On Sun, 16 Apr 2023 23:53:17 PDT (-0700), Christoph Hellwig wrote:
On Wed, Apr 12, 2023 at 09:32:30PM +0100, Conor Dooley wrote:
On Wed, Apr 12, 2023 at 12:08:53PM +0100, Prabhakar wrote:
> Note,
> - This series requires testing on Cores with zicbom and T-Head SoCs
As I said last time, I dunno what actual Zicbom stuff exists, other than
perhaps the Ventana lads having something. I did some tyre kicking on my
D1 and it was fine, although nothing has actually changed materially for
either of them with this series in v8..
And as saying before, there is absolutely no reason to add non-standard
non-coherent DMA support and let this cancer creep. If you want Linux
support implement Zicbom, be that in hardware or the SBI.
IMO we should just take the support in Linux: trying to hide stuff behind the
SBI leads to more more headaches than it's worth, we end up with a bunch of
broken firmware to try and work around. We've already got a mess here because
of the D1 support, we might as well just live with it.
In practice there's just going to be a ton of mess in arch/riscv, as the ISA
has been missing many core features for many years and hardware vendors are
allowed to do whatever they want. That's obviously a huge headache, but I
think there's nothing we can really do about it.
