/*
* The NFC Controller Interface is the communication protocol between an
* NFC Controller (NFCC) and a Device Host (DH).
*
* Copyright (C) 2011 Texas Instruments, Inc.
*
* Written by Ilan Elias <ilane@ti.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/bitops.h>
#include <linux/skbuff.h>
#include "../nfc.h"
#include <net/nfc/nci.h>
#include <net/nfc/nci_core.h>
#include <linux/nfc.h>
/* Complete data exchange transaction and forward skb to nfc core */
void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb,
int err)
{
data_exchange_cb_t cb = ndev->data_exchange_cb;
void *cb_context = ndev->data_exchange_cb_context;
pr_debug("len %d, err %d\n", skb ? skb->len : 0, err);
/* data exchange is complete, stop the data timer */
del_timer_sync(&ndev->data_timer);
clear_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags);
if (cb) {
ndev->data_exchange_cb = NULL;
ndev->data_exchange_cb_context = NULL;
/* forward skb to nfc core */
cb(cb_context, skb, err);
} else if (skb) {
pr_err("no rx callback, dropping rx data...\n");
/* no waiting callback, free skb */
kfree_skb(skb);
}
clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
}
/* ----------------- NCI TX Data ----------------- */
static inline void nci_push_data_hdr(struct nci_dev *ndev,
__u8 conn_id,
struct sk_buff *skb,
__u8 pbf)
{
struct nci_data_hdr *hdr;
int plen = skb->len;
hdr = (struct nci_data_hdr *) skb_push(skb, NCI_DATA_HDR_SIZE);
hdr->conn_id = conn_id;
hdr->rfu = 0;
hdr->plen = plen;
nci_mt_set((__u8 *)hdr, NCI_MT_DATA_PKT);
nci_pbf_set((__u8 *)hdr, pbf);
skb->dev = (void *) ndev;
}
static int nci_queue_tx_data_frags(struct nci_dev *ndev,
__u8 conn_id,
struct sk_buff *skb) {
int total_len = skb->len;
unsigned char *data = skb->data;
unsigned long flags;
struct sk_buff_head frags_q;
struct sk_buff *skb_frag;
int frag_len;
int rc = 0;
pr_debug("conn_id 0x%x, total_len %d\n", conn_id, total_len);
__skb_queue_head_init(&frags_q);
while (total_len) {
frag_len =
min_t(int, total_len, ndev->max_data_pkt_payload_size);
skb_frag = nci_skb_alloc(ndev,
(NCI_DATA_HDR_SIZE + frag_len),
GFP_KERNEL);
if (skb_frag == NULL) {
rc = -ENOMEM;
goto free_exit;
}
skb_reserve(skb_frag, NCI_DATA_HDR_SIZE);
/* first, copy the data */
memcpy(skb_put(skb_frag, frag_len), data, frag_len);
/* second, set the header */
nci_push_data_hdr(ndev, conn_id, skb_frag,
((total_len == frag_len) ?
(NCI_PBF_LAST) : (NCI_PBF_CONT)));
__skb_queue_tail(&frags_q, skb_frag);
data += frag_len;
total_len -= frag_len;
pr_debug("frag_len %d, remaining total_len %d\n",
frag_len, total_len);
}
/* queue all fragments atomically */
spin_lock_irqsave(&ndev->tx_q.lock, flags);
while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
__skb_queue_tail(&ndev->tx_q, skb_frag);
spin_unlock_irqrestore(&ndev->tx_q.lock, flags);
/* free the original skb */
kfree_skb(skb);
goto exit;
free_exit:
while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
kfree_skb(skb_frag);
exit:
return rc;
}
/* Send NCI data */
int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb)
{
int rc = 0;
pr_debug("conn_id 0x%x, plen %d\n", conn_id, skb->len);
/* check if the packet need to be fragmented */
if (skb->len <= ndev->max_data_pkt_payload_size) {
/* no need to fragment packet */
nci_push_data_hdr(ndev, conn_id, skb, NCI_PBF_LAST);
skb_queue_tail(&ndev->tx_q, skb);
} else {
/* fragment packet and queue the fragments */
rc = nci_queue_tx_data_frags(ndev, conn_id, skb);
if (rc) {
pr_err("failed to fragment tx data packet\n");
goto free_exit;
}
}
queue_work(ndev->tx_wq, &ndev->tx_work);
goto exit;
free_exit:
kfree_skb(skb);
exit:
return rc;
}
/* ----------------- NCI RX Data ----------------- */
static void nci_add_rx_data_frag(struct nci_dev *ndev,
struct sk_buff *skb,
__u8 pbf)
{
int reassembly_len;
int err = 0;
if (ndev->rx_data_reassembly) {
reassembly_len = ndev->rx_data_reassembly->len;
/* first, make enough room for the already accumulated data */
if (skb_cow_head(skb, reassembly_len)) {
pr_err("error adding room for accumulated rx data\n");
kfree_skb(skb);
skb = NULL;
kfree_skb(ndev->rx_data_reassembly);
ndev->rx_data_reassembly = NULL;
err = -ENOMEM;
goto exit;
}
/* second, combine the two fragments */
memcpy(skb_push(skb, reassembly_len),
ndev->rx_data_reassembly->data,
reassembly_len);
/* third, free old reassembly */
kfree_skb(ndev->rx_data_reassembly);
ndev->rx_data_reassembly = NULL;
}
if (pbf == NCI_PBF_CONT) {
/* need to wait for next fragment, store skb and exit */
ndev->rx_data_reassembly = skb;
return;
}
exit:
nci_data_exchange_complete(ndev, skb, err);
}
/* Rx Data packet */
void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb)
{
__u8 pbf = nci_pbf(skb->data);
pr_debug("len %d\n", skb->len);
pr_debug("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d\n",
nci_pbf(skb->data),
nci_conn_id(skb->data),
nci_plen(skb->data));
/* strip the nci data header */
skb_pull(skb, NCI_DATA_HDR_SIZE);
if (ndev->target_active_prot == NFC_PROTO_MIFARE) {
/* frame I/F => remove the status byte */
pr_debug("NFC_PROTO_MIFARE => remove the status byte\n");
skb_trim(skb, (skb->len - 1));
}
nci_add_rx_data_frag(ndev, skb, pbf);
}