LXR linux/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 */
  38void 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
  70exit:
  71        clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
  72}
  73
  74/* ----------------- NCI TX Data ----------------- */
  75
  76static 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
  93int 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}
 103EXPORT_SYMBOL(nci_conn_max_data_pkt_payload_size);
 104
 105static 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 free_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                memcpy(skb_put(skb_frag, frag_len), 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
 170free_exit:
 171        while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
 172                kfree_skb(skb_frag);
 173
 174exit:
 175        return rc;
 176}
 177
 178/* Send NCI data */
 179int 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
 212free_exit:
 213        kfree_skb(skb);
 214
 215exit:
 216        return rc;
 217}
 218EXPORT_SYMBOL(nci_send_data);
 219
 220/* ----------------- NCI RX Data ----------------- */
 221
 222static 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
 267exit:
 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 */
 279void 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}
 312