Re: [Gumstix-users] memory corruption with gumstix?

[Lennert B. <bu...@wa...>]

On Mon, Aug 30, 2004 at 03:57:32PM +0200, Lennert Buytenhek wrote:

> > That sounds like general memory corruption. Have you upgraded the
> > flash to fix the ram refresh problem?
> 
> No, I haven't yet.  I was somewhat afraid to brick it and not sure
> if this would solve the problem.
> 
> If you think this is the general ram refresh problem present in the
> older bootloaders, perhaps I can just poke the right value into
> MDCNFG/MDREFR and see if that helps?  Any idea what I should poke
> into there?

OK, MDREFR was 0x039bc0ff, and I just poked 0x039bc018 in there from
userspace (p6-15 of Intel PXA255 Processor Developer's manual.)  I
assume that that should do it, but I'm afraid my root filesystem
might have some subtle corruption by now.. will check it out now.


cheers,
Lennert


#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
                                                                                
int main()
{
        volatile u_int32_t *reg;
        void *x;
        int fd;
                                                                                
        fd = open("/dev/mem", O_RDWR | O_SYNC);
        if (fd < 0) {
                perror("open");
                exit(-1);
        }
                                                                                
        x = mmap(0, 4096, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0x48000000);
        if (x == MAP_FAILED) {
                perror("mmap");
                exit(-1);
        }
                                                                                
        reg = (volatile u_int32_t *)(x + 0x4);
        printf("0x48000004 is %.8x\n", *reg);
        if (*reg == 0x039bc0ff) {
                printf("updating register\n");
                *reg = 0x039bc018;
        }
                                                                                
        return 0;
}