Re: [PATCH] LoongArch: Make WriteCombine configurable for ioremap()

From: Xi Ruoyao
Date: Tue Mar 14 2023 - 06:12:02 EST


On Tue, 2023-03-14 at 18:02 +0800, Huacai Chen wrote:
> > Hmm, is it possible to make a PCI quirk so SUC/WUC will be decided
> > automatically from the vendor:device ID of the PCI root controller?
> > Then we don't need to rely on the user or distro maintainer to select an
> > option.  I see there is already many architecture-dependant #if
> > directives in drivers/pci/quirks.c so I guess such a quirk is acceptable
> > in PCI tree...
> Not a good idea, pci quirks need too long a time to review, and we
> don't know when this issue can be fixed in hardware.

How about make a PCI fixup in arch/loongarch/pci/pci.c then? I think we
just need to set a flag in the fixup, then check the flag in
ioremap_wc...

--
Xi Ruoyao <xry111@xxxxxxxxxxx>
School of Aerospace Science and Technology, Xidian University