| Date | Wed, 29 Mar 2023 21:16:10 +0100 | From | Conor Dooley <> | Subject | Re: [PATCH 09/21] riscv: dma-mapping: skip invalidation before bidirectional DMA |
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On Mon, Mar 27, 2023 at 02:13:05PM +0200, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > 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. > > 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 <conor.dooley@microchip.com>
Thanks for working on all of this Arnd! [unhandled content-type:application/pgp-signature] |