github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-23 14:42:08 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

iommu/arm-smmu-qcom: Enable threaded IRQ for Adreno SMMUv2/MMU500

Browse Source 
The recommended flow for stall-on-fault in SMMUv2 is the following:

1. Resolve the fault.
2. Write to FSR to clear the fault bits.
3. Write RESUME to retry or fail the transaction.

MMU500 is designed with this sequence in mind. For example,
experimentally we have seen on MMU500 that writing RESUME does not clear
FSR.SS unless the original fault is cleared in FSR, so 2 must come
before 3. FSR.SS is allowed to signal a fault (and does on MMU500) so
that if we try to do 2 -> 1 -> 3 (while exiting from the fault handler
after 2) we can get duplicate faults without hacks to disable
interrupts.

However, resolving the fault typically requires lengthy operations that
can stall, like bringing in pages from disk. The only current user,
drm/msm, dumps GPU state before failing the transaction which indeed can
stall. Therefore, from now on we will require implementations that want
to use stall-on-fault to also enable threaded IRQs. Do that with the
Adreno MMU implementations.

Signed-off-by: Connor Abbott <cwabbott0@gmail.com>
Link: https://lore.kernel.org/r/20250520-msm-gpu-fault-fixes-next-v8-1-fce6ee218787@gmail.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Connor Abbott 2025-05-20 15:08:54 -04:00 committed by Will Deacon
parent 3318f7b5ce
commit 1650620774
1 changed files with 2 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
View File

@ -585,6 +585,7 @@ static const struct arm_smmu_impl qcom_adreno_smmu_v2_impl = {
.alloc_context_bank = qcom_adreno_smmu_alloc_context_bank,
.write_sctlr = qcom_adreno_smmu_write_sctlr,
.tlb_sync = qcom_smmu_tlb_sync,
.context_fault_needs_threaded_irq = true,
};
static const struct arm_smmu_impl qcom_adreno_smmu_500_impl = {
@ -594,6 +595,7 @@ static const struct arm_smmu_impl qcom_adreno_smmu_500_impl = {
.alloc_context_bank = qcom_adreno_smmu_alloc_context_bank,
.write_sctlr = qcom_adreno_smmu_write_sctlr,
.tlb_sync = qcom_smmu_tlb_sync,
.context_fault_needs_threaded_irq = true,
};
static struct arm_smmu_device *qcom_smmu_create(struct arm_smmu_device *smmu,