AnsweredAssumed Answered

i.MX CAAM DMA restrictions

Question asked by Vincent Siles on Mar 9, 2018
Latest reply on Mar 12, 2018 by Vincent Siles

Hi !

I'm currently developing a bare metal driver for the CAAM of a i.MX6 board.

For the documentation I see that input/output ring addresses must be 4-byte aligned.

However with this restriction only, I sometime fail to start the RNG component, and the only way to fix things is to have a bigger alignment constraint on these addresses.


In Linux and U-boot, I can see they always allocate buffer with at least 64 byte alignment (even 4k in linux iirc), so I'm wondering if the 4-byte constraint from the documentation is correct or if I need to allocate my buffer with a more restrictive address.