Root/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 */
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} __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_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 */
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    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 */
182static 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 */
195static 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
235out:
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 */
245static 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
268out:
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 */
278static 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 */
303static 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
349static inline int ll_check_data_len(struct ll_struct *ll, int len)
350{
351    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 */
374static int ll_recv(struct hci_uart *hu, void *data, int count)
375{
376    struct ll_struct *ll = hu->priv;
377    char *ptr;
378    struct hci_event_hdr *eh;
379    struct hci_acl_hdr *ah;
380    struct hci_sco_hdr *sh;
381    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
504static 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
510static 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
520int __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
532int __exit ll_deinit(void)
533{
534    return hci_uart_unregister_proto(&llp);
535}
536

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