// SPDX-License-Identifier: GPL-2.0-only
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/*
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* The NFC Controller Interface is the communication protocol between an
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* NFC Controller (NFCC) and a Device Host (DH).
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*
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* Copyright (C) 2011 Texas Instruments, Inc.
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* Copyright (C) 2014 Marvell International Ltd.
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*
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* Written by Ilan Elias <ilane@ti.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__
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#include <linux/types.h>
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#include <linux/interrupt.h>
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#include <linux/wait.h>
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#include <linux/bitops.h>
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#include <linux/skbuff.h>
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#include "../nfc.h"
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#include <net/nfc/nci.h>
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#include <net/nfc/nci_core.h>
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#include <linux/nfc.h>
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/* Complete data exchange transaction and forward skb to nfc core */
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void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb,
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__u8 conn_id, int err)
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{
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struct nci_conn_info *conn_info;
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data_exchange_cb_t cb;
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void *cb_context;
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conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
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if (!conn_info) {
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kfree_skb(skb);
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goto exit;
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}
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cb = conn_info->data_exchange_cb;
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cb_context = conn_info->data_exchange_cb_context;
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pr_debug("len %d, err %d\n", skb ? skb->len : 0, err);
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/* data exchange is complete, stop the data timer */
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del_timer_sync(&ndev->data_timer);
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clear_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags);
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if (cb) {
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/* forward skb to nfc core */
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cb(cb_context, skb, err);
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} else if (skb) {
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pr_err("no rx callback, dropping rx data...\n");
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/* no waiting callback, free skb */
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kfree_skb(skb);
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}
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exit:
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clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
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}
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/* ----------------- NCI TX Data ----------------- */
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static inline void nci_push_data_hdr(struct nci_dev *ndev,
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__u8 conn_id,
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struct sk_buff *skb,
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__u8 pbf)
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{
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struct nci_data_hdr *hdr;
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int plen = skb->len;
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hdr = skb_push(skb, NCI_DATA_HDR_SIZE);
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hdr->conn_id = conn_id;
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hdr->rfu = 0;
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hdr->plen = plen;
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nci_mt_set((__u8 *)hdr, NCI_MT_DATA_PKT);
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nci_pbf_set((__u8 *)hdr, pbf);
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}
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int nci_conn_max_data_pkt_payload_size(struct nci_dev *ndev, __u8 conn_id)
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{
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struct nci_conn_info *conn_info;
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conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
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if (!conn_info)
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return -EPROTO;
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return conn_info->max_pkt_payload_len;
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}
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EXPORT_SYMBOL(nci_conn_max_data_pkt_payload_size);
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static int nci_queue_tx_data_frags(struct nci_dev *ndev,
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__u8 conn_id,
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struct sk_buff *skb) {
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struct nci_conn_info *conn_info;
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int total_len = skb->len;
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unsigned char *data = skb->data;
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unsigned long flags;
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struct sk_buff_head frags_q;
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struct sk_buff *skb_frag;
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int frag_len;
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int rc = 0;
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pr_debug("conn_id 0x%x, total_len %d\n", conn_id, total_len);
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conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
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if (!conn_info) {
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rc = -EPROTO;
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goto exit;
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}
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__skb_queue_head_init(&frags_q);
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while (total_len) {
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frag_len =
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min_t(int, total_len, conn_info->max_pkt_payload_len);
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skb_frag = nci_skb_alloc(ndev,
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(NCI_DATA_HDR_SIZE + frag_len),
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GFP_ATOMIC);
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if (skb_frag == NULL) {
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rc = -ENOMEM;
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goto free_exit;
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}
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skb_reserve(skb_frag, NCI_DATA_HDR_SIZE);
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/* first, copy the data */
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skb_put_data(skb_frag, data, frag_len);
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/* second, set the header */
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nci_push_data_hdr(ndev, conn_id, skb_frag,
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((total_len == frag_len) ?
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(NCI_PBF_LAST) : (NCI_PBF_CONT)));
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__skb_queue_tail(&frags_q, skb_frag);
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data += frag_len;
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total_len -= frag_len;
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pr_debug("frag_len %d, remaining total_len %d\n",
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frag_len, total_len);
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}
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/* queue all fragments atomically */
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spin_lock_irqsave(&ndev->tx_q.lock, flags);
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while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
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__skb_queue_tail(&ndev->tx_q, skb_frag);
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spin_unlock_irqrestore(&ndev->tx_q.lock, flags);
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/* free the original skb */
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kfree_skb(skb);
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goto exit;
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free_exit:
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while ((skb_frag = __skb_dequeue(&frags_q)) != NULL)
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kfree_skb(skb_frag);
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exit:
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return rc;
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}
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/* Send NCI data */
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int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb)
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{
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struct nci_conn_info *conn_info;
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int rc = 0;
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pr_debug("conn_id 0x%x, plen %d\n", conn_id, skb->len);
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conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
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if (!conn_info) {
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rc = -EPROTO;
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goto free_exit;
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}
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/* check if the packet need to be fragmented */
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if (skb->len <= conn_info->max_pkt_payload_len) {
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/* no need to fragment packet */
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nci_push_data_hdr(ndev, conn_id, skb, NCI_PBF_LAST);
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skb_queue_tail(&ndev->tx_q, skb);
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} else {
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/* fragment packet and queue the fragments */
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rc = nci_queue_tx_data_frags(ndev, conn_id, skb);
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if (rc) {
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pr_err("failed to fragment tx data packet\n");
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goto free_exit;
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}
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}
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ndev->cur_conn_id = conn_id;
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queue_work(ndev->tx_wq, &ndev->tx_work);
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goto exit;
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free_exit:
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kfree_skb(skb);
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exit:
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return rc;
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}
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EXPORT_SYMBOL(nci_send_data);
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/* ----------------- NCI RX Data ----------------- */
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static void nci_add_rx_data_frag(struct nci_dev *ndev,
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struct sk_buff *skb,
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__u8 pbf, __u8 conn_id, __u8 status)
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{
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int reassembly_len;
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int err = 0;
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if (status) {
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err = status;
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goto exit;
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}
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if (ndev->rx_data_reassembly) {
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reassembly_len = ndev->rx_data_reassembly->len;
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/* first, make enough room for the already accumulated data */
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if (skb_cow_head(skb, reassembly_len)) {
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pr_err("error adding room for accumulated rx data\n");
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kfree_skb(skb);
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skb = NULL;
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kfree_skb(ndev->rx_data_reassembly);
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ndev->rx_data_reassembly = NULL;
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err = -ENOMEM;
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goto exit;
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}
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/* second, combine the two fragments */
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memcpy(skb_push(skb, reassembly_len),
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ndev->rx_data_reassembly->data,
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reassembly_len);
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/* third, free old reassembly */
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kfree_skb(ndev->rx_data_reassembly);
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ndev->rx_data_reassembly = NULL;
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}
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if (pbf == NCI_PBF_CONT) {
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/* need to wait for next fragment, store skb and exit */
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ndev->rx_data_reassembly = skb;
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return;
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}
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exit:
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if (ndev->nfc_dev->rf_mode == NFC_RF_TARGET) {
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/* Data received in Target mode, forward to nfc core */
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err = nfc_tm_data_received(ndev->nfc_dev, skb);
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if (err)
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pr_err("unable to handle received data\n");
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} else {
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nci_data_exchange_complete(ndev, skb, conn_id, err);
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}
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}
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/* Rx Data packet */
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void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb)
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{
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__u8 pbf = nci_pbf(skb->data);
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__u8 status = 0;
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__u8 conn_id = nci_conn_id(skb->data);
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struct nci_conn_info *conn_info;
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pr_debug("len %d\n", skb->len);
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pr_debug("NCI RX: MT=data, PBF=%d, conn_id=%d, plen=%d\n",
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nci_pbf(skb->data),
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nci_conn_id(skb->data),
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nci_plen(skb->data));
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conn_info = nci_get_conn_info_by_conn_id(ndev, nci_conn_id(skb->data));
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if (!conn_info) {
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kfree_skb(skb);
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return;
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}
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/* strip the nci data header */
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skb_pull(skb, NCI_DATA_HDR_SIZE);
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if (ndev->target_active_prot == NFC_PROTO_MIFARE ||
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ndev->target_active_prot == NFC_PROTO_JEWEL ||
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ndev->target_active_prot == NFC_PROTO_FELICA ||
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ndev->target_active_prot == NFC_PROTO_ISO15693) {
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/* frame I/F => remove the status byte */
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pr_debug("frame I/F => remove the status byte\n");
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status = skb->data[skb->len - 1];
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skb_trim(skb, (skb->len - 1));
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}
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nci_add_rx_data_frag(ndev, skb, pbf, conn_id, nci_to_errno(status));
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}
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