NFC: Changed HCI and PN544 HCI driver to use the new HCI LLC Core

The previous shdlc HCI driver and its header are removed from the tree.
PN544 now registers directly with HCI and passes the name of the llc it
requires (shdlc).
HCI instantiation now allocates the required llc instance. The llc is
started when the HCI device is brought up.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

4 files changed, 123 insertions, 1009 deletions

diff --git a/net/nfc/hci/Makefile b/net/nfc/hci/Makefile
index c4d65479629b..c5dbb6891b24 100644
--- a/net/nfc/hci/Makefile
+++ b/net/nfc/hci/Makefile
@@ -5,4 +5,4 @@
 obj-$(CONFIG_NFC_HCI) += hci.o
 
 hci-y			:= core.o hcp.o command.o llc.o llc_nop.o
-hci-$(CONFIG_NFC_SHDLC) += shdlc.o llc_shdlc.o
+hci-$(CONFIG_NFC_SHDLC) += llc_shdlc.o
diff --git a/net/nfc/hci/core.c b/net/nfc/hci/core.c
index 069e2d6056e5..c1129c22d835 100644
--- a/net/nfc/hci/core.c
+++ b/net/nfc/hci/core.c
@@ -78,7 +78,7 @@ next_msg:
 
 	pr_debug("msg_tx_queue has a cmd to send\n");
 	while ((skb = skb_dequeue(&msg->msg_frags)) != NULL) {
-		r = hdev->ops->xmit(hdev, skb);
+		r = nfc_llc_xmit_from_hci(hdev->llc, skb);
 		if (r < 0) {
 			kfree_skb(skb);
 			skb_queue_purge(&msg->msg_frags);
@@ -469,29 +469,38 @@ static int hci_dev_up(struct nfc_dev *nfc_dev)
 			return r;
 	}
 
+	r = nfc_llc_start(hdev->llc);
+	if (r < 0)
+		goto exit_close;
+
 	r = hci_dev_session_init(hdev);
 	if (r < 0)
-		goto exit;
+		goto exit_llc;
 
 	r = nfc_hci_send_event(hdev, NFC_HCI_RF_READER_A_GATE,
 			       NFC_HCI_EVT_END_OPERATION, NULL, 0);
 	if (r < 0)
-		goto exit;
+		goto exit_llc;
 
 	if (hdev->ops->hci_ready) {
 		r = hdev->ops->hci_ready(hdev);
 		if (r < 0)
-			goto exit;
+			goto exit_llc;
 	}
 
 	r = hci_dev_version(hdev);
 	if (r < 0)
-		goto exit;
+		goto exit_llc;
+
+	return 0;
+
+exit_llc:
+	nfc_llc_stop(hdev->llc);
+
+exit_close:
+	if (hdev->ops->close)
+		hdev->ops->close(hdev);
 
-exit:
-	if (r < 0)
-		if (hdev->ops->close)
-			hdev->ops->close(hdev);
 	return r;
 }
 
@@ -499,6 +508,8 @@ static int hci_dev_down(struct nfc_dev *nfc_dev)
 {
 	struct nfc_hci_dev *hdev = nfc_get_drvdata(nfc_dev);
 
+	nfc_llc_stop(hdev->llc);
+
 	if (hdev->ops->close)
 		hdev->ops->close(hdev);
 
@@ -620,6 +631,93 @@ static int hci_check_presence(struct nfc_dev *nfc_dev,
 	return 0;
 }
 
+static void nfc_hci_failure(struct nfc_hci_dev *hdev, int err)
+{
+	mutex_lock(&hdev->msg_tx_mutex);
+
+	if (hdev->cmd_pending_msg == NULL) {
+		nfc_driver_failure(hdev->ndev, err);
+		goto exit;
+	}
+
+	__nfc_hci_cmd_completion(hdev, err, NULL);
+
+exit:
+	mutex_unlock(&hdev->msg_tx_mutex);
+}
+
+static void nfc_hci_llc_failure(struct nfc_hci_dev *hdev, int err)
+{
+	nfc_hci_failure(hdev, err);
+}
+
+static void nfc_hci_recv_from_llc(struct nfc_hci_dev *hdev, struct sk_buff *skb)
+{
+	struct hcp_packet *packet;
+	u8 type;
+	u8 instruction;
+	struct sk_buff *hcp_skb;
+	u8 pipe;
+	struct sk_buff *frag_skb;
+	int msg_len;
+
+	packet = (struct hcp_packet *)skb->data;
+	if ((packet->header & ~NFC_HCI_FRAGMENT) == 0) {
+		skb_queue_tail(&hdev->rx_hcp_frags, skb);
+		return;
+	}
+
+	/* it's the last fragment. Does it need re-aggregation? */
+	if (skb_queue_len(&hdev->rx_hcp_frags)) {
+		pipe = packet->header & NFC_HCI_FRAGMENT;
+		skb_queue_tail(&hdev->rx_hcp_frags, skb);
+
+		msg_len = 0;
+		skb_queue_walk(&hdev->rx_hcp_frags, frag_skb) {
+			msg_len += (frag_skb->len -
+				    NFC_HCI_HCP_PACKET_HEADER_LEN);
+		}
+
+		hcp_skb = nfc_alloc_recv_skb(NFC_HCI_HCP_PACKET_HEADER_LEN +
+					     msg_len, GFP_KERNEL);
+		if (hcp_skb == NULL) {
+			nfc_hci_failure(hdev, -ENOMEM);
+			return;
+		}
+
+		*skb_put(hcp_skb, NFC_HCI_HCP_PACKET_HEADER_LEN) = pipe;
+
+		skb_queue_walk(&hdev->rx_hcp_frags, frag_skb) {
+			msg_len = frag_skb->len - NFC_HCI_HCP_PACKET_HEADER_LEN;
+			memcpy(skb_put(hcp_skb, msg_len),
+			       frag_skb->data + NFC_HCI_HCP_PACKET_HEADER_LEN,
+			       msg_len);
+		}
+
+		skb_queue_purge(&hdev->rx_hcp_frags);
+	} else {
+		packet->header &= NFC_HCI_FRAGMENT;
+		hcp_skb = skb;
+	}
+
+	/* if this is a response, dispatch immediately to
+	 * unblock waiting cmd context. Otherwise, enqueue to dispatch
+	 * in separate context where handler can also execute command.
+	 */
+	packet = (struct hcp_packet *)hcp_skb->data;
+	type = HCP_MSG_GET_TYPE(packet->message.header);
+	if (type == NFC_HCI_HCP_RESPONSE) {
+		pipe = packet->header;
+		instruction = HCP_MSG_GET_CMD(packet->message.header);
+		skb_pull(hcp_skb, NFC_HCI_HCP_PACKET_HEADER_LEN +
+			 NFC_HCI_HCP_MESSAGE_HEADER_LEN);
+		nfc_hci_hcp_message_rx(hdev, pipe, type, instruction, hcp_skb);
+	} else {
+		skb_queue_tail(&hdev->msg_rx_queue, hcp_skb);
+		queue_work(system_nrt_wq, &hdev->msg_rx_work);
+	}
+}
+
 static struct nfc_ops hci_nfc_ops = {
 	.dev_up = hci_dev_up,
 	.dev_down = hci_dev_down,
@@ -634,6 +732,7 @@ static struct nfc_ops hci_nfc_ops = {
 struct nfc_hci_dev *nfc_hci_allocate_device(struct nfc_hci_ops *ops,
 					    struct nfc_hci_init_data *init_data,
 					    u32 protocols,
+					    const char *llc_name,
 					    int tx_headroom,
 					    int tx_tailroom,
 					    int max_link_payload)
@@ -650,10 +749,19 @@ struct nfc_hci_dev *nfc_hci_allocate_device(struct nfc_hci_ops *ops,
 	if (hdev == NULL)
 		return NULL;
 
+	hdev->llc = nfc_llc_allocate(llc_name, hdev, ops->xmit,
+				     nfc_hci_recv_from_llc, tx_headroom,
+				     tx_tailroom, nfc_hci_llc_failure);
+	if (hdev->llc == NULL) {
+		kfree(hdev);
+		return NULL;
+	}
+
 	hdev->ndev = nfc_allocate_device(&hci_nfc_ops, protocols,
 					 tx_headroom + HCI_CMDS_HEADROOM,
 					 tx_tailroom);
 	if (!hdev->ndev) {
+		nfc_llc_free(hdev->llc);
 		kfree(hdev);
 		return NULL;
 	}
@@ -673,6 +781,7 @@ EXPORT_SYMBOL(nfc_hci_allocate_device);
 void nfc_hci_free_device(struct nfc_hci_dev *hdev)
 {
 	nfc_free_device(hdev->ndev);
+	nfc_llc_free(hdev->llc);
 	kfree(hdev);
 }
 EXPORT_SYMBOL(nfc_hci_free_device);
@@ -733,92 +842,15 @@ void *nfc_hci_get_clientdata(struct nfc_hci_dev *hdev)
 }
 EXPORT_SYMBOL(nfc_hci_get_clientdata);
 
-static void nfc_hci_failure(struct nfc_hci_dev *hdev, int err)
-{
-	mutex_lock(&hdev->msg_tx_mutex);
-
-	if (hdev->cmd_pending_msg == NULL) {
-		nfc_driver_failure(hdev->ndev, err);
-		goto exit;
-	}
-
-	__nfc_hci_cmd_completion(hdev, err, NULL);
-
-exit:
-	mutex_unlock(&hdev->msg_tx_mutex);
-}
-
 void nfc_hci_driver_failure(struct nfc_hci_dev *hdev, int err)
 {
 	nfc_hci_failure(hdev, err);
 }
 EXPORT_SYMBOL(nfc_hci_driver_failure);
 
-void nfc_hci_recv_frame(struct nfc_hci_dev *hdev, struct sk_buff *skb)
+void inline nfc_hci_recv_frame(struct nfc_hci_dev *hdev, struct sk_buff *skb)
 {
-	struct hcp_packet *packet;
-	u8 type;
-	u8 instruction;
-	struct sk_buff *hcp_skb;
-	u8 pipe;
-	struct sk_buff *frag_skb;
-	int msg_len;
-
-	packet = (struct hcp_packet *)skb->data;
-	if ((packet->header & ~NFC_HCI_FRAGMENT) == 0) {
-		skb_queue_tail(&hdev->rx_hcp_frags, skb);
-		return;
-	}
-
-	/* it's the last fragment. Does it need re-aggregation? */
-	if (skb_queue_len(&hdev->rx_hcp_frags)) {
-		pipe = packet->header & NFC_HCI_FRAGMENT;
-		skb_queue_tail(&hdev->rx_hcp_frags, skb);
-
-		msg_len = 0;
-		skb_queue_walk(&hdev->rx_hcp_frags, frag_skb) {
-			msg_len += (frag_skb->len -
-				    NFC_HCI_HCP_PACKET_HEADER_LEN);
-		}
-
-		hcp_skb = nfc_alloc_recv_skb(NFC_HCI_HCP_PACKET_HEADER_LEN +
-					     msg_len, GFP_KERNEL);
-		if (hcp_skb == NULL) {
-			nfc_hci_failure(hdev, -ENOMEM);
-			return;
-		}
-
-		*skb_put(hcp_skb, NFC_HCI_HCP_PACKET_HEADER_LEN) = pipe;
-
-		skb_queue_walk(&hdev->rx_hcp_frags, frag_skb) {
-			msg_len = frag_skb->len - NFC_HCI_HCP_PACKET_HEADER_LEN;
-			memcpy(skb_put(hcp_skb, msg_len),
-			       frag_skb->data + NFC_HCI_HCP_PACKET_HEADER_LEN,
-			       msg_len);
-		}
-
-		skb_queue_purge(&hdev->rx_hcp_frags);
-	} else {
-		packet->header &= NFC_HCI_FRAGMENT;
-		hcp_skb = skb;
-	}
-
-	/* if this is a response, dispatch immediately to
-	 * unblock waiting cmd context. Otherwise, enqueue to dispatch
-	 * in separate context where handler can also execute command.
-	 */
-	packet = (struct hcp_packet *)hcp_skb->data;
-	type = HCP_MSG_GET_TYPE(packet->message.header);
-	if (type == NFC_HCI_HCP_RESPONSE) {
-		pipe = packet->header;
-		instruction = HCP_MSG_GET_CMD(packet->message.header);
-		skb_pull(hcp_skb, NFC_HCI_HCP_PACKET_HEADER_LEN +
-			 NFC_HCI_HCP_MESSAGE_HEADER_LEN);
-		nfc_hci_hcp_message_rx(hdev, pipe, type, instruction, hcp_skb);
-	} else {
-		skb_queue_tail(&hdev->msg_rx_queue, hcp_skb);
-		queue_work(system_nrt_wq, &hdev->msg_rx_work);
-	}
+	nfc_llc_rcv_from_drv(hdev->llc, skb);
 }
 EXPORT_SYMBOL(nfc_hci_recv_frame);
 
@@ -832,7 +864,7 @@ static void __exit nfc_hci_exit(void)
 	nfc_llc_exit();
 }
 
-module_init(nfc_hci_init);
+subsys_initcall(nfc_hci_init);
 module_exit(nfc_hci_exit);
 
 MODULE_LICENSE("GPL");
diff --git a/net/nfc/hci/llc_shdlc.c b/net/nfc/hci/llc_shdlc.c
index bb191100ee96..fad6cd18d613 100644
--- a/net/nfc/hci/llc_shdlc.c
+++ b/net/nfc/hci/llc_shdlc.c
@@ -535,7 +535,7 @@ static void llc_shdlc_handle_send_queue(struct llc_shdlc *shdlc)
 
 		pr_debug("Sending I-Frame %d, waiting to rcv %d\n", shdlc->ns,
 			 shdlc->nr);
-	/*	SHDLC_DUMP_SKB("shdlc frame written", skb); */
+		SHDLC_DUMP_SKB("shdlc frame written", skb);
 
 		r = shdlc->xmit_to_drv(shdlc->hdev, skb);
 		if (r < 0) {
diff --git a/net/nfc/hci/shdlc.c b/net/nfc/hci/shdlc.c
deleted file mode 100644
index c63af7d3e859..000000000000
--- a/net/nfc/hci/shdlc.c
+++ /dev/null
@@ -1,918 +0,0 @@
-/*
- * 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) "shdlc: %s: " fmt, __func__
-
-#include <linux/sched.h>
-#include <linux/export.h>
-#include <linux/wait.h>
-#include <linux/slab.h>
-#include <linux/skbuff.h>
-
-#include <net/nfc/hci.h>
-#include <net/nfc/shdlc.h>
-
-#define SHDLC_LLC_HEAD_ROOM	2
-
-#define SHDLC_MAX_WINDOW	4
-#define SHDLC_SREJ_SUPPORT	false
-
-#define SHDLC_CONTROL_HEAD_MASK	0xe0
-#define SHDLC_CONTROL_HEAD_I	0x80
-#define SHDLC_CONTROL_HEAD_I2	0xa0
-#define SHDLC_CONTROL_HEAD_S	0xc0
-#define SHDLC_CONTROL_HEAD_U	0xe0
-
-#define SHDLC_CONTROL_NS_MASK	0x38
-#define SHDLC_CONTROL_NR_MASK	0x07
-#define SHDLC_CONTROL_TYPE_MASK	0x18
-
-#define SHDLC_CONTROL_M_MASK	0x1f
-
-enum sframe_type {
-	S_FRAME_RR = 0x00,
-	S_FRAME_REJ = 0x01,
-	S_FRAME_RNR = 0x02,
-	S_FRAME_SREJ = 0x03
-};
-
-enum uframe_modifier {
-	U_FRAME_UA = 0x06,
-	U_FRAME_RSET = 0x19
-};
-
-#define SHDLC_CONNECT_VALUE_MS	5
-#define SHDLC_T1_VALUE_MS(w)	((5 * w) / 4)
-#define SHDLC_T2_VALUE_MS	300
-
-#define SHDLC_DUMP_SKB(info, skb)				  \
-do {								  \
-	pr_debug("%s:\n", info);				  \
-	print_hex_dump(KERN_DEBUG, "shdlc: ", DUMP_PREFIX_OFFSET, \
-		       16, 1, skb->data, skb->len, 0);		  \
-} while (0)
-
-/* checks x < y <= z modulo 8 */
-static bool nfc_shdlc_x_lt_y_lteq_z(int x, int y, int z)
-{
-	if (x < z)
-		return ((x < y) && (y <= z)) ? true : false;
-	else
-		return ((y > x) || (y <= z)) ? true : false;
-}
-
-/* checks x <= y < z modulo 8 */
-static bool nfc_shdlc_x_lteq_y_lt_z(int x, int y, int z)
-{
-	if (x <= z)
-		return ((x <= y) && (y < z)) ? true : false;
-	else			/* x > z -> z+8 > x */
-		return ((y >= x) || (y < z)) ? true : false;
-}
-
-static struct sk_buff *nfc_shdlc_alloc_skb(struct nfc_shdlc *shdlc,
-					   int payload_len)
-{
-	struct sk_buff *skb;
-
-	skb = alloc_skb(shdlc->client_headroom + SHDLC_LLC_HEAD_ROOM +
-			shdlc->client_tailroom + payload_len, GFP_KERNEL);
-	if (skb)
-		skb_reserve(skb, shdlc->client_headroom + SHDLC_LLC_HEAD_ROOM);
-
-	return skb;
-}
-
-/* immediately sends an S frame. */
-static int nfc_shdlc_send_s_frame(struct nfc_shdlc *shdlc,
-				  enum sframe_type sframe_type, int nr)
-{
-	int r;
-	struct sk_buff *skb;
-
-	pr_debug("sframe_type=%d nr=%d\n", sframe_type, nr);
-
-	skb = nfc_shdlc_alloc_skb(shdlc, 0);
-	if (skb == NULL)
-		return -ENOMEM;
-
-	*skb_push(skb, 1) = SHDLC_CONTROL_HEAD_S | (sframe_type << 3) | nr;
-
-	r = shdlc->ops->xmit(shdlc, skb);
-
-	kfree_skb(skb);
-
-	return r;
-}
-
-/* immediately sends an U frame. skb may contain optional payload */
-static int nfc_shdlc_send_u_frame(struct nfc_shdlc *shdlc,
-				  struct sk_buff *skb,
-				  enum uframe_modifier uframe_modifier)
-{
-	int r;
-
-	pr_debug("uframe_modifier=%d\n", uframe_modifier);
-
-	*skb_push(skb, 1) = SHDLC_CONTROL_HEAD_U | uframe_modifier;
-
-	r = shdlc->ops->xmit(shdlc, skb);
-
-	kfree_skb(skb);
-
-	return r;
-}
-
-/*
- * Free ack_pending frames until y_nr - 1, and reset t2 according to
- * the remaining oldest ack_pending frame sent time
- */
-static void nfc_shdlc_reset_t2(struct nfc_shdlc *shdlc, int y_nr)
-{
-	struct sk_buff *skb;
-	int dnr = shdlc->dnr;	/* MUST initially be < y_nr */
-
-	pr_debug("release ack pending up to frame %d excluded\n", y_nr);
-
-	while (dnr != y_nr) {
-		pr_debug("release ack pending frame %d\n", dnr);
-
-		skb = skb_dequeue(&shdlc->ack_pending_q);
-		kfree_skb(skb);
-
-		dnr = (dnr + 1) % 8;
-	}
-
-	if (skb_queue_empty(&shdlc->ack_pending_q)) {
-		if (shdlc->t2_active) {
-			del_timer_sync(&shdlc->t2_timer);
-			shdlc->t2_active = false;
-
-			pr_debug
-			    ("All sent frames acked. Stopped T2(retransmit)\n");
-		}
-	} else {
-		skb = skb_peek(&shdlc->ack_pending_q);
-
-		mod_timer(&shdlc->t2_timer, *(unsigned long *)skb->cb +
-			  msecs_to_jiffies(SHDLC_T2_VALUE_MS));
-		shdlc->t2_active = true;
-
-		pr_debug
-		    ("Start T2(retransmit) for remaining unacked sent frames\n");
-	}
-}
-
-/*
- * Receive validated frames from lower layer. skb contains HCI payload only.
- * Handle according to algorithm at spec:10.8.2
- */
-static void nfc_shdlc_rcv_i_frame(struct nfc_shdlc *shdlc,
-				  struct sk_buff *skb, int ns, int nr)
-{
-	int x_ns = ns;
-	int y_nr = nr;
-
-	pr_debug("recvd I-frame %d, remote waiting frame %d\n", ns, nr);
-
-	if (shdlc->state != SHDLC_CONNECTED)
-		goto exit;
-
-	if (x_ns != shdlc->nr) {
-		nfc_shdlc_send_s_frame(shdlc, S_FRAME_REJ, shdlc->nr);
-		goto exit;
-	}
-
-	if (shdlc->t1_active == false) {
-		shdlc->t1_active = true;
-		mod_timer(&shdlc->t1_timer,
-			  msecs_to_jiffies(SHDLC_T1_VALUE_MS(shdlc->w)));
-		pr_debug("(re)Start T1(send ack)\n");
-	}
-
-	if (skb->len) {
-		nfc_hci_recv_frame(shdlc->hdev, skb);
-		skb = NULL;
-	}
-
-	shdlc->nr = (shdlc->nr + 1) % 8;
-
-	if (nfc_shdlc_x_lt_y_lteq_z(shdlc->dnr, y_nr, shdlc->ns)) {
-		nfc_shdlc_reset_t2(shdlc, y_nr);
-
-		shdlc->dnr = y_nr;
-	}
-
-exit:
-	kfree_skb(skb);
-}
-
-static void nfc_shdlc_rcv_ack(struct nfc_shdlc *shdlc, int y_nr)
-{
-	pr_debug("remote acked up to frame %d excluded\n", y_nr);
-
-	if (nfc_shdlc_x_lt_y_lteq_z(shdlc->dnr, y_nr, shdlc->ns)) {
-		nfc_shdlc_reset_t2(shdlc, y_nr);
-		shdlc->dnr = y_nr;
-	}
-}
-
-static void nfc_shdlc_requeue_ack_pending(struct nfc_shdlc *shdlc)
-{
-	struct sk_buff *skb;
-
-	pr_debug("ns reset to %d\n", shdlc->dnr);
-
-	while ((skb = skb_dequeue_tail(&shdlc->ack_pending_q))) {
-		skb_pull(skb, 1);  /* remove control field */
-		skb_queue_head(&shdlc->send_q, skb);
-	}
-	shdlc->ns = shdlc->dnr;
-}
-
-static void nfc_shdlc_rcv_rej(struct nfc_shdlc *shdlc, int y_nr)
-{
-	struct sk_buff *skb;
-
-	pr_debug("remote asks retransmition from frame %d\n", y_nr);
-
-	if (nfc_shdlc_x_lteq_y_lt_z(shdlc->dnr, y_nr, shdlc->ns)) {
-		if (shdlc->t2_active) {
-			del_timer_sync(&shdlc->t2_timer);
-			shdlc->t2_active = false;
-			pr_debug("Stopped T2(retransmit)\n");
-		}
-
-		if (shdlc->dnr != y_nr) {
-			while ((shdlc->dnr = ((shdlc->dnr + 1) % 8)) != y_nr) {
-				skb = skb_dequeue(&shdlc->ack_pending_q);
-				kfree_skb(skb);
-			}
-		}
-
-		nfc_shdlc_requeue_ack_pending(shdlc);
-	}
-}
-
-/* See spec RR:10.8.3 REJ:10.8.4 */
-static void nfc_shdlc_rcv_s_frame(struct nfc_shdlc *shdlc,
-				  enum sframe_type s_frame_type, int nr)
-{
-	struct sk_buff *skb;
-
-	if (shdlc->state != SHDLC_CONNECTED)
-		return;
-
-	switch (s_frame_type) {
-	case S_FRAME_RR:
-		nfc_shdlc_rcv_ack(shdlc, nr);
-		if (shdlc->rnr == true) {	/* see SHDLC 10.7.7 */
-			shdlc->rnr = false;
-			if (shdlc->send_q.qlen == 0) {
-				skb = nfc_shdlc_alloc_skb(shdlc, 0);
-				if (skb)
-					skb_queue_tail(&shdlc->send_q, skb);
-			}
-		}
-		break;
-	case S_FRAME_REJ:
-		nfc_shdlc_rcv_rej(shdlc, nr);
-		break;
-	case S_FRAME_RNR:
-		nfc_shdlc_rcv_ack(shdlc, nr);
-		shdlc->rnr = true;
-		break;
-	default:
-		break;
-	}
-}
-
-static void nfc_shdlc_connect_complete(struct nfc_shdlc *shdlc, int r)
-{
-	pr_debug("result=%d\n", r);
-
-	del_timer_sync(&shdlc->connect_timer);
-
-	if (r == 0) {
-		shdlc->ns = 0;
-		shdlc->nr = 0;
-		shdlc->dnr = 0;
-
-		shdlc->state = SHDLC_CONNECTED;
-	} else {
-		shdlc->state = SHDLC_DISCONNECTED;
-	}
-
-	shdlc->connect_result = r;
-
-	wake_up(shdlc->connect_wq);
-}
-
-static int nfc_shdlc_connect_initiate(struct nfc_shdlc *shdlc)
-{
-	struct sk_buff *skb;
-
-	pr_debug("\n");
-
-	skb = nfc_shdlc_alloc_skb(shdlc, 2);
-	if (skb == NULL)
-		return -ENOMEM;
-
-	*skb_put(skb, 1) = SHDLC_MAX_WINDOW;
-	*skb_put(skb, 1) = SHDLC_SREJ_SUPPORT ? 1 : 0;
-
-	return nfc_shdlc_send_u_frame(shdlc, skb, U_FRAME_RSET);
-}
-
-static int nfc_shdlc_connect_send_ua(struct nfc_shdlc *shdlc)
-{
-	struct sk_buff *skb;
-
-	pr_debug("\n");
-
-	skb = nfc_shdlc_alloc_skb(shdlc, 0);
-	if (skb == NULL)
-		return -ENOMEM;
-
-	return nfc_shdlc_send_u_frame(shdlc, skb, U_FRAME_UA);
-}
-
-static void nfc_shdlc_rcv_u_frame(struct nfc_shdlc *shdlc,
-				  struct sk_buff *skb,
-				  enum uframe_modifier u_frame_modifier)
-{
-	u8 w = SHDLC_MAX_WINDOW;
-	bool srej_support = SHDLC_SREJ_SUPPORT;
-	int r;
-
-	pr_debug("u_frame_modifier=%d\n", u_frame_modifier);
-
-	switch (u_frame_modifier) {
-	case U_FRAME_RSET:
-		if (shdlc->state == SHDLC_NEGOCIATING) {
-			/* we sent RSET, but chip wants to negociate */
-			if (skb->len > 0)
-				w = skb->data[0];
-
-			if (skb->len > 1)
-				srej_support = skb->data[1] & 0x01 ? true :
-					       false;
-
-			if ((w <= SHDLC_MAX_WINDOW) &&
-			    (SHDLC_SREJ_SUPPORT || (srej_support == false))) {
-				shdlc->w = w;
-				shdlc->srej_support = srej_support;
-				r = nfc_shdlc_connect_send_ua(shdlc);
-				nfc_shdlc_connect_complete(shdlc, r);
-			}
-		} else if (shdlc->state == SHDLC_CONNECTED) {
-			/*
-			 * Chip wants to reset link. This is unexpected and
-			 * unsupported.
-			 */
-			shdlc->hard_fault = -ECONNRESET;
-		}
-		break;
-	case U_FRAME_UA:
-		if ((shdlc->state == SHDLC_CONNECTING &&
-		     shdlc->connect_tries > 0) ||
-		    (shdlc->state == SHDLC_NEGOCIATING))
-			nfc_shdlc_connect_complete(shdlc, 0);
-		break;
-	default:
-		break;
-	}
-
-	kfree_skb(skb);
-}
-
-static void nfc_shdlc_handle_rcv_queue(struct nfc_shdlc *shdlc)
-{
-	struct sk_buff *skb;
-	u8 control;
-	int nr;
-	int ns;
-	enum sframe_type s_frame_type;
-	enum uframe_modifier u_frame_modifier;
-
-	if (shdlc->rcv_q.qlen)
-		pr_debug("rcvQlen=%d\n", shdlc->rcv_q.qlen);
-
-	while ((skb = skb_dequeue(&shdlc->rcv_q)) != NULL) {
-		control = skb->data[0];
-		skb_pull(skb, 1);
-		switch (control & SHDLC_CONTROL_HEAD_MASK) {
-		case SHDLC_CONTROL_HEAD_I:
-		case SHDLC_CONTROL_HEAD_I2:
-			ns = (control & SHDLC_CONTROL_NS_MASK) >> 3;
-			nr = control & SHDLC_CONTROL_NR_MASK;
-			nfc_shdlc_rcv_i_frame(shdlc, skb, ns, nr);
-			break;
-		case SHDLC_CONTROL_HEAD_S:
-			s_frame_type = (control & SHDLC_CONTROL_TYPE_MASK) >> 3;
-			nr = control & SHDLC_CONTROL_NR_MASK;
-			nfc_shdlc_rcv_s_frame(shdlc, s_frame_type, nr);
-			kfree_skb(skb);
-			break;
-		case SHDLC_CONTROL_HEAD_U:
-			u_frame_modifier = control & SHDLC_CONTROL_M_MASK;
-			nfc_shdlc_rcv_u_frame(shdlc, skb, u_frame_modifier);
-			break;
-		default:
-			pr_err("UNKNOWN Control=%d\n", control);
-			kfree_skb(skb);
-			break;
-		}
-	}
-}
-
-static int nfc_shdlc_w_used(int ns, int dnr)
-{
-	int unack_count;
-
-	if (dnr <= ns)
-		unack_count = ns - dnr;
-	else
-		unack_count = 8 - dnr + ns;
-
-	return unack_count;
-}
-
-/* Send frames according to algorithm at spec:10.8.1 */
-static void nfc_shdlc_handle_send_queue(struct nfc_shdlc *shdlc)
-{
-	struct sk_buff *skb;
-	int r;
-	unsigned long time_sent;
-
-	if (shdlc->send_q.qlen)
-		pr_debug
-		    ("sendQlen=%d ns=%d dnr=%d rnr=%s w_room=%d unackQlen=%d\n",
-		     shdlc->send_q.qlen, shdlc->ns, shdlc->dnr,
-		     shdlc->rnr == false ? "false" : "true",
-		     shdlc->w - nfc_shdlc_w_used(shdlc->ns, shdlc->dnr),
-		     shdlc->ack_pending_q.qlen);
-
-	while (shdlc->send_q.qlen && shdlc->ack_pending_q.qlen < shdlc->w &&
-	       (shdlc->rnr == false)) {
-
-		if (shdlc->t1_active) {
-			del_timer_sync(&shdlc->t1_timer);
-			shdlc->t1_active = false;
-			pr_debug("Stopped T1(send ack)\n");
-		}
-
-		skb = skb_dequeue(&shdlc->send_q);
-
-		*skb_push(skb, 1) = SHDLC_CONTROL_HEAD_I | (shdlc->ns << 3) |
-				    shdlc->nr;
-
-		pr_debug("Sending I-Frame %d, waiting to rcv %d\n", shdlc->ns,
-			 shdlc->nr);
-	/*	SHDLC_DUMP_SKB("shdlc frame written", skb); */
-
-		r = shdlc->ops->xmit(shdlc, skb);
-		if (r < 0) {
-			shdlc->hard_fault = r;
-			break;
-		}
-
-		shdlc->ns = (shdlc->ns + 1) % 8;
-
-		time_sent = jiffies;
-		*(unsigned long *)skb->cb = time_sent;
-
-		skb_queue_tail(&shdlc->ack_pending_q, skb);
-
-		if (shdlc->t2_active == false) {
-			shdlc->t2_active = true;
-			mod_timer(&shdlc->t2_timer, time_sent +
-				  msecs_to_jiffies(SHDLC_T2_VALUE_MS));
-			pr_debug("Started T2 (retransmit)\n");
-		}
-	}
-}
-
-static void nfc_shdlc_connect_timeout(unsigned long data)
-{
-	struct nfc_shdlc *shdlc = (struct nfc_shdlc *)data;
-
-	pr_debug("\n");
-
-	queue_work(system_nrt_wq, &shdlc->sm_work);
-}
-
-static void nfc_shdlc_t1_timeout(unsigned long data)
-{
-	struct nfc_shdlc *shdlc = (struct nfc_shdlc *)data;
-
-	pr_debug("SoftIRQ: need to send ack\n");
-
-	queue_work(system_nrt_wq, &shdlc->sm_work);
-}
-
-static void nfc_shdlc_t2_timeout(unsigned long data)
-{
-	struct nfc_shdlc *shdlc = (struct nfc_shdlc *)data;
-
-	pr_debug("SoftIRQ: need to retransmit\n");
-
-	queue_work(system_nrt_wq, &shdlc->sm_work);
-}
-
-static void nfc_shdlc_sm_work(struct work_struct *work)
-{
-	struct nfc_shdlc *shdlc = container_of(work, struct nfc_shdlc, sm_work);
-	int r;
-
-	pr_debug("\n");
-
-	mutex_lock(&shdlc->state_mutex);
-
-	switch (shdlc->state) {
-	case SHDLC_DISCONNECTED:
-		skb_queue_purge(&shdlc->rcv_q);
-		skb_queue_purge(&shdlc->send_q);
-		skb_queue_purge(&shdlc->ack_pending_q);
-		break;
-	case SHDLC_CONNECTING:
-		if (shdlc->hard_fault) {
-			nfc_shdlc_connect_complete(shdlc, shdlc->hard_fault);
-			break;
-		}
-
-		if (shdlc->connect_tries++ < 5)
-			r = nfc_shdlc_connect_initiate(shdlc);
-		else
-			r = -ETIME;
-		if (r < 0)
-			nfc_shdlc_connect_complete(shdlc, r);
-		else {
-			mod_timer(&shdlc->connect_timer, jiffies +
-				  msecs_to_jiffies(SHDLC_CONNECT_VALUE_MS));
-
-			shdlc->state = SHDLC_NEGOCIATING;
-		}
-		break;
-	case SHDLC_NEGOCIATING:
-		if (timer_pending(&shdlc->connect_timer) == 0) {
-			shdlc->state = SHDLC_CONNECTING;
-			queue_work(system_nrt_wq, &shdlc->sm_work);
-		}
-
-		nfc_shdlc_handle_rcv_queue(shdlc);
-
-		if (shdlc->hard_fault) {
-			nfc_shdlc_connect_complete(shdlc, shdlc->hard_fault);
-			break;
-		}
-		break;
-	case SHDLC_CONNECTED:
-		nfc_shdlc_handle_rcv_queue(shdlc);
-		nfc_shdlc_handle_send_queue(shdlc);
-
-		if (shdlc->t1_active && timer_pending(&shdlc->t1_timer) == 0) {
-			pr_debug
-			    ("Handle T1(send ack) elapsed (T1 now inactive)\n");
-
-			shdlc->t1_active = false;
-			r = nfc_shdlc_send_s_frame(shdlc, S_FRAME_RR,
-						   shdlc->nr);
-			if (r < 0)
-				shdlc->hard_fault = r;
-		}
-
-		if (shdlc->t2_active && timer_pending(&shdlc->t2_timer) == 0) {
-			pr_debug
-			    ("Handle T2(retransmit) elapsed (T2 inactive)\n");
-
-			shdlc->t2_active = false;
-
-			nfc_shdlc_requeue_ack_pending(shdlc);
-			nfc_shdlc_handle_send_queue(shdlc);
-		}
-
-		if (shdlc->hard_fault) {
-			nfc_hci_driver_failure(shdlc->hdev, shdlc->hard_fault);
-		}
-		break;
-	default:
-		break;
-	}
-	mutex_unlock(&shdlc->state_mutex);
-}
-
-/*
- * Called from syscall context to establish shdlc link. Sleeps until
- * link is ready or failure.
- */
-static int nfc_shdlc_connect(struct nfc_shdlc *shdlc)
-{
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(connect_wq);
-
-	pr_debug("\n");
-
-	mutex_lock(&shdlc->state_mutex);
-
-	shdlc->state = SHDLC_CONNECTING;
-	shdlc->connect_wq = &connect_wq;
-	shdlc->connect_tries = 0;
-	shdlc->connect_result = 1;
-
-	mutex_unlock(&shdlc->state_mutex);
-
-	queue_work(system_nrt_wq, &shdlc->sm_work);
-
-	wait_event(connect_wq, shdlc->connect_result != 1);
-
-	return shdlc->connect_result;
-}
-
-static void nfc_shdlc_disconnect(struct nfc_shdlc *shdlc)
-{
-	pr_debug("\n");
-
-	mutex_lock(&shdlc->state_mutex);
-
-	shdlc->state = SHDLC_DISCONNECTED;
-
-	mutex_unlock(&shdlc->state_mutex);
-
-	queue_work(system_nrt_wq, &shdlc->sm_work);
-}
-
-/*
- * Receive an incoming shdlc frame. Frame has already been crc-validated.
- * skb contains only LLC header and payload.
- * If skb == NULL, it is a notification that the link below is dead.
- */
-void nfc_shdlc_recv_frame(struct nfc_shdlc *shdlc, struct sk_buff *skb)
-{
-	if (skb == NULL) {
-		pr_err("NULL Frame -> link is dead\n");
-		shdlc->hard_fault = -EREMOTEIO;
-	} else {
-		SHDLC_DUMP_SKB("incoming frame", skb);
-		skb_queue_tail(&shdlc->rcv_q, skb);
-	}
-
-	queue_work(system_nrt_wq, &shdlc->sm_work);
-}
-EXPORT_SYMBOL(nfc_shdlc_recv_frame);
-
-static int nfc_shdlc_open(struct nfc_hci_dev *hdev)
-{
-	struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev);
-	int r;
-
-	pr_debug("\n");
-
-	if (shdlc->ops->open) {
-		r = shdlc->ops->open(shdlc);
-		if (r < 0)
-			return r;
-	}
-
-	r = nfc_shdlc_connect(shdlc);
-	if (r < 0 && shdlc->ops->close)
-		shdlc->ops->close(shdlc);
-
-	return r;
-}
-
-static void nfc_shdlc_close(struct nfc_hci_dev *hdev)
-{
-	struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev);
-
-	pr_debug("\n");
-
-	nfc_shdlc_disconnect(shdlc);
-
-	if (shdlc->ops->close)
-		shdlc->ops->close(shdlc);
-}
-
-static int nfc_shdlc_hci_ready(struct nfc_hci_dev *hdev)
-{
-	struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev);
-	int r = 0;
-
-	pr_debug("\n");
-
-	if (shdlc->ops->hci_ready)
-		r = shdlc->ops->hci_ready(shdlc);
-
-	return r;
-}
-
-static int nfc_shdlc_xmit(struct nfc_hci_dev *hdev, struct sk_buff *skb)
-{
-	struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev);
-
-	SHDLC_DUMP_SKB("queuing HCP packet to shdlc", skb);
-
-	skb_queue_tail(&shdlc->send_q, skb);
-
-	queue_work(system_nrt_wq, &shdlc->sm_work);
-
-	return 0;
-}
-
-static int nfc_shdlc_start_poll(struct nfc_hci_dev *hdev,
-				u32 im_protocols, u32 tm_protocols)
-{
-	struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev);
-
-	pr_debug("\n");
-
-	if (shdlc->ops->start_poll)
-		return shdlc->ops->start_poll(shdlc,
-					      im_protocols, tm_protocols);
-
-	return 0;
-}
-
-static int nfc_shdlc_target_from_gate(struct nfc_hci_dev *hdev, u8 gate,
-				      struct nfc_target *target)
-{
-	struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev);
-
-	if (shdlc->ops->target_from_gate)
-		return shdlc->ops->target_from_gate(shdlc, gate, target);
-
-	return -EPERM;
-}
-
-static int nfc_shdlc_complete_target_discovered(struct nfc_hci_dev *hdev,
-						u8 gate,
-						struct nfc_target *target)
-{
-	struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev);
-
-	pr_debug("\n");
-
-	if (shdlc->ops->complete_target_discovered)
-		return shdlc->ops->complete_target_discovered(shdlc, gate,
-							      target);
-
-	return 0;
-}
-
-static int nfc_shdlc_data_exchange(struct nfc_hci_dev *hdev,
-				   struct nfc_target *target,
-				   struct sk_buff *skb,
-				   data_exchange_cb_t cb, void *cb_context)
-{
-	struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev);
-
-	if (shdlc->ops->data_exchange)
-		return shdlc->ops->data_exchange(shdlc, target, skb, cb,
-						 cb_context);
-
-	return -EPERM;
-}
-
-static int nfc_shdlc_check_presence(struct nfc_hci_dev *hdev,
-				    struct nfc_target *target)
-{
-	struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev);
-
-	if (shdlc->ops->check_presence)
-		return shdlc->ops->check_presence(shdlc, target);
-
-	return 0;
-}
-
-static struct nfc_hci_ops shdlc_ops = {
-	.open = nfc_shdlc_open,
-	.close = nfc_shdlc_close,
-	.hci_ready = nfc_shdlc_hci_ready,
-	.xmit = nfc_shdlc_xmit,
-	.start_poll = nfc_shdlc_start_poll,
-	.target_from_gate = nfc_shdlc_target_from_gate,
-	.complete_target_discovered = nfc_shdlc_complete_target_discovered,
-	.data_exchange = nfc_shdlc_data_exchange,
-	.check_presence = nfc_shdlc_check_presence,
-};
-
-struct nfc_shdlc *nfc_shdlc_allocate(struct nfc_shdlc_ops *ops,
-				     struct nfc_hci_init_data *init_data,
-				     u32 protocols,
-				     int tx_headroom, int tx_tailroom,
-				     int max_link_payload, const char *devname)
-{
-	struct nfc_shdlc *shdlc;
-	int r;
-
-	if (ops->xmit == NULL)
-		return NULL;
-
-	shdlc = kzalloc(sizeof(struct nfc_shdlc), GFP_KERNEL);
-	if (shdlc == NULL)
-		return NULL;
-
-	mutex_init(&shdlc->state_mutex);
-	shdlc->ops = ops;
-	shdlc->state = SHDLC_DISCONNECTED;
-
-	init_timer(&shdlc->connect_timer);
-	shdlc->connect_timer.data = (unsigned long)shdlc;
-	shdlc->connect_timer.function = nfc_shdlc_connect_timeout;
-
-	init_timer(&shdlc->t1_timer);
-	shdlc->t1_timer.data = (unsigned long)shdlc;
-	shdlc->t1_timer.function = nfc_shdlc_t1_timeout;
-
-	init_timer(&shdlc->t2_timer);
-	shdlc->t2_timer.data = (unsigned long)shdlc;
-	shdlc->t2_timer.function = nfc_shdlc_t2_timeout;
-
-	shdlc->w = SHDLC_MAX_WINDOW;
-	shdlc->srej_support = SHDLC_SREJ_SUPPORT;
-
-	skb_queue_head_init(&shdlc->rcv_q);
-	skb_queue_head_init(&shdlc->send_q);
-	skb_queue_head_init(&shdlc->ack_pending_q);
-
-	INIT_WORK(&shdlc->sm_work, nfc_shdlc_sm_work);
-
-	shdlc->client_headroom = tx_headroom;
-	shdlc->client_tailroom = tx_tailroom;
-
-	shdlc->hdev = nfc_hci_allocate_device(&shdlc_ops, init_data, protocols,
-					      tx_headroom + SHDLC_LLC_HEAD_ROOM,
-					      tx_tailroom,
-					      max_link_payload);
-	if (shdlc->hdev == NULL)
-		goto err_allocdev;
-
-	nfc_hci_set_clientdata(shdlc->hdev, shdlc);
-
-	r = nfc_hci_register_device(shdlc->hdev);
-	if (r < 0)
-		goto err_regdev;
-
-	return shdlc;
-
-err_regdev:
-	nfc_hci_free_device(shdlc->hdev);
-
-err_allocdev:
-	kfree(shdlc);
-
-	return NULL;
-}
-EXPORT_SYMBOL(nfc_shdlc_allocate);
-
-void nfc_shdlc_free(struct nfc_shdlc *shdlc)
-{
-	pr_debug("\n");
-
-	nfc_hci_unregister_device(shdlc->hdev);
-	nfc_hci_free_device(shdlc->hdev);
-
-	cancel_work_sync(&shdlc->sm_work);
-
-	skb_queue_purge(&shdlc->rcv_q);
-	skb_queue_purge(&shdlc->send_q);
-	skb_queue_purge(&shdlc->ack_pending_q);
-
-	kfree(shdlc);
-}
-EXPORT_SYMBOL(nfc_shdlc_free);
-
-void nfc_shdlc_set_clientdata(struct nfc_shdlc *shdlc, void *clientdata)
-{
-	pr_debug("\n");
-
-	shdlc->clientdata = clientdata;
-}
-EXPORT_SYMBOL(nfc_shdlc_set_clientdata);
-
-void *nfc_shdlc_get_clientdata(struct nfc_shdlc *shdlc)
-{
-	return shdlc->clientdata;
-}
-EXPORT_SYMBOL(nfc_shdlc_get_clientdata);
-
-struct nfc_hci_dev *nfc_shdlc_get_hci_dev(struct nfc_shdlc *shdlc)
-{
-	return shdlc->hdev;
-}
-EXPORT_SYMBOL(nfc_shdlc_get_hci_dev);