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
  93static 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
 158free_exit:
 159        while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
 160                kfree_skb(skb_frag);
 161
 162exit:
 163        return rc;
 164}
 165
 166/* Send NCI data */
 167int 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
 200free_exit:
 201        kfree_skb(skb);
 202
 203exit:
 204        return rc;
 205}
 206
 207/* ----------------- NCI RX Data ----------------- */
 208
 209static 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
 254exit:
 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 */
 266void 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}
 299