freebsd-dev/sys/i386/boot/netboot/ether.c
Jordan K. Hubbard 00ed485bc4 Really provide support for 3COM cards now.
Submitted by:	wpaul
1994-12-31 17:16:50 +00:00

644 lines
21 KiB
C

/**************************************************************************
NETBOOT - BOOTP/TFTP Bootstrap Program
Author: Martin Renters
Date: May/94
This code is based heavily on David Greenman's if_ed.c driver
Copyright (C) 1993-1994, David Greenman, Martin Renters.
This software may be used, modified, copied, distributed, and sold, in
both source and binary form provided that the above copyright and these
terms are retained. Under no circumstances are the authors responsible for
the proper functioning of this software, nor do the authors assume any
responsibility for damages incurred with its use.
3c503 support added by Bill Paul (wpaul@ctr.columbia.edu) on 11/15/94
SMC8416 support added by Bill Paul (wpaul@ctr.columbia.edu) on 12/25/94
**************************************************************************/
#include "netboot.h"
#include "ether.h"
extern short aui;
unsigned short eth_nic_base;
unsigned short eth_asic_base;
unsigned char eth_tx_start;
unsigned char eth_laar;
unsigned char eth_flags;
unsigned char eth_vendor;
unsigned char eth_memsize;
unsigned char *eth_bmem;
unsigned char *eth_rmem;
unsigned char *eth_node_addr;
/**************************************************************************
The following two variables are used externally
**************************************************************************/
char packet[ETH_MAX_PACKET];
int packetlen;
/**************************************************************************
ETH_PROBE - Look for an adapter
**************************************************************************/
eth_probe()
{
int i;
struct wd_board *brd;
char *name;
unsigned short chksum;
unsigned char c;
eth_vendor = VENDOR_NONE;
#ifdef INCLUDE_WD
/******************************************************************
Search for WD/SMC cards
******************************************************************/
for (eth_asic_base = WD_LOW_BASE; eth_asic_base <= WD_HIGH_BASE;
eth_asic_base += 0x20) {
chksum = 0;
for (i=8; i<16; i++)
chksum += inb(i+eth_asic_base);
if ((chksum & 0x00FF) == 0x00FF)
break;
}
if (eth_asic_base <= WD_HIGH_BASE) { /* We've found a board */
eth_vendor = VENDOR_WD;
eth_nic_base = eth_asic_base + WD_NIC_ADDR;
c = inb(eth_asic_base+WD_BID); /* Get board id */
for (brd = wd_boards; brd->name; brd++)
if (brd->id == c) break;
if (!brd->name) {
printf("\r\nUnknown Ethernet type %x\r\n", c);
return(0); /* Unknown type */
}
eth_flags = brd->flags;
eth_memsize = brd->memsize;
eth_tx_start = 0;
if ((c == TYPE_WD8013EP) &&
(inb(eth_asic_base + WD_ICR) & WD_ICR_16BIT)) {
eth_flags = FLAG_16BIT;
eth_memsize = MEM_16384;
}
if ((c & WD_SOFTCONFIG) && (!(eth_flags & FLAG_790))) {
eth_bmem = (char *)(0x80000 |
((inb(eth_asic_base + WD_MSR) & 0x3F) << 13));
} else
eth_bmem = (char *)WD_DEFAULT_MEM;
if (brd->id == TYPE_SMC8216T || brd->id == TYPE_SMC8216C) {
(unsigned int) *(eth_bmem + 8192) = (unsigned int)0;
if ((unsigned int) *(eth_bmem + 8192)) {
brd += 2;
eth_memsize = brd->memsize;
}
}
outb(eth_asic_base + WD_MSR, 0x80); /* Reset */
printf("\r\n%s base 0x%x, memory 0x%X, addr ",
brd->name, eth_asic_base, eth_bmem);
for (i=0; i<6; i++) {
printf("%b",(int)(arptable[ARP_CLIENT].node[i] =
inb(i+eth_asic_base+WD_LAR)));
if (i < 5) printf (":");
}
if (eth_flags & FLAG_790) {
outb(eth_asic_base+WD_MSR, WD_MSR_MENB);
outb(eth_asic_base+0x04, (inb(eth_asic_base+0x04) |
0x80));
outb(eth_asic_base+0x0B,
(((unsigned)eth_bmem >> 13) & 0x0F) |
(((unsigned)eth_bmem >> 11) & 0x40) |
(inb(eth_asic_base+0x0B) & 0xB0));
outb(eth_asic_base+0x04, (inb(eth_asic_base+0x04) &
~0x80));
} else {
outb(eth_asic_base+WD_MSR,
(((unsigned)eth_bmem >> 13) & 0x3F) | 0x40);
}
if (eth_flags & FLAG_16BIT) {
if (eth_flags & FLAG_790) {
eth_laar = inb(eth_asic_base + WD_LAAR);
outb(eth_asic_base + WD_LAAR, WD_LAAR_M16EN);
inb(0x84);
} else {
outb(eth_asic_base + WD_LAAR, (eth_laar =
WD_LAAR_M16EN | WD_LAAR_L16EN | 1));
}
}
printf("\r\n");
}
#endif
#ifdef INCLUDE_3COM
/******************************************************************
Search for 3Com 3c503 if no WD/SMC cards
******************************************************************/
if (eth_vendor == VENDOR_NONE) {
eth_asic_base = _3COM_BASE + _3COM_ASIC_OFFSET;
eth_nic_base = _3COM_BASE;
eth_vendor = VENDOR_3COM;
/*
* Note that we use the same settings for both 8 and 16 bit cards:
* both have an 8K bank of memory at page 1 while only the 16 bit
* cards have a bank at page 0.
*/
eth_memsize = MEM_16384;
eth_tx_start = 32;
/* Check our base address */
switch(inb(eth_asic_base + _3COM_BCFR)) {
case _3COM_BCFR_300:
if ((int)eth_nic_base != 0x300)
return(0);
break;
case _3COM_BCFR_310:
if ((int)eth_nic_base != 0x310)
return(0);
break;
case _3COM_BCFR_330:
if ((int)eth_nic_base != 0x330)
return(0);
break;
case _3COM_BCFR_350:
if ((int)eth_nic_base != 0x350)
return(0);
break;
case _3COM_BCFR_250:
if ((int)eth_nic_base != 0x250)
return(0);
break;
case _3COM_BCFR_280:
if ((int)eth_nic_base != 0x280)
return(0);
break;
case _3COM_BCFR_2A0:
if ((int)eth_nic_base != 0x2a0)
return(0);
break;
case _3COM_BCFR_2E0:
if ((int)eth_nic_base != 0x2e0)
return(0);
break;
default:
return (0);
}
/* Now get the shared memory address */
switch (inb(eth_asic_base + _3COM_PCFR)) {
case _3COM_PCFR_DC000:
eth_bmem = (char *)0xdc000;
break;
case _3COM_PCFR_D8000:
eth_bmem = (char *)0xd8000;
break;
case _3COM_PCFR_CC000:
eth_bmem = (char *)0xcc000;
break;
case _3COM_PCFR_C8000:
eth_bmem = (char *)0xc8000;
break;
default:
return (0);
}
/* Need this to make eth_poll() happy. */
eth_rmem = eth_bmem - 0x2000;
/* Reset NIC and ASIC */
outb (eth_asic_base + _3COM_CR , _3COM_CR_RST | _3COM_CR_XSEL);
outb (eth_asic_base + _3COM_CR , _3COM_CR_XSEL);
/* Get our ethernet address */
outb(eth_asic_base + _3COM_CR, _3COM_CR_EALO | _3COM_CR_XSEL);
printf("\r\n3Com 3c503 base 0x%x, memory 0x%X addr ",
eth_nic_base, eth_bmem);
for (i=0; i<6; i++) {
printf("%b",(int)(arptable[ARP_CLIENT].node[i] =
inb(eth_nic_base+i)));
if (i < 5) printf (":");
}
outb(eth_asic_base + _3COM_CR, _3COM_CR_XSEL);
/*
* Initialize GA configuration register. Set bank and enable shared
* mem. We always use bank 1.
*/
outb(eth_asic_base + _3COM_GACFR, _3COM_GACFR_RSEL |
_3COM_GACFR_MBS0);
outb(eth_asic_base, _3COM_VPTR2, 0xff);
outb(eth_asic_base, _3COM_VPTR1, 0xff);
outb(eth_asic_base, _3COM_VPTR0, 0x00);
/*
* Clear memory and verify that it worked (we use only 8K)
*/
bzero(eth_bmem, 0x2000);
for(i = 0; i < 0x2000; ++i)
if (*((eth_bmem)+i)) {
printf ("Failed to clear 3c503 shared mem.\r\n");
return (0);
}
/*
* Initialize GA page/start/stop registers.
*/
outb(eth_asic_base + _3COM_PSTR, eth_tx_start);
outb(eth_asic_base + _3COM_PSPR, eth_memsize);
printf ("\r\n");
}
#endif
#ifdef INCLUDE_NE
/******************************************************************
Search for NE1000/2000 if no WD/SMC or 3com cards
******************************************************************/
if (eth_vendor == VENDOR_NONE) {
char romdata[16], testbuf[32];
char test[] = "NE1000/2000 memory";
eth_bmem = (char *)0; /* No shared memory */
eth_asic_base = NE_BASE + NE_ASIC_OFFSET;
eth_nic_base = NE_BASE;
eth_vendor = VENDOR_NOVELL;
eth_flags = FLAG_PIO;
eth_memsize = MEM_16384;
eth_tx_start = 32;
c = inb(eth_asic_base + NE_RESET);
outb(eth_asic_base + NE_RESET, c);
inb(0x84);
outb(eth_nic_base + D8390_P0_COMMAND, D8390_COMMAND_STP |
D8390_COMMAND_RD2);
outb(eth_nic_base + D8390_P0_RCR, D8390_RCR_MON);
outb(eth_nic_base + D8390_P0_DCR, D8390_DCR_FT1 | D8390_DCR_LS);
outb(eth_nic_base + D8390_P0_PSTART, MEM_8192);
outb(eth_nic_base + D8390_P0_PSTOP, MEM_16384);
eth_pio_write(test, 8192, sizeof(test));
eth_pio_read(8192, testbuf, sizeof(test));
if (!bcompare(test, testbuf, sizeof(test))) {
eth_flags |= FLAG_16BIT;
eth_memsize = MEM_32768;
eth_tx_start = 64;
outb(eth_nic_base + D8390_P0_DCR, D8390_DCR_WTS |
D8390_DCR_FT1 | D8390_DCR_LS);
outb(eth_nic_base + D8390_P0_PSTART, MEM_16384);
outb(eth_nic_base + D8390_P0_PSTOP, MEM_32768);
eth_pio_write(test, 16384, sizeof(test));
eth_pio_read(16384, testbuf, sizeof(test));
if (!bcompare(testbuf, test, sizeof(test))) return (0);
}
eth_pio_read(0, romdata, 16);
printf("\r\nNE1000/NE2000 base 0x%x, addr ", eth_nic_base);
for (i=0; i<6; i++) {
printf("%b",(int)(arptable[ARP_CLIENT].node[i] = romdata[i
+ ((eth_flags & FLAG_16BIT) ? i : 0)]));
if (i < 5) printf (":");
}
printf("\r\n");
}
#endif
if (eth_vendor == VENDOR_NONE) return(0);
if (eth_vendor != VENDOR_3COM) eth_rmem = eth_bmem;
eth_node_addr = arptable[ARP_CLIENT].node;
eth_reset();
return(eth_vendor);
}
/**************************************************************************
ETH_RESET - Reset adapter
**************************************************************************/
eth_reset()
{
int i;
if (eth_flags & FLAG_790)
outb(eth_nic_base+D8390_P0_COMMAND,
D8390_COMMAND_PS0 | D8390_COMMAND_STP);
else
outb(eth_nic_base+D8390_P0_COMMAND,
D8390_COMMAND_PS0 | D8390_COMMAND_RD2 |
D8390_COMMAND_STP);
if (eth_flags & FLAG_16BIT)
outb(eth_nic_base+D8390_P0_DCR, 0x49);
else
outb(eth_nic_base+D8390_P0_DCR, 0x48);
outb(eth_nic_base+D8390_P0_RBCR0, 0);
outb(eth_nic_base+D8390_P0_RBCR1, 0);
outb(eth_nic_base+D8390_P0_RCR, 4); /* allow broadcast frames */
outb(eth_nic_base+D8390_P0_TCR, 2);
outb(eth_nic_base+D8390_P0_TPSR, eth_tx_start);
outb(eth_nic_base+D8390_P0_PSTART, eth_tx_start + D8390_TXBUF_SIZE);
if (eth_flags & FLAG_790) outb(eth_nic_base + 0x09, 0);
outb(eth_nic_base+D8390_P0_PSTOP, eth_memsize);
outb(eth_nic_base+D8390_P0_BOUND, eth_tx_start + D8390_TXBUF_SIZE);
outb(eth_nic_base+D8390_P0_ISR, 0xFF);
outb(eth_nic_base+D8390_P0_IMR, 0);
if (eth_flags & FLAG_790)
outb(eth_nic_base+D8390_P0_COMMAND, D8390_COMMAND_PS1 |
D8390_COMMAND_STP);
else
outb(eth_nic_base+D8390_P0_COMMAND, D8390_COMMAND_PS1 |
D8390_COMMAND_RD2 | D8390_COMMAND_STP);
for (i=0; i<6; i++)
outb(eth_nic_base+D8390_P1_PAR0+i, eth_node_addr[i]);
for (i=0; i<6; i++)
outb(eth_nic_base+D8390_P1_MAR0+i, 0xFF);
outb(eth_nic_base+D8390_P1_CURR, eth_tx_start + D8390_TXBUF_SIZE+1);
if (eth_flags & FLAG_790)
outb(eth_nic_base+D8390_P0_COMMAND, D8390_COMMAND_PS0 |
D8390_COMMAND_STA);
else
outb(eth_nic_base+D8390_P0_COMMAND, D8390_COMMAND_PS0 |
D8390_COMMAND_RD2 | D8390_COMMAND_STA);
outb(eth_nic_base+D8390_P0_ISR, 0xFF);
outb(eth_nic_base+D8390_P0_TCR, 0);
#ifdef INCLUDE_3COM
if (eth_vendor == VENDOR_3COM) {
/*
* No way to tell whether or not we're supposed to use
* the 3Com's transceiver unless the user tells us.
* 'aui' should have some compile time default value
* which can be changed from the command menu.
*/
if (aui)
outb(eth_asic_base + _3COM_CR, 0);
else
outb(eth_asic_base + _3COM_CR, _3COM_CR_XSEL);
}
#endif
return(1);
}
/**************************************************************************
ETH_TRANSMIT - Transmit a frame
**************************************************************************/
eth_transmit(d,t,s,p)
char *d; /* Destination */
unsigned short t; /* Type */
unsigned short s; /* size */
char *p; /* Packet */
{
unsigned char c;
#ifdef INCLUDE_3COM
if (eth_vendor == VENDOR_3COM) {
bcopy(d, eth_bmem, 6); /* dst */
bcopy(eth_node_addr, eth_bmem+6, ETHER_ADDR_SIZE); /* src */
*(eth_bmem+12) = t>>8; /* type */
*(eth_bmem+13) = t;
bcopy(p, eth_bmem+14, s);
s += 14;
while (s < ETH_MIN_PACKET) *(eth_bmem+(s++)) = 0;
}
#endif
#ifdef INCLUDE_WD
if (eth_vendor == VENDOR_WD) { /* Memory interface */
if (eth_flags & FLAG_16BIT) {
outb(eth_asic_base + WD_LAAR, eth_laar | WD_LAAR_M16EN);
inb(0x84);
}
if (eth_flags & FLAG_790) {
outb(eth_asic_base + WD_MSR, WD_MSR_MENB);
inb(0x84);
}
inb(0x84);
bcopy(d, eth_bmem, 6); /* dst */
bcopy(eth_node_addr, eth_bmem+6, ETHER_ADDR_SIZE); /* src */
*(eth_bmem+12) = t>>8; /* type */
*(eth_bmem+13) = t;
bcopy(p, eth_bmem+14, s);
s += 14;
while (s < ETH_MIN_PACKET) *(eth_bmem+(s++)) = 0;
if (eth_flags & FLAG_790) {
outb(eth_asic_base + WD_MSR, 0);
inb(0x84);
}
if (eth_flags & FLAG_16BIT) {
outb(eth_asic_base + WD_LAAR, eth_laar & ~WD_LAAR_M16EN);
inb(0x84);
}
}
#endif
#ifdef INCLUDE_NE
if (eth_vendor == VENDOR_NOVELL) { /* Programmed I/O */
unsigned short type;
type = (t >> 8) | (t << 8);
eth_pio_write(d, eth_tx_start<<8, 6);
eth_pio_write(eth_node_addr, (eth_tx_start<<8)+6, 6);
eth_pio_write(&type, (eth_tx_start<<8)+12, 2);
eth_pio_write(p, (eth_tx_start<<8)+14, s);
s += 14;
if (s < ETH_MIN_PACKET) s = ETH_MIN_PACKET;
}
#endif
twiddle();
if (eth_flags & FLAG_790)
outb(eth_nic_base+D8390_P0_COMMAND, D8390_COMMAND_PS0 |
D8390_COMMAND_STA);
else
outb(eth_nic_base+D8390_P0_COMMAND, D8390_COMMAND_PS0 |
D8390_COMMAND_RD2 | D8390_COMMAND_STA);
outb(eth_nic_base+D8390_P0_TPSR, eth_tx_start);
outb(eth_nic_base+D8390_P0_TBCR0, s);
outb(eth_nic_base+D8390_P0_TBCR1, s>>8);
if (eth_flags & FLAG_790)
outb(eth_nic_base+D8390_P0_COMMAND, D8390_COMMAND_PS0 |
D8390_COMMAND_TXP | D8390_COMMAND_STA);
else
outb(eth_nic_base+D8390_P0_COMMAND, D8390_COMMAND_PS0 |
D8390_COMMAND_TXP | D8390_COMMAND_RD2 |
D8390_COMMAND_STA);
return(0);
}
/**************************************************************************
ETH_POLL - Wait for a frame
**************************************************************************/
eth_poll()
{
int ret = 0;
unsigned short type = 0;
unsigned char bound,curr,rstat;
unsigned short len;
unsigned short pktoff;
unsigned char *p;
struct ringbuffer pkthdr;
rstat = inb(eth_nic_base+D8390_P0_RSR);
if (rstat & D8390_RSTAT_OVER) {
eth_reset();
return(0);
}
if (!(rstat & D8390_RSTAT_PRX)) return(0);
bound = inb(eth_nic_base+D8390_P0_BOUND)+1;
if (bound == eth_memsize) bound = eth_tx_start + D8390_TXBUF_SIZE;
outb(eth_nic_base+D8390_P0_COMMAND, D8390_COMMAND_PS1);
curr = inb(eth_nic_base+D8390_P1_CURR);
outb(eth_nic_base+D8390_P0_COMMAND, D8390_COMMAND_PS0);
if (curr == eth_memsize) curr=eth_tx_start + D8390_TXBUF_SIZE;
if (curr == bound) return(0);
if (eth_vendor == VENDOR_WD) {
if (eth_flags & FLAG_16BIT) {
outb(eth_asic_base + WD_LAAR, eth_laar | WD_LAAR_M16EN);
inb(0x84);
}
if (eth_flags & FLAG_790) {
outb(eth_asic_base + WD_MSR, WD_MSR_MENB);
inb(0x84);
}
inb(0x84);
}
pktoff = (bound << 8);
if (eth_flags & FLAG_PIO)
eth_pio_read(pktoff, &pkthdr, 4);
else
bcopy(eth_rmem + pktoff, &pkthdr, 4);
len = pkthdr.len - 4; /* sub CRC */
pktoff += 4;
if (len > 1514) len = 1514;
bound = pkthdr.bound; /* New bound ptr */
if ( (pkthdr.status & D8390_RSTAT_PRX) && (len > 14) && (len < 1518)) {
p = packet;
packetlen = len;
len = (eth_memsize << 8) - pktoff;
if (packetlen > len) { /* We have a wrap-around */
if (eth_flags & FLAG_PIO)
eth_pio_read(pktoff, p, len);
else
bcopy(eth_rmem + pktoff, p, len);
pktoff = (eth_tx_start + D8390_TXBUF_SIZE) << 8;
p += len;
packetlen -= len;
}
if (eth_flags & FLAG_PIO)
eth_pio_read(pktoff, p, packetlen);
else
bcopy(eth_rmem + pktoff, p, packetlen);
type = (packet[12]<<8) | packet[13];
ret = 1;
}
if (eth_vendor == VENDOR_WD) {
if (eth_flags & FLAG_790) {
outb(eth_asic_base + WD_MSR, 0);
inb(0x84);
}
if (eth_flags & FLAG_16BIT) {
outb(eth_asic_base + WD_LAAR, eth_laar &
~WD_LAAR_M16EN);
inb(0x84);
}
inb(0x84);
}
if (bound == (eth_tx_start + D8390_TXBUF_SIZE))
bound = eth_memsize;
outb(eth_nic_base+D8390_P0_BOUND, bound-1);
if (ret && (type == ARP)) {
struct arprequest *arpreq;
unsigned long reqip;
arpreq = (struct arprequest *)&packet[ETHER_HDR_SIZE];
convert_ipaddr(&reqip, arpreq->tipaddr);
if ((ntohs(arpreq->opcode) == ARP_REQUEST) &&
(reqip == arptable[ARP_CLIENT].ipaddr)) {
arpreq->opcode = htons(ARP_REPLY);
bcopy(arpreq->sipaddr, arpreq->tipaddr, 4);
bcopy(arpreq->shwaddr, arpreq->thwaddr, 6);
bcopy(arptable[ARP_CLIENT].node, arpreq->shwaddr, 6);
convert_ipaddr(arpreq->sipaddr, &reqip);
eth_transmit(arpreq->thwaddr, ARP, sizeof(struct arprequest),
arpreq);
return(0);
}
}
return(ret);
}
#ifdef INCLUDE_NE
/**************************************************************************
NE1000/NE2000 Support Routines
**************************************************************************/
static inline unsigned short inw(unsigned short a)
{
unsigned short d;
asm volatile( "inw %1, %0" : "=a" (d) : "d" (a));
return d;
}
static inline void outw(unsigned short a, unsigned short d)
{
asm volatile( "outw %0, %1" : : "a" (d), "d" (a));
}
/**************************************************************************
ETH_PIO_READ - Read a frame via Programmed I/O
**************************************************************************/
eth_pio_read(src, dst, cnt, init)
unsigned short src;
unsigned char *dst;
unsigned short cnt;
int init;
{
if (cnt & 1) cnt++;
outb(eth_nic_base + D8390_P0_COMMAND, D8390_COMMAND_RD2 |
D8390_COMMAND_STA);
outb(eth_nic_base + D8390_P0_RBCR0, cnt);
outb(eth_nic_base + D8390_P0_RBCR1, cnt>>8);
outb(eth_nic_base + D8390_P0_RSAR0, src);
outb(eth_nic_base + D8390_P0_RSAR1, src>>8);
outb(eth_nic_base + D8390_P0_COMMAND, D8390_COMMAND_RD0 |
D8390_COMMAND_STA);
if (eth_flags & FLAG_16BIT) {
while (cnt) {
*((unsigned short *)dst) = inw(eth_asic_base + NE_DATA);
dst += 2;
cnt -= 2;
}
}
else {
while (cnt--)
*(dst++) = inb(eth_asic_base + NE_DATA);
}
}
/**************************************************************************
ETH_PIO_WRITE - Write a frame via Programmed I/O
**************************************************************************/
eth_pio_write(src, dst, cnt, init)
unsigned char *src;
unsigned short dst;
unsigned short cnt;
int init;
{
outb(eth_nic_base + D8390_P0_COMMAND, D8390_COMMAND_RD2 |
D8390_COMMAND_STA);
outb(eth_nic_base + D8390_P0_ISR, D8390_ISR_RDC);
outb(eth_nic_base + D8390_P0_RBCR0, cnt);
outb(eth_nic_base + D8390_P0_RBCR1, cnt>>8);
outb(eth_nic_base + D8390_P0_RSAR0, dst);
outb(eth_nic_base + D8390_P0_RSAR1, dst>>8);
outb(eth_nic_base + D8390_P0_COMMAND, D8390_COMMAND_RD1 |
D8390_COMMAND_STA);
if (eth_flags & FLAG_16BIT) {
if (cnt & 1) cnt++; /* Round up */
while (cnt) {
outw(eth_asic_base + NE_DATA, *((unsigned short *)src));
src += 2;
cnt -= 2;
}
}
else {
while (cnt--)
outb(eth_asic_base + NE_DATA, *(src++));
}
while((inb(eth_nic_base + D8390_P0_ISR) & D8390_ISR_RDC)
!= D8390_ISR_RDC);
}
#else
/**************************************************************************
ETH_PIO_READ - Dummy routine when NE2000 not compiled in
**************************************************************************/
eth_pio_read() {}
#endif