935<
static int bcsp_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
	struct bcsp_struct *bcsp = hu->priv;

	if (skb->len > 0xFFF) {
		BT_ERR("Packet too long");
		kfree_skb(skb);
		return 0;
	}

	switch (bt_cb(skb)->pkt_type) {
	case HCI_ACLDATA_PKT:
	case HCI_COMMAND_PKT:
		skb_queue_tail(&bcsp->rel, skb);
		break;

	case HCI_SCODATA_PKT:
		skb_queue_tail(&bcsp->unrel, skb);
		break;

	default:
		BT_ERR("Unknown packet type");
		kfree_skb(skb);
		break;
	}

	return 0;
}

static struct sk_buff *bcsp_prepare_pkt(struct bcsp_struct *bcsp, u8 *data,
		int len, int pkt_type)
{
	struct sk_buff *nskb;
	u8 hdr[4], chan;
	u16 BCSP_CRC_INIT(bcsp_txmsg_crc);
	int rel, i;

	switch (pkt_type) {
	case HCI_ACLDATA_PKT:
		chan = 6;	/* BCSP ACL channel */
		rel = 1;	/* reliable channel */
		break;
	case HCI_COMMAND_PKT:
		chan = 5;	/* BCSP cmd/evt channel */
		rel = 1;	/* reliable channel */
		break;
	case HCI_SCODATA_PKT:
		chan = 7;	/* BCSP SCO channel */
		rel = 0;	/* unreliable channel */
		break;
	case BCSP_LE_PKT:
		chan = 1;	/* BCSP LE channel */
		rel = 0;	/* unreliable channel */
		break;
	case BCSP_ACK_PKT:
		chan = 0;	/* BCSP internal channel */
		rel = 0;	/* unreliable channel */
		break;
	default:
		BT_ERR("Unknown packet type");
		return NULL;
	}

	if (hciextn && chan == 5) {
		struct hci_command_hdr *hdr = (struct hci_command_hdr *) data;

		if (hci_opcode_ogf(__le16_to_cpu(hdr->opcode)) == OGF_VENDOR_CMD) {
			u8 desc = *(data + HCI_COMMAND_HDR_SIZE);
			if ((desc & 0xf0) == 0xc0) {
				data += HCI_COMMAND_HDR_SIZE + 1;
				len  -= HCI_COMMAND_HDR_SIZE + 1;
				chan = desc & 0x0f;
			}
		}
	}

	/* Max len of packet: (original len +4(bcsp hdr) +2(crc))*2
	   (because bytes 0xc0 and 0xdb are escaped, worst case is
	   when the packet is all made of 0xc0 and 0xdb :) )
	   + 2 (0xc0 delimiters at start and end). */

	nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
	if (!nskb)
		return NULL;

	bt_cb(nskb)->pkt_type = pkt_type;

	bcsp_slip_msgdelim(nskb);

	hdr[0] = bcsp->rxseq_txack << 3;
	bcsp->txack_req = 0;
	BT_DBG("We request packet no %u to card", bcsp->rxseq_txack);

	if (rel) {
		hdr[0] |= 0x80 + bcsp->msgq_txseq;
		BT_DBG("Sending packet with seqno %u", bcsp->msgq_txseq);
		bcsp->msgq_txseq = ++(bcsp->msgq_txseq) & 0x07;
	}

	if (bcsp->use_crc)
		hdr[0] |= 0x40;

	hdr[1] = ((len << 4) & 0xff) | chan;
	hdr[2] = len >> 4;
	hdr[3] = ~(hdr[0] + hdr[1] + hdr[2]);

	/* Put BCSP header */
	for (i = 0; i < 4; i++) {
		bcsp_slip_one_byte(nskb, hdr[i]);

		if (bcsp->use_crc)
			bcsp_crc_update(&bcsp_txmsg_crc, hdr[i]);
	}

	/* Put payload */
	for (i = 0; i < len; i++) {
		bcsp_slip_one_byte(nskb, data[i]);

		if (bcsp->use_crc)
			bcsp_crc_update(&bcsp_txmsg_crc, data[i]);
	}

	/* Put CRC */
	if (bcsp->use_crc) {
		bcsp_txmsg_crc = bcsp_crc_reverse(bcsp_txmsg_crc);
		bcsp_slip_one_byte(nskb, (u8) ((bcsp_txmsg_crc >> 8) & 0x00ff));
		bcsp_slip_one_byte(nskb, (u8) (bcsp_txmsg_crc & 0x00ff));
	}

	bcsp_slip_msgdelim(nskb);
	return nskb;
}

/* This is a rewrite of pkt_avail in ABCSP */
static struct sk_buff *bcsp_dequeue(struct hci_uart *hu)
{
	struct bcsp_struct *bcsp = hu->priv;
	unsigned long flags;
	struct sk_buff *skb;
	
	/* First of all, check for unreliable messages in the queue,
	   since they have priority */

	if ((skb = skb_dequeue(&bcsp->unrel)) != NULL) {
		struct sk_buff *nskb = bcsp_prepare_pkt(bcsp, skb->data, skb->len, bt_cb(skb)->pkt_type);
		if (nskb) {
			kfree_skb(skb);
			return nskb;
		} else {
			skb_queue_head(&bcsp->unrel, skb);
			BT_ERR("Could not dequeue pkt because alloc_skb failed");
		}
	}

	/* Now, try to send a reliable pkt. We can only send a
	   reliable packet if the number of packets sent but not yet ack'ed
	   is < than the winsize */

	spin_lock_irqsave(&bcsp->unack.lock, flags);

	if (bcsp->unack.qlen < BCSP_TXWINSIZE && (skb = skb_dequeue(&bcsp->rel)) != NULL) {
		struct sk_buff *nskb = bcsp_prepare_pkt(bcsp, skb->data, skb->len, bt_cb(skb)->pkt_type);
		if (nskb) {
			__skb_queue_tail(&bcsp->unack, skb);
			mod_timer(&bcsp->tbcsp, jiffies + HZ / 4);
			spin_unlock_irqrestore(&bcsp->unack.lock, flags);
			return nskb;
		} else {
			skb_queue_head(&bcsp->rel, skb);
			BT_ERR("Could not dequeue pkt because alloc_skb failed");
		}
	}

	spin_unlock_irqrestore(&bcsp->unack.lock, flags);


	/* We could not send a reliable packet, either because there are
	   none or because there are too many unack'ed pkts. Did we receive
	   any packets we have not acknowledged yet ? */

	if (bcsp->txack_req) {
		/* if so, craft an empty ACK pkt and send it on BCSP unreliable
		   channel 0 */
		struct sk_buff *nskb = bcsp_prepare_pkt(bcsp, NULL, 0, BCSP_ACK_PKT);
		return nskb;
	}

	/* We have nothing to send */
	return NULL;
}

static int bcsp_flush(struct hci_uart *hu)
{
	BT_DBG("hu %p", hu);
	return 0;
}

/* Remove ack'ed packets */
static void bcsp_pkt_cull(struct bcsp_struct *bcsp)
{
	unsigned long flags;
	struct sk_buff *skb;
	int i, pkts_to_be_removed;
	u8 seqno;

	spin_lock_irqsave(&bcsp->unack.lock, flags);

	pkts_to_be_removed = bcsp->unack.qlen;
	seqno = bcsp->msgq_txseq;

	while (pkts_to_be_removed) {
		if (bcsp->rxack == seqno)
			break;
		pkts_to_be_removed--;
		seqno = (seqno - 1) & 0x07;
	}

	if (bcsp->rxack != seqno)
		BT_ERR("Peer acked invalid packet");

	BT_DBG("Removing %u pkts out of %u, up to seqno %u",
	       pkts_to_be_removed, bcsp->unack.qlen, (seqno - 1) & 0x07);

	for (i = 0, skb = ((struct sk_buff *) &bcsp->unack)->next; i < pkts_to_be_removed
			&& skb != (struct sk_buff *) &bcsp->unack; i++) {
		struct sk_buff *nskb;

		nskb = skb->next;
		__skb_unlink(skb, &bcsp->unack);
		kfree_skb(skb);
		skb = nskb;
	}
	if (bcsp->unack.qlen == 0)
		del_timer(&bcsp->tbcsp);
	spin_unlock_irqrestore(&bcsp->unack.lock, flags);

	if (i != pkts_to_be_removed)
		BT_ERR("Removed only %u out of %u pkts", i, pkts_to_be_removed);
}

/* Handle BCSP link-establishment packets. When we
   detect a "sync" packet, symptom that the BT module has reset,
   we do nothing :) (yet) */
static void bcsp_handle_le_pkt(struct hci_uart *hu)
{
	struct bcsp_struct *bcsp = hu->priv;
	u8 conf_pkt[4]     = { 0xad, 0xef, 0xac, 0xed };
	u8 conf_rsp_pkt[4] = { 0xde, 0xad, 0xd0, 0xd0 };
	u8 sync_pkt[4]     = { 0xda, 0xdc, 0xed, 0xed };

	/* spot "conf" pkts and reply with a "conf rsp" pkt */
	if (bcsp->rx_skb->data[1] >> 4 == 4 && bcsp->rx_skb->data[2] == 0 &&
			!memcmp(&bcsp->rx_skb->data[4], conf_pkt, 4)) {
		struct sk_buff *nskb = alloc_skb(4, GFP_ATOMIC);

		BT_DBG("Found a LE conf pkt");
		if (!nskb)
			return;
		memcpy(skb_put(nskb, 4), conf_rsp_pkt, 4);
		bt_cb(nskb)->pkt_type = BCSP_LE_PKT;

		skb_queue_head(&bcsp->unrel, nskb);
		hci_uart_tx_wakeup(hu);
	}
	/* Spot "sync" pkts. If we find one...disaster! */
	else if (bcsp->rx_skb->data[1] >> 4 == 4 && bcsp->rx_skb->data[2] == 0 &&
			!memcmp(&bcsp->rx_skb->data[4], sync_pkt, 4)) {
		BT_ERR("Found a LE sync pkt, card has reset");
	}
}

static inline void bcsp_unslip_one_byte(struct bcsp_struct *bcsp, unsigned char byte)
{
	const u8 c0 = 0xc0, db = 0xdb;

	switch (bcsp->rx_esc_state) {
	case BCSP_ESCSTATE_NOESC:
		switch (byte) {
		case 0xdb:
			bcsp->rx_esc_state = BCSP_ESCSTATE_ESC;
			break;
		default:
			memcpy(skb_put(bcsp->rx_skb, 1), &byte, 1);
			if ((bcsp->rx_skb-> data[0] & 0x40) != 0 && 
					bcsp->rx_state != BCSP_W4_CRC)
				bcsp_crc_update(&bcsp->message_crc, byte);
			bcsp->rx_count--;
		}
		break;

	case BCSP_ESCSTATE_ESC:
		switch (byte) {
		case 0xdc:
			memcpy(skb_put(bcsp->rx_skb, 1), &c0, 1);
			if ((bcsp->rx_skb-> data[0] & 0x40) != 0 && 
					bcsp->rx_state != BCSP_W4_CRC)
				bcsp_crc_update(&bcsp-> message_crc, 0xc0);
			bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
			bcsp->rx_count--;
			break;

		case 0xdd:
			memcpy(skb_put(bcsp->rx_skb, 1), &db, 1);
			if ((bcsp->rx_skb-> data[0] & 0x40) != 0 && 
					bcsp->rx_state != BCSP_W4_CRC) 
				bcsp_crc_update(&bcsp-> message_crc, 0xdb);
			bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
			bcsp->rx_count--;
			break;

		default:
			BT_ERR ("Invalid byte %02x after esc byte", byte);
			kfree_skb(bcsp->rx_skb);
			bcsp->rx_skb = NULL;
			bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
			bcsp->rx_count = 0;
		}
	}
}

static inline void bcsp_complete_rx_pkt(struct hci_uart *hu)
{
	struct bcsp_struct *bcsp = hu->priv;
	int pass_up;

	if (bcsp->rx_skb->data[0] & 0x80) {	/* reliable pkt */
		BT_DBG("Received seqno %u from card", bcsp->rxseq_txack);
		bcsp->rxseq_txack++;
		bcsp->rxseq_txack %= 0x8;
		bcsp->txack_req    = 1;

		/* If needed, transmit an ack pkt */
		hci_uart_tx_wakeup(hu);
	}

	bcsp->rxack = (bcsp->rx_skb->data[0] >> 3) & 0x07;
	BT_DBG("Request for pkt %u from card", bcsp->rxack);

	bcsp_pkt_cull(bcsp);
	if ((bcsp->rx_skb->data[1] & 0x0f) == 6 &&
			bcsp->rx_skb->data[0] & 0x80) {
		bt_cb(bcsp->rx_skb)->pkt_type = HCI_ACLDATA_PKT;
		pass_up = 1;
	} else if ((bcsp->rx_skb->data[1] & 0x0f) == 5 &&
			bcsp->rx_skb->data[0] & 0x80) {
		bt_cb(bcsp->rx_skb)->pkt_type = HCI_EVENT_PKT;
		pass_up = 1;
	} else if ((bcsp->rx_skb->data[1] & 0x0f) == 7) {
		bt_cb(bcsp->rx_skb)->pkt_type = HCI_SCODATA_PKT;
		pass_up = 1;
	} else if ((bcsp->rx_skb->data[1] & 0x0f) == 1 &&
			!(bcsp->rx_skb->data[0] & 0x80)) {
		bcsp_handle_le_pkt(hu);
		pass_up = 0;
	} else
		pass_up = 0;

	if (!pass_up) {
		struct hci_event_hdr hdr;
		u8 desc = (bcsp->rx_skb->data[1] & 0x0f);

		if (desc != 0 && desc != 1) {
			if (hciextn) {
				desc |= 0xc0;
				skb_pull(bcsp->rx_skb, 4);
				memcpy(skb_push(bcsp->rx_skb, 1), &desc, 1);

				hdr.evt = 0xff;
				hdr.plen = bcsp->rx_skb->len;
				memcpy(skb_push(bcsp->rx_skb, HCI_EVENT_HDR_SIZE), &hdr, HCI_EVENT_HDR_SIZE);
				bt_cb(bcsp->rx_skb)->pkt_type = HCI_EVENT_PKT;

				hci_recv_frame(bcsp->rx_skb);
			} else {
				BT_ERR ("Packet for unknown channel (%u %s)",
					bcsp->rx_skb->data[1] & 0x0f,
					bcsp->rx_skb->data[0] & 0x80 ? 
					"reliable" : "unreliable");
				kfree_skb(bcsp->rx_skb);
			}
		} else
			kfree_skb(bcsp->rx_skb);
	} else {
		/* Pull out BCSP hdr */
		skb_pull(bcsp->rx_skb, 4);

		hci_recv_frame(bcsp->rx_skb);
	}
	bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
	bcsp->rx_skb = NULL;
}

/* Recv data */
static int bcsp_recv(struct hci_uart *hu, void *data, int count)
{
	struct bcsp_struct *bcsp = hu->priv;
	register unsigned char *ptr;

	BT_DBG("hu %p count %d rx_state %d rx_count %ld", 
		hu, count, bcsp->rx_state, bcsp->rx_count);

	ptr = data;
	while (count) {
		if (bcsp->rx_count) {
			if (*ptr == 0xc0) {
				BT_ERR("Short BCSP packet");
				kfree_skb(bcsp->rx_skb);
				bcsp->rx_state = BCSP_W4_PKT_START;
				bcsp->rx_count = 0;
			} else
				bcsp_unslip_one_byte(bcsp, *ptr);

			ptr++; count--;
			continue;
		}

		switch (bcsp->rx_state) {
		case BCSP_W4_BCSP_HDR:
			if ((0xff & (u8) ~ (bcsp->rx_skb->data[0] + bcsp->rx_skb->data[1] +
					bcsp->rx_skb->data[2])) != bcsp->rx_skb->data[3]) {
				BT_ERR("Error in BCSP hdr checksum");
				kfree_skb(bcsp->rx_skb);
				bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
				bcsp->rx_count = 0;
				continue;
			}
			if (bcsp->rx_skb->data[0] & 0x80	/* reliable pkt */
			    		&& (bcsp->rx_skb->data[0] & 0x07) != bcsp->rxseq_txack) {
				BT_ERR ("Out-of-order packet arrived, got %u expected %u",
					bcsp->rx_skb->data[0] & 0x07, bcsp->rxseq_txack);

				kfree_skb(bcsp->rx_skb);
				bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
				bcsp->rx_count = 0;
				continue;
			}
			bcsp->rx_state = BCSP_W4_DATA;
			bcsp->rx_count = (bcsp->rx_skb->data[1] >> 4) + 
					(bcsp->rx_skb->data[2] << 4);	/* May be 0 */
			continue;

		case BCSP_W4_DATA:
			if (bcsp->rx_skb->data[0] & 0x40) {	/* pkt with crc */
				bcsp->rx_state = BCSP_W4_CRC;
				bcsp->rx_count = 2;
			} else
				bcsp_complete_rx_pkt(hu);
			continue;

		case BCSP_W4_CRC:
			if (bcsp_crc_reverse(bcsp->message_crc) !=
					(bcsp->rx_skb->data[bcsp->rx_skb->len - 2] << 8) +
					bcsp->rx_skb->data[bcsp->rx_skb->len - 1]) {

				BT_ERR ("Checksum failed: computed %04x received %04x",
					bcsp_crc_reverse(bcsp->message_crc),
				     	(bcsp->rx_skb-> data[bcsp->rx_skb->len - 2] << 8) +
				     	bcsp->rx_skb->data[bcsp->rx_skb->len - 1]);

				kfree_skb(bcsp->rx_skb);
				bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
				bcsp->rx_count = 0;
				continue;
			}
			skb_trim(bcsp->rx_skb, bcsp->rx_skb->len - 2);
			bcsp_complete_rx_pkt(hu);
			continue;

		case BCSP_W4_PKT_DELIMITER:
			switch (*ptr) {
			case 0xc0:
				bcsp->rx_state = BCSP_W4_PKT_START;
				break;
			default:
				/*BT_ERR("Ignoring byte %02x", *ptr);*/
				break;
			}
			ptr++; count--;
			break;

		case BCSP_W4_PKT_START:
			switch (*ptr) {
			case 0xc0:
				ptr++; count--;
				break;

			default:
				bcsp->rx_state = BCSP_W4_BCSP_HDR;
				bcsp->rx_count = 4;
				bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
				BCSP_CRC_INIT(bcsp->message_crc);
				
				/* Do not increment ptr or decrement count
				 * Allocate packet. Max len of a BCSP pkt= 
				 * 0xFFF (payload) +4 (header) +2 (crc) */

				bcsp->rx_skb = bt_skb_alloc(0x1005, GFP_ATOMIC);
				if (!bcsp->rx_skb) {
					BT_ERR("Can't allocate mem for new packet");
					bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
					bcsp->rx_count = 0;
					return 0;
				}
				bcsp->rx_skb->dev = (void *) hu->hdev;
				break;
			}
			break;
		}
	}
	return count;
}

	/* Arrange to retransmit all messages in the relq. */
static void bcsp_timed_event(unsigned long arg)
{
	struct hci_uart *hu = (struct hci_uart *) arg;
	struct bcsp_struct *bcsp = hu->priv;
	struct sk_buff *skb;
	unsigned long flags;

	BT_DBG("hu %p retransmitting %u pkts", hu, bcsp->unack.qlen);

	spin_lock_irqsave(&bcsp->unack.lock, flags);

	while ((skb = __skb_dequeue_tail(&bcsp->unack)) != NULL) {
		bcsp->msgq_txseq = (bcsp->msgq_txseq - 1) & 0x07;
		skb_queue_head(&bcsp->rel, skb);
	}

	spin_unlock_irqrestore(&bcsp->unack.lock, flags);

	hci_uart_tx_wakeup(hu);
}

static int bcsp_open(struct hci_uart *hu)
{
	struct bcsp_struct *bcsp;

	BT_DBG("hu %p", hu);

	bcsp = kmalloc(sizeof(*bcsp), GFP_ATOMIC);
	if (!bcsp)
		return -ENOMEM;
	memset(bcsp, 0, sizeof(*bcsp));

	hu->priv = bcsp;
	skb_queue_head_init(&bcsp->unack);
	skb_queue_head_init(&bcsp->rel);
	skb_queue_head_init(&bcsp->unrel);

	init_timer(&bcsp->tbcsp);
	bcsp->tbcsp.function = bcsp_timed_event;
	bcsp->tbcsp.data     = (u_long) hu;

	bcsp->rx_state = BCSP_W4_PKT_DELIMITER;

	if (txcrc)
		bcsp->use_crc = 1;

	return 0;
}

static int bcsp_close(struct hci_uart *hu)
{
	struct bcsp_struct *bcsp = hu->priv;
	hu->priv = NULL;

	BT_DBG("hu %p", hu);

	skb_queue_purge(&bcsp->unack);
	skb_queue_purge(&bcsp->rel);
	skb_queue_purge(&bcsp->unrel);
	del_timer(&bcsp->tbcsp);

	kfree(bcsp);
	return 0;
}

static struct hci_uart_proto bcsp = {
	.id      = HCI_UART_BCSP,
	.open    = bcsp_open,
	.close   = bcsp_close,
	.enqueue = bcsp_enqueue,
	.dequeue = bcsp_dequeue,
	.recv    = bcsp_recv,
	.flush   = bcsp_flush
};

int bcsp_init(void)
{
	int err = hci_uart_register_proto(&bcsp);
	if (!err)
		BT_INFO("HCI BCSP protocol initialized");
	else
		BT_ERR("HCI BCSP protocol registration failed");

	return err;
}

int bcsp_deinit(void)
{
	return hci_uart_unregister_proto(&bcsp);
}

module_param(txcrc, bool, 0644);
MODULE_PARM_DESC(txcrc, "Transmit CRC with every BCSP packet");

module_param(hciextn, bool, 0644);
MODULE_PARM_DESC(hciextn, "Convert HCI Extensions into BCSP packets");