On Fri, 2009-05-22 at 19:55 -0400, Jeremy Fitzhardinge wrote: > Ian Campbell wrote: > > On Thu, 2009-05-21 at 14:27 -0400, Becky Bruce wrote: > > > >> I can work with that, but it's going to be a bit inefficient, as I > >> actually need the dma_addr_t, not the phys_addr_t, so I'll have to > >> convert. In every case, this is a conversion I've already done and > >> that I need in the calling code as well. > >> > > > > Does > > > > dma_addr_t dma_map_range(struct device *hwdev, phys_addr_t addr, > > size_t size); > > > > work for you? > > > > If the range does not need mapping then it returns the dma address, if > > you needed to calculate the dma address anyway to figure out if mapping > > is required then this is fine. If the range does need mapping then it > > returns NULL. > > > > My only concern is whether dma_addr_t == 0 is actually equivalent to > NULL. That is, can we be sure that address 0 will never be used?
It seems not, ~0UL might have been an option, but... > Taking dma_alloc_coherent as a model, we could have something like: > > int dma_map_range(struct device *hwdev, phys_addr_t addr, size_t size, > dma_addr_t *dma_addrp); > > > where *dma_addrp is set if the function returns success (bool return > type might be clearer). ... this sounds like a good idea to me. Ian. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
