[PATCH 6.1 005/127] iommu/arm-smmu-v3: Work around MMU-600 erratum 1076982

Greg Kroah-Hartman
2023-08-09T10:52:42Z

From: Robin Murphy <robin.murphy@arm.com>

commit f322e8af35c7f23a8c08b595c38d6c855b2d836f upstream

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>
Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Documentation/arm64/silicon-errata.rst | 2 +
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 29 ++++++++++++++++++++++++++++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 6 +++++
3 files changed, 37 insertions(+)

--- a/Documentation/arm64/silicon-errata.rst
+++ b/Documentation/arm64/silicon-errata.rst
@@ -141,6 +141,8 @@ stable kernels.
+----------------+-----------------+-----------------+-----------------------------+
| ARM | MMU-500 | #841119,826419 | N/A |
+----------------+-----------------+-----------------+-----------------------------+
+| ARM | MMU-600 | #1076982 | N/A |
++----------------+-----------------+-----------------+-----------------------------+
+----------------+-----------------+-----------------+-----------------------------+
| Broadcom | Brahma-B53 | N/A | ARM64_ERRATUM_845719 |
+----------------+-----------------+-----------------+-----------------------------+
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -3410,6 +3410,33 @@ static int arm_smmu_device_reset(struct
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;
@@ -3615,6 +3642,8 @@ static int arm_smmu_device_hw_probe(stru

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;

--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -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)