Re: [PATCH] arm:swiotlb:keep disabled in default configuration
From: Stefano Stabellini
Date: Thu Jun 23 2016 - 12:00:37 EST
On Thu, 23 Jun 2016, Stefano Stabellini wrote:
> On Jun 23, 2016 8:27 AM, "Manjeet Pawar" <manjeet.p@xxxxxxxxxxx> wrote:
> >
> > From: Rohit Thapliyal <r.thapliyal@xxxxxxxxxxx>
> >
> > swiotlb implementation not required to be enabled in arm and
> > disabling it reduces uImage size by 16KB.
> >
>
> How so? There are no DMA operations on ARM?
Xen actively uses the swiotlb on ARM, see
arch/arm64/include/asm/dma-mapping.h:get_dma_ops
arch/arm/xen/mm.c:xen_swiotlb_dma_ops
> > Signed-off-by: Rohit Thapliyal <r.thapliyal@xxxxxxxxxxx>
> > Signed-off-by: Ajeet Kumar Yadav <ajeet.y@xxxxxxxxxxx>
> > ---
> > arch/arm/Kconfig | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index 90542db..ae65f29 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -1754,7 +1754,7 @@ config SECCOMP
> > defined by each seccomp mode.
> >
> > config SWIOTLB
> > - def_bool y
> > + def_bool n
> >
> > config IOMMU_HELPER
> > def_bool SWIOTLB
> > --
> > 1.7.9.5
> >
>