L4Re: Allocating pinned memory and obtaining its physical address

Hello,

Sorry to be lazy and not dig too deeply into the documentation and code, but once upon a time it was possible to use the l4re_ma functions to allocate pinned memory. Then, one would use the dataspace protocol to obtain the physical address of the memory via the capability involved in memory allocation.

This exercise would be sufficient to get into a position to initialise peripherals in a system-on-a-chip, setting registers with the physical memory addresses they would need for things like DMA. The initialisation of things like framebuffers would rely on this procedure.

I see that the "phys" operation in the dataspace protocol was discarded some time ago, and now there is a "DMA space" abstraction instead:

https://l4re.org/doc/group__api__l4re__c__dma.html

Are there any examples of how I might obtain a physical address associated with a block of memory using this new API?

Thanks in advance for any guidance that might be offered!

Paul