vme_user causes system hang/freeze

[Martyn Welch]

Hi Steven,

I have run this test up on a pair of boards I have access to. I had to declare
the loop variable, but other than that it seems to be running fine here (I'm
testing this on the head of the staging tree[1]):

root at ge-xvb601:~/vme_test# uname -r
3.9.0
root at ge-xvb601:~/vme_test# gcc -o test_extended test_extended.c
root at ge-xvb601:~/vme_test# ./test_extended > test.txt
root at ge-xvb601:~/vme_test# wc -l test.txt
900 test.txt
root at ge-xvb601:~/vme_test# tail test.txt
0038: ff ff df ff df ff ff ff

0000: ff ff ff fb ff f5 ff ff
0008: ff ff ff ff 7f ff ff ff
0010: ff ff df df be fb ff fe
0018: ff f7 ff f7 7f ea ff ff
0020: ff ef ff ff d8 ee ff ff
0028: ff ff ff ff 7e f7 ff f7
0030: ff ff 7b 6e 5d df ff ff
0038: ff ff df ff df ff ff ff
root at ge-xvb601:~/vme_test#

Which version of kernel are you running this on?

Martyn


[1] git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git

On 02/05/13 09:33, De Roo, Steven wrote:
> Dear all,
> 
> I've been trying to access the VME-bus using a Xembedded XVME-6300 board 
> (with TSI-148 chipset) and the vme_user module from Martyn, with success.
> (Thanks to Martyn for an easy demo program).
> 
> I've modified the code (see below) to...
> - use A_32/D_32
> - use 0x8BB00000 as base address
> - read data at an offset 0x8400 from this address
> - do a read of 6400 bytes instead of 512 bytes
> This seems to be working perfect (another VME-card writes a recognizable 
> pattern at the above address, and I can see it using the printf-statements).
> 
> HOWEVER:
> When I do this read in a loop (eg. 100 times), 
> then my whole system freezes/hangs after about 50 times,
> and I have to power off/power on the machine...
> 
> Does anybody have an idea what's going wrong ?
> Can I activate something to find out the problem ?
> 
> Kind regards,
> Steven De Roo
> 
> --------------------------------------------------------------------------------
> 
> #define _XOPEN_SOURCE 500
> #define u32 unsigned int // Needed to add this line
> #include <linux/types.h> // Needed to add this line
> #include <stdio.h>
> #include <stdlib.h>
> #include <sys/ioctl.h>
> #include <sys/types.h>
> #include <sys/stat.h>
> #include <fcntl.h>
> #include <unistd.h>
> #include "vme_user.h"
> 
> int main(int argc, char *argv[])
> {
>         int fd;
>         int i;
>         int retval;
>         unsigned char data[6400];
> 
>         struct vme_master master;
> 
>         fd = open("/dev/bus/vme/m0", O_RDONLY);
>         if (fd == -1) {
>                 perror("ERROR: Opening window device file");
>                 return 1;
>         }
> 
>         master.enable   = 1;
>         master.vme_addr = 0x8BB00000; 
>         master.size     = 0x10000;
>         master.aspace   = 4; // VME_A32
>         master.cycle    = 0x2000 | 0x8000; // user/data access
>         master.dwidth   = 4; // VME_D32
> 
>         retval = ioctl(fd, VME_SET_MASTER, &master);
>         if (retval != 0) {
>                 printf("retval=%d\n", retval);
>                 perror("ERROR: Failed to configure window");
>                 return 1;
>         }
>         for (i=0; i<sizeof(data); i++) {
>                 data[i] = 0;
>         }
> 
>         for (loop=0; loop<100; loop++)
>         { 
>                 retval = pread(fd, data, sizeof(data), 0x8400); 
>                 if (retval < sizeof(data)) {
>                         printf("WARNING: Only read %d bytes", retval);
>                 }
>         
>         	    // Print first 64 bytes
>                 for(i=0; i<8*8; i++) {
>                         if (i % 8 == 0) {
>                                 printf("\n""%4.4x: ", i);
>                         }
>                         printf("%2.2x ", data[i]);
>                 }
>                 printf("\n");
>         }
> 
>         close(fd);
> 
>         return 0;
> }
> 


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