1 /* 2 * The NFC Controller Interface is the communication protocol between an 3 * NFC Controller (NFCC) and a Device Host (DH). 4 * 5 * Copyright (C) 2011 Texas Instruments, Inc. 6 * Copyright (C) 2014 Marvell International Ltd. 7 * 8 * Written by Ilan Elias <ilane@ti.com> 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 12 * as published by the Free Software Foundation 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, see <http://www.gnu.org/licenses/>. 21 * 22 */ 23 24 #define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__ 25 26 #include <linux/types.h> 27 #include <linux/interrupt.h> 28 #include <linux/wait.h> 29 #include <linux/bitops.h> 30 #include <linux/skbuff.h> 31 32 #include "../nfc.h" 33 #include <net/nfc/nci.h> 34 #include <net/nfc/nci_core.h> 35 #include <linux/nfc.h> 36 37 /* Complete data exchange transaction and forward skb to nfc core */ 38 void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb, 39 __u8 conn_id, int err) 40 { 41 struct nci_conn_info *conn_info; 42 data_exchange_cb_t cb; 43 void *cb_context; 44 45 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id); 46 if (!conn_info) { 47 kfree_skb(skb); 48 goto exit; 49 } 50 51 cb = conn_info->data_exchange_cb; 52 cb_context = conn_info->data_exchange_cb_context; 53 54 pr_debug("len %d, err %d\n", skb ? skb->len : 0, err); 55 56 /* data exchange is complete, stop the data timer */ 57 del_timer_sync(&ndev->data_timer); 58 clear_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags); 59 60 if (cb) { 61 /* forward skb to nfc core */ 62 cb(cb_context, skb, err); 63 } else if (skb) { 64 pr_err("no rx callback, dropping rx data...\n"); 65 66 /* no waiting callback, free skb */ 67 kfree_skb(skb); 68 } 69 70 exit: 71 clear_bit(NCI_DATA_EXCHANGE, &ndev->flags); 72 } 73 74 /* ----------------- NCI TX Data ----------------- */ 75 76 static inline void nci_push_data_hdr(struct nci_dev *ndev, 77 __u8 conn_id, 78 struct sk_buff *skb, 79 __u8 pbf) 80 { 81 struct nci_data_hdr *hdr; 82 int plen = skb->len; 83 84 hdr = (struct nci_data_hdr *) skb_push(skb, NCI_DATA_HDR_SIZE); 85 hdr->conn_id = conn_id; 86 hdr->rfu = 0; 87 hdr->plen = plen; 88 89 nci_mt_set((__u8 *)hdr, NCI_MT_DATA_PKT); 90 nci_pbf_set((__u8 *)hdr, pbf); 91 } 92 93 static int nci_queue_tx_data_frags(struct nci_dev *ndev, 94 __u8 conn_id, 95 struct sk_buff *skb) { 96 struct nci_conn_info *conn_info; 97 int total_len = skb->len; 98 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 free_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_KERNEL); 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 memcpy(skb_put(skb_frag, frag_len), 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; 157 158 free_exit: 159 while ((skb_frag = __skb_dequeue(&frags_q)) != NULL) 160 kfree_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 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; 199 200 free_exit: 201 kfree_skb(skb); 202 203 exit: 204 return rc; 205 } 206 207 /* ----------------- NCI RX Data ----------------- */ 208 209 static void nci_add_rx_data_frag(struct nci_dev *ndev, 210 struct sk_buff *skb, 211 __u8 pbf, __u8 conn_id, __u8 status) 212 { 213 int reassembly_len; 214 int err = 0; 215 216 if (status) { 217 err = status; 218 goto exit; 219 } 220 221 if (ndev->rx_data_reassembly) { 222 reassembly_len = ndev->rx_data_reassembly->len; 223 224 /* first, make enough room for the already accumulated data */ 225 if (skb_cow_head(skb, reassembly_len)) { 226 pr_err("error adding room for accumulated rx data\n"); 227 228 kfree_skb(skb); 229 skb = NULL; 230 231 kfree_skb(ndev->rx_data_reassembly); 232 ndev->rx_data_reassembly = NULL; 233 234 err = -ENOMEM; 235 goto exit; 236 } 237 238 /* second, combine the two fragments */ 239 memcpy(skb_push(skb, reassembly_len), 240 ndev->rx_data_reassembly->data, 241 reassembly_len); 242 243 /* third, free old reassembly */ 244 kfree_skb(ndev->rx_data_reassembly); 245 ndev->rx_data_reassembly = NULL; 246 } 247 248 if (pbf == NCI_PBF_CONT) { 249 /* need to wait for next fragment, store skb and exit */ 250 ndev->rx_data_reassembly = skb; 251 return; 252 } 253 254 exit: 255 if (ndev->nfc_dev->rf_mode == NFC_RF_TARGET) { 256 /* Data received in Target mode, forward to nfc core */ 257 err = nfc_tm_data_received(ndev->nfc_dev, skb); 258 if (err) 259 pr_err("unable to handle received data\n"); 260 } else { 261 nci_data_exchange_complete(ndev, skb, conn_id, err); 262 } 263 } 264 265 /* Rx Data packet */ 266 void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb) 267 { 268 __u8 pbf = nci_pbf(skb->data); 269 __u8 status = 0; 270 __u8 conn_id = nci_conn_id(skb->data); 271 struct nci_conn_info *conn_info; 272 273 pr_debug("len %d\n", skb->len); 274 275 pr_debug("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d\n", 276 nci_pbf(skb->data), 277 nci_conn_id(skb->data), 278 nci_plen(skb->data)); 279 280 conn_info = nci_get_conn_info_by_conn_id(ndev, nci_conn_id(skb->data)); 281 if (!conn_info) 282 return; 283 284 /* strip the nci data header */ 285 skb_pull(skb, NCI_DATA_HDR_SIZE); 286 287 if (ndev->target_active_prot == NFC_PROTO_MIFARE || 288 ndev->target_active_prot == NFC_PROTO_JEWEL || 289 ndev->target_active_prot == NFC_PROTO_FELICA || 290 ndev->target_active_prot == NFC_PROTO_ISO15693) { 291 /* frame I/F => remove the status byte */ 292 pr_debug("frame I/F => remove the status byte\n"); 293 status = skb->data[skb->len - 1]; 294 skb_trim(skb, (skb->len - 1)); 295 } 296 297 nci_add_rx_data_frag(ndev, skb, pbf, conn_id, nci_to_errno(status)); 298 } 299