269 lines
7.4 KiB
C
269 lines
7.4 KiB
C
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/*
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* Linux ARCnet driver - "cap mode" packet encapsulation.
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* It adds sequence numbers to packets for communicating between a user space
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* application and the driver. After a transmit it sends a packet with protocol
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* byte 0 back up to the userspace containing the sequence number of the packet
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* plus the transmit-status on the ArcNet.
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*
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* Written 2002-4 by Esben Nielsen, Vestas Wind Systems A/S
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* Derived from arc-rawmode.c by Avery Pennarun.
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* arc-rawmode was in turned based on skeleton.c, see below.
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*
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* **********************
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*
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* The original copyright of skeleton.c was as follows:
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*
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* skeleton.c Written 1993 by Donald Becker.
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* Copyright 1993 United States Government as represented by the
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* Director, National Security Agency. This software may only be used
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* and distributed according to the terms of the GNU General Public License as
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* modified by SRC, incorporated herein by reference.
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*
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* **********************
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*
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* For more details, see drivers/net/arcnet.c
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*
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* **********************
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*/
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#define pr_fmt(fmt) "arcnet:" KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/gfp.h>
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#include <linux/init.h>
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#include <linux/if_arp.h>
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#include <net/arp.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include "arcdevice.h"
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/* packet receiver */
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static void rx(struct net_device *dev, int bufnum,
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struct archdr *pkthdr, int length)
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{
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struct arcnet_local *lp = netdev_priv(dev);
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struct sk_buff *skb;
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struct archdr *pkt;
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char *pktbuf, *pkthdrbuf;
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int ofs;
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arc_printk(D_DURING, dev, "it's a raw(cap) packet (length=%d)\n",
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length);
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if (length >= MinTU)
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ofs = 512 - length;
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else
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ofs = 256 - length;
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skb = alloc_skb(length + ARC_HDR_SIZE + sizeof(int), GFP_ATOMIC);
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if (!skb) {
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dev->stats.rx_dropped++;
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return;
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}
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skb_put(skb, length + ARC_HDR_SIZE + sizeof(int));
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skb->dev = dev;
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skb_reset_mac_header(skb);
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pkt = (struct archdr *)skb_mac_header(skb);
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skb_pull(skb, ARC_HDR_SIZE);
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/* up to sizeof(pkt->soft) has already been copied from the card
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* squeeze in an int for the cap encapsulation
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* use these variables to be sure we count in bytes, not in
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* sizeof(struct archdr)
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*/
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pktbuf = (char *)pkt;
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pkthdrbuf = (char *)pkthdr;
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memcpy(pktbuf, pkthdrbuf, ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto));
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memcpy(pktbuf + ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto) + sizeof(int),
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pkthdrbuf + ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto),
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sizeof(struct archdr) - ARC_HDR_SIZE - sizeof(pkt->soft.cap.proto));
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if (length > sizeof(pkt->soft))
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lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
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pkt->soft.raw + sizeof(pkt->soft)
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+ sizeof(int),
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length - sizeof(pkt->soft));
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if (BUGLVL(D_SKB))
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arcnet_dump_skb(dev, skb, "rx");
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skb->protocol = cpu_to_be16(ETH_P_ARCNET);
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netif_rx(skb);
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}
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/* Create the ARCnet hard/soft headers for cap mode.
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* There aren't any soft headers in cap mode - not even the protocol id.
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*/
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static int build_header(struct sk_buff *skb,
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struct net_device *dev,
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unsigned short type,
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uint8_t daddr)
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{
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int hdr_size = ARC_HDR_SIZE;
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struct archdr *pkt = skb_push(skb, hdr_size);
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arc_printk(D_PROTO, dev, "Preparing header for cap packet %x.\n",
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*((int *)&pkt->soft.cap.cookie[0]));
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/* Set the source hardware address.
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*
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* This is pretty pointless for most purposes, but it can help in
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* debugging. ARCnet does not allow us to change the source address in
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* the actual packet sent)
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*/
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pkt->hard.source = *dev->dev_addr;
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/* see linux/net/ethernet/eth.c to see where I got the following */
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if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
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/* FIXME: fill in the last byte of the dest ipaddr here to
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* better comply with RFC1051 in "noarp" mode.
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*/
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pkt->hard.dest = 0;
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return hdr_size;
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}
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/* otherwise, just fill it in and go! */
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pkt->hard.dest = daddr;
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return hdr_size; /* success */
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}
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static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
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int bufnum)
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{
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struct arcnet_local *lp = netdev_priv(dev);
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struct arc_hardware *hard = &pkt->hard;
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int ofs;
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/* hard header is not included in packet length */
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length -= ARC_HDR_SIZE;
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/* And neither is the cookie field */
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length -= sizeof(int);
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arc_printk(D_DURING, dev, "prepare_tx: txbufs=%d/%d/%d\n",
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lp->next_tx, lp->cur_tx, bufnum);
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arc_printk(D_PROTO, dev, "Sending for cap packet %x.\n",
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*((int *)&pkt->soft.cap.cookie[0]));
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if (length > XMTU) {
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/* should never happen! other people already check for this. */
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arc_printk(D_NORMAL, dev, "Bug! prepare_tx with size %d (> %d)\n",
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length, XMTU);
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length = XMTU;
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}
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if (length > MinTU) {
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hard->offset[0] = 0;
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hard->offset[1] = ofs = 512 - length;
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} else if (length > MTU) {
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hard->offset[0] = 0;
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hard->offset[1] = ofs = 512 - length - 3;
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} else {
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hard->offset[0] = ofs = 256 - length;
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}
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arc_printk(D_DURING, dev, "prepare_tx: length=%d ofs=%d\n",
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length, ofs);
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/* Copy the arcnet-header + the protocol byte down: */
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lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
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lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft.cap.proto,
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sizeof(pkt->soft.cap.proto));
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/* Skip the extra integer we have written into it as a cookie
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* but write the rest of the message:
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*/
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lp->hw.copy_to_card(dev, bufnum, ofs + 1,
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((unsigned char *)&pkt->soft.cap.mes), length - 1);
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lp->lastload_dest = hard->dest;
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return 1; /* done */
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}
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static int ack_tx(struct net_device *dev, int acked)
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{
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struct arcnet_local *lp = netdev_priv(dev);
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struct sk_buff *ackskb;
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struct archdr *ackpkt;
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int length = sizeof(struct arc_cap);
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arc_printk(D_DURING, dev, "capmode: ack_tx: protocol: %x: result: %d\n",
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lp->outgoing.skb->protocol, acked);
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if (BUGLVL(D_SKB))
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arcnet_dump_skb(dev, lp->outgoing.skb, "ack_tx");
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/* Now alloc a skb to send back up through the layers: */
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ackskb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
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if (!ackskb)
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goto free_outskb;
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skb_put(ackskb, length + ARC_HDR_SIZE);
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ackskb->dev = dev;
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skb_reset_mac_header(ackskb);
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ackpkt = (struct archdr *)skb_mac_header(ackskb);
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/* skb_pull(ackskb, ARC_HDR_SIZE); */
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skb_copy_from_linear_data(lp->outgoing.skb, ackpkt,
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ARC_HDR_SIZE + sizeof(struct arc_cap));
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ackpkt->soft.cap.proto = 0; /* using protocol 0 for acknowledge */
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ackpkt->soft.cap.mes.ack = acked;
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arc_printk(D_PROTO, dev, "Acknowledge for cap packet %x.\n",
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*((int *)&ackpkt->soft.cap.cookie[0]));
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ackskb->protocol = cpu_to_be16(ETH_P_ARCNET);
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if (BUGLVL(D_SKB))
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arcnet_dump_skb(dev, ackskb, "ack_tx_recv");
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netif_rx(ackskb);
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free_outskb:
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dev_kfree_skb_irq(lp->outgoing.skb);
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lp->outgoing.proto = NULL;
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/* We are always finished when in this protocol */
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return 0;
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}
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static struct ArcProto capmode_proto = {
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.suffix = 'r',
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.mtu = XMTU,
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.rx = rx,
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.build_header = build_header,
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.prepare_tx = prepare_tx,
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.ack_tx = ack_tx
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};
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static int __init capmode_module_init(void)
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{
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int count;
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pr_info("cap mode (`c') encapsulation support loaded\n");
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for (count = 1; count <= 8; count++)
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if (arc_proto_map[count] == arc_proto_default)
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arc_proto_map[count] = &capmode_proto;
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/* for cap mode, we only set the bcast proto if there's no better one */
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if (arc_bcast_proto == arc_proto_default)
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arc_bcast_proto = &capmode_proto;
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arc_proto_default = &capmode_proto;
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arc_raw_proto = &capmode_proto;
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return 0;
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}
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static void __exit capmode_module_exit(void)
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{
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arcnet_unregister_proto(&capmode_proto);
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}
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module_init(capmode_module_init);
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module_exit(capmode_module_exit);
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MODULE_LICENSE("GPL");
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