Initial import

1 files changed, 300 insertions, 0 deletions

diff --git a/drivers/nfc/st21nfcb/ndlc.c b/drivers/nfc/st21nfcb/ndlc.c
new file mode 100644
index 000000000..6014b5859
--- /dev/null
+++ b/drivers/nfc/st21nfcb/ndlc.c
@@ -0,0 +1,300 @@
+/*
+ * Low Level Transport (NDLC) Driver for STMicroelectronics NFC Chip
+ *
+ * Copyright (C) 2014  STMicroelectronics SAS. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/sched.h>
+#include <net/nfc/nci_core.h>
+
+#include "ndlc.h"
+#include "st21nfcb.h"
+
+#define NDLC_TIMER_T1		100
+#define NDLC_TIMER_T1_WAIT	400
+#define NDLC_TIMER_T2		1200
+
+#define PCB_TYPE_DATAFRAME		0x80
+#define PCB_TYPE_SUPERVISOR		0xc0
+#define PCB_TYPE_MASK			PCB_TYPE_SUPERVISOR
+
+#define PCB_SYNC_ACK			0x20
+#define PCB_SYNC_NACK			0x10
+#define PCB_SYNC_WAIT			0x30
+#define PCB_SYNC_NOINFO			0x00
+#define PCB_SYNC_MASK			PCB_SYNC_WAIT
+
+#define PCB_DATAFRAME_RETRANSMIT_YES	0x00
+#define PCB_DATAFRAME_RETRANSMIT_NO	0x04
+#define PCB_DATAFRAME_RETRANSMIT_MASK	PCB_DATAFRAME_RETRANSMIT_NO
+
+#define PCB_SUPERVISOR_RETRANSMIT_YES	0x00
+#define PCB_SUPERVISOR_RETRANSMIT_NO	0x02
+#define PCB_SUPERVISOR_RETRANSMIT_MASK	PCB_SUPERVISOR_RETRANSMIT_NO
+
+#define PCB_FRAME_CRC_INFO_PRESENT	0x08
+#define PCB_FRAME_CRC_INFO_NOTPRESENT	0x00
+#define PCB_FRAME_CRC_INFO_MASK		PCB_FRAME_CRC_INFO_PRESENT
+
+#define NDLC_DUMP_SKB(info, skb)                                 \
+do {                                                             \
+	pr_debug("%s:\n", info);                                 \
+	print_hex_dump(KERN_DEBUG, "ndlc: ", DUMP_PREFIX_OFFSET, \
+			16, 1, skb->data, skb->len, 0);          \
+} while (0)
+
+int ndlc_open(struct llt_ndlc *ndlc)
+{
+	/* toggle reset pin */
+	ndlc->ops->enable(ndlc->phy_id);
+	return 0;
+}
+EXPORT_SYMBOL(ndlc_open);
+
+void ndlc_close(struct llt_ndlc *ndlc)
+{
+	/* toggle reset pin */
+	ndlc->ops->disable(ndlc->phy_id);
+}
+EXPORT_SYMBOL(ndlc_close);
+
+int ndlc_send(struct llt_ndlc *ndlc, struct sk_buff *skb)
+{
+	/* add ndlc header */
+	u8 pcb = PCB_TYPE_DATAFRAME | PCB_DATAFRAME_RETRANSMIT_NO |
+		PCB_FRAME_CRC_INFO_NOTPRESENT;
+
+	*skb_push(skb, 1) = pcb;
+	skb_queue_tail(&ndlc->send_q, skb);
+
+	schedule_work(&ndlc->sm_work);
+
+	return 0;
+}
+EXPORT_SYMBOL(ndlc_send);
+
+static void llt_ndlc_send_queue(struct llt_ndlc *ndlc)
+{
+	struct sk_buff *skb;
+	int r;
+	unsigned long time_sent;
+
+	if (ndlc->send_q.qlen)
+		pr_debug("sendQlen=%d unackQlen=%d\n",
+			 ndlc->send_q.qlen, ndlc->ack_pending_q.qlen);
+
+	while (ndlc->send_q.qlen) {
+		skb = skb_dequeue(&ndlc->send_q);
+		NDLC_DUMP_SKB("ndlc frame written", skb);
+		r = ndlc->ops->write(ndlc->phy_id, skb);
+		if (r < 0) {
+			ndlc->hard_fault = r;
+			break;
+		}
+		time_sent = jiffies;
+		*(unsigned long *)skb->cb = time_sent;
+
+		skb_queue_tail(&ndlc->ack_pending_q, skb);
+
+		/* start timer t1 for ndlc aknowledge */
+		ndlc->t1_active = true;
+		mod_timer(&ndlc->t1_timer, time_sent +
+			msecs_to_jiffies(NDLC_TIMER_T1));
+		/* start timer t2 for chip availability */
+		ndlc->t2_active = true;
+		mod_timer(&ndlc->t2_timer, time_sent +
+			msecs_to_jiffies(NDLC_TIMER_T2));
+	}
+}
+
+static void llt_ndlc_requeue_data_pending(struct llt_ndlc *ndlc)
+{
+	struct sk_buff *skb;
+	u8 pcb;
+
+	while ((skb = skb_dequeue_tail(&ndlc->ack_pending_q))) {
+		pcb = skb->data[0];
+		switch (pcb & PCB_TYPE_MASK) {
+		case PCB_TYPE_SUPERVISOR:
+			skb->data[0] = (pcb & ~PCB_SUPERVISOR_RETRANSMIT_MASK) |
+				PCB_SUPERVISOR_RETRANSMIT_YES;
+			break;
+		case PCB_TYPE_DATAFRAME:
+			skb->data[0] = (pcb & ~PCB_DATAFRAME_RETRANSMIT_MASK) |
+				PCB_DATAFRAME_RETRANSMIT_YES;
+			break;
+		default:
+			pr_err("UNKNOWN Packet Control Byte=%d\n", pcb);
+			kfree_skb(skb);
+			continue;
+		}
+		skb_queue_head(&ndlc->send_q, skb);
+	}
+}
+
+static void llt_ndlc_rcv_queue(struct llt_ndlc *ndlc)
+{
+	struct sk_buff *skb;
+	u8 pcb;
+	unsigned long time_sent;
+
+	if (ndlc->rcv_q.qlen)
+		pr_debug("rcvQlen=%d\n", ndlc->rcv_q.qlen);
+
+	while ((skb = skb_dequeue(&ndlc->rcv_q)) != NULL) {
+		pcb = skb->data[0];
+		skb_pull(skb, 1);
+		if ((pcb & PCB_TYPE_MASK) == PCB_TYPE_SUPERVISOR) {
+			switch (pcb & PCB_SYNC_MASK) {
+			case PCB_SYNC_ACK:
+				del_timer_sync(&ndlc->t1_timer);
+				del_timer_sync(&ndlc->t2_timer);
+				ndlc->t2_active = false;
+				ndlc->t1_active = false;
+				break;
+			case PCB_SYNC_NACK:
+				llt_ndlc_requeue_data_pending(ndlc);
+				llt_ndlc_send_queue(ndlc);
+				/* start timer t1 for ndlc aknowledge */
+				time_sent = jiffies;
+				ndlc->t1_active = true;
+				mod_timer(&ndlc->t1_timer, time_sent +
+					msecs_to_jiffies(NDLC_TIMER_T1));
+				break;
+			case PCB_SYNC_WAIT:
+				time_sent = jiffies;
+				ndlc->t1_active = true;
+				mod_timer(&ndlc->t1_timer, time_sent +
+					  msecs_to_jiffies(NDLC_TIMER_T1_WAIT));
+				break;
+			default:
+				pr_err("UNKNOWN Packet Control Byte=%d\n", pcb);
+				kfree_skb(skb);
+				break;
+			}
+		} else {
+			nci_recv_frame(ndlc->ndev, skb);
+		}
+	}
+}
+
+static void llt_ndlc_sm_work(struct work_struct *work)
+{
+	struct llt_ndlc *ndlc = container_of(work, struct llt_ndlc, sm_work);
+
+	llt_ndlc_send_queue(ndlc);
+	llt_ndlc_rcv_queue(ndlc);
+
+	if (ndlc->t1_active && timer_pending(&ndlc->t1_timer) == 0) {
+		pr_debug
+		    ("Handle T1(recv SUPERVISOR) elapsed (T1 now inactive)\n");
+		ndlc->t1_active = false;
+
+		llt_ndlc_requeue_data_pending(ndlc);
+		llt_ndlc_send_queue(ndlc);
+	}
+
+	if (ndlc->t2_active && timer_pending(&ndlc->t2_timer) == 0) {
+		pr_debug("Handle T2(recv DATA) elapsed (T2 now inactive)\n");
+		ndlc->t2_active = false;
+		ndlc->t1_active = false;
+		del_timer_sync(&ndlc->t1_timer);
+		del_timer_sync(&ndlc->t2_timer);
+		ndlc_close(ndlc);
+		ndlc->hard_fault = -EREMOTEIO;
+	}
+}
+
+void ndlc_recv(struct llt_ndlc *ndlc, struct sk_buff *skb)
+{
+	if (skb == NULL) {
+		pr_err("NULL Frame -> link is dead\n");
+		ndlc->hard_fault = -EREMOTEIO;
+		ndlc_close(ndlc);
+	} else {
+		NDLC_DUMP_SKB("incoming frame", skb);
+		skb_queue_tail(&ndlc->rcv_q, skb);
+	}
+
+	schedule_work(&ndlc->sm_work);
+}
+EXPORT_SYMBOL(ndlc_recv);
+
+static void ndlc_t1_timeout(unsigned long data)
+{
+	struct llt_ndlc *ndlc = (struct llt_ndlc *)data;
+
+	pr_debug("\n");
+
+	schedule_work(&ndlc->sm_work);
+}
+
+static void ndlc_t2_timeout(unsigned long data)
+{
+	struct llt_ndlc *ndlc = (struct llt_ndlc *)data;
+
+	pr_debug("\n");
+
+	schedule_work(&ndlc->sm_work);
+}
+
+int ndlc_probe(void *phy_id, struct nfc_phy_ops *phy_ops, struct device *dev,
+	       int phy_headroom, int phy_tailroom, struct llt_ndlc **ndlc_id)
+{
+	struct llt_ndlc *ndlc;
+
+	ndlc = devm_kzalloc(dev, sizeof(struct llt_ndlc), GFP_KERNEL);
+	if (!ndlc)
+		return -ENOMEM;
+
+	ndlc->ops = phy_ops;
+	ndlc->phy_id = phy_id;
+	ndlc->dev = dev;
+
+	*ndlc_id = ndlc;
+
+	/* initialize timers */
+	init_timer(&ndlc->t1_timer);
+	ndlc->t1_timer.data = (unsigned long)ndlc;
+	ndlc->t1_timer.function = ndlc_t1_timeout;
+
+	init_timer(&ndlc->t2_timer);
+	ndlc->t2_timer.data = (unsigned long)ndlc;
+	ndlc->t2_timer.function = ndlc_t2_timeout;
+
+	skb_queue_head_init(&ndlc->rcv_q);
+	skb_queue_head_init(&ndlc->send_q);
+	skb_queue_head_init(&ndlc->ack_pending_q);
+
+	INIT_WORK(&ndlc->sm_work, llt_ndlc_sm_work);
+
+	return st21nfcb_nci_probe(ndlc, phy_headroom, phy_tailroom);
+}
+EXPORT_SYMBOL(ndlc_probe);
+
+void ndlc_remove(struct llt_ndlc *ndlc)
+{
+	/* cancel timers */
+	del_timer_sync(&ndlc->t1_timer);
+	del_timer_sync(&ndlc->t2_timer);
+	ndlc->t2_active = false;
+	ndlc->t1_active = false;
+
+	skb_queue_purge(&ndlc->rcv_q);
+	skb_queue_purge(&ndlc->send_q);
+
+	st21nfcb_nci_remove(ndlc->ndev);
+}
+EXPORT_SYMBOL(ndlc_remove);