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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 <[email protected]>
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 */
26void 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 clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
37 return;
38 }
39
40 cb = conn_info->data_exchange_cb;
41 cb_context = conn_info->data_exchange_cb_context;
42
43 pr_debug("len %d, err %d\n", skb ? skb->len : 0, err);
44
45 /* data exchange is complete, stop the data timer */
46 timer_delete_sync(&ndev->data_timer);
47 clear_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags);
48
49 /* Claim completion atomically -- both close and rx_work may race here */
50 if (!test_and_clear_bit(NCI_DATA_EXCHANGE, &ndev->flags)) {
51 kfree_skb(skb);
52 return;
53 }
54
55 if (cb) {
56 /* forward skb to nfc core */
57 cb(cb_context, skb, err);
58 } else if (skb) {
59 pr_err("no rx callback, dropping rx data...\n");
60
61 /* no waiting callback, free skb */
62 kfree_skb(skb);
63 }
64}
65
66/* ----------------- NCI TX Data ----------------- */
67
68static inline void nci_push_data_hdr(struct nci_dev *ndev,
69 __u8 conn_id,
70 struct sk_buff *skb,
71 __u8 pbf)
72{
73 struct nci_data_hdr *hdr;
74 int plen = skb->len;
75
76 hdr = skb_push(skb, NCI_DATA_HDR_SIZE);
77 hdr->conn_id = conn_id;
78 hdr->rfu = 0;
79 hdr->plen = plen;
80
81 nci_mt_set((__u8 *)hdr, NCI_MT_DATA_PKT);
82 nci_pbf_set((__u8 *)hdr, pbf);
83}
84
85int nci_conn_max_data_pkt_payload_size(struct nci_dev *ndev, __u8 conn_id)
86{
87 const struct nci_conn_info *conn_info;
88
89 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
90 if (!conn_info)
91 return -EPROTO;
92
93 return conn_info->max_pkt_payload_len;
94}
95EXPORT_SYMBOL(nci_conn_max_data_pkt_payload_size);
96
97static int nci_queue_tx_data_frags(struct nci_dev *ndev,
98 __u8 conn_id,
99 struct sk_buff *skb) {
100 const struct nci_conn_info *conn_info;
101 int total_len = skb->len;
102 const unsigned char *data = skb->data;
103 unsigned long flags;
104 struct sk_buff_head frags_q;
105 struct sk_buff *skb_frag;
106 int frag_len;
107 int rc = 0;
108
109 pr_debug("conn_id 0x%x, total_len %d\n", conn_id, total_len);
110
111 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
112 if (!conn_info) {
113 rc = -EPROTO;
114 goto exit;
115 }
116
117 __skb_queue_head_init(&frags_q);
118
119 while (total_len) {
120 frag_len =
121 min_t(int, total_len, conn_info->max_pkt_payload_len);
122
123 skb_frag = nci_skb_alloc(ndev,
124 (NCI_DATA_HDR_SIZE + frag_len),
125 GFP_ATOMIC);
126 if (skb_frag == NULL) {
127 rc = -ENOMEM;
128 goto free_exit;
129 }
130 skb_reserve(skb_frag, NCI_DATA_HDR_SIZE);
131
132 /* first, copy the data */
133 skb_put_data(skb_frag, data, frag_len);
134
135 /* second, set the header */
136 nci_push_data_hdr(ndev, conn_id, skb_frag,
137 ((total_len == frag_len) ?
138 (NCI_PBF_LAST) : (NCI_PBF_CONT)));
139
140 __skb_queue_tail(&frags_q, skb_frag);
141
142 data += frag_len;
143 total_len -= frag_len;
144
145 pr_debug("frag_len %d, remaining total_len %d\n",
146 frag_len, total_len);
147 }
148
149 /* queue all fragments atomically */
150 spin_lock_irqsave(&ndev->tx_q.lock, flags);
151
152 while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
153 __skb_queue_tail(&ndev->tx_q, skb_frag);
154
155 spin_unlock_irqrestore(&ndev->tx_q.lock, flags);
156
157 /* free the original skb */
158 kfree_skb(skb);
159
160 goto exit;
161
162free_exit:
163 while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
164 kfree_skb(skb_frag);
165
166exit:
167 return rc;
168}
169
170/* Send NCI data */
171int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb)
172{
173 const struct nci_conn_info *conn_info;
174 int rc = 0;
175
176 pr_debug("conn_id 0x%x, plen %d\n", conn_id, skb->len);
177
178 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
179 if (!conn_info) {
180 rc = -EPROTO;
181 goto free_exit;
182 }
183
184 /* check if the packet need to be fragmented */
185 if (skb->len <= conn_info->max_pkt_payload_len) {
186 /* no need to fragment packet */
187 nci_push_data_hdr(ndev, conn_id, skb, NCI_PBF_LAST);
188
189 skb_queue_tail(&ndev->tx_q, skb);
190 } else {
191 /* fragment packet and queue the fragments */
192 rc = nci_queue_tx_data_frags(ndev, conn_id, skb);
193 if (rc) {
194 pr_err("failed to fragment tx data packet\n");
195 goto free_exit;
196 }
197 }
198
199 ndev->cur_conn_id = conn_id;
200 queue_work(ndev->tx_wq, &ndev->tx_work);
201
202 goto exit;
203
204free_exit:
205 kfree_skb(skb);
206
207exit:
208 return rc;
209}
210EXPORT_SYMBOL(nci_send_data);
211
212/* ----------------- NCI RX Data ----------------- */
213
214static void nci_add_rx_data_frag(struct nci_dev *ndev,
215 struct sk_buff *skb,
216 __u8 pbf, __u8 conn_id, __u8 status)
217{
218 int reassembly_len;
219 int err = 0;
220
221 if (status) {
222 err = status;
223 goto exit;
224 }
225
226 if (ndev->rx_data_reassembly) {
227 reassembly_len = ndev->rx_data_reassembly->len;
228
229 /* first, make enough room for the already accumulated data */
230 if (skb_cow_head(skb, reassembly_len)) {
231 pr_err("error adding room for accumulated rx data\n");
232
233 kfree_skb(skb);
234 skb = NULL;
235
236 kfree_skb(ndev->rx_data_reassembly);
237 ndev->rx_data_reassembly = NULL;
238
239 err = -ENOMEM;
240 goto exit;
241 }
242
243 /* second, combine the two fragments */
244 memcpy(skb_push(skb, reassembly_len),
245 ndev->rx_data_reassembly->data,
246 reassembly_len);
247
248 /* third, free old reassembly */
249 kfree_skb(ndev->rx_data_reassembly);
250 ndev->rx_data_reassembly = NULL;
251 }
252
253 if (pbf == NCI_PBF_CONT) {
254 /* need to wait for next fragment, store skb and exit */
255 ndev->rx_data_reassembly = skb;
256 return;
257 }
258
259exit:
260 if (ndev->nfc_dev->rf_mode == NFC_RF_TARGET) {
261 /* Data received in Target mode, forward to nfc core */
262 err = nfc_tm_data_received(ndev->nfc_dev, skb);
263 if (err)
264 pr_err("unable to handle received data\n");
265 } else {
266 nci_data_exchange_complete(ndev, skb, conn_id, err);
267 }
268}
269
270/* Rx Data packet */
271void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb)
272{
273 __u8 pbf = nci_pbf(skb->data);
274 __u8 status = 0;
275 __u8 conn_id = nci_conn_id(skb->data);
276 const struct nci_conn_info *conn_info;
277
278 pr_debug("len %d\n", skb->len);
279
280 pr_debug("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d\n",
281 nci_pbf(skb->data),
282 nci_conn_id(skb->data),
283 nci_plen(skb->data));
284
285 conn_info = nci_get_conn_info_by_conn_id(ndev, nci_conn_id(skb->data));
286 if (!conn_info) {
287 kfree_skb(skb);
288 return;
289 }
290
291 /* strip the nci data header */
292 skb_pull(skb, NCI_DATA_HDR_SIZE);
293
294 if (ndev->target_active_prot == NFC_PROTO_MIFARE ||
295 ndev->target_active_prot == NFC_PROTO_JEWEL ||
296 ndev->target_active_prot == NFC_PROTO_FELICA ||
297 ndev->target_active_prot == NFC_PROTO_ISO15693) {
298 /* frame I/F => remove the status byte */
299 pr_debug("frame I/F => remove the status byte\n");
300 status = skb->data[skb->len - 1];
301 skb_trim(skb, (skb->len - 1));
302 }
303
304 nci_add_rx_data_frag(ndev, skb, pbf, conn_id, nci_to_errno(status));
305}