Re: [PATCH v2 3/3] usb/hcd-xhci: Split pci wrapper for xhci base model

[Gerd Hoffmann]

  Hi,

> > >> Do you intend to add a "sysbus model" in a future patch?
> > > [Sai Pavan Boddu]  Yes. I would be sending it along with that a device
> > > which would be using it. (i.e for zynqmp soc ) Let me know, if its good to
> > include hcd-xhci-sysbus.c here ?

I think this would be useful, to see how the code separation plays out
on the sysbus side.

> > Here's a clean way to provide different bus connectors (say PCI and
> > sysbus) for the same core device:
> > 
> > Make the core device a TYPE_DEVICE.
> > 
> > For each desired bus, have a bus-specific device that contains a core 
> > device.
> > Use object_initialize_child() for the component.

> This was my V1 implementation.
> Changed it to non-qom structure after some feedback from @Gred. Felt like 
> XHCIState will not be used standalone.

> > Example: core device TYPE_SERIAL, PCI device TYPE_PCI_SERIAL, ISA device
> > TYPE_ISA_SERIAL, sysbus devices TYPE_SERIAL_IO. TYPE_SERIAL_MM.

/me goes check out the serial code ...

For reference: commit which transforms serial into the structure
above is this:

    commit 7781b88ee458ff933459503ade0b0a6ddaad08de
    Author: Marc-André Lureau <marcandre.lureau@redhat.com>
    Date:   Mon Oct 21 23:32:12 2019 +0200

        serial: initial qom-ification

Note that this patch doesn't change structs, so ISASerialState still
looks this way:

struct ISASerialState {
    ISADevice parent_obj;
    [ ... ]
    SerialState state;
};

So you can likewise keep your current "struct XHCIPciState" struct
layout and still turn XHCIState into a device object.  Which is nice to
have as it better models the hardware (xhci core behind pci connector).

take care,
  Gerd