On Tue, Sep 21, 2010 at 5:05 PM, Dan Malek <[email protected]> wrote:
> The DMA descriptors are accessed using DMA by the > controller itself. Yes and no. Technically, it is DMA, but it's not something that SWIOTLB could ever know about. We just pass the physical address to the DMA controller, and it does a memory read to obtain the data. That's not the kind of DMA that SWIOTLB would deal with, I think. > The APIs need to ensure proper coherency > between the CPU and the DMA controller for the > descriptor access. The underlying implementation of the > API will depend upon the hardware capabilities that > ensure this coherency. I think that's already covered. The dma_set_mask() call is supposed to only affect the dma_map_single() calls that dmaengine makes, as Scott pointed out. My question is, should dmaengine be using the same 'dev' that fsldma uses to allocate the DMA descriptors? I wonder if the 'dev' should be allocated internally by dmaengine, or provided by the client drivers. -- Timur Tabi Linux kernel developer at Freescale _______________________________________________ Linuxppc-dev mailing list [email protected] https://lists.ozlabs.org/listinfo/linuxppc-dev
