On Thu, 2015-04-02 at 18:15 -0400, Sowmini Varadhan wrote: > On (04/03/15 08:57), Benjamin Herrenschmidt wrote: > > > > > > I only just noticed too, you completely dropped the code to honor > > > > the dma mask. Why that ? Some devices rely on this. > > /* Sowmini's comment about this coming from sparc origins.. */ > > > Probably, not that many devices have limits on DMA mask but they do > > exist. It becomes more important if we decide to create a very large > > IOMMU window that spans beyond 4G in order to support devices with > > 32-bit DMA masks. Otherwise it's older devices mostly with <32-bit > > masks. > > > > In any case, for a generic piece of code, this should be supported. > > Basically, assume that if we have something in the powerpc code, we need > > it, if you remove it, we won't be able to use your code generically. > > I see. > > is the mask something that can be stored in the iommu_map_table as > part of the init? > No, the mask is per device and has to be retrieved from the device. Additionally the mask used for dma_map_* can be different from the consistent mask used for alloc_coherent (we have a bug there on powerpc which I'm trying to fix btw). So it should be passed as an argument by the caller. > I can see that the align_order has to be an additional arg to > iommu_tbl_range_alloc, not sure if mask falls in that category > as well. It does. Cheers, Ben. -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
