diff options
Diffstat (limited to 'net/nfc/nci/data.c')
| -rw-r--r-- | net/nfc/nci/data.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/net/nfc/nci/data.c b/net/nfc/nci/data.c new file mode 100644 index 000000000000..e5ed90fc1a9c --- /dev/null +++ b/net/nfc/nci/data.c @@ -0,0 +1,247 @@ +/* + * 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 + * + */ + +#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; + + nfc_dbg("entry, len %d, err %d", ((skb) ? (skb->len) : (0)), err); + + if (cb) { + ndev->data_exchange_cb = NULL; + ndev->data_exchange_cb_context = 0; + + /* forward skb to nfc core */ + cb(cb_context, skb, err); + } else if (skb) { + nfc_err("no rx callback, dropping rx data..."); + + /* 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; + + nfc_dbg("entry, conn_id 0x%x, total_len %d", conn_id, total_len); + + __skb_queue_head_init(&frags_q); + + while (total_len) { + frag_len = min_t(int, total_len, ndev->max_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; + + nfc_dbg("frag_len %d, remaining total_len %d", + 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; + + nfc_dbg("entry, conn_id 0x%x, plen %d", conn_id, skb->len); + + /* check if the packet need to be fragmented */ + if (skb->len <= ndev->max_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) { + nfc_err("failed to fragment tx data packet"); + 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)) { + nfc_err("error adding room for accumulated rx data"); + + kfree_skb(skb); + skb = 0; + + kfree_skb(ndev->rx_data_reassembly); + ndev->rx_data_reassembly = 0; + + 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 = 0; + } + + 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); + + nfc_dbg("entry, len %d", skb->len); + + nfc_dbg("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d", + 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 */ + nfc_dbg("NFC_PROTO_MIFARE => remove the status byte"); + skb_trim(skb, (skb->len - 1)); + } + + nci_add_rx_data_frag(ndev, skb, pbf); +} |