Thread (8 messages) flat view 8 messages, 4 authors, 2025-07-14
STALE436d LANDED

Landed in mainline as b9bb7e814cd0 on 2025-07-14.

[PATCH v2] iommu/arm-smmu: disable PRR on SM8250

From: Dmitry Baryshkov <hidden>
Date: 2025-07-05 16:08:40
Also in: linux-arm-msm, linux-iommu, lkml
Subsystem: arm smmu drivers, iommu subsystem, qualcomm iommu, the rest · Maintainers: Will Deacon, Joerg Roedel, Rob Clark, Linus Torvalds

On SM8250 / QRB5165-RB5 using PRR bits resets the device, most likely
because of the hyp limitations. Disable PRR support on that platform.

Fixes: 7f2ef1bfc758 ("iommu/arm-smmu: Add support for PRR bit setup")
Signed-off-by: Dmitry Baryshkov <redacted>
---
I currently don't have access to other devices from these generations.
It might be necessary to apply the same workaround to other platforms.
---
Changes in v2:
- Simplify the workaround as the issue seems to be limited to SM8250
  only (Rob)
- Link to v1: https://lore.kernel.org/r/20250705-iommu-fix-prr-v1-1-ef725033651c@oss.qualcomm.com (local)
---
 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 62874b18f6459ad9a8b0542ab81c24e3e745c53d..53d88646476e9f193a6275d9c3ee3d084c215362 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -355,7 +355,8 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
 	priv->set_prr_addr = NULL;
 
 	if (of_device_is_compatible(np, "qcom,smmu-500") &&
-			of_device_is_compatible(np, "qcom,adreno-smmu")) {
+	    !of_device_is_compatible(np, "qcom,sm8250-smmu-500") &&
+	    of_device_is_compatible(np, "qcom,adreno-smmu")) {
 		priv->set_prr_bit = qcom_adreno_smmu_set_prr_bit;
 		priv->set_prr_addr = qcom_adreno_smmu_set_prr_addr;
 	}
---
base-commit: 7244e36657076b597ac21d118be9c0b0f15fc622
change-id: 20250705-iommu-fix-prr-600451b1d304

Best regards,
-- 
With best wishes
Dmitry

Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help