From: Rob Clark <robdclark@xxxxxxxxxxxx>
On mmu-500, stall-on-fault seems to stall all context banks, causing the
GMU to misbehave. So limit this feature to smmu-v2 for now.
This fixes an issue with an older mesa bug taking outo the system
because of GMU going off into the weeds.
What we _think_ is happening is that, if the GPU generates 1000's of
faults at ~once (which is something that GPUs can be good at), it can
result in a sufficient number of stalled translations preventing other
transactions from entering the same TBU.
Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
---
v2: Adds a modparam to override the default behavior, for debugging
GPU faults in cases which do not (or might not) cause lockup.
Also, rebased to not depend on Bibek's PRR support.
drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 6372f3e25c4b..3239bbf18514 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -16,6 +16,10 @@
#define QCOM_DUMMY_VAL -1
+static int enable_stall = -1;
+MODULE_PARM_DESC(enable_stall, "Enable stall on iova fault (1=on , 0=disable, -1=auto (default))");
+module_param(enable_stall, int, 0600);
+
static struct qcom_smmu *to_qcom_smmu(struct arm_smmu_device *smmu)
{
return container_of(smmu, struct qcom_smmu, smmu);
@@ -210,7 +214,9 @@ static bool qcom_adreno_can_do_ttbr1(struct arm_smmu_device *smmu)
static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
struct io_pgtable_cfg *pgtbl_cfg, struct device *dev)
{
+ const struct device_node *np = smmu_domain->smmu->dev->of_node;
struct adreno_smmu_priv *priv;
+ bool stall_enabled;
smmu_domain->cfg.flush_walk_prefer_tlbiasid = true;
@@ -237,8 +243,17 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
priv->get_ttbr1_cfg = qcom_adreno_smmu_get_ttbr1_cfg;
priv->set_ttbr0_cfg = qcom_adreno_smmu_set_ttbr0_cfg;
priv->get_fault_info = qcom_adreno_smmu_get_fault_info;
- priv->set_stall = qcom_adreno_smmu_set_stall;
- priv->resume_translation = qcom_adreno_smmu_resume_translation;
+
+ if (enable_stall < 0) {
+ stall_enabled = of_device_is_compatible(np, "qcom,smmu-v2");
+ } else {
+ stall_enabled = !!enable_stall;
+ }
+
+ if (stall_enabled) {
+ priv->set_stall = qcom_adreno_smmu_set_stall;
+ priv->resume_translation = qcom_adreno_smmu_resume_translation;
+ }
return 0;
}
--
2.47.1
