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, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #define pr_fmt(fmt) "hci: %s: " fmt, __func__
  19
  20 #include <linux/init.h>
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23
  24 #include <net/nfc/hci.h>
  25
  26 #include "hci.h"
  27
  28 /*
  29  * Payload is the HCP message data only. Instruction will be prepended.
  30  * Guarantees that cb will be called upon completion or timeout delay
  31  * counted from the moment the cmd is sent to the transport.
  32  */
  33 int nfc_hci_hcp_message_tx(struct nfc_hci_dev *hdev, u8 pipe,
  34                            u8 type, u8 instruction,
  35                            const u8 *payload, size_t payload_len,
  36                            data_exchange_cb_t cb, void *cb_context,
  37                            unsigned long completion_delay)
  38 {
  39         struct nfc_dev *ndev = hdev->ndev;
  40         struct hci_msg *cmd;
  41         const u8 *ptr = payload;
  42         int hci_len, err;
  43         bool firstfrag = true;
  44
  45         cmd = kzalloc(sizeof(struct hci_msg), GFP_KERNEL);
  46         if (cmd == NULL)
  47                 return -ENOMEM;
  48
  49         INIT_LIST_HEAD(&cmd->msg_l);
  50         skb_queue_head_init(&cmd->msg_frags);
  51         cmd->wait_response = (type == NFC_HCI_HCP_COMMAND) ? true : false;
  52         cmd->cb = cb;
  53         cmd->cb_context = cb_context;
  54         cmd->completion_delay = completion_delay;
  55
  56         hci_len = payload_len + 1;
  57         while (hci_len > 0) {
  58                 struct sk_buff *skb;
  59                 int skb_len, data_link_len;
  60                 struct hcp_packet *packet;
  61
  62                 if (NFC_HCI_HCP_PACKET_HEADER_LEN + hci_len <=
  63                     hdev->max_data_link_payload)
  64                         data_link_len = hci_len;
  65                 else
  66                         data_link_len = hdev->max_data_link_payload -
  67                                         NFC_HCI_HCP_PACKET_HEADER_LEN;
  68
  69                 skb_len = ndev->tx_headroom + NFC_HCI_HCP_PACKET_HEADER_LEN +
  70                           data_link_len + ndev->tx_tailroom;
  71                 hci_len -= data_link_len;
  72
  73                 skb = alloc_skb(skb_len, GFP_KERNEL);
  74                 if (skb == NULL) {
  75                         err = -ENOMEM;
  76                         goto out_skb_err;
  77                 }
  78                 skb_reserve(skb, ndev->tx_headroom);
  79
  80                 skb_put(skb, NFC_HCI_HCP_PACKET_HEADER_LEN + data_link_len);
  81
  82                 /* Only the last fragment will have the cb bit set to 1 */
  83                 packet = (struct hcp_packet *)skb->data;
  84                 packet->header = pipe;
  85                 if (firstfrag) {
  86                         firstfrag = false;
  87                         packet->message.header = HCP_HEADER(type, instruction);
  88                         if (ptr) {
  89                                 memcpy(packet->message.data, ptr,
  90                                        data_link_len - 1);
  91                                 ptr += data_link_len - 1;
  92                         }
  93                 } else {
  94                         memcpy(&packet->message, ptr, data_link_len);
  95                         ptr += data_link_len;
  96                 }
  97
  98                 /* This is the last fragment, set the cb bit */
  99                 if (hci_len == 0)
 100                         packet->header |= ~NFC_HCI_FRAGMENT;
 101
 102                 skb_queue_tail(&cmd->msg_frags, skb);
 103         }
 104
 105         mutex_lock(&hdev->msg_tx_mutex);
 106
 107         if (hdev->shutting_down) {
 108                 err = -ESHUTDOWN;
 109                 mutex_unlock(&hdev->msg_tx_mutex);
 110                 goto out_skb_err;
 111         }
 112
 113         list_add_tail(&cmd->msg_l, &hdev->msg_tx_queue);
 114         mutex_unlock(&hdev->msg_tx_mutex);
 115
 116         schedule_work(&hdev->msg_tx_work);
 117
 118         return 0;
 119
 120 out_skb_err:
 121         skb_queue_purge(&cmd->msg_frags);
 122         kfree(cmd);
 123
 124         return err;
 125 }
 126
 127 /*
 128  * Receive hcp message for pipe, with type and cmd.
 129  * skb contains optional message data only.
 130  */
 131 void nfc_hci_hcp_message_rx(struct nfc_hci_dev *hdev, u8 pipe, u8 type,
 132                             u8 instruction, struct sk_buff *skb)
 133 {
 134         switch (type) {
 135         case NFC_HCI_HCP_RESPONSE:
 136                 nfc_hci_resp_received(hdev, instruction, skb);
 137                 break;
 138         case NFC_HCI_HCP_COMMAND:
 139                 nfc_hci_cmd_received(hdev, pipe, instruction, skb);
 140                 break;
 141         case NFC_HCI_HCP_EVENT:
 142                 nfc_hci_event_received(hdev, pipe, instruction, skb);
 143                 break;
 144         default:
 145                 pr_err("UNKNOWN MSG Type %d, instruction=%d\n",
 146                        type, instruction);
 147                 kfree_skb(skb);
 148                 break;
 149         }
 150 }