v4.19.13 snapshot.
diff --git a/drivers/bluetooth/hci_h4.c b/drivers/bluetooth/hci_h4.c
new file mode 100644
index 0000000..fb97a3b
--- /dev/null
+++ b/drivers/bluetooth/hci_h4.c
@@ -0,0 +1,286 @@
+/*
+ *
+ *  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>
+ *
+ *
+ *  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/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 <asm/unaligned.h>
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.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(sizeof(*h4), GFP_KERNEL);
+	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;
+
+	hu->priv = NULL;
+
+	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 transmittion (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 },
+};
+
+/* Recv data */
+static int h4_recv(struct hci_uart *hu, const void *data, int count)
+{
+	struct h4_struct *h4 = hu->priv;
+
+	if (!test_bit(HCI_UART_REGISTERED, &hu->flags))
+		return -EUNATCH;
+
+	h4->rx_skb = h4_recv_buf(hu->hdev, 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_dev *hdev, struct sk_buff *skb,
+			    const unsigned char *buffer, int count,
+			    const struct h4_recv_pkt *pkts, int pkts_count)
+{
+	struct hci_uart *hu = hci_get_drvdata(hdev);
+	u8 alignment = hu->alignment ? hu->alignment : 1;
+
+	while (count) {
+		int i, len;
+
+		/* remove padding bytes from buffer */
+		for (; hu->padding && count > 0; hu->padding--) {
+			count--;
+			buffer++;
+		}
+		if (!count)
+			break;
+
+		if (!skb) {
+			for (i = 0; i < pkts_count; i++) {
+				if (buffer[0] != (&pkts[i])->type)
+					continue;
+
+				skb = bt_skb_alloc((&pkts[i])->maxlen,
+						   GFP_ATOMIC);
+				if (!skb)
+					return ERR_PTR(-ENOMEM);
+
+				hci_skb_pkt_type(skb) = (&pkts[i])->type;
+				hci_skb_expect(skb) = (&pkts[i])->hlen;
+				break;
+			}
+
+			/* Check for invalid packet type */
+			if (!skb)
+				return ERR_PTR(-EILSEQ);
+
+			count -= 1;
+			buffer += 1;
+		}
+
+		len = min_t(uint, hci_skb_expect(skb) - skb->len, count);
+		skb_put_data(skb, buffer, len);
+
+		count -= len;
+		buffer += len;
+
+		/* Check for partial packet */
+		if (skb->len < hci_skb_expect(skb))
+			continue;
+
+		for (i = 0; i < pkts_count; i++) {
+			if (hci_skb_pkt_type(skb) == (&pkts[i])->type)
+				break;
+		}
+
+		if (i >= pkts_count) {
+			kfree_skb(skb);
+			return ERR_PTR(-EILSEQ);
+		}
+
+		if (skb->len == (&pkts[i])->hlen) {
+			u16 dlen;
+
+			switch ((&pkts[i])->lsize) {
+			case 0:
+				/* No variable data length */
+				dlen = 0;
+				break;
+			case 1:
+				/* Single octet variable length */
+				dlen = skb->data[(&pkts[i])->loff];
+				hci_skb_expect(skb) += dlen;
+
+				if (skb_tailroom(skb) < dlen) {
+					kfree_skb(skb);
+					return ERR_PTR(-EMSGSIZE);
+				}
+				break;
+			case 2:
+				/* Double octet variable length */
+				dlen = get_unaligned_le16(skb->data +
+							  (&pkts[i])->loff);
+				hci_skb_expect(skb) += dlen;
+
+				if (skb_tailroom(skb) < dlen) {
+					kfree_skb(skb);
+					return ERR_PTR(-EMSGSIZE);
+				}
+				break;
+			default:
+				/* Unsupported variable length */
+				kfree_skb(skb);
+				return ERR_PTR(-EILSEQ);
+			}
+
+			if (!dlen) {
+				hu->padding = (skb->len - 1) % alignment;
+				hu->padding = (alignment - hu->padding) % alignment;
+
+				/* No more data, complete frame */
+				(&pkts[i])->recv(hdev, skb);
+				skb = NULL;
+			}
+		} else {
+			hu->padding = (skb->len - 1) % alignment;
+			hu->padding = (alignment - hu->padding) % alignment;
+
+			/* Complete frame */
+			(&pkts[i])->recv(hdev, skb);
+			skb = NULL;
+		}
+	}
+
+	return skb;
+}
+EXPORT_SYMBOL_GPL(h4_recv_buf);