static int st21nfca_hci_load_session()

in st21nfca/core.c [104:203]

• 58 lines of code
• 12 McCabe index (conditional complexity)

static int st21nfca_hci_load_session(struct nfc_hci_dev *hdev)
{
	int i, j, r;
	struct sk_buff *skb_pipe_list, *skb_pipe_info;
	struct st21nfca_pipe_info *info;

	u8 pipe_list[] = { ST21NFCA_DM_GETINFO_PIPE_LIST,
		NFC_HCI_TERMINAL_HOST_ID
	};
	u8 pipe_info[] = { ST21NFCA_DM_GETINFO_PIPE_INFO,
		NFC_HCI_TERMINAL_HOST_ID, 0
	};

	/* On ST21NFCA device pipes number are dynamics
	 * A maximum of 16 pipes can be created at the same time
	 * If pipes are already created, hci_dev_up will fail.
	 * Doing a clear all pipe is a bad idea because:
	 * - It does useless EEPROM cycling
	 * - It might cause issue for secure elements support
	 * (such as removing connectivity or APDU reader pipe)
	 * A better approach on ST21NFCA is to:
	 * - get a pipe list for each host.
	 * (eg: NFC_HCI_HOST_CONTROLLER_ID for now).
	 * (TODO Later on UICC HOST and eSE HOST)
	 * - get pipe information
	 * - match retrieved pipe list in st21nfca_gates
	 * ST21NFCA_DEVICE_MGNT_GATE is a proprietary gate
	 * with ST21NFCA_DEVICE_MGNT_PIPE.
	 * Pipe can be closed and need to be open.
	 */
	r = nfc_hci_connect_gate(hdev, NFC_HCI_HOST_CONTROLLER_ID,
				ST21NFCA_DEVICE_MGNT_GATE,
				ST21NFCA_DEVICE_MGNT_PIPE);
	if (r < 0)
		return r;

	/* Get pipe list */
	r = nfc_hci_send_cmd(hdev, ST21NFCA_DEVICE_MGNT_GATE,
			ST21NFCA_DM_GETINFO, pipe_list, sizeof(pipe_list),
			&skb_pipe_list);
	if (r < 0)
		return r;

	/* Complete the existing gate_pipe table */
	for (i = 0; i < skb_pipe_list->len; i++) {
		pipe_info[2] = skb_pipe_list->data[i];
		r = nfc_hci_send_cmd(hdev, ST21NFCA_DEVICE_MGNT_GATE,
					ST21NFCA_DM_GETINFO, pipe_info,
					sizeof(pipe_info), &skb_pipe_info);
		if (r)
			continue;

		/*
		 * Match pipe ID and gate ID
		 * Output format from ST21NFC_DM_GETINFO is:
		 * - pipe state (1byte)
		 * - source hid (1byte)
		 * - source gid (1byte)
		 * - destination hid (1byte)
		 * - destination gid (1byte)
		 */
		info = (struct st21nfca_pipe_info *) skb_pipe_info->data;
		if (info->dst_gate_id == ST21NFCA_APDU_READER_GATE &&
			info->src_host_id == NFC_HCI_UICC_HOST_ID) {
			pr_err("Unexpected apdu_reader pipe on host %x\n",
				info->src_host_id);
			kfree_skb(skb_pipe_info);
			continue;
		}

		for (j = 3; (j < ARRAY_SIZE(st21nfca_gates)) &&
			(st21nfca_gates[j].gate != info->dst_gate_id) ; j++)
			;

		if (j < ARRAY_SIZE(st21nfca_gates) &&
			st21nfca_gates[j].gate == info->dst_gate_id &&
			ST21NFCA_DM_IS_PIPE_OPEN(info->pipe_state)) {
			hdev->init_data.gates[j].pipe = pipe_info[2];

			hdev->gate2pipe[st21nfca_gates[j].gate] =
						pipe_info[2];
			hdev->pipes[pipe_info[2]].gate =
						st21nfca_gates[j].gate;
			hdev->pipes[pipe_info[2]].dest_host =
						info->src_host_id;
		}
		kfree_skb(skb_pipe_info);
	}

	/*
	 * 3 gates have a well known pipe ID. Only NFC_HCI_LINK_MGMT_GATE
	 * is not yet open at this stage.
	 */
	r = nfc_hci_connect_gate(hdev, NFC_HCI_HOST_CONTROLLER_ID,
				 NFC_HCI_LINK_MGMT_GATE,
				 NFC_HCI_LINK_MGMT_PIPE);

	kfree_skb(skb_pipe_list);
	return r;
}