net/nfc/nci/data.c

   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 = 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 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                 skb_put_data(skb_frag, 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 }