Commit 0dfe314c authored by Robin Murphy's avatar Robin Murphy Committed by Will Deacon
Browse files

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across with less risk of going out of date or confusing users.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: default avatarRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/dfa82171b5248ad7cf1f25592101a6eec36b8c9a.1728400877.git.robin.murphy@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 8cf0b939

drivers/iommu/arm/arm-smmu/arm-smmu-impl.c

+2 −2
Original line number Diff line number Diff line
@@ -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;