Other Parts Discussed in Thread: DA8XX
Software versions: DSPLink 1.65 on TimeSys Linux (Linux omapl137_evm 2.6.29-ts-armv5l #1 PREEMPT Mon Oct 19 12:24:38 EDT 2009 armv5tejl GNU/Linux)
I have an application A that sets up DSPLink, creates a pool, allocates a buffer and starts a DSP executable. I have an application B which is passed the shared memory pool which is passed the memory address of the pool. When I try to access that memory from app B, it crashes with a segmentation fault. App A is, of course, fine.
I believe the reason app B seg faults is because it does not have access to the dsp shared region in it's memory map. However, when I try to add it with mmap (using the method below), I get an error from mmap saying "No such device." Any hints as to how to access the shared memory region allocated in app A?
int Application::mapFlagAddress() {
int Application::mapFlagAddress() {
int result = 0;
int pa_offset;
int pageSize = sysconf(_SC_PAGE_SIZE);
unsigned char *flag_mem; // keep track of this?
if(flag_fd = open("/dev/mem", O_RDWR) < 0) {
perror("Application::mapFlagAddress() can not open /dev/mem");
result = -1;
}
// I think this buffer is too big.
else if((flag_mem = (unsigned char*)malloc(controlCom->flagBufferSize + pageSize)) == NULL) {
perror("Application::mapFlagAddress() could not allocate memory to map");
result = -1;
}
else {
printf("flag_mem 0: %x\n", (unsigned int)flag_mem);
if((unsigned long)flag_mem % pageSize) {
flag_mem += pageSize - ((unsigned long)flag_mem % pageSize);
}
// make sure this is right.
if(controlCom->flagBufferSize % pageSize) {
controlCom->flagBufferSize = (controlCom->flagBufferSize / pageSize) + pageSize;
}
printf("flag_mem 1: %x\n", flag_mem);
}
// make sure this is right.
if(controlCom->flagBufferSize % pageSize) {
controlCom->flagBufferSize = (controlCom->flagBufferSize / pageSize) + pageSize;
}
printf("flag_mem 1: %x\n", flag_mem);
printf("flagBufferSize: %x\n", controlCom->flagBufferSize);
// calculate the memory offset, must be page aligned.
pa_offset = (int)(controlCom->armFlagAddress) & ~(sysconf(_SC_PAGE_SIZE) -1);
flag_mem = (unsigned char *)mmap(
(caddr_t)flag_mem,
controlCom->flagBufferSize,
PROT_READ | PROT_WRITE,
MAP_SHARED,
flag_fd,
pa_offset
);
if((long)flag_mem < 0) {
perror("Application::mapFlagAddress() could not map memory");
result = -1;
}
else {
flag_mem = flag_mem + ((int)controlCom->armFlagAddress - pa_offset);
flagAddress = (Flags *)flag_mem;
}
}
return result;
}
Thanks,
Chris
Chris
