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 int h5_open(struct hci_uart
*hu
)
174 const unsigned char sync
[] = { 0x01, 0x7e };
178 h5
= kzalloc(sizeof(*h5
), GFP_KERNEL
);
184 skb_queue_head_init(&h5
->unack
);
185 skb_queue_head_init(&h5
->rel
);
186 skb_queue_head_init(&h5
->unrel
);
190 init_timer(&h5
->timer
);
191 h5
->timer
.function
= h5_timed_event
;
192 h5
->timer
.data
= (unsigned long) hu
;
194 h5
->tx_win
= H5_TX_WIN_MAX
;
196 set_bit(HCI_UART_INIT_PENDING
, &hu
->hdev_flags
);
198 /* Send initial sync request */
199 h5_link_control(hu
, sync
, sizeof(sync
));
200 mod_timer(&h5
->timer
, jiffies
+ H5_SYNC_TIMEOUT
);
205 static int h5_close(struct hci_uart
*hu
)
207 struct h5
*h5
= hu
->priv
;
209 skb_queue_purge(&h5
->unack
);
210 skb_queue_purge(&h5
->rel
);
211 skb_queue_purge(&h5
->unrel
);
213 del_timer(&h5
->timer
);
220 static void h5_pkt_cull(struct h5
*h5
)
222 struct sk_buff
*skb
, *tmp
;
227 spin_lock_irqsave(&h5
->unack
.lock
, flags
);
229 to_remove
= skb_queue_len(&h5
->unack
);
235 while (to_remove
> 0) {
236 if (h5
->rx_ack
== seq
)
243 if (seq
!= h5
->rx_ack
)
244 BT_ERR("Controller acked invalid packet");
247 skb_queue_walk_safe(&h5
->unack
, skb
, tmp
) {
248 if (i
++ >= to_remove
)
251 __skb_unlink(skb
, &h5
->unack
);
255 if (skb_queue_empty(&h5
->unack
))
256 del_timer(&h5
->timer
);
259 spin_unlock_irqrestore(&h5
->unack
.lock
, flags
);
262 static void h5_handle_internal_rx(struct hci_uart
*hu
)
264 struct h5
*h5
= hu
->priv
;
265 const unsigned char sync_req
[] = { 0x01, 0x7e };
266 const unsigned char sync_rsp
[] = { 0x02, 0x7d };
267 unsigned char conf_req
[] = { 0x03, 0xfc, 0x01 };
268 const unsigned char conf_rsp
[] = { 0x04, 0x7b };
269 const unsigned char wakeup_req
[] = { 0x05, 0xfa };
270 const unsigned char woken_req
[] = { 0x06, 0xf9 };
271 const unsigned char sleep_req
[] = { 0x07, 0x78 };
272 const unsigned char *hdr
= h5
->rx_skb
->data
;
273 const unsigned char *data
= &h5
->rx_skb
->data
[4];
275 BT_DBG("%s", hu
->hdev
->name
);
277 if (H5_HDR_PKT_TYPE(hdr
) != HCI_3WIRE_LINK_PKT
)
280 if (H5_HDR_LEN(hdr
) < 2)
283 conf_req
[2] = h5_cfg_field(h5
);
285 if (memcmp(data
, sync_req
, 2) == 0) {
286 h5_link_control(hu
, sync_rsp
, 2);
287 } else if (memcmp(data
, sync_rsp
, 2) == 0) {
288 h5
->state
= H5_INITIALIZED
;
289 h5_link_control(hu
, conf_req
, 3);
290 } else if (memcmp(data
, conf_req
, 2) == 0) {
291 h5_link_control(hu
, conf_rsp
, 2);
292 h5_link_control(hu
, conf_req
, 3);
293 } else if (memcmp(data
, conf_rsp
, 2) == 0) {
294 if (H5_HDR_LEN(hdr
) > 2)
295 h5
->tx_win
= (data
[2] & 7);
296 BT_DBG("Three-wire init complete. tx_win %u", h5
->tx_win
);
297 h5
->state
= H5_ACTIVE
;
298 hci_uart_init_ready(hu
);
300 } else if (memcmp(data
, sleep_req
, 2) == 0) {
301 BT_DBG("Peer went to sleep");
302 h5
->sleep
= H5_SLEEPING
;
304 } else if (memcmp(data
, woken_req
, 2) == 0) {
305 BT_DBG("Peer woke up");
306 h5
->sleep
= H5_AWAKE
;
307 } else if (memcmp(data
, wakeup_req
, 2) == 0) {
308 BT_DBG("Peer requested wakeup");
309 h5_link_control(hu
, woken_req
, 2);
310 h5
->sleep
= H5_AWAKE
;
312 BT_DBG("Link Control: 0x%02hhx 0x%02hhx", data
[0], data
[1]);
316 hci_uart_tx_wakeup(hu
);
319 static void h5_complete_rx_pkt(struct hci_uart
*hu
)
321 struct h5
*h5
= hu
->priv
;
322 const unsigned char *hdr
= h5
->rx_skb
->data
;
324 if (H5_HDR_RELIABLE(hdr
)) {
325 h5
->tx_ack
= (h5
->tx_ack
+ 1) % 8;
326 set_bit(H5_TX_ACK_REQ
, &h5
->flags
);
327 hci_uart_tx_wakeup(hu
);
330 h5
->rx_ack
= H5_HDR_ACK(hdr
);
334 switch (H5_HDR_PKT_TYPE(hdr
)) {
336 case HCI_ACLDATA_PKT
:
337 case HCI_SCODATA_PKT
:
338 bt_cb(h5
->rx_skb
)->pkt_type
= H5_HDR_PKT_TYPE(hdr
);
340 /* Remove Three-wire header */
341 skb_pull(h5
->rx_skb
, 4);
343 hci_recv_frame(h5
->rx_skb
);
349 h5_handle_internal_rx(hu
);
356 static int h5_rx_crc(struct hci_uart
*hu
, unsigned char c
)
358 struct h5
*h5
= hu
->priv
;
360 h5_complete_rx_pkt(hu
);
366 static int h5_rx_payload(struct hci_uart
*hu
, unsigned char c
)
368 struct h5
*h5
= hu
->priv
;
369 const unsigned char *hdr
= h5
->rx_skb
->data
;
371 if (H5_HDR_CRC(hdr
)) {
372 h5
->rx_func
= h5_rx_crc
;
375 h5_complete_rx_pkt(hu
);
382 static int h5_rx_3wire_hdr(struct hci_uart
*hu
, unsigned char c
)
384 struct h5
*h5
= hu
->priv
;
385 const unsigned char *hdr
= h5
->rx_skb
->data
;
387 BT_DBG("%s rx: seq %u ack %u crc %u rel %u type %u len %u",
388 hu
->hdev
->name
, H5_HDR_SEQ(hdr
), H5_HDR_ACK(hdr
),
389 H5_HDR_CRC(hdr
), H5_HDR_RELIABLE(hdr
), H5_HDR_PKT_TYPE(hdr
),
392 if (((hdr
[0] + hdr
[1] + hdr
[2] + hdr
[3]) & 0xff) != 0xff) {
393 BT_ERR("Invalid header checksum");
398 if (H5_HDR_RELIABLE(hdr
) && H5_HDR_SEQ(hdr
) != h5
->tx_ack
) {
399 BT_ERR("Out-of-order packet arrived (%u != %u)",
400 H5_HDR_SEQ(hdr
), h5
->tx_ack
);
405 if (h5
->state
!= H5_ACTIVE
&&
406 H5_HDR_PKT_TYPE(hdr
) != HCI_3WIRE_LINK_PKT
) {
407 BT_ERR("Non-link packet received in non-active state");
411 h5
->rx_func
= h5_rx_payload
;
412 h5
->rx_pending
= H5_HDR_LEN(hdr
);
417 static int h5_rx_pkt_start(struct hci_uart
*hu
, unsigned char c
)
419 struct h5
*h5
= hu
->priv
;
421 if (c
== SLIP_DELIMITER
)
424 h5
->rx_func
= h5_rx_3wire_hdr
;
427 h5
->rx_skb
= bt_skb_alloc(H5_MAX_LEN
, GFP_ATOMIC
);
429 BT_ERR("Can't allocate mem for new packet");
434 h5
->rx_skb
->dev
= (void *) hu
->hdev
;
439 static int h5_rx_delimiter(struct hci_uart
*hu
, unsigned char c
)
441 struct h5
*h5
= hu
->priv
;
443 if (c
== SLIP_DELIMITER
)
444 h5
->rx_func
= h5_rx_pkt_start
;
449 static void h5_unslip_one_byte(struct h5
*h5
, unsigned char c
)
451 const u8 delim
= SLIP_DELIMITER
, esc
= SLIP_ESC
;
454 if (!test_bit(H5_RX_ESC
, &h5
->flags
) && c
== SLIP_ESC
) {
455 set_bit(H5_RX_ESC
, &h5
->flags
);
459 if (test_and_clear_bit(H5_RX_ESC
, &h5
->flags
)) {
468 BT_ERR("Invalid esc byte 0x%02hhx", c
);
474 memcpy(skb_put(h5
->rx_skb
, 1), byte
, 1);
477 BT_DBG("unsliped 0x%02hhx, rx_pending %zu", *byte
, h5
->rx_pending
);
480 static void h5_reset_rx(struct h5
*h5
)
483 kfree_skb(h5
->rx_skb
);
487 h5
->rx_func
= h5_rx_delimiter
;
489 clear_bit(H5_RX_ESC
, &h5
->flags
);
492 static int h5_recv(struct hci_uart
*hu
, void *data
, int count
)
494 struct h5
*h5
= hu
->priv
;
495 unsigned char *ptr
= data
;
497 BT_DBG("%s pending %zu count %d", hu
->hdev
->name
, h5
->rx_pending
,
503 if (h5
->rx_pending
> 0) {
504 if (*ptr
== SLIP_DELIMITER
) {
505 BT_ERR("Too short H5 packet");
510 h5_unslip_one_byte(h5
, *ptr
);
516 processed
= h5
->rx_func(hu
, *ptr
);
527 static int h5_enqueue(struct hci_uart
*hu
, struct sk_buff
*skb
)
529 struct h5
*h5
= hu
->priv
;
531 if (skb
->len
> 0xfff) {
532 BT_ERR("Packet too long (%u bytes)", skb
->len
);
537 if (h5
->state
!= H5_ACTIVE
) {
538 BT_ERR("Ignoring HCI data in non-active state");
543 switch (bt_cb(skb
)->pkt_type
) {
544 case HCI_ACLDATA_PKT
:
545 case HCI_COMMAND_PKT
:
546 skb_queue_tail(&h5
->rel
, skb
);
549 case HCI_SCODATA_PKT
:
550 skb_queue_tail(&h5
->unrel
, skb
);
554 BT_ERR("Unknown packet type %u", bt_cb(skb
)->pkt_type
);
562 static void h5_slip_delim(struct sk_buff
*skb
)
564 const char delim
= SLIP_DELIMITER
;
566 memcpy(skb_put(skb
, 1), &delim
, 1);
569 static void h5_slip_one_byte(struct sk_buff
*skb
, u8 c
)
571 const char esc_delim
[2] = { SLIP_ESC
, SLIP_ESC_DELIM
};
572 const char esc_esc
[2] = { SLIP_ESC
, SLIP_ESC_ESC
};
576 memcpy(skb_put(skb
, 2), &esc_delim
, 2);
579 memcpy(skb_put(skb
, 2), &esc_esc
, 2);
582 memcpy(skb_put(skb
, 1), &c
, 1);
586 static bool valid_packet_type(u8 type
)
589 case HCI_ACLDATA_PKT
:
590 case HCI_COMMAND_PKT
:
591 case HCI_SCODATA_PKT
:
592 case HCI_3WIRE_LINK_PKT
:
593 case HCI_3WIRE_ACK_PKT
:
600 static struct sk_buff
*h5_prepare_pkt(struct hci_uart
*hu
, u8 pkt_type
,
601 const u8
*data
, size_t len
)
603 struct h5
*h5
= hu
->priv
;
604 struct sk_buff
*nskb
;
608 if (!valid_packet_type(pkt_type
)) {
609 BT_ERR("Unknown packet type %u", pkt_type
);
614 * Max len of packet: (original len + 4 (H5 hdr) + 2 (crc)) * 2
615 * (because bytes 0xc0 and 0xdb are escaped, worst case is when
616 * the packet is all made of 0xc0 and 0xdb) + 2 (0xc0
617 * delimiters at start and end).
619 nskb
= alloc_skb((len
+ 6) * 2 + 2, GFP_ATOMIC
);
623 bt_cb(nskb
)->pkt_type
= pkt_type
;
627 hdr
[0] = h5
->tx_ack
<< 3;
628 clear_bit(H5_TX_ACK_REQ
, &h5
->flags
);
630 /* Reliable packet? */
631 if (pkt_type
== HCI_ACLDATA_PKT
|| pkt_type
== HCI_COMMAND_PKT
) {
633 hdr
[0] |= h5
->tx_seq
;
634 h5
->tx_seq
= (h5
->tx_seq
+ 1) % 8;
637 hdr
[1] = pkt_type
| ((len
& 0x0f) << 4);
639 hdr
[3] = ~((hdr
[0] + hdr
[1] + hdr
[2]) & 0xff);
641 BT_DBG("%s tx: seq %u ack %u crc %u rel %u type %u len %u",
642 hu
->hdev
->name
, H5_HDR_SEQ(hdr
), H5_HDR_ACK(hdr
),
643 H5_HDR_CRC(hdr
), H5_HDR_RELIABLE(hdr
), H5_HDR_PKT_TYPE(hdr
),
646 for (i
= 0; i
< 4; i
++)
647 h5_slip_one_byte(nskb
, hdr
[i
]);
649 for (i
= 0; i
< len
; i
++)
650 h5_slip_one_byte(nskb
, data
[i
]);
657 static struct sk_buff
*h5_dequeue(struct hci_uart
*hu
)
659 struct h5
*h5
= hu
->priv
;
661 struct sk_buff
*skb
, *nskb
;
663 if (h5
->sleep
!= H5_AWAKE
) {
664 const unsigned char wakeup_req
[] = { 0x05, 0xfa };
666 if (h5
->sleep
== H5_WAKING_UP
)
669 h5
->sleep
= H5_WAKING_UP
;
670 BT_DBG("Sending wakeup request");
672 mod_timer(&h5
->timer
, jiffies
+ HZ
/ 100);
673 return h5_prepare_pkt(hu
, HCI_3WIRE_LINK_PKT
, wakeup_req
, 2);
676 if ((skb
= skb_dequeue(&h5
->unrel
)) != NULL
) {
677 nskb
= h5_prepare_pkt(hu
, bt_cb(skb
)->pkt_type
,
678 skb
->data
, skb
->len
);
684 skb_queue_head(&h5
->unrel
, skb
);
685 BT_ERR("Could not dequeue pkt because alloc_skb failed");
688 spin_lock_irqsave_nested(&h5
->unack
.lock
, flags
, SINGLE_DEPTH_NESTING
);
690 if (h5
->unack
.qlen
>= h5
->tx_win
)
693 if ((skb
= skb_dequeue(&h5
->rel
)) != NULL
) {
694 nskb
= h5_prepare_pkt(hu
, bt_cb(skb
)->pkt_type
,
695 skb
->data
, skb
->len
);
697 __skb_queue_tail(&h5
->unack
, skb
);
698 mod_timer(&h5
->timer
, jiffies
+ H5_ACK_TIMEOUT
);
699 spin_unlock_irqrestore(&h5
->unack
.lock
, flags
);
703 skb_queue_head(&h5
->rel
, skb
);
704 BT_ERR("Could not dequeue pkt because alloc_skb failed");
708 spin_unlock_irqrestore(&h5
->unack
.lock
, flags
);
710 if (test_bit(H5_TX_ACK_REQ
, &h5
->flags
))
711 return h5_prepare_pkt(hu
, HCI_3WIRE_ACK_PKT
, NULL
, 0);
716 static int h5_flush(struct hci_uart
*hu
)
722 static struct hci_uart_proto h5p
= {
723 .id
= HCI_UART_3WIRE
,
727 .enqueue
= h5_enqueue
,
728 .dequeue
= h5_dequeue
,
732 int __init
h5_init(void)
734 int err
= hci_uart_register_proto(&h5p
);
737 BT_INFO("HCI Three-wire UART (H5) protocol initialized");
739 BT_ERR("HCI Three-wire UART (H5) protocol init failed");
744 int __exit
h5_deinit(void)
746 return hci_uart_unregister_proto(&h5p
);
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