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 */
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		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
58exit:
59	clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
60}
61
62/* ----------------- NCI TX Data ----------------- */
63
64static 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
81int 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}
91EXPORT_SYMBOL(nci_conn_max_data_pkt_payload_size);
92
93static 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
158free_exit:
159	while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
160		kfree_skb(skb_frag);
161
162exit:
163	return rc;
164}
165
166/* Send NCI data */
167int 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
200free_exit:
201	kfree_skb(skb);
202
203exit:
204	return rc;
205}
206EXPORT_SYMBOL(nci_send_data);
207
208/* ----------------- NCI RX Data ----------------- */
209
210static 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
255exit:
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 */
267void 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