Bluetooth: Fix return value when bt_skb_alloc fails
[linux-2.6.git] / drivers / bluetooth / hci_ll.c
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 } __attribute__((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  */
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 */
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_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 */
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 */
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  */
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  */
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                  * Traditionaly, 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  */
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  */
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 */
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
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 */
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 = (struct hci_event_hdr *) ll->rx_skb->data;
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 = (struct hci_acl_hdr *) ll->rx_skb->data;
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 = (struct hci_sco_hdr *) ll->rx_skb->data;
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
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
520 int 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
532 int ll_deinit(void)
533 {
534         return hci_uart_unregister_proto(&llp);
535 }