irqchip/ti-sci-inta: Add support for INTA directly connecting to GIC

Driver assumes that Interrupt parent to Interrupt Aggregator is always
Interrupt router. This is not true always and GIC can be a parent to
Interrupt Aggregator. Update the driver to detect the parent and request
the parent irqs accordingly.
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200806074826.24607-11-lokeshvutla@ti.com

drivers/irqchip/irq-ti-sci-inta.c

@@ -8,6 +8,7 @@
 
 #include <linux/err.h>
 #include <linux/io.h>
+#include <linux/irq.h>
 #include <linux/irqchip.h>
 #include <linux/irqdomain.h>
 #include <linux/interrupt.h>
@@ -130,6 +131,37 @@ static void ti_sci_inta_irq_handler(struct irq_desc *desc)
 	chained_irq_exit(irq_desc_get_chip(desc), desc);
 }
 
+/**
+ * ti_sci_inta_xlate_irq() - Translate hwirq to parent's hwirq.
+ * @inta:	IRQ domain corresponding to Interrupt Aggregator
+ * @irq:	Hardware irq corresponding to the above irq domain
+ *
+ * Return parent irq number if translation is available else -ENOENT.
+ */
+static int ti_sci_inta_xlate_irq(struct ti_sci_inta_irq_domain *inta,
+				 u16 vint_id)
+{
+	struct device_node *np = dev_of_node(&inta->pdev->dev);
+	u32 base, parent_base, size;
+	const __be32 *range;
+	int len;
+
+	range = of_get_property(np, "ti,interrupt-ranges", &len);
+	if (!range)
+		return vint_id;
+
+	for (len /= sizeof(*range); len >= 3; len -= 3) {
+		base = be32_to_cpu(*range++);
+		parent_base = be32_to_cpu(*range++);
+		size = be32_to_cpu(*range++);
+
+		if (base <= vint_id && vint_id < base + size)
+			return vint_id - base + parent_base;
+	}
+
+	return -ENOENT;
+}
+
 /**
  * ti_sci_inta_alloc_parent_irq() - Allocate parent irq to Interrupt aggregator
  * @domain:	IRQ domain corresponding to Interrupt Aggregator
@@ -141,30 +173,52 @@ static struct ti_sci_inta_vint_desc *ti_sci_inta_alloc_parent_irq(struct irq_dom
 	struct ti_sci_inta_irq_domain *inta = domain->host_data;
 	struct ti_sci_inta_vint_desc *vint_desc;
 	struct irq_fwspec parent_fwspec;
+	struct device_node *parent_node;
 	unsigned int parent_virq;
-	u16 vint_id;
+	u16 vint_id, p_hwirq;
+	int ret;
 
 	vint_id = ti_sci_get_free_resource(inta->vint);
 	if (vint_id == TI_SCI_RESOURCE_NULL)
 		return ERR_PTR(-EINVAL);
 
+	p_hwirq = ti_sci_inta_xlate_irq(inta, vint_id);
+	if (p_hwirq < 0) {
+		ret = p_hwirq;
+		goto free_vint;
+	}
+
 	vint_desc = kzalloc(sizeof(*vint_desc), GFP_KERNEL);
-	if (!vint_desc)
-		return ERR_PTR(-ENOMEM);
+	if (!vint_desc) {
+		ret = -ENOMEM;
+		goto free_vint;
+	}
 
 	vint_desc->domain = domain;
 	vint_desc->vint_id = vint_id;
 	INIT_LIST_HEAD(&vint_desc->list);
 
-	parent_fwspec.fwnode = of_node_to_fwnode(of_irq_find_parent(dev_of_node(&inta->pdev->dev)));
-	parent_fwspec.param_count = 2;
-	parent_fwspec.param[0] = inta->ti_sci_id;
-	parent_fwspec.param[1] = vint_desc->vint_id;
+	parent_node = of_irq_find_parent(dev_of_node(&inta->pdev->dev));
+	parent_fwspec.fwnode = of_node_to_fwnode(parent_node);
+
+	if (of_device_is_compatible(parent_node, "arm,gic-v3")) {
+		/* Parent is GIC */
+		parent_fwspec.param_count = 3;
+		parent_fwspec.param[0] = 0;
+		parent_fwspec.param[1] = p_hwirq - 32;
+		parent_fwspec.param[2] = IRQ_TYPE_LEVEL_HIGH;
+	} else {
+		/* Parent is Interrupt Router */
+		parent_fwspec.param_count = 1;
+		parent_fwspec.param[0] = p_hwirq;
+	}
 
 	parent_virq = irq_create_fwspec_mapping(&parent_fwspec);
 	if (parent_virq == 0) {
-		kfree(vint_desc);
-		return ERR_PTR(-EINVAL);
+		dev_err(&inta->pdev->dev, "Parent IRQ allocation failed\n");
+		ret = -EINVAL;
+		goto free_vint_desc;
+
 	}
 	vint_desc->parent_virq = parent_virq;
 
@@ -173,6 +227,11 @@ static struct ti_sci_inta_vint_desc *ti_sci_inta_alloc_parent_irq(struct irq_dom
 					 ti_sci_inta_irq_handler, vint_desc);
 
 	return vint_desc;
+free_vint_desc:
+	kfree(vint_desc);
+free_vint:
+	ti_sci_release_resource(inta->vint, vint_id);
+	return ERR_PTR(ret);
 }
 
 /**
@@ -555,15 +614,15 @@ static int ti_sci_inta_irq_domain_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	inta->vint = devm_ti_sci_get_of_resource(inta->sci, dev, inta->ti_sci_id,
-						 "ti,sci-rm-range-vint");
+	inta->vint = devm_ti_sci_get_resource(inta->sci, dev, inta->ti_sci_id,
+					      TI_SCI_RESASG_SUBTYPE_IA_VINT);
 	if (IS_ERR(inta->vint)) {
 		dev_err(dev, "VINT resource allocation failed\n");
 		return PTR_ERR(inta->vint);
 	}
 
-	inta->global_event = devm_ti_sci_get_of_resource(inta->sci, dev, inta->ti_sci_id,
-							 "ti,sci-rm-range-global-event");
+	inta->global_event = devm_ti_sci_get_resource(inta->sci, dev, inta->ti_sci_id,
+						      TI_SCI_RESASG_SUBTYPE_GLOBAL_EVENT_SEVT);
 	if (IS_ERR(inta->global_event)) {
 		dev_err(dev, "Global event resource allocation failed\n");
 		return PTR_ERR(inta->global_event);
@@ -594,6 +653,8 @@ static int ti_sci_inta_irq_domain_probe(struct platform_device *pdev)
 	INIT_LIST_HEAD(&inta->vint_list);
 	mutex_init(&inta->vint_mutex);
 
+	dev_info(dev, "Interrupt Aggregator domain %d created\n", pdev->id);
+
 	return 0;
 }