NFC: nci: Add HCI over NCI protocol support

According to the NCI specification, one can use HCI over NCI
to talk with specific NFCEE. The HCI network is viewed as one
logical NFCEE.
This is needed to support secure element running HCI only
firmwares embedded on an NCI capable chipset, like e.g. the
st21nfcb.
There is some duplication between this piece of code and the
HCI core code, but the latter would need to be abstracted even
more to be able to use NCI as a logical transport for HCP packets.

Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 686 insertions, 0 deletions

diff --git a/net/nfc/nci/hci.c b/net/nfc/nci/hci.c
new file mode 100644
index 000000000000..ecf253942606
--- /dev/null
+++ b/net/nfc/nci/hci.c
@@ -0,0 +1,686 @@
+/*
+ *  The NFC Controller Interface is the communication protocol between an
+ *  NFC Controller (NFCC) and a Device Host (DH).
+ *  This is the HCI over NCI implementation, as specified in the 10.2
+ *  section of the NCI 1.1 specification.
+ *
+ *  Copyright (C) 2014  STMicroelectronics SAS. All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation
+ *
+ *  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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <linux/skbuff.h>
+
+#include "../nfc.h"
+#include <net/nfc/nci.h>
+#include <net/nfc/nci_core.h>
+#include <linux/nfc.h>
+
+struct nci_data {
+	u8              conn_id;
+	u8              pipe;
+	u8              cmd;
+	const u8        *data;
+	u32             data_len;
+} __packed;
+
+struct nci_hci_create_pipe_params {
+	u8 src_gate;
+	u8 dest_host;
+	u8 dest_gate;
+} __packed;
+
+struct nci_hci_create_pipe_resp {
+	u8 src_host;
+	u8 src_gate;
+	u8 dest_host;
+	u8 dest_gate;
+	u8 pipe;
+} __packed;
+
+struct nci_hci_delete_pipe_noti {
+	u8 pipe;
+} __packed;
+
+struct nci_hci_all_pipe_cleared_noti {
+	u8 host;
+} __packed;
+
+struct nci_hcp_message {
+	u8 header;      /* type -cmd,evt,rsp- + instruction */
+	u8 data[];
+} __packed;
+
+struct nci_hcp_packet {
+	u8 header;      /* cbit+pipe */
+	struct nci_hcp_message message;
+} __packed;
+
+#define NCI_HCI_ANY_SET_PARAMETER  0x01
+#define NCI_HCI_ANY_GET_PARAMETER  0x02
+#define NCI_HCI_ANY_CLOSE_PIPE     0x04
+
+#define NCI_HFP_NO_CHAINING        0x80
+
+#define NCI_NFCEE_ID_HCI                0x80
+
+#define NCI_EVT_HOT_PLUG           0x03
+
+#define NCI_HCI_ADMIN_PARAM_SESSION_IDENTITY       0x01
+
+/* HCP headers */
+#define NCI_HCI_HCP_PACKET_HEADER_LEN      1
+#define NCI_HCI_HCP_MESSAGE_HEADER_LEN     1
+#define NCI_HCI_HCP_HEADER_LEN             2
+
+/* HCP types */
+#define NCI_HCI_HCP_COMMAND        0x00
+#define NCI_HCI_HCP_EVENT          0x01
+#define NCI_HCI_HCP_RESPONSE       0x02
+
+#define NCI_HCI_ADM_NOTIFY_PIPE_CREATED     0x12
+#define NCI_HCI_ADM_NOTIFY_PIPE_DELETED     0x13
+#define NCI_HCI_ADM_NOTIFY_ALL_PIPE_CLEARED 0x15
+
+#define NCI_HCI_FRAGMENT           0x7f
+#define NCI_HCP_HEADER(type, instr) ((((type) & 0x03) << 6) |\
+				      ((instr) & 0x3f))
+
+#define NCI_HCP_MSG_GET_TYPE(header) ((header & 0xc0) >> 6)
+#define NCI_HCP_MSG_GET_CMD(header)  (header & 0x3f)
+#define NCI_HCP_MSG_GET_PIPE(header) (header & 0x7f)
+
+/* HCI core */
+static void nci_hci_reset_pipes(struct nci_hci_dev *hdev)
+{
+	int i;
+
+	for (i = 0; i < NCI_HCI_MAX_PIPES; i++) {
+		hdev->pipes[i].gate = NCI_HCI_INVALID_GATE;
+		hdev->pipes[i].host = NCI_HCI_INVALID_HOST;
+	}
+	memset(hdev->gate2pipe, NCI_HCI_INVALID_PIPE, sizeof(hdev->gate2pipe));
+}
+
+static void nci_hci_reset_pipes_per_host(struct nci_dev *ndev, u8 host)
+{
+	int i;
+
+	for (i = 0; i < NCI_HCI_MAX_PIPES; i++) {
+		if (ndev->hci_dev->pipes[i].host == host) {
+			ndev->hci_dev->pipes[i].gate = NCI_HCI_INVALID_GATE;
+			ndev->hci_dev->pipes[i].host = NCI_HCI_INVALID_HOST;
+		}
+	}
+}
+
+/* Fragment HCI data over NCI packet.
+ * NFC Forum NCI 10.2.2 Data Exchange:
+ * The payload of the Data Packets sent on the Logical Connection SHALL be
+ * valid HCP packets, as defined within [ETSI_102622]. Each Data Packet SHALL
+ * contain a single HCP packet. NCI Segmentation and Reassembly SHALL NOT be
+ * applied to Data Messages in either direction. The HCI fragmentation mechanism
+ * is used if required.
+ */
+static int nci_hci_send_data(struct nci_dev *ndev, u8 pipe,
+			     const u8 data_type, const u8 *data,
+			     size_t data_len)
+{
+	struct nci_conn_info    *conn_info;
+	struct sk_buff *skb;
+	int len, i, r;
+	u8 cb = pipe;
+
+	conn_info = ndev->hci_dev->conn_info;
+	if (!conn_info)
+		return -EPROTO;
+
+	skb = nci_skb_alloc(ndev, 2 + conn_info->max_pkt_payload_len +
+			    NCI_DATA_HDR_SIZE, GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	skb_reserve(skb, 2 + NCI_DATA_HDR_SIZE);
+	*skb_push(skb, 1) = data_type;
+
+	i = 0;
+	len = conn_info->max_pkt_payload_len;
+
+	do {
+		/* If last packet add NCI_HFP_NO_CHAINING */
+		if (i + conn_info->max_pkt_payload_len -
+		    (skb->len + 1) >= data_len) {
+			cb |= NCI_HFP_NO_CHAINING;
+			len = data_len - i;
+		} else {
+			len = conn_info->max_pkt_payload_len - skb->len - 1;
+		}
+
+		*skb_push(skb, 1) = cb;
+
+		if (len > 0)
+			memcpy(skb_put(skb, len), data + i, len);
+
+		r = nci_send_data(ndev, conn_info->conn_id, skb);
+		if (r < 0)
+			return r;
+
+		i += len;
+		if (i < data_len) {
+			skb_trim(skb, 0);
+			skb_pull(skb, len);
+		}
+	} while (i < data_len);
+
+	return i;
+}
+
+static void nci_hci_send_data_req(struct nci_dev *ndev, unsigned long opt)
+{
+	struct nci_data *data = (struct nci_data *)opt;
+
+	nci_hci_send_data(ndev, data->pipe, data->cmd,
+			  data->data, data->data_len);
+}
+
+int nci_hci_send_event(struct nci_dev *ndev, u8 gate, u8 event,
+		       const u8 *param, size_t param_len)
+{
+	u8 pipe = ndev->hci_dev->gate2pipe[gate];
+
+	if (pipe == NCI_HCI_INVALID_PIPE)
+		return -EADDRNOTAVAIL;
+
+	return nci_hci_send_data(ndev, pipe,
+			NCI_HCP_HEADER(NCI_HCI_HCP_EVENT, event),
+			param, param_len);
+}
+EXPORT_SYMBOL(nci_hci_send_event);
+
+int nci_hci_send_cmd(struct nci_dev *ndev, u8 gate, u8 cmd,
+		     const u8 *param, size_t param_len,
+		     struct sk_buff **skb)
+{
+	struct nci_conn_info    *conn_info;
+	struct nci_data data;
+	int r;
+	u8 pipe = ndev->hci_dev->gate2pipe[gate];
+
+	if (pipe == NCI_HCI_INVALID_PIPE)
+		return -EADDRNOTAVAIL;
+
+	conn_info = ndev->hci_dev->conn_info;
+	if (!conn_info)
+		return -EPROTO;
+
+	data.conn_id = conn_info->conn_id;
+	data.pipe = pipe;
+	data.cmd = NCI_HCP_HEADER(NCI_HCI_HCP_COMMAND, cmd);
+	data.data = param;
+	data.data_len = param_len;
+
+	r = nci_request(ndev, nci_hci_send_data_req, (unsigned long)&data,
+			msecs_to_jiffies(NCI_DATA_TIMEOUT));
+
+	if (r == NCI_STATUS_OK)
+		*skb = conn_info->rx_skb;
+
+	return r;
+}
+EXPORT_SYMBOL(nci_hci_send_cmd);
+
+static void nci_hci_event_received(struct nci_dev *ndev, u8 pipe,
+				   u8 event, struct sk_buff *skb)
+{
+	if (ndev->ops->hci_event_received)
+		ndev->ops->hci_event_received(ndev, pipe, event, skb);
+}
+
+static void nci_hci_cmd_received(struct nci_dev *ndev, u8 pipe,
+				 u8 cmd, struct sk_buff *skb)
+{
+	u8 gate = ndev->hci_dev->pipes[pipe].gate;
+	u8 status = NCI_HCI_ANY_OK | ~NCI_HCI_FRAGMENT;
+	u8 dest_gate, new_pipe;
+	struct nci_hci_create_pipe_resp *create_info;
+	struct nci_hci_delete_pipe_noti *delete_info;
+	struct nci_hci_all_pipe_cleared_noti *cleared_info;
+
+	pr_debug("from gate %x pipe %x cmd %x\n", gate, pipe, cmd);
+
+	switch (cmd) {
+	case NCI_HCI_ADM_NOTIFY_PIPE_CREATED:
+		if (skb->len != 5) {
+			status = NCI_HCI_ANY_E_NOK;
+			goto exit;
+		}
+		create_info = (struct nci_hci_create_pipe_resp *)skb->data;
+		dest_gate = create_info->dest_gate;
+		new_pipe = create_info->pipe;
+
+		/* Save the new created pipe and bind with local gate,
+		 * the description for skb->data[3] is destination gate id
+		 * but since we received this cmd from host controller, we
+		 * are the destination and it is our local gate
+		 */
+		ndev->hci_dev->gate2pipe[dest_gate] = new_pipe;
+		ndev->hci_dev->pipes[new_pipe].gate = dest_gate;
+		ndev->hci_dev->pipes[new_pipe].host =
+						create_info->src_host;
+		break;
+	case NCI_HCI_ANY_OPEN_PIPE:
+		/* If the pipe is not created report an error */
+		if (gate == NCI_HCI_INVALID_GATE) {
+			status = NCI_HCI_ANY_E_NOK;
+			goto exit;
+		}
+		break;
+	case NCI_HCI_ADM_NOTIFY_PIPE_DELETED:
+		if (skb->len != 1) {
+			status = NCI_HCI_ANY_E_NOK;
+			goto exit;
+		}
+		delete_info = (struct nci_hci_delete_pipe_noti *)skb->data;
+
+		ndev->hci_dev->pipes[delete_info->pipe].gate =
+						NCI_HCI_INVALID_GATE;
+		ndev->hci_dev->pipes[delete_info->pipe].host =
+						NCI_HCI_INVALID_HOST;
+		break;
+	case NCI_HCI_ADM_NOTIFY_ALL_PIPE_CLEARED:
+		if (skb->len != 1) {
+			status = NCI_HCI_ANY_E_NOK;
+			goto exit;
+		}
+
+		cleared_info =
+			(struct nci_hci_all_pipe_cleared_noti *)skb->data;
+		nci_hci_reset_pipes_per_host(ndev, cleared_info->host);
+		break;
+	default:
+		pr_debug("Discarded unknown cmd %x to gate %x\n", cmd, gate);
+		break;
+	}
+
+	if (ndev->ops->hci_cmd_received)
+		ndev->ops->hci_cmd_received(ndev, pipe, cmd, skb);
+
+exit:
+	nci_hci_send_data(ndev, pipe, status, NULL, 0);
+
+	kfree_skb(skb);
+}
+
+static void nci_hci_resp_received(struct nci_dev *ndev, u8 pipe,
+				  u8 result, struct sk_buff *skb)
+{
+	struct nci_conn_info    *conn_info;
+	u8 status = result;
+
+	if (result != NCI_HCI_ANY_OK)
+		goto exit;
+
+	conn_info = ndev->hci_dev->conn_info;
+	if (!conn_info) {
+		status = NCI_STATUS_REJECTED;
+		goto exit;
+	}
+
+	conn_info->rx_skb = skb;
+
+exit:
+	nci_req_complete(ndev, status);
+}
+
+/* Receive hcp message for pipe, with type and cmd.
+ * skb contains optional message data only.
+ */
+static void nci_hci_hcp_message_rx(struct nci_dev *ndev, u8 pipe,
+				   u8 type, u8 instruction, struct sk_buff *skb)
+{
+	switch (type) {
+	case NCI_HCI_HCP_RESPONSE:
+		nci_hci_resp_received(ndev, pipe, instruction, skb);
+		break;
+	case NCI_HCI_HCP_COMMAND:
+		nci_hci_cmd_received(ndev, pipe, instruction, skb);
+		break;
+	case NCI_HCI_HCP_EVENT:
+		nci_hci_event_received(ndev, pipe, instruction, skb);
+		break;
+	default:
+		pr_err("UNKNOWN MSG Type %d, instruction=%d\n",
+		       type, instruction);
+		kfree_skb(skb);
+		break;
+	}
+
+	nci_req_complete(ndev, 0);
+}
+
+static void nci_hci_msg_rx_work(struct work_struct *work)
+{
+	struct nci_hci_dev *hdev =
+		container_of(work, struct nci_hci_dev, msg_rx_work);
+	struct sk_buff *skb;
+	struct nci_hcp_message *message;
+	u8 pipe, type, instruction;
+
+	while ((skb = skb_dequeue(&hdev->msg_rx_queue)) != NULL) {
+		pipe = skb->data[0];
+		skb_pull(skb, NCI_HCI_HCP_PACKET_HEADER_LEN);
+		message = (struct nci_hcp_message *)skb->data;
+		type = NCI_HCP_MSG_GET_TYPE(message->header);
+		instruction = NCI_HCP_MSG_GET_CMD(message->header);
+		skb_pull(skb, NCI_HCI_HCP_MESSAGE_HEADER_LEN);
+
+		nci_hci_hcp_message_rx(hdev->ndev, pipe,
+				       type, instruction, skb);
+	}
+}
+
+void nci_hci_data_received_cb(void *context,
+			      struct sk_buff *skb, int err)
+{
+	struct nci_dev *ndev = (struct nci_dev *)context;
+	struct nci_hcp_packet *packet;
+	u8 pipe, type, instruction;
+	struct sk_buff *hcp_skb;
+	struct sk_buff *frag_skb;
+	int msg_len;
+
+	pr_debug("\n");
+
+	if (err) {
+		nci_req_complete(ndev, err);
+		return;
+	}
+
+	packet = (struct nci_hcp_packet *)skb->data;
+	if ((packet->header & ~NCI_HCI_FRAGMENT) == 0) {
+		skb_queue_tail(&ndev->hci_dev->rx_hcp_frags, skb);
+		return;
+	}
+
+	/* it's the last fragment. Does it need re-aggregation? */
+	if (skb_queue_len(&ndev->hci_dev->rx_hcp_frags)) {
+		pipe = packet->header & NCI_HCI_FRAGMENT;
+		skb_queue_tail(&ndev->hci_dev->rx_hcp_frags, skb);
+
+		msg_len = 0;
+		skb_queue_walk(&ndev->hci_dev->rx_hcp_frags, frag_skb) {
+			msg_len += (frag_skb->len -
+				    NCI_HCI_HCP_PACKET_HEADER_LEN);
+		}
+
+		hcp_skb = nfc_alloc_recv_skb(NCI_HCI_HCP_PACKET_HEADER_LEN +
+					     msg_len, GFP_KERNEL);
+		if (!hcp_skb) {
+			nci_req_complete(ndev, -ENOMEM);
+			return;
+		}
+
+		*skb_put(hcp_skb, NCI_HCI_HCP_PACKET_HEADER_LEN) = pipe;
+
+		skb_queue_walk(&ndev->hci_dev->rx_hcp_frags, frag_skb) {
+		       msg_len = frag_skb->len - NCI_HCI_HCP_PACKET_HEADER_LEN;
+			memcpy(skb_put(hcp_skb, msg_len), frag_skb->data +
+			       NCI_HCI_HCP_PACKET_HEADER_LEN, msg_len);
+		}
+
+		skb_queue_purge(&ndev->hci_dev->rx_hcp_frags);
+	} else {
+		packet->header &= NCI_HCI_FRAGMENT;
+		hcp_skb = skb;
+	}
+
+	/* if this is a response, dispatch immediately to
+	 * unblock waiting cmd context. Otherwise, enqueue to dispatch
+	 * in separate context where handler can also execute command.
+	 */
+	packet = (struct nci_hcp_packet *)hcp_skb->data;
+	type = NCI_HCP_MSG_GET_TYPE(packet->message.header);
+	if (type == NCI_HCI_HCP_RESPONSE) {
+		pipe = packet->header;
+		instruction = NCI_HCP_MSG_GET_CMD(packet->message.header);
+		skb_pull(hcp_skb, NCI_HCI_HCP_PACKET_HEADER_LEN +
+			 NCI_HCI_HCP_MESSAGE_HEADER_LEN);
+		nci_hci_hcp_message_rx(ndev, pipe, type, instruction, hcp_skb);
+	} else {
+		skb_queue_tail(&ndev->hci_dev->msg_rx_queue, hcp_skb);
+		schedule_work(&ndev->hci_dev->msg_rx_work);
+	}
+}
+
+int nci_hci_open_pipe(struct nci_dev *ndev, u8 pipe)
+{
+	struct nci_data data;
+	struct nci_conn_info    *conn_info;
+
+	conn_info = ndev->hci_dev->conn_info;
+	if (!conn_info)
+		return -EPROTO;
+
+	data.conn_id = conn_info->conn_id;
+	data.pipe = pipe;
+	data.cmd = NCI_HCP_HEADER(NCI_HCI_HCP_COMMAND,
+				       NCI_HCI_ANY_OPEN_PIPE);
+	data.data = NULL;
+	data.data_len = 0;
+
+	return nci_request(ndev, nci_hci_send_data_req,
+			(unsigned long)&data,
+			msecs_to_jiffies(NCI_DATA_TIMEOUT));
+}
+EXPORT_SYMBOL(nci_hci_open_pipe);
+
+int nci_hci_set_param(struct nci_dev *ndev, u8 gate, u8 idx,
+		      const u8 *param, size_t param_len)
+{
+	struct nci_conn_info *conn_info;
+	struct nci_data data;
+	int r;
+	u8 *tmp;
+	u8 pipe = ndev->hci_dev->gate2pipe[gate];
+
+	pr_debug("idx=%d to gate %d\n", idx, gate);
+
+	if (pipe == NCI_HCI_INVALID_PIPE)
+		return -EADDRNOTAVAIL;
+
+	conn_info = ndev->hci_dev->conn_info;
+	if (!conn_info)
+		return -EPROTO;
+
+	tmp = kmalloc(1 + param_len, GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	*tmp = idx;
+	memcpy(tmp + 1, param, param_len);
+
+	data.conn_id = conn_info->conn_id;
+	data.pipe = pipe;
+	data.cmd = NCI_HCP_HEADER(NCI_HCI_HCP_COMMAND,
+				       NCI_HCI_ANY_SET_PARAMETER);
+	data.data = tmp;
+	data.data_len = param_len + 1;
+
+	r = nci_request(ndev, nci_hci_send_data_req,
+			(unsigned long)&data,
+			msecs_to_jiffies(NCI_DATA_TIMEOUT));
+
+	kfree(tmp);
+	return r;
+}
+EXPORT_SYMBOL(nci_hci_set_param);
+
+int nci_hci_get_param(struct nci_dev *ndev, u8 gate, u8 idx,
+		      struct sk_buff **skb)
+{
+	struct nci_conn_info    *conn_info;
+	struct nci_data data;
+	int r;
+	u8 pipe = ndev->hci_dev->gate2pipe[gate];
+
+	pr_debug("idx=%d to gate %d\n", idx, gate);
+
+	if (pipe == NCI_HCI_INVALID_PIPE)
+		return -EADDRNOTAVAIL;
+
+	conn_info = ndev->hci_dev->conn_info;
+	if (!conn_info)
+		return -EPROTO;
+
+	data.conn_id = conn_info->conn_id;
+	data.pipe = pipe;
+	data.cmd = NCI_HCP_HEADER(NCI_HCI_HCP_COMMAND,
+				  NCI_HCI_ANY_GET_PARAMETER);
+	data.data = &idx;
+	data.data_len = 1;
+
+	r = nci_request(ndev, nci_hci_send_data_req, (unsigned long)&data,
+			msecs_to_jiffies(NCI_DATA_TIMEOUT));
+
+	if (r == NCI_STATUS_OK)
+		*skb = conn_info->rx_skb;
+
+	return r;
+}
+EXPORT_SYMBOL(nci_hci_get_param);
+
+int nci_hci_connect_gate(struct nci_dev *ndev,
+			 u8 dest_host, u8 dest_gate, u8 pipe)
+{
+	int r;
+
+	if (pipe == NCI_HCI_DO_NOT_OPEN_PIPE)
+		return 0;
+
+	if (ndev->hci_dev->gate2pipe[dest_gate] != NCI_HCI_INVALID_PIPE)
+		return -EADDRINUSE;
+
+	if (pipe != NCI_HCI_INVALID_PIPE)
+		goto open_pipe;
+
+	switch (dest_gate) {
+	case NCI_HCI_LINK_MGMT_GATE:
+		pipe = NCI_HCI_LINK_MGMT_PIPE;
+	break;
+	case NCI_HCI_ADMIN_GATE:
+		pipe = NCI_HCI_ADMIN_PIPE;
+	break;
+	}
+
+open_pipe:
+	r = nci_hci_open_pipe(ndev, pipe);
+	if (r < 0)
+		return r;
+
+	ndev->hci_dev->pipes[pipe].gate = dest_gate;
+	ndev->hci_dev->pipes[pipe].host = dest_host;
+	ndev->hci_dev->gate2pipe[dest_gate] = pipe;
+
+	return 0;
+}
+EXPORT_SYMBOL(nci_hci_connect_gate);
+
+static int nci_hci_dev_connect_gates(struct nci_dev *ndev,
+				     u8 gate_count,
+				     struct nci_hci_gate *gates)
+{
+	int r;
+
+	while (gate_count--) {
+		r = nci_hci_connect_gate(ndev, gates->dest_host,
+					 gates->gate, gates->pipe);
+		if (r < 0)
+			return r;
+		gates++;
+	}
+
+	return 0;
+}
+
+int nci_hci_dev_session_init(struct nci_dev *ndev)
+{
+	struct sk_buff *skb;
+	int r;
+
+	ndev->hci_dev->count_pipes = 0;
+	ndev->hci_dev->expected_pipes = 0;
+
+	nci_hci_reset_pipes(ndev->hci_dev);
+
+	if (ndev->hci_dev->init_data.gates[0].gate != NCI_HCI_ADMIN_GATE)
+		return -EPROTO;
+
+	r = nci_hci_connect_gate(ndev,
+				 ndev->hci_dev->init_data.gates[0].dest_host,
+				 ndev->hci_dev->init_data.gates[0].gate,
+				 ndev->hci_dev->init_data.gates[0].pipe);
+	if (r < 0)
+		goto exit;
+
+	r = nci_hci_get_param(ndev, NCI_HCI_ADMIN_GATE,
+			      NCI_HCI_ADMIN_PARAM_SESSION_IDENTITY, &skb);
+	if (r < 0)
+		goto exit;
+
+	if (skb->len &&
+	    skb->len == strlen(ndev->hci_dev->init_data.session_id) &&
+	    memcmp(ndev->hci_dev->init_data.session_id,
+		   skb->data, skb->len) == 0 &&
+	    ndev->ops->hci_load_session) {
+		/* Restore gate<->pipe table from some proprietary location. */
+		r = ndev->ops->hci_load_session(ndev);
+		if (r < 0)
+			goto exit;
+	} else {
+		r = nci_hci_dev_connect_gates(ndev,
+					      ndev->hci_dev->init_data.gate_count,
+					      ndev->hci_dev->init_data.gates);
+		if (r < 0)
+			goto exit;
+
+		r = nci_hci_set_param(ndev, NCI_HCI_ADMIN_GATE,
+				      NCI_HCI_ADMIN_PARAM_SESSION_IDENTITY,
+				      ndev->hci_dev->init_data.session_id,
+				      strlen(ndev->hci_dev->init_data.session_id));
+	}
+	if (r == 0)
+		goto exit;
+
+exit:
+	kfree_skb(skb);
+
+	return r;
+}
+EXPORT_SYMBOL(nci_hci_dev_session_init);
+
+struct nci_hci_dev *nci_hci_allocate(struct nci_dev *ndev)
+{
+	struct nci_hci_dev *hdev;
+
+	hdev = kzalloc(sizeof(*hdev), GFP_KERNEL);
+	if (!hdev)
+		return NULL;
+
+	skb_queue_head_init(&hdev->rx_hcp_frags);
+	INIT_WORK(&hdev->msg_rx_work, nci_hci_msg_rx_work);
+	skb_queue_head_init(&hdev->msg_rx_queue);
+	hdev->ndev = ndev;
+
+	return hdev;
+}