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
114 /* send packet */
115 skb_queue_tail(&ll->txq, skb);
116 out:
117 return err;
118 }
119
120 /* Initialize protocol */
ll_open(struct hci_uart * hu)121 static int ll_open(struct hci_uart *hu)
122 {
123 struct ll_struct *ll;
124
125 BT_DBG("hu %p", hu);
126
127 ll = kzalloc(sizeof(*ll), GFP_KERNEL);
128 if (!ll)
129 return -ENOMEM;
130
131 skb_queue_head_init(&ll->txq);
132 skb_queue_head_init(&ll->tx_wait_q);
133 spin_lock_init(&ll->hcill_lock);
134
135 ll->hcill_state = HCILL_AWAKE;
136
137 hu->priv = ll;
138
139 return 0;
140 }
141
142 /* Flush protocol data */
ll_flush(struct hci_uart * hu)143 static int ll_flush(struct hci_uart *hu)
144 {
145 struct ll_struct *ll = hu->priv;
146
147 BT_DBG("hu %p", hu);
148
149 skb_queue_purge(&ll->tx_wait_q);
150 skb_queue_purge(&ll->txq);
151
152 return 0;
153 }
154
155 /* Close protocol */
ll_close(struct hci_uart * hu)156 static int ll_close(struct hci_uart *hu)
157 {
158 struct ll_struct *ll = hu->priv;
159
160 BT_DBG("hu %p", hu);
161
162 skb_queue_purge(&ll->tx_wait_q);
163 skb_queue_purge(&ll->txq);
164
165 kfree_skb(ll->rx_skb);
166
167 hu->priv = NULL;
168
169 kfree(ll);
170
171 return 0;
172 }
173
174 /*
175 * internal function, which does common work of the device wake up process:
176 * 1. places all pending packets (waiting in tx_wait_q list) in txq list.
177 * 2. changes internal state to HCILL_AWAKE.
178 * Note: assumes that hcill_lock spinlock is taken,
179 * shouldn't be called otherwise!
180 */
__ll_do_awake(struct ll_struct * ll)181 static void __ll_do_awake(struct ll_struct *ll)
182 {
183 struct sk_buff *skb = NULL;
184
185 while ((skb = skb_dequeue(&ll->tx_wait_q)))
186 skb_queue_tail(&ll->txq, skb);
187
188 ll->hcill_state = HCILL_AWAKE;
189 }
190
191 /*
192 * Called upon a wake-up-indication from the device
193 */
ll_device_want_to_wakeup(struct hci_uart * hu)194 static void ll_device_want_to_wakeup(struct hci_uart *hu)
195 {
196 unsigned long flags;
197 struct ll_struct *ll = hu->priv;
198
199 BT_DBG("hu %p", hu);
200
201 /* lock hcill state */
202 spin_lock_irqsave(&ll->hcill_lock, flags);
203
204 switch (ll->hcill_state) {
205 case HCILL_ASLEEP_TO_AWAKE:
206 /*
207 * This state means that both the host and the BRF chip
208 * have simultaneously sent a wake-up-indication packet.
209 * Traditionally, in this case, receiving a wake-up-indication
210 * was enough and an additional wake-up-ack wasn't needed.
211 * This has changed with the BRF6350, which does require an
212 * explicit wake-up-ack. Other BRF versions, which do not
213 * require an explicit ack here, do accept it, thus it is
214 * perfectly safe to always send one.
215 */
216 BT_DBG("dual wake-up-indication");
217 /* deliberate fall-through - do not add break */
218 case HCILL_ASLEEP:
219 /* acknowledge device wake up */
220 if (send_hcill_cmd(HCILL_WAKE_UP_ACK, hu) < 0) {
221 BT_ERR("cannot acknowledge device wake up");
222 goto out;
223 }
224 break;
225 default:
226 /* any other state is illegal */
227 BT_ERR("received HCILL_WAKE_UP_IND in state %ld", ll->hcill_state);
228 break;
229 }
230
231 /* send pending packets and change state to HCILL_AWAKE */
232 __ll_do_awake(ll);
233
234 out:
235 spin_unlock_irqrestore(&ll->hcill_lock, flags);
236
237 /* actually send the packets */
238 hci_uart_tx_wakeup(hu);
239 }
240
241 /*
242 * Called upon a sleep-indication from the device
243 */
ll_device_want_to_sleep(struct hci_uart * hu)244 static void ll_device_want_to_sleep(struct hci_uart *hu)
245 {
246 unsigned long flags;
247 struct ll_struct *ll = hu->priv;
248
249 BT_DBG("hu %p", hu);
250
251 /* lock hcill state */
252 spin_lock_irqsave(&ll->hcill_lock, flags);
253
254 /* sanity check */
255 if (ll->hcill_state != HCILL_AWAKE)
256 BT_ERR("ERR: HCILL_GO_TO_SLEEP_IND in state %ld", ll->hcill_state);
257
258 /* acknowledge device sleep */
259 if (send_hcill_cmd(HCILL_GO_TO_SLEEP_ACK, hu) < 0) {
260 BT_ERR("cannot acknowledge device sleep");
261 goto out;
262 }
263
264 /* update state */
265 ll->hcill_state = HCILL_ASLEEP;
266
267 out:
268 spin_unlock_irqrestore(&ll->hcill_lock, flags);
269
270 /* actually send the sleep ack packet */
271 hci_uart_tx_wakeup(hu);
272 }
273
274 /*
275 * Called upon wake-up-acknowledgement from the device
276 */
ll_device_woke_up(struct hci_uart * hu)277 static void ll_device_woke_up(struct hci_uart *hu)
278 {
279 unsigned long flags;
280 struct ll_struct *ll = hu->priv;
281
282 BT_DBG("hu %p", hu);
283
284 /* lock hcill state */
285 spin_lock_irqsave(&ll->hcill_lock, flags);
286
287 /* sanity check */
288 if (ll->hcill_state != HCILL_ASLEEP_TO_AWAKE)
289 BT_ERR("received HCILL_WAKE_UP_ACK in state %ld", ll->hcill_state);
290
291 /* send pending packets and change state to HCILL_AWAKE */
292 __ll_do_awake(ll);
293
294 spin_unlock_irqrestore(&ll->hcill_lock, flags);
295
296 /* actually send the packets */
297 hci_uart_tx_wakeup(hu);
298 }
299
300 /* Enqueue frame for transmittion (padding, crc, etc) */
301 /* may be called from two simultaneous tasklets */
ll_enqueue(struct hci_uart * hu,struct sk_buff * skb)302 static int ll_enqueue(struct hci_uart *hu, struct sk_buff *skb)
303 {
304 unsigned long flags = 0;
305 struct ll_struct *ll = hu->priv;
306
307 BT_DBG("hu %p skb %p", hu, skb);
308
309 /* Prepend skb with frame type */
310 memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
311
312 /* lock hcill state */
313 spin_lock_irqsave(&ll->hcill_lock, flags);
314
315 /* act according to current state */
316 switch (ll->hcill_state) {
317 case HCILL_AWAKE:
318 BT_DBG("device awake, sending normally");
319 skb_queue_tail(&ll->txq, skb);
320 break;
321 case HCILL_ASLEEP:
322 BT_DBG("device asleep, waking up and queueing packet");
323 /* save packet for later */
324 skb_queue_tail(&ll->tx_wait_q, skb);
325 /* awake device */
326 if (send_hcill_cmd(HCILL_WAKE_UP_IND, hu) < 0) {
327 BT_ERR("cannot wake up device");
328 break;
329 }
330 ll->hcill_state = HCILL_ASLEEP_TO_AWAKE;
331 break;
332 case HCILL_ASLEEP_TO_AWAKE:
333 BT_DBG("device waking up, queueing packet");
334 /* transient state; just keep packet for later */
335 skb_queue_tail(&ll->tx_wait_q, skb);
336 break;
337 default:
338 BT_ERR("illegal hcill state: %ld (losing packet)", ll->hcill_state);
339 kfree_skb(skb);
340 break;
341 }
342
343 spin_unlock_irqrestore(&ll->hcill_lock, flags);
344
345 return 0;
346 }
347
ll_check_data_len(struct hci_dev * hdev,struct ll_struct * ll,int len)348 static inline int ll_check_data_len(struct hci_dev *hdev, struct ll_struct *ll, int len)
349 {
350 int room = skb_tailroom(ll->rx_skb);
351
352 BT_DBG("len %d room %d", len, room);
353
354 if (!len) {
355 hci_recv_frame(hdev, ll->rx_skb);
356 } else if (len > room) {
357 BT_ERR("Data length is too large");
358 kfree_skb(ll->rx_skb);
359 } else {
360 ll->rx_state = HCILL_W4_DATA;
361 ll->rx_count = len;
362 return len;
363 }
364
365 ll->rx_state = HCILL_W4_PACKET_TYPE;
366 ll->rx_skb = NULL;
367 ll->rx_count = 0;
368
369 return 0;
370 }
371
372 /* Recv data */
ll_recv(struct hci_uart * hu,void * data,int count)373 static int ll_recv(struct hci_uart *hu, void *data, int count)
374 {
375 struct ll_struct *ll = hu->priv;
376 char *ptr;
377 struct hci_event_hdr *eh;
378 struct hci_acl_hdr *ah;
379 struct hci_sco_hdr *sh;
380 int len, type, dlen;
381
382 BT_DBG("hu %p count %d rx_state %ld rx_count %ld", hu, count, ll->rx_state, ll->rx_count);
383
384 ptr = data;
385 while (count) {
386 if (ll->rx_count) {
387 len = min_t(unsigned int, ll->rx_count, count);
388 memcpy(skb_put(ll->rx_skb, len), ptr, len);
389 ll->rx_count -= len; count -= len; ptr += len;
390
391 if (ll->rx_count)
392 continue;
393
394 switch (ll->rx_state) {
395 case HCILL_W4_DATA:
396 BT_DBG("Complete data");
397 hci_recv_frame(hu->hdev, ll->rx_skb);
398
399 ll->rx_state = HCILL_W4_PACKET_TYPE;
400 ll->rx_skb = NULL;
401 continue;
402
403 case HCILL_W4_EVENT_HDR:
404 eh = hci_event_hdr(ll->rx_skb);
405
406 BT_DBG("Event header: evt 0x%2.2x plen %d", eh->evt, eh->plen);
407
408 ll_check_data_len(hu->hdev, ll, eh->plen);
409 continue;
410
411 case HCILL_W4_ACL_HDR:
412 ah = hci_acl_hdr(ll->rx_skb);
413 dlen = __le16_to_cpu(ah->dlen);
414
415 BT_DBG("ACL header: dlen %d", dlen);
416
417 ll_check_data_len(hu->hdev, ll, dlen);
418 continue;
419
420 case HCILL_W4_SCO_HDR:
421 sh = hci_sco_hdr(ll->rx_skb);
422
423 BT_DBG("SCO header: dlen %d", sh->dlen);
424
425 ll_check_data_len(hu->hdev, ll, sh->dlen);
426 continue;
427 }
428 }
429
430 /* HCILL_W4_PACKET_TYPE */
431 switch (*ptr) {
432 case HCI_EVENT_PKT:
433 BT_DBG("Event packet");
434 ll->rx_state = HCILL_W4_EVENT_HDR;
435 ll->rx_count = HCI_EVENT_HDR_SIZE;
436 type = HCI_EVENT_PKT;
437 break;
438
439 case HCI_ACLDATA_PKT:
440 BT_DBG("ACL packet");
441 ll->rx_state = HCILL_W4_ACL_HDR;
442 ll->rx_count = HCI_ACL_HDR_SIZE;
443 type = HCI_ACLDATA_PKT;
444 break;
445
446 case HCI_SCODATA_PKT:
447 BT_DBG("SCO packet");
448 ll->rx_state = HCILL_W4_SCO_HDR;
449 ll->rx_count = HCI_SCO_HDR_SIZE;
450 type = HCI_SCODATA_PKT;
451 break;
452
453 /* HCILL signals */
454 case HCILL_GO_TO_SLEEP_IND:
455 BT_DBG("HCILL_GO_TO_SLEEP_IND packet");
456 ll_device_want_to_sleep(hu);
457 ptr++; count--;
458 continue;
459
460 case HCILL_GO_TO_SLEEP_ACK:
461 /* shouldn't happen */
462 BT_ERR("received HCILL_GO_TO_SLEEP_ACK (in state %ld)", ll->hcill_state);
463 ptr++; count--;
464 continue;
465
466 case HCILL_WAKE_UP_IND:
467 BT_DBG("HCILL_WAKE_UP_IND packet");
468 ll_device_want_to_wakeup(hu);
469 ptr++; count--;
470 continue;
471
472 case HCILL_WAKE_UP_ACK:
473 BT_DBG("HCILL_WAKE_UP_ACK packet");
474 ll_device_woke_up(hu);
475 ptr++; count--;
476 continue;
477
478 default:
479 BT_ERR("Unknown HCI packet type %2.2x", (__u8)*ptr);
480 hu->hdev->stat.err_rx++;
481 ptr++; count--;
482 continue;
483 }
484
485 ptr++; count--;
486
487 /* Allocate packet */
488 ll->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);
489 if (!ll->rx_skb) {
490 BT_ERR("Can't allocate mem for new packet");
491 ll->rx_state = HCILL_W4_PACKET_TYPE;
492 ll->rx_count = 0;
493 return -ENOMEM;
494 }
495
496 bt_cb(ll->rx_skb)->pkt_type = type;
497 }
498
499 return count;
500 }
501
ll_dequeue(struct hci_uart * hu)502 static struct sk_buff *ll_dequeue(struct hci_uart *hu)
503 {
504 struct ll_struct *ll = hu->priv;
505 return skb_dequeue(&ll->txq);
506 }
507
508 static struct hci_uart_proto llp = {
509 .id = HCI_UART_LL,
510 .open = ll_open,
511 .close = ll_close,
512 .recv = ll_recv,
513 .enqueue = ll_enqueue,
514 .dequeue = ll_dequeue,
515 .flush = ll_flush,
516 };
517
ll_init(void)518 int __init ll_init(void)
519 {
520 int err = hci_uart_register_proto(&llp);
521
522 if (!err)
523 BT_INFO("HCILL protocol initialized");
524 else
525 BT_ERR("HCILL protocol registration failed");
526
527 return err;
528 }
529
ll_deinit(void)530 int __exit ll_deinit(void)
531 {
532 return hci_uart_unregister_proto(&llp);
533 }
534