[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

/* Sliding window size */
#define H5_TX_WIN_MAX		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

/* H5 state flags */
enum {
	H5_RX_ESC,	/* SLIP escape mode */
	H5_TX_ACK_REQ,	/* Pending ack to send */
};

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 */

	unsigned long		flags;

	struct sk_buff		*rx_skb;	/* Receive buffer */
	size_t			rx_pending;	/* Expecting more bytes */
	u8			rx_ack;		/* Last ack number received */

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

	struct timer_list	timer;		/* Retransmission timer */

	u8			tx_seq;		/* Next seq number to send */
	u8			tx_ack;		/* Next ack number to send */
	u8			tx_win;		/* Sliding window size */

	enum {
		H5_UNINITIALIZED,
		H5_INITIALIZED,
		H5_ACTIVE,
	} state;

	enum {
		H5_AWAKE,
		H5_SLEEPING,
		H5_WAKING_UP,
	} sleep;
};

static void h5_reset_rx(struct h5 *h5);

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 u8 h5_cfg_field(struct h5 *h5)
{
	u8 field = 0;

	/* Sliding window size (first 3 bits) */
	field |= (h5->tx_win & 7);

	return field;
}

static void h5_timed_event(unsigned long arg)
{
	const unsigned char sync_req[] = { 0x01, 0x7e };
	unsigned char conf_req[] = { 0x03, 0xfc, 0x01 };
	struct hci_uart *hu = (struct hci_uart *) arg;
	struct h5 *h5 = hu->priv;
	struct sk_buff *skb;
	unsigned long flags;

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

	if (h5->state == H5_UNINITIALIZED)
		h5_link_control(hu, sync_req, sizeof(sync_req));

	if (h5->state == H5_INITIALIZED) {
		conf_req[2] = h5_cfg_field(h5);
		h5_link_control(hu, conf_req, sizeof(conf_req));
	}

	if (h5->state != H5_ACTIVE) {
		mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
		goto wakeup;
	}

	if (h5->sleep != H5_AWAKE) {
		h5->sleep = H5_SLEEPING;
		goto wakeup;
	}

	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);

wakeup:
	hci_uart_tx_wakeup(hu);
}

static void h5_peer_reset(struct hci_uart *hu)
{
	struct h5 *h5 = hu->priv;

	BT_ERR("Peer device has reset");

	h5->state = H5_UNINITIALIZED;

	del_timer(&h5->timer);

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

	h5->tx_seq = 0;
	h5->tx_ack = 0;

	/* Send reset request to upper stack */
	hci_reset_dev(hu->hdev);
}

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;

	h5->tx_win = H5_TX_WIN_MAX;

	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;

	del_timer_sync(&h5->timer);

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

	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) & 0x07;
	}

	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 };
	unsigned char conf_req[] = { 0x03, 0xfc, 0x01 };
	const unsigned char conf_rsp[] = { 0x04, 0x7b };
	const unsigned char wakeup_req[] = { 0x05, 0xfa };
	const unsigned char woken_req[] = { 0x06, 0xf9 };
	const unsigned char sleep_req[] = { 0x07, 0x78 };
	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;

	conf_req[2] = h5_cfg_field(h5);

	if (memcmp(data, sync_req, 2) == 0) {
		if (h5->state == H5_ACTIVE)
			h5_peer_reset(hu);
		h5_link_control(hu, sync_rsp, 2);
	} else if (memcmp(data, sync_rsp, 2) == 0) {
		if (h5->state == H5_ACTIVE)
			h5_peer_reset(hu);
		h5->state = H5_INITIALIZED;
		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) {
		if (H5_HDR_LEN(hdr) > 2)
			h5->tx_win = (data[2] & 7);
		BT_DBG("Three-wire init complete. tx_win %u", h5->tx_win);
		h5->state = H5_ACTIVE;
		hci_uart_init_ready(hu);
		return;
	} else if (memcmp(data, sleep_req, 2) == 0) {
		BT_DBG("Peer went to sleep");
		h5->sleep = H5_SLEEPING;
		return;
	} else if (memcmp(data, woken_req, 2) == 0) {
		BT_DBG("Peer woke up");
		h5->sleep = H5_AWAKE;
	} else if (memcmp(data, wakeup_req, 2) == 0) {
		BT_DBG("Peer requested wakeup");
		h5_link_control(hu, woken_req, 2);
		h5->sleep = H5_AWAKE;
	} 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;
		set_bit(H5_TX_ACK_REQ, &h5->flags);
		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(hu->hdev, 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)
{
	h5_complete_rx_pkt(hu);

	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);
	}

	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;
	}

	if (h5->state != H5_ACTIVE &&
	    H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT) {
		BT_ERR("Non-link packet received in non-active state");
		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 (!test_bit(H5_RX_ESC, &h5->flags) && c == SLIP_ESC) {
		set_bit(H5_RX_ESC, &h5->flags);
		return;
	}

	if (test_and_clear_bit(H5_RX_ESC, &h5->flags)) {
		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;
		}
	}

	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;
	clear_bit(H5_RX_ESC, &h5->flags);
}

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;
	}

	if (h5->state != H5_ACTIVE) {
		BT_ERR("Ignoring HCI data in non-active state");
		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 bool valid_packet_type(u8 type)
{
	switch (type) {
	case HCI_ACLDATA_PKT:
	case HCI_COMMAND_PKT:
	case HCI_SCODATA_PKT:
	case HCI_3WIRE_LINK_PKT:
	case HCI_3WIRE_ACK_PKT:
		return true;
	default:
		return false;
	}
}

static struct sk_buff *h5_prepare_pkt(struct hci_uart *hu, u8 pkt_type,
				      const u8 *data, size_t len)
{
	struct h5 *h5 = hu->priv;
	struct sk_buff *nskb;
	u8 hdr[4];
	int i;

	if (!valid_packet_type(pkt_type)) {
		BT_ERR("Unknown packet type %u", pkt_type);
		return NULL;
	}

	/*
	 * 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;
	clear_bit(H5_TX_ACK_REQ, &h5->flags);

	/* Reliable packet? */
	if (pkt_type == HCI_ACLDATA_PKT || pkt_type == HCI_COMMAND_PKT) {
		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_dequeue(struct hci_uart *hu)
{
	struct h5 *h5 = hu->priv;
	unsigned long flags;
	struct sk_buff *skb, *nskb;

	if (h5->sleep != H5_AWAKE) {
		const unsigned char wakeup_req[] = { 0x05, 0xfa };

		if (h5->sleep == H5_WAKING_UP)
			return NULL;

		h5->sleep = H5_WAKING_UP;
		BT_DBG("Sending wakeup request");

		mod_timer(&h5->timer, jiffies + HZ / 100);
		return h5_prepare_pkt(hu, HCI_3WIRE_LINK_PKT, wakeup_req, 2);
	}

	skb = skb_dequeue(&h5->unrel);
	if (skb != 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->tx_win)
		goto unlock;

	skb = skb_dequeue(&h5->rel);
	if (skb != 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 (test_bit(H5_TX_ACK_REQ, &h5->flags))
		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
afdc944c JH	36	/* Sliding window size */
afdc944c JH	37	#define H5_TX_WIN_MAX 4
3f27e95b JH	38
3f27e95b JH	39	#define H5_ACK_TIMEOUT msecs_to_jiffies(250)
40f10224	40	#define H5_SYNC_TIMEOUT msecs_to_jiffies(100)
3f27e95b	41
bc1f35b9 JH	42	/*
	43	* Maximum Three-wire packet:
	44	* 4 byte header + max value for 12-bit length + 2 bytes for CRC
	45	*/
	46	#define H5_MAX_LEN (4 + 0xfff + 2)
	47
01977c0b JH	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))
	55
bc1f35b9 JH	56	#define SLIP_DELIMITER 0xc0
	57	#define SLIP_ESC 0xdb
	58	#define SLIP_ESC_DELIM 0xdc
	59	#define SLIP_ESC_ESC 0xdd
	60
e0482103 JH	61	/* H5 state flags */
	62	enum {
	63	H5_RX_ESC, /* SLIP escape mode */
	64	H5_TX_ACK_REQ, /* Pending ack to send */
	65	};
	66
7d664fba	67	struct h5 {
bc1f35b9 JH	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 */
	71
e0482103 JH	72	unsigned long flags;
e0482103 JH	73
bc1f35b9 JH	74	struct sk_buff rx_skb; / Receive buffer */
bc1f35b9 JH	75	size_t rx_pending; /* Expecting more bytes */
43eb12d7	76	u8 rx_ack; /* Last ack number received */
7d664fba	77
bc1f35b9	78	int (rx_func) (struct hci_uart hu, u8 c);
7d664fba	79
bc1f35b9	80	struct timer_list timer; /* Retransmission timer */
3f27e95b	81
43eb12d7	82	u8 tx_seq; /* Next seq number to send */
40f10224	83	u8 tx_ack; /* Next ack number to send */
afdc944c	84	u8 tx_win; /* Sliding window size */
10122d07	85
f674a057 JH	86	enum {
	87	H5_UNINITIALIZED,
	88	H5_INITIALIZED,
	89	H5_ACTIVE,
	90	} state;
	91
95c5c220 JH	92	enum {
	93	H5_AWAKE,
	94	H5_SLEEPING,
	95	H5_WAKING_UP,
	96	} sleep;
7d664fba JH	97	};
7d664fba JH	98
bc1f35b9 JH	99	static void h5_reset_rx(struct h5 *h5);
bc1f35b9 JH	100
f674a057 JH	101	static void h5_link_control(struct hci_uart hu, const void data, size_t len)
	102	{
	103	struct h5 *h5 = hu->priv;
	104	struct sk_buff *nskb;
	105
	106	nskb = alloc_skb(3, GFP_ATOMIC);
	107	if (!nskb)
	108	return;
	109
	110	bt_cb(nskb)->pkt_type = HCI_3WIRE_LINK_PKT;
	111
	112	memcpy(skb_put(nskb, len), data, len);
	113
	114	skb_queue_tail(&h5->unrel, nskb);
	115	}
	116
afdc944c JH	117	static u8 h5_cfg_field(struct h5 *h5)
	118	{
	119	u8 field = 0;
	120
	121	/* Sliding window size (first 3 bits) */
	122	field \|= (h5->tx_win & 7);
	123
	124	return field;
	125	}
	126
3f27e95b JH	127	static void h5_timed_event(unsigned long arg)
3f27e95b JH	128	{
f674a057	129	const unsigned char sync_req[] = { 0x01, 0x7e };
afdc944c	130	unsigned char conf_req[] = { 0x03, 0xfc, 0x01 };
3f27e95b JH	131	struct hci_uart hu = (struct hci_uart ) arg;
	132	struct h5 *h5 = hu->priv;
	133	struct sk_buff *skb;
	134	unsigned long flags;
	135
95c5c220 JH	136	BT_DBG("%s", hu->hdev->name);
95c5c220 JH	137
f674a057 JH	138	if (h5->state == H5_UNINITIALIZED)
	139	h5_link_control(hu, sync_req, sizeof(sync_req));
	140
afdc944c JH	141	if (h5->state == H5_INITIALIZED) {
afdc944c JH	142	conf_req[2] = h5_cfg_field(h5);
f674a057	143	h5_link_control(hu, conf_req, sizeof(conf_req));
afdc944c	144	}
f674a057 JH	145
	146	if (h5->state != H5_ACTIVE) {
	147	mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
	148	goto wakeup;
	149	}
	150
95c5c220 JH	151	if (h5->sleep != H5_AWAKE) {
	152	h5->sleep = H5_SLEEPING;
	153	goto wakeup;
	154	}
	155
3f27e95b JH	156	BT_DBG("hu %p retransmitting %u pkts", hu, h5->unack.qlen);
	157
	158	spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
	159
	160	while ((skb = __skb_dequeue_tail(&h5->unack)) != NULL) {
43eb12d7	161	h5->tx_seq = (h5->tx_seq - 1) & 0x07;
3f27e95b JH	162	skb_queue_head(&h5->rel, skb);
	163	}
	164
	165	spin_unlock_irqrestore(&h5->unack.lock, flags);
	166
f674a057	167	wakeup:
3f27e95b JH	168	hci_uart_tx_wakeup(hu);
	169	}
	170
b509c02d LP	171	static void h5_peer_reset(struct hci_uart *hu)
	172	{
	173	struct h5 *h5 = hu->priv;
b509c02d LP	174
	175	BT_ERR("Peer device has reset");
	176
	177	h5->state = H5_UNINITIALIZED;
	178
	179	del_timer(&h5->timer);
	180
	181	skb_queue_purge(&h5->rel);
	182	skb_queue_purge(&h5->unrel);
	183	skb_queue_purge(&h5->unack);
	184
	185	h5->tx_seq = 0;
	186	h5->tx_ack = 0;
	187
882809fb MH	188	/* Send reset request to upper stack */
882809fb MH	189	hci_reset_dev(hu->hdev);
b509c02d LP	190	}
b509c02d LP	191
7dec65c8 JH	192	static int h5_open(struct hci_uart *hu)
7dec65c8 JH	193	{
7d664fba	194	struct h5 *h5;
40f10224	195	const unsigned char sync[] = { 0x01, 0x7e };
7d664fba JH	196
	197	BT_DBG("hu %p", hu);
	198
	199	h5 = kzalloc(sizeof(*h5), GFP_KERNEL);
	200	if (!h5)
	201	return -ENOMEM;
	202
	203	hu->priv = h5;
	204
	205	skb_queue_head_init(&h5->unack);
	206	skb_queue_head_init(&h5->rel);
	207	skb_queue_head_init(&h5->unrel);
	208
bc1f35b9 JH	209	h5_reset_rx(h5);
bc1f35b9 JH	210
3f27e95b JH	211	init_timer(&h5->timer);
	212	h5->timer.function = h5_timed_event;
	213	h5->timer.data = (unsigned long) hu;
	214
afdc944c JH	215	h5->tx_win = H5_TX_WIN_MAX;
afdc944c JH	216
cd1b4425 JH	217	set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags);
cd1b4425 JH	218
40f10224 JH	219	/* Send initial sync request */
	220	h5_link_control(hu, sync, sizeof(sync));
	221	mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
	222
7d664fba	223	return 0;
7dec65c8 JH	224	}
	225
	226	static int h5_close(struct hci_uart *hu)
	227	{
7d664fba JH	228	struct h5 *h5 = hu->priv;
7d664fba JH	229
c327cddd MK	230	del_timer_sync(&h5->timer);
c327cddd MK	231
7d664fba JH	232	skb_queue_purge(&h5->unack);
	233	skb_queue_purge(&h5->rel);
	234	skb_queue_purge(&h5->unrel);
	235
	236	kfree(h5);
	237
	238	return 0;
7dec65c8 JH	239	}
7dec65c8 JH	240
43eb12d7 JH	241	static void h5_pkt_cull(struct h5 *h5)
	242	{
	243	struct sk_buff skb, tmp;
	244	unsigned long flags;
	245	int i, to_remove;
	246	u8 seq;
	247
	248	spin_lock_irqsave(&h5->unack.lock, flags);
	249
	250	to_remove = skb_queue_len(&h5->unack);
40f10224 JH	251	if (to_remove == 0)
40f10224 JH	252	goto unlock;
43eb12d7 JH	253
	254	seq = h5->tx_seq;
	255
	256	while (to_remove > 0) {
	257	if (h5->rx_ack == seq)
	258	break;
	259
	260	to_remove--;
4807b518	261	seq = (seq - 1) & 0x07;
43eb12d7 JH	262	}
	263
	264	if (seq != h5->rx_ack)
	265	BT_ERR("Controller acked invalid packet");
	266
	267	i = 0;
	268	skb_queue_walk_safe(&h5->unack, skb, tmp) {
	269	if (i++ >= to_remove)
	270	break;
	271
	272	__skb_unlink(skb, &h5->unack);
	273	kfree_skb(skb);
	274	}
	275
	276	if (skb_queue_empty(&h5->unack))
	277	del_timer(&h5->timer);
	278
40f10224	279	unlock:
43eb12d7 JH	280	spin_unlock_irqrestore(&h5->unack.lock, flags);
	281	}
	282
bc1f35b9 JH	283	static void h5_handle_internal_rx(struct hci_uart *hu)
bc1f35b9 JH	284	{
40f10224 JH	285	struct h5 *h5 = hu->priv;
	286	const unsigned char sync_req[] = { 0x01, 0x7e };
	287	const unsigned char sync_rsp[] = { 0x02, 0x7d };
afdc944c JH	288	unsigned char conf_req[] = { 0x03, 0xfc, 0x01 };
afdc944c JH	289	const unsigned char conf_rsp[] = { 0x04, 0x7b };
10122d07 JH	290	const unsigned char wakeup_req[] = { 0x05, 0xfa };
	291	const unsigned char woken_req[] = { 0x06, 0xf9 };
	292	const unsigned char sleep_req[] = { 0x07, 0x78 };
40f10224 JH	293	const unsigned char *hdr = h5->rx_skb->data;
	294	const unsigned char *data = &h5->rx_skb->data[4];
	295
bc1f35b9	296	BT_DBG("%s", hu->hdev->name);
40f10224 JH	297
	298	if (H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT)
	299	return;
	300
	301	if (H5_HDR_LEN(hdr) < 2)
	302	return;
	303
afdc944c JH	304	conf_req[2] = h5_cfg_field(h5);
afdc944c JH	305
40f10224	306	if (memcmp(data, sync_req, 2) == 0) {
b509c02d LP	307	if (h5->state == H5_ACTIVE)
b509c02d LP	308	h5_peer_reset(hu);
40f10224 JH	309	h5_link_control(hu, sync_rsp, 2);
40f10224 JH	310	} else if (memcmp(data, sync_rsp, 2) == 0) {
b509c02d LP	311	if (h5->state == H5_ACTIVE)
b509c02d LP	312	h5_peer_reset(hu);
f674a057	313	h5->state = H5_INITIALIZED;
40f10224 JH	314	h5_link_control(hu, conf_req, 3);
	315	} else if (memcmp(data, conf_req, 2) == 0) {
	316	h5_link_control(hu, conf_rsp, 2);
	317	h5_link_control(hu, conf_req, 3);
	318	} else if (memcmp(data, conf_rsp, 2) == 0) {
afdc944c JH	319	if (H5_HDR_LEN(hdr) > 2)
	320	h5->tx_win = (data[2] & 7);
	321	BT_DBG("Three-wire init complete. tx_win %u", h5->tx_win);
f674a057	322	h5->state = H5_ACTIVE;
cd1b4425	323	hci_uart_init_ready(hu);
40f10224	324	return;
10122d07 JH	325	} else if (memcmp(data, sleep_req, 2) == 0) {
10122d07 JH	326	BT_DBG("Peer went to sleep");
95c5c220 JH	327	h5->sleep = H5_SLEEPING;
95c5c220 JH	328	return;
10122d07 JH	329	} else if (memcmp(data, woken_req, 2) == 0) {
10122d07 JH	330	BT_DBG("Peer woke up");
95c5c220 JH	331	h5->sleep = H5_AWAKE;
	332	} else if (memcmp(data, wakeup_req, 2) == 0) {
	333	BT_DBG("Peer requested wakeup");
	334	h5_link_control(hu, woken_req, 2);
	335	h5->sleep = H5_AWAKE;
40f10224 JH	336	} else {
	337	BT_DBG("Link Control: 0x%02hhx 0x%02hhx", data[0], data[1]);
	338	return;
	339	}
	340
	341	hci_uart_tx_wakeup(hu);
bc1f35b9 JH	342	}
	343
	344	static void h5_complete_rx_pkt(struct hci_uart *hu)
	345	{
	346	struct h5 *h5 = hu->priv;
43eb12d7	347	const unsigned char *hdr = h5->rx_skb->data;
bc1f35b9	348
43eb12d7	349	if (H5_HDR_RELIABLE(hdr)) {
40f10224	350	h5->tx_ack = (h5->tx_ack + 1) % 8;
e0482103	351	set_bit(H5_TX_ACK_REQ, &h5->flags);
40f10224	352	hci_uart_tx_wakeup(hu);
43eb12d7	353	}
bc1f35b9	354
43eb12d7 JH	355	h5->rx_ack = H5_HDR_ACK(hdr);
	356
	357	h5_pkt_cull(h5);
	358
	359	switch (H5_HDR_PKT_TYPE(hdr)) {
bc1f35b9 JH	360	case HCI_EVENT_PKT:
	361	case HCI_ACLDATA_PKT:
	362	case HCI_SCODATA_PKT:
43eb12d7	363	bt_cb(h5->rx_skb)->pkt_type = H5_HDR_PKT_TYPE(hdr);
bc1f35b9 JH	364
	365	/* Remove Three-wire header */
	366	skb_pull(h5->rx_skb, 4);
	367
e1a26170	368	hci_recv_frame(hu->hdev, h5->rx_skb);
bc1f35b9 JH	369	h5->rx_skb = NULL;
	370
	371	break;
	372
	373	default:
	374	h5_handle_internal_rx(hu);
	375	break;
	376	}
	377
	378	h5_reset_rx(h5);
	379	}
	380
	381	static int h5_rx_crc(struct hci_uart *hu, unsigned char c)
	382	{
bc1f35b9	383	h5_complete_rx_pkt(hu);
bc1f35b9 JH	384
	385	return 0;
	386	}
	387
	388	static int h5_rx_payload(struct hci_uart *hu, unsigned char c)
	389	{
	390	struct h5 *h5 = hu->priv;
	391	const unsigned char *hdr = h5->rx_skb->data;
	392
43eb12d7	393	if (H5_HDR_CRC(hdr)) {
bc1f35b9 JH	394	h5->rx_func = h5_rx_crc;
	395	h5->rx_pending = 2;
	396	} else {
	397	h5_complete_rx_pkt(hu);
bc1f35b9 JH	398	}
	399
	400	return 0;
	401	}
	402
	403	static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c)
	404	{
	405	struct h5 *h5 = hu->priv;
	406	const unsigned char *hdr = h5->rx_skb->data;
	407
40f10224 JH	408	BT_DBG("%s rx: seq %u ack %u crc %u rel %u type %u len %u",
	409	hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
	410	H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
	411	H5_HDR_LEN(hdr));
	412
bc1f35b9 JH	413	if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) {
	414	BT_ERR("Invalid header checksum");
	415	h5_reset_rx(h5);
	416	return 0;
	417	}
	418
40f10224	419	if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_ack) {
43eb12d7	420	BT_ERR("Out-of-order packet arrived (%u != %u)",
40f10224	421	H5_HDR_SEQ(hdr), h5->tx_ack);
43eb12d7 JH	422	h5_reset_rx(h5);
	423	return 0;
	424	}
	425
f674a057 JH	426	if (h5->state != H5_ACTIVE &&
	427	H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT) {
	428	BT_ERR("Non-link packet received in non-active state");
	429	h5_reset_rx(h5);
48439d50	430	return 0;
f674a057 JH	431	}
f674a057 JH	432
bc1f35b9	433	h5->rx_func = h5_rx_payload;
43eb12d7	434	h5->rx_pending = H5_HDR_LEN(hdr);
bc1f35b9 JH	435
	436	return 0;
	437	}
	438
	439	static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c)
	440	{
	441	struct h5 *h5 = hu->priv;
	442
bc1f35b9 JH	443	if (c == SLIP_DELIMITER)
	444	return 1;
	445
	446	h5->rx_func = h5_rx_3wire_hdr;
	447	h5->rx_pending = 4;
	448
	449	h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC);
	450	if (!h5->rx_skb) {
	451	BT_ERR("Can't allocate mem for new packet");
	452	h5_reset_rx(h5);
	453	return -ENOMEM;
	454	}
	455
	456	h5->rx_skb->dev = (void *) hu->hdev;
	457
	458	return 0;
	459	}
	460
	461	static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c)
	462	{
	463	struct h5 *h5 = hu->priv;
	464
bc1f35b9 JH	465	if (c == SLIP_DELIMITER)
	466	h5->rx_func = h5_rx_pkt_start;
	467
	468	return 1;
	469	}
	470
	471	static void h5_unslip_one_byte(struct h5 *h5, unsigned char c)
	472	{
	473	const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC;
	474	const u8 *byte = &c;
	475
e0482103 JH	476	if (!test_bit(H5_RX_ESC, &h5->flags) && c == SLIP_ESC) {
e0482103 JH	477	set_bit(H5_RX_ESC, &h5->flags);
bc1f35b9 JH	478	return;
	479	}
	480
e0482103	481	if (test_and_clear_bit(H5_RX_ESC, &h5->flags)) {
bc1f35b9 JH	482	switch (c) {
	483	case SLIP_ESC_DELIM:
	484	byte = &delim;
	485	break;
	486	case SLIP_ESC_ESC:
	487	byte = &esc;
	488	break;
	489	default:
	490	BT_ERR("Invalid esc byte 0x%02hhx", c);
	491	h5_reset_rx(h5);
	492	return;
	493	}
bc1f35b9 JH	494	}
	495
	496	memcpy(skb_put(h5->rx_skb, 1), byte, 1);
	497	h5->rx_pending--;
	498
255a68e0	499	BT_DBG("unsliped 0x%02hhx, rx_pending %zu", *byte, h5->rx_pending);
bc1f35b9 JH	500	}
	501
	502	static void h5_reset_rx(struct h5 *h5)
	503	{
	504	if (h5->rx_skb) {
	505	kfree_skb(h5->rx_skb);
	506	h5->rx_skb = NULL;
	507	}
	508
	509	h5->rx_func = h5_rx_delimiter;
	510	h5->rx_pending = 0;
e0482103	511	clear_bit(H5_RX_ESC, &h5->flags);
bc1f35b9 JH	512	}
bc1f35b9 JH	513
7dec65c8 JH	514	static int h5_recv(struct hci_uart hu, void data, int count)
7dec65c8 JH	515	{
bc1f35b9 JH	516	struct h5 *h5 = hu->priv;
	517	unsigned char *ptr = data;
	518
255a68e0 JH	519	BT_DBG("%s pending %zu count %d", hu->hdev->name, h5->rx_pending,
255a68e0 JH	520	count);
bc1f35b9 JH	521
	522	while (count > 0) {
	523	int processed;
	524
	525	if (h5->rx_pending > 0) {
	526	if (*ptr == SLIP_DELIMITER) {
	527	BT_ERR("Too short H5 packet");
	528	h5_reset_rx(h5);
	529	continue;
	530	}
	531
	532	h5_unslip_one_byte(h5, *ptr);
	533
	534	ptr++; count--;
	535	continue;
	536	}
	537
	538	processed = h5->rx_func(hu, *ptr);
	539	if (processed < 0)
	540	return processed;
	541
	542	ptr += processed;
	543	count -= processed;
	544	}
	545
	546	return 0;
7dec65c8 JH	547	}
	548
	549	static int h5_enqueue(struct hci_uart hu, struct sk_buff skb)
	550	{
7d664fba JH	551	struct h5 *h5 = hu->priv;
	552
	553	if (skb->len > 0xfff) {
	554	BT_ERR("Packet too long (%u bytes)", skb->len);
	555	kfree_skb(skb);
	556	return 0;
	557	}
	558
f674a057 JH	559	if (h5->state != H5_ACTIVE) {
	560	BT_ERR("Ignoring HCI data in non-active state");
	561	kfree_skb(skb);
	562	return 0;
	563	}
	564
7d664fba JH	565	switch (bt_cb(skb)->pkt_type) {
	566	case HCI_ACLDATA_PKT:
	567	case HCI_COMMAND_PKT:
	568	skb_queue_tail(&h5->rel, skb);
	569	break;
	570
	571	case HCI_SCODATA_PKT:
	572	skb_queue_tail(&h5->unrel, skb);
	573	break;
	574
	575	default:
	576	BT_ERR("Unknown packet type %u", bt_cb(skb)->pkt_type);
	577	kfree_skb(skb);
	578	break;
	579	}
	580
	581	return 0;
	582	}
	583
c0a1b73c JH	584	static void h5_slip_delim(struct sk_buff *skb)
	585	{
	586	const char delim = SLIP_DELIMITER;
	587
	588	memcpy(skb_put(skb, 1), &delim, 1);
	589	}
	590
	591	static void h5_slip_one_byte(struct sk_buff *skb, u8 c)
	592	{
	593	const char esc_delim[2] = { SLIP_ESC, SLIP_ESC_DELIM };
	594	const char esc_esc[2] = { SLIP_ESC, SLIP_ESC_ESC };
	595
	596	switch (c) {
	597	case SLIP_DELIMITER:
	598	memcpy(skb_put(skb, 2), &esc_delim, 2);
	599	break;
	600	case SLIP_ESC:
	601	memcpy(skb_put(skb, 2), &esc_esc, 2);
	602	break;
	603	default:
	604	memcpy(skb_put(skb, 1), &c, 1);
	605	}
	606	}
	607
c826ed09 JH	608	static bool valid_packet_type(u8 type)
	609	{
	610	switch (type) {
	611	case HCI_ACLDATA_PKT:
	612	case HCI_COMMAND_PKT:
	613	case HCI_SCODATA_PKT:
	614	case HCI_3WIRE_LINK_PKT:
	615	case HCI_3WIRE_ACK_PKT:
	616	return true;
	617	default:
	618	return false;
	619	}
	620	}
	621
	622	static struct sk_buff h5_prepare_pkt(struct hci_uart hu, u8 pkt_type,
	623	const u8 *data, size_t len)
7d664fba	624	{
40f10224	625	struct h5 *h5 = hu->priv;
c0a1b73c JH	626	struct sk_buff *nskb;
	627	u8 hdr[4];
	628	int i;
	629
c826ed09 JH	630	if (!valid_packet_type(pkt_type)) {
	631	BT_ERR("Unknown packet type %u", pkt_type);
	632	return NULL;
	633	}
	634
c0a1b73c JH	635	/*
	636	* Max len of packet: (original len + 4 (H5 hdr) + 2 (crc)) * 2
	637	* (because bytes 0xc0 and 0xdb are escaped, worst case is when
	638	* the packet is all made of 0xc0 and 0xdb) + 2 (0xc0
	639	* delimiters at start and end).
	640	*/
	641	nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
	642	if (!nskb)
	643	return NULL;
	644
	645	bt_cb(nskb)->pkt_type = pkt_type;
	646
	647	h5_slip_delim(nskb);
	648
40f10224	649	hdr[0] = h5->tx_ack << 3;
e0482103	650	clear_bit(H5_TX_ACK_REQ, &h5->flags);
c0a1b73c	651
c826ed09 JH	652	/* Reliable packet? */
c826ed09 JH	653	if (pkt_type == HCI_ACLDATA_PKT \|\| pkt_type == HCI_COMMAND_PKT) {
c0a1b73c	654	hdr[0] \|= 1 << 7;
43eb12d7 JH	655	hdr[0] \|= h5->tx_seq;
43eb12d7 JH	656	h5->tx_seq = (h5->tx_seq + 1) % 8;
c0a1b73c JH	657	}
	658
	659	hdr[1] = pkt_type \| ((len & 0x0f) << 4);
	660	hdr[2] = len >> 4;
	661	hdr[3] = ~((hdr[0] + hdr[1] + hdr[2]) & 0xff);
	662
40f10224 JH	663	BT_DBG("%s tx: seq %u ack %u crc %u rel %u type %u len %u",
	664	hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
	665	H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
	666	H5_HDR_LEN(hdr));
	667
c0a1b73c JH	668	for (i = 0; i < 4; i++)
	669	h5_slip_one_byte(nskb, hdr[i]);
	670
	671	for (i = 0; i < len; i++)
	672	h5_slip_one_byte(nskb, data[i]);
	673
	674	h5_slip_delim(nskb);
	675
	676	return nskb;
	677	}
	678
7dec65c8 JH	679	static struct sk_buff h5_dequeue(struct hci_uart hu)
7dec65c8 JH	680	{
7d664fba	681	struct h5 *h5 = hu->priv;
3f27e95b	682	unsigned long flags;
7d664fba JH	683	struct sk_buff skb, nskb;
7d664fba JH	684
95c5c220 JH	685	if (h5->sleep != H5_AWAKE) {
	686	const unsigned char wakeup_req[] = { 0x05, 0xfa };
	687
	688	if (h5->sleep == H5_WAKING_UP)
	689	return NULL;
	690
	691	h5->sleep = H5_WAKING_UP;
	692	BT_DBG("Sending wakeup request");
	693
	694	mod_timer(&h5->timer, jiffies + HZ / 100);
	695	return h5_prepare_pkt(hu, HCI_3WIRE_LINK_PKT, wakeup_req, 2);
	696	}
	697
a08b15e6 VI	698	skb = skb_dequeue(&h5->unrel);
a08b15e6 VI	699	if (skb != NULL) {
40f10224	700	nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
c0a1b73c	701	skb->data, skb->len);
7d664fba JH	702	if (nskb) {
	703	kfree_skb(skb);
	704	return nskb;
	705	}
	706
	707	skb_queue_head(&h5->unrel, skb);
	708	BT_ERR("Could not dequeue pkt because alloc_skb failed");
	709	}
	710
3f27e95b JH	711	spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
3f27e95b JH	712
afdc944c	713	if (h5->unack.qlen >= h5->tx_win)
3f27e95b JH	714	goto unlock;
3f27e95b JH	715
a08b15e6 VI	716	skb = skb_dequeue(&h5->rel);
a08b15e6 VI	717	if (skb != NULL) {
40f10224	718	nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
c0a1b73c	719	skb->data, skb->len);
3f27e95b JH	720	if (nskb) {
	721	__skb_queue_tail(&h5->unack, skb);
	722	mod_timer(&h5->timer, jiffies + H5_ACK_TIMEOUT);
	723	spin_unlock_irqrestore(&h5->unack.lock, flags);
	724	return nskb;
	725	}
	726
	727	skb_queue_head(&h5->rel, skb);
	728	BT_ERR("Could not dequeue pkt because alloc_skb failed");
	729	}
	730
	731	unlock:
	732	spin_unlock_irqrestore(&h5->unack.lock, flags);
	733
e0482103	734	if (test_bit(H5_TX_ACK_REQ, &h5->flags))
40f10224	735	return h5_prepare_pkt(hu, HCI_3WIRE_ACK_PKT, NULL, 0);
7d664fba	736
7dec65c8 JH	737	return NULL;
	738	}
	739
	740	static int h5_flush(struct hci_uart *hu)
	741	{
7d664fba JH	742	BT_DBG("hu %p", hu);
7d664fba JH	743	return 0;
7dec65c8 JH	744	}
	745
	746	static struct hci_uart_proto h5p = {
	747	.id = HCI_UART_3WIRE,
	748	.open = h5_open,
	749	.close = h5_close,
	750	.recv = h5_recv,
	751	.enqueue = h5_enqueue,
	752	.dequeue = h5_dequeue,
	753	.flush = h5_flush,
	754	};
	755
	756	int __init h5_init(void)
	757	{
	758	int err = hci_uart_register_proto(&h5p);
	759
	760	if (!err)
	761	BT_INFO("HCI Three-wire UART (H5) protocol initialized");
	762	else
	763	BT_ERR("HCI Three-wire UART (H5) protocol init failed");
	764
	765	return err;
	766	}
	767
	768	int __exit h5_deinit(void)
	769	{
	770	return hci_uart_unregister_proto(&h5p);
	771	}