Re: [Qemu-devel] [PATCH v4] hw/arm: Add arm SBSA reference machine

[Leif Lindholm]

On Fri, Nov 16, 2018 at 02:04:07PM -0800, Ard Biesheuvel wrote:
> > > > What is this using the exynos4210 USB device for? That
> > > > is definitely not correct for a generic board.
> > > >
> > > Checked the code:
> > > #define TYPE_SYS_BUS_EHCI "sysbus-ehci-usb"
> > > #define TYPE_EXYNOS4210_EHCI "exynos4210-ehci-usb"
> > > #define TYPE_TEGRA2_EHCI "tegra2-ehci-usb"
> > > #define TYPE_PPC4xx_EHCI "ppc4xx-ehci-usb"
> > > #define TYPE_FUSBH200_EHCI "fusbh200-ehci-usb"
> > >
> > > The first one seems only a parent type, not a general instance, cannot
> > > be used directly.
> > > The other four are specific instances using the first as parent type,
> > > one of them can be chosen to use.
> > > That is my understanding, any comments, or do we need to implement one
> > > which seems generic?
> >
> > I think what we *really* want is sysbus-xhci-generic.
> >
> > That'll be a bit more work though as xhci core and xhci pci needs to be
> > splitted, simliar to how it was done for ehci in commit
> > 5010d4dc618b6b8e7c21129c487c06f6493f71fc (and related patches).
> >
> > Or just plug qemu-xhci into a pcie slot.  Not sure which would be closer
> > to physical hardware.
> 
> We don't need XHCI especially, EHCI is perfectly fine as well.
> 
> This is mostly about ensuring that the emulated hardware spans the
> space of what we encounter on real hardware, and non-PCIE SATA and USB
> controllers is something we see often.
> 
> So I could live with MMIO SATA and PCI USB as well, but I'd prefer it
> if we could have both MMIO.

I would actually strongly prefer non-MMIO.

What "we see" is generally a result of embedded companies "value
adding" in the usual way when moving from embedded to servers.

I want the SBSA target to be an idealised machine, not an educational
vehicle for showing how companies have got it wrong.

Where in doubt, anything software discoverable should win over
non-discoverable.

/
    Leif