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(timer: &ndev->data_timer); |
46 | clear_bit(nr: NCI_DATA_EXCHANGE_TO, addr: &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(nr: NCI_DATA_EXCHANGE, addr: &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(list: &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 | len: (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: skb_frag, NCI_DATA_HDR_SIZE); |
127 | |
128 | /* first, copy the data */ |
129 | skb_put_data(skb: skb_frag, data, len: frag_len); |
130 | |
131 | /* second, set the header */ |
132 | nci_push_data_hdr(ndev, conn_id, skb: skb_frag, |
133 | pbf: ((total_len == frag_len) ? |
134 | (NCI_PBF_LAST) : (NCI_PBF_CONT))); |
135 | |
136 | __skb_queue_tail(list: &frags_q, newsk: 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(list: &frags_q)) != NULL) |
149 | __skb_queue_tail(list: &ndev->tx_q, newsk: skb_frag); |
150 | |
151 | spin_unlock_irqrestore(lock: &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(list: &frags_q)) != NULL) |
160 | kfree_skb(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(list: &ndev->tx_q, newsk: 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(wq: ndev->tx_wq, work: &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, headroom: 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(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(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(dev: 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, len: (skb->len - 1)); |
298 | } |
299 | |
300 | nci_add_rx_data_frag(ndev, skb, pbf, conn_id, status: nci_to_errno(code: status)); |
301 | } |
302 | |