27.04.2021 21:30, Krishna Reddy пишет: >> Is it always safe to enable SMMU ASID in a middle of a DMA request made by a >> memory client? > > From MC point of view, It is safe to enable and has been this way from many > years in downstream code for display engine. > It doesn't impact the transactions that have already bypassed SMMU before > enabling SMMU ASID. > Transactions that are yet to pass SMMU stage would go through SMMU once SMMU > ASID is enabled and visible.
Hello, Thank you for the answer. Could you please give more information about: 1) Are you on software or hardware team, or both? 2) Is SMMU a third party IP or developed in-house? 3) Do you have a direct access to HDL sources? Are you 100% sure that hardware does what you say? 4) What happens when CPU writes to ASID register? Does SMMU state machine latch ASID status (making it visible) only at a single "safe" point? _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
