Hello, Dan!
> That should work, I do this quite regularly. What actually fails,
> the mmap() or your access to the mapped region?
mmap fails with EINVAL.
> There is what I do:
>
> mem_addr = (u_char *)mmap(NULL, FLASH_MEM_SIZE,
> (PROT_READ | PROT_WRITE), MAP_SHARED,
> mem_fd, FLASH_MEM_ADDR);
I know that program. FLASH_MEM_SIZE is a small number used only in the
first mmap() to determine the size of the flash. If you make it so big
that (int)(FLASH_MEM_ADDR+FLASH_MEM_SIZE)==0 then mmap() fails.
The test program below works on LinuxPPC (2.2.14 with tweaks for G3) but
fails on RPX/Lite (MontaVista kernel):
mmap at 0xffc00000, size 0x400000 failed: Invalid argument
Regards,
Pavel Roskin
=================================
#include <sys/types.h>
#include <sys/mman.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#define FLASH_MEM_ADDR ((uint)0xffc00000)
#define FLASH_MEM_SIZE ((uint)0x00400000)
int
main(void)
{
int mem_fd, i;
uint mfg, dev;
void* mem_addr = NULL;
if ((mem_fd = open("/dev/mem", O_RDWR)) < 0) {
perror("cannot open /dev/mem");
exit(1);
}
mem_addr = (u_int *)mmap(NULL, FLASH_MEM_SIZE,
(PROT_READ | PROT_WRITE), MAP_SHARED,
mem_fd, FLASH_MEM_ADDR);
if ((int)mem_addr < 0) {
fprintf(stderr, "mmap at 0x%x, size 0x%x failed: %s\n",
FLASH_MEM_ADDR, FLASH_MEM_SIZE, strerror(errno));
exit(1);
}
}
=================================
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