iommu/arm-smmu-qcom-debug: Add support for TBUs

Operating the TBUs (Translation Buffer Units) from Linux on Qualcomm
platforms can help with debugging context faults. To help with that,
the TBUs can run ATOS (Address Translation Operations) to manually
trigger address translation of IOVA to physical address in hardware
and provide more details when a context fault happens.

The driver will control the resources needed by the TBU to allow
running the debug operations such as ATOS, check for outstanding
transactions, do snapshot capture etc.
Signed-off-by: Georgi Djakov <quic_c_gdjako@quicinc.com>
Link: https://lore.kernel.org/r/20240417133731.2055383-3-quic_c_gdjako@quicinc.comSigned-off-by: Will Deacon <will@kernel.org>

drivers/iommu/Kconfig

@@ -379,10 +379,14 @@ config ARM_SMMU_QCOM_DEBUG
 	depends on ARM_SMMU_QCOM
 	help
 	  Support for implementation specific debug features in ARM SMMU
-	  hardware found in QTI platforms.
-
-	  Say Y here to enable debug for issues such as TLB sync timeouts
-	  which requires implementation defined register dumps.
+	  hardware found in QTI platforms. This include support for
+	  the Translation Buffer Units (TBU) that can be used to obtain
+	  additional information when debugging memory management issues
+	  like context faults.
+
+	  Say Y here to enable debug for issues such as context faults
+	  or TLB sync timeouts which requires implementation defined
+	  register dumps.
 
 config ARM_SMMU_V3
 	tristate "ARM Ltd. System MMU Version 3 (SMMUv3) Support"

drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h

@@ -30,6 +30,8 @@ struct qcom_smmu_match_data {
 	const struct arm_smmu_impl *adreno_impl;
 };
 
+irqreturn_t qcom_smmu_context_fault(int irq, void *dev);
+
 #ifdef CONFIG_ARM_SMMU_QCOM_DEBUG
 void qcom_smmu_tlb_sync_debug(struct arm_smmu_device *smmu);
 #else

drivers/iommu/arm/arm-smmu/arm-smmu.h

@@ -136,6 +136,7 @@ enum arm_smmu_cbar_type {
 #define ARM_SMMU_CBAR_VMID		GENMASK(7, 0)
 
 #define ARM_SMMU_GR1_CBFRSYNRA(n)	(0x400 + ((n) << 2))
+#define ARM_SMMU_CBFRSYNRA_SID		GENMASK(15, 0)
 
 #define ARM_SMMU_GR1_CBA2R(n)		(0x800 + ((n) << 2))
 #define ARM_SMMU_CBA2R_VMID16		GENMASK(31, 16)
@@ -238,6 +239,7 @@ enum arm_smmu_cbar_type {
 #define ARM_SMMU_CB_ATSR		0x8f0
 #define ARM_SMMU_ATSR_ACTIVE		BIT(0)
 
+#define ARM_SMMU_RESUME_TERMINATE	BIT(0)
 
 /* Maximum number of context banks per SMMU */
 #define ARM_SMMU_MAX_CBS		128