T1042 memac multicast frame support

[bingcao]

Hi, NXP team

    I am trying to enable support of receive multicast frame by memac. Try set  Hash Table Control Register to 0x13f. But it does not work.
    Can you share the step to enable receive of multicast frame with memac?

[yipingwang]

In order to enable multicast, you need to set COMMAND_CONFIG[PROMIS_EN] = 0 and set up the hash table.

Because the hash address code is 6-bit, you can set up maximum 64 entries in the hash table.

A write to HASHTABLE_CTRL with MCAT_EN=1 will add an entry into the hash table;

A write to HASHTABLE_CTRL with MCAT_EN=0 will remove an entry from the hash table;

Here is an example how the algorithm works

For example
DA (Destination MAC address) = 01:22:33:44:55:66

0x01: 0^0^0^0^0^0^0^1 = 1
0x22: 0^0^1^0^0^0^1^0 = 0
0x33: 0^0^1^1^0^0^1^1 = 0
0x44: 0^1^0^0^0^1^0^0 = 0
0x55: 0^1^0^1^0^1^0^1 = 0
0x66: 0^1^1^0^0^1^1^0 = 0

So it will produce a 6-bit hash address code of 100000.

After adding 100000 to the hash table, any frame with a DA that produces 100000 will be accepted.

[sbansal]

Hello @yipingwang 

I have a connected question regarding hash control register.

We are using T1023 processor and wanting to configure mEMAC4 interface with multiple unicast addresses. In our case, application want to support more than 20 unicast addresses to a given ethernet MAC.

Right now, we have exhausted the 8 dedicated MAC address registers and want to configure subsequent unicast MAC addresses in hash control table, but the packets corresponding to those MACs are not received (seems dropped). So, I have below questions in this regard :

- Does hash ctrl table supports unicast addresses?

- If not, what is the way to support more than 8 unicast MAC addresses on T1023?

Regards,

Sumit