aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/bluetooth/hci_ll.c
blob: 69a90b1b5ff56131aa7a2e51b7d18aabba28b560 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
/*
 *  Texas Instruments' Bluetooth HCILL UART protocol
 *
 *  HCILL (HCI Low Level) is a Texas Instruments' power management
 *  protocol extension to H4.
 *
 *  Copyright (C) 2007 Texas Instruments, Inc.
 *
 *  Written by Ohad Ben-Cohen <ohad@bencohen.org>
 *
 *  Acknowledgements:
 *  This file is based on hci_h4.c, which was written
 *  by Maxim Krasnyansky and Marcel Holtmann.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>

#include <linux/init.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/poll.h>

#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/signal.h>
#include <linux/ioctl.h>
#include <linux/skbuff.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>

#include "hci_uart.h"

/* HCILL commands */
#define HCILL_GO_TO_SLEEP_IND	0x30
#define HCILL_GO_TO_SLEEP_ACK	0x31
#define HCILL_WAKE_UP_IND	0x32
#define HCILL_WAKE_UP_ACK	0x33

/* HCILL receiver States */
#define HCILL_W4_PACKET_TYPE	0
#define HCILL_W4_EVENT_HDR	1
#define HCILL_W4_ACL_HDR	2
#define HCILL_W4_SCO_HDR	3
#define HCILL_W4_DATA		4

/* HCILL states */
enum hcill_states_e {
	HCILL_ASLEEP,
	HCILL_ASLEEP_TO_AWAKE,
	HCILL_AWAKE,
	HCILL_AWAKE_TO_ASLEEP
};

struct hcill_cmd {
	u8 cmd;
} __packed;

struct ll_struct {
	unsigned long rx_state;
	unsigned long rx_count;
	struct sk_buff *rx_skb;
	struct sk_buff_head txq;
	spinlock_t hcill_lock;		/* HCILL state lock	*/
	unsigned long hcill_state;	/* HCILL power state	*/
	struct sk_buff_head tx_wait_q;	/* HCILL wait queue	*/
};

/*
 * Builds and sends an HCILL command packet.
 * These are very simple packets with only 1 cmd byte
 */
static int send_hcill_cmd(u8 cmd, struct hci_uart *hu)
{
	int err = 0;
	struct sk_buff *skb = NULL;
	struct ll_struct *ll = hu->priv;
	struct hcill_cmd *hcill_packet;

	BT_DBG("hu %p cmd 0x%x", hu, cmd);

	/* allocate packet */
	skb = bt_skb_alloc(1, GFP_ATOMIC);
	if (!skb) {
		BT_ERR("cannot allocate memory for HCILL packet");
		err = -ENOMEM;
		goto out;
	}

	/* prepare packet */
	hcill_packet = (struct hcill_cmd *) skb_put(skb, 1);
	hcill_packet->cmd = cmd;

	/* send packet */
	skb_queue_tail(&ll->txq, skb);
out:
	return err;
}

/* Initialize protocol */
static int ll_open(struct hci_uart *hu)
{
	struct ll_struct *ll;

	BT_DBG("hu %p", hu);

	ll = kzalloc(sizeof(*ll), GFP_KERNEL);
	if (!ll)
		return -ENOMEM;

	skb_queue_head_init(&ll->txq);
	skb_queue_head_init(&ll->tx_wait_q);
	spin_lock_init(&ll->hcill_lock);

	ll->hcill_state = HCILL_AWAKE;

	hu->priv = ll;

	return 0;
}

/* Flush protocol data */
static int ll_flush(struct hci_uart *hu)
{
	struct ll_struct *ll = hu->priv;

	BT_DBG("hu %p", hu);

	skb_queue_purge(&ll->tx_wait_q);
	skb_queue_purge(&ll->txq);

	return 0;
}

/* Close protocol */
static int ll_close(struct hci_uart *hu)
{
	struct ll_struct *ll = hu->priv;

	BT_DBG("hu %p", hu);

	skb_queue_purge(&ll->tx_wait_q);
	skb_queue_purge(&ll->txq);

	kfree_skb(ll->rx_skb);

	hu->priv = NULL;

	kfree(ll);

	return 0;
}

/*
 * internal function, which does common work of the device wake up process:
 * 1. places all pending packets (waiting in tx_wait_q list) in txq list.
 * 2. changes internal state to HCILL_AWAKE.
 * Note: assumes that hcill_lock spinlock is taken,
 * shouldn't be called otherwise!
 */
static void __ll_do_awake(struct ll_struct *ll)
{
	struct sk_buff *skb = NULL;

	while ((skb = skb_dequeue(&ll->tx_wait_q)))
		skb_queue_tail(&ll->txq, skb);

	ll->hcill_state = HCILL_AWAKE;
}

/*
 * Called upon a wake-up-indication from the device
 */
static void ll_device_want_to_wakeup(struct hci_uart *hu)
{
	unsigned long flags;
	struct ll_struct *ll = hu->priv;

	BT_DBG("hu %p", hu);

	/* lock hcill state */
	spin_lock_irqsave(&ll->hcill_lock, flags);

	switch (ll->hcill_state) {
	case HCILL_ASLEEP_TO_AWAKE:
		/*
		 * This state means that both the host and the BRF chip
		 * have simultaneously sent a wake-up-indication packet.
		 * Traditionally, in this case, receiving a wake-up-indication
		 * was enough and an additional wake-up-ack wasn't needed.
		 * This has changed with the BRF6350, which does require an
		 * explicit wake-up-ack. Other BRF versions, which do not
		 * require an explicit ack here, do accept it, thus it is
		 * perfectly safe to always send one.
		 */
		BT_DBG("dual wake-up-indication");
		/* deliberate fall-through - do not add break */
	case HCILL_ASLEEP:
		/* acknowledge device wake up */
		if (send_hcill_cmd(HCILL_WAKE_UP_ACK, hu) < 0) {
			BT_ERR("cannot acknowledge device wake up");
			goto out;
		}
		break;
	default:
		/* any other state is illegal */
		BT_ERR("received HCILL_WAKE_UP_IND in state %ld", ll->hcill_state);
		break;
	}

	/* send pending packets and change state to HCILL_AWAKE */
	__ll_do_awake(ll);

out:
	spin_unlock_irqrestore(&ll->hcill_lock, flags);

	/* actually send the packets */
	hci_uart_tx_wakeup(hu);
}

/*
 * Called upon a sleep-indication from the device
 */
static void ll_device_want_to_sleep(struct hci_uart *hu)
{
	unsigned long flags;
	struct ll_struct *ll = hu->priv;

	BT_DBG("hu %p", hu);

	/* lock hcill state */
	spin_lock_irqsave(&ll->hcill_lock, flags);

	/* sanity check */
	if (ll->hcill_state != HCILL_AWAKE)
		BT_ERR("ERR: HCILL_GO_TO_SLEEP_IND in state %ld", ll->hcill_state);

	/* acknowledge device sleep */
	if (send_hcill_cmd(HCILL_GO_TO_SLEEP_ACK, hu) < 0) {
		BT_ERR("cannot acknowledge device sleep");
		goto out;
	}

	/* update state */
	ll->hcill_state = HCILL_ASLEEP;

out:
	spin_unlock_irqrestore(&ll->hcill_lock, flags);

	/* actually send the sleep ack packet */
	hci_uart_tx_wakeup(hu);
}

/*
 * Called upon wake-up-acknowledgement from the device
 */
static void ll_device_woke_up(struct hci_uart *hu)
{
	unsigned long flags;
	struct ll_struct *ll = hu->priv;

	BT_DBG("hu %p", hu);

	/* lock hcill state */
	spin_lock_irqsave(&ll->hcill_lock, flags);

	/* sanity check */
	if (ll->hcill_state != HCILL_ASLEEP_TO_AWAKE)
		BT_ERR("received HCILL_WAKE_UP_ACK in state %ld", ll->hcill_state);

	/* send pending packets and change state to HCILL_AWAKE */
	__ll_do_awake(ll);

	spin_unlock_irqrestore(&ll->hcill_lock, flags);

	/* actually send the packets */
	hci_uart_tx_wakeup(hu);
}

/* Enqueue frame for transmittion (padding, crc, etc) */
/* may be called from two simultaneous tasklets */
static int ll_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
	unsigned long flags = 0;
	struct ll_struct *ll = hu->priv;

	BT_DBG("hu %p skb %p", hu, skb);

	/* Prepend skb with frame type */
	memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);

	/* lock hcill state */
	spin_lock_irqsave(&ll->hcill_lock, flags);

	/* act according to current state */
	switch (ll->hcill_state) {
	case HCILL_AWAKE:
		BT_DBG("device awake, sending normally");
		skb_queue_tail(&ll->txq, skb);
		break;
	case HCILL_ASLEEP:
		BT_DBG("device asleep, waking up and queueing packet");
		/* save packet for later */
		skb_queue_tail(&ll->tx_wait_q, skb);
		/* awake device */
		if (send_hcill_cmd(HCILL_WAKE_UP_IND, hu) < 0) {
			BT_ERR("cannot wake up device");
			break;
		}
		ll->hcill_state = HCILL_ASLEEP_TO_AWAKE;
		break;
	case HCILL_ASLEEP_TO_AWAKE:
		BT_DBG("device waking up, queueing packet");
		/* transient state; just keep packet for later */
		skb_queue_tail(&ll->tx_wait_q, skb);
		break;
	default:
		BT_ERR("illegal hcill state: %ld (losing packet)", ll->hcill_state);
		kfree_skb(skb);
		break;
	}

	spin_unlock_irqrestore(&ll->hcill_lock, flags);

	return 0;
}

static inline int ll_check_data_len(struct hci_dev *hdev, struct ll_struct *ll, int len)
{
	int room = skb_tailroom(ll->rx_skb);

	BT_DBG("len %d room %d", len, room);

	if (!len) {
		hci_recv_frame(hdev, ll->rx_skb);
	} else if (len > room) {
		BT_ERR("Data length is too large");
		kfree_skb(ll->rx_skb);
	} else {
		ll->rx_state = HCILL_W4_DATA;
		ll->rx_count = len;
		return len;
	}

	ll->rx_state = HCILL_W4_PACKET_TYPE;
	ll->rx_skb   = NULL;
	ll->rx_count = 0;

	return 0;
}

/* Recv data */
static int ll_recv(struct hci_uart *hu, void *data, int count)
{
	struct ll_struct *ll = hu->priv;
	char *ptr;
	struct hci_event_hdr *eh;
	struct hci_acl_hdr   *ah;
	struct hci_sco_hdr   *sh;
	int len, type, dlen;

	BT_DBG("hu %p count %d rx_state %ld rx_count %ld", hu, count, ll->rx_state, ll->rx_count);

	ptr = data;
	while (count) {
		if (ll->rx_count) {
			len = min_t(unsigned int, ll->rx_count, count);
			memcpy(skb_put(ll->rx_skb, len), ptr, len);
			ll->rx_count -= len; count -= len; ptr += len;

			if (ll->rx_count)
				continue;

			switch (ll->rx_state) {
			case HCILL_W4_DATA:
				BT_DBG("Complete data");
				hci_recv_frame(hu->hdev, ll->rx_skb);

				ll->rx_state = HCILL_W4_PACKET_TYPE;
				ll->rx_skb = NULL;
				continue;

			case HCILL_W4_EVENT_HDR:
				eh = hci_event_hdr(ll->rx_skb);

				BT_DBG("Event header: evt 0x%2.2x plen %d", eh->evt, eh->plen);

				ll_check_data_len(hu->hdev, ll, eh->plen);
				continue;

			case HCILL_W4_ACL_HDR:
				ah = hci_acl_hdr(ll->rx_skb);
				dlen = __le16_to_cpu(ah->dlen);

				BT_DBG("ACL header: dlen %d", dlen);

				ll_check_data_len(hu->hdev, ll, dlen);
				continue;

			case HCILL_W4_SCO_HDR:
				sh = hci_sco_hdr(ll->rx_skb);

				BT_DBG("SCO header: dlen %d", sh->dlen);

				ll_check_data_len(hu->hdev, ll, sh->dlen);
				continue;
			}
		}

		/* HCILL_W4_PACKET_TYPE */
		switch (*ptr) {
		case HCI_EVENT_PKT:
			BT_DBG("Event packet");
			ll->rx_state = HCILL_W4_EVENT_HDR;
			ll->rx_count = HCI_EVENT_HDR_SIZE;
			type = HCI_EVENT_PKT;
			break;

		case HCI_ACLDATA_PKT:
			BT_DBG("ACL packet");
			ll->rx_state = HCILL_W4_ACL_HDR;
			ll->rx_count = HCI_ACL_HDR_SIZE;
			type = HCI_ACLDATA_PKT;
			break;

		case HCI_SCODATA_PKT:
			BT_DBG("SCO packet");
			ll->rx_state = HCILL_W4_SCO_HDR;
			ll->rx_count = HCI_SCO_HDR_SIZE;
			type = HCI_SCODATA_PKT;
			break;

		/* HCILL signals */
		case HCILL_GO_TO_SLEEP_IND:
			BT_DBG("HCILL_GO_TO_SLEEP_IND packet");
			ll_device_want_to_sleep(hu);
			ptr++; count--;
			continue;

		case HCILL_GO_TO_SLEEP_ACK:
			/* shouldn't happen */
			BT_ERR("received HCILL_GO_TO_SLEEP_ACK (in state %ld)", ll->hcill_state);
			ptr++; count--;
			continue;

		case HCILL_WAKE_UP_IND:
			BT_DBG("HCILL_WAKE_UP_IND packet");
			ll_device_want_to_wakeup(hu);
			ptr++; count--;
			continue;

		case HCILL_WAKE_UP_ACK:
			BT_DBG("HCILL_WAKE_UP_ACK packet");
			ll_device_woke_up(hu);
			ptr++; count--;
			continue;

		default:
			BT_ERR("Unknown HCI packet type %2.2x", (__u8)*ptr);
			hu->hdev->stat.err_rx++;
			ptr++; count--;
			continue;
		}

		ptr++; count--;

		/* Allocate packet */
		ll->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);
		if (!ll->rx_skb) {
			BT_ERR("Can't allocate mem for new packet");
			ll->rx_state = HCILL_W4_PACKET_TYPE;
			ll->rx_count = 0;
			return -ENOMEM;
		}

		bt_cb(ll->rx_skb)->pkt_type = type;
	}

	return count;
}

static struct sk_buff *ll_dequeue(struct hci_uart *hu)
{
	struct ll_struct *ll = hu->priv;
	return skb_dequeue(&ll->txq);
}

static struct hci_uart_proto llp = {
	.id		= HCI_UART_LL,
	.open		= ll_open,
	.close		= ll_close,
	.recv		= ll_recv,
	.enqueue	= ll_enqueue,
	.dequeue	= ll_dequeue,
	.flush		= ll_flush,
};

int __init ll_init(void)
{
	int err = hci_uart_register_proto(&llp);

	if (!err)
		BT_INFO("HCILL protocol initialized");
	else
		BT_ERR("HCILL protocol registration failed");

	return err;
}

int __exit ll_deinit(void)
{
	return hci_uart_unregister_proto(&llp);
}