On Tue, Oct 03, 2017 at 01:24:57PM +0200, Christophe LEROY wrote: >> 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.
