2 * The NFC Controller Interface is the communication protocol between an
3 * NFC Controller (NFCC) and a Device Host (DH).
5 * Copyright (C) 2011 Texas Instruments, Inc.
7 * Written by Ilan Elias <ilane@ti.com>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2
11 * as published by the Free Software Foundation
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include <linux/types.h>
25 #include <linux/interrupt.h>
26 #include <linux/wait.h>
27 #include <linux/bitops.h>
28 #include <linux/skbuff.h>
31 #include <net/nfc/nci.h>
32 #include <net/nfc/nci_core.h>
33 #include <linux/nfc.h>
35 /* Complete data exchange transaction and forward skb to nfc core */
36 void nci_data_exchange_complete(struct nci_dev *ndev,
40 data_exchange_cb_t cb = ndev->data_exchange_cb;
41 void *cb_context = ndev->data_exchange_cb_context;
43 nfc_dbg("entry, len %d, err %d", ((skb) ? (skb->len) : (0)), err);
46 ndev->data_exchange_cb = NULL;
47 ndev->data_exchange_cb_context = 0;
49 /* forward skb to nfc core */
50 cb(cb_context, skb, err);
52 nfc_err("no rx callback, dropping rx data...");
54 /* no waiting callback, free skb */
58 clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
61 /* ----------------- NCI TX Data ----------------- */
63 static inline void nci_push_data_hdr(struct nci_dev *ndev,
68 struct nci_data_hdr *hdr;
71 hdr = (struct nci_data_hdr *) skb_push(skb, NCI_DATA_HDR_SIZE);
72 hdr->conn_id = conn_id;
76 nci_mt_set((__u8 *)hdr, NCI_MT_DATA_PKT);
77 nci_pbf_set((__u8 *)hdr, pbf);
79 skb->dev = (void *) ndev;
82 static int nci_queue_tx_data_frags(struct nci_dev *ndev,
84 struct sk_buff *skb) {
85 int total_len = skb->len;
86 unsigned char *data = skb->data;
88 struct sk_buff_head frags_q;
89 struct sk_buff *skb_frag;
93 nfc_dbg("entry, conn_id 0x%x, total_len %d", conn_id, total_len);
95 __skb_queue_head_init(&frags_q);
99 min_t(int, total_len, ndev->max_data_pkt_payload_size);
101 skb_frag = nci_skb_alloc(ndev,
102 (NCI_DATA_HDR_SIZE + frag_len),
104 if (skb_frag == NULL) {
108 skb_reserve(skb_frag, NCI_DATA_HDR_SIZE);
110 /* first, copy the data */
111 memcpy(skb_put(skb_frag, frag_len), data, frag_len);
113 /* second, set the header */
114 nci_push_data_hdr(ndev, conn_id, skb_frag,
115 ((total_len == frag_len) ? (NCI_PBF_LAST) : (NCI_PBF_CONT)));
117 __skb_queue_tail(&frags_q, skb_frag);
120 total_len -= frag_len;
122 nfc_dbg("frag_len %d, remaining total_len %d",
123 frag_len, total_len);
126 /* queue all fragments atomically */
127 spin_lock_irqsave(&ndev->tx_q.lock, flags);
129 while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
130 __skb_queue_tail(&ndev->tx_q, skb_frag);
132 spin_unlock_irqrestore(&ndev->tx_q.lock, flags);
134 /* free the original skb */
140 while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
148 int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb)
152 nfc_dbg("entry, conn_id 0x%x, plen %d", conn_id, skb->len);
154 /* check if the packet need to be fragmented */
155 if (skb->len <= ndev->max_data_pkt_payload_size) {
156 /* no need to fragment packet */
157 nci_push_data_hdr(ndev, conn_id, skb, NCI_PBF_LAST);
159 skb_queue_tail(&ndev->tx_q, skb);
161 /* fragment packet and queue the fragments */
162 rc = nci_queue_tx_data_frags(ndev, conn_id, skb);
164 nfc_err("failed to fragment tx data packet");
169 queue_work(ndev->tx_wq, &ndev->tx_work);
180 /* ----------------- NCI RX Data ----------------- */
182 static void nci_add_rx_data_frag(struct nci_dev *ndev,
189 if (ndev->rx_data_reassembly) {
190 reassembly_len = ndev->rx_data_reassembly->len;
192 /* first, make enough room for the already accumulated data */
193 if (skb_cow_head(skb, reassembly_len)) {
194 nfc_err("error adding room for accumulated rx data");
199 kfree_skb(ndev->rx_data_reassembly);
200 ndev->rx_data_reassembly = 0;
206 /* second, combine the two fragments */
207 memcpy(skb_push(skb, reassembly_len),
208 ndev->rx_data_reassembly->data,
211 /* third, free old reassembly */
212 kfree_skb(ndev->rx_data_reassembly);
213 ndev->rx_data_reassembly = 0;
216 if (pbf == NCI_PBF_CONT) {
217 /* need to wait for next fragment, store skb and exit */
218 ndev->rx_data_reassembly = skb;
223 nci_data_exchange_complete(ndev, skb, err);
227 void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb)
229 __u8 pbf = nci_pbf(skb->data);
231 nfc_dbg("entry, len %d", skb->len);
233 nfc_dbg("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d",
235 nci_conn_id(skb->data),
236 nci_plen(skb->data));
238 /* strip the nci data header */
239 skb_pull(skb, NCI_DATA_HDR_SIZE);
241 if (ndev->target_active_prot == NFC_PROTO_MIFARE) {
242 /* frame I/F => remove the status byte */
243 nfc_dbg("NFC_PROTO_MIFARE => remove the status byte");
244 skb_trim(skb, (skb->len - 1));
247 nci_add_rx_data_frag(ndev, skb, pbf);