Re: [PATCH 15/21] ARM: dma-mapping: always invalidate WT caches before DMA

Linus Walleij <[email protected]> Fri, 31 Mar 2023 11:01:51 +0200

Newsgroups	gmane.linux.ports.ppc.embedded,gmane.linux.ports.sh.devel,gmane.linux.ports.mips,gmane.linux.ports.sparc,gmane.linux.ports.riscv,gmane.linux.kernel.arc,gmane.linux.ports.arm.kernel,gmane.linux.ports.parisc,gmane.linux.kernel,gmane.linux.ports.hexagon
Message-ID	<CACRpkdbMry_UUYN1MuXTUpRXV+Tj9RSDvN-iBdvR8hDfkTaX4w@mail.gmail.com>

On Mon, Mar 27, 2023 at 2:16 PM Arnd Bergmann <[email protected]> wrote:

> From: Arnd Bergmann <[email protected]>
>
> Most ARM CPUs can have write-back caches and that require
> cache management to be done in the dma_sync_*_for_device()
> operation. This is typically done in both writeback and
> writethrough mode.
>
> The cache-v4.S (arm720/740/7tdmi/9tdmi) and cache-v4wt.S
> (arm920t, arm940t) implementations are the exception here,
> and only do the cache management after the DMA is complete,
> in the dma_sync_*_for_cpu() operation.
>
> Change this for consistency with the other platforms. This
> should have no user visible effect.
>
> Signed-off-by: Arnd Bergmann <[email protected]>

Looks good to me.
Reviewed-by: Linus Walleij <[email protected]>

Yours,
Linus Walleij