net/nfc/hci/hcp.c

   1 /*
   2  * Copyright (C) 2012  Intel Corporation. All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the
  16  * Free Software Foundation, Inc.,
  17  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18  */
  19
  20 #define pr_fmt(fmt) "hci: %s: " fmt, __func__
  21
  22 #include <linux/init.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25
  26 #include <net/nfc/hci.h>
  27
  28 #include "hci.h"
  29
  30 /*
  31  * Payload is the HCP message data only. Instruction will be prepended.
  32  * Guarantees that cb will be called upon completion or timeout delay
  33  * counted from the moment the cmd is sent to the transport.
  34  */
  35 int nfc_hci_hcp_message_tx(struct nfc_hci_dev *hdev, u8 pipe,
  36                            u8 type, u8 instruction,
  37                            const u8 *payload, size_t payload_len,
  38                            data_exchange_cb_t cb, void *cb_context,
  39                            unsigned long completion_delay)
  40 {
  41         struct nfc_dev *ndev = hdev->ndev;
  42         struct hci_msg *cmd;
  43         const u8 *ptr = payload;
  44         int hci_len, err;
  45         bool firstfrag = true;
  46
  47         cmd = kzalloc(sizeof(struct hci_msg), GFP_KERNEL);
  48         if (cmd == NULL)
  49                 return -ENOMEM;
  50
  51         INIT_LIST_HEAD(&cmd->msg_l);
  52         skb_queue_head_init(&cmd->msg_frags);
  53         cmd->wait_response = (type == NFC_HCI_HCP_COMMAND) ? true : false;
  54         cmd->cb = cb;
  55         cmd->cb_context = cb_context;
  56         cmd->completion_delay = completion_delay;
  57
  58         hci_len = payload_len + 1;
  59         while (hci_len > 0) {
  60                 struct sk_buff *skb;
  61                 int skb_len, data_link_len;
  62                 struct hcp_packet *packet;
  63
  64                 if (NFC_HCI_HCP_PACKET_HEADER_LEN + hci_len <=
  65                     hdev->max_data_link_payload)
  66                         data_link_len = hci_len;
  67                 else
  68                         data_link_len = hdev->max_data_link_payload -
  69                                         NFC_HCI_HCP_PACKET_HEADER_LEN;
  70
  71                 skb_len = ndev->tx_headroom + NFC_HCI_HCP_PACKET_HEADER_LEN +
  72                           data_link_len + ndev->tx_tailroom;
  73                 hci_len -= data_link_len;
  74
  75                 skb = alloc_skb(skb_len, GFP_KERNEL);
  76                 if (skb == NULL) {
  77                         err = -ENOMEM;
  78                         goto out_skb_err;
  79                 }
  80                 skb_reserve(skb, ndev->tx_headroom);
  81
  82                 skb_put(skb, NFC_HCI_HCP_PACKET_HEADER_LEN + data_link_len);
  83
  84                 /* Only the last fragment will have the cb bit set to 1 */
  85                 packet = (struct hcp_packet *)skb->data;
  86                 packet->header = pipe;
  87                 if (firstfrag) {
  88                         firstfrag = false;
  89                         packet->message.header = HCP_HEADER(type, instruction);
  90                         if (ptr) {
  91                                 memcpy(packet->message.data, ptr,
  92                                        data_link_len - 1);
  93                                 ptr += data_link_len - 1;
  94                         }
  95                 } else {
  96                         memcpy(&packet->message, ptr, data_link_len);
  97                         ptr += data_link_len;
  98                 }
  99
 100                 /* This is the last fragment, set the cb bit */
 101                 if (hci_len == 0)
 102                         packet->header |= ~NFC_HCI_FRAGMENT;
 103
 104                 skb_queue_tail(&cmd->msg_frags, skb);
 105         }
 106
 107         mutex_lock(&hdev->msg_tx_mutex);
 108
 109         if (hdev->shutting_down) {
 110                 err = -ESHUTDOWN;
 111                 mutex_unlock(&hdev->msg_tx_mutex);
 112                 goto out_skb_err;
 113         }
 114
 115         list_add_tail(&cmd->msg_l, &hdev->msg_tx_queue);
 116         mutex_unlock(&hdev->msg_tx_mutex);
 117
 118         schedule_work(&hdev->msg_tx_work);
 119
 120         return 0;
 121
 122 out_skb_err:
 123         skb_queue_purge(&cmd->msg_frags);
 124         kfree(cmd);
 125
 126         return err;
 127 }
 128
 129 u8 nfc_hci_pipe2gate(struct nfc_hci_dev *hdev, u8 pipe)
 130 {
 131         int gate;
 132
 133         for (gate = 0; gate < NFC_HCI_MAX_GATES; gate++)
 134                 if (hdev->gate2pipe[gate] == pipe)
 135                         return gate;
 136
 137         return 0xff;
 138 }
 139
 140 /*
 141  * Receive hcp message for pipe, with type and cmd.
 142  * skb contains optional message data only.
 143  */
 144 void nfc_hci_hcp_message_rx(struct nfc_hci_dev *hdev, u8 pipe, u8 type,
 145                             u8 instruction, struct sk_buff *skb)
 146 {
 147         switch (type) {
 148         case NFC_HCI_HCP_RESPONSE:
 149                 nfc_hci_resp_received(hdev, instruction, skb);
 150                 break;
 151         case NFC_HCI_HCP_COMMAND:
 152                 nfc_hci_cmd_received(hdev, pipe, instruction, skb);
 153                 break;
 154         case NFC_HCI_HCP_EVENT:
 155                 nfc_hci_event_received(hdev, pipe, instruction, skb);
 156                 break;
 157         default:
 158                 pr_err("UNKNOWN MSG Type %d, instruction=%d\n",
 159                        type, instruction);
 160                 kfree_skb(skb);
 161                 break;
 162         }
 163 }