1 /* 2 * Low Level Transport (NDLC) Driver for STMicroelectronics NFC Chip 3 * 4 * Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms and conditions of the GNU General Public License, 8 * version 2, as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, see <http://www.gnu.org/licenses/>. 17 */ 18 19 #include <linux/sched.h> 20 #include <net/nfc/nci_core.h> 21 22 #include "st-nci.h" 23 #include "ndlc.h" 24 25 #define NDLC_TIMER_T1 100 26 #define NDLC_TIMER_T1_WAIT 400 27 #define NDLC_TIMER_T2 1200 28 29 #define PCB_TYPE_DATAFRAME 0x80 30 #define PCB_TYPE_SUPERVISOR 0xc0 31 #define PCB_TYPE_MASK PCB_TYPE_SUPERVISOR 32 33 #define PCB_SYNC_ACK 0x20 34 #define PCB_SYNC_NACK 0x10 35 #define PCB_SYNC_WAIT 0x30 36 #define PCB_SYNC_NOINFO 0x00 37 #define PCB_SYNC_MASK PCB_SYNC_WAIT 38 39 #define PCB_DATAFRAME_RETRANSMIT_YES 0x00 40 #define PCB_DATAFRAME_RETRANSMIT_NO 0x04 41 #define PCB_DATAFRAME_RETRANSMIT_MASK PCB_DATAFRAME_RETRANSMIT_NO 42 43 #define PCB_SUPERVISOR_RETRANSMIT_YES 0x00 44 #define PCB_SUPERVISOR_RETRANSMIT_NO 0x02 45 #define PCB_SUPERVISOR_RETRANSMIT_MASK PCB_SUPERVISOR_RETRANSMIT_NO 46 47 #define PCB_FRAME_CRC_INFO_PRESENT 0x08 48 #define PCB_FRAME_CRC_INFO_NOTPRESENT 0x00 49 #define PCB_FRAME_CRC_INFO_MASK PCB_FRAME_CRC_INFO_PRESENT 50 51 #define NDLC_DUMP_SKB(info, skb) \ 52 do { \ 53 pr_debug("%s:\n", info); \ 54 print_hex_dump(KERN_DEBUG, "ndlc: ", DUMP_PREFIX_OFFSET, \ 55 16, 1, skb->data, skb->len, 0); \ 56 } while (0) 57 58 int ndlc_open(struct llt_ndlc *ndlc) 59 { 60 /* toggle reset pin */ 61 ndlc->ops->enable(ndlc->phy_id); 62 ndlc->powered = 1; 63 return 0; 64 } 65 EXPORT_SYMBOL(ndlc_open); 66 67 void ndlc_close(struct llt_ndlc *ndlc) 68 { 69 struct nci_mode_set_cmd cmd; 70 71 cmd.cmd_type = ST_NCI_SET_NFC_MODE; 72 cmd.mode = 0; 73 74 /* toggle reset pin */ 75 ndlc->ops->enable(ndlc->phy_id); 76 77 nci_prop_cmd(ndlc->ndev, ST_NCI_CORE_PROP, 78 sizeof(struct nci_mode_set_cmd), (__u8 *)&cmd); 79 80 ndlc->powered = 0; 81 ndlc->ops->disable(ndlc->phy_id); 82 } 83 EXPORT_SYMBOL(ndlc_close); 84 85 int ndlc_send(struct llt_ndlc *ndlc, struct sk_buff *skb) 86 { 87 /* add ndlc header */ 88 u8 pcb = PCB_TYPE_DATAFRAME | PCB_DATAFRAME_RETRANSMIT_NO | 89 PCB_FRAME_CRC_INFO_NOTPRESENT; 90 91 *skb_push(skb, 1) = pcb; 92 skb_queue_tail(&ndlc->send_q, skb); 93 94 schedule_work(&ndlc->sm_work); 95 96 return 0; 97 } 98 EXPORT_SYMBOL(ndlc_send); 99 100 static void llt_ndlc_send_queue(struct llt_ndlc *ndlc) 101 { 102 struct sk_buff *skb; 103 int r; 104 unsigned long time_sent; 105 106 if (ndlc->send_q.qlen) 107 pr_debug("sendQlen=%d unackQlen=%d\n", 108 ndlc->send_q.qlen, ndlc->ack_pending_q.qlen); 109 110 while (ndlc->send_q.qlen) { 111 skb = skb_dequeue(&ndlc->send_q); 112 NDLC_DUMP_SKB("ndlc frame written", skb); 113 r = ndlc->ops->write(ndlc->phy_id, skb); 114 if (r < 0) { 115 ndlc->hard_fault = r; 116 break; 117 } 118 time_sent = jiffies; 119 *(unsigned long *)skb->cb = time_sent; 120 121 skb_queue_tail(&ndlc->ack_pending_q, skb); 122 123 /* start timer t1 for ndlc aknowledge */ 124 ndlc->t1_active = true; 125 mod_timer(&ndlc->t1_timer, time_sent + 126 msecs_to_jiffies(NDLC_TIMER_T1)); 127 /* start timer t2 for chip availability */ 128 ndlc->t2_active = true; 129 mod_timer(&ndlc->t2_timer, time_sent + 130 msecs_to_jiffies(NDLC_TIMER_T2)); 131 } 132 } 133 134 static void llt_ndlc_requeue_data_pending(struct llt_ndlc *ndlc) 135 { 136 struct sk_buff *skb; 137 u8 pcb; 138 139 while ((skb = skb_dequeue_tail(&ndlc->ack_pending_q))) { 140 pcb = skb->data[0]; 141 switch (pcb & PCB_TYPE_MASK) { 142 case PCB_TYPE_SUPERVISOR: 143 skb->data[0] = (pcb & ~PCB_SUPERVISOR_RETRANSMIT_MASK) | 144 PCB_SUPERVISOR_RETRANSMIT_YES; 145 break; 146 case PCB_TYPE_DATAFRAME: 147 skb->data[0] = (pcb & ~PCB_DATAFRAME_RETRANSMIT_MASK) | 148 PCB_DATAFRAME_RETRANSMIT_YES; 149 break; 150 default: 151 pr_err("UNKNOWN Packet Control Byte=%d\n", pcb); 152 kfree_skb(skb); 153 continue; 154 } 155 skb_queue_head(&ndlc->send_q, skb); 156 } 157 } 158 159 static void llt_ndlc_rcv_queue(struct llt_ndlc *ndlc) 160 { 161 struct sk_buff *skb; 162 u8 pcb; 163 unsigned long time_sent; 164 165 if (ndlc->rcv_q.qlen) 166 pr_debug("rcvQlen=%d\n", ndlc->rcv_q.qlen); 167 168 while ((skb = skb_dequeue(&ndlc->rcv_q)) != NULL) { 169 pcb = skb->data[0]; 170 skb_pull(skb, 1); 171 if ((pcb & PCB_TYPE_MASK) == PCB_TYPE_SUPERVISOR) { 172 switch (pcb & PCB_SYNC_MASK) { 173 case PCB_SYNC_ACK: 174 skb = skb_dequeue(&ndlc->ack_pending_q); 175 kfree_skb(skb); 176 del_timer_sync(&ndlc->t1_timer); 177 del_timer_sync(&ndlc->t2_timer); 178 ndlc->t2_active = false; 179 ndlc->t1_active = false; 180 break; 181 case PCB_SYNC_NACK: 182 llt_ndlc_requeue_data_pending(ndlc); 183 llt_ndlc_send_queue(ndlc); 184 /* start timer t1 for ndlc aknowledge */ 185 time_sent = jiffies; 186 ndlc->t1_active = true; 187 mod_timer(&ndlc->t1_timer, time_sent + 188 msecs_to_jiffies(NDLC_TIMER_T1)); 189 break; 190 case PCB_SYNC_WAIT: 191 time_sent = jiffies; 192 ndlc->t1_active = true; 193 mod_timer(&ndlc->t1_timer, time_sent + 194 msecs_to_jiffies(NDLC_TIMER_T1_WAIT)); 195 break; 196 default: 197 kfree_skb(skb); 198 break; 199 } 200 } else if ((pcb & PCB_TYPE_MASK) == PCB_TYPE_DATAFRAME) { 201 nci_recv_frame(ndlc->ndev, skb); 202 } else { 203 kfree_skb(skb); 204 } 205 } 206 } 207 208 static void llt_ndlc_sm_work(struct work_struct *work) 209 { 210 struct llt_ndlc *ndlc = container_of(work, struct llt_ndlc, sm_work); 211 212 llt_ndlc_send_queue(ndlc); 213 llt_ndlc_rcv_queue(ndlc); 214 215 if (ndlc->t1_active && timer_pending(&ndlc->t1_timer) == 0) { 216 pr_debug 217 ("Handle T1(recv SUPERVISOR) elapsed (T1 now inactive)\n"); 218 ndlc->t1_active = false; 219 220 llt_ndlc_requeue_data_pending(ndlc); 221 llt_ndlc_send_queue(ndlc); 222 } 223 224 if (ndlc->t2_active && timer_pending(&ndlc->t2_timer) == 0) { 225 pr_debug("Handle T2(recv DATA) elapsed (T2 now inactive)\n"); 226 ndlc->t2_active = false; 227 ndlc->t1_active = false; 228 del_timer_sync(&ndlc->t1_timer); 229 del_timer_sync(&ndlc->t2_timer); 230 ndlc_close(ndlc); 231 ndlc->hard_fault = -EREMOTEIO; 232 } 233 } 234 235 void ndlc_recv(struct llt_ndlc *ndlc, struct sk_buff *skb) 236 { 237 if (skb == NULL) { 238 pr_err("NULL Frame -> link is dead\n"); 239 ndlc->hard_fault = -EREMOTEIO; 240 ndlc_close(ndlc); 241 } else { 242 NDLC_DUMP_SKB("incoming frame", skb); 243 skb_queue_tail(&ndlc->rcv_q, skb); 244 } 245 246 schedule_work(&ndlc->sm_work); 247 } 248 EXPORT_SYMBOL(ndlc_recv); 249 250 static void ndlc_t1_timeout(unsigned long data) 251 { 252 struct llt_ndlc *ndlc = (struct llt_ndlc *)data; 253 254 pr_debug("\n"); 255 256 schedule_work(&ndlc->sm_work); 257 } 258 259 static void ndlc_t2_timeout(unsigned long data) 260 { 261 struct llt_ndlc *ndlc = (struct llt_ndlc *)data; 262 263 pr_debug("\n"); 264 265 schedule_work(&ndlc->sm_work); 266 } 267 268 int ndlc_probe(void *phy_id, struct nfc_phy_ops *phy_ops, struct device *dev, 269 int phy_headroom, int phy_tailroom, struct llt_ndlc **ndlc_id, 270 struct st_nci_se_status *se_status) 271 { 272 struct llt_ndlc *ndlc; 273 274 ndlc = devm_kzalloc(dev, sizeof(struct llt_ndlc), GFP_KERNEL); 275 if (!ndlc) 276 return -ENOMEM; 277 278 ndlc->ops = phy_ops; 279 ndlc->phy_id = phy_id; 280 ndlc->dev = dev; 281 ndlc->powered = 0; 282 283 *ndlc_id = ndlc; 284 285 /* initialize timers */ 286 init_timer(&ndlc->t1_timer); 287 ndlc->t1_timer.data = (unsigned long)ndlc; 288 ndlc->t1_timer.function = ndlc_t1_timeout; 289 290 init_timer(&ndlc->t2_timer); 291 ndlc->t2_timer.data = (unsigned long)ndlc; 292 ndlc->t2_timer.function = ndlc_t2_timeout; 293 294 skb_queue_head_init(&ndlc->rcv_q); 295 skb_queue_head_init(&ndlc->send_q); 296 skb_queue_head_init(&ndlc->ack_pending_q); 297 298 INIT_WORK(&ndlc->sm_work, llt_ndlc_sm_work); 299 300 return st_nci_probe(ndlc, phy_headroom, phy_tailroom, se_status); 301 } 302 EXPORT_SYMBOL(ndlc_probe); 303 304 void ndlc_remove(struct llt_ndlc *ndlc) 305 { 306 st_nci_remove(ndlc->ndev); 307 308 /* cancel timers */ 309 del_timer_sync(&ndlc->t1_timer); 310 del_timer_sync(&ndlc->t2_timer); 311 ndlc->t2_active = false; 312 ndlc->t1_active = false; 313 314 skb_queue_purge(&ndlc->rcv_q); 315 skb_queue_purge(&ndlc->send_q); 316 } 317 EXPORT_SYMBOL(ndlc_remove); 318