DRV_GMAC_RxFilterHashTableEntrySet Function

TCPIP_MAC_RES DRV_GMAC_RxFilterHashTableEntrySet(DRV_HANDLE hMac, const TCPIP_MAC_ADDR* DestMACAddr); 

• TCPIP_MAC_RES_OK if success

• a TCPIP_MAC_RES error value if failed

This function sets the MAC hash table filtering to allow packets sent to DestMACAddr to be received. It calculates a CRC-32 using polynomial 0x4C11DB7 over the 6 byte MAC address and then, using bits 28:23 of the CRC, will set the appropriate bits in the hash table filter registers ( ETHHT0-ETHHT1). The function will enable/disable the Hash Table receive filter if needed.

• Sets the appropriate bit in the ETHHT0/1 registers to allow packets sent to DestMACAddr to be received and enabled the Hash Table receive filter.

• There is no way to individually remove destination MAC addresses from the hash table since it is possible to have a hash collision and therefore multiple MAC addresses relying on the same hash table bit.

• A workaround is to have the stack store each enabled MAC address and to perform the comparison at run time.

• A call to DRV_GMAC_RxFilterHashTableEntrySet() using a 00-00-00-00-00-00 destination MAC address, which will clear the entire hash table and disable the hash table filter. This will allow the receive of all packets, regardless of their destination

DRV_GMAC_Initialize() should have been called. DRV_GMAC_Open() should have been called to obtain a valid handle.