[coreboot] patch: stage 2 ide device for mcp55

Uwe Hermann uwe at hermann-uwe.de
Tue Aug 12 01:12:53 CEST 2008

On Mon, Aug 11, 2008 at 09:03:14AM -0700, ron minnich wrote:
> On Mon, Aug 11, 2008 at 3:20 AM, Carl-Daniel Hailfinger
> > Maybe move the hunk above into an extra function so we can use the
> > generic subsystem ID infrastructure?
> It's gone. There is not one on v3 and I see no need to add it. The
> propagation of subsystem stuff can be done by the dtc, AFAICS. We do
> this:
> 1. add subsystem info to dts and device struct
> 2. allow users to specify subsystem to any node in the dts. All nodes
> under that
>    node will inherit that id unless they similarly set it.
> 3. at the root, we set subsystem to (I assume) mainboard VID and DID
> 4. at flatten tree time, we walk the tree and propagate subsystem VID
> and DID to
> children. This ensures that all devices have it at compile time
> 5. In a final pass at runtime (probably phase6) we walk the tree and,
> for devices that set 'support subsystem VID/DID', we set it into the
> hardware .
> Done. Run time mess becomes compile time mess. Unless I'm missing something.
> If I am, let me know.

Sounds good, but will need some testing on actual hardware, of course.

I think we'll also need a mechanism to 'not set' or 'unset' subsystem
IDs for certain devices. Some (PCI) devices on some chipsets just can't
have subsystem IDs at all, for some we don't know _how_ to set them
(missing datasheets) and some inherit their IDs from other devices and
don't have a mechanism to set their own (e.g. some Intel audio inherits
the subsystem IDs of IDE and similar stuff).

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