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 = (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 static int nci_queue_tx_data_frags(struct nci_dev *ndev,
  94                                    __u8 conn_id,
  95                                    struct sk_buff *skb) {
  96         struct nci_conn_info    *conn_info;
  97         int total_len = skb->len;
  98         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 free_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_KERNEL);
 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                 memcpy(skb_put(skb_frag, frag_len), 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         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
 207 /* ----------------- NCI RX Data ----------------- */
 208
 209 static void nci_add_rx_data_frag(struct nci_dev *ndev,
 210                                  struct sk_buff *skb,
 211                                  __u8 pbf, __u8 conn_id, __u8 status)
 212 {
 213         int reassembly_len;
 214         int err = 0;
 215
 216         if (status) {
 217                 err = status;
 218                 goto exit;
 219         }
 220
 221         if (ndev->rx_data_reassembly) {
 222                 reassembly_len = ndev->rx_data_reassembly->len;
 223
 224                 /* first, make enough room for the already accumulated data */
 225                 if (skb_cow_head(skb, reassembly_len)) {
 226                         pr_err("error adding room for accumulated rx data\n");
 227
 228                         kfree_skb(skb);
 229                         skb = NULL;
 230
 231                         kfree_skb(ndev->rx_data_reassembly);
 232                         ndev->rx_data_reassembly = NULL;
 233
 234                         err = -ENOMEM;
 235                         goto exit;
 236                 }
 237
 238                 /* second, combine the two fragments */
 239                 memcpy(skb_push(skb, reassembly_len),
 240                        ndev->rx_data_reassembly->data,
 241                        reassembly_len);
 242
 243                 /* third, free old reassembly */
 244                 kfree_skb(ndev->rx_data_reassembly);
 245                 ndev->rx_data_reassembly = NULL;
 246         }
 247
 248         if (pbf == NCI_PBF_CONT) {
 249                 /* need to wait for next fragment, store skb and exit */
 250                 ndev->rx_data_reassembly = skb;
 251                 return;
 252         }
 253
 254 exit:
 255         if (ndev->nfc_dev->rf_mode == NFC_RF_TARGET) {
 256                 /* Data received in Target mode, forward to nfc core */
 257                 err = nfc_tm_data_received(ndev->nfc_dev, skb);
 258                 if (err)
 259                         pr_err("unable to handle received data\n");
 260         } else {
 261                 nci_data_exchange_complete(ndev, skb, conn_id, err);
 262         }
 263 }
 264
 265 /* Rx Data packet */
 266 void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb)
 267 {
 268         __u8 pbf = nci_pbf(skb->data);
 269         __u8 status = 0;
 270         __u8 conn_id = nci_conn_id(skb->data);
 271         struct nci_conn_info    *conn_info;
 272
 273         pr_debug("len %d\n", skb->len);
 274
 275         pr_debug("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d\n",
 276                  nci_pbf(skb->data),
 277                  nci_conn_id(skb->data),
 278                  nci_plen(skb->data));
 279
 280         conn_info = nci_get_conn_info_by_conn_id(ndev, nci_conn_id(skb->data));
 281         if (!conn_info)
 282                 return;
 283
 284         /* strip the nci data header */
 285         skb_pull(skb, NCI_DATA_HDR_SIZE);
 286
 287         if (ndev->target_active_prot == NFC_PROTO_MIFARE ||
 288             ndev->target_active_prot == NFC_PROTO_JEWEL ||
 289             ndev->target_active_prot == NFC_PROTO_FELICA ||
 290             ndev->target_active_prot == NFC_PROTO_ISO15693) {
 291                 /* frame I/F => remove the status byte */
 292                 pr_debug("frame I/F => remove the status byte\n");
 293                 status = skb->data[skb->len - 1];
 294                 skb_trim(skb, (skb->len - 1));
 295         }
 296
 297         nci_add_rx_data_frag(ndev, skb, pbf, conn_id, nci_to_errno(status));
 298 }