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Commit 40f10224 authored by Johan Hedberg's avatar Johan Hedberg Committed by Gustavo Padovan
Browse files

Bluetooth: Add support for Three-wire Link Control packets 



This patch adds basic support for parsing and sending Three-wire UART
Link Control packets.

Signed-off-by: default avatarJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: default avatarGustavo Padovan <gustavo.padovan@collabora.co.uk>
parent 43eb12d7

drivers/bluetooth/hci_h5.c

+79 −17
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ 
#define H5_TXWINSIZE	4



#define H5_ACK_TIMEOUT	msecs_to_jiffies(250)

#define H5_SYNC_TIMEOUT	msecs_to_jiffies(100)



/*

 * Maximum Three-wire packet:
@@ -65,7 +66,6 @@ struct h5 { 
	size_t			rx_pending;	/* Expecting more bytes */

	bool			rx_esc;		/* SLIP escape mode */

	u8			rx_ack;		/* Last ack number received */

	u8			rx_seq;		/* Last seq number received */



	int			(*rx_func) (struct hci_uart *hu, u8 c);
@@ -73,6 +73,7 @@ struct h5 { 


	bool			tx_ack_req;	/* Pending ack to send */

	u8			tx_seq;		/* Next seq number to send */

	u8			tx_ack;		/* Next ack number to send */

};



static void h5_reset_rx(struct h5 *h5);
@@ -98,9 +99,26 @@ static void h5_timed_event(unsigned long arg) 
	hci_uart_tx_wakeup(hu);

}



static void h5_link_control(struct hci_uart *hu, const void *data, size_t len)

{

	struct h5 *h5 = hu->priv;

	struct sk_buff *nskb;



	nskb = alloc_skb(3, GFP_ATOMIC);

	if (!nskb)

		return;



	bt_cb(nskb)->pkt_type = HCI_3WIRE_LINK_PKT;



	memcpy(skb_put(nskb, len), data, len);



	skb_queue_tail(&h5->unrel, nskb);

}



static int h5_open(struct hci_uart *hu)

{

	struct h5 *h5;

	const unsigned char sync[] = { 0x01, 0x7e };



	BT_DBG("hu %p", hu);
@@ -120,6 +138,10 @@ static int h5_open(struct hci_uart *hu) 
	h5->timer.function = h5_timed_event;

	h5->timer.data = (unsigned long) hu;



	/* Send initial sync request */

	h5_link_control(hu, sync, sizeof(sync));

	mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);



	return 0;

}
@@ -148,6 +170,8 @@ static void h5_pkt_cull(struct h5 *h5) 
	spin_lock_irqsave(&h5->unack.lock, flags);



	to_remove = skb_queue_len(&h5->unack);

	if (to_remove == 0)

		goto unlock;



	seq = h5->tx_seq;
@@ -174,12 +198,44 @@ static void h5_pkt_cull(struct h5 *h5) 
	if (skb_queue_empty(&h5->unack))

		del_timer(&h5->timer);



unlock:

	spin_unlock_irqrestore(&h5->unack.lock, flags);

}



static void h5_handle_internal_rx(struct hci_uart *hu)

{

	struct h5 *h5 = hu->priv;

	const unsigned char sync_req[] = { 0x01, 0x7e };

	const unsigned char sync_rsp[] = { 0x02, 0x7d };

	const unsigned char conf_req[] = { 0x03, 0xfc, 0x01 };

	const unsigned char conf_rsp[] = { 0x04, 0x7b, 0x01 };

	const unsigned char *hdr = h5->rx_skb->data;

	const unsigned char *data = &h5->rx_skb->data[4];



	BT_DBG("%s", hu->hdev->name);



	if (H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT)

		return;



	if (H5_HDR_LEN(hdr) < 2)

		return;



	if (memcmp(data, sync_req, 2) == 0) {

		h5_link_control(hu, sync_rsp, 2);

	} else if (memcmp(data, sync_rsp, 2) == 0) {

		h5_link_control(hu, conf_req, 3);

	} else if (memcmp(data, conf_req, 2) == 0) {

		h5_link_control(hu, conf_rsp, 2);

		h5_link_control(hu, conf_req, 3);

	} else if (memcmp(data, conf_rsp, 2) == 0) {

		BT_DBG("Three-wire init sequence complete");

		return;

	} else {

		BT_DBG("Link Control: 0x%02hhx 0x%02hhx", data[0], data[1]);

		return;

	}



	hci_uart_tx_wakeup(hu);

}



static void h5_complete_rx_pkt(struct hci_uart *hu)
@@ -190,8 +246,9 @@ static void h5_complete_rx_pkt(struct hci_uart *hu) 
	BT_DBG("%s", hu->hdev->name);



	if (H5_HDR_RELIABLE(hdr)) {

		h5->tx_seq = (h5->tx_seq + 1) % 8;

		h5->tx_ack = (h5->tx_ack + 1) % 8;

		h5->tx_ack_req = true;

		hci_uart_tx_wakeup(hu);

	}



	h5->rx_ack = H5_HDR_ACK(hdr);
@@ -257,15 +314,20 @@ static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c) 


	BT_DBG("%s 0x%02hhx", hu->hdev->name, c);



	BT_DBG("%s rx: seq %u ack %u crc %u rel %u type %u len %u",

	       hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),

	       H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),

	       H5_HDR_LEN(hdr));



	if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) {

		BT_ERR("Invalid header checksum");

		h5_reset_rx(h5);

		return 0;

	}



	if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_seq) {

	if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_ack) {

		BT_ERR("Out-of-order packet arrived (%u != %u)",

		       H5_HDR_SEQ(hdr), h5->tx_seq);

		       H5_HDR_SEQ(hdr), h5->tx_ack);

		h5_reset_rx(h5);

		return 0;

	}
@@ -444,9 +506,10 @@ static void h5_slip_one_byte(struct sk_buff *skb, u8 c) 
	}

}



static struct sk_buff *h5_build_pkt(struct h5 *h5, bool rel, u8 pkt_type,

static struct sk_buff *h5_build_pkt(struct hci_uart *hu, bool rel, u8 pkt_type,

				    const u8 *data, size_t len)

{

	struct h5 *h5 = hu->priv;

	struct sk_buff *nskb;

	u8 hdr[4];

	int i;
@@ -465,7 +528,7 @@ static struct sk_buff *h5_build_pkt(struct h5 *h5, bool rel, u8 pkt_type, 


	h5_slip_delim(nskb);



	hdr[0] = h5->rx_seq << 3;

	hdr[0] = h5->tx_ack << 3;

	h5->tx_ack_req = false;



	if (rel) {
@@ -478,6 +541,11 @@ static struct sk_buff *h5_build_pkt(struct h5 *h5, bool rel, u8 pkt_type, 
	hdr[2] = len >> 4;

	hdr[3] = ~((hdr[0] + hdr[1] + hdr[2]) & 0xff);



	BT_DBG("%s tx: seq %u ack %u crc %u rel %u type %u len %u",

	       hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),

	       H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),

	       H5_HDR_LEN(hdr));



	for (i = 0; i < 4; i++)

		h5_slip_one_byte(nskb, hdr[i]);
@@ -489,7 +557,7 @@ static struct sk_buff *h5_build_pkt(struct h5 *h5, bool rel, u8 pkt_type, 
	return nskb;

}



static struct sk_buff *h5_prepare_pkt(struct h5 *h5, u8 pkt_type,

static struct sk_buff *h5_prepare_pkt(struct hci_uart *hu, u8 pkt_type,

				      const u8 *data, size_t len)

{

	bool rel;
@@ -509,13 +577,7 @@ static struct sk_buff *h5_prepare_pkt(struct h5 *h5, u8 pkt_type, 
		return NULL;

	}



	return h5_build_pkt(h5, rel, pkt_type, data, len);

}



static struct sk_buff *h5_prepare_ack(struct h5 *h5)

{

	h5->tx_ack_req = false;

	return NULL;

	return h5_build_pkt(hu, rel, pkt_type, data, len);

}



static struct sk_buff *h5_dequeue(struct hci_uart *hu)
@@ -525,7 +587,7 @@ static struct sk_buff *h5_dequeue(struct hci_uart *hu) 
	struct sk_buff *skb, *nskb;



	if ((skb = skb_dequeue(&h5->unrel)) != NULL) {

		nskb = h5_prepare_pkt(h5, bt_cb(skb)->pkt_type,

		nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,

				      skb->data, skb->len);

		if (nskb) {

			kfree_skb(skb);
@@ -542,7 +604,7 @@ static struct sk_buff *h5_dequeue(struct hci_uart *hu) 
		goto unlock;



	if ((skb = skb_dequeue(&h5->rel)) != NULL) {

		nskb = h5_prepare_pkt(h5, bt_cb(skb)->pkt_type,

		nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,

				      skb->data, skb->len);

		if (nskb) {

			__skb_queue_tail(&h5->unack, skb);
@@ -559,7 +621,7 @@ static struct sk_buff *h5_dequeue(struct hci_uart *hu) 
	spin_unlock_irqrestore(&h5->unack.lock, flags);



	if (h5->tx_ack_req)

		return h5_prepare_ack(h5);

		return h5_prepare_pkt(hu, HCI_3WIRE_ACK_PKT, NULL, 0);



	return NULL;

}