AM6442: DMA for DDRSS

Shine

Genius 13655 points

Part Number: AM6442

Hello Champs,

What type of DMA is used when copying data from DDR to cache?

Thanks
Regards
Shine

over 1 year ago

0 Kallikuppa Sreenivasa over 1 year ago

TI__Guru**** 191669 points

Hello Shine

Thank you for the query.

Help me understand the use case for copying data from DDR to cache. This may not be allowed or possible.

Regards,

Sreenivasa

0 Shine over 1 year ago in reply to Kallikuppa Sreenivasa

TI__Genius 13655 points

Hello Sreenivasa,

Thank you very much for your great support.

When cache hit missing occurs, the core will try to read data from DDR, can the dma be used for the data move from DDR to cache?

Thanks
Regards
Shine

0 Kallikuppa Sreenivasa over 1 year ago in reply to Shine

TI__Guru**** 191669 points

Hello Shine

Thank you.

Shine said:
When cache hit missing occurs, the core will try to read data from DDR, can the dma be used for the data move from DDR to cache?

I am not sure if this is possible since the data is being read by the core.

Let me assign to our expert to get his thoughts.

Regards,

Sreenivasa

+1 Pekka Varis over 1 year ago in reply to Kallikuppa Sreenivasa

TI__Mastermind 27050 points

This is not specific to AM64x, in general there is no separate DMA involved in a cache miss. The processor core (in AM6442 case A53 or R5) cache controller is the initiator the fetches or evicts a cache line (64bytes with A53, 32bytes with R5) in a burst. You can think of this cache controller as being a dedicated DMA for just the purpose of reading and writing between main memory and caches.

Pekka

Processors

Processors forum

AM6442: DMA for DDRSS