Hello, On Sunday, December 11, 2011 11:46 PM Stephen Rothwell wrote: > On Fri, 09 Dec 2011 17:39:56 +0100 Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote: > > > > Introduce new alloc/free/mmap methods that take attributes argument. > > alloc/free_coherent can be implemented on top of the new alloc/free > > calls with NULL attributes. dma_alloc_non_coherent can be implemented > > using DMA_ATTR_NONCOHERENT attribute, dma_alloc_writecombine can also > > use separate DMA_ATTR_WRITECOMBINE attribute. This way the drivers will > > get more generic, platform independent way of allocating dma memory > > buffers with specific parameters. > > > > One more attribute can be usefull: DMA_ATTR_NOKERNELVADDR. Buffers with > > such attribute will not have valid kernel virtual address. They might be > > usefull for drivers that only exports the DMA buffers to userspace (like > > for example V4L2 or ALSA). > > > > mmap method is introduced to let the drivers create a user space mapping > > for a DMA buffer in generic, architecture independent way. > > > > TODO: update all dma_map_ops clients for all architectures > > To give everyone some chance, you should come up with a transition plan > rather than this "attempt to fix everyone at once" approach. You could > (for example) just add the new methods now and only remove them in the > following merge window when all the architectures have had a chance to > migrate. > > And, in fact, (as I presume you know) this patch just breaks everyone > with no attempt to cope. Yes, I know that. Next version will include correct fix for this issue as well as adjustments for other architectures. I was asked to post a current version of DMA-mapping & IOMMU integration patch rebased on the latest kernel and I wanted to this before going for holidays to let others to work with the latest version. Best regards -- Marek Szyprowski Samsung Poland R&D Center -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>