net/nfc/hci/hcp.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2012  Intel Corporation. All rights reserved.
   4  */
   5
   6 #define pr_fmt(fmt) "hci: %s: " fmt, __func__
   7
   8 #include <linux/init.h>
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11
  12 #include <net/nfc/hci.h>
  13
  14 #include "hci.h"
  15
  16 /*
  17  * Payload is the HCP message data only. Instruction will be prepended.
  18  * Guarantees that cb will be called upon completion or timeout delay
  19  * counted from the moment the cmd is sent to the transport.
  20  */
  21 int nfc_hci_hcp_message_tx(struct nfc_hci_dev *hdev, u8 pipe,
  22                            u8 type, u8 instruction,
  23                            const u8 *payload, size_t payload_len,
  24                            data_exchange_cb_t cb, void *cb_context,
  25                            unsigned long completion_delay)
  26 {
  27         struct nfc_dev *ndev = hdev->ndev;
  28         struct hci_msg *cmd;
  29         const u8 *ptr = payload;
  30         int hci_len, err;
  31         bool firstfrag = true;
  32
  33         cmd = kzalloc(sizeof(struct hci_msg), GFP_KERNEL);
  34         if (cmd == NULL)
  35                 return -ENOMEM;
  36
  37         INIT_LIST_HEAD(&cmd->msg_l);
  38         skb_queue_head_init(&cmd->msg_frags);
  39         cmd->wait_response = (type == NFC_HCI_HCP_COMMAND) ? true : false;
  40         cmd->cb = cb;
  41         cmd->cb_context = cb_context;
  42         cmd->completion_delay = completion_delay;
  43
  44         hci_len = payload_len + 1;
  45         while (hci_len > 0) {
  46                 struct sk_buff *skb;
  47                 int skb_len, data_link_len;
  48                 struct hcp_packet *packet;
  49
  50                 if (NFC_HCI_HCP_PACKET_HEADER_LEN + hci_len <=
  51                     hdev->max_data_link_payload)
  52                         data_link_len = hci_len;
  53                 else
  54                         data_link_len = hdev->max_data_link_payload -
  55                                         NFC_HCI_HCP_PACKET_HEADER_LEN;
  56
  57                 skb_len = ndev->tx_headroom + NFC_HCI_HCP_PACKET_HEADER_LEN +
  58                           data_link_len + ndev->tx_tailroom;
  59                 hci_len -= data_link_len;
  60
  61                 skb = alloc_skb(skb_len, GFP_KERNEL);
  62                 if (skb == NULL) {
  63                         err = -ENOMEM;
  64                         goto out_skb_err;
  65                 }
  66                 skb_reserve(skb, ndev->tx_headroom);
  67
  68                 skb_put(skb, NFC_HCI_HCP_PACKET_HEADER_LEN + data_link_len);
  69
  70                 /* Only the last fragment will have the cb bit set to 1 */
  71                 packet = (struct hcp_packet *)skb->data;
  72                 packet->header = pipe;
  73                 if (firstfrag) {
  74                         firstfrag = false;
  75                         packet->message.header = HCP_HEADER(type, instruction);
  76                 } else {
  77                         packet->message.header = *ptr++;
  78                 }
  79                 if (ptr) {
  80                         memcpy(packet->message.data, ptr, data_link_len - 1);
  81                         ptr += data_link_len - 1;
  82                 }
  83
  84                 /* This is the last fragment, set the cb bit */
  85                 if (hci_len == 0)
  86                         packet->header |= ~NFC_HCI_FRAGMENT;
  87
  88                 skb_queue_tail(&cmd->msg_frags, skb);
  89         }
  90
  91         mutex_lock(&hdev->msg_tx_mutex);
  92
  93         if (hdev->shutting_down) {
  94                 err = -ESHUTDOWN;
  95                 mutex_unlock(&hdev->msg_tx_mutex);
  96                 goto out_skb_err;
  97         }
  98
  99         list_add_tail(&cmd->msg_l, &hdev->msg_tx_queue);
 100         mutex_unlock(&hdev->msg_tx_mutex);
 101
 102         schedule_work(&hdev->msg_tx_work);
 103
 104         return 0;
 105
 106 out_skb_err:
 107         skb_queue_purge(&cmd->msg_frags);
 108         kfree(cmd);
 109
 110         return err;
 111 }
 112
 113 /*
 114  * Receive hcp message for pipe, with type and cmd.
 115  * skb contains optional message data only.
 116  */
 117 void nfc_hci_hcp_message_rx(struct nfc_hci_dev *hdev, u8 pipe, u8 type,
 118                             u8 instruction, struct sk_buff *skb)
 119 {
 120         switch (type) {
 121         case NFC_HCI_HCP_RESPONSE:
 122                 nfc_hci_resp_received(hdev, instruction, skb);
 123                 break;
 124         case NFC_HCI_HCP_COMMAND:
 125                 nfc_hci_cmd_received(hdev, pipe, instruction, skb);
 126                 break;
 127         case NFC_HCI_HCP_EVENT:
 128                 nfc_hci_event_received(hdev, pipe, instruction, skb);
 129                 break;
 130         default:
 131                 pr_err("UNKNOWN MSG Type %d, instruction=%d\n",
 132                        type, instruction);
 133                 kfree_skb(skb);
 134                 break;
 135         }
 136 }