[mirror_ubuntu-eoan-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;

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

	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, 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;

	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;

	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 JH	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)
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);
	311	h5_link_control(hu, conf_req, 3);
	312	} else if (memcmp(data, conf_rsp, 2) == 0) {
afdc944c	313	if (H5_HDR_LEN(hdr) > 2)
1d3a1e69	314	h5->tx_win = (data[2] & 0x07);
afdc944c	315	BT_DBG("Three-wire init complete. tx_win %u", h5->tx_win);
f674a057	316	h5->state = H5_ACTIVE;
cd1b4425	317	hci_uart_init_ready(hu);
40f10224	318	return;
10122d07 JH	319	} else if (memcmp(data, sleep_req, 2) == 0) {
10122d07 JH	320	BT_DBG("Peer went to sleep");
95c5c220 JH	321	h5->sleep = H5_SLEEPING;
95c5c220 JH	322	return;
10122d07 JH	323	} else if (memcmp(data, woken_req, 2) == 0) {
10122d07 JH	324	BT_DBG("Peer woke up");
95c5c220 JH	325	h5->sleep = H5_AWAKE;
	326	} else if (memcmp(data, wakeup_req, 2) == 0) {
	327	BT_DBG("Peer requested wakeup");
	328	h5_link_control(hu, woken_req, 2);
	329	h5->sleep = H5_AWAKE;
40f10224 JH	330	} else {
	331	BT_DBG("Link Control: 0x%02hhx 0x%02hhx", data[0], data[1]);
	332	return;
	333	}
	334
	335	hci_uart_tx_wakeup(hu);
bc1f35b9 JH	336	}
	337
	338	static void h5_complete_rx_pkt(struct hci_uart *hu)
	339	{
	340	struct h5 *h5 = hu->priv;
43eb12d7	341	const unsigned char *hdr = h5->rx_skb->data;
bc1f35b9	342
43eb12d7	343	if (H5_HDR_RELIABLE(hdr)) {
40f10224	344	h5->tx_ack = (h5->tx_ack + 1) % 8;
e0482103	345	set_bit(H5_TX_ACK_REQ, &h5->flags);
40f10224	346	hci_uart_tx_wakeup(hu);
43eb12d7	347	}
bc1f35b9	348
43eb12d7 JH	349	h5->rx_ack = H5_HDR_ACK(hdr);
	350
	351	h5_pkt_cull(h5);
	352
	353	switch (H5_HDR_PKT_TYPE(hdr)) {
bc1f35b9 JH	354	case HCI_EVENT_PKT:
	355	case HCI_ACLDATA_PKT:
	356	case HCI_SCODATA_PKT:
618e8bc2	357	hci_skb_pkt_type(h5->rx_skb) = H5_HDR_PKT_TYPE(hdr);
bc1f35b9 JH	358
	359	/* Remove Three-wire header */
	360	skb_pull(h5->rx_skb, 4);
	361
e1a26170	362	hci_recv_frame(hu->hdev, h5->rx_skb);
bc1f35b9 JH	363	h5->rx_skb = NULL;
	364
	365	break;
	366
	367	default:
	368	h5_handle_internal_rx(hu);
	369	break;
	370	}
	371
	372	h5_reset_rx(h5);
	373	}
	374
	375	static int h5_rx_crc(struct hci_uart *hu, unsigned char c)
	376	{
bc1f35b9	377	h5_complete_rx_pkt(hu);
bc1f35b9 JH	378
	379	return 0;
	380	}
	381
	382	static int h5_rx_payload(struct hci_uart *hu, unsigned char c)
	383	{
	384	struct h5 *h5 = hu->priv;
	385	const unsigned char *hdr = h5->rx_skb->data;
	386
43eb12d7	387	if (H5_HDR_CRC(hdr)) {
bc1f35b9 JH	388	h5->rx_func = h5_rx_crc;
	389	h5->rx_pending = 2;
	390	} else {
	391	h5_complete_rx_pkt(hu);
bc1f35b9 JH	392	}
	393
	394	return 0;
	395	}
	396
	397	static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c)
	398	{
	399	struct h5 *h5 = hu->priv;
	400	const unsigned char *hdr = h5->rx_skb->data;
	401
40f10224 JH	402	BT_DBG("%s rx: seq %u ack %u crc %u rel %u type %u len %u",
	403	hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
	404	H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
	405	H5_HDR_LEN(hdr));
	406
bc1f35b9 JH	407	if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) {
	408	BT_ERR("Invalid header checksum");
	409	h5_reset_rx(h5);
	410	return 0;
	411	}
	412
40f10224	413	if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_ack) {
43eb12d7	414	BT_ERR("Out-of-order packet arrived (%u != %u)",
40f10224	415	H5_HDR_SEQ(hdr), h5->tx_ack);
43eb12d7 JH	416	h5_reset_rx(h5);
	417	return 0;
	418	}
	419
f674a057 JH	420	if (h5->state != H5_ACTIVE &&
	421	H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT) {
	422	BT_ERR("Non-link packet received in non-active state");
	423	h5_reset_rx(h5);
48439d50	424	return 0;
f674a057 JH	425	}
f674a057 JH	426
bc1f35b9	427	h5->rx_func = h5_rx_payload;
43eb12d7	428	h5->rx_pending = H5_HDR_LEN(hdr);
bc1f35b9 JH	429
	430	return 0;
	431	}
	432
	433	static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c)
	434	{
	435	struct h5 *h5 = hu->priv;
	436
bc1f35b9 JH	437	if (c == SLIP_DELIMITER)
	438	return 1;
	439
	440	h5->rx_func = h5_rx_3wire_hdr;
	441	h5->rx_pending = 4;
	442
	443	h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC);
	444	if (!h5->rx_skb) {
	445	BT_ERR("Can't allocate mem for new packet");
	446	h5_reset_rx(h5);
	447	return -ENOMEM;
	448	}
	449
4a2fa2b8	450	h5->rx_skb->dev = (void *)hu->hdev;
bc1f35b9 JH	451
	452	return 0;
	453	}
	454
	455	static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c)
	456	{
	457	struct h5 *h5 = hu->priv;
	458
bc1f35b9 JH	459	if (c == SLIP_DELIMITER)
	460	h5->rx_func = h5_rx_pkt_start;
	461
	462	return 1;
	463	}
	464
	465	static void h5_unslip_one_byte(struct h5 *h5, unsigned char c)
	466	{
	467	const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC;
	468	const u8 *byte = &c;
	469
e0482103 JH	470	if (!test_bit(H5_RX_ESC, &h5->flags) && c == SLIP_ESC) {
e0482103 JH	471	set_bit(H5_RX_ESC, &h5->flags);
bc1f35b9 JH	472	return;
	473	}
	474
e0482103	475	if (test_and_clear_bit(H5_RX_ESC, &h5->flags)) {
bc1f35b9 JH	476	switch (c) {
	477	case SLIP_ESC_DELIM:
	478	byte = &delim;
	479	break;
	480	case SLIP_ESC_ESC:
	481	byte = &esc;
	482	break;
	483	default:
	484	BT_ERR("Invalid esc byte 0x%02hhx", c);
	485	h5_reset_rx(h5);
	486	return;
	487	}
bc1f35b9 JH	488	}
	489
	490	memcpy(skb_put(h5->rx_skb, 1), byte, 1);
	491	h5->rx_pending--;
	492
255a68e0	493	BT_DBG("unsliped 0x%02hhx, rx_pending %zu", *byte, h5->rx_pending);
bc1f35b9 JH	494	}
	495
	496	static void h5_reset_rx(struct h5 *h5)
	497	{
	498	if (h5->rx_skb) {
	499	kfree_skb(h5->rx_skb);
	500	h5->rx_skb = NULL;
	501	}
	502
	503	h5->rx_func = h5_rx_delimiter;
	504	h5->rx_pending = 0;
e0482103	505	clear_bit(H5_RX_ESC, &h5->flags);
bc1f35b9 JH	506	}
bc1f35b9 JH	507
9d1c40eb	508	static int h5_recv(struct hci_uart hu, const void data, int count)
7dec65c8	509	{
bc1f35b9	510	struct h5 *h5 = hu->priv;
9d1c40eb	511	const unsigned char *ptr = data;
bc1f35b9	512
255a68e0 JH	513	BT_DBG("%s pending %zu count %d", hu->hdev->name, h5->rx_pending,
255a68e0 JH	514	count);
bc1f35b9 JH	515
	516	while (count > 0) {
	517	int processed;
	518
	519	if (h5->rx_pending > 0) {
	520	if (*ptr == SLIP_DELIMITER) {
	521	BT_ERR("Too short H5 packet");
	522	h5_reset_rx(h5);
	523	continue;
	524	}
	525
	526	h5_unslip_one_byte(h5, *ptr);
	527
	528	ptr++; count--;
	529	continue;
	530	}
	531
	532	processed = h5->rx_func(hu, *ptr);
	533	if (processed < 0)
	534	return processed;
	535
	536	ptr += processed;
	537	count -= processed;
	538	}
	539
	540	return 0;
7dec65c8 JH	541	}
	542
	543	static int h5_enqueue(struct hci_uart hu, struct sk_buff skb)
	544	{
7d664fba JH	545	struct h5 *h5 = hu->priv;
	546
	547	if (skb->len > 0xfff) {
	548	BT_ERR("Packet too long (%u bytes)", skb->len);
	549	kfree_skb(skb);
	550	return 0;
	551	}
	552
f674a057 JH	553	if (h5->state != H5_ACTIVE) {
	554	BT_ERR("Ignoring HCI data in non-active state");
	555	kfree_skb(skb);
	556	return 0;
	557	}
	558
618e8bc2	559	switch (hci_skb_pkt_type(skb)) {
7d664fba JH	560	case HCI_ACLDATA_PKT:
	561	case HCI_COMMAND_PKT:
	562	skb_queue_tail(&h5->rel, skb);
	563	break;
	564
	565	case HCI_SCODATA_PKT:
	566	skb_queue_tail(&h5->unrel, skb);
	567	break;
	568
	569	default:
618e8bc2	570	BT_ERR("Unknown packet type %u", hci_skb_pkt_type(skb));
7d664fba JH	571	kfree_skb(skb);
	572	break;
	573	}
	574
	575	return 0;
	576	}
	577
c0a1b73c JH	578	static void h5_slip_delim(struct sk_buff *skb)
	579	{
	580	const char delim = SLIP_DELIMITER;
	581
	582	memcpy(skb_put(skb, 1), &delim, 1);
	583	}
	584
	585	static void h5_slip_one_byte(struct sk_buff *skb, u8 c)
	586	{
	587	const char esc_delim[2] = { SLIP_ESC, SLIP_ESC_DELIM };
	588	const char esc_esc[2] = { SLIP_ESC, SLIP_ESC_ESC };
	589
	590	switch (c) {
	591	case SLIP_DELIMITER:
	592	memcpy(skb_put(skb, 2), &esc_delim, 2);
	593	break;
	594	case SLIP_ESC:
	595	memcpy(skb_put(skb, 2), &esc_esc, 2);
	596	break;
	597	default:
	598	memcpy(skb_put(skb, 1), &c, 1);
	599	}
	600	}
	601
c826ed09 JH	602	static bool valid_packet_type(u8 type)
	603	{
	604	switch (type) {
	605	case HCI_ACLDATA_PKT:
	606	case HCI_COMMAND_PKT:
	607	case HCI_SCODATA_PKT:
	608	case HCI_3WIRE_LINK_PKT:
	609	case HCI_3WIRE_ACK_PKT:
	610	return true;
	611	default:
	612	return false;
	613	}
	614	}
	615
	616	static struct sk_buff h5_prepare_pkt(struct hci_uart hu, u8 pkt_type,
	617	const u8 *data, size_t len)
7d664fba	618	{
40f10224	619	struct h5 *h5 = hu->priv;
c0a1b73c JH	620	struct sk_buff *nskb;
	621	u8 hdr[4];
	622	int i;
	623
c826ed09 JH	624	if (!valid_packet_type(pkt_type)) {
	625	BT_ERR("Unknown packet type %u", pkt_type);
	626	return NULL;
	627	}
	628
c0a1b73c JH	629	/*
	630	* Max len of packet: (original len + 4 (H5 hdr) + 2 (crc)) * 2
	631	* (because bytes 0xc0 and 0xdb are escaped, worst case is when
	632	* the packet is all made of 0xc0 and 0xdb) + 2 (0xc0
	633	* delimiters at start and end).
	634	*/
	635	nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
	636	if (!nskb)
	637	return NULL;
	638
618e8bc2	639	hci_skb_pkt_type(nskb) = pkt_type;
c0a1b73c JH	640
	641	h5_slip_delim(nskb);
	642
40f10224	643	hdr[0] = h5->tx_ack << 3;
e0482103	644	clear_bit(H5_TX_ACK_REQ, &h5->flags);
c0a1b73c	645
c826ed09 JH	646	/* Reliable packet? */
c826ed09 JH	647	if (pkt_type == HCI_ACLDATA_PKT \|\| pkt_type == HCI_COMMAND_PKT) {
c0a1b73c	648	hdr[0] \|= 1 << 7;
43eb12d7 JH	649	hdr[0] \|= h5->tx_seq;
43eb12d7 JH	650	h5->tx_seq = (h5->tx_seq + 1) % 8;
c0a1b73c JH	651	}
	652
	653	hdr[1] = pkt_type \| ((len & 0x0f) << 4);
	654	hdr[2] = len >> 4;
	655	hdr[3] = ~((hdr[0] + hdr[1] + hdr[2]) & 0xff);
	656
40f10224 JH	657	BT_DBG("%s tx: seq %u ack %u crc %u rel %u type %u len %u",
	658	hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
	659	H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
	660	H5_HDR_LEN(hdr));
	661
c0a1b73c JH	662	for (i = 0; i < 4; i++)
	663	h5_slip_one_byte(nskb, hdr[i]);
	664
	665	for (i = 0; i < len; i++)
	666	h5_slip_one_byte(nskb, data[i]);
	667
	668	h5_slip_delim(nskb);
	669
	670	return nskb;
	671	}
	672
7dec65c8 JH	673	static struct sk_buff h5_dequeue(struct hci_uart hu)
7dec65c8 JH	674	{
7d664fba	675	struct h5 *h5 = hu->priv;
3f27e95b	676	unsigned long flags;
7d664fba JH	677	struct sk_buff skb, nskb;
7d664fba JH	678
95c5c220 JH	679	if (h5->sleep != H5_AWAKE) {
	680	const unsigned char wakeup_req[] = { 0x05, 0xfa };
	681
	682	if (h5->sleep == H5_WAKING_UP)
	683	return NULL;
	684
	685	h5->sleep = H5_WAKING_UP;
	686	BT_DBG("Sending wakeup request");
	687
	688	mod_timer(&h5->timer, jiffies + HZ / 100);
	689	return h5_prepare_pkt(hu, HCI_3WIRE_LINK_PKT, wakeup_req, 2);
	690	}
	691
a08b15e6	692	skb = skb_dequeue(&h5->unrel);
4a2fa2b8	693	if (skb) {
618e8bc2	694	nskb = h5_prepare_pkt(hu, hci_skb_pkt_type(skb),
c0a1b73c	695	skb->data, skb->len);
7d664fba JH	696	if (nskb) {
	697	kfree_skb(skb);
	698	return nskb;
	699	}
	700
	701	skb_queue_head(&h5->unrel, skb);
	702	BT_ERR("Could not dequeue pkt because alloc_skb failed");
	703	}
	704
3f27e95b JH	705	spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
3f27e95b JH	706
afdc944c	707	if (h5->unack.qlen >= h5->tx_win)
3f27e95b JH	708	goto unlock;
3f27e95b JH	709
a08b15e6	710	skb = skb_dequeue(&h5->rel);
4a2fa2b8	711	if (skb) {
618e8bc2	712	nskb = h5_prepare_pkt(hu, hci_skb_pkt_type(skb),
c0a1b73c	713	skb->data, skb->len);
3f27e95b JH	714	if (nskb) {
	715	__skb_queue_tail(&h5->unack, skb);
	716	mod_timer(&h5->timer, jiffies + H5_ACK_TIMEOUT);
	717	spin_unlock_irqrestore(&h5->unack.lock, flags);
	718	return nskb;
	719	}
	720
	721	skb_queue_head(&h5->rel, skb);
	722	BT_ERR("Could not dequeue pkt because alloc_skb failed");
	723	}
	724
	725	unlock:
	726	spin_unlock_irqrestore(&h5->unack.lock, flags);
	727
e0482103	728	if (test_bit(H5_TX_ACK_REQ, &h5->flags))
40f10224	729	return h5_prepare_pkt(hu, HCI_3WIRE_ACK_PKT, NULL, 0);
7d664fba	730
7dec65c8 JH	731	return NULL;
	732	}
	733
	734	static int h5_flush(struct hci_uart *hu)
	735	{
7d664fba JH	736	BT_DBG("hu %p", hu);
7d664fba JH	737	return 0;
7dec65c8 JH	738	}
7dec65c8 JH	739
4ee7ef19	740	static const struct hci_uart_proto h5p = {
7dec65c8	741	.id = HCI_UART_3WIRE,
7c40fb8d	742	.name = "Three-wire (H5)",
7dec65c8 JH	743	.open = h5_open,
	744	.close = h5_close,
	745	.recv = h5_recv,
	746	.enqueue = h5_enqueue,
	747	.dequeue = h5_dequeue,
	748	.flush = h5_flush,
	749	};
	750
	751	int __init h5_init(void)
	752	{
01009eec	753	return hci_uart_register_proto(&h5p);
7dec65c8 JH	754	}
	755
	756	int __exit h5_deinit(void)
	757	{
	758	return hci_uart_unregister_proto(&h5p);
	759	}