Re: [PATCH 07/11] powerpc: make dma_cache_sync a no-op
From: Christoph Hellwig <hch@lst.de>
Date: 2017-10-03 11:43:33
Also in:
linux-iommu, linux-mips, linux-sh, linuxppc-dev
On Tue, Oct 03, 2017 at 01:24:57PM +0200, Christophe LEROY wrote:
quoted
powerpc does not implement DMA_ATTR_NON_CONSISTENT allocations, so it doesn't make any sense to do any work in dma_cache_sync given that it must be a no-op when dma_alloc_attrs returns coherent memory.What about arch/powerpc/mm/dma-noncoherent.c ? Powerpc 8xx doesn't have coherent memory.
It doesn't implement the DMA_ATTR_NON_CONSISTENT interface either, so if it really doesn't have a way to provide dma coherent allocation (although the code in __dma_alloc_coherent suggests it does provide dma coherent allocations) I have no idea how it could ever have worked.