Re: [PATCH] powerpc/85xx: P2020: Add law_trgt_if property to PCIe DT nodes

[Pali Rohár]

On Thursday 05 May 2022 10:40:09 Rob Herring wrote:
> On Wed, May 4, 2022 at 1:09 PM Pali Rohár <pali@xxxxxxxxxx> wrote:
> >
> > DT law_trgt_if property defines Local Access Window Target Interface.
> 
> Documentation?

I was not able to find it :-( So the only documentation for me was the
source code and decoding how it works and how it is used.

> fsl,law-trgt-if would be the preferred form.
> 
> > Local Access Window Target Interface is used for identifying individual
> > peripheral and mapping its memory to CPU. Interface id is defined by
> > hardware itself.
> 
> Normally, we avoid instance indices like this, but if it is more than
> just documentation convention maybe that's fine.
> 
> Rob

It is id defined by HW. Software needs to know how to pair DT node with
address range defined in "ranges" to the correct HW PCIe controller.