LXR linux/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 */
  33int 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
 120out_skb_err:
 121        skb_queue_purge(&cmd->msg_frags);
 122        kfree(cmd);
 123
 124        return err;
 125}
 126
 127u8 nfc_hci_pipe2gate(struct nfc_hci_dev *hdev, u8 pipe)
 128{
 129        int gate;
 130
 131        for (gate = 0; gate < NFC_HCI_MAX_GATES; gate++)
 132                if (hdev->gate2pipe[gate] == pipe)
 133                        return gate;
 134
 135        return 0xff;
 136}
 137
 138/*
 139 * Receive hcp message for pipe, with type and cmd.
 140 * skb contains optional message data only.
 141 */
 142void nfc_hci_hcp_message_rx(struct nfc_hci_dev *hdev, u8 pipe, u8 type,
 143                            u8 instruction, struct sk_buff *skb)
 144{
 145        switch (type) {
 146        case NFC_HCI_HCP_RESPONSE:
 147                nfc_hci_resp_received(hdev, instruction, skb);
 148                break;
 149        case NFC_HCI_HCP_COMMAND:
 150                nfc_hci_cmd_received(hdev, pipe, instruction, skb);
 151                break;
 152        case NFC_HCI_HCP_EVENT:
 153                nfc_hci_event_received(hdev, pipe, instruction, skb);
 154                break;
 155        default:
 156                pr_err("UNKNOWN MSG Type %d, instruction=%d\n",
 157                       type, instruction);
 158                kfree_skb(skb);
 159                break;
 160        }
 161}
 162