From: Daniel Mentz <danielmentz@google.com>
To: iommu@lists.linux.dev
Cc: Nicolin Chen <nicolinc@nvidia.com>,
Robin Murphy <robin.murphy@arm.com>,
Daniel Mentz <danielmentz@google.com>
Subject: [PATCH] iommu/arm-smmu-v3: Skip prefetch cmd for MMU-600, MMU-700
Date: Mon, 13 May 2024 14:54:20 -0700 [thread overview]
Message-ID: <20240513215420.408374-1-danielmentz@google.com> (raw)
Arm CoreLink MMU-600 and MMU-700 both silently ignore the
CMD_PREFETCH_CONFIG command. Let's not waste cycles adding this command to
the command queue if it is ignored anyway.
Signed-off-by: Daniel Mentz <danielmentz@google.com>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index aa62f0ecd053..98f1c4b44ef3 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -3684,6 +3684,8 @@ static void arm_smmu_device_iidr_probe(struct arm_smmu_device *smmu)
case IIDR_IMPLEMENTER_ARM:
switch (productid) {
case IIDR_PRODUCTID_ARM_MMU_600:
+ /* MMU-600 silently ignores CMD_PREFETCH_CONFIG */
+ smmu->options |= ARM_SMMU_OPT_SKIP_PREFETCH;
/* Arm erratum 1076982 */
if (variant == 0 && revision <= 2)
smmu->features &= ~ARM_SMMU_FEAT_SEV;
@@ -3692,6 +3694,8 @@ static void arm_smmu_device_iidr_probe(struct arm_smmu_device *smmu)
smmu->features &= ~ARM_SMMU_FEAT_NESTING;
break;
case IIDR_PRODUCTID_ARM_MMU_700:
+ /* MMU-700 silently ignores CMD_PREFETCH_CONFIG */
+ smmu->options |= ARM_SMMU_OPT_SKIP_PREFETCH;
/* Arm erratum 2812531 */
smmu->features &= ~ARM_SMMU_FEAT_BTM;
smmu->options |= ARM_SMMU_OPT_CMDQ_FORCE_SYNC;
--
2.45.0.118.g7fe29c98d7-goog
next reply other threads:[~2024-05-13 21:54 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-13 21:54 Daniel Mentz [this message]
2024-05-15 15:29 ` [PATCH] iommu/arm-smmu-v3: Skip prefetch cmd for MMU-600, MMU-700 Robin Murphy
2024-05-21 17:49 ` Daniel Mentz
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