// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Low Level Transport (NDLC) Driver for STMicroelectronics NFC Chip
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*
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* Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved.
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*/
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#include <linux/sched.h>
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#include <net/nfc/nci_core.h>
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#include "st-nci.h"
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#define NDLC_TIMER_T1 100
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#define NDLC_TIMER_T1_WAIT 400
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#define NDLC_TIMER_T2 1200
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#define PCB_TYPE_DATAFRAME 0x80
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#define PCB_TYPE_SUPERVISOR 0xc0
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#define PCB_TYPE_MASK PCB_TYPE_SUPERVISOR
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#define PCB_SYNC_ACK 0x20
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#define PCB_SYNC_NACK 0x10
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#define PCB_SYNC_WAIT 0x30
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#define PCB_SYNC_NOINFO 0x00
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#define PCB_SYNC_MASK PCB_SYNC_WAIT
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#define PCB_DATAFRAME_RETRANSMIT_YES 0x00
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#define PCB_DATAFRAME_RETRANSMIT_NO 0x04
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#define PCB_DATAFRAME_RETRANSMIT_MASK PCB_DATAFRAME_RETRANSMIT_NO
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#define PCB_SUPERVISOR_RETRANSMIT_YES 0x00
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#define PCB_SUPERVISOR_RETRANSMIT_NO 0x02
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#define PCB_SUPERVISOR_RETRANSMIT_MASK PCB_SUPERVISOR_RETRANSMIT_NO
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#define PCB_FRAME_CRC_INFO_PRESENT 0x08
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#define PCB_FRAME_CRC_INFO_NOTPRESENT 0x00
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#define PCB_FRAME_CRC_INFO_MASK PCB_FRAME_CRC_INFO_PRESENT
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#define NDLC_DUMP_SKB(info, skb) \
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do { \
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pr_debug("%s:\n", info); \
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print_hex_dump(KERN_DEBUG, "ndlc: ", DUMP_PREFIX_OFFSET, \
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16, 1, skb->data, skb->len, 0); \
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} while (0)
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int ndlc_open(struct llt_ndlc *ndlc)
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{
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/* toggle reset pin */
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ndlc->ops->enable(ndlc->phy_id);
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ndlc->powered = 1;
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return 0;
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}
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EXPORT_SYMBOL(ndlc_open);
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void ndlc_close(struct llt_ndlc *ndlc)
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{
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struct nci_mode_set_cmd cmd;
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cmd.cmd_type = ST_NCI_SET_NFC_MODE;
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cmd.mode = 0;
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/* toggle reset pin */
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ndlc->ops->enable(ndlc->phy_id);
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nci_prop_cmd(ndlc->ndev, ST_NCI_CORE_PROP,
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sizeof(struct nci_mode_set_cmd), (__u8 *)&cmd);
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ndlc->powered = 0;
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ndlc->ops->disable(ndlc->phy_id);
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}
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EXPORT_SYMBOL(ndlc_close);
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int ndlc_send(struct llt_ndlc *ndlc, struct sk_buff *skb)
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{
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/* add ndlc header */
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u8 pcb = PCB_TYPE_DATAFRAME | PCB_DATAFRAME_RETRANSMIT_NO |
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PCB_FRAME_CRC_INFO_NOTPRESENT;
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*(u8 *)skb_push(skb, 1) = pcb;
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skb_queue_tail(&ndlc->send_q, skb);
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schedule_work(&ndlc->sm_work);
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return 0;
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}
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EXPORT_SYMBOL(ndlc_send);
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static void llt_ndlc_send_queue(struct llt_ndlc *ndlc)
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{
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struct sk_buff *skb;
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int r;
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unsigned long time_sent;
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if (ndlc->send_q.qlen)
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pr_debug("sendQlen=%d unackQlen=%d\n",
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ndlc->send_q.qlen, ndlc->ack_pending_q.qlen);
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while (ndlc->send_q.qlen) {
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skb = skb_dequeue(&ndlc->send_q);
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NDLC_DUMP_SKB("ndlc frame written", skb);
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r = ndlc->ops->write(ndlc->phy_id, skb);
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if (r < 0) {
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ndlc->hard_fault = r;
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break;
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}
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time_sent = jiffies;
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*(unsigned long *)skb->cb = time_sent;
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skb_queue_tail(&ndlc->ack_pending_q, skb);
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/* start timer t1 for ndlc aknowledge */
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ndlc->t1_active = true;
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mod_timer(&ndlc->t1_timer, time_sent +
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msecs_to_jiffies(NDLC_TIMER_T1));
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/* start timer t2 for chip availability */
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ndlc->t2_active = true;
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mod_timer(&ndlc->t2_timer, time_sent +
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msecs_to_jiffies(NDLC_TIMER_T2));
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}
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}
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static void llt_ndlc_requeue_data_pending(struct llt_ndlc *ndlc)
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{
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struct sk_buff *skb;
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u8 pcb;
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while ((skb = skb_dequeue_tail(&ndlc->ack_pending_q))) {
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pcb = skb->data[0];
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switch (pcb & PCB_TYPE_MASK) {
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case PCB_TYPE_SUPERVISOR:
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skb->data[0] = (pcb & ~PCB_SUPERVISOR_RETRANSMIT_MASK) |
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PCB_SUPERVISOR_RETRANSMIT_YES;
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break;
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case PCB_TYPE_DATAFRAME:
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skb->data[0] = (pcb & ~PCB_DATAFRAME_RETRANSMIT_MASK) |
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PCB_DATAFRAME_RETRANSMIT_YES;
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break;
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default:
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pr_err("UNKNOWN Packet Control Byte=%d\n", pcb);
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kfree_skb(skb);
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continue;
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}
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skb_queue_head(&ndlc->send_q, skb);
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}
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}
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static void llt_ndlc_rcv_queue(struct llt_ndlc *ndlc)
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{
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struct sk_buff *skb;
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u8 pcb;
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unsigned long time_sent;
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if (ndlc->rcv_q.qlen)
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pr_debug("rcvQlen=%d\n", ndlc->rcv_q.qlen);
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while ((skb = skb_dequeue(&ndlc->rcv_q)) != NULL) {
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pcb = skb->data[0];
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skb_pull(skb, 1);
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if ((pcb & PCB_TYPE_MASK) == PCB_TYPE_SUPERVISOR) {
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switch (pcb & PCB_SYNC_MASK) {
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case PCB_SYNC_ACK:
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skb = skb_dequeue(&ndlc->ack_pending_q);
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kfree_skb(skb);
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del_timer_sync(&ndlc->t1_timer);
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del_timer_sync(&ndlc->t2_timer);
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ndlc->t2_active = false;
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ndlc->t1_active = false;
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break;
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case PCB_SYNC_NACK:
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llt_ndlc_requeue_data_pending(ndlc);
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llt_ndlc_send_queue(ndlc);
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/* start timer t1 for ndlc aknowledge */
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time_sent = jiffies;
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ndlc->t1_active = true;
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mod_timer(&ndlc->t1_timer, time_sent +
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msecs_to_jiffies(NDLC_TIMER_T1));
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break;
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case PCB_SYNC_WAIT:
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time_sent = jiffies;
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ndlc->t1_active = true;
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mod_timer(&ndlc->t1_timer, time_sent +
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msecs_to_jiffies(NDLC_TIMER_T1_WAIT));
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break;
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default:
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kfree_skb(skb);
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break;
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}
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} else if ((pcb & PCB_TYPE_MASK) == PCB_TYPE_DATAFRAME) {
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nci_recv_frame(ndlc->ndev, skb);
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} else {
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kfree_skb(skb);
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}
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}
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}
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static void llt_ndlc_sm_work(struct work_struct *work)
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{
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struct llt_ndlc *ndlc = container_of(work, struct llt_ndlc, sm_work);
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llt_ndlc_send_queue(ndlc);
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llt_ndlc_rcv_queue(ndlc);
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if (ndlc->t1_active && timer_pending(&ndlc->t1_timer) == 0) {
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pr_debug
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("Handle T1(recv SUPERVISOR) elapsed (T1 now inactive)\n");
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ndlc->t1_active = false;
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llt_ndlc_requeue_data_pending(ndlc);
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llt_ndlc_send_queue(ndlc);
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}
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if (ndlc->t2_active && timer_pending(&ndlc->t2_timer) == 0) {
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pr_debug("Handle T2(recv DATA) elapsed (T2 now inactive)\n");
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ndlc->t2_active = false;
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ndlc->t1_active = false;
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del_timer_sync(&ndlc->t1_timer);
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del_timer_sync(&ndlc->t2_timer);
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ndlc_close(ndlc);
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ndlc->hard_fault = -EREMOTEIO;
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}
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}
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void ndlc_recv(struct llt_ndlc *ndlc, struct sk_buff *skb)
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{
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if (skb == NULL) {
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pr_err("NULL Frame -> link is dead\n");
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ndlc->hard_fault = -EREMOTEIO;
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ndlc_close(ndlc);
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} else {
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NDLC_DUMP_SKB("incoming frame", skb);
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skb_queue_tail(&ndlc->rcv_q, skb);
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}
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schedule_work(&ndlc->sm_work);
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}
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EXPORT_SYMBOL(ndlc_recv);
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static void ndlc_t1_timeout(struct timer_list *t)
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{
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struct llt_ndlc *ndlc = from_timer(ndlc, t, t1_timer);
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pr_debug("\n");
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schedule_work(&ndlc->sm_work);
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}
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static void ndlc_t2_timeout(struct timer_list *t)
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{
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struct llt_ndlc *ndlc = from_timer(ndlc, t, t2_timer);
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pr_debug("\n");
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schedule_work(&ndlc->sm_work);
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}
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int ndlc_probe(void *phy_id, struct nfc_phy_ops *phy_ops, struct device *dev,
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int phy_headroom, int phy_tailroom, struct llt_ndlc **ndlc_id,
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struct st_nci_se_status *se_status)
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{
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struct llt_ndlc *ndlc;
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ndlc = devm_kzalloc(dev, sizeof(struct llt_ndlc), GFP_KERNEL);
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if (!ndlc)
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return -ENOMEM;
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ndlc->ops = phy_ops;
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ndlc->phy_id = phy_id;
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ndlc->dev = dev;
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ndlc->powered = 0;
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*ndlc_id = ndlc;
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/* initialize timers */
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timer_setup(&ndlc->t1_timer, ndlc_t1_timeout, 0);
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timer_setup(&ndlc->t2_timer, ndlc_t2_timeout, 0);
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skb_queue_head_init(&ndlc->rcv_q);
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skb_queue_head_init(&ndlc->send_q);
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skb_queue_head_init(&ndlc->ack_pending_q);
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INIT_WORK(&ndlc->sm_work, llt_ndlc_sm_work);
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return st_nci_probe(ndlc, phy_headroom, phy_tailroom, se_status);
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}
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EXPORT_SYMBOL(ndlc_probe);
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void ndlc_remove(struct llt_ndlc *ndlc)
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{
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/* cancel timers */
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del_timer_sync(&ndlc->t1_timer);
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del_timer_sync(&ndlc->t2_timer);
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ndlc->t2_active = false;
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ndlc->t1_active = false;
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/* cancel work */
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cancel_work_sync(&ndlc->sm_work);
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st_nci_remove(ndlc->ndev);
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skb_queue_purge(&ndlc->rcv_q);
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skb_queue_purge(&ndlc->send_q);
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}
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EXPORT_SYMBOL(ndlc_remove);
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