[mirror_ubuntu-artful-kernel.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) & 0x0f) + ((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;

	hci_skb_pkt_type(nskb) = HCI_3WIRE_LINK_PKT;

	skb_put_data(nskb, data, len);

	skb_queue_tail(&h5->unrel, nskb);
}

static u8 h5_cfg_field(struct h5 *h5)
{
	/* Sliding window size (first 3 bits) */
	return h5->tx_win & 0x07;
}

static void h5_timed_event(unsigned long arg)
{
	const unsigned char sync_req[] = { 0x01, 0x7e };
	unsigned char conf_req[3] = { 0x03, 0xfc };
	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);

	setup_timer(&h5->timer, h5_timed_event, (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[3] = { 0x03, 0xfc };
	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);
		if (h5->state != H5_ACTIVE)
		    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] & 0x07);
		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:
		hci_skb_pkt_type(h5->rx_skb) = 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;
		}
	}

	skb_put_data(h5->rx_skb, 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, const void *data, int count)
{
	struct h5 *h5 = hu->priv;
	const 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 (hci_skb_pkt_type(skb)) {
	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", hci_skb_pkt_type(skb));
		kfree_skb(skb);
		break;
	}

	return 0;
}

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

	skb_put_data(skb, &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:
		skb_put_data(skb, &esc_delim, 2);
		break;
	case SLIP_ESC:
		skb_put_data(skb, &esc_esc, 2);
		break;
	default:
		skb_put_data(skb, &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;

	hci_skb_pkt_type(nskb) = 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) {
		nskb = h5_prepare_pkt(hu, hci_skb_pkt_type(skb),
				      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) {
		nskb = h5_prepare_pkt(hu, hci_skb_pkt_type(skb),
				      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 const struct hci_uart_proto h5p = {
	.id		= HCI_UART_3WIRE,
	.name		= "Three-wire (H5)",
	.open		= h5_open,
	.close		= h5_close,
	.recv		= h5_recv,
	.enqueue	= h5_enqueue,
	.dequeue	= h5_dequeue,
	.flush		= h5_flush,
};

int __init h5_init(void)
{
	return hci_uart_register_proto(&h5p);
}

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)
4223f368	54	#define H5_HDR_LEN(hdr) ((((hdr)[1] >> 4) & 0x0f) + ((hdr)[2] << 4))
01977c0b	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
fa4cf04e	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
618e8bc2	110	hci_skb_pkt_type(nskb) = HCI_3WIRE_LINK_PKT;
f674a057	111
59ae1d12	112	skb_put_data(nskb, data, len);
f674a057 JH	113
	114	skb_queue_tail(&h5->unrel, nskb);
	115	}
	116
afdc944c JH	117	static u8 h5_cfg_field(struct h5 *h5)
afdc944c JH	118	{
afdc944c	119	/* Sliding window size (first 3 bits) */
742c5951	120	return h5->tx_win & 0x07;
afdc944c JH	121	}
afdc944c JH	122
3f27e95b JH	123	static void h5_timed_event(unsigned long arg)
3f27e95b JH	124	{
f674a057	125	const unsigned char sync_req[] = { 0x01, 0x7e };
87a6b9bd	126	unsigned char conf_req[3] = { 0x03, 0xfc };
4a2fa2b8	127	struct hci_uart hu = (struct hci_uart )arg;
3f27e95b JH	128	struct h5 *h5 = hu->priv;
	129	struct sk_buff *skb;
	130	unsigned long flags;
	131
95c5c220 JH	132	BT_DBG("%s", hu->hdev->name);
95c5c220 JH	133
f674a057 JH	134	if (h5->state == H5_UNINITIALIZED)
	135	h5_link_control(hu, sync_req, sizeof(sync_req));
	136
afdc944c JH	137	if (h5->state == H5_INITIALIZED) {
afdc944c JH	138	conf_req[2] = h5_cfg_field(h5);
f674a057	139	h5_link_control(hu, conf_req, sizeof(conf_req));
afdc944c	140	}
f674a057 JH	141
	142	if (h5->state != H5_ACTIVE) {
	143	mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
	144	goto wakeup;
	145	}
	146
95c5c220 JH	147	if (h5->sleep != H5_AWAKE) {
	148	h5->sleep = H5_SLEEPING;
	149	goto wakeup;
	150	}
	151
3f27e95b JH	152	BT_DBG("hu %p retransmitting %u pkts", hu, h5->unack.qlen);
	153
	154	spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
	155
	156	while ((skb = __skb_dequeue_tail(&h5->unack)) != NULL) {
43eb12d7	157	h5->tx_seq = (h5->tx_seq - 1) & 0x07;
3f27e95b JH	158	skb_queue_head(&h5->rel, skb);
	159	}
	160
	161	spin_unlock_irqrestore(&h5->unack.lock, flags);
	162
f674a057	163	wakeup:
3f27e95b JH	164	hci_uart_tx_wakeup(hu);
	165	}
	166
b509c02d LP	167	static void h5_peer_reset(struct hci_uart *hu)
	168	{
	169	struct h5 *h5 = hu->priv;
b509c02d LP	170
	171	BT_ERR("Peer device has reset");
	172
	173	h5->state = H5_UNINITIALIZED;
	174
	175	del_timer(&h5->timer);
	176
	177	skb_queue_purge(&h5->rel);
	178	skb_queue_purge(&h5->unrel);
	179	skb_queue_purge(&h5->unack);
	180
	181	h5->tx_seq = 0;
	182	h5->tx_ack = 0;
	183
882809fb MH	184	/* Send reset request to upper stack */
882809fb MH	185	hci_reset_dev(hu->hdev);
b509c02d LP	186	}
b509c02d LP	187
7dec65c8 JH	188	static int h5_open(struct hci_uart *hu)
7dec65c8 JH	189	{
7d664fba	190	struct h5 *h5;
40f10224	191	const unsigned char sync[] = { 0x01, 0x7e };
7d664fba JH	192
	193	BT_DBG("hu %p", hu);
	194
	195	h5 = kzalloc(sizeof(*h5), GFP_KERNEL);
	196	if (!h5)
	197	return -ENOMEM;
	198
	199	hu->priv = h5;
	200
	201	skb_queue_head_init(&h5->unack);
	202	skb_queue_head_init(&h5->rel);
	203	skb_queue_head_init(&h5->unrel);
	204
bc1f35b9 JH	205	h5_reset_rx(h5);
bc1f35b9 JH	206
a1e0d043	207	setup_timer(&h5->timer, h5_timed_event, (unsigned long)hu);
3f27e95b	208
afdc944c JH	209	h5->tx_win = H5_TX_WIN_MAX;
afdc944c JH	210
cd1b4425 JH	211	set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags);
cd1b4425 JH	212
40f10224 JH	213	/* Send initial sync request */
	214	h5_link_control(hu, sync, sizeof(sync));
	215	mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
	216
7d664fba	217	return 0;
7dec65c8 JH	218	}
	219
	220	static int h5_close(struct hci_uart *hu)
	221	{
7d664fba JH	222	struct h5 *h5 = hu->priv;
7d664fba JH	223
c327cddd MK	224	del_timer_sync(&h5->timer);
c327cddd MK	225
7d664fba JH	226	skb_queue_purge(&h5->unack);
	227	skb_queue_purge(&h5->rel);
	228	skb_queue_purge(&h5->unrel);
	229
	230	kfree(h5);
	231
	232	return 0;
7dec65c8 JH	233	}
7dec65c8 JH	234
43eb12d7 JH	235	static void h5_pkt_cull(struct h5 *h5)
	236	{
	237	struct sk_buff skb, tmp;
	238	unsigned long flags;
	239	int i, to_remove;
	240	u8 seq;
	241
	242	spin_lock_irqsave(&h5->unack.lock, flags);
	243
	244	to_remove = skb_queue_len(&h5->unack);
40f10224 JH	245	if (to_remove == 0)
40f10224 JH	246	goto unlock;
43eb12d7 JH	247
	248	seq = h5->tx_seq;
	249
	250	while (to_remove > 0) {
	251	if (h5->rx_ack == seq)
	252	break;
	253
	254	to_remove--;
4807b518	255	seq = (seq - 1) & 0x07;
43eb12d7 JH	256	}
	257
	258	if (seq != h5->rx_ack)
	259	BT_ERR("Controller acked invalid packet");
	260
	261	i = 0;
	262	skb_queue_walk_safe(&h5->unack, skb, tmp) {
	263	if (i++ >= to_remove)
	264	break;
	265
	266	__skb_unlink(skb, &h5->unack);
	267	kfree_skb(skb);
	268	}
	269
	270	if (skb_queue_empty(&h5->unack))
	271	del_timer(&h5->timer);
	272
40f10224	273	unlock:
43eb12d7 JH	274	spin_unlock_irqrestore(&h5->unack.lock, flags);
	275	}
	276
bc1f35b9 JH	277	static void h5_handle_internal_rx(struct hci_uart *hu)
bc1f35b9 JH	278	{
40f10224 JH	279	struct h5 *h5 = hu->priv;
	280	const unsigned char sync_req[] = { 0x01, 0x7e };
	281	const unsigned char sync_rsp[] = { 0x02, 0x7d };
87a6b9bd	282	unsigned char conf_req[3] = { 0x03, 0xfc };
afdc944c	283	const unsigned char conf_rsp[] = { 0x04, 0x7b };
10122d07 JH	284	const unsigned char wakeup_req[] = { 0x05, 0xfa };
	285	const unsigned char woken_req[] = { 0x06, 0xf9 };
	286	const unsigned char sleep_req[] = { 0x07, 0x78 };
40f10224 JH	287	const unsigned char *hdr = h5->rx_skb->data;
	288	const unsigned char *data = &h5->rx_skb->data[4];
	289
bc1f35b9	290	BT_DBG("%s", hu->hdev->name);
40f10224 JH	291
	292	if (H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT)
	293	return;
	294
	295	if (H5_HDR_LEN(hdr) < 2)
	296	return;
	297
afdc944c JH	298	conf_req[2] = h5_cfg_field(h5);
afdc944c JH	299
40f10224	300	if (memcmp(data, sync_req, 2) == 0) {
b509c02d LP	301	if (h5->state == H5_ACTIVE)
b509c02d LP	302	h5_peer_reset(hu);
40f10224 JH	303	h5_link_control(hu, sync_rsp, 2);
40f10224 JH	304	} else if (memcmp(data, sync_rsp, 2) == 0) {
b509c02d LP	305	if (h5->state == H5_ACTIVE)
b509c02d LP	306	h5_peer_reset(hu);
f674a057	307	h5->state = H5_INITIALIZED;
40f10224 JH	308	h5_link_control(hu, conf_req, 3);
	309	} else if (memcmp(data, conf_req, 2) == 0) {
	310	h5_link_control(hu, conf_rsp, 2);
5e7d7c7a PE	311	if (h5->state != H5_ACTIVE)
5e7d7c7a PE	312	h5_link_control(hu, conf_req, 3);
40f10224	313	} else if (memcmp(data, conf_rsp, 2) == 0) {
afdc944c	314	if (H5_HDR_LEN(hdr) > 2)
1d3a1e69	315	h5->tx_win = (data[2] & 0x07);
afdc944c	316	BT_DBG("Three-wire init complete. tx_win %u", h5->tx_win);
f674a057	317	h5->state = H5_ACTIVE;
cd1b4425	318	hci_uart_init_ready(hu);
40f10224	319	return;
10122d07 JH	320	} else if (memcmp(data, sleep_req, 2) == 0) {
10122d07 JH	321	BT_DBG("Peer went to sleep");
95c5c220 JH	322	h5->sleep = H5_SLEEPING;
95c5c220 JH	323	return;
10122d07 JH	324	} else if (memcmp(data, woken_req, 2) == 0) {
10122d07 JH	325	BT_DBG("Peer woke up");
95c5c220 JH	326	h5->sleep = H5_AWAKE;
	327	} else if (memcmp(data, wakeup_req, 2) == 0) {
	328	BT_DBG("Peer requested wakeup");
	329	h5_link_control(hu, woken_req, 2);
	330	h5->sleep = H5_AWAKE;
40f10224 JH	331	} else {
	332	BT_DBG("Link Control: 0x%02hhx 0x%02hhx", data[0], data[1]);
	333	return;
	334	}
	335
	336	hci_uart_tx_wakeup(hu);
bc1f35b9 JH	337	}
	338
	339	static void h5_complete_rx_pkt(struct hci_uart *hu)
	340	{
	341	struct h5 *h5 = hu->priv;
43eb12d7	342	const unsigned char *hdr = h5->rx_skb->data;
bc1f35b9	343
43eb12d7	344	if (H5_HDR_RELIABLE(hdr)) {
40f10224	345	h5->tx_ack = (h5->tx_ack + 1) % 8;
e0482103	346	set_bit(H5_TX_ACK_REQ, &h5->flags);
40f10224	347	hci_uart_tx_wakeup(hu);
43eb12d7	348	}
bc1f35b9	349
43eb12d7 JH	350	h5->rx_ack = H5_HDR_ACK(hdr);
	351
	352	h5_pkt_cull(h5);
	353
	354	switch (H5_HDR_PKT_TYPE(hdr)) {
bc1f35b9 JH	355	case HCI_EVENT_PKT:
	356	case HCI_ACLDATA_PKT:
	357	case HCI_SCODATA_PKT:
618e8bc2	358	hci_skb_pkt_type(h5->rx_skb) = H5_HDR_PKT_TYPE(hdr);
bc1f35b9 JH	359
	360	/* Remove Three-wire header */
	361	skb_pull(h5->rx_skb, 4);
	362
e1a26170	363	hci_recv_frame(hu->hdev, h5->rx_skb);
bc1f35b9 JH	364	h5->rx_skb = NULL;
	365
	366	break;
	367
	368	default:
	369	h5_handle_internal_rx(hu);
	370	break;
	371	}
	372
	373	h5_reset_rx(h5);
	374	}
	375
	376	static int h5_rx_crc(struct hci_uart *hu, unsigned char c)
	377	{
bc1f35b9	378	h5_complete_rx_pkt(hu);
bc1f35b9 JH	379
	380	return 0;
	381	}
	382
	383	static int h5_rx_payload(struct hci_uart *hu, unsigned char c)
	384	{
	385	struct h5 *h5 = hu->priv;
	386	const unsigned char *hdr = h5->rx_skb->data;
	387
43eb12d7	388	if (H5_HDR_CRC(hdr)) {
bc1f35b9 JH	389	h5->rx_func = h5_rx_crc;
	390	h5->rx_pending = 2;
	391	} else {
	392	h5_complete_rx_pkt(hu);
bc1f35b9 JH	393	}
	394
	395	return 0;
	396	}
	397
	398	static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c)
	399	{
	400	struct h5 *h5 = hu->priv;
	401	const unsigned char *hdr = h5->rx_skb->data;
	402
40f10224 JH	403	BT_DBG("%s rx: seq %u ack %u crc %u rel %u type %u len %u",
	404	hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
	405	H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
	406	H5_HDR_LEN(hdr));
	407
bc1f35b9 JH	408	if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) {
	409	BT_ERR("Invalid header checksum");
	410	h5_reset_rx(h5);
	411	return 0;
	412	}
	413
40f10224	414	if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_ack) {
43eb12d7	415	BT_ERR("Out-of-order packet arrived (%u != %u)",
40f10224	416	H5_HDR_SEQ(hdr), h5->tx_ack);
43eb12d7 JH	417	h5_reset_rx(h5);
	418	return 0;
	419	}
	420
f674a057 JH	421	if (h5->state != H5_ACTIVE &&
	422	H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT) {
	423	BT_ERR("Non-link packet received in non-active state");
	424	h5_reset_rx(h5);
48439d50	425	return 0;
f674a057 JH	426	}
f674a057 JH	427
bc1f35b9	428	h5->rx_func = h5_rx_payload;
43eb12d7	429	h5->rx_pending = H5_HDR_LEN(hdr);
bc1f35b9 JH	430
	431	return 0;
	432	}
	433
	434	static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c)
	435	{
	436	struct h5 *h5 = hu->priv;
	437
bc1f35b9 JH	438	if (c == SLIP_DELIMITER)
	439	return 1;
	440
	441	h5->rx_func = h5_rx_3wire_hdr;
	442	h5->rx_pending = 4;
	443
	444	h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC);
	445	if (!h5->rx_skb) {
	446	BT_ERR("Can't allocate mem for new packet");
	447	h5_reset_rx(h5);
	448	return -ENOMEM;
	449	}
	450
4a2fa2b8	451	h5->rx_skb->dev = (void *)hu->hdev;
bc1f35b9 JH	452
	453	return 0;
	454	}
	455
	456	static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c)
	457	{
	458	struct h5 *h5 = hu->priv;
	459
bc1f35b9 JH	460	if (c == SLIP_DELIMITER)
	461	h5->rx_func = h5_rx_pkt_start;
	462
	463	return 1;
	464	}
	465
	466	static void h5_unslip_one_byte(struct h5 *h5, unsigned char c)
	467	{
	468	const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC;
	469	const u8 *byte = &c;
	470
e0482103 JH	471	if (!test_bit(H5_RX_ESC, &h5->flags) && c == SLIP_ESC) {
e0482103 JH	472	set_bit(H5_RX_ESC, &h5->flags);
bc1f35b9 JH	473	return;
	474	}
	475
e0482103	476	if (test_and_clear_bit(H5_RX_ESC, &h5->flags)) {
bc1f35b9 JH	477	switch (c) {
	478	case SLIP_ESC_DELIM:
	479	byte = &delim;
	480	break;
	481	case SLIP_ESC_ESC:
	482	byte = &esc;
	483	break;
	484	default:
	485	BT_ERR("Invalid esc byte 0x%02hhx", c);
	486	h5_reset_rx(h5);
	487	return;
	488	}
bc1f35b9 JH	489	}
bc1f35b9 JH	490
59ae1d12	491	skb_put_data(h5->rx_skb, byte, 1);
bc1f35b9 JH	492	h5->rx_pending--;
bc1f35b9 JH	493
255a68e0	494	BT_DBG("unsliped 0x%02hhx, rx_pending %zu", *byte, h5->rx_pending);
bc1f35b9 JH	495	}
	496
	497	static void h5_reset_rx(struct h5 *h5)
	498	{
	499	if (h5->rx_skb) {
	500	kfree_skb(h5->rx_skb);
	501	h5->rx_skb = NULL;
	502	}
	503
	504	h5->rx_func = h5_rx_delimiter;
	505	h5->rx_pending = 0;
e0482103	506	clear_bit(H5_RX_ESC, &h5->flags);
bc1f35b9 JH	507	}
bc1f35b9 JH	508
9d1c40eb	509	static int h5_recv(struct hci_uart hu, const void data, int count)
7dec65c8	510	{
bc1f35b9	511	struct h5 *h5 = hu->priv;
9d1c40eb	512	const unsigned char *ptr = data;
bc1f35b9	513
255a68e0 JH	514	BT_DBG("%s pending %zu count %d", hu->hdev->name, h5->rx_pending,
255a68e0 JH	515	count);
bc1f35b9 JH	516
	517	while (count > 0) {
	518	int processed;
	519
	520	if (h5->rx_pending > 0) {
	521	if (*ptr == SLIP_DELIMITER) {
	522	BT_ERR("Too short H5 packet");
	523	h5_reset_rx(h5);
	524	continue;
	525	}
	526
	527	h5_unslip_one_byte(h5, *ptr);
	528
	529	ptr++; count--;
	530	continue;
	531	}
	532
	533	processed = h5->rx_func(hu, *ptr);
	534	if (processed < 0)
	535	return processed;
	536
	537	ptr += processed;
	538	count -= processed;
	539	}
	540
	541	return 0;
7dec65c8 JH	542	}
	543
	544	static int h5_enqueue(struct hci_uart hu, struct sk_buff skb)
	545	{
7d664fba JH	546	struct h5 *h5 = hu->priv;
	547
	548	if (skb->len > 0xfff) {
	549	BT_ERR("Packet too long (%u bytes)", skb->len);
	550	kfree_skb(skb);
	551	return 0;
	552	}
	553
f674a057 JH	554	if (h5->state != H5_ACTIVE) {
	555	BT_ERR("Ignoring HCI data in non-active state");
	556	kfree_skb(skb);
	557	return 0;
	558	}
	559
618e8bc2	560	switch (hci_skb_pkt_type(skb)) {
7d664fba JH	561	case HCI_ACLDATA_PKT:
	562	case HCI_COMMAND_PKT:
	563	skb_queue_tail(&h5->rel, skb);
	564	break;
	565
	566	case HCI_SCODATA_PKT:
	567	skb_queue_tail(&h5->unrel, skb);
	568	break;
	569
	570	default:
618e8bc2	571	BT_ERR("Unknown packet type %u", hci_skb_pkt_type(skb));
7d664fba JH	572	kfree_skb(skb);
	573	break;
	574	}
	575
	576	return 0;
	577	}
	578
c0a1b73c JH	579	static void h5_slip_delim(struct sk_buff *skb)
	580	{
	581	const char delim = SLIP_DELIMITER;
	582
59ae1d12	583	skb_put_data(skb, &delim, 1);
c0a1b73c JH	584	}
	585
	586	static void h5_slip_one_byte(struct sk_buff *skb, u8 c)
	587	{
	588	const char esc_delim[2] = { SLIP_ESC, SLIP_ESC_DELIM };
	589	const char esc_esc[2] = { SLIP_ESC, SLIP_ESC_ESC };
	590
	591	switch (c) {
	592	case SLIP_DELIMITER:
59ae1d12	593	skb_put_data(skb, &esc_delim, 2);
c0a1b73c JH	594	break;
c0a1b73c JH	595	case SLIP_ESC:
59ae1d12	596	skb_put_data(skb, &esc_esc, 2);
c0a1b73c JH	597	break;
c0a1b73c JH	598	default:
59ae1d12	599	skb_put_data(skb, &c, 1);
c0a1b73c JH	600	}
	601	}
	602
c826ed09 JH	603	static bool valid_packet_type(u8 type)
	604	{
	605	switch (type) {
	606	case HCI_ACLDATA_PKT:
	607	case HCI_COMMAND_PKT:
	608	case HCI_SCODATA_PKT:
	609	case HCI_3WIRE_LINK_PKT:
	610	case HCI_3WIRE_ACK_PKT:
	611	return true;
	612	default:
	613	return false;
	614	}
	615	}
	616
	617	static struct sk_buff h5_prepare_pkt(struct hci_uart hu, u8 pkt_type,
	618	const u8 *data, size_t len)
7d664fba	619	{
40f10224	620	struct h5 *h5 = hu->priv;
c0a1b73c JH	621	struct sk_buff *nskb;
	622	u8 hdr[4];
	623	int i;
	624
c826ed09 JH	625	if (!valid_packet_type(pkt_type)) {
	626	BT_ERR("Unknown packet type %u", pkt_type);
	627	return NULL;
	628	}
	629
c0a1b73c JH	630	/*
	631	* Max len of packet: (original len + 4 (H5 hdr) + 2 (crc)) * 2
	632	* (because bytes 0xc0 and 0xdb are escaped, worst case is when
	633	* the packet is all made of 0xc0 and 0xdb) + 2 (0xc0
	634	* delimiters at start and end).
	635	*/
	636	nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
	637	if (!nskb)
	638	return NULL;
	639
618e8bc2	640	hci_skb_pkt_type(nskb) = pkt_type;
c0a1b73c JH	641
	642	h5_slip_delim(nskb);
	643
40f10224	644	hdr[0] = h5->tx_ack << 3;
e0482103	645	clear_bit(H5_TX_ACK_REQ, &h5->flags);
c0a1b73c	646
c826ed09 JH	647	/* Reliable packet? */
c826ed09 JH	648	if (pkt_type == HCI_ACLDATA_PKT \|\| pkt_type == HCI_COMMAND_PKT) {
c0a1b73c	649	hdr[0] \|= 1 << 7;
43eb12d7 JH	650	hdr[0] \|= h5->tx_seq;
43eb12d7 JH	651	h5->tx_seq = (h5->tx_seq + 1) % 8;
c0a1b73c JH	652	}
	653
	654	hdr[1] = pkt_type \| ((len & 0x0f) << 4);
	655	hdr[2] = len >> 4;
	656	hdr[3] = ~((hdr[0] + hdr[1] + hdr[2]) & 0xff);
	657
40f10224 JH	658	BT_DBG("%s tx: seq %u ack %u crc %u rel %u type %u len %u",
	659	hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
	660	H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
	661	H5_HDR_LEN(hdr));
	662
c0a1b73c JH	663	for (i = 0; i < 4; i++)
	664	h5_slip_one_byte(nskb, hdr[i]);
	665
	666	for (i = 0; i < len; i++)
	667	h5_slip_one_byte(nskb, data[i]);
	668
	669	h5_slip_delim(nskb);
	670
	671	return nskb;
	672	}
	673
7dec65c8 JH	674	static struct sk_buff h5_dequeue(struct hci_uart hu)
7dec65c8 JH	675	{
7d664fba	676	struct h5 *h5 = hu->priv;
3f27e95b	677	unsigned long flags;
7d664fba JH	678	struct sk_buff skb, nskb;
7d664fba JH	679
95c5c220 JH	680	if (h5->sleep != H5_AWAKE) {
	681	const unsigned char wakeup_req[] = { 0x05, 0xfa };
	682
	683	if (h5->sleep == H5_WAKING_UP)
	684	return NULL;
	685
	686	h5->sleep = H5_WAKING_UP;
	687	BT_DBG("Sending wakeup request");
	688
	689	mod_timer(&h5->timer, jiffies + HZ / 100);
	690	return h5_prepare_pkt(hu, HCI_3WIRE_LINK_PKT, wakeup_req, 2);
	691	}
	692
a08b15e6	693	skb = skb_dequeue(&h5->unrel);
4a2fa2b8	694	if (skb) {
618e8bc2	695	nskb = h5_prepare_pkt(hu, hci_skb_pkt_type(skb),
c0a1b73c	696	skb->data, skb->len);
7d664fba JH	697	if (nskb) {
	698	kfree_skb(skb);
	699	return nskb;
	700	}
	701
	702	skb_queue_head(&h5->unrel, skb);
	703	BT_ERR("Could not dequeue pkt because alloc_skb failed");
	704	}
	705
3f27e95b JH	706	spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
3f27e95b JH	707
afdc944c	708	if (h5->unack.qlen >= h5->tx_win)
3f27e95b JH	709	goto unlock;
3f27e95b JH	710
a08b15e6	711	skb = skb_dequeue(&h5->rel);
4a2fa2b8	712	if (skb) {
618e8bc2	713	nskb = h5_prepare_pkt(hu, hci_skb_pkt_type(skb),
c0a1b73c	714	skb->data, skb->len);
3f27e95b JH	715	if (nskb) {
	716	__skb_queue_tail(&h5->unack, skb);
	717	mod_timer(&h5->timer, jiffies + H5_ACK_TIMEOUT);
	718	spin_unlock_irqrestore(&h5->unack.lock, flags);
	719	return nskb;
	720	}
	721
	722	skb_queue_head(&h5->rel, skb);
	723	BT_ERR("Could not dequeue pkt because alloc_skb failed");
	724	}
	725
	726	unlock:
	727	spin_unlock_irqrestore(&h5->unack.lock, flags);
	728
e0482103	729	if (test_bit(H5_TX_ACK_REQ, &h5->flags))
40f10224	730	return h5_prepare_pkt(hu, HCI_3WIRE_ACK_PKT, NULL, 0);
7d664fba	731
7dec65c8 JH	732	return NULL;
	733	}
	734
	735	static int h5_flush(struct hci_uart *hu)
	736	{
7d664fba JH	737	BT_DBG("hu %p", hu);
7d664fba JH	738	return 0;
7dec65c8 JH	739	}
7dec65c8 JH	740
4ee7ef19	741	static const struct hci_uart_proto h5p = {
7dec65c8	742	.id = HCI_UART_3WIRE,
7c40fb8d	743	.name = "Three-wire (H5)",
7dec65c8 JH	744	.open = h5_open,
	745	.close = h5_close,
	746	.recv = h5_recv,
	747	.enqueue = h5_enqueue,
	748	.dequeue = h5_dequeue,
	749	.flush = h5_flush,
	750	};
	751
	752	int __init h5_init(void)
	753	{
01009eec	754	return hci_uart_register_proto(&h5p);
7dec65c8 JH	755	}
	756
	757	int __exit h5_deinit(void)
	758	{
	759	return hci_uart_unregister_proto(&h5p);
	760	}