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

From: Laura Abbott
Date: Tue Sep 13 2016 - 11:02:35 EST

On 09/13/2016 02:19 AM, Will Deacon wrote:
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?

I proposed that in V1 and it was suggested I make it a proper API