Adding more it,
I have removed the shared memory kernel driver dependency just to narrow down
the problem area and I have written a small piece of code in user space. A
writer & a reader application which access the shared memory and I got the same
behavior as with the shared memory kernel driver. Interestingly, my user space
application work fine on P1022DS but not on P1022RDK however both using the
same CPU modules.
When I write a simple string on shared memory from Core 1 it is read at Core 0
properly
When I write a simple string on shared memory from Core 0 it is not read at
Core 1.
With this test now I am sure the problem lies in the kernel itself. Any
pointers to look for the troubled area ?
My application code is (error checking and other code is omitted)
#define SHM_BASE 0x1C000000
#define SHM_SIZE 0x400000 // 4 MB of Shared Memory
#define PAGE_SIZE (4*1024)
fd = open(device, O_RDWR);
shm = malloc(SHM_SIZE + (PAGE_SIZE - 1));
if ( (unsigned long) shm % PAGE_SIZE) {
shm += PAGE_SIZE - ((unsigned long)shm % PAGE_SIZE);
}
shm = mmap(shm, SHM_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED | MAP_FIXED, fd,
SHM_BASE);
......
...... write some string at shm.
My memory partitioning for both systems is
Core Base Address Size
Core 0 0x0000,0000 0x1000,0000
Core 1 0x1000,0000 0x0C00,0000
Shared Memory 0x1C00,0000 0x0400,0000
Regards,
Farrukh Arshad.
Mentor Graphics Pakistan
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