Re: [PATCH 09/21] riscv: dma-mapping: skip invalidation before bidirectional DMA
Conor Dooley <[email protected]> Wed, 29 Mar 2023 21:16:10 +0100
| Newsgroups | io.groups.linux-oxnas,org.infradead.lists.linux-arm-kernel,org.infradead.lists.linux-riscv,org.infradead.lists.linux-snps-arc,org.kernel.vger.linux-csky,org.kernel.vger.linux-hexagon,org.kernel.vger.linux-kernel,org.kernel.vger.linux-m68k,org.kernel.vger.linux-mips,org.kernel.vger.linux-openrisc,org.kernel.vger.linux-parisc,org.kernel.vger.linux-sh,org.kernel.vger.sparclinux,org.ozlabs.lists.linuxppc-dev |
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--Groupsio=fSJCH7eyUODu5KlXAeOC Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Mar 27, 2023 at 02:13:05PM +0200, Arnd Bergmann wrote: > From: Arnd Bergmann <[email protected]> >=20 > For a DMA_BIDIRECTIONAL transfer, the caches have to be cleaned > first to let the device see data written by the CPU, and invalidated > after the transfer to let the CPU see data written by the device. >=20 > riscv also invalidates the caches before the transfer, which does > not appear to serve any purpose. Rationale makes sense to me.. Reviewed-by: Conor Dooley <[email protected]> Thanks for working on all of this Arnd! --Groupsio=fSJCH7eyUODu5KlXAeOC Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZCScigAKCRB4tDGHoIJi 0jHpAP47kMhf2uxHoGKhD+jHsEYnFgTHptLnAfIJV6N+QeFoOAD/YxG6hd8qhesW 6Tw9EqBEW/4auX2CLsbK7xE8fP5A9wg= =os1C -----END PGP SIGNATURE----- --Groupsio=fSJCH7eyUODu5KlXAeOC--