Re: [PATCH v3 06/11] dt-bindings: PCI: Update the RK3399 example to a valid one

[Rick Wertenbroek]

On Tue, Apr 4, 2023 at 3:29 PM Krzysztof Kozlowski
<krzysztof.kozlowski@xxxxxxxxxx> wrote:
>
> On 04/04/2023 10:58, Rick Wertenbroek wrote:
> > On Tue, Apr 4, 2023 at 10:45 AM Krzysztof Kozlowski
> > <krzysztof.kozlowski@xxxxxxxxxx> wrote:
> >>
> >> On 04/04/2023 10:24, Rick Wertenbroek wrote:
> >>> Update the example in the documentation a valid example.
> >>> The default max-outbound-regions is 32 but the example showed 16.
> >>
> >> This is not reason to be invalid. It is perfectly fine to change default
> >> values to desired ones. What is not actually obvious is to change some
> >> value to a default one, instead of removing it...
> >
> > Hello, the example value <0x0 0x80000000 0x0 0x20000>; is plain wrong
> > and will crash the kernel. This is a value that point to an address that falls
> > in the DDR RAM region but depending on the amount of RAM on the
> > board this address may not even exist (e.g., board with 2GB or less).
>
> We talk about max-outbound-regions.

Okay, sorry, I didn't get that, you are right, there is nothing wrong with 16.
I'll remove that change and leave it be.

>
> >
> > Also this address requires pointing to where the PCIe controller has the
> > windows from AXI Physical space to PCIe space. This address is
> > allocated when the SoC address map is created so it can only be that
> > one unless rockchip refabs the SoC with another address map.
> >
> > The example never worked with the values given as reported by e.g.,
> > https://stackoverflow.com/questions/73586703/device-tree-issues-with-rockpro64-pcie-endpoint
> > and here they set it to 0 (base of the DDR, which is a "valid" address
> > as to it exists even on boards with less than 2GB) but it is still wrong
> > to do so.
>
> Again, my comment was under max-outbound-regions, not under some other
> pieces. Does this all apply?
>
> Best regards,
> Krzysztof
>

I'll remove the change to the max-outbound-regions, it is not needed.
I'll place the registers as second parameter, both on the dtsi entry and here.
I'll keep the change to the register value because it is necessary along
with the added pinctrl.

This will simplify the patch, avoid unnecessary changes, and make
things clearer.

Sorry for the misunderstanding.
Regards,
Rick