Antwort: Re: [PATCH v1] x86: acpi: Refactor XSDT handling in acpi_add_table()

[Wolfgang Wallner <wolfgang.wallner@br-automation.com>]

Hi Andy,

-----"U-Boot" <u-boot-bounces@lists.denx.de> schrieb: -----
>
> [snip]
> 
> > > > > P.S. Briefly looking at the last ~30 patches I can say that the idea
> > > > > looks good, implementation needs more work. For example, there is
> > > > > 'linux,name' property. Shouldn't be referred at all. Linux names and
> > > > > other type of enumerations is utterly opaque to the outside world.
> > > >
> > > > How do we add the required linux,name ACPI property into the ACPI
> > > > tables for a device?
> > >
> > > There must not be Linux device names or anything Linux related (like
> > > hardcoded GPIO numbers) in the ACPI table.
> >
> > Apparently the Intel GPIO driver requires that name. See for example here:
> >
> > https://elixir.bootlin.com/linux/latest/source/drivers/pinctrl/intel/pinctrl-broxton.c#L999
> >
> > static const struct acpi_device_id bxt_pinctrl_acpi_match[] = {
> > { "INT3452", (kernel_ulong_t)apl_pinctrl_soc_data },
> > { "INT34D1", (kernel_ulong_t)bxt_pinctrl_soc_data },
> > { }
> > };
> >
> > So we have to put INT3452 in the ACPI table.
> 
> Wait, this is not a *name*, this is ACPI _HID. ACPI _HID, of course,
> should be somewhere in board code.
> 
> I was thinking myself about some U-Boot framework that actually takes
> ACPI _HID from the driver. So, when you define in U-Boot device tree a
> compatible string (for U-Boot use), in the driver it will have in the
> class structure the callback / field / stubstructure to use when ACPI
> generate tables is enabled. It will drop duplication of compatible
> with ACPI _HID in each DTS.

There is a related discussion in another thread, here is the link:
https://lists.denx.de/pipermail/u-boot/2020-February/398856.html

I have brought that up, but I'm no expert in this area, so any feedback would
be welcome.

That discussion is not only about inferring _HID, but also about the idea of
inferring other ACPI properties from device tree (the example discussed is the
HID offset).

regards, Wolfgang