drivers: misc: irq-uclass: Update irq_get_by_index

Support reading the "interrupts" property from the devicetree in case
the "interrupts-extended" property isn't found. As the "interrupts"
property is commonly used, this allows to parse all existing FDT and
makes irq_get_by_index() more useful.

The "interrupts" property doesn't contain a phandle as "interrupts-extended"
does, so implement a new method to locate the interrupt-parent called
irq_get_interrupt_parent().

TEST: Read the interrupts from the GIC node for ACPI MADT generation.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-by: Moritz Fischer <moritzf@google.com>

1 files changed, 65 insertions, 1 deletions

diff --git a/drivers/misc/irq-uclass.c b/drivers/misc/irq-uclass.c
index 79eb7c200dc..ac778593c96 100644
--- a/drivers/misc/irq-uclass.c
+++ b/drivers/misc/irq-uclass.c
@@ -62,6 +62,40 @@ int irq_read_and_clear(struct irq *irq)
 	return ops->read_and_clear(irq);
 }
 
+int irq_get_interrupt_parent(const struct udevice *dev,
+			     struct udevice **interrupt_parent)
+{
+	struct ofnode_phandle_args phandle_args;
+	struct udevice *irq = NULL;
+	ofnode node;
+	int ret;
+
+	if (!dev || !interrupt_parent)
+		return -EINVAL;
+
+	*interrupt_parent = NULL;
+
+	node = dev_ofnode(dev);
+	if (!ofnode_valid(node))
+		return -EINVAL;
+
+	while (ofnode_valid(node)) {
+		ret = ofnode_parse_phandle_with_args(node, "interrupt-parent",
+						     NULL, 0, 0, &phandle_args);
+		if (!ret && !device_get_global_by_ofnode(phandle_args.node, &irq))
+			break;
+		node = ofnode_get_parent(node);
+	}
+
+	if (!irq) {
+		log_err("Cannot find an interrupt parent for device %s\n", dev->name);
+		return -ENODEV;
+	}
+	*interrupt_parent = irq;
+
+	return 0;
+}
+
 #if CONFIG_IS_ENABLED(OF_PLATDATA)
 int irq_get_by_phandle(struct udevice *dev, const struct phandle_2_arg *cells,
 		       struct irq *irq)
@@ -142,10 +176,40 @@ err:
 int irq_get_by_index(struct udevice *dev, int index, struct irq *irq)
 {
 	struct ofnode_phandle_args args;
-	int ret;
+	struct udevice *interrupt_parent;
+	int ret, size, i;
+	const __be32 *list;
+	u32 count;
 
 	ret = dev_read_phandle_with_args(dev, "interrupts-extended",
 					 "#interrupt-cells", 0, index, &args);
+	if (ret) {
+		list = dev_read_prop(dev, "interrupts", &size);
+		if (!list)
+			return -ENOENT;
+
+		ret = irq_get_interrupt_parent(dev, &interrupt_parent);
+		if (ret)
+			return -ENODEV;
+		args.node = dev_ofnode(interrupt_parent);
+
+		if (dev_read_u32(interrupt_parent, "#interrupt-cells", &count)) {
+			log_err("%s: could not get #interrupt-cells for %s\n",
+				__func__, dev->name);
+			return -ENOENT;
+		}
+
+		if (index * count >= size / sizeof(*list))
+			return -ENOENT;
+		if (count > OF_MAX_PHANDLE_ARGS)
+			count = OF_MAX_PHANDLE_ARGS;
+		args.args_count = count;
+		for (i = 0; i < count; i++)
+			args.args[i] = be32_to_cpup(&list[index * count + i]);
+
+		return irq_get_by_index_tail(ret, dev_ofnode(dev), &args,
+					     "interrupts", index, irq);
+	}
 
 	return irq_get_by_index_tail(ret, dev_ofnode(dev), &args,
 				     "interrupts-extended", index > 0, irq);