hcp.c

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/*
 * 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, write to the
 * Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#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);
    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\n",
               type, instruction);
        kfree_skb(skb);
        break;
    }
}