net/nfc/nci/hci.c - third_party/linux - Git at Google

 /*
  *  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_HCI_ADM_CLEAR_ALL_PIPE 0x14

 #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
 #define NCI_HCI_ADM_CREATE_PIPE			0x10
 #define NCI_HCI_ADM_DELETE_PIPE			0x11

 /* 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)

 static int nci_hci_result_to_errno(u8 result)
 {
 	switch (result) {
 	case NCI_HCI_ANY_OK:
 		return 0;
 	case NCI_HCI_ANY_E_REG_PAR_UNKNOWN:
 		return -EOPNOTSUPP;
 	case NCI_HCI_ANY_E_TIMEOUT:
 		return -ETIME;
 	default:
 		return -1;
 	}
 }

 /* 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;

 	i = 0;
 	skb = nci_skb_alloc(ndev, conn_info->max_pkt_payload_len +
 			    NCI_DATA_HDR_SIZE, GFP_KERNEL);
 	if (!skb)
 		return -ENOMEM;

 	skb_reserve(skb, NCI_DATA_HDR_SIZE + 2);
 	*(u8 *)skb_push(skb, 1) = data_type;

 	do {
 		len = conn_info->max_pkt_payload_len;

 		/* 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;
 		}

 		*(u8 *)skb_push(skb, 1) = cb;

 		if (len > 0)
 			skb_put_data(skb, 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 = nci_skb_alloc(ndev,
 					    conn_info->max_pkt_payload_len +
 					    NCI_DATA_HDR_SIZE, GFP_KERNEL);
 			if (!skb)
 				return -ENOMEM;

 			skb_reserve(skb, NCI_DATA_HDR_SIZE + 1);
 		}
 	} 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_hcp_message *message;
 	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) {
 		message = (struct nci_hcp_message *)conn_info->rx_skb->data;
 		r = nci_hci_result_to_errno(
 			NCI_HCP_MSG_GET_CMD(message->header));
 		skb_pull(conn_info->rx_skb, NCI_HCI_HCP_MESSAGE_HEADER_LEN);

 		if (!r && skb)
 			*skb = conn_info->rx_skb;
 	}

 	return r;
 }
 EXPORT_SYMBOL(nci_hci_send_cmd);

 int nci_hci_clear_all_pipes(struct nci_dev *ndev)
 {
 	int r;

 	r = nci_hci_send_cmd(ndev, NCI_HCI_ADMIN_GATE,
 			     NCI_HCI_ADM_CLEAR_ALL_PIPE, NULL, 0, NULL);
 	if (r < 0)
 		return r;

 	nci_hci_reset_pipes(ndev->hci_dev);
 	return r;
 }
 EXPORT_SYMBOL(nci_hci_clear_all_pipes);

 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;

 	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, NCI_STATUS_OK);
 }

 /* 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, NCI_STATUS_OK);
 }

 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 = NCI_HCP_MSG_GET_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;
 	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 = NCI_HCP_MSG_GET_PIPE(packet->header);
 		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;
 		}

 		*(u8 *)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;
 			skb_put_data(hcp_skb,
 				     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 = NCI_HCP_MSG_GET_PIPE(packet->header);
 		skb_pull(hcp_skb, NCI_HCI_HCP_PACKET_HEADER_LEN);
 		nci_hci_hcp_message_rx(ndev, pipe, type,
 				       NCI_STATUS_OK, 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);

 static u8 nci_hci_create_pipe(struct nci_dev *ndev, u8 dest_host,
 			      u8 dest_gate, int *result)
 {
 	u8 pipe;
 	struct sk_buff *skb;
 	struct nci_hci_create_pipe_params params;
 	struct nci_hci_create_pipe_resp *resp;

 	pr_debug("gate=%d\n", dest_gate);

 	params.src_gate = NCI_HCI_ADMIN_GATE;
 	params.dest_host = dest_host;
 	params.dest_gate = dest_gate;

 	*result = nci_hci_send_cmd(ndev, NCI_HCI_ADMIN_GATE,
 				   NCI_HCI_ADM_CREATE_PIPE,
 				   (u8 *)&params, sizeof(params), &skb);
 	if (*result < 0)
 		return NCI_HCI_INVALID_PIPE;

 	resp = (struct nci_hci_create_pipe_resp *)skb->data;
 	pipe = resp->pipe;
 	kfree_skb(skb);

 	pr_debug("pipe created=%d\n", pipe);

 	return pipe;
 }

 static int nci_hci_delete_pipe(struct nci_dev *ndev, u8 pipe)
 {
 	pr_debug("\n");

 	return nci_hci_send_cmd(ndev, NCI_HCI_ADMIN_GATE,
 				NCI_HCI_ADM_DELETE_PIPE, &pipe, 1, NULL);
 }

 int nci_hci_set_param(struct nci_dev *ndev, u8 gate, u8 idx,
 		      const u8 *param, size_t param_len)
 {
 	struct nci_hcp_message *message;
 	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));
 	if (r == NCI_STATUS_OK) {
 		message = (struct nci_hcp_message *)conn_info->rx_skb->data;
 		r = nci_hci_result_to_errno(
 			NCI_HCP_MSG_GET_CMD(message->header));
 		skb_pull(conn_info->rx_skb, NCI_HCI_HCP_MESSAGE_HEADER_LEN);
 	}

 	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_hcp_message *message;
 	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) {
 		message = (struct nci_hcp_message *)conn_info->rx_skb->data;
 		r = nci_hci_result_to_errno(
 			NCI_HCP_MSG_GET_CMD(message->header));
 		skb_pull(conn_info->rx_skb, NCI_HCI_HCP_MESSAGE_HEADER_LEN);

 		if (!r && skb)
 			*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)
 {
 	bool pipe_created = false;
 	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;
 	default:
 		pipe = nci_hci_create_pipe(ndev, dest_host, dest_gate, &r);
 		if (pipe == NCI_HCI_INVALID_PIPE)
 			return r;
 		pipe_created = true;
 		break;
 	}

 open_pipe:
 	r = nci_hci_open_pipe(ndev, pipe);
 	if (r < 0) {
 		if (pipe_created) {
 			if (nci_hci_delete_pipe(ndev, pipe) < 0) {
 				/* TODO: Cannot clean by deleting pipe...
 				 * -> inconsistent state
 				 */
 			}
 		}
 		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 nci_conn_info    *conn_info;
 	struct sk_buff *skb;
 	int r;

 	ndev->hci_dev->count_pipes = 0;
 	ndev->hci_dev->expected_pipes = 0;

 	conn_info = ndev->hci_dev->conn_info;
 	if (!conn_info)
 		return -EPROTO;

 	conn_info->data_exchange_cb = nci_hci_data_received_cb;
 	conn_info->data_exchange_cb_context = ndev;

 	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)
 		return r;

 	r = nci_hci_get_param(ndev, NCI_HCI_ADMIN_GATE,
 			      NCI_HCI_ADMIN_PARAM_SESSION_IDENTITY, &skb);
 	if (r < 0)
 		return r;

 	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) &&
 	    ndev->ops->hci_load_session) {
 		/* Restore gate<->pipe table from some proprietary location. */
 		r = ndev->ops->hci_load_session(ndev);
 	} else {
 		r = nci_hci_clear_all_pipes(ndev);
 		if (r < 0)
 			goto exit;

 		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));
 	}

 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;
 }
	/*
	* 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_HCI_ADM_CLEAR_ALL_PIPE 0x14

	#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
	#define NCI_HCI_ADM_CREATE_PIPE 0x10
	#define NCI_HCI_ADM_DELETE_PIPE 0x11

	/* 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)

	static int nci_hci_result_to_errno(u8 result)
	{
	switch (result) {
	case NCI_HCI_ANY_OK:
	return 0;
	case NCI_HCI_ANY_E_REG_PAR_UNKNOWN:
	return -EOPNOTSUPP;
	case NCI_HCI_ANY_E_TIMEOUT:
	return -ETIME;
	default:
	return -1;
	}
	}

	/* 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;

	i = 0;
	skb = nci_skb_alloc(ndev, conn_info->max_pkt_payload_len +
	NCI_DATA_HDR_SIZE, GFP_KERNEL);
	if (!skb)
	return -ENOMEM;

	skb_reserve(skb, NCI_DATA_HDR_SIZE + 2);
	(u8 )skb_push(skb, 1) = data_type;

	do {
	len = conn_info->max_pkt_payload_len;

	/* 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;
	}

	(u8 )skb_push(skb, 1) = cb;

	if (len > 0)
	skb_put_data(skb, 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 = nci_skb_alloc(ndev,
	conn_info->max_pkt_payload_len +
	NCI_DATA_HDR_SIZE, GFP_KERNEL);
	if (!skb)
	return -ENOMEM;

	skb_reserve(skb, NCI_DATA_HDR_SIZE + 1);
	}
	} 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_hcp_message *message;
	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) {
	message = (struct nci_hcp_message *)conn_info->rx_skb->data;
	r = nci_hci_result_to_errno(
	NCI_HCP_MSG_GET_CMD(message->header));
	skb_pull(conn_info->rx_skb, NCI_HCI_HCP_MESSAGE_HEADER_LEN);

	if (!r && skb)
	*skb = conn_info->rx_skb;
	}

	return r;
	}
	EXPORT_SYMBOL(nci_hci_send_cmd);

	int nci_hci_clear_all_pipes(struct nci_dev *ndev)
	{
	int r;

	r = nci_hci_send_cmd(ndev, NCI_HCI_ADMIN_GATE,
	NCI_HCI_ADM_CLEAR_ALL_PIPE, NULL, 0, NULL);
	if (r < 0)
	return r;

	nci_hci_reset_pipes(ndev->hci_dev);
	return r;
	}
	EXPORT_SYMBOL(nci_hci_clear_all_pipes);

	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;

	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, NCI_STATUS_OK);
	}

	/* 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, NCI_STATUS_OK);
	}

	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 = NCI_HCP_MSG_GET_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;
	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 = NCI_HCP_MSG_GET_PIPE(packet->header);
	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;
	}

	(u8 )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;
	skb_put_data(hcp_skb,
	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 = NCI_HCP_MSG_GET_PIPE(packet->header);
	skb_pull(hcp_skb, NCI_HCI_HCP_PACKET_HEADER_LEN);
	nci_hci_hcp_message_rx(ndev, pipe, type,
	NCI_STATUS_OK, 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);

	static u8 nci_hci_create_pipe(struct nci_dev *ndev, u8 dest_host,
	u8 dest_gate, int *result)
	{
	u8 pipe;
	struct sk_buff *skb;
	struct nci_hci_create_pipe_params params;
	struct nci_hci_create_pipe_resp *resp;

	pr_debug("gate=%d\n", dest_gate);

	params.src_gate = NCI_HCI_ADMIN_GATE;
	params.dest_host = dest_host;
	params.dest_gate = dest_gate;

	*result = nci_hci_send_cmd(ndev, NCI_HCI_ADMIN_GATE,
	NCI_HCI_ADM_CREATE_PIPE,
	(u8 *)&params, sizeof(params), &skb);
	if (*result < 0)
	return NCI_HCI_INVALID_PIPE;

	resp = (struct nci_hci_create_pipe_resp *)skb->data;
	pipe = resp->pipe;
	kfree_skb(skb);

	pr_debug("pipe created=%d\n", pipe);

	return pipe;
	}

	static int nci_hci_delete_pipe(struct nci_dev *ndev, u8 pipe)
	{
	pr_debug("\n");

	return nci_hci_send_cmd(ndev, NCI_HCI_ADMIN_GATE,
	NCI_HCI_ADM_DELETE_PIPE, &pipe, 1, NULL);
	}

	int nci_hci_set_param(struct nci_dev *ndev, u8 gate, u8 idx,
	const u8 *param, size_t param_len)
	{
	struct nci_hcp_message *message;
	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));
	if (r == NCI_STATUS_OK) {
	message = (struct nci_hcp_message *)conn_info->rx_skb->data;
	r = nci_hci_result_to_errno(
	NCI_HCP_MSG_GET_CMD(message->header));
	skb_pull(conn_info->rx_skb, NCI_HCI_HCP_MESSAGE_HEADER_LEN);
	}

	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_hcp_message *message;
	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) {
	message = (struct nci_hcp_message *)conn_info->rx_skb->data;
	r = nci_hci_result_to_errno(
	NCI_HCP_MSG_GET_CMD(message->header));
	skb_pull(conn_info->rx_skb, NCI_HCI_HCP_MESSAGE_HEADER_LEN);

	if (!r && skb)
	*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)
	{
	bool pipe_created = false;
	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;
	default:
	pipe = nci_hci_create_pipe(ndev, dest_host, dest_gate, &r);
	if (pipe == NCI_HCI_INVALID_PIPE)
	return r;
	pipe_created = true;
	break;
	}

	open_pipe:
	r = nci_hci_open_pipe(ndev, pipe);
	if (r < 0) {
	if (pipe_created) {
	if (nci_hci_delete_pipe(ndev, pipe) < 0) {
	/* TODO: Cannot clean by deleting pipe...
	* -> inconsistent state
	*/
	}
	}
	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 nci_conn_info *conn_info;
	struct sk_buff *skb;
	int r;

	ndev->hci_dev->count_pipes = 0;
	ndev->hci_dev->expected_pipes = 0;

	conn_info = ndev->hci_dev->conn_info;
	if (!conn_info)
	return -EPROTO;

	conn_info->data_exchange_cb = nci_hci_data_received_cb;
	conn_info->data_exchange_cb_context = ndev;

	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)
	return r;

	r = nci_hci_get_param(ndev, NCI_HCI_ADMIN_GATE,
	NCI_HCI_ADMIN_PARAM_SESSION_IDENTITY, &skb);
	if (r < 0)
	return r;

	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) &&
	ndev->ops->hci_load_session) {
	/* Restore gate<->pipe table from some proprietary location. */
	r = ndev->ops->hci_load_session(ndev);
	} else {
	r = nci_hci_clear_all_pipes(ndev);
	if (r < 0)
	goto exit;

	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));
	}

	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;
	}