, which do not
214 * require an explicit ack here, do accept it, thus it is
215 * perfectly safe to always send one.
216 */
217 BT_DBG("dual wake-up-indication");
218 /* deliberate fall-through - do not add break */
219 case HCILL_ASLEEP:
220 /* acknowledge device wake up */
221 if (send_hcill_cmd(HCILL_WAKE_UP_ACK, hu) < 0) {
222 BT_ERR("cannot acknowledge device wake up");
223 goto out;
224 }
225 break;
226 default:
227 /* any other state is illegal */
228 BT_ERR("received HCILL_WAKE_UP_IND in state %ld", ll->hcill_state);
229 break;
230 }
231
232 /* send pending packets and change state to HCILL_AWAKE */
233 __ll_do_awake(ll);
234
235 out:
236 spin_unlock_irqrestore(&ll->hcill_lock, flags);
237
238 /* actually send the packets */
239 hci_uart_tx_wakeup(hu);
240 }
241
242 /*
243 * Called upon a sleep-indication from the device
244 */
ll_device_want_to_sleep(struct hci_uart * hu)245 static void ll_device_want_to_sleep(struct hci_uart *hu)
246 {
247 unsigned long flags;
248 struct ll_struct *ll = hu->priv;
249
250 BT_DBG("hu %p", hu);
251
252 /* lock hcill state */
253 spin_lock_irqsave(&ll->hcill_lock, flags);
254
255 /* sanity check */
256 if (ll->hcill_state != HCILL_AWAKE)
257 BT_ERR("ERR: HCILL_GO_TO_SLEEP_IND in state %ld", ll->hcill_state);
258
259 /* acknowledge device sleep */
260 if (send_hcill_cmd(HCILL_GO_TO_SLEEP_ACK, hu) < 0) {
261 BT_ERR("cannot acknowledge device sleep");
262 goto out;
263 }
264
265 /* update state */
266 ll->hcill_state = HCILL_ASLEEP;
267
268 out:
269 spin_unlock_irqrestore(&ll->hcill_lock, flags);
270
271 /* actually send the sleep ack packet */
272 hci_uart_tx_wakeup(hu);
273 }
274
275 /*
276 * Called upon wake-up-acknowledgement from the device
277 */
ll_device_woke_up(struct hci_uart * hu)278 static void ll_device_woke_up(struct hci_uart *hu)
279 {
280 unsigned long flags;
281 struct ll_struct *ll = hu->priv;
282
283 BT_DBG("hu %p", hu);
284
285 /* lock hcill state */
286 spin_lock_irqsave(&ll->hcill_lock, flags);
287
288 /* sanity check */
289 if (ll->hcill_state != HCILL_ASLEEP_TO_AWAKE)
290 BT_ERR("received HCILL_WAKE_UP_ACK in state %ld", ll->hcill_state);
291
292 /* send pending packets and change state to HCILL_AWAKE */
293 __ll_do_awake(ll);
294
295 spin_unlock_irqrestore(&ll->hcill_lock, flags);
296
297 /* actually send the packets */
298 hci_uart_tx_wakeup(hu);
299 }
300
301 /* Enqueue frame for transmittion (padding, crc, etc) */
302 /* may be called from two simultaneous tasklets */
ll_enqueue(struct hci_uart * hu,struct sk_buff * skb)303 static int ll_enqueue(struct hci_uart *hu, struct sk_buff *skb)
304 {
305 unsigned long flags = 0;
306 struct ll_struct *ll = hu->priv;
307
308 BT_DBG("hu %p skb %p", hu, skb);
309
310 /* Prepend skb with frame type */
311 memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
312
313 /* lock hcill state */
314 spin_lock_irqsave(&ll->hcill_lock, flags);
315
316 /* act according to current state */
317 switch (ll->hcill_state) {
318 case HCILL_AWAKE:
319 BT_DBG("device awake, sending normally");
320 skb_queue_tail(&ll->txq, skb);
321 break;
322 case HCILL_ASLEEP:
323 BT_DBG("device asleep, waking up and queueing packet");
324 /* save packet for later */
325 skb_queue_tail(&ll->tx_wait_q, skb);
326 /* awake device */
327 if (send_hcill_cmd(HCILL_WAKE_UP_IND, hu) < 0) {
328 BT_ERR("cannot wake up device");
329 break;
330 }
331 ll->hcill_state = HCILL_ASLEEP_TO_AWAKE;
332 break;
333 case HCILL_ASLEEP_TO_AWAKE:
334 BT_DBG("device waking up, queueing packet");
335 /* transient state; just keep packet for later */
336 skb_queue_tail(&ll->tx_wait_q, skb);
337 break;
338 default:
339 BT_ERR("illegal hcill state: %ld (losing packet)", ll->hcill_state);
340 kfree_skb(skb);
341 break;
342 }
343
344 spin_unlock_irqrestore(&ll->hcill_lock, flags);
345
346 return 0;
347 }
348
ll_check_data_len(struct ll_struct * ll,int len)349 static inline int ll_check_data_len(struct ll_struct *ll, int len)
350 {
351 register int room = skb_tailroom(ll->rx_skb);
352
353 BT_DBG("len %d room %d", len, room);
354
355 if (!len) {
356 hci_recv_frame(ll->rx_skb);
357 } else if (len > room) {
358 BT_ERR("Data length is too large");
359 kfree_skb(ll->rx_skb);
360 } else {
361 ll->rx_state = HCILL_W4_DATA;
362 ll->rx_count = len;
363 return len;
364 }
365
366 ll->rx_state = HCILL_W4_PACKET_TYPE;
367 ll->rx_skb = NULL;
368 ll->rx_count = 0;
369
370 return 0;
371 }
372
373 /* Recv data */
ll_recv(struct hci_uart * hu,void * data,int count)374 static int ll_recv(struct hci_uart *hu, void *data, int count)
375 {
376 struct ll_struct *ll = hu->priv;
377 register char *ptr;
378 struct hci_event_hdr *eh;
379 struct hci_acl_hdr *ah;
380 struct hci_sco_hdr *sh;
381 register int len, type, dlen;
382
383 BT_DBG("hu %p count %d rx_state %ld rx_count %ld", hu, count, ll->rx_state, ll->rx_count);
384
385 ptr = data;
386 while (count) {
387 if (ll->rx_count) {
388 len = min_t(unsigned int, ll->rx_count, count);
389 memcpy(skb_put(ll->rx_skb, len), ptr, len);
390 ll->rx_count -= len; count -= len; ptr += len;
391
392 if (ll->rx_count)
393 continue;
394
395 switch (ll->rx_state) {
396 case HCILL_W4_DATA:
397 BT_DBG("Complete data");
398 hci_recv_frame(ll->rx_skb);
399
400 ll->rx_state = HCILL_W4_PACKET_TYPE;
401 ll->rx_skb = NULL;
402 continue;
403
404 case HCILL_W4_EVENT_HDR:
405 eh = hci_event_hdr(ll->rx_skb);
406
407 BT_DBG("Event header: evt 0x%2.2x plen %d", eh->evt, eh->plen);
408
409 ll_check_data_len(ll, eh->plen);
410 continue;
411
412 case HCILL_W4_ACL_HDR:
413 ah = hci_acl_hdr(ll->rx_skb);
414 dlen = __le16_to_cpu(ah->dlen);
415
416 BT_DBG("ACL header: dlen %d", dlen);
417
418 ll_check_data_len(ll, dlen);
419 continue;
420
421 case HCILL_W4_SCO_HDR:
422 sh = hci_sco_hdr(ll->rx_skb);
423
424 BT_DBG("SCO header: dlen %d", sh->dlen);
425
426 ll_check_data_len(ll, sh->dlen);
427 continue;
428 }
429 }
430
431 /* HCILL_W4_PACKET_TYPE */
432 switch (*ptr) {
433 case HCI_EVENT_PKT:
434 BT_DBG("Event packet");
435 ll->rx_state = HCILL_W4_EVENT_HDR;
436 ll->rx_count = HCI_EVENT_HDR_SIZE;
437 type = HCI_EVENT_PKT;
438 break;
439
440 case HCI_ACLDATA_PKT:
441 BT_DBG("ACL packet");
442 ll->rx_state = HCILL_W4_ACL_HDR;
443 ll->rx_count = HCI_ACL_HDR_SIZE;
444 type = HCI_ACLDATA_PKT;
445 break;
446
447 case HCI_SCODATA_PKT:
448 BT_DBG("SCO packet");
449 ll->rx_state = HCILL_W4_SCO_HDR;
450 ll->rx_count = HCI_SCO_HDR_SIZE;
451 type = HCI_SCODATA_PKT;
452 break;
453
454 /* HCILL signals */
455 case HCILL_GO_TO_SLEEP_IND:
456 BT_DBG("HCILL_GO_TO_SLEEP_IND packet");
457 ll_device_want_to_sleep(hu);
458 ptr++; count--;
459 continue;
460
461 case HCILL_GO_TO_SLEEP_ACK:
462 /* shouldn't happen */
463 BT_ERR("received HCILL_GO_TO_SLEEP_ACK (in state %ld)", ll->hcill_state);
464 ptr++; count--;
465 continue;
466
467 case HCILL_WAKE_UP_IND:
468 BT_DBG("HCILL_WAKE_UP_IND packet");
469 ll_device_want_to_wakeup(hu);
470 ptr++; count--;
471 continue;
472
473 case HCILL_WAKE_UP_ACK:
474 BT_DBG("HCILL_WAKE_UP_ACK packet");
475 ll_device_woke_up(hu);
476 ptr++; count--;
477 continue;
478
479 default:
480 BT_ERR("Unknown HCI packet type %2.2x", (__u8)*ptr);
481 hu->hdev->stat.err_rx++;
482 ptr++; count--;
483 continue;
484 };
485
486 ptr++; count--;
487
488 /* Allocate packet */
489 ll->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);
490 if (!ll->rx_skb) {
491 BT_ERR("Can't allocate mem for new packet");
492 ll->rx_state = HCILL_W4_PACKET_TYPE;
493 ll->rx_count = 0;
494 return -ENOMEM;
495 }
496
497 ll->rx_skb->dev = (void *) hu->hdev;
498 bt_cb(ll->rx_skb)->pkt_type = type;
499 }
500
501 return count;
502 }
503
ll_dequeue(struct hci_uart * hu)504 static struct sk_buff *ll_dequeue(struct hci_uart *hu)
505 {
506 struct ll_struct *ll = hu->priv;
507 return skb_dequeue(&ll->txq);
508 }
509
510 static struct hci_uart_proto llp = {
511 .id = HCI_UART_LL,
512 .open = ll_open,
513 .close = ll_close,
514 .recv = ll_recv,
515 .enqueue = ll_enqueue,
516 .dequeue = ll_dequeue,
517 .flush = ll_flush,
518 };
519
ll_init(void)520 int __init ll_init(void)
521 {
522 int err = hci_uart_register_proto(&llp);
523
524 if (!err)
525 BT_INFO("HCILL protocol initialized");
526 else
527 BT_ERR("HCILL protocol registration failed");
528
529 return err;
530 }
531
ll_deinit(void)532 int __exit ll_deinit(void)
533 {
534 return hci_uart_unregister_proto(&llp);
535 }
536