1 // SPDX-License-Identifier: GPL-2.0-or-later
4 * Bluetooth HCI UART driver
6 * Copyright (C) 2002-2003 Fabrizio Gennari <fabrizio.gennari@philips.com>
7 * Copyright (C) 2004-2005 Marcel Holtmann <marcel@holtmann.org>
10 #include <linux/module.h>
12 #include <linux/kernel.h>
13 #include <linux/init.h>
14 #include <linux/types.h>
15 #include <linux/fcntl.h>
16 #include <linux/interrupt.h>
17 #include <linux/ptrace.h>
18 #include <linux/poll.h>
20 #include <linux/slab.h>
21 #include <linux/tty.h>
22 #include <linux/errno.h>
23 #include <linux/string.h>
24 #include <linux/signal.h>
25 #include <linux/ioctl.h>
26 #include <linux/skbuff.h>
27 #include <linux/bitrev.h>
28 #include <asm/unaligned.h>
30 #include <net/bluetooth/bluetooth.h>
31 #include <net/bluetooth/hci_core.h>
35 static bool txcrc
= true;
36 static bool hciextn
= true;
38 #define BCSP_TXWINSIZE 4
40 #define BCSP_ACK_PKT 0x05
41 #define BCSP_LE_PKT 0x06
44 struct sk_buff_head unack
; /* Unack'ed packets queue */
45 struct sk_buff_head rel
; /* Reliable packets queue */
46 struct sk_buff_head unrel
; /* Unreliable packets queue */
48 unsigned long rx_count
;
49 struct sk_buff
*rx_skb
;
50 u8 rxseq_txack
; /* rxseq == txack. */
51 u8 rxack
; /* Last packet sent by us that the peer ack'ed */
52 struct timer_list tbcsp
;
56 BCSP_W4_PKT_DELIMITER
,
70 u8 txack_req
; /* Do we need to send ack's to the peer? */
72 /* Reliable packet sequence number - used to assign seq to each rel pkt. */
76 /* ---- BCSP CRC calculation ---- */
78 /* Table for calculating CRC for polynomial 0x1021, LSB processed first,
79 * initial value 0xffff, bits shifted in reverse order.
82 static const u16 crc_table
[] = {
83 0x0000, 0x1081, 0x2102, 0x3183,
84 0x4204, 0x5285, 0x6306, 0x7387,
85 0x8408, 0x9489, 0xa50a, 0xb58b,
86 0xc60c, 0xd68d, 0xe70e, 0xf78f
89 /* Initialise the crc calculator */
90 #define BCSP_CRC_INIT(x) x = 0xffff
92 /* Update crc with next data byte
95 * The data byte is treated as two nibbles. The crc is generated
96 * in reverse, i.e., bits are fed into the register from the top.
98 static void bcsp_crc_update(u16
*crc
, u8 d
)
102 reg
= (reg
>> 4) ^ crc_table
[(reg
^ d
) & 0x000f];
103 reg
= (reg
>> 4) ^ crc_table
[(reg
^ (d
>> 4)) & 0x000f];
108 /* ---- BCSP core ---- */
110 static void bcsp_slip_msgdelim(struct sk_buff
*skb
)
112 const char pkt_delim
= 0xc0;
114 skb_put_data(skb
, &pkt_delim
, 1);
117 static void bcsp_slip_one_byte(struct sk_buff
*skb
, u8 c
)
119 const char esc_c0
[2] = { 0xdb, 0xdc };
120 const char esc_db
[2] = { 0xdb, 0xdd };
124 skb_put_data(skb
, &esc_c0
, 2);
127 skb_put_data(skb
, &esc_db
, 2);
130 skb_put_data(skb
, &c
, 1);
134 static int bcsp_enqueue(struct hci_uart
*hu
, struct sk_buff
*skb
)
136 struct bcsp_struct
*bcsp
= hu
->priv
;
138 if (skb
->len
> 0xFFF) {
139 BT_ERR("Packet too long");
144 switch (hci_skb_pkt_type(skb
)) {
145 case HCI_ACLDATA_PKT
:
146 case HCI_COMMAND_PKT
:
147 skb_queue_tail(&bcsp
->rel
, skb
);
150 case HCI_SCODATA_PKT
:
151 skb_queue_tail(&bcsp
->unrel
, skb
);
155 BT_ERR("Unknown packet type");
163 static struct sk_buff
*bcsp_prepare_pkt(struct bcsp_struct
*bcsp
, u8
*data
,
164 int len
, int pkt_type
)
166 struct sk_buff
*nskb
;
168 u16
BCSP_CRC_INIT(bcsp_txmsg_crc
);
172 case HCI_ACLDATA_PKT
:
173 chan
= 6; /* BCSP ACL channel */
174 rel
= 1; /* reliable channel */
176 case HCI_COMMAND_PKT
:
177 chan
= 5; /* BCSP cmd/evt channel */
178 rel
= 1; /* reliable channel */
180 case HCI_SCODATA_PKT
:
181 chan
= 7; /* BCSP SCO channel */
182 rel
= 0; /* unreliable channel */
185 chan
= 1; /* BCSP LE channel */
186 rel
= 0; /* unreliable channel */
189 chan
= 0; /* BCSP internal channel */
190 rel
= 0; /* unreliable channel */
193 BT_ERR("Unknown packet type");
197 if (hciextn
&& chan
== 5) {
198 __le16 opcode
= ((struct hci_command_hdr
*)data
)->opcode
;
200 /* Vendor specific commands */
201 if (hci_opcode_ogf(__le16_to_cpu(opcode
)) == 0x3f) {
202 u8 desc
= *(data
+ HCI_COMMAND_HDR_SIZE
);
204 if ((desc
& 0xf0) == 0xc0) {
205 data
+= HCI_COMMAND_HDR_SIZE
+ 1;
206 len
-= HCI_COMMAND_HDR_SIZE
+ 1;
212 /* Max len of packet: (original len +4(bcsp hdr) +2(crc))*2
213 * (because bytes 0xc0 and 0xdb are escaped, worst case is
214 * when the packet is all made of 0xc0 and 0xdb :) )
215 * + 2 (0xc0 delimiters at start and end).
218 nskb
= alloc_skb((len
+ 6) * 2 + 2, GFP_ATOMIC
);
222 hci_skb_pkt_type(nskb
) = pkt_type
;
224 bcsp_slip_msgdelim(nskb
);
226 hdr
[0] = bcsp
->rxseq_txack
<< 3;
228 BT_DBG("We request packet no %u to card", bcsp
->rxseq_txack
);
231 hdr
[0] |= 0x80 + bcsp
->msgq_txseq
;
232 BT_DBG("Sending packet with seqno %u", bcsp
->msgq_txseq
);
233 bcsp
->msgq_txseq
= (bcsp
->msgq_txseq
+ 1) & 0x07;
239 hdr
[1] = ((len
<< 4) & 0xff) | chan
;
241 hdr
[3] = ~(hdr
[0] + hdr
[1] + hdr
[2]);
243 /* Put BCSP header */
244 for (i
= 0; i
< 4; i
++) {
245 bcsp_slip_one_byte(nskb
, hdr
[i
]);
248 bcsp_crc_update(&bcsp_txmsg_crc
, hdr
[i
]);
252 for (i
= 0; i
< len
; i
++) {
253 bcsp_slip_one_byte(nskb
, data
[i
]);
256 bcsp_crc_update(&bcsp_txmsg_crc
, data
[i
]);
261 bcsp_txmsg_crc
= bitrev16(bcsp_txmsg_crc
);
262 bcsp_slip_one_byte(nskb
, (u8
)((bcsp_txmsg_crc
>> 8) & 0x00ff));
263 bcsp_slip_one_byte(nskb
, (u8
)(bcsp_txmsg_crc
& 0x00ff));
266 bcsp_slip_msgdelim(nskb
);
270 /* This is a rewrite of pkt_avail in ABCSP */
271 static struct sk_buff
*bcsp_dequeue(struct hci_uart
*hu
)
273 struct bcsp_struct
*bcsp
= hu
->priv
;
277 /* First of all, check for unreliable messages in the queue,
278 * since they have priority
281 skb
= skb_dequeue(&bcsp
->unrel
);
283 struct sk_buff
*nskb
;
285 nskb
= bcsp_prepare_pkt(bcsp
, skb
->data
, skb
->len
,
286 hci_skb_pkt_type(skb
));
291 skb_queue_head(&bcsp
->unrel
, skb
);
292 BT_ERR("Could not dequeue pkt because alloc_skb failed");
296 /* Now, try to send a reliable pkt. We can only send a
297 * reliable packet if the number of packets sent but not yet ack'ed
298 * is < than the winsize
301 spin_lock_irqsave_nested(&bcsp
->unack
.lock
, flags
, SINGLE_DEPTH_NESTING
);
303 if (bcsp
->unack
.qlen
< BCSP_TXWINSIZE
) {
304 skb
= skb_dequeue(&bcsp
->rel
);
306 struct sk_buff
*nskb
;
308 nskb
= bcsp_prepare_pkt(bcsp
, skb
->data
, skb
->len
,
309 hci_skb_pkt_type(skb
));
311 __skb_queue_tail(&bcsp
->unack
, skb
);
312 mod_timer(&bcsp
->tbcsp
, jiffies
+ HZ
/ 4);
313 spin_unlock_irqrestore(&bcsp
->unack
.lock
, flags
);
316 skb_queue_head(&bcsp
->rel
, skb
);
317 BT_ERR("Could not dequeue pkt because alloc_skb failed");
322 spin_unlock_irqrestore(&bcsp
->unack
.lock
, flags
);
324 /* We could not send a reliable packet, either because there are
325 * none or because there are too many unack'ed pkts. Did we receive
326 * any packets we have not acknowledged yet ?
329 if (bcsp
->txack_req
) {
330 /* if so, craft an empty ACK pkt and send it on BCSP unreliable
333 struct sk_buff
*nskb
= bcsp_prepare_pkt(bcsp
, NULL
, 0, BCSP_ACK_PKT
);
337 /* We have nothing to send */
341 static int bcsp_flush(struct hci_uart
*hu
)
347 /* Remove ack'ed packets */
348 static void bcsp_pkt_cull(struct bcsp_struct
*bcsp
)
350 struct sk_buff
*skb
, *tmp
;
352 int i
, pkts_to_be_removed
;
355 spin_lock_irqsave(&bcsp
->unack
.lock
, flags
);
357 pkts_to_be_removed
= skb_queue_len(&bcsp
->unack
);
358 seqno
= bcsp
->msgq_txseq
;
360 while (pkts_to_be_removed
) {
361 if (bcsp
->rxack
== seqno
)
363 pkts_to_be_removed
--;
364 seqno
= (seqno
- 1) & 0x07;
367 if (bcsp
->rxack
!= seqno
)
368 BT_ERR("Peer acked invalid packet");
370 BT_DBG("Removing %u pkts out of %u, up to seqno %u",
371 pkts_to_be_removed
, skb_queue_len(&bcsp
->unack
),
375 skb_queue_walk_safe(&bcsp
->unack
, skb
, tmp
) {
376 if (i
>= pkts_to_be_removed
)
380 __skb_unlink(skb
, &bcsp
->unack
);
384 if (skb_queue_empty(&bcsp
->unack
))
385 del_timer(&bcsp
->tbcsp
);
387 spin_unlock_irqrestore(&bcsp
->unack
.lock
, flags
);
389 if (i
!= pkts_to_be_removed
)
390 BT_ERR("Removed only %u out of %u pkts", i
, pkts_to_be_removed
);
393 /* Handle BCSP link-establishment packets. When we
394 * detect a "sync" packet, symptom that the BT module has reset,
395 * we do nothing :) (yet)
397 static void bcsp_handle_le_pkt(struct hci_uart
*hu
)
399 struct bcsp_struct
*bcsp
= hu
->priv
;
400 u8 conf_pkt
[4] = { 0xad, 0xef, 0xac, 0xed };
401 u8 conf_rsp_pkt
[4] = { 0xde, 0xad, 0xd0, 0xd0 };
402 u8 sync_pkt
[4] = { 0xda, 0xdc, 0xed, 0xed };
404 /* spot "conf" pkts and reply with a "conf rsp" pkt */
405 if (bcsp
->rx_skb
->data
[1] >> 4 == 4 && bcsp
->rx_skb
->data
[2] == 0 &&
406 !memcmp(&bcsp
->rx_skb
->data
[4], conf_pkt
, 4)) {
407 struct sk_buff
*nskb
= alloc_skb(4, GFP_ATOMIC
);
409 BT_DBG("Found a LE conf pkt");
412 skb_put_data(nskb
, conf_rsp_pkt
, 4);
413 hci_skb_pkt_type(nskb
) = BCSP_LE_PKT
;
415 skb_queue_head(&bcsp
->unrel
, nskb
);
416 hci_uart_tx_wakeup(hu
);
418 /* Spot "sync" pkts. If we find one...disaster! */
419 else if (bcsp
->rx_skb
->data
[1] >> 4 == 4 && bcsp
->rx_skb
->data
[2] == 0 &&
420 !memcmp(&bcsp
->rx_skb
->data
[4], sync_pkt
, 4)) {
421 BT_ERR("Found a LE sync pkt, card has reset");
425 static inline void bcsp_unslip_one_byte(struct bcsp_struct
*bcsp
, unsigned char byte
)
427 const u8 c0
= 0xc0, db
= 0xdb;
429 switch (bcsp
->rx_esc_state
) {
430 case BCSP_ESCSTATE_NOESC
:
433 bcsp
->rx_esc_state
= BCSP_ESCSTATE_ESC
;
436 skb_put_data(bcsp
->rx_skb
, &byte
, 1);
437 if ((bcsp
->rx_skb
->data
[0] & 0x40) != 0 &&
438 bcsp
->rx_state
!= BCSP_W4_CRC
)
439 bcsp_crc_update(&bcsp
->message_crc
, byte
);
444 case BCSP_ESCSTATE_ESC
:
447 skb_put_data(bcsp
->rx_skb
, &c0
, 1);
448 if ((bcsp
->rx_skb
->data
[0] & 0x40) != 0 &&
449 bcsp
->rx_state
!= BCSP_W4_CRC
)
450 bcsp_crc_update(&bcsp
->message_crc
, 0xc0);
451 bcsp
->rx_esc_state
= BCSP_ESCSTATE_NOESC
;
456 skb_put_data(bcsp
->rx_skb
, &db
, 1);
457 if ((bcsp
->rx_skb
->data
[0] & 0x40) != 0 &&
458 bcsp
->rx_state
!= BCSP_W4_CRC
)
459 bcsp_crc_update(&bcsp
->message_crc
, 0xdb);
460 bcsp
->rx_esc_state
= BCSP_ESCSTATE_NOESC
;
465 BT_ERR("Invalid byte %02x after esc byte", byte
);
466 kfree_skb(bcsp
->rx_skb
);
468 bcsp
->rx_state
= BCSP_W4_PKT_DELIMITER
;
474 static void bcsp_complete_rx_pkt(struct hci_uart
*hu
)
476 struct bcsp_struct
*bcsp
= hu
->priv
;
479 if (bcsp
->rx_skb
->data
[0] & 0x80) { /* reliable pkt */
480 BT_DBG("Received seqno %u from card", bcsp
->rxseq_txack
);
482 /* check the rx sequence number is as expected */
483 if ((bcsp
->rx_skb
->data
[0] & 0x07) == bcsp
->rxseq_txack
) {
485 bcsp
->rxseq_txack
%= 0x8;
487 /* handle re-transmitted packet or
488 * when packet was missed
490 BT_ERR("Out-of-order packet arrived, got %u expected %u",
491 bcsp
->rx_skb
->data
[0] & 0x07, bcsp
->rxseq_txack
);
493 /* do not process out-of-order packet payload */
497 /* send current txack value to all received reliable packets */
500 /* If needed, transmit an ack pkt */
501 hci_uart_tx_wakeup(hu
);
504 bcsp
->rxack
= (bcsp
->rx_skb
->data
[0] >> 3) & 0x07;
505 BT_DBG("Request for pkt %u from card", bcsp
->rxack
);
507 /* handle received ACK indications,
508 * including those from out-of-order packets
513 if ((bcsp
->rx_skb
->data
[1] & 0x0f) == 6 &&
514 (bcsp
->rx_skb
->data
[0] & 0x80)) {
515 hci_skb_pkt_type(bcsp
->rx_skb
) = HCI_ACLDATA_PKT
;
517 } else if ((bcsp
->rx_skb
->data
[1] & 0x0f) == 5 &&
518 (bcsp
->rx_skb
->data
[0] & 0x80)) {
519 hci_skb_pkt_type(bcsp
->rx_skb
) = HCI_EVENT_PKT
;
521 } else if ((bcsp
->rx_skb
->data
[1] & 0x0f) == 7) {
522 hci_skb_pkt_type(bcsp
->rx_skb
) = HCI_SCODATA_PKT
;
524 } else if ((bcsp
->rx_skb
->data
[1] & 0x0f) == 1 &&
525 !(bcsp
->rx_skb
->data
[0] & 0x80)) {
526 bcsp_handle_le_pkt(hu
);
534 struct hci_event_hdr hdr
;
535 u8 desc
= (bcsp
->rx_skb
->data
[1] & 0x0f);
537 if (desc
!= 0 && desc
!= 1) {
540 skb_pull(bcsp
->rx_skb
, 4);
541 memcpy(skb_push(bcsp
->rx_skb
, 1), &desc
, 1);
544 hdr
.plen
= bcsp
->rx_skb
->len
;
545 memcpy(skb_push(bcsp
->rx_skb
, HCI_EVENT_HDR_SIZE
), &hdr
, HCI_EVENT_HDR_SIZE
);
546 hci_skb_pkt_type(bcsp
->rx_skb
) = HCI_EVENT_PKT
;
548 hci_recv_frame(hu
->hdev
, bcsp
->rx_skb
);
550 BT_ERR("Packet for unknown channel (%u %s)",
551 bcsp
->rx_skb
->data
[1] & 0x0f,
552 bcsp
->rx_skb
->data
[0] & 0x80 ?
553 "reliable" : "unreliable");
554 kfree_skb(bcsp
->rx_skb
);
557 kfree_skb(bcsp
->rx_skb
);
558 } else if (pass_up
== 1) {
559 /* Pull out BCSP hdr */
560 skb_pull(bcsp
->rx_skb
, 4);
562 hci_recv_frame(hu
->hdev
, bcsp
->rx_skb
);
564 /* ignore packet payload of already ACKed re-transmitted
565 * packets or when a packet was missed in the BCSP window
567 kfree_skb(bcsp
->rx_skb
);
570 bcsp
->rx_state
= BCSP_W4_PKT_DELIMITER
;
574 static u16
bscp_get_crc(struct bcsp_struct
*bcsp
)
576 return get_unaligned_be16(&bcsp
->rx_skb
->data
[bcsp
->rx_skb
->len
- 2]);
580 static int bcsp_recv(struct hci_uart
*hu
, const void *data
, int count
)
582 struct bcsp_struct
*bcsp
= hu
->priv
;
583 const unsigned char *ptr
;
585 BT_DBG("hu %p count %d rx_state %d rx_count %ld",
586 hu
, count
, bcsp
->rx_state
, bcsp
->rx_count
);
590 if (bcsp
->rx_count
) {
592 BT_ERR("Short BCSP packet");
593 kfree_skb(bcsp
->rx_skb
);
595 bcsp
->rx_state
= BCSP_W4_PKT_START
;
598 bcsp_unslip_one_byte(bcsp
, *ptr
);
604 switch (bcsp
->rx_state
) {
605 case BCSP_W4_BCSP_HDR
:
606 if ((0xff & (u8
)~(bcsp
->rx_skb
->data
[0] + bcsp
->rx_skb
->data
[1] +
607 bcsp
->rx_skb
->data
[2])) != bcsp
->rx_skb
->data
[3]) {
608 BT_ERR("Error in BCSP hdr checksum");
609 kfree_skb(bcsp
->rx_skb
);
611 bcsp
->rx_state
= BCSP_W4_PKT_DELIMITER
;
615 bcsp
->rx_state
= BCSP_W4_DATA
;
616 bcsp
->rx_count
= (bcsp
->rx_skb
->data
[1] >> 4) +
617 (bcsp
->rx_skb
->data
[2] << 4); /* May be 0 */
621 if (bcsp
->rx_skb
->data
[0] & 0x40) { /* pkt with crc */
622 bcsp
->rx_state
= BCSP_W4_CRC
;
625 bcsp_complete_rx_pkt(hu
);
629 if (bitrev16(bcsp
->message_crc
) != bscp_get_crc(bcsp
)) {
630 BT_ERR("Checksum failed: computed %04x received %04x",
631 bitrev16(bcsp
->message_crc
),
634 kfree_skb(bcsp
->rx_skb
);
636 bcsp
->rx_state
= BCSP_W4_PKT_DELIMITER
;
640 skb_trim(bcsp
->rx_skb
, bcsp
->rx_skb
->len
- 2);
641 bcsp_complete_rx_pkt(hu
);
644 case BCSP_W4_PKT_DELIMITER
:
647 bcsp
->rx_state
= BCSP_W4_PKT_START
;
650 /*BT_ERR("Ignoring byte %02x", *ptr);*/
656 case BCSP_W4_PKT_START
:
663 bcsp
->rx_state
= BCSP_W4_BCSP_HDR
;
665 bcsp
->rx_esc_state
= BCSP_ESCSTATE_NOESC
;
666 BCSP_CRC_INIT(bcsp
->message_crc
);
668 /* Do not increment ptr or decrement count
669 * Allocate packet. Max len of a BCSP pkt=
670 * 0xFFF (payload) +4 (header) +2 (crc)
673 bcsp
->rx_skb
= bt_skb_alloc(0x1005, GFP_ATOMIC
);
675 BT_ERR("Can't allocate mem for new packet");
676 bcsp
->rx_state
= BCSP_W4_PKT_DELIMITER
;
688 /* Arrange to retransmit all messages in the relq. */
689 static void bcsp_timed_event(struct timer_list
*t
)
691 struct bcsp_struct
*bcsp
= from_timer(bcsp
, t
, tbcsp
);
692 struct hci_uart
*hu
= bcsp
->hu
;
696 BT_DBG("hu %p retransmitting %u pkts", hu
, bcsp
->unack
.qlen
);
698 spin_lock_irqsave_nested(&bcsp
->unack
.lock
, flags
, SINGLE_DEPTH_NESTING
);
700 while ((skb
= __skb_dequeue_tail(&bcsp
->unack
)) != NULL
) {
701 bcsp
->msgq_txseq
= (bcsp
->msgq_txseq
- 1) & 0x07;
702 skb_queue_head(&bcsp
->rel
, skb
);
705 spin_unlock_irqrestore(&bcsp
->unack
.lock
, flags
);
707 hci_uart_tx_wakeup(hu
);
710 static int bcsp_open(struct hci_uart
*hu
)
712 struct bcsp_struct
*bcsp
;
716 bcsp
= kzalloc(sizeof(*bcsp
), GFP_KERNEL
);
722 skb_queue_head_init(&bcsp
->unack
);
723 skb_queue_head_init(&bcsp
->rel
);
724 skb_queue_head_init(&bcsp
->unrel
);
726 timer_setup(&bcsp
->tbcsp
, bcsp_timed_event
, 0);
728 bcsp
->rx_state
= BCSP_W4_PKT_DELIMITER
;
736 static int bcsp_close(struct hci_uart
*hu
)
738 struct bcsp_struct
*bcsp
= hu
->priv
;
740 del_timer_sync(&bcsp
->tbcsp
);
746 skb_queue_purge(&bcsp
->unack
);
747 skb_queue_purge(&bcsp
->rel
);
748 skb_queue_purge(&bcsp
->unrel
);
751 kfree_skb(bcsp
->rx_skb
);
759 static const struct hci_uart_proto bcsp
= {
764 .enqueue
= bcsp_enqueue
,
765 .dequeue
= bcsp_dequeue
,
770 int __init
bcsp_init(void)
772 return hci_uart_register_proto(&bcsp
);
775 int __exit
bcsp_deinit(void)
777 return hci_uart_unregister_proto(&bcsp
);
780 module_param(txcrc
, bool, 0644);
781 MODULE_PARM_DESC(txcrc
, "Transmit CRC with every BCSP packet");
783 module_param(hciextn
, bool, 0644);
784 MODULE_PARM_DESC(hciextn
, "Convert HCI Extensions into BCSP packets");