msm: camera: smmu: Populate fault properties for CBs

Populate fault properties for all the context banks from the
device tree. If the CB has marked faults as non-fatal, return
success to iommu fault handler. This will avoid SMMU from
further logging debug info, and retrying the faulted transaction
again with any different settings, which could potentially
lead to further fault IRQs being triggered.

CRs-Fixed: 3175797
Change-Id: I5624c77bc4205ee916618e32c7595bc5e886502a
Signed-off-by: Karthik Anantha Ram <[email protected]>

drivers/cam_smmu/cam_smmu_api.c

@@ -138,6 +138,8 @@ struct cam_context_bank_info {
 	bool is_secheap_allocated;
 	bool is_fwuncached_buf_allocated;
 	bool is_qdss_allocated;
+	bool non_fatal_faults_en;
+	bool stall_disable_en;
 
 	struct scratch_mapping scratch_map;
 	struct gen_pool *shared_mem_pool;
@@ -898,6 +900,19 @@ static int cam_smmu_iommu_fault_handler(struct iommu_domain *domain,
 
 	cam_smmu_page_fault_work(&iommu_cb_set.smmu_work);
 
+	/*
+	 * If cb has faults marked as non fatal, return handled to SMMU
+	 * This will skip printing any debug info from SMMU, which is also available as
+	 * part of fault handler cb. This will avoid any transaction retries which could
+	 * lead to further fault irqs being triggered
+	 */
+	if (iommu_cb_set.cb_info[idx].non_fatal_faults_en) {
+		CAM_DBG(CAM_SMMU,
+			"PF marked as non-fatal for cb: %s, return success to SMMU",
+			cb_name);
+		return 0;
+	}
+
 	return -ENOSYS;
 }
 
@@ -4200,13 +4215,24 @@ static int cam_smmu_get_memory_regions_info(struct device_node *of_node,
 	return rc;
 }
 
+static void cam_smmu_check_for_fault_properties(
+	const char *fault_property, struct cam_context_bank_info *cb)
+{
+	if (!strcmp(fault_property, "non-fatal"))
+		cb->non_fatal_faults_en = true;
+	else if (!strcmp(fault_property, "stall-disable"))
+		cb->stall_disable_en = true;
+
+	CAM_DBG(CAM_SMMU, "iommu fault property: %s found for cb: %s",
+		fault_property, cb->name[0]);
+}
+
 static int cam_populate_smmu_context_banks(struct device *dev,
 	enum cam_iommu_type type)
 {
-	int rc = 0;
+	int rc = 0, i, num_fault_props = 0;
 	struct cam_context_bank_info *cb;
 	struct device *ctx = NULL;
-	int i = 0;
 	bool dma_coherent, dma_coherent_hint;
 
 	if (!dev) {
@@ -4299,11 +4325,26 @@ static int cam_populate_smmu_context_banks(struct device *dev,
 			cb->name[0]);
 		goto cb_init_fail;
 	}
-	if (cb->io_support && cb->domain)
+	if (cb->io_support && cb->domain) {
 		iommu_set_fault_handler(cb->domain,
 			cam_smmu_iommu_fault_handler,
 			(void *)cb->name[0]);
 
+		num_fault_props = of_property_count_strings(dev->of_node, "qcom,iommu-faults");
+		if (num_fault_props > 0) {
+			const char *fault_property = NULL;
+
+			for (i = 0; i < num_fault_props; i++) {
+				rc = of_property_read_string_index(dev->of_node,
+					"qcom,iommu-faults", i, &fault_property);
+				if (!rc)
+					cam_smmu_check_for_fault_properties(fault_property, cb);
+			}
+			/* Missing fault property reads is not an error */
+			rc = 0;
+		}
+	}
+
 	if (!dev->dma_parms)
 		dev->dma_parms = devm_kzalloc(dev,
 			sizeof(*dev->dma_parms), GFP_KERNEL);