diff options
| author | Jean-Philippe Brucker <jean-philippe@linaro.org> | 2023-03-21 10:06:00 +0000 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2023-03-27 13:22:23 +0100 |
| commit | 8c153645fa402ee96ec3c2fef9db3a087b3667ac (patch) | |
| tree | 42f9d6c28efa5e9291d00688bc570c32b6b777d7 /drivers/iommu/arm/arm-smmu-v3 | |
| parent | e8d018dd0257f744ca50a729e3d042cf2ec9da65 (diff) | |
iommu/arm-smmu-v3: Explain why ATS stays disabled with bypass
The SMMU does not support enabling ATS for a bypass stream. Add a comment.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20230321100559.341981-1-jean-philippe@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'drivers/iommu/arm/arm-smmu-v3')
| -rw-r--r-- | drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 7 |
1 files changed, 7 insertions, 0 deletions
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 f2425b0f0cd6..a8410c132f1e 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -2447,6 +2447,13 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) master->domain = smmu_domain; + /* + * The SMMU does not support enabling ATS with bypass. When the STE is + * in bypass (STE.Config[2:0] == 0b100), ATS Translation Requests and + * Translated transactions are denied as though ATS is disabled for the + * stream (STE.EATS == 0b00), causing F_BAD_ATS_TREQ and + * F_TRANSL_FORBIDDEN events (IHI0070Ea 5.2 Stream Table Entry). + */ if (smmu_domain->stage != ARM_SMMU_DOMAIN_BYPASS) master->ats_enabled = arm_smmu_ats_supported(master); |