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 int nci_conn_max_data_pkt_payload_size(struct nci_dev *ndev, __u8 conn_id) 94 { 95 struct nci_conn_info *conn_info; 96 97 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id); 98 if (!conn_info) 99 return -EPROTO; 100 101 return conn_info->max_pkt_payload_len; 102 } 103 EXPORT_SYMBOL(nci_conn_max_data_pkt_payload_size); 104 105 static int nci_queue_tx_data_frags(struct nci_dev *ndev, 106 __u8 conn_id, 107 struct sk_buff *skb) { 108 struct nci_conn_info *conn_info; 109 int total_len = skb->len; 110 unsigned char *data = skb->data; 111 unsigned long flags; 112 struct sk_buff_head frags_q; 113 struct sk_buff *skb_frag; 114 int frag_len; 115 int rc = 0; 116 117 pr_debug("conn_id 0x%x, total_len %d\n", conn_id, total_len); 118 119 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id); 120 if (!conn_info) { 121 rc = -EPROTO; 122 goto free_exit; 123 } 124 125 __skb_queue_head_init(&frags_q); 126 127 while (total_len) { 128 frag_len = 129 min_t(int, total_len, conn_info->max_pkt_payload_len); 130 131 skb_frag = nci_skb_alloc(ndev, 132 (NCI_DATA_HDR_SIZE + frag_len), 133 GFP_KERNEL); 134 if (skb_frag == NULL) { 135 rc = -ENOMEM; 136 goto free_exit; 137 } 138 skb_reserve(skb_frag, NCI_DATA_HDR_SIZE); 139 140 /* first, copy the data */ 141 memcpy(skb_put(skb_frag, frag_len), data, frag_len); 142 143 /* second, set the header */ 144 nci_push_data_hdr(ndev, conn_id, skb_frag, 145 ((total_len == frag_len) ? 146 (NCI_PBF_LAST) : (NCI_PBF_CONT))); 147 148 __skb_queue_tail(&frags_q, skb_frag); 149 150 data += frag_len; 151 total_len -= frag_len; 152 153 pr_debug("frag_len %d, remaining total_len %d\n", 154 frag_len, total_len); 155 } 156 157 /* queue all fragments atomically */ 158 spin_lock_irqsave(&ndev->tx_q.lock, flags); 159 160 while ((skb_frag = __skb_dequeue(&frags_q)) != NULL) 161 __skb_queue_tail(&ndev->tx_q, skb_frag); 162 163 spin_unlock_irqrestore(&ndev->tx_q.lock, flags); 164 165 /* free the original skb */ 166 kfree_skb(skb); 167 168 goto exit; 169 170 free_exit: 171 while ((skb_frag = __skb_dequeue(&frags_q)) != NULL) 172 kfree_skb(skb_frag); 173 174 exit: 175 return rc; 176 } 177 178 /* Send NCI data */ 179 int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb) 180 { 181 struct nci_conn_info *conn_info; 182 int rc = 0; 183 184 pr_debug("conn_id 0x%x, plen %d\n", conn_id, skb->len); 185 186 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id); 187 if (!conn_info) { 188 rc = -EPROTO; 189 goto free_exit; 190 } 191 192 /* check if the packet need to be fragmented */ 193 if (skb->len <= conn_info->max_pkt_payload_len) { 194 /* no need to fragment packet */ 195 nci_push_data_hdr(ndev, conn_id, skb, NCI_PBF_LAST); 196 197 skb_queue_tail(&ndev->tx_q, skb); 198 } else { 199 /* fragment packet and queue the fragments */ 200 rc = nci_queue_tx_data_frags(ndev, conn_id, skb); 201 if (rc) { 202 pr_err("failed to fragment tx data packet\n"); 203 goto free_exit; 204 } 205 } 206 207 ndev->cur_conn_id = conn_id; 208 queue_work(ndev->tx_wq, &ndev->tx_work); 209 210 goto exit; 211 212 free_exit: 213 kfree_skb(skb); 214 215 exit: 216 return rc; 217 } 218 EXPORT_SYMBOL(nci_send_data); 219 220 /* ----------------- NCI RX Data ----------------- */ 221 222 static void nci_add_rx_data_frag(struct nci_dev *ndev, 223 struct sk_buff *skb, 224 __u8 pbf, __u8 conn_id, __u8 status) 225 { 226 int reassembly_len; 227 int err = 0; 228 229 if (status) { 230 err = status; 231 goto exit; 232 } 233 234 if (ndev->rx_data_reassembly) { 235 reassembly_len = ndev->rx_data_reassembly->len; 236 237 /* first, make enough room for the already accumulated data */ 238 if (skb_cow_head(skb, reassembly_len)) { 239 pr_err("error adding room for accumulated rx data\n"); 240 241 kfree_skb(skb); 242 skb = NULL; 243 244 kfree_skb(ndev->rx_data_reassembly); 245 ndev->rx_data_reassembly = NULL; 246 247 err = -ENOMEM; 248 goto exit; 249 } 250 251 /* second, combine the two fragments */ 252 memcpy(skb_push(skb, reassembly_len), 253 ndev->rx_data_reassembly->data, 254 reassembly_len); 255 256 /* third, free old reassembly */ 257 kfree_skb(ndev->rx_data_reassembly); 258 ndev->rx_data_reassembly = NULL; 259 } 260 261 if (pbf == NCI_PBF_CONT) { 262 /* need to wait for next fragment, store skb and exit */ 263 ndev->rx_data_reassembly = skb; 264 return; 265 } 266 267 exit: 268 if (ndev->nfc_dev->rf_mode == NFC_RF_TARGET) { 269 /* Data received in Target mode, forward to nfc core */ 270 err = nfc_tm_data_received(ndev->nfc_dev, skb); 271 if (err) 272 pr_err("unable to handle received data\n"); 273 } else { 274 nci_data_exchange_complete(ndev, skb, conn_id, err); 275 } 276 } 277 278 /* Rx Data packet */ 279 void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb) 280 { 281 __u8 pbf = nci_pbf(skb->data); 282 __u8 status = 0; 283 __u8 conn_id = nci_conn_id(skb->data); 284 struct nci_conn_info *conn_info; 285 286 pr_debug("len %d\n", skb->len); 287 288 pr_debug("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d\n", 289 nci_pbf(skb->data), 290 nci_conn_id(skb->data), 291 nci_plen(skb->data)); 292 293 conn_info = nci_get_conn_info_by_conn_id(ndev, nci_conn_id(skb->data)); 294 if (!conn_info) 295 return; 296 297 /* strip the nci data header */ 298 skb_pull(skb, NCI_DATA_HDR_SIZE); 299 300 if (ndev->target_active_prot == NFC_PROTO_MIFARE || 301 ndev->target_active_prot == NFC_PROTO_JEWEL || 302 ndev->target_active_prot == NFC_PROTO_FELICA || 303 ndev->target_active_prot == NFC_PROTO_ISO15693) { 304 /* frame I/F => remove the status byte */ 305 pr_debug("frame I/F => remove the status byte\n"); 306 status = skb->data[skb->len - 1]; 307 skb_trim(skb, (skb->len - 1)); 308 } 309 310 nci_add_rx_data_frag(ndev, skb, pbf, conn_id, nci_to_errno(status)); 311 } 312