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 * 7 * Written by Ilan Elias <ilane@ti.com> 8 * 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 12 * 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. 17 * 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 21 * 22 */ 23 24 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 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, 39 struct sk_buff *skb, 40 int err) 41 { 42 data_exchange_cb_t cb = ndev->data_exchange_cb; 43 void *cb_context = ndev->data_exchange_cb_context; 44 45 pr_debug("len %d, err %d\n", skb ? skb->len : 0, err); 46 47 if (cb) { 48 ndev->data_exchange_cb = NULL; 49 ndev->data_exchange_cb_context = 0; 50 51 /* forward skb to nfc core */ 52 cb(cb_context, skb, err); 53 } else if (skb) { 54 pr_err("no rx callback, dropping rx data...\n"); 55 56 /* no waiting callback, free skb */ 57 kfree_skb(skb); 58 } 59 60 clear_bit(NCI_DATA_EXCHANGE, &ndev->flags); 61 } 62 63 /* ----------------- NCI TX Data ----------------- */ 64 65 static inline void nci_push_data_hdr(struct nci_dev *ndev, 66 __u8 conn_id, 67 struct sk_buff *skb, 68 __u8 pbf) 69 { 70 struct nci_data_hdr *hdr; 71 int plen = skb->len; 72 73 hdr = (struct nci_data_hdr *) skb_push(skb, NCI_DATA_HDR_SIZE); 74 hdr->conn_id = conn_id; 75 hdr->rfu = 0; 76 hdr->plen = plen; 77 78 nci_mt_set((__u8 *)hdr, NCI_MT_DATA_PKT); 79 nci_pbf_set((__u8 *)hdr, pbf); 80 81 skb->dev = (void *) ndev; 82 } 83 84 static int nci_queue_tx_data_frags(struct nci_dev *ndev, 85 __u8 conn_id, 86 struct sk_buff *skb) { 87 int total_len = skb->len; 88 unsigned char *data = skb->data; 89 unsigned long flags; 90 struct sk_buff_head frags_q; 91 struct sk_buff *skb_frag; 92 int frag_len; 93 int rc = 0; 94 95 pr_debug("conn_id 0x%x, total_len %d\n", conn_id, total_len); 96 97 __skb_queue_head_init(&frags_q); 98 99 while (total_len) { 100 frag_len = 101 min_t(int, total_len, ndev->max_data_pkt_payload_size); 102 103 skb_frag = nci_skb_alloc(ndev, 104 (NCI_DATA_HDR_SIZE + frag_len), 105 GFP_KERNEL); 106 if (skb_frag == NULL) { 107 rc = -ENOMEM; 108 goto free_exit; 109 } 110 skb_reserve(skb_frag, NCI_DATA_HDR_SIZE); 111 112 /* first, copy the data */ 113 memcpy(skb_put(skb_frag, frag_len), data, frag_len); 114 115 /* second, set the header */ 116 nci_push_data_hdr(ndev, conn_id, skb_frag, 117 ((total_len == frag_len) ? (NCI_PBF_LAST) : (NCI_PBF_CONT))); 118 119 __skb_queue_tail(&frags_q, skb_frag); 120 121 data += frag_len; 122 total_len -= frag_len; 123 124 pr_debug("frag_len %d, remaining total_len %d\n", 125 frag_len, total_len); 126 } 127 128 /* queue all fragments atomically */ 129 spin_lock_irqsave(&ndev->tx_q.lock, flags); 130 131 while ((skb_frag = __skb_dequeue(&frags_q)) != NULL) 132 __skb_queue_tail(&ndev->tx_q, skb_frag); 133 134 spin_unlock_irqrestore(&ndev->tx_q.lock, flags); 135 136 /* free the original skb */ 137 kfree_skb(skb); 138 139 goto exit; 140 141 free_exit: 142 while ((skb_frag = __skb_dequeue(&frags_q)) != NULL) 143 kfree_skb(skb_frag); 144 145 exit: 146 return rc; 147 } 148 149 /* Send NCI data */ 150 int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb) 151 { 152 int rc = 0; 153 154 pr_debug("conn_id 0x%x, plen %d\n", conn_id, skb->len); 155 156 /* check if the packet need to be fragmented */ 157 if (skb->len <= ndev->max_data_pkt_payload_size) { 158 /* no need to fragment packet */ 159 nci_push_data_hdr(ndev, conn_id, skb, NCI_PBF_LAST); 160 161 skb_queue_tail(&ndev->tx_q, skb); 162 } else { 163 /* fragment packet and queue the fragments */ 164 rc = nci_queue_tx_data_frags(ndev, conn_id, skb); 165 if (rc) { 166 pr_err("failed to fragment tx data packet\n"); 167 goto free_exit; 168 } 169 } 170 171 queue_work(ndev->tx_wq, &ndev->tx_work); 172 173 goto exit; 174 175 free_exit: 176 kfree_skb(skb); 177 178 exit: 179 return rc; 180 } 181 182 /* ----------------- NCI RX Data ----------------- */ 183 184 static void nci_add_rx_data_frag(struct nci_dev *ndev, 185 struct sk_buff *skb, 186 __u8 pbf) 187 { 188 int reassembly_len; 189 int err = 0; 190 191 if (ndev->rx_data_reassembly) { 192 reassembly_len = ndev->rx_data_reassembly->len; 193 194 /* first, make enough room for the already accumulated data */ 195 if (skb_cow_head(skb, reassembly_len)) { 196 pr_err("error adding room for accumulated rx data\n"); 197 198 kfree_skb(skb); 199 skb = 0; 200 201 kfree_skb(ndev->rx_data_reassembly); 202 ndev->rx_data_reassembly = 0; 203 204 err = -ENOMEM; 205 goto exit; 206 } 207 208 /* second, combine the two fragments */ 209 memcpy(skb_push(skb, reassembly_len), 210 ndev->rx_data_reassembly->data, 211 reassembly_len); 212 213 /* third, free old reassembly */ 214 kfree_skb(ndev->rx_data_reassembly); 215 ndev->rx_data_reassembly = 0; 216 } 217 218 if (pbf == NCI_PBF_CONT) { 219 /* need to wait for next fragment, store skb and exit */ 220 ndev->rx_data_reassembly = skb; 221 return; 222 } 223 224 exit: 225 nci_data_exchange_complete(ndev, skb, err); 226 } 227 228 /* Rx Data packet */ 229 void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb) 230 { 231 __u8 pbf = nci_pbf(skb->data); 232 233 pr_debug("len %d\n", skb->len); 234 235 pr_debug("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d\n", 236 nci_pbf(skb->data), 237 nci_conn_id(skb->data), 238 nci_plen(skb->data)); 239 240 /* strip the nci data header */ 241 skb_pull(skb, NCI_DATA_HDR_SIZE); 242 243 if (ndev->target_active_prot == NFC_PROTO_MIFARE) { 244 /* frame I/F => remove the status byte */ 245 pr_debug("NFC_PROTO_MIFARE => remove the status byte\n"); 246 skb_trim(skb, (skb->len - 1)); 247 } 248 249 nci_add_rx_data_frag(ndev, skb, pbf); 250 } 251