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 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 58 exit: 59 clear_bit(NCI_DATA_EXCHANGE, &ndev->flags); 60 } 61 62 /* ----------------- NCI TX Data ----------------- */ 63 64 static 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 81 int 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 } 91 EXPORT_SYMBOL(nci_conn_max_data_pkt_payload_size); 92 93 static 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; 157 158 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 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; 199 200 free_exit: 201 kfree_skb(skb); 202 203 exit: 204 return rc; 205 } 206 EXPORT_SYMBOL(nci_send_data); 207 208 /* ----------------- NCI RX Data ----------------- */ 209 210 static 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 } 254 255 exit: 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 */ 267 void 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