mmap64/open64/pread etc on 440GX

[Neil Wilson]

Hi,

I am trying to write a command line utility for our dev board
(440GX,2.6.9 kernel) in order to provide support for our hardware
engineers.  As a test I am trying to dump the first few bytes of the
U-boot header.

I though that this would work but using /dev/mem gives me a bad address
error on the pread64, using /dev/kmem only reads back 0 bytes.  Is there
something blindingly obvious that I am missing for using 36bit addresses
? I believe the address is correct as I can see the boot code from
within the kernel. Thanks.

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>

unsigned char buf[10240];

int main(int argc,char **argv)
{
	unsigned long long memAddr=0x00000001fff80000ULL;
	int x;
	int fd;
	int readSize;
	int pageSize;
	
	pageSize=sysconf(_SC_PAGESIZE);
	
	fd=open64("/dev/mem", O_RDWR);
	if(fd==-1)
	{
		perror("open64");
		return 0;
	}
	
	readSize=pread64(fd,(void*)buf,pageSize,memAddr);
	
	if(readSize != pageSize)
	{
		perror("pread64 ");
		printf("only read %d of %d requested bytes\n", readSize,
pageSize);
	}
	
	close(fd);
	
	// show some of it
	if(readSize>0)
	{
		for(x=0;x<25;x++)
		{
			printf("%02x(%c)
",buf[x],isprint(buf[x])?buf[x]:'.');
		}
		printf("\n");
	}
}

Neil

--
Neil Wilson
Airspan Communications Ltd.
Cambridge House, Oxford Road,
Uxbridge, Middx, UB8 1UN, UK.
Tel: +44(0)1895-467265

neilwilson at airspan.com
www.airspan.com