From: Robin Murphy Date: Tue, 8 Oct 2024 15:21:17 +0000 (+0100) Subject: iommu/arm-smmu: Clarify MMU-500 CPRE workaround X-Git-Tag: v6.12-rc4~28^2~1^2~2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0dfe314cdd0d378f96bb9c6bdc05c8120f48606d;p=thirdparty%2Flinux.git iommu/arm-smmu: Clarify MMU-500 CPRE workaround CPRE workarounds are implicated in at least 5 MMU-500 errata, some of which remain unfixed. The comment and warning message have proven to be unhelpfully misleading about this scope, so reword them to get the point across with less risk of going out of date or confusing users. Signed-off-by: Robin Murphy Link: https://lore.kernel.org/r/dfa82171b5248ad7cf1f25592101a6eec36b8c9a.1728400877.git.robin.murphy@arm.com Signed-off-by: Will Deacon --- diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c b/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c index 9dc772f2cbb27..99030e6b16e7a 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c @@ -130,7 +130,7 @@ int arm_mmu500_reset(struct arm_smmu_device *smmu) /* * Disable MMU-500's not-particularly-beneficial next-page - * prefetcher for the sake of errata #841119 and #826419. + * prefetcher for the sake of at least 5 known errata. */ for (i = 0; i < smmu->num_context_banks; ++i) { reg = arm_smmu_cb_read(smmu, i, ARM_SMMU_CB_ACTLR); @@ -138,7 +138,7 @@ int arm_mmu500_reset(struct arm_smmu_device *smmu) arm_smmu_cb_write(smmu, i, ARM_SMMU_CB_ACTLR, reg); reg = arm_smmu_cb_read(smmu, i, ARM_SMMU_CB_ACTLR); if (reg & ARM_MMU500_ACTLR_CPRE) - dev_warn_once(smmu->dev, "Failed to disable prefetcher [errata #841119 and #826419], check ACR.CACHE_LOCK\n"); + dev_warn_once(smmu->dev, "Failed to disable prefetcher for errata workarounds, check SACR.CACHE_LOCK\n"); } return 0;