[deliverable/linux.git] / drivers / bluetooth / hci_h5.c

/*
 *
 *  Bluetooth HCI Three-wire UART driver
 *
 *  Copyright (C) 2012  Intel Corporation
 *
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/skbuff.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>

#include "hci_uart.h"

#define HCI_3WIRE_ACK_PKT	0
#define HCI_3WIRE_LINK_PKT	15

#define H5_TXWINSIZE	4

#define H5_ACK_TIMEOUT	msecs_to_jiffies(250)
#define H5_SYNC_TIMEOUT	msecs_to_jiffies(100)

/*
 * Maximum Three-wire packet:
 *     4 byte header + max value for 12-bit length + 2 bytes for CRC
 */
#define H5_MAX_LEN (4 + 0xfff + 2)

/* Convenience macros for reading Three-wire header values */
#define H5_HDR_SEQ(hdr)		((hdr)[0] & 0x07)
#define H5_HDR_ACK(hdr)		(((hdr)[0] >> 3) & 0x07)
#define H5_HDR_CRC(hdr)		(((hdr)[0] >> 6) & 0x01)
#define H5_HDR_RELIABLE(hdr)	(((hdr)[0] >> 7) & 0x01)
#define H5_HDR_PKT_TYPE(hdr)	((hdr)[1] & 0x0f)
#define H5_HDR_LEN(hdr)		((((hdr)[1] >> 4) & 0xff) + ((hdr)[2] << 4))

#define SLIP_DELIMITER	0xc0
#define SLIP_ESC	0xdb
#define SLIP_ESC_DELIM	0xdc
#define SLIP_ESC_ESC	0xdd

struct h5 {
	struct sk_buff_head	unack;		/* Unack'ed packets queue */
	struct sk_buff_head	rel;		/* Reliable packets queue */
	struct sk_buff_head	unrel;		/* Unreliable packets queue */

	struct sk_buff		*rx_skb;	/* Receive buffer */
	size_t			rx_pending;	/* Expecting more bytes */
	bool			rx_esc;		/* SLIP escape mode */
	u8			rx_ack;		/* Last ack number received */

	int			(*rx_func) (struct hci_uart *hu, u8 c);

	struct timer_list	timer;		/* Retransmission timer */

	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);

static void h5_timed_event(unsigned long arg)
{
	struct hci_uart *hu = (struct hci_uart *) arg;
	struct h5 *h5 = hu->priv;
	struct sk_buff *skb;
	unsigned long flags;

	BT_DBG("hu %p retransmitting %u pkts", hu, h5->unack.qlen);

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

	while ((skb = __skb_dequeue_tail(&h5->unack)) != NULL) {
		h5->tx_seq = (h5->tx_seq - 1) & 0x07;
		skb_queue_head(&h5->rel, skb);
	}

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

	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);

	h5 = kzalloc(sizeof(*h5), GFP_KERNEL);
	if (!h5)
		return -ENOMEM;

	hu->priv = h5;

	skb_queue_head_init(&h5->unack);
	skb_queue_head_init(&h5->rel);
	skb_queue_head_init(&h5->unrel);

	h5_reset_rx(h5);

	init_timer(&h5->timer);
	h5->timer.function = h5_timed_event;
	h5->timer.data = (unsigned long) hu;

	set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags);

	/* Send initial sync request */
	h5_link_control(hu, sync, sizeof(sync));
	mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);

	return 0;
}

static int h5_close(struct hci_uart *hu)
{
	struct h5 *h5 = hu->priv;

	skb_queue_purge(&h5->unack);
	skb_queue_purge(&h5->rel);
	skb_queue_purge(&h5->unrel);

	del_timer(&h5->timer);

	kfree(h5);

	return 0;
}

static void h5_pkt_cull(struct h5 *h5)
{
	struct sk_buff *skb, *tmp;
	unsigned long flags;
	int i, to_remove;
	u8 seq;

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

	to_remove = skb_queue_len(&h5->unack);
	if (to_remove == 0)
		goto unlock;

	seq = h5->tx_seq;

	while (to_remove > 0) {
		if (h5->rx_ack == seq)
			break;

		to_remove--;
		seq = (seq - 1) % 8;
	}

	if (seq != h5->rx_ack)
		BT_ERR("Controller acked invalid packet");

	i = 0;
	skb_queue_walk_safe(&h5->unack, skb, tmp) {
		if (i++ >= to_remove)
			break;

		__skb_unlink(skb, &h5->unack);
		kfree_skb(skb);
	}

	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");
		hci_uart_init_ready(hu);
		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)
{
	struct h5 *h5 = hu->priv;
	const unsigned char *hdr = h5->rx_skb->data;

	if (H5_HDR_RELIABLE(hdr)) {
		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);

	h5_pkt_cull(h5);

	switch (H5_HDR_PKT_TYPE(hdr)) {
	case HCI_EVENT_PKT:
	case HCI_ACLDATA_PKT:
	case HCI_SCODATA_PKT:
		bt_cb(h5->rx_skb)->pkt_type = H5_HDR_PKT_TYPE(hdr);

		/* Remove Three-wire header */
		skb_pull(h5->rx_skb, 4);

		hci_recv_frame(h5->rx_skb);
		h5->rx_skb = NULL;

		break;

	default:
		h5_handle_internal_rx(hu);
		break;
	}

	h5_reset_rx(h5);
}

static int h5_rx_crc(struct hci_uart *hu, unsigned char c)
{
	struct h5 *h5 = hu->priv;

	h5_complete_rx_pkt(hu);
	h5_reset_rx(h5);

	return 0;
}

static int h5_rx_payload(struct hci_uart *hu, unsigned char c)
{
	struct h5 *h5 = hu->priv;
	const unsigned char *hdr = h5->rx_skb->data;

	if (H5_HDR_CRC(hdr)) {
		h5->rx_func = h5_rx_crc;
		h5->rx_pending = 2;
	} else {
		h5_complete_rx_pkt(hu);
		h5_reset_rx(h5);
	}

	return 0;
}

static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c)
{
	struct h5 *h5 = hu->priv;
	const unsigned char *hdr = h5->rx_skb->data;

	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_ack) {
		BT_ERR("Out-of-order packet arrived (%u != %u)",
		       H5_HDR_SEQ(hdr), h5->tx_ack);
		h5_reset_rx(h5);
		return 0;
	}

	h5->rx_func = h5_rx_payload;
	h5->rx_pending = H5_HDR_LEN(hdr);

	return 0;
}

static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c)
{
	struct h5 *h5 = hu->priv;

	if (c == SLIP_DELIMITER)
		return 1;

	h5->rx_func = h5_rx_3wire_hdr;
	h5->rx_pending = 4;

	h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC);
	if (!h5->rx_skb) {
		BT_ERR("Can't allocate mem for new packet");
		h5_reset_rx(h5);
		return -ENOMEM;
	}

	h5->rx_skb->dev = (void *) hu->hdev;

	return 0;
}

static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c)
{
	struct h5 *h5 = hu->priv;

	if (c == SLIP_DELIMITER)
		h5->rx_func = h5_rx_pkt_start;

	return 1;
}

static void h5_unslip_one_byte(struct h5 *h5, unsigned char c)
{
	const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC;
	const u8 *byte = &c;

	if (!h5->rx_esc && c == SLIP_ESC) {
		h5->rx_esc = true;
		return;
	}

	if (h5->rx_esc) {
		switch (c) {
		case SLIP_ESC_DELIM:
			byte = &delim;
			break;
		case SLIP_ESC_ESC:
			byte = &esc;
			break;
		default:
			BT_ERR("Invalid esc byte 0x%02hhx", c);
			h5_reset_rx(h5);
			return;
		}

		h5->rx_esc = false;
	}

	memcpy(skb_put(h5->rx_skb, 1), byte, 1);
	h5->rx_pending--;

	BT_DBG("unsliped 0x%02hhx, rx_pending %zu", *byte, h5->rx_pending);
}

static void h5_reset_rx(struct h5 *h5)
{
	if (h5->rx_skb) {
		kfree_skb(h5->rx_skb);
		h5->rx_skb = NULL;
	}

	h5->rx_func = h5_rx_delimiter;
	h5->rx_pending = 0;
	h5->rx_esc = false;
}

static int h5_recv(struct hci_uart *hu, void *data, int count)
{
	struct h5 *h5 = hu->priv;
	unsigned char *ptr = data;

	BT_DBG("%s pending %zu count %d", hu->hdev->name, h5->rx_pending,
	       count);

	while (count > 0) {
		int processed;

		if (h5->rx_pending > 0) {
			if (*ptr == SLIP_DELIMITER) {
				BT_ERR("Too short H5 packet");
				h5_reset_rx(h5);
				continue;
			}

			h5_unslip_one_byte(h5, *ptr);

			ptr++; count--;
			continue;
		}

		processed = h5->rx_func(hu, *ptr);
		if (processed < 0)
			return processed;

		ptr += processed;
		count -= processed;
	}

	return 0;
}

static int h5_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
	struct h5 *h5 = hu->priv;

	if (skb->len > 0xfff) {
		BT_ERR("Packet too long (%u bytes)", skb->len);
		kfree_skb(skb);
		return 0;
	}

	switch (bt_cb(skb)->pkt_type) {
	case HCI_ACLDATA_PKT:
	case HCI_COMMAND_PKT:
		skb_queue_tail(&h5->rel, skb);
		break;

	case HCI_SCODATA_PKT:
		skb_queue_tail(&h5->unrel, skb);
		break;

	default:
		BT_ERR("Unknown packet type %u", bt_cb(skb)->pkt_type);
		kfree_skb(skb);
		break;
	}

	return 0;
}

static void h5_slip_delim(struct sk_buff *skb)
{
	const char delim = SLIP_DELIMITER;

	memcpy(skb_put(skb, 1), &delim, 1);
}

static void h5_slip_one_byte(struct sk_buff *skb, u8 c)
{
	const char esc_delim[2] = { SLIP_ESC, SLIP_ESC_DELIM };
	const char esc_esc[2] = { SLIP_ESC, SLIP_ESC_ESC };

	switch (c) {
	case SLIP_DELIMITER:
		memcpy(skb_put(skb, 2), &esc_delim, 2);
		break;
	case SLIP_ESC:
		memcpy(skb_put(skb, 2), &esc_esc, 2);
		break;
	default:
		memcpy(skb_put(skb, 1), &c, 1);
	}
}

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;

	/*
	 * Max len of packet: (original len + 4 (H5 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;

	h5_slip_delim(nskb);

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

	if (rel) {
		hdr[0] |= 1 << 7;
		hdr[0] |= h5->tx_seq;
		h5->tx_seq = (h5->tx_seq + 1) % 8;
	}

	hdr[1] = pkt_type | ((len & 0x0f) << 4);
	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]);

	for (i = 0; i < len; i++)
		h5_slip_one_byte(nskb, data[i]);

	h5_slip_delim(nskb);

	return nskb;
}

static struct sk_buff *h5_prepare_pkt(struct hci_uart *hu, u8 pkt_type,
				      const u8 *data, size_t len)
{
	bool rel;

	switch (pkt_type) {
	case HCI_ACLDATA_PKT:
	case HCI_COMMAND_PKT:
		rel = true;
		break;
	case HCI_SCODATA_PKT:
	case HCI_3WIRE_LINK_PKT:
	case HCI_3WIRE_ACK_PKT:
		rel = false;
		break;
	default:
		BT_ERR("Unknown packet type %u", pkt_type);
		return NULL;
	}

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

static struct sk_buff *h5_dequeue(struct hci_uart *hu)
{
	struct h5 *h5 = hu->priv;
	unsigned long flags;
	struct sk_buff *skb, *nskb;

	if ((skb = skb_dequeue(&h5->unrel)) != NULL) {
		nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
				      skb->data, skb->len);
		if (nskb) {
			kfree_skb(skb);
			return nskb;
		}

		skb_queue_head(&h5->unrel, skb);
		BT_ERR("Could not dequeue pkt because alloc_skb failed");
	}

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

	if (h5->unack.qlen >= H5_TXWINSIZE)
		goto unlock;

	if ((skb = skb_dequeue(&h5->rel)) != NULL) {
		nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
				      skb->data, skb->len);
		if (nskb) {
			__skb_queue_tail(&h5->unack, skb);
			mod_timer(&h5->timer, jiffies + H5_ACK_TIMEOUT);
			spin_unlock_irqrestore(&h5->unack.lock, flags);
			return nskb;
		}

		skb_queue_head(&h5->rel, skb);
		BT_ERR("Could not dequeue pkt because alloc_skb failed");
	}

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

	if (h5->tx_ack_req)
		return h5_prepare_pkt(hu, HCI_3WIRE_ACK_PKT, NULL, 0);

	return NULL;
}

static int h5_flush(struct hci_uart *hu)
{
	BT_DBG("hu %p", hu);
	return 0;
}

static struct hci_uart_proto h5p = {
	.id		= HCI_UART_3WIRE,
	.open		= h5_open,
	.close		= h5_close,
	.recv		= h5_recv,
	.enqueue	= h5_enqueue,
	.dequeue	= h5_dequeue,
	.flush		= h5_flush,
};

int __init h5_init(void)
{
	int err = hci_uart_register_proto(&h5p);

	if (!err)
		BT_INFO("HCI Three-wire UART (H5) protocol initialized");
	else
		BT_ERR("HCI Three-wire UART (H5) protocol init failed");

	return err;
}

int __exit h5_deinit(void)
{
	return hci_uart_unregister_proto(&h5p);
}
Commit	Line	Data
7dec65c8 JH	1	/*
	2	*
	3	* Bluetooth HCI Three-wire UART driver
	4	*
	5	* Copyright (C) 2012 Intel Corporation
	6	*
	7	*
	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.
	12	*
	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.
	17	*
	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
	21	*
	22	*/
	23
	24	#include <linux/kernel.h>
	25	#include <linux/errno.h>
	26	#include <linux/skbuff.h>
	27
	28	#include <net/bluetooth/bluetooth.h>
	29	#include <net/bluetooth/hci_core.h>
	30
	31	#include "hci_uart.h"
	32
c0a1b73c JH	33	#define HCI_3WIRE_ACK_PKT 0
	34	#define HCI_3WIRE_LINK_PKT 15
	35
3f27e95b JH	36	#define H5_TXWINSIZE 4
	37
	38	#define H5_ACK_TIMEOUT msecs_to_jiffies(250)
40f10224	39	#define H5_SYNC_TIMEOUT msecs_to_jiffies(100)
3f27e95b	40
bc1f35b9 JH	41	/*
	42	* Maximum Three-wire packet:
	43	* 4 byte header + max value for 12-bit length + 2 bytes for CRC
	44	*/
	45	#define H5_MAX_LEN (4 + 0xfff + 2)
	46
01977c0b JH	47	/* Convenience macros for reading Three-wire header values */
	48	#define H5_HDR_SEQ(hdr) ((hdr)[0] & 0x07)
	49	#define H5_HDR_ACK(hdr) (((hdr)[0] >> 3) & 0x07)
	50	#define H5_HDR_CRC(hdr) (((hdr)[0] >> 6) & 0x01)
	51	#define H5_HDR_RELIABLE(hdr) (((hdr)[0] >> 7) & 0x01)
	52	#define H5_HDR_PKT_TYPE(hdr) ((hdr)[1] & 0x0f)
	53	#define H5_HDR_LEN(hdr) ((((hdr)[1] >> 4) & 0xff) + ((hdr)[2] << 4))
	54
bc1f35b9 JH	55	#define SLIP_DELIMITER 0xc0
	56	#define SLIP_ESC 0xdb
	57	#define SLIP_ESC_DELIM 0xdc
	58	#define SLIP_ESC_ESC 0xdd
	59
7d664fba	60	struct h5 {
bc1f35b9 JH	61	struct sk_buff_head unack; /* Unack'ed packets queue */
	62	struct sk_buff_head rel; /* Reliable packets queue */
	63	struct sk_buff_head unrel; /* Unreliable packets queue */
	64
	65	struct sk_buff rx_skb; / Receive buffer */
	66	size_t rx_pending; /* Expecting more bytes */
	67	bool rx_esc; /* SLIP escape mode */
43eb12d7	68	u8 rx_ack; /* Last ack number received */
7d664fba	69
bc1f35b9	70	int (rx_func) (struct hci_uart hu, u8 c);
7d664fba	71
bc1f35b9	72	struct timer_list timer; /* Retransmission timer */
3f27e95b	73
43eb12d7 JH	74	bool tx_ack_req; /* Pending ack to send */
43eb12d7 JH	75	u8 tx_seq; /* Next seq number to send */
40f10224	76	u8 tx_ack; /* Next ack number to send */
7d664fba JH	77	};
7d664fba JH	78
bc1f35b9 JH	79	static void h5_reset_rx(struct h5 *h5);
bc1f35b9 JH	80
3f27e95b JH	81	static void h5_timed_event(unsigned long arg)
	82	{
	83	struct hci_uart hu = (struct hci_uart ) arg;
	84	struct h5 *h5 = hu->priv;
	85	struct sk_buff *skb;
	86	unsigned long flags;
	87
	88	BT_DBG("hu %p retransmitting %u pkts", hu, h5->unack.qlen);
	89
	90	spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
	91
	92	while ((skb = __skb_dequeue_tail(&h5->unack)) != NULL) {
43eb12d7	93	h5->tx_seq = (h5->tx_seq - 1) & 0x07;
3f27e95b JH	94	skb_queue_head(&h5->rel, skb);
	95	}
	96
	97	spin_unlock_irqrestore(&h5->unack.lock, flags);
	98
	99	hci_uart_tx_wakeup(hu);
	100	}
	101
40f10224 JH	102	static void h5_link_control(struct hci_uart hu, const void data, size_t len)
	103	{
	104	struct h5 *h5 = hu->priv;
	105	struct sk_buff *nskb;
	106
	107	nskb = alloc_skb(3, GFP_ATOMIC);
	108	if (!nskb)
	109	return;
	110
	111	bt_cb(nskb)->pkt_type = HCI_3WIRE_LINK_PKT;
	112
	113	memcpy(skb_put(nskb, len), data, len);
	114
	115	skb_queue_tail(&h5->unrel, nskb);
	116	}
	117
7dec65c8 JH	118	static int h5_open(struct hci_uart *hu)
7dec65c8 JH	119	{
7d664fba	120	struct h5 *h5;
40f10224	121	const unsigned char sync[] = { 0x01, 0x7e };
7d664fba JH	122
	123	BT_DBG("hu %p", hu);
	124
	125	h5 = kzalloc(sizeof(*h5), GFP_KERNEL);
	126	if (!h5)
	127	return -ENOMEM;
	128
	129	hu->priv = h5;
	130
	131	skb_queue_head_init(&h5->unack);
	132	skb_queue_head_init(&h5->rel);
	133	skb_queue_head_init(&h5->unrel);
	134
bc1f35b9 JH	135	h5_reset_rx(h5);
bc1f35b9 JH	136
3f27e95b JH	137	init_timer(&h5->timer);
	138	h5->timer.function = h5_timed_event;
	139	h5->timer.data = (unsigned long) hu;
	140
cd1b4425 JH	141	set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags);
cd1b4425 JH	142
40f10224 JH	143	/* Send initial sync request */
	144	h5_link_control(hu, sync, sizeof(sync));
	145	mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
	146
7d664fba	147	return 0;
7dec65c8 JH	148	}
	149
	150	static int h5_close(struct hci_uart *hu)
	151	{
7d664fba JH	152	struct h5 *h5 = hu->priv;
	153
	154	skb_queue_purge(&h5->unack);
	155	skb_queue_purge(&h5->rel);
	156	skb_queue_purge(&h5->unrel);
	157
3f27e95b JH	158	del_timer(&h5->timer);
3f27e95b JH	159
7d664fba JH	160	kfree(h5);
	161
	162	return 0;
7dec65c8 JH	163	}
7dec65c8 JH	164
43eb12d7 JH	165	static void h5_pkt_cull(struct h5 *h5)
	166	{
	167	struct sk_buff skb, tmp;
	168	unsigned long flags;
	169	int i, to_remove;
	170	u8 seq;
	171
	172	spin_lock_irqsave(&h5->unack.lock, flags);
	173
	174	to_remove = skb_queue_len(&h5->unack);
40f10224 JH	175	if (to_remove == 0)
40f10224 JH	176	goto unlock;
43eb12d7 JH	177
	178	seq = h5->tx_seq;
	179
	180	while (to_remove > 0) {
	181	if (h5->rx_ack == seq)
	182	break;
	183
	184	to_remove--;
	185	seq = (seq - 1) % 8;
	186	}
	187
	188	if (seq != h5->rx_ack)
	189	BT_ERR("Controller acked invalid packet");
	190
	191	i = 0;
	192	skb_queue_walk_safe(&h5->unack, skb, tmp) {
	193	if (i++ >= to_remove)
	194	break;
	195
	196	__skb_unlink(skb, &h5->unack);
	197	kfree_skb(skb);
	198	}
	199
	200	if (skb_queue_empty(&h5->unack))
	201	del_timer(&h5->timer);
	202
40f10224	203	unlock:
43eb12d7 JH	204	spin_unlock_irqrestore(&h5->unack.lock, flags);
	205	}
	206
bc1f35b9 JH	207	static void h5_handle_internal_rx(struct hci_uart *hu)
bc1f35b9 JH	208	{
40f10224 JH	209	struct h5 *h5 = hu->priv;
	210	const unsigned char sync_req[] = { 0x01, 0x7e };
	211	const unsigned char sync_rsp[] = { 0x02, 0x7d };
	212	const unsigned char conf_req[] = { 0x03, 0xfc, 0x01 };
	213	const unsigned char conf_rsp[] = { 0x04, 0x7b, 0x01 };
	214	const unsigned char *hdr = h5->rx_skb->data;
	215	const unsigned char *data = &h5->rx_skb->data[4];
	216
bc1f35b9	217	BT_DBG("%s", hu->hdev->name);
40f10224 JH	218
	219	if (H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT)
	220	return;
	221
	222	if (H5_HDR_LEN(hdr) < 2)
	223	return;
	224
	225	if (memcmp(data, sync_req, 2) == 0) {
	226	h5_link_control(hu, sync_rsp, 2);
	227	} else if (memcmp(data, sync_rsp, 2) == 0) {
	228	h5_link_control(hu, conf_req, 3);
	229	} else if (memcmp(data, conf_req, 2) == 0) {
	230	h5_link_control(hu, conf_rsp, 2);
	231	h5_link_control(hu, conf_req, 3);
	232	} else if (memcmp(data, conf_rsp, 2) == 0) {
	233	BT_DBG("Three-wire init sequence complete");
cd1b4425	234	hci_uart_init_ready(hu);
40f10224 JH	235	return;
	236	} else {
	237	BT_DBG("Link Control: 0x%02hhx 0x%02hhx", data[0], data[1]);
	238	return;
	239	}
	240
	241	hci_uart_tx_wakeup(hu);
bc1f35b9 JH	242	}
	243
	244	static void h5_complete_rx_pkt(struct hci_uart *hu)
	245	{
	246	struct h5 *h5 = hu->priv;
43eb12d7	247	const unsigned char *hdr = h5->rx_skb->data;
bc1f35b9	248
43eb12d7	249	if (H5_HDR_RELIABLE(hdr)) {
40f10224	250	h5->tx_ack = (h5->tx_ack + 1) % 8;
43eb12d7	251	h5->tx_ack_req = true;
40f10224	252	hci_uart_tx_wakeup(hu);
43eb12d7	253	}
bc1f35b9	254
43eb12d7 JH	255	h5->rx_ack = H5_HDR_ACK(hdr);
	256
	257	h5_pkt_cull(h5);
	258
	259	switch (H5_HDR_PKT_TYPE(hdr)) {
bc1f35b9 JH	260	case HCI_EVENT_PKT:
	261	case HCI_ACLDATA_PKT:
	262	case HCI_SCODATA_PKT:
43eb12d7	263	bt_cb(h5->rx_skb)->pkt_type = H5_HDR_PKT_TYPE(hdr);
bc1f35b9 JH	264
	265	/* Remove Three-wire header */
	266	skb_pull(h5->rx_skb, 4);
	267
	268	hci_recv_frame(h5->rx_skb);
	269	h5->rx_skb = NULL;
	270
	271	break;
	272
	273	default:
	274	h5_handle_internal_rx(hu);
	275	break;
	276	}
	277
	278	h5_reset_rx(h5);
	279	}
	280
	281	static int h5_rx_crc(struct hci_uart *hu, unsigned char c)
	282	{
	283	struct h5 *h5 = hu->priv;
	284
bc1f35b9 JH	285	h5_complete_rx_pkt(hu);
	286	h5_reset_rx(h5);
	287
	288	return 0;
	289	}
	290
	291	static int h5_rx_payload(struct hci_uart *hu, unsigned char c)
	292	{
	293	struct h5 *h5 = hu->priv;
	294	const unsigned char *hdr = h5->rx_skb->data;
	295
43eb12d7	296	if (H5_HDR_CRC(hdr)) {
bc1f35b9 JH	297	h5->rx_func = h5_rx_crc;
	298	h5->rx_pending = 2;
	299	} else {
	300	h5_complete_rx_pkt(hu);
	301	h5_reset_rx(h5);
	302	}
	303
	304	return 0;
	305	}
	306
	307	static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c)
	308	{
	309	struct h5 *h5 = hu->priv;
	310	const unsigned char *hdr = h5->rx_skb->data;
	311
40f10224 JH	312	BT_DBG("%s rx: seq %u ack %u crc %u rel %u type %u len %u",
	313	hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
	314	H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
	315	H5_HDR_LEN(hdr));
	316
bc1f35b9 JH	317	if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) {
	318	BT_ERR("Invalid header checksum");
	319	h5_reset_rx(h5);
	320	return 0;
	321	}
	322
40f10224	323	if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_ack) {
43eb12d7	324	BT_ERR("Out-of-order packet arrived (%u != %u)",
40f10224	325	H5_HDR_SEQ(hdr), h5->tx_ack);
43eb12d7 JH	326	h5_reset_rx(h5);
	327	return 0;
	328	}
	329
bc1f35b9	330	h5->rx_func = h5_rx_payload;
43eb12d7	331	h5->rx_pending = H5_HDR_LEN(hdr);
bc1f35b9 JH	332
	333	return 0;
	334	}
	335
	336	static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c)
	337	{
	338	struct h5 *h5 = hu->priv;
	339
bc1f35b9 JH	340	if (c == SLIP_DELIMITER)
	341	return 1;
	342
	343	h5->rx_func = h5_rx_3wire_hdr;
	344	h5->rx_pending = 4;
	345
	346	h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC);
	347	if (!h5->rx_skb) {
	348	BT_ERR("Can't allocate mem for new packet");
	349	h5_reset_rx(h5);
	350	return -ENOMEM;
	351	}
	352
	353	h5->rx_skb->dev = (void *) hu->hdev;
	354
	355	return 0;
	356	}
	357
	358	static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c)
	359	{
	360	struct h5 *h5 = hu->priv;
	361
bc1f35b9 JH	362	if (c == SLIP_DELIMITER)
	363	h5->rx_func = h5_rx_pkt_start;
	364
	365	return 1;
	366	}
	367
	368	static void h5_unslip_one_byte(struct h5 *h5, unsigned char c)
	369	{
	370	const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC;
	371	const u8 *byte = &c;
	372
	373	if (!h5->rx_esc && c == SLIP_ESC) {
	374	h5->rx_esc = true;
	375	return;
	376	}
	377
	378	if (h5->rx_esc) {
	379	switch (c) {
	380	case SLIP_ESC_DELIM:
	381	byte = &delim;
	382	break;
	383	case SLIP_ESC_ESC:
	384	byte = &esc;
	385	break;
	386	default:
	387	BT_ERR("Invalid esc byte 0x%02hhx", c);
	388	h5_reset_rx(h5);
	389	return;
	390	}
	391
	392	h5->rx_esc = false;
	393	}
	394
	395	memcpy(skb_put(h5->rx_skb, 1), byte, 1);
	396	h5->rx_pending--;
	397
255a68e0	398	BT_DBG("unsliped 0x%02hhx, rx_pending %zu", *byte, h5->rx_pending);
bc1f35b9 JH	399	}
	400
	401	static void h5_reset_rx(struct h5 *h5)
	402	{
	403	if (h5->rx_skb) {
	404	kfree_skb(h5->rx_skb);
	405	h5->rx_skb = NULL;
	406	}
	407
	408	h5->rx_func = h5_rx_delimiter;
	409	h5->rx_pending = 0;
	410	h5->rx_esc = false;
	411	}
	412
7dec65c8 JH	413	static int h5_recv(struct hci_uart hu, void data, int count)
7dec65c8 JH	414	{
bc1f35b9 JH	415	struct h5 *h5 = hu->priv;
	416	unsigned char *ptr = data;
	417
255a68e0 JH	418	BT_DBG("%s pending %zu count %d", hu->hdev->name, h5->rx_pending,
255a68e0 JH	419	count);
bc1f35b9 JH	420
	421	while (count > 0) {
	422	int processed;
	423
	424	if (h5->rx_pending > 0) {
	425	if (*ptr == SLIP_DELIMITER) {
	426	BT_ERR("Too short H5 packet");
	427	h5_reset_rx(h5);
	428	continue;
	429	}
	430
	431	h5_unslip_one_byte(h5, *ptr);
	432
	433	ptr++; count--;
	434	continue;
	435	}
	436
	437	processed = h5->rx_func(hu, *ptr);
	438	if (processed < 0)
	439	return processed;
	440
	441	ptr += processed;
	442	count -= processed;
	443	}
	444
	445	return 0;
7dec65c8 JH	446	}
	447
	448	static int h5_enqueue(struct hci_uart hu, struct sk_buff skb)
	449	{
7d664fba JH	450	struct h5 *h5 = hu->priv;
	451
	452	if (skb->len > 0xfff) {
	453	BT_ERR("Packet too long (%u bytes)", skb->len);
	454	kfree_skb(skb);
	455	return 0;
	456	}
	457
	458	switch (bt_cb(skb)->pkt_type) {
	459	case HCI_ACLDATA_PKT:
	460	case HCI_COMMAND_PKT:
	461	skb_queue_tail(&h5->rel, skb);
	462	break;
	463
	464	case HCI_SCODATA_PKT:
	465	skb_queue_tail(&h5->unrel, skb);
	466	break;
	467
	468	default:
	469	BT_ERR("Unknown packet type %u", bt_cb(skb)->pkt_type);
	470	kfree_skb(skb);
	471	break;
	472	}
	473
	474	return 0;
	475	}
	476
c0a1b73c JH	477	static void h5_slip_delim(struct sk_buff *skb)
	478	{
	479	const char delim = SLIP_DELIMITER;
	480
	481	memcpy(skb_put(skb, 1), &delim, 1);
	482	}
	483
	484	static void h5_slip_one_byte(struct sk_buff *skb, u8 c)
	485	{
	486	const char esc_delim[2] = { SLIP_ESC, SLIP_ESC_DELIM };
	487	const char esc_esc[2] = { SLIP_ESC, SLIP_ESC_ESC };
	488
	489	switch (c) {
	490	case SLIP_DELIMITER:
	491	memcpy(skb_put(skb, 2), &esc_delim, 2);
	492	break;
	493	case SLIP_ESC:
	494	memcpy(skb_put(skb, 2), &esc_esc, 2);
	495	break;
	496	default:
	497	memcpy(skb_put(skb, 1), &c, 1);
	498	}
	499	}
	500
40f10224	501	static struct sk_buff h5_build_pkt(struct hci_uart hu, bool rel, u8 pkt_type,
c0a1b73c	502	const u8 *data, size_t len)
7d664fba	503	{
40f10224	504	struct h5 *h5 = hu->priv;
c0a1b73c JH	505	struct sk_buff *nskb;
	506	u8 hdr[4];
	507	int i;
	508
	509	/*
	510	* Max len of packet: (original len + 4 (H5 hdr) + 2 (crc)) * 2
	511	* (because bytes 0xc0 and 0xdb are escaped, worst case is when
	512	* the packet is all made of 0xc0 and 0xdb) + 2 (0xc0
	513	* delimiters at start and end).
	514	*/
	515	nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
	516	if (!nskb)
	517	return NULL;
	518
	519	bt_cb(nskb)->pkt_type = pkt_type;
	520
	521	h5_slip_delim(nskb);
	522
40f10224	523	hdr[0] = h5->tx_ack << 3;
43eb12d7	524	h5->tx_ack_req = false;
c0a1b73c JH	525
	526	if (rel) {
	527	hdr[0] \|= 1 << 7;
43eb12d7 JH	528	hdr[0] \|= h5->tx_seq;
43eb12d7 JH	529	h5->tx_seq = (h5->tx_seq + 1) % 8;
c0a1b73c JH	530	}
	531
	532	hdr[1] = pkt_type \| ((len & 0x0f) << 4);
	533	hdr[2] = len >> 4;
	534	hdr[3] = ~((hdr[0] + hdr[1] + hdr[2]) & 0xff);
	535
40f10224 JH	536	BT_DBG("%s tx: seq %u ack %u crc %u rel %u type %u len %u",
	537	hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
	538	H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
	539	H5_HDR_LEN(hdr));
	540
c0a1b73c JH	541	for (i = 0; i < 4; i++)
	542	h5_slip_one_byte(nskb, hdr[i]);
	543
	544	for (i = 0; i < len; i++)
	545	h5_slip_one_byte(nskb, data[i]);
	546
	547	h5_slip_delim(nskb);
	548
	549	return nskb;
	550	}
	551
40f10224	552	static struct sk_buff h5_prepare_pkt(struct hci_uart hu, u8 pkt_type,
c0a1b73c JH	553	const u8 *data, size_t len)
	554	{
	555	bool rel;
	556
	557	switch (pkt_type) {
	558	case HCI_ACLDATA_PKT:
	559	case HCI_COMMAND_PKT:
	560	rel = true;
	561	break;
	562	case HCI_SCODATA_PKT:
	563	case HCI_3WIRE_LINK_PKT:
	564	case HCI_3WIRE_ACK_PKT:
	565	rel = false;
	566	break;
	567	default:
	568	BT_ERR("Unknown packet type %u", pkt_type);
	569	return NULL;
	570	}
	571
40f10224	572	return h5_build_pkt(hu, rel, pkt_type, data, len);
7dec65c8 JH	573	}
	574
	575	static struct sk_buff h5_dequeue(struct hci_uart hu)
	576	{
7d664fba	577	struct h5 *h5 = hu->priv;
3f27e95b	578	unsigned long flags;
7d664fba JH	579	struct sk_buff skb, nskb;
	580
	581	if ((skb = skb_dequeue(&h5->unrel)) != NULL) {
40f10224	582	nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
c0a1b73c	583	skb->data, skb->len);
7d664fba JH	584	if (nskb) {
	585	kfree_skb(skb);
	586	return nskb;
	587	}
	588
	589	skb_queue_head(&h5->unrel, skb);
	590	BT_ERR("Could not dequeue pkt because alloc_skb failed");
	591	}
	592
3f27e95b JH	593	spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
	594
	595	if (h5->unack.qlen >= H5_TXWINSIZE)
	596	goto unlock;
	597
	598	if ((skb = skb_dequeue(&h5->rel)) != NULL) {
40f10224	599	nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
c0a1b73c	600	skb->data, skb->len);
3f27e95b JH	601	if (nskb) {
	602	__skb_queue_tail(&h5->unack, skb);
	603	mod_timer(&h5->timer, jiffies + H5_ACK_TIMEOUT);
	604	spin_unlock_irqrestore(&h5->unack.lock, flags);
	605	return nskb;
	606	}
	607
	608	skb_queue_head(&h5->rel, skb);
	609	BT_ERR("Could not dequeue pkt because alloc_skb failed");
	610	}
	611
	612	unlock:
	613	spin_unlock_irqrestore(&h5->unack.lock, flags);
	614
43eb12d7	615	if (h5->tx_ack_req)
40f10224	616	return h5_prepare_pkt(hu, HCI_3WIRE_ACK_PKT, NULL, 0);
7d664fba	617
7dec65c8 JH	618	return NULL;
	619	}
	620
	621	static int h5_flush(struct hci_uart *hu)
	622	{
7d664fba JH	623	BT_DBG("hu %p", hu);
7d664fba JH	624	return 0;
7dec65c8 JH	625	}
	626
	627	static struct hci_uart_proto h5p = {
	628	.id = HCI_UART_3WIRE,
	629	.open = h5_open,
	630	.close = h5_close,
	631	.recv = h5_recv,
	632	.enqueue = h5_enqueue,
	633	.dequeue = h5_dequeue,
	634	.flush = h5_flush,
	635	};
	636
	637	int __init h5_init(void)
	638	{
	639	int err = hci_uart_register_proto(&h5p);
	640
	641	if (!err)
	642	BT_INFO("HCI Three-wire UART (H5) protocol initialized");
	643	else
	644	BT_ERR("HCI Three-wire UART (H5) protocol init failed");
	645
	646	return err;
	647	}
	648
	649	int __exit h5_deinit(void)
	650	{
	651	return hci_uart_unregister_proto(&h5p);
	652	}