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 */ 26 void 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 clear_bit(NCI_DATA_EXCHANGE, &ndev->flags); 37 return; 38 } 39 40 cb = conn_info->data_exchange_cb; 41 cb_context = conn_info->data_exchange_cb_context; 42 43 pr_debug("len %d, err %d\n", skb ? skb->len : 0, err); 44 45 /* data exchange is complete, stop the data timer */ 46 timer_delete_sync(&ndev->data_timer); 47 clear_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags); 48 49 /* Mark the exchange as done before calling the callback. 50 * The callback (e.g. rawsock_data_exchange_complete) may 51 * want to immediately queue another data exchange. 52 */ 53 clear_bit(NCI_DATA_EXCHANGE, &ndev->flags); 54 55 if (cb) { 56 /* forward skb to nfc core */ 57 cb(cb_context, skb, err); 58 } else if (skb) { 59 pr_err("no rx callback, dropping rx data...\n"); 60 61 /* no waiting callback, free skb */ 62 kfree_skb(skb); 63 } 64 } 65 66 /* ----------------- NCI TX Data ----------------- */ 67 68 static inline void nci_push_data_hdr(struct nci_dev *ndev, 69 __u8 conn_id, 70 struct sk_buff *skb, 71 __u8 pbf) 72 { 73 struct nci_data_hdr *hdr; 74 int plen = skb->len; 75 76 hdr = skb_push(skb, NCI_DATA_HDR_SIZE); 77 hdr->conn_id = conn_id; 78 hdr->rfu = 0; 79 hdr->plen = plen; 80 81 nci_mt_set((__u8 *)hdr, NCI_MT_DATA_PKT); 82 nci_pbf_set((__u8 *)hdr, pbf); 83 } 84 85 int nci_conn_max_data_pkt_payload_size(struct nci_dev *ndev, __u8 conn_id) 86 { 87 const struct nci_conn_info *conn_info; 88 89 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id); 90 if (!conn_info) 91 return -EPROTO; 92 93 return conn_info->max_pkt_payload_len; 94 } 95 EXPORT_SYMBOL(nci_conn_max_data_pkt_payload_size); 96 97 static int nci_queue_tx_data_frags(struct nci_dev *ndev, 98 __u8 conn_id, 99 struct sk_buff *skb) { 100 const struct nci_conn_info *conn_info; 101 int total_len = skb->len; 102 const unsigned char *data = skb->data; 103 unsigned long flags; 104 struct sk_buff_head frags_q; 105 struct sk_buff *skb_frag; 106 int frag_len; 107 int rc = 0; 108 109 pr_debug("conn_id 0x%x, total_len %d\n", conn_id, total_len); 110 111 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id); 112 if (!conn_info) { 113 rc = -EPROTO; 114 goto exit; 115 } 116 117 __skb_queue_head_init(&frags_q); 118 119 while (total_len) { 120 frag_len = 121 min_t(int, total_len, conn_info->max_pkt_payload_len); 122 123 skb_frag = nci_skb_alloc(ndev, 124 (NCI_DATA_HDR_SIZE + frag_len), 125 GFP_ATOMIC); 126 if (skb_frag == NULL) { 127 rc = -ENOMEM; 128 goto free_exit; 129 } 130 skb_reserve(skb_frag, NCI_DATA_HDR_SIZE); 131 132 /* first, copy the data */ 133 skb_put_data(skb_frag, data, frag_len); 134 135 /* second, set the header */ 136 nci_push_data_hdr(ndev, conn_id, skb_frag, 137 ((total_len == frag_len) ? 138 (NCI_PBF_LAST) : (NCI_PBF_CONT))); 139 140 __skb_queue_tail(&frags_q, skb_frag); 141 142 data += frag_len; 143 total_len -= frag_len; 144 145 pr_debug("frag_len %d, remaining total_len %d\n", 146 frag_len, total_len); 147 } 148 149 /* queue all fragments atomically */ 150 spin_lock_irqsave(&ndev->tx_q.lock, flags); 151 152 while ((skb_frag = __skb_dequeue(&frags_q)) != NULL) 153 __skb_queue_tail(&ndev->tx_q, skb_frag); 154 155 spin_unlock_irqrestore(&ndev->tx_q.lock, flags); 156 157 /* free the original skb */ 158 kfree_skb(skb); 159 160 goto exit; 161 162 free_exit: 163 while ((skb_frag = __skb_dequeue(&frags_q)) != NULL) 164 kfree_skb(skb_frag); 165 166 exit: 167 return rc; 168 } 169 170 /* Send NCI data */ 171 int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb) 172 { 173 const struct nci_conn_info *conn_info; 174 int rc = 0; 175 176 pr_debug("conn_id 0x%x, plen %d\n", conn_id, skb->len); 177 178 conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id); 179 if (!conn_info) { 180 rc = -EPROTO; 181 goto free_exit; 182 } 183 184 /* check if the packet need to be fragmented */ 185 if (skb->len <= conn_info->max_pkt_payload_len) { 186 /* no need to fragment packet */ 187 nci_push_data_hdr(ndev, conn_id, skb, NCI_PBF_LAST); 188 189 skb_queue_tail(&ndev->tx_q, skb); 190 } else { 191 /* fragment packet and queue the fragments */ 192 rc = nci_queue_tx_data_frags(ndev, conn_id, skb); 193 if (rc) { 194 pr_err("failed to fragment tx data packet\n"); 195 goto free_exit; 196 } 197 } 198 199 ndev->cur_conn_id = conn_id; 200 queue_work(ndev->tx_wq, &ndev->tx_work); 201 202 goto exit; 203 204 free_exit: 205 kfree_skb(skb); 206 207 exit: 208 return rc; 209 } 210 EXPORT_SYMBOL(nci_send_data); 211 212 /* ----------------- NCI RX Data ----------------- */ 213 214 static void nci_add_rx_data_frag(struct nci_dev *ndev, 215 struct sk_buff *skb, 216 __u8 pbf, __u8 conn_id, __u8 status) 217 { 218 int reassembly_len; 219 int err = 0; 220 221 if (status) { 222 err = status; 223 goto exit; 224 } 225 226 if (ndev->rx_data_reassembly) { 227 reassembly_len = ndev->rx_data_reassembly->len; 228 229 /* first, make enough room for the already accumulated data */ 230 if (skb_cow_head(skb, reassembly_len)) { 231 pr_err("error adding room for accumulated rx data\n"); 232 233 kfree_skb(skb); 234 skb = NULL; 235 236 kfree_skb(ndev->rx_data_reassembly); 237 ndev->rx_data_reassembly = NULL; 238 239 err = -ENOMEM; 240 goto exit; 241 } 242 243 /* second, combine the two fragments */ 244 memcpy(skb_push(skb, reassembly_len), 245 ndev->rx_data_reassembly->data, 246 reassembly_len); 247 248 /* third, free old reassembly */ 249 kfree_skb(ndev->rx_data_reassembly); 250 ndev->rx_data_reassembly = NULL; 251 } 252 253 if (pbf == NCI_PBF_CONT) { 254 /* need to wait for next fragment, store skb and exit */ 255 ndev->rx_data_reassembly = skb; 256 return; 257 } 258 259 exit: 260 if (ndev->nfc_dev->rf_mode == NFC_RF_TARGET) { 261 /* Data received in Target mode, forward to nfc core */ 262 err = nfc_tm_data_received(ndev->nfc_dev, skb); 263 if (err) 264 pr_err("unable to handle received data\n"); 265 } else { 266 nci_data_exchange_complete(ndev, skb, conn_id, err); 267 } 268 } 269 270 /* Rx Data packet */ 271 void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb) 272 { 273 __u8 pbf = nci_pbf(skb->data); 274 __u8 status = 0; 275 __u8 conn_id = nci_conn_id(skb->data); 276 const struct nci_conn_info *conn_info; 277 278 pr_debug("len %d\n", skb->len); 279 280 pr_debug("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d\n", 281 nci_pbf(skb->data), 282 nci_conn_id(skb->data), 283 nci_plen(skb->data)); 284 285 conn_info = nci_get_conn_info_by_conn_id(ndev, nci_conn_id(skb->data)); 286 if (!conn_info) { 287 kfree_skb(skb); 288 return; 289 } 290 291 /* strip the nci data header */ 292 skb_pull(skb, NCI_DATA_HDR_SIZE); 293 294 if (ndev->target_active_prot == NFC_PROTO_MIFARE || 295 ndev->target_active_prot == NFC_PROTO_JEWEL || 296 ndev->target_active_prot == NFC_PROTO_FELICA || 297 ndev->target_active_prot == NFC_PROTO_ISO15693) { 298 /* frame I/F => remove the status byte */ 299 pr_debug("frame I/F => remove the status byte\n"); 300 status = skb->data[skb->len - 1]; 301 skb_trim(skb, (skb->len - 1)); 302 } 303 304 nci_add_rx_data_frag(ndev, skb, pbf, conn_id, nci_to_errno(status)); 305 } 306