NFC: basic NCI protocol implementation

The NFC Controller Interface (NCI) is a standard
communication protocol between an NFC Controller (NFCC)
and a Device Host (DH), defined by the NFC Forum.

Signed-off-by: Ilan Elias <ilane@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 258 insertions, 0 deletions

diff --git a/net/nfc/nci/ntf.c b/net/nfc/nci/ntf.c
new file mode 100644
index 0000000..8dd7535
--- /dev/null
+++ b/net/nfc/nci/ntf.c
@@ -0,0 +1,258 @@
+/*
+ *  The NFC Controller Interface is the communication protocol between an
+ *  NFC Controller (NFCC) and a Device Host (DH).
+ *
+ *  Copyright (C) 2011 Texas Instruments, Inc.
+ *
+ *  Written by Ilan Elias <ilane@ti.com>
+ *
+ *  Acknowledgements:
+ *  This file is based on hci_event.c, which was written
+ *  by Maxim Krasnyansky.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation
+ *
+ *  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
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/bitops.h>
+#include <linux/skbuff.h>
+
+#include "../nfc.h"
+#include <net/nfc/nci.h>
+#include <net/nfc/nci_core.h>
+#include <linux/nfc.h>
+
+/* Handle NCI Notification packets */
+
+static void nci_core_conn_credits_ntf_packet(struct nci_dev *ndev,
+						struct sk_buff *skb)
+{
+	struct nci_core_conn_credit_ntf *ntf = (void *) skb->data;
+	int i;
+
+	nfc_dbg("entry, num_entries %d", ntf->num_entries);
+
+	if (ntf->num_entries > NCI_MAX_NUM_CONN)
+		ntf->num_entries = NCI_MAX_NUM_CONN;
+
+	/* update the credits */
+	for (i = 0; i < ntf->num_entries; i++) {
+		nfc_dbg("entry[%d]: conn_id %d, credits %d", i,
+			ntf->conn_entries[i].conn_id,
+			ntf->conn_entries[i].credits);
+
+		if (ntf->conn_entries[i].conn_id == ndev->conn_id) {
+			/* found static rf connection */
+			atomic_add(ntf->conn_entries[i].credits,
+				&ndev->credits_cnt);
+		}
+	}
+
+	/* trigger the next tx */
+	if (!skb_queue_empty(&ndev->tx_q))
+		queue_work(ndev->tx_wq, &ndev->tx_work);
+}
+
+static void nci_rf_field_info_ntf_packet(struct nci_dev *ndev,
+					struct sk_buff *skb)
+{
+	struct nci_rf_field_info_ntf *ntf = (void *) skb->data;
+
+	nfc_dbg("entry, rf_field_status %d", ntf->rf_field_status);
+}
+
+static int nci_rf_activate_nfca_passive_poll(struct nci_dev *ndev,
+			struct nci_rf_activate_ntf *ntf, __u8 *data)
+{
+	struct rf_tech_specific_params_nfca_poll *nfca_poll;
+	struct activation_params_nfca_poll_iso_dep *nfca_poll_iso_dep;
+
+	nfca_poll = &ntf->rf_tech_specific_params.nfca_poll;
+	nfca_poll_iso_dep = &ntf->activation_params.nfca_poll_iso_dep;
+
+	nfca_poll->sens_res = __le16_to_cpu(*((__u16 *)data));
+	data += 2;
+
+	nfca_poll->nfcid1_len = *data++;
+
+	nfc_dbg("sens_res 0x%x, nfcid1_len %d",
+		nfca_poll->sens_res,
+		nfca_poll->nfcid1_len);
+
+	memcpy(nfca_poll->nfcid1, data, nfca_poll->nfcid1_len);
+	data += nfca_poll->nfcid1_len;
+
+	nfca_poll->sel_res_len = *data++;
+
+	if (nfca_poll->sel_res_len != 0)
+		nfca_poll->sel_res = *data++;
+
+	ntf->rf_interface_type = *data++;
+	ntf->activation_params_len = *data++;
+
+	nfc_dbg("sel_res_len %d, sel_res 0x%x, rf_interface_type %d, activation_params_len %d",
+		nfca_poll->sel_res_len,
+		nfca_poll->sel_res,
+		ntf->rf_interface_type,
+		ntf->activation_params_len);
+
+	switch (ntf->rf_interface_type) {
+	case NCI_RF_INTERFACE_ISO_DEP:
+		nfca_poll_iso_dep->rats_res_len = *data++;
+		if (nfca_poll_iso_dep->rats_res_len > 0) {
+			memcpy(nfca_poll_iso_dep->rats_res,
+				data,
+				nfca_poll_iso_dep->rats_res_len);
+		}
+		break;
+
+	case NCI_RF_INTERFACE_FRAME:
+		/* no activation params */
+		break;
+
+	default:
+		nfc_err("unsupported rf_interface_type 0x%x",
+			ntf->rf_interface_type);
+		return -EPROTO;
+	}
+
+	return 0;
+}
+
+static void nci_target_found(struct nci_dev *ndev,
+				struct nci_rf_activate_ntf *ntf)
+{
+	struct nfc_target nfc_tgt;
+
+	if (ntf->rf_protocol == NCI_RF_PROTOCOL_T2T)	/* T2T MifareUL */
+		nfc_tgt.supported_protocols = NFC_PROTO_MIFARE_MASK;
+	else if (ntf->rf_protocol == NCI_RF_PROTOCOL_ISO_DEP)	/* 4A */
+		nfc_tgt.supported_protocols = NFC_PROTO_ISO14443_MASK;
+
+	nfc_tgt.sens_res = ntf->rf_tech_specific_params.nfca_poll.sens_res;
+	nfc_tgt.sel_res = ntf->rf_tech_specific_params.nfca_poll.sel_res;
+
+	if (!(nfc_tgt.supported_protocols & ndev->poll_prots)) {
+		nfc_dbg("the target found does not have the desired protocol");
+		return;
+	}
+
+	nfc_dbg("new target found,  supported_protocols 0x%x",
+		nfc_tgt.supported_protocols);
+
+	ndev->target_available_prots = nfc_tgt.supported_protocols;
+
+	nfc_targets_found(ndev->nfc_dev, &nfc_tgt, 1);
+}
+
+static void nci_rf_activate_ntf_packet(struct nci_dev *ndev,
+					struct sk_buff *skb)
+{
+	struct nci_rf_activate_ntf ntf;
+	__u8 *data = skb->data;
+	int rc = -1;
+
+	clear_bit(NCI_DISCOVERY, &ndev->flags);
+	set_bit(NCI_POLL_ACTIVE, &ndev->flags);
+
+	ntf.target_handle = *data++;
+	ntf.rf_protocol = *data++;
+	ntf.rf_tech_and_mode = *data++;
+	ntf.rf_tech_specific_params_len = *data++;
+
+	nfc_dbg("target_handle %d, rf_protocol 0x%x, rf_tech_and_mode 0x%x, rf_tech_specific_params_len %d",
+		ntf.target_handle,
+		ntf.rf_protocol,
+		ntf.rf_tech_and_mode,
+		ntf.rf_tech_specific_params_len);
+
+	switch (ntf.rf_tech_and_mode) {
+	case NCI_NFC_A_PASSIVE_POLL_MODE:
+		rc = nci_rf_activate_nfca_passive_poll(ndev, &ntf,
+			data);
+		break;
+
+	default:
+		nfc_err("unsupported rf_tech_and_mode 0x%x",
+			ntf.rf_tech_and_mode);
+		return;
+	}
+
+	if (!rc)
+		nci_target_found(ndev, &ntf);
+}
+
+static void nci_rf_deactivate_ntf_packet(struct nci_dev *ndev,
+					struct sk_buff *skb)
+{
+	__u8 type = skb->data[0];
+
+	nfc_dbg("entry, type 0x%x", type);
+
+	clear_bit(NCI_POLL_ACTIVE, &ndev->flags);
+	ndev->target_active_prot = 0;
+
+	/* drop tx data queue */
+	skb_queue_purge(&ndev->tx_q);
+
+	/* drop partial rx data packet */
+	if (ndev->rx_data_reassembly) {
+		kfree_skb(ndev->rx_data_reassembly);
+		ndev->rx_data_reassembly = 0;
+	}
+
+	/* complete the data exchange transaction, if exists */
+	if (ndev->data_exchange_cb)
+		nci_data_exchange_complete(ndev, NULL, -EIO);
+}
+
+void nci_ntf_packet(struct nci_dev *ndev, struct sk_buff *skb)
+{
+	__u16 ntf_opcode = nci_opcode(skb->data);
+
+	nfc_dbg("NCI RX: MT=ntf, PBF=%d, GID=0x%x, OID=0x%x, plen=%d",
+			nci_pbf(skb->data),
+			nci_opcode_gid(ntf_opcode),
+			nci_opcode_oid(ntf_opcode),
+			nci_plen(skb->data));
+
+	/* strip the nci control header */
+	skb_pull(skb, NCI_CTRL_HDR_SIZE);
+
+	switch (ntf_opcode) {
+	case NCI_OP_CORE_CONN_CREDITS_NTF:
+		nci_core_conn_credits_ntf_packet(ndev, skb);
+		break;
+
+	case NCI_OP_RF_FIELD_INFO_NTF:
+		nci_rf_field_info_ntf_packet(ndev, skb);
+		break;
+
+	case NCI_OP_RF_ACTIVATE_NTF:
+		nci_rf_activate_ntf_packet(ndev, skb);
+		break;
+
+	case NCI_OP_RF_DEACTIVATE_NTF:
+		nci_rf_deactivate_ntf_packet(ndev, skb);
+		break;
+
+	default:
+		nfc_err("unknown ntf opcode 0x%x", ntf_opcode);
+		break;
+	}
+
+	kfree_skb(skb);
+}