Messages in this thread | | | Subject | Re: [PATCH v3 1/4] iommu/arm-smmu: Add SMMU ID2 register fixup hook | From | Tomasz Nowicki <> | Date | Fri, 3 Jul 2020 11:19:11 +0200 |
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On 03.07.2020 10:24, Robin Murphy wrote: > On 2020-07-02 21:16, Tomasz Nowicki wrote: >> We already have 'cfg_probe' hook which meant to override and apply >> workarounds while probing ID registers. However, 'cfg_probe' is called >> at the very end and therefore for some cases fixing up things becomes >> complex >> or requires exporting of SMMU driver structures. Hence, seems it is >> better and >> cleaner to do ID fixup right away. In preparation for adding Marvell >> errata add an extra ID2 fixup hook. > > Hmm, the intent of ->cfg_probe was very much to give impl a chance to > adjust the detected features before we start consuming them, with this > exact case in mind. Since the Cavium quirk isn't actually doing that - > it just needs to run *anywhere* in the whole probe process - I'm under > no illusion that I put the hook in exactly the right place first time > around ;) > > The diff below should be more on the mark... > > Robin. > > ----->8----- > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index 243bc4cb2705..884ffca5b1eb 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -1891,6 +1891,9 @@ static int arm_smmu_device_cfg_probe(struct > arm_smmu_device *smmu) > smmu->features |= ARM_SMMU_FEAT_FMT_AARCH64_64K; > } > > + if (smmu->impl && smmu->impl->cfg_probe) > + return smmu->impl->cfg_probe(smmu); > + > /* Now we've corralled the various formats, what'll it do? */ > if (smmu->features & ARM_SMMU_FEAT_FMT_AARCH32_S) > smmu->pgsize_bitmap |= SZ_4K | SZ_64K | SZ_1M | SZ_16M; > @@ -1909,7 +1912,6 @@ static int arm_smmu_device_cfg_probe(struct > arm_smmu_device *smmu) > dev_notice(smmu->dev, "\tSupported page sizes: 0x%08lx\n", > smmu->pgsize_bitmap); > > - > if (smmu->features & ARM_SMMU_FEAT_TRANS_S1) > dev_notice(smmu->dev, "\tStage-1: %lu-bit VA -> %lu-bit IPA\n", > smmu->va_size, smmu->ipa_size); > @@ -1918,9 +1920,6 @@ static int arm_smmu_device_cfg_probe(struct > arm_smmu_device *smmu) > dev_notice(smmu->dev, "\tStage-2: %lu-bit IPA -> %lu-bit PA\n", > smmu->ipa_size, smmu->pa_size); > > - if (smmu->impl && smmu->impl->cfg_probe) > - return smmu->impl->cfg_probe(smmu); > - > return 0; > } >
I was under impression that ->cfg_probe was meant for Cavium alike errata (position independent). Then I will move ->cfg_probe as you suggested. I prefer not to add yet another impl hook too :)
Thanks, Tomasz
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