Problem with CMEM on OMAP3

Michael K.

Hallo,

I'm using a Beagleboard and try to share memory with the cmem APIs.

My ARM side code is:

CMEM_init();
myParams.type = CMEM_POOL;
myParams.flags = CMEM_NONCACHED;
myPool_ID = CMEM_getPool(BufferSize);
myPoolAddr_virt = (Uint8*) CMEM_allocPool(myPool_ID, &myParams);

*myPoolAddr_virt=x;
printf("%x\n", myPoolAddr_virt);
printf("%d\n", *myPoolAddr_virt);
myPoolAddr_phys = (Uint8*) CMEM_getPhys(myPoolAddr_virt);
printf("%x\n", myPoolAddr_phys);

status=PROC_setup (NULL) ;
if (DSP_SUCCEEDED (status)) {
status = PROC_attach (processorId, NULL) ;
}
if (DSP_SUCCEEDED (status)) {
status = PROC_load (processorId, dspExecutable,numArgs, args) ;
}
if (DSP_SUCCEEDED (status)) {
status = PROC_start (processorId) ;
}

sleep(3);

printf("%d\n", *myPoolAddr_virt);
printf("%d\n", *myPoolAddr_phys);

And DSP Side:

int x=321;
Uint8 * myPoolAddr_phys;

myPoolAddr_phys = (Uint8 *) 0x8d800000;
*myPoolAddr_phys=x;

I want test with this easy example to learn how to use cmem but on ARM side I get the same value of x before and after the DSP.

What I'm doing wrong?

best regards

Michael

over 14 years ago

0 Chris Ring over 14 years ago

TI__Genius 17205 points

Assuming the DSP loaded, booted and ran... this is probably a DSP-side cache issue. The DSP-side cache settings are described a bit here:

http://processors.wiki.ti.com/index.php/Enabling_64x%2B_Cache

When the DSP writes to an external memory address, if that memory is cached, you'll need to issue a cache writeback call. Are you using the DSP/BIOS OS on the DSP? If so, this cache writeback is typically done via DSP/BIOS's BCACHE APIs.

Chris

0 Michael K. over 14 years ago in reply to Chris Ring

Prodigy 40 points

Hallo Chris,

yes, the DSP loaded, booted and ran. Now I took the Message Example from DSPLink and put my lines of code in it to confirm, that I initialize the dsp correct.

All is compiling with no errors, the Messages from the Example are transfered but my number on the virtual address is the same.

Now I have read in the DSP/BIOS API Guide about the BCACHE APIs and build in the bcache_wb api on dsp-side but it's the same :(

Do you have another idea?

best regards

Michael