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iommu/arm-smmu-v3: Work around MMU-600 erratum 1076982 

MMU-600 versions prior to r1p0 fail to correctly generate a WFE wakeup
event when the command queue transitions fom full to non-full. We can
easily work around this by simply hiding the SEV capability such that we
fall back to polling for space in the queue - since MMU-600 implements
MSIs we wouldn't expect to need SEV for sync completion either, so this
should have little to no impact.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Link: https://lore.kernel.org/r/08adbe3d01024d8382a478325f73b56851f76e49.1683731256.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Robin Murphy 2023-05-10 16:38:43 +01:00 committed by Will Deacon
parent 44c026a73b
commit f322e8af35
3 changed files with 37 additions and 0 deletions
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2
Documentation/arm64/silicon-errata.rst
View File

@ -140,6 +140,8 @@ stable kernels.
+----------------+-----------------+-----------------+-----------------------------+
| ARM | MMU-500 | #841119,826419 | N/A |
+----------------+-----------------+-----------------+-----------------------------+
| ARM | MMU-600 | #1076982 | N/A |
+----------------+-----------------+-----------------+-----------------------------+
+----------------+-----------------+-----------------+-----------------------------+
| Broadcom | Brahma-B53 | N/A | ARM64_ERRATUM_845719 |
+----------------+-----------------+-----------------+-----------------------------+

29
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
View File

@ -3429,6 +3429,33 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
return 0;
}
#define IIDR_IMPLEMENTER_ARM 0x43b
#define IIDR_PRODUCTID_ARM_MMU_600 0x483
static void arm_smmu_device_iidr_probe(struct arm_smmu_device *smmu)
{
u32 reg;
unsigned int implementer, productid, variant, revision;
reg = readl_relaxed(smmu->base + ARM_SMMU_IIDR);
implementer = FIELD_GET(IIDR_IMPLEMENTER, reg);
productid = FIELD_GET(IIDR_PRODUCTID, reg);
variant = FIELD_GET(IIDR_VARIANT, reg);
revision = FIELD_GET(IIDR_REVISION, reg);
switch (implementer) {
case IIDR_IMPLEMENTER_ARM:
switch (productid) {
case IIDR_PRODUCTID_ARM_MMU_600:
/* Arm erratum 1076982 */
if (variant == 0 && revision <= 2)
smmu->features &= ~ARM_SMMU_FEAT_SEV;
break;
}
break;
}
}
static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
{
u32 reg;
@ -3635,6 +3662,8 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
smmu->ias = max(smmu->ias, smmu->oas);
arm_smmu_device_iidr_probe(smmu);
if (arm_smmu_sva_supported(smmu))
smmu->features |= ARM_SMMU_FEAT_SVA;

6
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
View File

@ -69,6 +69,12 @@
#define IDR5_VAX GENMASK(11, 10)
#define IDR5_VAX_52_BIT 1
#define ARM_SMMU_IIDR 0x18
#define IIDR_PRODUCTID GENMASK(31, 20)
#define IIDR_VARIANT GENMASK(19, 16)
#define IIDR_REVISION GENMASK(15, 12)
#define IIDR_IMPLEMENTER GENMASK(11, 0)
#define ARM_SMMU_CR0 0x20
#define CR0_ATSCHK (1 << 4)
#define CR0_CMDQEN (1 << 3)