Re: Dealing with custom hardware on x86

From: Pavel Machek
Date: Wed Nov 24 2021 - 05:47:32 EST


Hi!

> I'm about to start a project involving custom hardware using an x86 CPU.
> Complicating things somewhat we will have a CPU board supplied by a 3rd
> party vendor using a COM Express type 7 connector which will plug in to
> the board we're designing (actually 2 different boards each with some
> modular aspects) .
>
> Coming from an embedded (mostly ARM) background I'm used to describing
> the hardware via a devicetree and dealing with plug-in modules by
> loading devicetree overlays. How do people achieve this kind of thing on
> x86?
>
> I gather ACPI is involved somewhere but the knowledge that the BIOS has
> will go as far as the COM Express header and somehow we'll have to tell
> the kernel about the various non-probeable (mostly i2c) devices on our
> board which is kind of where I'm stuck. Any pointers would be greatly
> appreciated.

In x86 land, we usually use PCI/PCIE and have a add-on board expose
unique IDs with driver knowing what the IDs are. ACPI should not be
involved for add-on boards.

Best regards,
Pavel
--
http://www.livejournal.com/~pavelmachek

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