// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 *  Bluetooth HCI UART driver
 *
 *  Copyright (C) 2000-2001  Qualcomm Incorporated
 *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
 *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
 */

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/poll.h>

#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/signal.h>
#include <linux/ioctl.h>
#include <linux/skbuff.h>
#include <linux/unaligned.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include <net/bluetooth/hci_h4.h>

#include "hci_uart.h"

struct h4_struct {
	struct sk_buff *rx_skb;
	struct sk_buff_head txq;
};

/* Initialize protocol */
static int h4_open(struct hci_uart *hu)
{
	struct h4_struct *h4;

	BT_DBG("hu %p", hu);

	h4 = kzalloc_obj(*h4);
	if (!h4)
		return -ENOMEM;

	skb_queue_head_init(&h4->txq);

	hu->priv = h4;
	return 0;
}

/* Flush protocol data */
static int h4_flush(struct hci_uart *hu)
{
	struct h4_struct *h4 = hu->priv;

	BT_DBG("hu %p", hu);

	skb_queue_purge(&h4->txq);

	return 0;
}

/* Close protocol */
static int h4_close(struct hci_uart *hu)
{
	struct h4_struct *h4 = hu->priv;

	BT_DBG("hu %p", hu);

	skb_queue_purge(&h4->txq);

	kfree_skb(h4->rx_skb);

	hu->priv = NULL;
	kfree(h4);

	return 0;
}

/* Enqueue frame for transmission (padding, crc, etc) */
static int h4_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
	struct h4_struct *h4 = hu->priv;

	BT_DBG("hu %p skb %p", hu, skb);

	/* Prepend skb with frame type */
	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
	skb_queue_tail(&h4->txq, skb);

	return 0;
}

static const struct h4_recv_pkt h4_recv_pkts[] = {
	{ H4_RECV_ACL,   .recv = hci_recv_frame },
	{ H4_RECV_SCO,   .recv = hci_recv_frame },
	{ H4_RECV_EVENT, .recv = hci_recv_frame },
	{ H4_RECV_ISO,   .recv = hci_recv_frame },
};

/* Recv data */
static int h4_recv(struct hci_uart *hu, const void *data, int count)
{
	struct h4_struct *h4 = hu->priv;

	if (!h4)
		return -ENODEV;

	h4->rx_skb = h4_recv_skb(hu->hdev, &hu->alignment, &hu->padding,
				 h4->rx_skb, data, count, h4_recv_pkts,
				 ARRAY_SIZE(h4_recv_pkts));
	if (IS_ERR(h4->rx_skb)) {
		int err = PTR_ERR(h4->rx_skb);
		bt_dev_err(hu->hdev, "Frame reassembly failed (%d)", err);
		h4->rx_skb = NULL;
		return err;
	}

	return count;
}

static struct sk_buff *h4_dequeue(struct hci_uart *hu)
{
	struct h4_struct *h4 = hu->priv;
	return skb_dequeue(&h4->txq);
}

static const struct hci_uart_proto h4p = {
	.id		= HCI_UART_H4,
	.name		= "H4",
	.open		= h4_open,
	.close		= h4_close,
	.recv		= h4_recv,
	.enqueue	= h4_enqueue,
	.dequeue	= h4_dequeue,
	.flush		= h4_flush,
};

int __init h4_init(void)
{
	return hci_uart_register_proto(&h4p);
}

int __exit h4_deinit(void)
{
	return hci_uart_unregister_proto(&h4p);
}

struct sk_buff *h4_recv_buf(struct hci_uart *hu, struct sk_buff *skb,
			    const unsigned char *buffer, int count,
			    const struct h4_recv_pkt *pkts, int pkts_count)
{
	return h4_recv_skb(hu->hdev, &hu->alignment, &hu->padding, skb, buffer,
			   count, pkts, pkts_count);
}
EXPORT_SYMBOL_GPL(h4_recv_buf);