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                                int err)
  40{
  41        data_exchange_cb_t cb = ndev->data_exchange_cb;
  42        void *cb_context = ndev->data_exchange_cb_context;
  43
  44        pr_debug("len %d, err %d\n", skb ? skb->len : 0, err);
  45
  46        /* data exchange is complete, stop the data timer */
  47        del_timer_sync(&ndev->data_timer);
  48        clear_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags);
  49
  50        if (cb) {
  51                ndev->data_exchange_cb = NULL;
  52                ndev->data_exchange_cb_context = NULL;
  53
  54                /* forward skb to nfc core */
  55                cb(cb_context, skb, err);
  56        } else if (skb) {
  57                pr_err("no rx callback, dropping rx data...\n");
  58
  59                /* no waiting callback, free skb */
  60                kfree_skb(skb);
  61        }
  62
  63        clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
  64}
  65
  66/* ----------------- NCI TX Data ----------------- */
  67
  68static inline void nci_push_data_hdr(struct nci_dev *ndev,
  69                                     __u8 conn_id,
  70                                     struct sk_buff *skb,
  71                                     __u8 pbf)
  72{
  73        struct nci_data_hdr *hdr;
  74        int plen = skb->len;
  75
  76        hdr = (struct nci_data_hdr *) skb_push(skb, NCI_DATA_HDR_SIZE);
  77        hdr->conn_id = conn_id;
  78        hdr->rfu = 0;
  79        hdr->plen = plen;
  80
  81        nci_mt_set((__u8 *)hdr, NCI_MT_DATA_PKT);
  82        nci_pbf_set((__u8 *)hdr, pbf);
  83}
  84
  85static int nci_queue_tx_data_frags(struct nci_dev *ndev,
  86                                   __u8 conn_id,
  87                                   struct sk_buff *skb) {
  88        int total_len = skb->len;
  89        unsigned char *data = skb->data;
  90        unsigned long flags;
  91        struct sk_buff_head frags_q;
  92        struct sk_buff *skb_frag;
  93        int frag_len;
  94        int rc = 0;
  95
  96        pr_debug("conn_id 0x%x, total_len %d\n", conn_id, total_len);
  97
  98        __skb_queue_head_init(&frags_q);
  99
 100        while (total_len) {
 101                frag_len =
 102                        min_t(int, total_len, ndev->max_data_pkt_payload_size);
 103
 104                skb_frag = nci_skb_alloc(ndev,
 105                                         (NCI_DATA_HDR_SIZE + frag_len),
 106                                         GFP_KERNEL);
 107                if (skb_frag == NULL) {
 108                        rc = -ENOMEM;
 109                        goto free_exit;
 110                }
 111                skb_reserve(skb_frag, NCI_DATA_HDR_SIZE);
 112
 113                /* first, copy the data */
 114                memcpy(skb_put(skb_frag, frag_len), data, frag_len);
 115
 116                /* second, set the header */
 117                nci_push_data_hdr(ndev, conn_id, skb_frag,
 118                                  ((total_len == frag_len) ?
 119                                   (NCI_PBF_LAST) : (NCI_PBF_CONT)));
 120
 121                __skb_queue_tail(&frags_q, skb_frag);
 122
 123                data += frag_len;
 124                total_len -= frag_len;
 125
 126                pr_debug("frag_len %d, remaining total_len %d\n",
 127                         frag_len, total_len);
 128        }
 129
 130        /* queue all fragments atomically */
 131        spin_lock_irqsave(&ndev->tx_q.lock, flags);
 132
 133        while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
 134                __skb_queue_tail(&ndev->tx_q, skb_frag);
 135
 136        spin_unlock_irqrestore(&ndev->tx_q.lock, flags);
 137
 138        /* free the original skb */
 139        kfree_skb(skb);
 140
 141        goto exit;
 142
 143free_exit:
 144        while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
 145                kfree_skb(skb_frag);
 146
 147exit:
 148        return rc;
 149}
 150
 151/* Send NCI data */
 152int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb)
 153{
 154        int rc = 0;
 155
 156        pr_debug("conn_id 0x%x, plen %d\n", conn_id, skb->len);
 157
 158        /* check if the packet need to be fragmented */
 159        if (skb->len <= ndev->max_data_pkt_payload_size) {
 160                /* no need to fragment packet */
 161                nci_push_data_hdr(ndev, conn_id, skb, NCI_PBF_LAST);
 162
 163                skb_queue_tail(&ndev->tx_q, skb);
 164        } else {
 165                /* fragment packet and queue the fragments */
 166                rc = nci_queue_tx_data_frags(ndev, conn_id, skb);
 167                if (rc) {
 168                        pr_err("failed to fragment tx data packet\n");
 169                        goto free_exit;
 170                }
 171        }
 172
 173        queue_work(ndev->tx_wq, &ndev->tx_work);
 174
 175        goto exit;
 176
 177free_exit:
 178        kfree_skb(skb);
 179
 180exit:
 181        return rc;
 182}
 183
 184/* ----------------- NCI RX Data ----------------- */
 185
 186static void nci_add_rx_data_frag(struct nci_dev *ndev,
 187                                 struct sk_buff *skb,
 188                                 __u8 pbf, __u8 status)
 189{
 190        int reassembly_len;
 191        int err = 0;
 192
 193        if (status) {
 194                err = status;
 195                goto exit;
 196        }
 197
 198        if (ndev->rx_data_reassembly) {
 199                reassembly_len = ndev->rx_data_reassembly->len;
 200
 201                /* first, make enough room for the already accumulated data */
 202                if (skb_cow_head(skb, reassembly_len)) {
 203                        pr_err("error adding room for accumulated rx data\n");
 204
 205                        kfree_skb(skb);
 206                        skb = NULL;
 207
 208                        kfree_skb(ndev->rx_data_reassembly);
 209                        ndev->rx_data_reassembly = NULL;
 210
 211                        err = -ENOMEM;
 212                        goto exit;
 213                }
 214
 215                /* second, combine the two fragments */
 216                memcpy(skb_push(skb, reassembly_len),
 217                       ndev->rx_data_reassembly->data,
 218                       reassembly_len);
 219
 220                /* third, free old reassembly */
 221                kfree_skb(ndev->rx_data_reassembly);
 222                ndev->rx_data_reassembly = NULL;
 223        }
 224
 225        if (pbf == NCI_PBF_CONT) {
 226                /* need to wait for next fragment, store skb and exit */
 227                ndev->rx_data_reassembly = skb;
 228                return;
 229        }
 230
 231exit:
 232        if (ndev->nfc_dev->rf_mode == NFC_RF_INITIATOR) {
 233                nci_data_exchange_complete(ndev, skb, err);
 234        } else if (ndev->nfc_dev->rf_mode == NFC_RF_TARGET) {
 235                /* Data received in Target mode, forward to nfc core */
 236                err = nfc_tm_data_received(ndev->nfc_dev, skb);
 237                if (err)
 238                        pr_err("unable to handle received data\n");
 239        } else {
 240                pr_err("rf mode unknown\n");
 241                kfree_skb(skb);
 242        }
 243}
 244
 245/* Rx Data packet */
 246void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb)
 247{
 248        __u8 pbf = nci_pbf(skb->data);
 249        __u8 status = 0;
 250
 251        pr_debug("len %d\n", skb->len);
 252
 253        pr_debug("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d\n",
 254                 nci_pbf(skb->data),
 255                 nci_conn_id(skb->data),
 256                 nci_plen(skb->data));
 257
 258        /* strip the nci data header */
 259        skb_pull(skb, NCI_DATA_HDR_SIZE);
 260
 261        if (ndev->target_active_prot == NFC_PROTO_MIFARE ||
 262            ndev->target_active_prot == NFC_PROTO_JEWEL ||
 263            ndev->target_active_prot == NFC_PROTO_FELICA ||
 264            ndev->target_active_prot == NFC_PROTO_ISO15693) {
 265                /* frame I/F => remove the status byte */
 266                pr_debug("frame I/F => remove the status byte\n");
 267                status = skb->data[skb->len - 1];
 268                skb_trim(skb, (skb->len - 1));
 269        }
 270
 271        nci_add_rx_data_frag(ndev, skb, pbf, nci_to_errno(status));
 272}
 273