1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * The NFC Controller Interface is the communication protocol between an
4 * NFC Controller (NFCC) and a Device Host (DH).
5 *
6 * Copyright (C) 2011 Texas Instruments, Inc.
7 * Copyright (C) 2014 Marvell International Ltd.
8 *
9 * Written by Ilan Elias <ilane@ti.com>
10 */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__
13
14 #include <linux/types.h>
15 #include <linux/interrupt.h>
16 #include <linux/wait.h>
17 #include <linux/bitops.h>
18 #include <linux/skbuff.h>
19
20 #include "../nfc.h"
21 #include <net/nfc/nci.h>
22 #include <net/nfc/nci_core.h>
23 #include <linux/nfc.h>
24
25 /* Complete data exchange transaction and forward skb to nfc core */
26 void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb,
27 __u8 conn_id, int err)
28 {
29 const struct nci_conn_info *conn_info;
30 data_exchange_cb_t cb;
31 void *cb_context;
32
33 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
34 if (!conn_info) {
35 kfree_skb(skb);
36 goto exit;
37 }
38
39 cb = conn_info->data_exchange_cb;
40 cb_context = conn_info->data_exchange_cb_context;
41
42 pr_debug("len %d, err %d\n", skb ? skb->len : 0, err);
43
44 /* data exchange is complete, stop the data timer */
45 del_timer_sync(&ndev->data_timer);
46 clear_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags);
47
48 if (cb) {
49 /* forward skb to nfc core */
50 cb(cb_context, skb, err);
51 } else if (skb) {
52 pr_err("no rx callback, dropping rx data...\n");
53
54 /* no waiting callback, free skb */
55 kfree_skb(skb);
56 }
57
58 exit:
59 clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
60 }
61
62 /* ----------------- NCI TX Data ----------------- */
63
64 static inline void nci_push_data_hdr(struct nci_dev *ndev,
65 __u8 conn_id,
66 struct sk_buff *skb,
67 __u8 pbf)
68 {
69 struct nci_data_hdr *hdr;
70 int plen = skb->len;
71
72 hdr = skb_push(skb, NCI_DATA_HDR_SIZE);
73 hdr->conn_id = conn_id;
74 hdr->rfu = 0;
75 hdr->plen = plen;
76
77 nci_mt_set((__u8 *)hdr, NCI_MT_DATA_PKT);
78 nci_pbf_set((__u8 *)hdr, pbf);
79 }
80
81 int nci_conn_max_data_pkt_payload_size(struct nci_dev *ndev, __u8 conn_id)
82 {
83 const struct nci_conn_info *conn_info;
84
85 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
86 if (!conn_info)
87 return -EPROTO;
88
89 return conn_info->max_pkt_payload_len;
90 }
91 EXPORT_SYMBOL(nci_conn_max_data_pkt_payload_size);
92
93 static int nci_queue_tx_data_frags(struct nci_dev *ndev,
94 __u8 conn_id,
95 struct sk_buff *skb) {
96 const struct nci_conn_info *conn_info;
97 int total_len = skb->len;
98 const unsigned char *data = skb->data;
99 unsigned long flags;
100 struct sk_buff_head frags_q;
101 struct sk_buff *skb_frag;
102 int frag_len;
103 int rc = 0;
104
105 pr_debug("conn_id 0x%x, total_len %d\n", conn_id, total_len);
106
107 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
108 if (!conn_info) {
109 rc = -EPROTO;
110 goto exit;
111 }
112
113 __skb_queue_head_init(&frags_q);
114
115 while (total_len) {
116 frag_len =
117 min_t(int, total_len, conn_info->max_pkt_payload_len);
118
119 skb_frag = nci_skb_alloc(ndev,
120 (NCI_DATA_HDR_SIZE + frag_len),
121 GFP_ATOMIC);
122 if (skb_frag == NULL) {
123 rc = -ENOMEM;
124 goto free_exit;
125 }
126 skb_reserve(skb_frag, NCI_DATA_HDR_SIZE);
127
128 /* first, copy the data */
129 skb_put_data(skb_frag, data, frag_len);
130
131 /* second, set the header */
132 nci_push_data_hdr(ndev, conn_id, skb_frag,
133 ((total_len == frag_len) ?
134 (NCI_PBF_LAST) : (NCI_PBF_CONT)));
135
136 __skb_queue_tail(&frags_q, skb_frag);
137
138 data += frag_len;
139 total_len -= frag_len;
140
141 pr_debug("frag_len %d, remaining total_len %d\n",
142 frag_len, total_len);
143 }
144
145 /* queue all fragments atomically */
146 spin_lock_irqsave(&ndev->tx_q.lock, flags);
147
148 while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
149 __skb_queue_tail(&ndev->tx_q, skb_frag);
150
151 spin_unlock_irqrestore(&ndev->tx_q.lock, flags);
152
153 /* free the original skb */
154 kfree_skb(skb);
155
156 goto exit;
157
158 free_exit:
159 while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
160 kfree_skb(skb_frag);
161
162 exit:
163 return rc;
164 }
165
166 /* Send NCI data */
167 int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb)
168 {
169 const struct nci_conn_info *conn_info;
170 int rc = 0;
171
172 pr_debug("conn_id 0x%x, plen %d\n", conn_id, skb->len);
173
174 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
175 if (!conn_info) {
176 rc = -EPROTO;
177 goto free_exit;
178 }
179
180 /* check if the packet need to be fragmented */
181 if (skb->len <= conn_info->max_pkt_payload_len) {
182 /* no need to fragment packet */
183 nci_push_data_hdr(ndev, conn_id, skb, NCI_PBF_LAST);
184
185 skb_queue_tail(&ndev->tx_q, skb);
186 } else {
187 /* fragment packet and queue the fragments */
188 rc = nci_queue_tx_data_frags(ndev, conn_id, skb);
189 if (rc) {
190 pr_err("failed to fragment tx data packet\n");
191 goto free_exit;
192 }
193 }
194
195 ndev->cur_conn_id = conn_id;
196 queue_work(ndev->tx_wq, &ndev->tx_work);
197
198 goto exit;
199
200 free_exit:
201 kfree_skb(skb);
202
203 exit:
204 return rc;
205 }
206 EXPORT_SYMBOL(nci_send_data);
207
208 /* ----------------- NCI RX Data ----------------- */
209
210 static void nci_add_rx_data_frag(struct nci_dev *ndev,
211 struct sk_buff *skb,
212 __u8 pbf, __u8 conn_id, __u8 status)
213 {
214 int reassembly_len;
215 int err = 0;
216
217 if (status) {
218 err = status;
219 goto exit;
220 }
221
222 if (ndev->rx_data_reassembly) {
223 reassembly_len = ndev->rx_data_reassembly->len;
224
225 /* first, make enough room for the already accumulated data */
226 if (skb_cow_head(skb, reassembly_len)) {
227 pr_err("error adding room for accumulated rx data\n");
228
229 kfree_skb(skb);
230 skb = NULL;
231
232 kfree_skb(ndev->rx_data_reassembly);
233 ndev->rx_data_reassembly = NULL;
234
235 err = -ENOMEM;
236 goto exit;
237 }
238
239 /* second, combine the two fragments */
240 memcpy(skb_push(skb, reassembly_len),
241 ndev->rx_data_reassembly->data,
242 reassembly_len);
243
244 /* third, free old reassembly */
245 kfree_skb(ndev->rx_data_reassembly);
246 ndev->rx_data_reassembly = NULL;
247 }
248
249 if (pbf == NCI_PBF_CONT) {
250 /* need to wait for next fragment, store skb and exit */
251 ndev->rx_data_reassembly = skb;
252 return;
253 }
254
255 exit:
256 if (ndev->nfc_dev->rf_mode == NFC_RF_TARGET) {
257 /* Data received in Target mode, forward to nfc core */
258 err = nfc_tm_data_received(ndev->nfc_dev, skb);
259 if (err)
260 pr_err("unable to handle received data\n");
261 } else {
262 nci_data_exchange_complete(ndev, skb, conn_id, err);
263 }
264 }
265
266 /* Rx Data packet */
267 void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb)
268 {
269 __u8 pbf = nci_pbf(skb->data);
270 __u8 status = 0;
271 __u8 conn_id = nci_conn_id(skb->data);
272 const struct nci_conn_info *conn_info;
273
274 pr_debug("len %d\n", skb->len);
275
276 pr_debug("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d\n",
277 nci_pbf(skb->data),
278 nci_conn_id(skb->data),
279 nci_plen(skb->data));
280
281 conn_info = nci_get_conn_info_by_conn_id(ndev, nci_conn_id(skb->data));
282 if (!conn_info) {
283 kfree_skb(skb);
284 return;
285 }
286
287 /* strip the nci data header */
288 skb_pull(skb, NCI_DATA_HDR_SIZE);
289
290 if (ndev->target_active_prot == NFC_PROTO_MIFARE ||
291 ndev->target_active_prot == NFC_PROTO_JEWEL ||
292 ndev->target_active_prot == NFC_PROTO_FELICA ||
293 ndev->target_active_prot == NFC_PROTO_ISO15693) {
294 /* frame I/F => remove the status byte */
295 pr_debug("frame I/F => remove the status byte\n");
296 status = skb->data[skb->len - 1];
297 skb_trim(skb, (skb->len - 1));
298 }
299
300 nci_add_rx_data_frag(ndev, skb, pbf, conn_id, nci_to_errno(status));
301 }
302
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