drivers/nfc/st-nci/ndlc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Low Level Transport (NDLC) Driver for STMicroelectronics NFC Chip
   4  *
   5  * Copyright (C) 2014-2015  STMicroelectronics SAS. All rights reserved.
   6  */
   7
   8 #include <linux/sched.h>
   9 #include <net/nfc/nci_core.h>
  10
  11 #include "st-nci.h"
  12
  13 #define NDLC_TIMER_T1           100
  14 #define NDLC_TIMER_T1_WAIT      400
  15 #define NDLC_TIMER_T2           1200
  16
  17 #define PCB_TYPE_DATAFRAME              0x80
  18 #define PCB_TYPE_SUPERVISOR             0xc0
  19 #define PCB_TYPE_MASK                   PCB_TYPE_SUPERVISOR
  20
  21 #define PCB_SYNC_ACK                    0x20
  22 #define PCB_SYNC_NACK                   0x10
  23 #define PCB_SYNC_WAIT                   0x30
  24 #define PCB_SYNC_NOINFO                 0x00
  25 #define PCB_SYNC_MASK                   PCB_SYNC_WAIT
  26
  27 #define PCB_DATAFRAME_RETRANSMIT_YES    0x00
  28 #define PCB_DATAFRAME_RETRANSMIT_NO     0x04
  29 #define PCB_DATAFRAME_RETRANSMIT_MASK   PCB_DATAFRAME_RETRANSMIT_NO
  30
  31 #define PCB_SUPERVISOR_RETRANSMIT_YES   0x00
  32 #define PCB_SUPERVISOR_RETRANSMIT_NO    0x02
  33 #define PCB_SUPERVISOR_RETRANSMIT_MASK  PCB_SUPERVISOR_RETRANSMIT_NO
  34
  35 #define PCB_FRAME_CRC_INFO_PRESENT      0x08
  36 #define PCB_FRAME_CRC_INFO_NOTPRESENT   0x00
  37 #define PCB_FRAME_CRC_INFO_MASK         PCB_FRAME_CRC_INFO_PRESENT
  38
  39 #define NDLC_DUMP_SKB(info, skb)                                 \
  40 do {                                                             \
  41         pr_debug("%s:\n", info);                                 \
  42         print_hex_dump(KERN_DEBUG, "ndlc: ", DUMP_PREFIX_OFFSET, \
  43                         16, 1, skb->data, skb->len, 0);          \
  44 } while (0)
  45
  46 int ndlc_open(struct llt_ndlc *ndlc)
  47 {
  48         /* toggle reset pin */
  49         ndlc->ops->enable(ndlc->phy_id);
  50         ndlc->powered = 1;
  51         return 0;
  52 }
  53 EXPORT_SYMBOL(ndlc_open);
  54
  55 void ndlc_close(struct llt_ndlc *ndlc)
  56 {
  57         struct nci_mode_set_cmd cmd;
  58
  59         cmd.cmd_type = ST_NCI_SET_NFC_MODE;
  60         cmd.mode = 0;
  61
  62         /* toggle reset pin */
  63         ndlc->ops->enable(ndlc->phy_id);
  64
  65         nci_prop_cmd(ndlc->ndev, ST_NCI_CORE_PROP,
  66                      sizeof(struct nci_mode_set_cmd), (__u8 *)&cmd);
  67
  68         ndlc->powered = 0;
  69         ndlc->ops->disable(ndlc->phy_id);
  70 }
  71 EXPORT_SYMBOL(ndlc_close);
  72
  73 int ndlc_send(struct llt_ndlc *ndlc, struct sk_buff *skb)
  74 {
  75         /* add ndlc header */
  76         u8 pcb = PCB_TYPE_DATAFRAME | PCB_DATAFRAME_RETRANSMIT_NO |
  77                 PCB_FRAME_CRC_INFO_NOTPRESENT;
  78
  79         *(u8 *)skb_push(skb, 1) = pcb;
  80         skb_queue_tail(&ndlc->send_q, skb);
  81
  82         schedule_work(&ndlc->sm_work);
  83
  84         return 0;
  85 }
  86 EXPORT_SYMBOL(ndlc_send);
  87
  88 static void llt_ndlc_send_queue(struct llt_ndlc *ndlc)
  89 {
  90         struct sk_buff *skb;
  91         int r;
  92         unsigned long time_sent;
  93
  94         if (ndlc->send_q.qlen)
  95                 pr_debug("sendQlen=%d unackQlen=%d\n",
  96                          ndlc->send_q.qlen, ndlc->ack_pending_q.qlen);
  97
  98         while (ndlc->send_q.qlen) {
  99                 skb = skb_dequeue(&ndlc->send_q);
 100                 NDLC_DUMP_SKB("ndlc frame written", skb);
 101                 r = ndlc->ops->write(ndlc->phy_id, skb);
 102                 if (r < 0) {
 103                         ndlc->hard_fault = r;
 104                         break;
 105                 }
 106                 time_sent = jiffies;
 107                 *(unsigned long *)skb->cb = time_sent;
 108
 109                 skb_queue_tail(&ndlc->ack_pending_q, skb);
 110
 111                 /* start timer t1 for ndlc aknowledge */
 112                 ndlc->t1_active = true;
 113                 mod_timer(&ndlc->t1_timer, time_sent +
 114                         msecs_to_jiffies(NDLC_TIMER_T1));
 115                 /* start timer t2 for chip availability */
 116                 ndlc->t2_active = true;
 117                 mod_timer(&ndlc->t2_timer, time_sent +
 118                         msecs_to_jiffies(NDLC_TIMER_T2));
 119         }
 120 }
 121
 122 static void llt_ndlc_requeue_data_pending(struct llt_ndlc *ndlc)
 123 {
 124         struct sk_buff *skb;
 125         u8 pcb;
 126
 127         while ((skb = skb_dequeue_tail(&ndlc->ack_pending_q))) {
 128                 pcb = skb->data[0];
 129                 switch (pcb & PCB_TYPE_MASK) {
 130                 case PCB_TYPE_SUPERVISOR:
 131                         skb->data[0] = (pcb & ~PCB_SUPERVISOR_RETRANSMIT_MASK) |
 132                                 PCB_SUPERVISOR_RETRANSMIT_YES;
 133                         break;
 134                 case PCB_TYPE_DATAFRAME:
 135                         skb->data[0] = (pcb & ~PCB_DATAFRAME_RETRANSMIT_MASK) |
 136                                 PCB_DATAFRAME_RETRANSMIT_YES;
 137                         break;
 138                 default:
 139                         pr_err("UNKNOWN Packet Control Byte=%d\n", pcb);
 140                         kfree_skb(skb);
 141                         continue;
 142                 }
 143                 skb_queue_head(&ndlc->send_q, skb);
 144         }
 145 }
 146
 147 static void llt_ndlc_rcv_queue(struct llt_ndlc *ndlc)
 148 {
 149         struct sk_buff *skb;
 150         u8 pcb;
 151         unsigned long time_sent;
 152
 153         if (ndlc->rcv_q.qlen)
 154                 pr_debug("rcvQlen=%d\n", ndlc->rcv_q.qlen);
 155
 156         while ((skb = skb_dequeue(&ndlc->rcv_q)) != NULL) {
 157                 pcb = skb->data[0];
 158                 skb_pull(skb, 1);
 159                 if ((pcb & PCB_TYPE_MASK) == PCB_TYPE_SUPERVISOR) {
 160                         switch (pcb & PCB_SYNC_MASK) {
 161                         case PCB_SYNC_ACK:
 162                                 skb = skb_dequeue(&ndlc->ack_pending_q);
 163                                 kfree_skb(skb);
 164                                 del_timer_sync(&ndlc->t1_timer);
 165                                 del_timer_sync(&ndlc->t2_timer);
 166                                 ndlc->t2_active = false;
 167                                 ndlc->t1_active = false;
 168                                 break;
 169                         case PCB_SYNC_NACK:
 170                                 llt_ndlc_requeue_data_pending(ndlc);
 171                                 llt_ndlc_send_queue(ndlc);
 172                                 /* start timer t1 for ndlc aknowledge */
 173                                 time_sent = jiffies;
 174                                 ndlc->t1_active = true;
 175                                 mod_timer(&ndlc->t1_timer, time_sent +
 176                                         msecs_to_jiffies(NDLC_TIMER_T1));
 177                                 break;
 178                         case PCB_SYNC_WAIT:
 179                                 time_sent = jiffies;
 180                                 ndlc->t1_active = true;
 181                                 mod_timer(&ndlc->t1_timer, time_sent +
 182                                           msecs_to_jiffies(NDLC_TIMER_T1_WAIT));
 183                                 break;
 184                         default:
 185                                 kfree_skb(skb);
 186                                 break;
 187                         }
 188                 } else if ((pcb & PCB_TYPE_MASK) == PCB_TYPE_DATAFRAME) {
 189                         nci_recv_frame(ndlc->ndev, skb);
 190                 } else {
 191                         kfree_skb(skb);
 192                 }
 193         }
 194 }
 195
 196 static void llt_ndlc_sm_work(struct work_struct *work)
 197 {
 198         struct llt_ndlc *ndlc = container_of(work, struct llt_ndlc, sm_work);
 199
 200         llt_ndlc_send_queue(ndlc);
 201         llt_ndlc_rcv_queue(ndlc);
 202
 203         if (ndlc->t1_active && timer_pending(&ndlc->t1_timer) == 0) {
 204                 pr_debug
 205                     ("Handle T1(recv SUPERVISOR) elapsed (T1 now inactive)\n");
 206                 ndlc->t1_active = false;
 207
 208                 llt_ndlc_requeue_data_pending(ndlc);
 209                 llt_ndlc_send_queue(ndlc);
 210         }
 211
 212         if (ndlc->t2_active && timer_pending(&ndlc->t2_timer) == 0) {
 213                 pr_debug("Handle T2(recv DATA) elapsed (T2 now inactive)\n");
 214                 ndlc->t2_active = false;
 215                 ndlc->t1_active = false;
 216                 del_timer_sync(&ndlc->t1_timer);
 217                 del_timer_sync(&ndlc->t2_timer);
 218                 ndlc_close(ndlc);
 219                 ndlc->hard_fault = -EREMOTEIO;
 220         }
 221 }
 222
 223 void ndlc_recv(struct llt_ndlc *ndlc, struct sk_buff *skb)
 224 {
 225         if (skb == NULL) {
 226                 pr_err("NULL Frame -> link is dead\n");
 227                 ndlc->hard_fault = -EREMOTEIO;
 228                 ndlc_close(ndlc);
 229         } else {
 230                 NDLC_DUMP_SKB("incoming frame", skb);
 231                 skb_queue_tail(&ndlc->rcv_q, skb);
 232         }
 233
 234         schedule_work(&ndlc->sm_work);
 235 }
 236 EXPORT_SYMBOL(ndlc_recv);
 237
 238 static void ndlc_t1_timeout(struct timer_list *t)
 239 {
 240         struct llt_ndlc *ndlc = from_timer(ndlc, t, t1_timer);
 241
 242         pr_debug("\n");
 243
 244         schedule_work(&ndlc->sm_work);
 245 }
 246
 247 static void ndlc_t2_timeout(struct timer_list *t)
 248 {
 249         struct llt_ndlc *ndlc = from_timer(ndlc, t, t2_timer);
 250
 251         pr_debug("\n");
 252
 253         schedule_work(&ndlc->sm_work);
 254 }
 255
 256 int ndlc_probe(void *phy_id, const struct nfc_phy_ops *phy_ops,
 257                struct device *dev, int phy_headroom, int phy_tailroom,
 258                struct llt_ndlc **ndlc_id, struct st_nci_se_status *se_status)
 259 {
 260         struct llt_ndlc *ndlc;
 261
 262         ndlc = devm_kzalloc(dev, sizeof(struct llt_ndlc), GFP_KERNEL);
 263         if (!ndlc)
 264                 return -ENOMEM;
 265
 266         ndlc->ops = phy_ops;
 267         ndlc->phy_id = phy_id;
 268         ndlc->dev = dev;
 269         ndlc->powered = 0;
 270
 271         *ndlc_id = ndlc;
 272
 273         /* initialize timers */
 274         timer_setup(&ndlc->t1_timer, ndlc_t1_timeout, 0);
 275         timer_setup(&ndlc->t2_timer, ndlc_t2_timeout, 0);
 276
 277         skb_queue_head_init(&ndlc->rcv_q);
 278         skb_queue_head_init(&ndlc->send_q);
 279         skb_queue_head_init(&ndlc->ack_pending_q);
 280
 281         INIT_WORK(&ndlc->sm_work, llt_ndlc_sm_work);
 282
 283         return st_nci_probe(ndlc, phy_headroom, phy_tailroom, se_status);
 284 }
 285 EXPORT_SYMBOL(ndlc_probe);
 286
 287 void ndlc_remove(struct llt_ndlc *ndlc)
 288 {
 289         st_nci_remove(ndlc->ndev);
 290
 291         /* cancel timers */
 292         del_timer_sync(&ndlc->t1_timer);
 293         del_timer_sync(&ndlc->t2_timer);
 294         ndlc->t2_active = false;
 295         ndlc->t1_active = false;
 296
 297         skb_queue_purge(&ndlc->rcv_q);
 298         skb_queue_purge(&ndlc->send_q);
 299 }
 300 EXPORT_SYMBOL(ndlc_remove);