aboutsummaryrefslogtreecommitdiffstats
path: root/net/nfc/nci/data.c
blob: b002e18f38c81f55dfbccf0585e75ff909c6b66b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  The NFC Controller Interface is the communication protocol between an
 *  NFC Controller (NFCC) and a Device Host (DH).
 *
 *  Copyright (C) 2011 Texas Instruments, Inc.
 *  Copyright (C) 2014 Marvell International Ltd.
 *
 *  Written by Ilan Elias <ilane@ti.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__

#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/bitops.h>
#include <linux/skbuff.h>

#include "../nfc.h"
#include <net/nfc/nci.h>
#include <net/nfc/nci_core.h>
#include <linux/nfc.h>

/* Complete data exchange transaction and forward skb to nfc core */
void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb,
				__u8 conn_id, int err)
{
	struct nci_conn_info    *conn_info;
	data_exchange_cb_t cb;
	void *cb_context;

	conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
	if (!conn_info) {
		kfree_skb(skb);
		goto exit;
	}

	cb = conn_info->data_exchange_cb;
	cb_context = conn_info->data_exchange_cb_context;

	pr_debug("len %d, err %d\n", skb ? skb->len : 0, err);

	/* data exchange is complete, stop the data timer */
	del_timer_sync(&ndev->data_timer);
	clear_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags);

	if (cb) {
		/* forward skb to nfc core */
		cb(cb_context, skb, err);
	} else if (skb) {
		pr_err("no rx callback, dropping rx data...\n");

		/* no waiting callback, free skb */
		kfree_skb(skb);
	}

exit:
	clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
}

/* ----------------- NCI TX Data ----------------- */

static inline void nci_push_data_hdr(struct nci_dev *ndev,
				     __u8 conn_id,
				     struct sk_buff *skb,
				     __u8 pbf)
{
	struct nci_data_hdr *hdr;
	int plen = skb->len;

	hdr = skb_push(skb, NCI_DATA_HDR_SIZE);
	hdr->conn_id = conn_id;
	hdr->rfu = 0;
	hdr->plen = plen;

	nci_mt_set((__u8 *)hdr, NCI_MT_DATA_PKT);
	nci_pbf_set((__u8 *)hdr, pbf);
}

int nci_conn_max_data_pkt_payload_size(struct nci_dev *ndev, __u8 conn_id)
{
	struct nci_conn_info *conn_info;

	conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
	if (!conn_info)
		return -EPROTO;

	return conn_info->max_pkt_payload_len;
}
EXPORT_SYMBOL(nci_conn_max_data_pkt_payload_size);

static int nci_queue_tx_data_frags(struct nci_dev *ndev,
				   __u8 conn_id,
				   struct sk_buff *skb) {
	struct nci_conn_info    *conn_info;
	int total_len = skb->len;
	unsigned char *data = skb->data;
	unsigned long flags;
	struct sk_buff_head frags_q;
	struct sk_buff *skb_frag;
	int frag_len;
	int rc = 0;

	pr_debug("conn_id 0x%x, total_len %d\n", conn_id, total_len);

	conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
	if (!conn_info) {
		rc = -EPROTO;
		goto exit;
	}

	__skb_queue_head_init(&frags_q);

	while (total_len) {
		frag_len =
			min_t(int, total_len, conn_info->max_pkt_payload_len);

		skb_frag = nci_skb_alloc(ndev,
					 (NCI_DATA_HDR_SIZE + frag_len),
					 GFP_ATOMIC);
		if (skb_frag == NULL) {
			rc = -ENOMEM;
			goto free_exit;
		}
		skb_reserve(skb_frag, NCI_DATA_HDR_SIZE);

		/* first, copy the data */
		skb_put_data(skb_frag, data, frag_len);

		/* second, set the header */
		nci_push_data_hdr(ndev, conn_id, skb_frag,
				  ((total_len == frag_len) ?
				   (NCI_PBF_LAST) : (NCI_PBF_CONT)));

		__skb_queue_tail(&frags_q, skb_frag);

		data += frag_len;
		total_len -= frag_len;

		pr_debug("frag_len %d, remaining total_len %d\n",
			 frag_len, total_len);
	}

	/* queue all fragments atomically */
	spin_lock_irqsave(&ndev->tx_q.lock, flags);

	while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
		__skb_queue_tail(&ndev->tx_q, skb_frag);

	spin_unlock_irqrestore(&ndev->tx_q.lock, flags);

	/* free the original skb */
	kfree_skb(skb);

	goto exit;

free_exit:
	while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
		kfree_skb(skb_frag);

exit:
	return rc;
}

/* Send NCI data */
int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb)
{
	struct nci_conn_info    *conn_info;
	int rc = 0;

	pr_debug("conn_id 0x%x, plen %d\n", conn_id, skb->len);

	conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
	if (!conn_info) {
		rc = -EPROTO;
		goto free_exit;
	}

	/* check if the packet need to be fragmented */
	if (skb->len <= conn_info->max_pkt_payload_len) {
		/* no need to fragment packet */
		nci_push_data_hdr(ndev, conn_id, skb, NCI_PBF_LAST);

		skb_queue_tail(&ndev->tx_q, skb);
	} else {
		/* fragment packet and queue the fragments */
		rc = nci_queue_tx_data_frags(ndev, conn_id, skb);
		if (rc) {
			pr_err("failed to fragment tx data packet\n");
			goto free_exit;
		}
	}

	ndev->cur_conn_id = conn_id;
	queue_work(ndev->tx_wq, &ndev->tx_work);

	goto exit;

free_exit:
	kfree_skb(skb);

exit:
	return rc;
}
EXPORT_SYMBOL(nci_send_data);

/* ----------------- NCI RX Data ----------------- */

static void nci_add_rx_data_frag(struct nci_dev *ndev,
				 struct sk_buff *skb,
				 __u8 pbf, __u8 conn_id, __u8 status)
{
	int reassembly_len;
	int err = 0;

	if (status) {
		err = status;
		goto exit;
	}

	if (ndev->rx_data_reassembly) {
		reassembly_len = ndev->rx_data_reassembly->len;

		/* first, make enough room for the already accumulated data */
		if (skb_cow_head(skb, reassembly_len)) {
			pr_err("error adding room for accumulated rx data\n");

			kfree_skb(skb);
			skb = NULL;

			kfree_skb(ndev->rx_data_reassembly);
			ndev->rx_data_reassembly = NULL;

			err = -ENOMEM;
			goto exit;
		}

		/* second, combine the two fragments */
		memcpy(skb_push(skb, reassembly_len),
		       ndev->rx_data_reassembly->data,
		       reassembly_len);

		/* third, free old reassembly */
		kfree_skb(ndev->rx_data_reassembly);
		ndev->rx_data_reassembly = NULL;
	}

	if (pbf == NCI_PBF_CONT) {
		/* need to wait for next fragment, store skb and exit */
		ndev->rx_data_reassembly = skb;
		return;
	}

exit:
	if (ndev->nfc_dev->rf_mode == NFC_RF_TARGET) {
		/* Data received in Target mode, forward to nfc core */
		err = nfc_tm_data_received(ndev->nfc_dev, skb);
		if (err)
			pr_err("unable to handle received data\n");
	} else {
		nci_data_exchange_complete(ndev, skb, conn_id, err);
	}
}

/* Rx Data packet */
void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb)
{
	__u8 pbf = nci_pbf(skb->data);
	__u8 status = 0;
	__u8 conn_id = nci_conn_id(skb->data);
	struct nci_conn_info    *conn_info;

	pr_debug("len %d\n", skb->len);

	pr_debug("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d\n",
		 nci_pbf(skb->data),
		 nci_conn_id(skb->data),
		 nci_plen(skb->data));

	conn_info = nci_get_conn_info_by_conn_id(ndev, nci_conn_id(skb->data));
	if (!conn_info)
		return;

	/* strip the nci data header */
	skb_pull(skb, NCI_DATA_HDR_SIZE);

	if (ndev->target_active_prot == NFC_PROTO_MIFARE ||
	    ndev->target_active_prot == NFC_PROTO_JEWEL ||
	    ndev->target_active_prot == NFC_PROTO_FELICA ||
	    ndev->target_active_prot == NFC_PROTO_ISO15693) {
		/* frame I/F => remove the status byte */
		pr_debug("frame I/F => remove the status byte\n");
		status = skb->data[skb->len - 1];
		skb_trim(skb, (skb->len - 1));
	}

	nci_add_rx_data_frag(ndev, skb, pbf, conn_id, nci_to_errno(status));
}