On Wed, Jan 27, 2021 at 07:32:55PM +0800, Zhen Lei wrote: > v2 --> v3: > Patch 3 is updated because https://lkml.org/lkml/2021/1/22/532 has been > queued in advance. > > v1 --> v2: > According to Robin Murphy's suggestion: https://lkml.org/lkml/2021/1/20/470 > Don't reserve the PMCG register spaces, and reserve the entire SMMU register > space. > > v1: > Since the PMCG may implement its resigters space(4KB Page0 and 4KB Page1) > within the SMMUv3 64KB Page0. In this case, when the SMMUv3 driver reserves > the > 64KB Page0 resource in advance, the PMCG driver try to reserve its Page0 and > Page1 resources, a resource conflict occurs. > > commit 52f3fab0067d6fa ("iommu/arm-smmu-v3: Don't reserve implementation > defined register space") reduce the resource reservation range of the SMMUv3 > driver, it only reserves the first 0xe00 bytes in the 64KB Page0, to avoid > the above-mentioned resource conflicts. > > But the SMMUv3.3 add support for ECMDQ, its registers space is also > implemented > in the SMMUv3 64KB Page0. This means we need to build two separate mappings. > New features may be added in the future, and more independent mappings may be > required. The simple problem is complicated because the user expects to map > the > entire SMMUv3 64KB Page0. > > Therefore, the proper solution is: If the PMCG register resources are located > in > the 64KB Page0 of the SMMU, the PMCG driver does not reserve the conflict > resources > when the SMMUv3 driver has reserved the conflict resources before. Instead, > the PMCG > driver only performs devm_ioremap() to ensure that it can work properly. > > Zhen Lei (3): > perf/smmuv3: Don't reserve the PMCG register spaces > perf/smmuv3: Add a MODULE_SOFTDEP() to indicate dependency on SMMU > iommu/arm-smmu-v3: Reserving the entire SMMU register space
I'll need Robin's ack on these. Will
