Messages in this thread Patch in this message | | | Subject | Re: [PATCH v4 2/4] iommu/arm-smmu: Workaround for Marvell Armada-AP806 SoC erratum #582743 | From | Robin Murphy <> | Date | Wed, 15 Jul 2020 11:32:30 +0100 |
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On 2020-07-15 08:06, Tomasz Nowicki wrote: > From: Hanna Hawa <hannah@marvell.com> > > Due to erratum #582743, the Marvell Armada-AP806 can't access 64bit to > ARM SMMUv2 registers. > > Provide implementation relevant hooks: > - split the writeq/readq to two accesses of writel/readl. > - mask the MMU_IDR2.PTFSv8 fields to not use AArch64 format (but > only AARCH32_L) since with AArch64 format 32 bits access is not supported. > > Note that most 64-bit registers like TTBRn can be accessed as two 32-bit > halves without issue, and AArch32 format ensures that the register writes > which must be atomic (for TLBI etc.) need only be 32-bit.
Thanks Tomasz, this has ended up as clean as I'd hoped it could, and there's still room to come back and play more complicated games later if a real need for AARCH64_64K at stage 2 crops up.
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> Signed-off-by: Hanna Hawa <hannah@marvell.com> > Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com> > Signed-off-by: Tomasz Nowicki <tn@semihalf.com> > --- > Documentation/arm64/silicon-errata.rst | 3 ++ > drivers/iommu/arm-smmu-impl.c | 45 ++++++++++++++++++++++++++ > 2 files changed, 48 insertions(+) > > diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst > index 936cf2a59ca4..157214d3abe1 100644 > --- a/Documentation/arm64/silicon-errata.rst > +++ b/Documentation/arm64/silicon-errata.rst > @@ -125,6 +125,9 @@ stable kernels. > | Cavium | ThunderX2 Core | #219 | CAVIUM_TX2_ERRATUM_219 | > +----------------+-----------------+-----------------+-----------------------------+ > +----------------+-----------------+-----------------+-----------------------------+ > +| Marvell | ARM-MMU-500 | #582743 | N/A | > ++----------------+-----------------+-----------------+-----------------------------+ > ++----------------+-----------------+-----------------+-----------------------------+
And in case anyone feels like nit-picking the order here, I think the current respective corporate structures perfectly justify "Marvell" sorting alphabetically before "NXP", to be next to "Cavium" :D
Robin.
> | Freescale/NXP | LS2080A/LS1043A | A-008585 | FSL_ERRATUM_A008585 | > +----------------+-----------------+-----------------+-----------------------------+ > +----------------+-----------------+-----------------+-----------------------------+ > diff --git a/drivers/iommu/arm-smmu-impl.c b/drivers/iommu/arm-smmu-impl.c > index c75b9d957b70..59422cb92488 100644 > --- a/drivers/iommu/arm-smmu-impl.c > +++ b/drivers/iommu/arm-smmu-impl.c > @@ -147,6 +147,48 @@ static const struct arm_smmu_impl arm_mmu500_impl = { > .reset = arm_mmu500_reset, > }; > > +static u64 mrvl_mmu500_readq(struct arm_smmu_device *smmu, int page, int off) > +{ > + /* > + * Marvell Armada-AP806 erratum #582743. > + * Split all the readq to double readl > + */ > + return hi_lo_readq_relaxed(arm_smmu_page(smmu, page) + off); > +} > + > +static void mrvl_mmu500_writeq(struct arm_smmu_device *smmu, int page, int off, > + u64 val) > +{ > + /* > + * Marvell Armada-AP806 erratum #582743. > + * Split all the writeq to double writel > + */ > + hi_lo_writeq_relaxed(val, arm_smmu_page(smmu, page) + off); > +} > + > +static int mrvl_mmu500_cfg_probe(struct arm_smmu_device *smmu) > +{ > + > + /* > + * Armada-AP806 erratum #582743. > + * Hide the SMMU_IDR2.PTFSv8 fields to sidestep the AArch64 > + * formats altogether and allow using 32 bits access on the > + * interconnect. > + */ > + smmu->features &= ~(ARM_SMMU_FEAT_FMT_AARCH64_4K | > + ARM_SMMU_FEAT_FMT_AARCH64_16K | > + ARM_SMMU_FEAT_FMT_AARCH64_64K); > + > + return 0; > +} > + > +static const struct arm_smmu_impl mrvl_mmu500_impl = { > + .read_reg64 = mrvl_mmu500_readq, > + .write_reg64 = mrvl_mmu500_writeq, > + .cfg_probe = mrvl_mmu500_cfg_probe, > + .reset = arm_mmu500_reset, > +}; > + > > struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu) > { > @@ -175,5 +217,8 @@ struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu) > of_device_is_compatible(np, "qcom,sc7180-smmu-500")) > return qcom_smmu_impl_init(smmu); > > + if (of_device_is_compatible(np, "marvell,ap806-smmu-500")) > + smmu->impl = &mrvl_mmu500_impl; > + > return smmu; > } >
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