> -----Original Message----- > From: grundler@xxxxxxxxxx [mailto:grundler@xxxxxxxxxx] On Behalf Of Grant Grundler > Sent: Wednesday, August 07, 2013 1:07 AM > To: Marek Szyprowski > > Hi Marek, > > On Tue, Aug 6, 2013 at 6:17 AM, Marek Szyprowski > <m.szyprowski@xxxxxxxxxxx> wrote: > ... > > IMHO it is much better to have a simple driver, which binds to a single > > IOMMU controller and leave it to the driver whether to have a same virtual address > > space for all parts of FIMC-IS or MFC submodules/memory ports or not. > > I understand this part. I having written the IOMMU support for 4 > different IOMMUs, all of which had exactly one IO Page Table and one > IOMMU shared by many devices. > > > Just make sure that it will be possible to attach more than one sysmmu > > controller to one iommu domain. > > I don't understand how this is possible. Can someone explain this > better in the IOMMU documentation please? System MMU is dedicated to a master H/W such as FIMD and FIMC. Thus, attaching a master H/W to an iommu domain can be thought as attaching a System MMU to an iommu domain even though such thinking is not correct view of the relationship between iommu domain and System MMU. > > "iommu domain" to me means one virtual IO address space for attached > devices that can master DMA transactions. The IOMMU then uses it's IO > Page Table to translate the DMA address to the system physical address > space and forwards the transaction. > > What is the role of the sysmmu in all of this? > Is the sysmmu just the MMU (or collection of MMU) for host DRAM? > Or is sysmmu responsible for "other stuff"? (clocks, power domains, MMU, etc) > System MMU is responsible for address translation of traffic from a master H/W which the System MMU is dedicated to. > I can understand we might have multiple MMUs in a system...e.g. every > range of memory might have it's own MMU. But they share the same > physical address space and generally live under one page table. > Because of "one page table" I would consider them one entity from the > the IOMMUs perspective. Sorry, I don't understand. Do you mean you are thinking that it is better to share one page table by all IOMMUs in a system? Thank you, KyongHo > > thanks, > grant -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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