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Ohad Ben-Cohen166d2f62007-10-20 13:42:36 +02001/*
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 */
68enum hcill_states_e {
69 HCILL_ASLEEP,
70 HCILL_ASLEEP_TO_AWAKE,
71 HCILL_AWAKE,
72 HCILL_AWAKE_TO_ASLEEP
73};
74
75struct hcill_cmd {
76 u8 cmd;
77} __attribute__((packed));
78
79struct 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 */
93static 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);
117out:
118 return err;
119}
120
121/* Initialize protocol */
122static 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_ATOMIC);
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 */
144static 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 */
157static 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 if (ll->rx_skb)
167 kfree_skb(ll->rx_skb);
168
169 hu->priv = NULL;
170
171 kfree(ll);
172
173 return 0;
174}
175
176/*
177 * internal function, which does common work of the device wake up process:
178 * 1. places all pending packets (waiting in tx_wait_q list) in txq list.
179 * 2. changes internal state to HCILL_AWAKE.
180 * Note: assumes that hcill_lock spinlock is taken,
181 * shouldn't be called otherwise!
182 */
183static void __ll_do_awake(struct ll_struct *ll)
184{
185 struct sk_buff *skb = NULL;
186
187 while ((skb = skb_dequeue(&ll->tx_wait_q)))
188 skb_queue_tail(&ll->txq, skb);
189
190 ll->hcill_state = HCILL_AWAKE;
191}
192
193/*
194 * Called upon a wake-up-indication from the device
195 */
196static void ll_device_want_to_wakeup(struct hci_uart *hu)
197{
198 unsigned long flags;
199 struct ll_struct *ll = hu->priv;
200
201 BT_DBG("hu %p", hu);
202
203 /* lock hcill state */
204 spin_lock_irqsave(&ll->hcill_lock, flags);
205
206 switch (ll->hcill_state) {
Ohad Ben-Cohen5c548222008-01-10 22:24:43 -0800207 case HCILL_ASLEEP_TO_AWAKE:
208 /*
209 * This state means that both the host and the BRF chip
210 * have simultaneously sent a wake-up-indication packet.
211 * Traditionaly, in this case, receiving a wake-up-indication
212 * was enough and an additional wake-up-ack wasn't needed.
213 * This has changed with the BRF6350, which does require an
214 * explicit wake-up-ack. Other BRF versions, which do not
215 * require an explicit ack here, do accept it, thus it is
216 * perfectly safe to always send one.
217 */
218 BT_DBG("dual wake-up-indication");
219 /* deliberate fall-through - do not add break */
Ohad Ben-Cohen166d2f62007-10-20 13:42:36 +0200220 case HCILL_ASLEEP:
221 /* acknowledge device wake up */
222 if (send_hcill_cmd(HCILL_WAKE_UP_ACK, hu) < 0) {
223 BT_ERR("cannot acknowledge device wake up");
224 goto out;
225 }
226 break;
Ohad Ben-Cohen166d2f62007-10-20 13:42:36 +0200227 default:
Ohad Ben-Cohen5c548222008-01-10 22:24:43 -0800228 /* any other state is illegal */
Ohad Ben-Cohen166d2f62007-10-20 13:42:36 +0200229 BT_ERR("received HCILL_WAKE_UP_IND in state %ld", ll->hcill_state);
230 break;
231 }
232
233 /* send pending packets and change state to HCILL_AWAKE */
234 __ll_do_awake(ll);
235
236out:
237 spin_unlock_irqrestore(&ll->hcill_lock, flags);
238
239 /* actually send the packets */
240 hci_uart_tx_wakeup(hu);
241}
242
243/*
244 * Called upon a sleep-indication from the device
245 */
246static void ll_device_want_to_sleep(struct hci_uart *hu)
247{
248 unsigned long flags;
249 struct ll_struct *ll = hu->priv;
250
251 BT_DBG("hu %p", hu);
252
253 /* lock hcill state */
254 spin_lock_irqsave(&ll->hcill_lock, flags);
255
256 /* sanity check */
257 if (ll->hcill_state != HCILL_AWAKE)
258 BT_ERR("ERR: HCILL_GO_TO_SLEEP_IND in state %ld", ll->hcill_state);
259
260 /* acknowledge device sleep */
261 if (send_hcill_cmd(HCILL_GO_TO_SLEEP_ACK, hu) < 0) {
262 BT_ERR("cannot acknowledge device sleep");
263 goto out;
264 }
265
266 /* update state */
267 ll->hcill_state = HCILL_ASLEEP;
268
269out:
270 spin_unlock_irqrestore(&ll->hcill_lock, flags);
271
272 /* actually send the sleep ack packet */
273 hci_uart_tx_wakeup(hu);
274}
275
276/*
277 * Called upon wake-up-acknowledgement from the device
278 */
279static void ll_device_woke_up(struct hci_uart *hu)
280{
281 unsigned long flags;
282 struct ll_struct *ll = hu->priv;
283
284 BT_DBG("hu %p", hu);
285
286 /* lock hcill state */
287 spin_lock_irqsave(&ll->hcill_lock, flags);
288
289 /* sanity check */
290 if (ll->hcill_state != HCILL_ASLEEP_TO_AWAKE)
291 BT_ERR("received HCILL_WAKE_UP_ACK in state %ld", ll->hcill_state);
292
293 /* send pending packets and change state to HCILL_AWAKE */
294 __ll_do_awake(ll);
295
296 spin_unlock_irqrestore(&ll->hcill_lock, flags);
297
298 /* actually send the packets */
299 hci_uart_tx_wakeup(hu);
300}
301
302/* Enqueue frame for transmittion (padding, crc, etc) */
303/* may be called from two simultaneous tasklets */
304static int ll_enqueue(struct hci_uart *hu, struct sk_buff *skb)
305{
306 unsigned long flags = 0;
307 struct ll_struct *ll = hu->priv;
308
309 BT_DBG("hu %p skb %p", hu, skb);
310
311 /* Prepend skb with frame type */
312 memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
313
314 /* lock hcill state */
315 spin_lock_irqsave(&ll->hcill_lock, flags);
316
317 /* act according to current state */
318 switch (ll->hcill_state) {
319 case HCILL_AWAKE:
320 BT_DBG("device awake, sending normally");
321 skb_queue_tail(&ll->txq, skb);
322 break;
323 case HCILL_ASLEEP:
324 BT_DBG("device asleep, waking up and queueing packet");
325 /* save packet for later */
326 skb_queue_tail(&ll->tx_wait_q, skb);
327 /* awake device */
328 if (send_hcill_cmd(HCILL_WAKE_UP_IND, hu) < 0) {
329 BT_ERR("cannot wake up device");
330 break;
331 }
332 ll->hcill_state = HCILL_ASLEEP_TO_AWAKE;
333 break;
334 case HCILL_ASLEEP_TO_AWAKE:
335 BT_DBG("device waking up, queueing packet");
336 /* transient state; just keep packet for later */
337 skb_queue_tail(&ll->tx_wait_q, skb);
338 break;
339 default:
340 BT_ERR("illegal hcill state: %ld (losing packet)", ll->hcill_state);
341 kfree_skb(skb);
342 break;
343 }
344
345 spin_unlock_irqrestore(&ll->hcill_lock, flags);
346
347 return 0;
348}
349
350static inline int ll_check_data_len(struct ll_struct *ll, int len)
351{
352 register int room = skb_tailroom(ll->rx_skb);
353
354 BT_DBG("len %d room %d", len, room);
355
356 if (!len) {
357 hci_recv_frame(ll->rx_skb);
358 } else if (len > room) {
359 BT_ERR("Data length is too large");
360 kfree_skb(ll->rx_skb);
361 } else {
362 ll->rx_state = HCILL_W4_DATA;
363 ll->rx_count = len;
364 return len;
365 }
366
367 ll->rx_state = HCILL_W4_PACKET_TYPE;
368 ll->rx_skb = NULL;
369 ll->rx_count = 0;
370
371 return 0;
372}
373
374/* Recv data */
375static int ll_recv(struct hci_uart *hu, void *data, int count)
376{
377 struct ll_struct *ll = hu->priv;
378 register char *ptr;
379 struct hci_event_hdr *eh;
380 struct hci_acl_hdr *ah;
381 struct hci_sco_hdr *sh;
382 register int len, type, dlen;
383
384 BT_DBG("hu %p count %d rx_state %ld rx_count %ld", hu, count, ll->rx_state, ll->rx_count);
385
386 ptr = data;
387 while (count) {
388 if (ll->rx_count) {
389 len = min_t(unsigned int, ll->rx_count, count);
390 memcpy(skb_put(ll->rx_skb, len), ptr, len);
391 ll->rx_count -= len; count -= len; ptr += len;
392
393 if (ll->rx_count)
394 continue;
395
396 switch (ll->rx_state) {
397 case HCILL_W4_DATA:
398 BT_DBG("Complete data");
399 hci_recv_frame(ll->rx_skb);
400
401 ll->rx_state = HCILL_W4_PACKET_TYPE;
402 ll->rx_skb = NULL;
403 continue;
404
405 case HCILL_W4_EVENT_HDR:
406 eh = (struct hci_event_hdr *) ll->rx_skb->data;
407
408 BT_DBG("Event header: evt 0x%2.2x plen %d", eh->evt, eh->plen);
409
410 ll_check_data_len(ll, eh->plen);
411 continue;
412
413 case HCILL_W4_ACL_HDR:
414 ah = (struct hci_acl_hdr *) ll->rx_skb->data;
415 dlen = __le16_to_cpu(ah->dlen);
416
417 BT_DBG("ACL header: dlen %d", dlen);
418
419 ll_check_data_len(ll, dlen);
420 continue;
421
422 case HCILL_W4_SCO_HDR:
423 sh = (struct hci_sco_hdr *) ll->rx_skb->data;
424
425 BT_DBG("SCO header: dlen %d", sh->dlen);
426
427 ll_check_data_len(ll, sh->dlen);
428 continue;
429 }
430 }
431
432 /* HCILL_W4_PACKET_TYPE */
433 switch (*ptr) {
434 case HCI_EVENT_PKT:
435 BT_DBG("Event packet");
436 ll->rx_state = HCILL_W4_EVENT_HDR;
437 ll->rx_count = HCI_EVENT_HDR_SIZE;
438 type = HCI_EVENT_PKT;
439 break;
440
441 case HCI_ACLDATA_PKT:
442 BT_DBG("ACL packet");
443 ll->rx_state = HCILL_W4_ACL_HDR;
444 ll->rx_count = HCI_ACL_HDR_SIZE;
445 type = HCI_ACLDATA_PKT;
446 break;
447
448 case HCI_SCODATA_PKT:
449 BT_DBG("SCO packet");
450 ll->rx_state = HCILL_W4_SCO_HDR;
451 ll->rx_count = HCI_SCO_HDR_SIZE;
452 type = HCI_SCODATA_PKT;
453 break;
454
455 /* HCILL signals */
456 case HCILL_GO_TO_SLEEP_IND:
457 BT_DBG("HCILL_GO_TO_SLEEP_IND packet");
458 ll_device_want_to_sleep(hu);
459 ptr++; count--;
460 continue;
461
462 case HCILL_GO_TO_SLEEP_ACK:
463 /* shouldn't happen */
464 BT_ERR("received HCILL_GO_TO_SLEEP_ACK (in state %ld)", ll->hcill_state);
465 ptr++; count--;
466 continue;
467
468 case HCILL_WAKE_UP_IND:
469 BT_DBG("HCILL_WAKE_UP_IND packet");
470 ll_device_want_to_wakeup(hu);
471 ptr++; count--;
472 continue;
473
474 case HCILL_WAKE_UP_ACK:
475 BT_DBG("HCILL_WAKE_UP_ACK packet");
476 ll_device_woke_up(hu);
477 ptr++; count--;
478 continue;
479
480 default:
481 BT_ERR("Unknown HCI packet type %2.2x", (__u8)*ptr);
482 hu->hdev->stat.err_rx++;
483 ptr++; count--;
484 continue;
485 };
486
487 ptr++; count--;
488
489 /* Allocate packet */
490 ll->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);
491 if (!ll->rx_skb) {
492 BT_ERR("Can't allocate mem for new packet");
493 ll->rx_state = HCILL_W4_PACKET_TYPE;
494 ll->rx_count = 0;
495 return 0;
496 }
497
498 ll->rx_skb->dev = (void *) hu->hdev;
499 bt_cb(ll->rx_skb)->pkt_type = type;
500 }
501
502 return count;
503}
504
505static struct sk_buff *ll_dequeue(struct hci_uart *hu)
506{
507 struct ll_struct *ll = hu->priv;
508 return skb_dequeue(&ll->txq);
509}
510
511static struct hci_uart_proto llp = {
512 .id = HCI_UART_LL,
513 .open = ll_open,
514 .close = ll_close,
515 .recv = ll_recv,
516 .enqueue = ll_enqueue,
517 .dequeue = ll_dequeue,
518 .flush = ll_flush,
519};
520
521int ll_init(void)
522{
523 int err = hci_uart_register_proto(&llp);
524
525 if (!err)
526 BT_INFO("HCILL protocol initialized");
527 else
528 BT_ERR("HCILL protocol registration failed");
529
530 return err;
531}
532
533int ll_deinit(void)
534{
535 return hci_uart_unregister_proto(&llp);
536}