Re: fu740 target

[Bin Meng]

On Wed, Jul 27, 2022 at 10:44 PM Ben Dooks <ben.dooks@codethink.co.uk> wrote:
>
> On 27/07/2022 15:38, Bin Meng wrote:
> > On Wed, Jul 27, 2022 at 10:24 PM Ben Dooks <qemu@ben.fluff.org> wrote:
> >>
> >> Is anyone working on adding a sifive-u74 core to the list of supported
> >> CPU types? I was looking at full emulation of the Unmatched but at the
> >> moment the best we have is sifive-u54 and I think that misses at least
> >> two CSRs the sifive-u74 has.
> >>
> >> Does anyone have plans to add the sifive-u74, and if not, would a plan
> >> to add gradual support for it like adding CSRs 0x7c1 and 0x7c2 so we
> >> can run an Unmatched U-boot SPL against it.
> >
> > Adding 0x7c1/7c2 would be a vendor-specific CSR approach?
>
> Part of the FU740 feature disable controls

Yep I know that. I was asking if you use a vendor-specific CSR
approach in QEMU to handle such cleanly.

>
> >>
> >> If not, is there a definitive U54->U74 set of public differnces around
> >> we could use to start from? I'd like to be able to run a full Unmatched
> >> image using qemu at some point to add to the current real-board testing
> >> we're doing.
> >>
> >> (I have a basic addition of the type and the two CSRs as a couple of
> >> patches if that would help as a start)
> >>
> >
> > I am not aware of anyone doing U74 modeling in QEMU, but SiFive folks
> > (+Frank) may have one downstream as I see they posted several bug
> > fixes in the existing U54 model.
> >

Regards,
Bin