On Tue, Jan 24, 2012 at 03:46:01PM +0200, Felipe Balbi wrote: > On Tue, Jan 24, 2012 at 02:41:21PM +0100, Hiroshi Doyu wrote: > > Actually I really like the concept of this "domain" now, which hides > > the H/W hierarchy from users. > > > > But in Tegra SMMU/GART case, there's a single one IOMMU device in the > > system. Keeping a iommu device list in a domain and iterating iommu > > device list in each iommu_ops seem to be so nice, but I'm afraid that > > this may be a bit too much when one already knows that there's only > > one IOMMU device in the system. > > > > If there's no actual problem for 1-1 mapping between IOMMU H/Ws and > > domains, I think that it may not so bad to keep the original code(1-1) > > for GART and SMMU. What do you think? > > I think it boils down to "extensability". If you can truly/fully > guarantee that there will *always* be a single IOMMU on all upcoming > Tegras, then it's really overkill. > > But if there's even a remote possibility of the HW being changed and you > end up with more IOMMUs, things start to feel necessary for the sake of > making it easy to extend. Right. But I am fine with the logic as-is when there is only one SMMU in the system. But please also change the IOMMU driver so that it really only initializes a single SMMU. When boards pop up with more than one you we notice that assumption in the code again and are reminded to change it. Joerg -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
