iommu: msm: allow CBs to report an error when faults

Some clients of IOMMU treats the CB fault as non-recoverable
and they may want to trap the fault for debug purpose. Provide
that provision via context bank DT property.

Change-Id: Icb9cb67ed3dac44e144fcd7bc85deca833bf941c
Signed-off-by: Chintan Pandya <cpandya@codeaurora.org>

Documentation/devicetree/bindings/iommu/msm_iommu_v1.txt

@@ -75,6 +75,8 @@ Optional properties:
   the same property except this is for IOMMU with LPAE support.
 - qcom,iommu-sid-mask : List of mask values to map the unique stream ids to
   the Stream Mapping Table entries.
+- qcom,report-error-on-fault : boolean indicating that when any fault
+  occurs in this context bank, an error will be sent to respective master
 
 Example:
 

drivers/iommu/msm_iommu-v1.c

@@ -672,6 +672,12 @@ static void __program_context(struct msm_iommu_drvdata *iommu_drvdata,
 	/* Enable context fault interrupt */
 	SET_CB_SCTLR_CFIE(cb_base, ctx, 1);
 
+	/* Enable context fault error report */
+	if (ctx_drvdata->report_error_on_fault) {
+		SET_CB_SCTLR_HUPCF(cb_base, ctx, 1);
+		SET_CB_SCTLR_CFRE(cb_base, ctx, 1);
+	}
+
 	if (iommu_drvdata->model != MMU_500) {
 		/* Redirect all cacheable requests to L2 slave port. */
 		SET_CB_ACTLR_BPRCISH(cb_base, ctx, 1);

drivers/iommu/msm_iommu_dev-v1.c

@@ -591,6 +591,10 @@ static int msm_iommu_ctx_parse_dt(struct platform_device *pdev,
 					&ctx_drvdata->name))
 		ctx_drvdata->name = dev_name(&pdev->dev);
 
+	ctx_drvdata->report_error_on_fault =
+		of_property_read_bool(pdev->dev.of_node,
+				"qcom,report-error-on-fault");
+
 	if (!of_get_property(pdev->dev.of_node, "qcom,iommu-ctx-sids", &nsid)) {
 		ret = -EINVAL;
 		goto out;

include/linux/qcom_iommu.h

@@ -181,6 +181,7 @@ void iommu_resume(const struct msm_iommu_drvdata *iommu_drvdata);
 			the secure environment, false otherwise
  * @asid		ASID used with this context.
  * @attach_count	Number of time this context has been attached.
+ * @report_error_on_fault - true if error is returned back to master
  *
  * A msm_iommu_ctx_drvdata holds the driver data for a single context bank
  * within each IOMMU hardware instance
@@ -198,6 +199,7 @@ struct msm_iommu_ctx_drvdata {
 	int attach_count;
 	u32 sid_mask[MAX_NUM_SMR];
 	unsigned int n_sid_mask;
+	bool report_error_on_fault;
 };
 
 enum dump_reg {