/*
   * Copyright (C) 2012  Intel Corporation. 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 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, see <http://www.gnu.org/licenses/>.
   */
  
  #define pr_fmt(fmt) "hci: %s: " fmt, __func__
  
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  
  #include <net/nfc/hci.h>
  
  #include "hci.h"
  
  /*
   * Payload is the HCP message data only. Instruction will be prepended.
   * Guarantees that cb will be called upon completion or timeout delay
   * counted from the moment the cmd is sent to the transport.
   */
  int nfc_hci_hcp_message_tx(struct nfc_hci_dev *hdev, u8 pipe,
  			   u8 type, u8 instruction,
  			   const u8 *payload, size_t payload_len,
  			   data_exchange_cb_t cb, void *cb_context,
  			   unsigned long completion_delay)
  {
  	struct nfc_dev *ndev = hdev->ndev;
  	struct hci_msg *cmd;
  	const u8 *ptr = payload;
  	int hci_len, err;
  	bool firstfrag = true;
  
  	cmd = kzalloc(sizeof(struct hci_msg), GFP_KERNEL);
  	if (cmd == NULL)
  		return -ENOMEM;
  
  	INIT_LIST_HEAD(&cmd->msg_l);
  	skb_queue_head_init(&cmd->msg_frags);
  	cmd->wait_response = (type == NFC_HCI_HCP_COMMAND) ? true : false;
  	cmd->cb = cb;
  	cmd->cb_context = cb_context;
  	cmd->completion_delay = completion_delay;
  
  	hci_len = payload_len + 1;
  	while (hci_len > 0) {
  		struct sk_buff *skb;
  		int skb_len, data_link_len;
  		struct hcp_packet *packet;
  
  		if (NFC_HCI_HCP_PACKET_HEADER_LEN + hci_len <=
  		    hdev->max_data_link_payload)
  			data_link_len = hci_len;
  		else
  			data_link_len = hdev->max_data_link_payload -
  					NFC_HCI_HCP_PACKET_HEADER_LEN;
  
  		skb_len = ndev->tx_headroom + NFC_HCI_HCP_PACKET_HEADER_LEN +
  			  data_link_len + ndev->tx_tailroom;
  		hci_len -= data_link_len;
  
  		skb = alloc_skb(skb_len, GFP_KERNEL);
  		if (skb == NULL) {
  			err = -ENOMEM;
  			goto out_skb_err;
  		}
  		skb_reserve(skb, ndev->tx_headroom);
  
  		skb_put(skb, NFC_HCI_HCP_PACKET_HEADER_LEN + data_link_len);
  
  		/* Only the last fragment will have the cb bit set to 1 */
  		packet = (struct hcp_packet *)skb->data;
  		packet->header = pipe;
  		if (firstfrag) {
  			firstfrag = false;
  			packet->message.header = HCP_HEADER(type, instruction);
  			if (ptr) {
  				memcpy(packet->message.data, ptr,
  				       data_link_len - 1);
  				ptr += data_link_len - 1;
  			}
  		} else {
  			memcpy(&packet->message, ptr, data_link_len);
  			ptr += data_link_len;
  		}
  
  		/* This is the last fragment, set the cb bit */
  		if (hci_len == 0)
  			packet->header |= ~NFC_HCI_FRAGMENT;
  
  		skb_queue_tail(&cmd->msg_frags, skb);
  	}
  
  	mutex_lock(&hdev->msg_tx_mutex);
  
  	if (hdev->shutting_down) {
  		err = -ESHUTDOWN;
  		mutex_unlock(&hdev->msg_tx_mutex);
  		goto out_skb_err;
  	}
  
  	list_add_tail(&cmd->msg_l, &hdev->msg_tx_queue);
  	mutex_unlock(&hdev->msg_tx_mutex);
  
  	schedule_work(&hdev->msg_tx_work);
  
  	return 0;
  
  out_skb_err:
  	skb_queue_purge(&cmd->msg_frags);
  	kfree(cmd);
  
  	return err;
  }
  
  u8 nfc_hci_pipe2gate(struct nfc_hci_dev *hdev, u8 pipe)
  {
  	int gate;
  
  	for (gate = 0; gate < NFC_HCI_MAX_GATES; gate++)
  		if (hdev->gate2pipe[gate] == pipe)
  			return gate;
  
  	return 0xff;
  }
  
  /*
   * Receive hcp message for pipe, with type and cmd.
   * skb contains optional message data only.
   */
  void nfc_hci_hcp_message_rx(struct nfc_hci_dev *hdev, u8 pipe, u8 type,
  			    u8 instruction, struct sk_buff *skb)
  {
  	switch (type) {
  	case NFC_HCI_HCP_RESPONSE:
  		nfc_hci_resp_received(hdev, instruction, skb);
  		break;
  	case NFC_HCI_HCP_COMMAND:
  		nfc_hci_cmd_received(hdev, pipe, instruction, skb);
  		break;
  	case NFC_HCI_HCP_EVENT:
  		nfc_hci_event_received(hdev, pipe, instruction, skb);
  		break;
  	default:
  		pr_err("UNKNOWN MSG Type %d, instruction=%d
  ",
  		       type, instruction);
  		kfree_skb(skb);
  		break;
  	}
  }