Re: [net-next: PATCH 09/12] Documentation: ACPI: DSD: introduce DSA description

From: Andrew Lunn
Date: Tue Jun 21 2022 - 07:18:57 EST


On Tue, Jun 21, 2022 at 02:09:14PM +0300, Andy Shevchenko wrote:
> On Mon, Jun 20, 2022 at 09:47:31PM +0200, Andrew Lunn wrote:
>
> ...
>
> > > + Name (_CRS, ResourceTemplate ()
> > > + {
> > > + Memory32Fixed (ReadWrite,
> > > + 0xf212a200,
> > > + 0x00000010,
> >
> > What do these magic numbers mean?
>
> Address + Length, it's all described in the ACPI specification.

The address+plus length of what? This device is on an MDIO bus. As
such, there is no memory! It probably makes sense to somebody who
knows ACPI, but to me i have no idea what it means.

> Or if you asked
> why the values there are the particular numbers? I guess it's fined to have
> anything sane in the example. OTOH a comment may be added.
>
> > > + )
> > > + })
>
> ...
>
> > > + Device (SWI0)
> > > + {
> > > + Name (_HID, "MRVL0120")
> > > + Name (_UID, 0x00)
> > > + Name (_ADR, 0x4)
> > > + <...>
> > > + }
> >
> > I guess it is not normal for ACPI, but could you add some comments
> > which explain this. In DT we have
> >
> > properties:
> > reg:
> > minimum: 0
> > maximum: 31
> > description:
> > The ID number for the device.
> >
> > which i guess what this _ADR property is, but it would be nice if it
> > actually described what it is supposed to mean. You have a lot of
> > undocumented properties here.
>
> Btw, you are right, _ADR mustn't go together with _HID/_CID.

Does ACPI have anything like .yaml to describe the binding and tools
to validate it?

Andrew