Re: [RFCv3][PATCH 3/5] arm64: Implement ARCH_HAS_FORCE_CACHE

[Will Deacon]

Hi Laura,

On Mon, Sep 12, 2016 at 02:32:56PM -0700, Laura Abbott wrote:
> 
> arm64 may need to guarantee the caches are synced. Implement versions of
> the kernel_force_cache API to allow this.
> 
> Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
> ---
> v3: Switch to calling cache operations directly instead of relying on
> DMA mapping.
> ---
>  arch/arm64/include/asm/cacheflush.h |  8 ++++++++
>  arch/arm64/mm/cache.S               | 24 ++++++++++++++++++++----
>  arch/arm64/mm/flush.c               | 11 +++++++++++
>  3 files changed, 39 insertions(+), 4 deletions(-)

I'm really hesitant to expose these cache routines as an API solely to
support a driver sitting in staging/. I appreciate that there's a chicken
and egg problem here, but we *really* don't want people using these routines
in preference to the DMA API, and I fear that we'll simply grow a bunch
more users of these things if we promote it as an API like you're proposing.

Can the code not be contained under staging/, as part of ion?

Will