ListMP data not syncing

Jibin Scaria

Other Parts Discussed in Thread: SYSBIOS

Hi,

I am using ListMP to pass data between ARM and DSP in 8148. But the data is not synced always.

Both ARM and DSP are using gate to protect the List

		// get the gate for the ListMP instance
		gate = ListMP_getGate(ghandleListMP);

		// Begin protection against modification of the ListMP.
		key = GateMP_enter(gate);

		while ((elem = ListMP_next(ghandleListMP, elem)) != NULL)
		{

			pListMPNode = (GRG_RINGIO_LISTMP_NODE *)elem;
			
			if(pListMPNode->u32GrgSessionId == u32GrgSessionId)
			{

				if(pListMPNode->eRingIODirection == eRingIODirection)
				{
					
				    System_printf ( "Index = %x",  pListMPNode->u32Index);
				    break;
				}

			}

		}

		// End protection against modification of the ListMP.
		GateMP_leave(gate, key);

The data is correct in few nodes but not in all nodes

Can anybody help me on this?

Thanks

Jibin

over 14 years ago

0 ToddMullanix over 14 years ago

TI__Guru* 96960 points

Jibin,

Do you have cache enabled? If you do, you need to maintain the cache coherency for the application portion of the structure you put on the list. For example, if this is your structure

struct MyListElem {
    ListMP_Elem elem;
    Int sizeofBuffer;
    Char someBuffer[1024];
};

struct MyListElem foo;

Before you add foo onto the ListMP, you must do a

Cache_wbInv(foo, ...); // look at the ti/sysbios/hal/Cache APIs for the exact definition

Similarly, on the receiving side, you should invalid the memory to make sure there is no stale data present.

ListMP maintains cache coherency for the elem portion, but since it does not know the size of the structure, it cannot maintain complete cache coherency. FYI: MessageQ maintains cache coherency on the entire message since it knows the size.

Todd

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ListMP data not syncing