This adds the downstream property required to support
SMMUs on SDM630 and other platforms (the need for it
most likely depends on firmware configuration).
Signed-off-by: Konrad Dybcio <konradybcio@xxxxxxxxx>
---
.../devicetree/bindings/iommu/arm,smmu.yaml | 10 ++++++++++
drivers/iommu/arm-smmu.c | 15 +++++++++------
2 files changed, 19 insertions(+), 6 deletions(-)
diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
index d7ceb4c34423..9abd6d41a32c 100644
--- a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
+++ b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
@@ -102,6 +102,16 @@ properties:
access to SMMU configuration registers. In this case non-secure aliases of
secure registers have to be used during SMMU configuration.
+ qcom,skip-init:
+ description: |
+ Disable resetting configuration for all context banks
+ during device reset. This is useful for targets where
+ some context banks are dedicated to other execution
+ environments outside of Linux and those other EEs are
+ programming their own stream match tables, SCTLR, etc.
+ Without setting this option we will trample on their
+ configuration.
+
stream-match-mask:
$ref: /schemas/types.yaml#/definitions/uint32
description: |
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 243bc4cb2705..a5c623d4caf9 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1655,13 +1655,16 @@ static void arm_smmu_device_reset(struct arm_smmu_device *smmu)
* Reset stream mapping groups: Initial values mark all SMRn as
* invalid and all S2CRn as bypass unless overridden.
*/
- for (i = 0; i < smmu->num_mapping_groups; ++i)
- arm_smmu_write_sme(smmu, i);
- /* Make sure all context banks are disabled and clear CB_FSR */
- for (i = 0; i < smmu->num_context_banks; ++i) {
- arm_smmu_write_context_bank(smmu, i);
- arm_smmu_cb_write(smmu, i, ARM_SMMU_CB_FSR, ARM_SMMU_FSR_FAULT);
+ if (!of_find_property(smmu->dev->of_node, "qcom,skip-init", NULL)) {
+ for (i = 0; i < smmu->num_mapping_groups; ++i)
+ arm_smmu_write_sme(smmu, i);
+
+ /* Make sure all context banks are disabled and clear CB_FSR */
+ for (i = 0; i < smmu->num_context_banks; ++i) {
+ arm_smmu_write_context_bank(smmu, i);
+ arm_smmu_cb_write(smmu, i, ARM_SMMU_CB_FSR, ARM_SMMU_FSR_FAULT);
+ }
}
/* Invalidate the TLB, just in case */
--
2.27.0
