3 * Bluetooth HCI Three-wire UART driver
5 * Copyright (C) 2012 Intel Corporation
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include <linux/kernel.h>
25 #include <linux/errno.h>
26 #include <linux/skbuff.h>
28 #include <net/bluetooth/bluetooth.h>
29 #include <net/bluetooth/hci_core.h>
33 #define HCI_3WIRE_ACK_PKT 0
34 #define HCI_3WIRE_LINK_PKT 15
36 /* Sliding window size */
37 #define H5_TX_WIN_MAX 4
39 #define H5_ACK_TIMEOUT msecs_to_jiffies(250)
40 #define H5_SYNC_TIMEOUT msecs_to_jiffies(100)
43 * Maximum Three-wire packet:
44 * 4 byte header + max value for 12-bit length + 2 bytes for CRC
46 #define H5_MAX_LEN (4 + 0xfff + 2)
48 /* Convenience macros for reading Three-wire header values */
49 #define H5_HDR_SEQ(hdr) ((hdr)[0] & 0x07)
50 #define H5_HDR_ACK(hdr) (((hdr)[0] >> 3) & 0x07)
51 #define H5_HDR_CRC(hdr) (((hdr)[0] >> 6) & 0x01)
52 #define H5_HDR_RELIABLE(hdr) (((hdr)[0] >> 7) & 0x01)
53 #define H5_HDR_PKT_TYPE(hdr) ((hdr)[1] & 0x0f)
54 #define H5_HDR_LEN(hdr) ((((hdr)[1] >> 4) & 0xff) + ((hdr)[2] << 4))
56 #define SLIP_DELIMITER 0xc0
58 #define SLIP_ESC_DELIM 0xdc
59 #define SLIP_ESC_ESC 0xdd
63 H5_RX_ESC, /* SLIP escape mode */
64 H5_TX_ACK_REQ, /* Pending ack to send */
68 struct sk_buff_head unack; /* Unack'ed packets queue */
69 struct sk_buff_head rel; /* Reliable packets queue */
70 struct sk_buff_head unrel; /* Unreliable packets queue */
74 struct sk_buff *rx_skb; /* Receive buffer */
75 size_t rx_pending; /* Expecting more bytes */
76 u8 rx_ack; /* Last ack number received */
78 int (*rx_func) (struct hci_uart *hu, u8 c);
80 struct timer_list timer; /* Retransmission timer */
82 u8 tx_seq; /* Next seq number to send */
83 u8 tx_ack; /* Next ack number to send */
84 u8 tx_win; /* Sliding window size */
99 static void h5_reset_rx(struct h5 *h5);
101 static void h5_link_control(struct hci_uart *hu, const void *data, size_t len)
103 struct h5 *h5 = hu->priv;
104 struct sk_buff *nskb;
106 nskb = alloc_skb(3, GFP_ATOMIC);
110 bt_cb(nskb)->pkt_type = HCI_3WIRE_LINK_PKT;
112 memcpy(skb_put(nskb, len), data, len);
114 skb_queue_tail(&h5->unrel, nskb);
117 static u8 h5_cfg_field(struct h5 *h5)
121 /* Sliding window size (first 3 bits) */
122 field |= (h5->tx_win & 7);
127 static void h5_timed_event(unsigned long arg)
129 const unsigned char sync_req[] = { 0x01, 0x7e };
130 unsigned char conf_req[] = { 0x03, 0xfc, 0x01 };
131 struct hci_uart *hu = (struct hci_uart *) arg;
132 struct h5 *h5 = hu->priv;
136 BT_DBG("%s", hu->hdev->name);
138 if (h5->state == H5_UNINITIALIZED)
139 h5_link_control(hu, sync_req, sizeof(sync_req));
141 if (h5->state == H5_INITIALIZED) {
142 conf_req[2] = h5_cfg_field(h5);
143 h5_link_control(hu, conf_req, sizeof(conf_req));
146 if (h5->state != H5_ACTIVE) {
147 mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
151 if (h5->sleep != H5_AWAKE) {
152 h5->sleep = H5_SLEEPING;
156 BT_DBG("hu %p retransmitting %u pkts", hu, h5->unack.qlen);
158 spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
160 while ((skb = __skb_dequeue_tail(&h5->unack)) != NULL) {
161 h5->tx_seq = (h5->tx_seq - 1) & 0x07;
162 skb_queue_head(&h5->rel, skb);
165 spin_unlock_irqrestore(&h5->unack.lock, flags);
168 hci_uart_tx_wakeup(hu);
171 static void h5_peer_reset(struct hci_uart *hu)
173 struct h5 *h5 = hu->priv;
175 const unsigned char hard_err[] = { 0x10, 0x01, 0x00 };
177 BT_ERR("Peer device has reset");
179 h5->state = H5_UNINITIALIZED;
181 del_timer(&h5->timer);
183 skb_queue_purge(&h5->rel);
184 skb_queue_purge(&h5->unrel);
185 skb_queue_purge(&h5->unack);
190 skb = bt_skb_alloc(3, GFP_ATOMIC);
194 bt_cb(skb)->pkt_type = HCI_EVENT_PKT;
195 memcpy(skb_put(skb, 3), hard_err, 3);
197 /* Send Hardware Error to upper stack */
198 hci_recv_frame(hu->hdev, skb);
201 static int h5_open(struct hci_uart *hu)
204 const unsigned char sync[] = { 0x01, 0x7e };
208 h5 = kzalloc(sizeof(*h5), GFP_KERNEL);
214 skb_queue_head_init(&h5->unack);
215 skb_queue_head_init(&h5->rel);
216 skb_queue_head_init(&h5->unrel);
220 init_timer(&h5->timer);
221 h5->timer.function = h5_timed_event;
222 h5->timer.data = (unsigned long) hu;
224 h5->tx_win = H5_TX_WIN_MAX;
226 set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags);
228 /* Send initial sync request */
229 h5_link_control(hu, sync, sizeof(sync));
230 mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
235 static int h5_close(struct hci_uart *hu)
237 struct h5 *h5 = hu->priv;
239 del_timer_sync(&h5->timer);
241 skb_queue_purge(&h5->unack);
242 skb_queue_purge(&h5->rel);
243 skb_queue_purge(&h5->unrel);
250 static void h5_pkt_cull(struct h5 *h5)
252 struct sk_buff *skb, *tmp;
257 spin_lock_irqsave(&h5->unack.lock, flags);
259 to_remove = skb_queue_len(&h5->unack);
265 while (to_remove > 0) {
266 if (h5->rx_ack == seq)
270 seq = (seq - 1) & 0x07;
273 if (seq != h5->rx_ack)
274 BT_ERR("Controller acked invalid packet");
277 skb_queue_walk_safe(&h5->unack, skb, tmp) {
278 if (i++ >= to_remove)
281 __skb_unlink(skb, &h5->unack);
285 if (skb_queue_empty(&h5->unack))
286 del_timer(&h5->timer);
289 spin_unlock_irqrestore(&h5->unack.lock, flags);
292 static void h5_handle_internal_rx(struct hci_uart *hu)
294 struct h5 *h5 = hu->priv;
295 const unsigned char sync_req[] = { 0x01, 0x7e };
296 const unsigned char sync_rsp[] = { 0x02, 0x7d };
297 unsigned char conf_req[] = { 0x03, 0xfc, 0x01 };
298 const unsigned char conf_rsp[] = { 0x04, 0x7b };
299 const unsigned char wakeup_req[] = { 0x05, 0xfa };
300 const unsigned char woken_req[] = { 0x06, 0xf9 };
301 const unsigned char sleep_req[] = { 0x07, 0x78 };
302 const unsigned char *hdr = h5->rx_skb->data;
303 const unsigned char *data = &h5->rx_skb->data[4];
305 BT_DBG("%s", hu->hdev->name);
307 if (H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT)
310 if (H5_HDR_LEN(hdr) < 2)
313 conf_req[2] = h5_cfg_field(h5);
315 if (memcmp(data, sync_req, 2) == 0) {
316 if (h5->state == H5_ACTIVE)
318 h5_link_control(hu, sync_rsp, 2);
319 } else if (memcmp(data, sync_rsp, 2) == 0) {
320 if (h5->state == H5_ACTIVE)
322 h5->state = H5_INITIALIZED;
323 h5_link_control(hu, conf_req, 3);
324 } else if (memcmp(data, conf_req, 2) == 0) {
325 h5_link_control(hu, conf_rsp, 2);
326 h5_link_control(hu, conf_req, 3);
327 } else if (memcmp(data, conf_rsp, 2) == 0) {
328 if (H5_HDR_LEN(hdr) > 2)
329 h5->tx_win = (data[2] & 7);
330 BT_DBG("Three-wire init complete. tx_win %u", h5->tx_win);
331 h5->state = H5_ACTIVE;
332 hci_uart_init_ready(hu);
334 } else if (memcmp(data, sleep_req, 2) == 0) {
335 BT_DBG("Peer went to sleep");
336 h5->sleep = H5_SLEEPING;
338 } else if (memcmp(data, woken_req, 2) == 0) {
339 BT_DBG("Peer woke up");
340 h5->sleep = H5_AWAKE;
341 } else if (memcmp(data, wakeup_req, 2) == 0) {
342 BT_DBG("Peer requested wakeup");
343 h5_link_control(hu, woken_req, 2);
344 h5->sleep = H5_AWAKE;
346 BT_DBG("Link Control: 0x%02hhx 0x%02hhx", data[0], data[1]);
350 hci_uart_tx_wakeup(hu);
353 static void h5_complete_rx_pkt(struct hci_uart *hu)
355 struct h5 *h5 = hu->priv;
356 const unsigned char *hdr = h5->rx_skb->data;
358 if (H5_HDR_RELIABLE(hdr)) {
359 h5->tx_ack = (h5->tx_ack + 1) % 8;
360 set_bit(H5_TX_ACK_REQ, &h5->flags);
361 hci_uart_tx_wakeup(hu);
364 h5->rx_ack = H5_HDR_ACK(hdr);
368 switch (H5_HDR_PKT_TYPE(hdr)) {
370 case HCI_ACLDATA_PKT:
371 case HCI_SCODATA_PKT:
372 bt_cb(h5->rx_skb)->pkt_type = H5_HDR_PKT_TYPE(hdr);
374 /* Remove Three-wire header */
375 skb_pull(h5->rx_skb, 4);
377 hci_recv_frame(hu->hdev, h5->rx_skb);
383 h5_handle_internal_rx(hu);
390 static int h5_rx_crc(struct hci_uart *hu, unsigned char c)
392 h5_complete_rx_pkt(hu);
397 static int h5_rx_payload(struct hci_uart *hu, unsigned char c)
399 struct h5 *h5 = hu->priv;
400 const unsigned char *hdr = h5->rx_skb->data;
402 if (H5_HDR_CRC(hdr)) {
403 h5->rx_func = h5_rx_crc;
406 h5_complete_rx_pkt(hu);
412 static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c)
414 struct h5 *h5 = hu->priv;
415 const unsigned char *hdr = h5->rx_skb->data;
417 BT_DBG("%s rx: seq %u ack %u crc %u rel %u type %u len %u",
418 hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
419 H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
422 if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) {
423 BT_ERR("Invalid header checksum");
428 if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_ack) {
429 BT_ERR("Out-of-order packet arrived (%u != %u)",
430 H5_HDR_SEQ(hdr), h5->tx_ack);
435 if (h5->state != H5_ACTIVE &&
436 H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT) {
437 BT_ERR("Non-link packet received in non-active state");
442 h5->rx_func = h5_rx_payload;
443 h5->rx_pending = H5_HDR_LEN(hdr);
448 static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c)
450 struct h5 *h5 = hu->priv;
452 if (c == SLIP_DELIMITER)
455 h5->rx_func = h5_rx_3wire_hdr;
458 h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC);
460 BT_ERR("Can't allocate mem for new packet");
465 h5->rx_skb->dev = (void *) hu->hdev;
470 static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c)
472 struct h5 *h5 = hu->priv;
474 if (c == SLIP_DELIMITER)
475 h5->rx_func = h5_rx_pkt_start;
480 static void h5_unslip_one_byte(struct h5 *h5, unsigned char c)
482 const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC;
485 if (!test_bit(H5_RX_ESC, &h5->flags) && c == SLIP_ESC) {
486 set_bit(H5_RX_ESC, &h5->flags);
490 if (test_and_clear_bit(H5_RX_ESC, &h5->flags)) {
499 BT_ERR("Invalid esc byte 0x%02hhx", c);
505 memcpy(skb_put(h5->rx_skb, 1), byte, 1);
508 BT_DBG("unsliped 0x%02hhx, rx_pending %zu", *byte, h5->rx_pending);
511 static void h5_reset_rx(struct h5 *h5)
514 kfree_skb(h5->rx_skb);
518 h5->rx_func = h5_rx_delimiter;
520 clear_bit(H5_RX_ESC, &h5->flags);
523 static int h5_recv(struct hci_uart *hu, void *data, int count)
525 struct h5 *h5 = hu->priv;
526 unsigned char *ptr = data;
528 BT_DBG("%s pending %zu count %d", hu->hdev->name, h5->rx_pending,
534 if (h5->rx_pending > 0) {
535 if (*ptr == SLIP_DELIMITER) {
536 BT_ERR("Too short H5 packet");
541 h5_unslip_one_byte(h5, *ptr);
547 processed = h5->rx_func(hu, *ptr);
558 static int h5_enqueue(struct hci_uart *hu, struct sk_buff *skb)
560 struct h5 *h5 = hu->priv;
562 if (skb->len > 0xfff) {
563 BT_ERR("Packet too long (%u bytes)", skb->len);
568 if (h5->state != H5_ACTIVE) {
569 BT_ERR("Ignoring HCI data in non-active state");
574 switch (bt_cb(skb)->pkt_type) {
575 case HCI_ACLDATA_PKT:
576 case HCI_COMMAND_PKT:
577 skb_queue_tail(&h5->rel, skb);
580 case HCI_SCODATA_PKT:
581 skb_queue_tail(&h5->unrel, skb);
585 BT_ERR("Unknown packet type %u", bt_cb(skb)->pkt_type);
593 static void h5_slip_delim(struct sk_buff *skb)
595 const char delim = SLIP_DELIMITER;
597 memcpy(skb_put(skb, 1), &delim, 1);
600 static void h5_slip_one_byte(struct sk_buff *skb, u8 c)
602 const char esc_delim[2] = { SLIP_ESC, SLIP_ESC_DELIM };
603 const char esc_esc[2] = { SLIP_ESC, SLIP_ESC_ESC };
607 memcpy(skb_put(skb, 2), &esc_delim, 2);
610 memcpy(skb_put(skb, 2), &esc_esc, 2);
613 memcpy(skb_put(skb, 1), &c, 1);
617 static bool valid_packet_type(u8 type)
620 case HCI_ACLDATA_PKT:
621 case HCI_COMMAND_PKT:
622 case HCI_SCODATA_PKT:
623 case HCI_3WIRE_LINK_PKT:
624 case HCI_3WIRE_ACK_PKT:
631 static struct sk_buff *h5_prepare_pkt(struct hci_uart *hu, u8 pkt_type,
632 const u8 *data, size_t len)
634 struct h5 *h5 = hu->priv;
635 struct sk_buff *nskb;
639 if (!valid_packet_type(pkt_type)) {
640 BT_ERR("Unknown packet type %u", pkt_type);
645 * Max len of packet: (original len + 4 (H5 hdr) + 2 (crc)) * 2
646 * (because bytes 0xc0 and 0xdb are escaped, worst case is when
647 * the packet is all made of 0xc0 and 0xdb) + 2 (0xc0
648 * delimiters at start and end).
650 nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
654 bt_cb(nskb)->pkt_type = pkt_type;
658 hdr[0] = h5->tx_ack << 3;
659 clear_bit(H5_TX_ACK_REQ, &h5->flags);
661 /* Reliable packet? */
662 if (pkt_type == HCI_ACLDATA_PKT || pkt_type == HCI_COMMAND_PKT) {
664 hdr[0] |= h5->tx_seq;
665 h5->tx_seq = (h5->tx_seq + 1) % 8;
668 hdr[1] = pkt_type | ((len & 0x0f) << 4);
670 hdr[3] = ~((hdr[0] + hdr[1] + hdr[2]) & 0xff);
672 BT_DBG("%s tx: seq %u ack %u crc %u rel %u type %u len %u",
673 hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
674 H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
677 for (i = 0; i < 4; i++)
678 h5_slip_one_byte(nskb, hdr[i]);
680 for (i = 0; i < len; i++)
681 h5_slip_one_byte(nskb, data[i]);
688 static struct sk_buff *h5_dequeue(struct hci_uart *hu)
690 struct h5 *h5 = hu->priv;
692 struct sk_buff *skb, *nskb;
694 if (h5->sleep != H5_AWAKE) {
695 const unsigned char wakeup_req[] = { 0x05, 0xfa };
697 if (h5->sleep == H5_WAKING_UP)
700 h5->sleep = H5_WAKING_UP;
701 BT_DBG("Sending wakeup request");
703 mod_timer(&h5->timer, jiffies + HZ / 100);
704 return h5_prepare_pkt(hu, HCI_3WIRE_LINK_PKT, wakeup_req, 2);
707 skb = skb_dequeue(&h5->unrel);
709 nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
710 skb->data, skb->len);
716 skb_queue_head(&h5->unrel, skb);
717 BT_ERR("Could not dequeue pkt because alloc_skb failed");
720 spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
722 if (h5->unack.qlen >= h5->tx_win)
725 skb = skb_dequeue(&h5->rel);
727 nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
728 skb->data, skb->len);
730 __skb_queue_tail(&h5->unack, skb);
731 mod_timer(&h5->timer, jiffies + H5_ACK_TIMEOUT);
732 spin_unlock_irqrestore(&h5->unack.lock, flags);
736 skb_queue_head(&h5->rel, skb);
737 BT_ERR("Could not dequeue pkt because alloc_skb failed");
741 spin_unlock_irqrestore(&h5->unack.lock, flags);
743 if (test_bit(H5_TX_ACK_REQ, &h5->flags))
744 return h5_prepare_pkt(hu, HCI_3WIRE_ACK_PKT, NULL, 0);
749 static int h5_flush(struct hci_uart *hu)
755 static struct hci_uart_proto h5p = {
756 .id = HCI_UART_3WIRE,
760 .enqueue = h5_enqueue,
761 .dequeue = h5_dequeue,
765 int __init h5_init(void)
767 int err = hci_uart_register_proto(&h5p);
770 BT_INFO("HCI Three-wire UART (H5) protocol initialized");
772 BT_ERR("HCI Three-wire UART (H5) protocol init failed");
777 int __exit h5_deinit(void)
779 return hci_uart_unregister_proto(&h5p);