Re: [PATCH v4 10/13] hw/riscv/atlantis: Add PCIe controller

[Nicholas Piggin <npiggin@gmail.com>]

On Thu, Apr 30, 2026 at 10:04:16AM +1000, Alistair Francis wrote:
> On Sat, Apr 25, 2026 at 11:21 PM Joel Stanley <joel@jms.id.au> wrote:
> >
> > From: Nicholas Piggin <npiggin@gmail.com>
> >
> > Atlantis has 3 DesignWare PCIe host controllers, however the boot firmware
> > has not been tested with the QEMU DesignWare model so a generic ECAM
> > controller is used for the interim. The system bus aperture and PCIe IO
> 
> I don't follow.
> 
> The actual hardware has a different PCIe controller? This is user
> visible so you can't easily change it once it's merged. Generally user
> visible changes go through a deprecation process, we have some
> exceptions for soft cores which change all the time. But ideally this
> should model the hardware from the start.
> 
> Also if it isn't that should be noted in the board documentation.

Yeah, this was me punting on doing the designware host to get some IOMMU
modeling and driver code tested. And generally being easier to test
other things if we have PCI up.

I hadn't really considered the stability / deprecation issue with
upstreaming it.

> A quick grep shows support for a DesignWare PCIe Host, why not use that?

We should be, I'll take another look at it. We could drop this and the
functional test that uses disk, for now.

Thanks,
Nick