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
ndlc_open(struct llt_ndlc * ndlc)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
ndlc_close(struct llt_ndlc * ndlc)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
ndlc_send(struct llt_ndlc * ndlc,struct sk_buff * skb)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
llt_ndlc_send_queue(struct llt_ndlc * ndlc)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
llt_ndlc_requeue_data_pending(struct llt_ndlc * ndlc)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
llt_ndlc_rcv_queue(struct llt_ndlc * ndlc)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
llt_ndlc_sm_work(struct work_struct * work)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
ndlc_recv(struct llt_ndlc * ndlc,struct sk_buff * skb)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
ndlc_t1_timeout(struct timer_list * t)238 static void ndlc_t1_timeout(struct timer_list *t)
239 {
240 struct llt_ndlc *ndlc = from_timer(ndlc, t, t1_timer);
241
242 schedule_work(&ndlc->sm_work);
243 }
244
ndlc_t2_timeout(struct timer_list * t)245 static void ndlc_t2_timeout(struct timer_list *t)
246 {
247 struct llt_ndlc *ndlc = from_timer(ndlc, t, t2_timer);
248
249 schedule_work(&ndlc->sm_work);
250 }
251
ndlc_probe(void * phy_id,const struct nfc_phy_ops * phy_ops,struct device * dev,int phy_headroom,int phy_tailroom,struct llt_ndlc ** ndlc_id,struct st_nci_se_status * se_status)252 int ndlc_probe(void *phy_id, const struct nfc_phy_ops *phy_ops,
253 struct device *dev, int phy_headroom, int phy_tailroom,
254 struct llt_ndlc **ndlc_id, struct st_nci_se_status *se_status)
255 {
256 struct llt_ndlc *ndlc;
257
258 ndlc = devm_kzalloc(dev, sizeof(struct llt_ndlc), GFP_KERNEL);
259 if (!ndlc)
260 return -ENOMEM;
261
262 ndlc->ops = phy_ops;
263 ndlc->phy_id = phy_id;
264 ndlc->dev = dev;
265 ndlc->powered = 0;
266
267 *ndlc_id = ndlc;
268
269 /* initialize timers */
270 timer_setup(&ndlc->t1_timer, ndlc_t1_timeout, 0);
271 timer_setup(&ndlc->t2_timer, ndlc_t2_timeout, 0);
272
273 skb_queue_head_init(&ndlc->rcv_q);
274 skb_queue_head_init(&ndlc->send_q);
275 skb_queue_head_init(&ndlc->ack_pending_q);
276
277 INIT_WORK(&ndlc->sm_work, llt_ndlc_sm_work);
278
279 return st_nci_probe(ndlc, phy_headroom, phy_tailroom, se_status);
280 }
281 EXPORT_SYMBOL(ndlc_probe);
282
ndlc_remove(struct llt_ndlc * ndlc)283 void ndlc_remove(struct llt_ndlc *ndlc)
284 {
285 /* cancel timers */
286 del_timer_sync(&ndlc->t1_timer);
287 del_timer_sync(&ndlc->t2_timer);
288 ndlc->t2_active = false;
289 ndlc->t1_active = false;
290 /* cancel work */
291 cancel_work_sync(&ndlc->sm_work);
292
293 st_nci_remove(ndlc->ndev);
294
295 skb_queue_purge(&ndlc->rcv_q);
296 skb_queue_purge(&ndlc->send_q);
297 }
298 EXPORT_SYMBOL(ndlc_remove);
299