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 24 #define NDLC_TIMER_T1 100 25 #define NDLC_TIMER_T1_WAIT 400 26 #define NDLC_TIMER_T2 1200 27 28 #define PCB_TYPE_DATAFRAME 0x80 29 #define PCB_TYPE_SUPERVISOR 0xc0 30 #define PCB_TYPE_MASK PCB_TYPE_SUPERVISOR 31 32 #define PCB_SYNC_ACK 0x20 33 #define PCB_SYNC_NACK 0x10 34 #define PCB_SYNC_WAIT 0x30 35 #define PCB_SYNC_NOINFO 0x00 36 #define PCB_SYNC_MASK PCB_SYNC_WAIT 37 38 #define PCB_DATAFRAME_RETRANSMIT_YES 0x00 39 #define PCB_DATAFRAME_RETRANSMIT_NO 0x04 40 #define PCB_DATAFRAME_RETRANSMIT_MASK PCB_DATAFRAME_RETRANSMIT_NO 41 42 #define PCB_SUPERVISOR_RETRANSMIT_YES 0x00 43 #define PCB_SUPERVISOR_RETRANSMIT_NO 0x02 44 #define PCB_SUPERVISOR_RETRANSMIT_MASK PCB_SUPERVISOR_RETRANSMIT_NO 45 46 #define PCB_FRAME_CRC_INFO_PRESENT 0x08 47 #define PCB_FRAME_CRC_INFO_NOTPRESENT 0x00 48 #define PCB_FRAME_CRC_INFO_MASK PCB_FRAME_CRC_INFO_PRESENT 49 50 #define NDLC_DUMP_SKB(info, skb) \ 51 do { \ 52 pr_debug("%s:\n", info); \ 53 print_hex_dump(KERN_DEBUG, "ndlc: ", DUMP_PREFIX_OFFSET, \ 54 16, 1, skb->data, skb->len, 0); \ 55 } while (0) 56 57 int ndlc_open(struct llt_ndlc *ndlc) 58 { 59 /* toggle reset pin */ 60 ndlc->ops->enable(ndlc->phy_id); 61 ndlc->powered = 1; 62 return 0; 63 } 64 EXPORT_SYMBOL(ndlc_open); 65 66 void ndlc_close(struct llt_ndlc *ndlc) 67 { 68 struct nci_mode_set_cmd cmd; 69 70 cmd.cmd_type = ST_NCI_SET_NFC_MODE; 71 cmd.mode = 0; 72 73 /* toggle reset pin */ 74 ndlc->ops->enable(ndlc->phy_id); 75 76 nci_prop_cmd(ndlc->ndev, ST_NCI_CORE_PROP, 77 sizeof(struct nci_mode_set_cmd), (__u8 *)&cmd); 78 79 ndlc->powered = 0; 80 ndlc->ops->disable(ndlc->phy_id); 81 } 82 EXPORT_SYMBOL(ndlc_close); 83 84 int ndlc_send(struct llt_ndlc *ndlc, struct sk_buff *skb) 85 { 86 /* add ndlc header */ 87 u8 pcb = PCB_TYPE_DATAFRAME | PCB_DATAFRAME_RETRANSMIT_NO | 88 PCB_FRAME_CRC_INFO_NOTPRESENT; 89 90 *skb_push(skb, 1) = pcb; 91 skb_queue_tail(&ndlc->send_q, skb); 92 93 schedule_work(&ndlc->sm_work); 94 95 return 0; 96 } 97 EXPORT_SYMBOL(ndlc_send); 98 99 static void llt_ndlc_send_queue(struct llt_ndlc *ndlc) 100 { 101 struct sk_buff *skb; 102 int r; 103 unsigned long time_sent; 104 105 if (ndlc->send_q.qlen) 106 pr_debug("sendQlen=%d unackQlen=%d\n", 107 ndlc->send_q.qlen, ndlc->ack_pending_q.qlen); 108 109 while (ndlc->send_q.qlen) { 110 skb = skb_dequeue(&ndlc->send_q); 111 NDLC_DUMP_SKB("ndlc frame written", skb); 112 r = ndlc->ops->write(ndlc->phy_id, skb); 113 if (r < 0) { 114 ndlc->hard_fault = r; 115 break; 116 } 117 time_sent = jiffies; 118 *(unsigned long *)skb->cb = time_sent; 119 120 skb_queue_tail(&ndlc->ack_pending_q, skb); 121 122 /* start timer t1 for ndlc aknowledge */ 123 ndlc->t1_active = true; 124 mod_timer(&ndlc->t1_timer, time_sent + 125 msecs_to_jiffies(NDLC_TIMER_T1)); 126 /* start timer t2 for chip availability */ 127 ndlc->t2_active = true; 128 mod_timer(&ndlc->t2_timer, time_sent + 129 msecs_to_jiffies(NDLC_TIMER_T2)); 130 } 131 } 132 133 static void llt_ndlc_requeue_data_pending(struct llt_ndlc *ndlc) 134 { 135 struct sk_buff *skb; 136 u8 pcb; 137 138 while ((skb = skb_dequeue_tail(&ndlc->ack_pending_q))) { 139 pcb = skb->data[0]; 140 switch (pcb & PCB_TYPE_MASK) { 141 case PCB_TYPE_SUPERVISOR: 142 skb->data[0] = (pcb & ~PCB_SUPERVISOR_RETRANSMIT_MASK) | 143 PCB_SUPERVISOR_RETRANSMIT_YES; 144 break; 145 case PCB_TYPE_DATAFRAME: 146 skb->data[0] = (pcb & ~PCB_DATAFRAME_RETRANSMIT_MASK) | 147 PCB_DATAFRAME_RETRANSMIT_YES; 148 break; 149 default: 150 pr_err("UNKNOWN Packet Control Byte=%d\n", pcb); 151 kfree_skb(skb); 152 continue; 153 } 154 skb_queue_head(&ndlc->send_q, skb); 155 } 156 } 157 158 static void llt_ndlc_rcv_queue(struct llt_ndlc *ndlc) 159 { 160 struct sk_buff *skb; 161 u8 pcb; 162 unsigned long time_sent; 163 164 if (ndlc->rcv_q.qlen) 165 pr_debug("rcvQlen=%d\n", ndlc->rcv_q.qlen); 166 167 while ((skb = skb_dequeue(&ndlc->rcv_q)) != NULL) { 168 pcb = skb->data[0]; 169 skb_pull(skb, 1); 170 if ((pcb & PCB_TYPE_MASK) == PCB_TYPE_SUPERVISOR) { 171 switch (pcb & PCB_SYNC_MASK) { 172 case PCB_SYNC_ACK: 173 skb = skb_dequeue(&ndlc->ack_pending_q); 174 kfree_skb(skb); 175 del_timer_sync(&ndlc->t1_timer); 176 del_timer_sync(&ndlc->t2_timer); 177 ndlc->t2_active = false; 178 ndlc->t1_active = false; 179 break; 180 case PCB_SYNC_NACK: 181 llt_ndlc_requeue_data_pending(ndlc); 182 llt_ndlc_send_queue(ndlc); 183 /* start timer t1 for ndlc aknowledge */ 184 time_sent = jiffies; 185 ndlc->t1_active = true; 186 mod_timer(&ndlc->t1_timer, time_sent + 187 msecs_to_jiffies(NDLC_TIMER_T1)); 188 break; 189 case PCB_SYNC_WAIT: 190 time_sent = jiffies; 191 ndlc->t1_active = true; 192 mod_timer(&ndlc->t1_timer, time_sent + 193 msecs_to_jiffies(NDLC_TIMER_T1_WAIT)); 194 break; 195 default: 196 kfree_skb(skb); 197 break; 198 } 199 } else if ((pcb & PCB_TYPE_MASK) == PCB_TYPE_DATAFRAME) { 200 nci_recv_frame(ndlc->ndev, skb); 201 } else { 202 kfree_skb(skb); 203 } 204 } 205 } 206 207 static void llt_ndlc_sm_work(struct work_struct *work) 208 { 209 struct llt_ndlc *ndlc = container_of(work, struct llt_ndlc, sm_work); 210 211 llt_ndlc_send_queue(ndlc); 212 llt_ndlc_rcv_queue(ndlc); 213 214 if (ndlc->t1_active && timer_pending(&ndlc->t1_timer) == 0) { 215 pr_debug 216 ("Handle T1(recv SUPERVISOR) elapsed (T1 now inactive)\n"); 217 ndlc->t1_active = false; 218 219 llt_ndlc_requeue_data_pending(ndlc); 220 llt_ndlc_send_queue(ndlc); 221 } 222 223 if (ndlc->t2_active && timer_pending(&ndlc->t2_timer) == 0) { 224 pr_debug("Handle T2(recv DATA) elapsed (T2 now inactive)\n"); 225 ndlc->t2_active = false; 226 ndlc->t1_active = false; 227 del_timer_sync(&ndlc->t1_timer); 228 del_timer_sync(&ndlc->t2_timer); 229 ndlc_close(ndlc); 230 ndlc->hard_fault = -EREMOTEIO; 231 } 232 } 233 234 void ndlc_recv(struct llt_ndlc *ndlc, struct sk_buff *skb) 235 { 236 if (skb == NULL) { 237 pr_err("NULL Frame -> link is dead\n"); 238 ndlc->hard_fault = -EREMOTEIO; 239 ndlc_close(ndlc); 240 } else { 241 NDLC_DUMP_SKB("incoming frame", skb); 242 skb_queue_tail(&ndlc->rcv_q, skb); 243 } 244 245 schedule_work(&ndlc->sm_work); 246 } 247 EXPORT_SYMBOL(ndlc_recv); 248 249 static void ndlc_t1_timeout(unsigned long data) 250 { 251 struct llt_ndlc *ndlc = (struct llt_ndlc *)data; 252 253 pr_debug("\n"); 254 255 schedule_work(&ndlc->sm_work); 256 } 257 258 static void ndlc_t2_timeout(unsigned long data) 259 { 260 struct llt_ndlc *ndlc = (struct llt_ndlc *)data; 261 262 pr_debug("\n"); 263 264 schedule_work(&ndlc->sm_work); 265 } 266 267 int ndlc_probe(void *phy_id, struct nfc_phy_ops *phy_ops, struct device *dev, 268 int phy_headroom, int phy_tailroom, struct llt_ndlc **ndlc_id, 269 struct st_nci_se_status *se_status) 270 { 271 struct llt_ndlc *ndlc; 272 273 ndlc = devm_kzalloc(dev, sizeof(struct llt_ndlc), GFP_KERNEL); 274 if (!ndlc) 275 return -ENOMEM; 276 277 ndlc->ops = phy_ops; 278 ndlc->phy_id = phy_id; 279 ndlc->dev = dev; 280 ndlc->powered = 0; 281 282 *ndlc_id = ndlc; 283 284 /* initialize timers */ 285 init_timer(&ndlc->t1_timer); 286 ndlc->t1_timer.data = (unsigned long)ndlc; 287 ndlc->t1_timer.function = ndlc_t1_timeout; 288 289 init_timer(&ndlc->t2_timer); 290 ndlc->t2_timer.data = (unsigned long)ndlc; 291 ndlc->t2_timer.function = ndlc_t2_timeout; 292 293 skb_queue_head_init(&ndlc->rcv_q); 294 skb_queue_head_init(&ndlc->send_q); 295 skb_queue_head_init(&ndlc->ack_pending_q); 296 297 INIT_WORK(&ndlc->sm_work, llt_ndlc_sm_work); 298 299 return st_nci_probe(ndlc, phy_headroom, phy_tailroom, se_status); 300 } 301 EXPORT_SYMBOL(ndlc_probe); 302 303 void ndlc_remove(struct llt_ndlc *ndlc) 304 { 305 st_nci_remove(ndlc->ndev); 306 307 /* cancel timers */ 308 del_timer_sync(&ndlc->t1_timer); 309 del_timer_sync(&ndlc->t2_timer); 310 ndlc->t2_active = false; 311 ndlc->t1_active = false; 312 313 skb_queue_purge(&ndlc->rcv_q); 314 skb_queue_purge(&ndlc->send_q); 315 } 316 EXPORT_SYMBOL(ndlc_remove); 317