[PATCH v4 06/12] ARM: vfp: Remove workaround for Feroceon CPUs

[Arnd Bergmann]

On Tue, Mar 21, 2023, at 16:42, Ard Biesheuvel wrote:
> On Tue, 21 Mar 2023 at 15:44, Linus Walleij <linus.walleij at linaro.org> wrote:

>> I agree, I have one of those systems as my NAS, currently running
>> an (unsupported) version of ArchLinuxARM:
>>
>> $ cat /proc/cpuinfo
>> processor    : 0
>> model name    : Feroceon 88FR131 rev 1 (v5l)
>> BogoMIPS    : 83.33
>> Features    : swp half thumb fastmult edsp
>> CPU implementer    : 0x56
>> CPU architecture: 5TE
>> CPU variant    : 0x2
>> CPU part    : 0x131
>> CPU revision    : 1
>>
>> Hm doesn't even have any VFP, I don't know what spins of this Marvell
>> silicon that even does?
>
> Arnd might have some more insight in that.

I did the research again last week when we discussed this
on IRC. It turns out that the information I had put into
Documentation/arm/marvell.rst is actually correct, and
out of the various Feroceon/Mohawk CPU cores, only the
very last dual-issue "Jolteon" cores have VFP, the
numbers are 88fr571-vd (used in mv78xx0), and
Feroceon-2850 88fr531-vd (used in Orion-2 88F5281,
but not more common Orion 88F518x and Kirkwood).

On a board level, none of the machines using DT have these
chips, the only remaining board files in 6.3 are
TERASTATION_WXL, TERASTATION_PRO2 and TS409. The first
two of those are being actively supported by the
https://github.com/1000001101000/Debian_on_Buffalo
project, but the maintainer confirmed that they don't
expect any user to run VFP-enabled binaries on the
Debian armel distro.

      Arnd