NFC: HCI support

This is an implementation of ETSI TS 102 622 specification.
Many NFC chipsets use HCI as the host <-> target protocol on top of a
serial link like i2c.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 156 insertions, 0 deletions

diff --git a/net/nfc/hci/hcp.c b/net/nfc/hci/hcp.c
new file mode 100644
index 000000000000..7212cf2c5785
--- /dev/null
+++ b/net/nfc/hci/hcp.c
@@ -0,0 +1,156 @@
+/*
+ * 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,
+			   hci_cmd_cb_t cb, void *cb_data,
+			   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_data;
+	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(&hdev->msg_tx_queue, &cmd->msg_l);
+	mutex_unlock(&hdev->msg_tx_mutex);
+
+	queue_work(hdev->msg_tx_wq, &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;
+	}
+}