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>

arch/sandbox/dts/test.dts

@@ -522,6 +522,9 @@
 	};
 
 	f-test {
+		#interrupt-cells = <2>;
+		interrupt-parent = <&irq>;
+		interrupts = <4 0>;
 		compatible = "denx,u-boot-fdt-test";
 	};
 

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);

include/irq.h

@@ -200,6 +200,20 @@ int irq_restore_polarities(struct udevice *dev);
  */
 int irq_read_and_clear(struct irq *irq);
 
+/**
+ * irq_get_interrupt_parent() - returns the interrupt parent
+ *
+ * Walks the devicetree and returns the interrupt parent's ofnode
+ * for the specified device.
+ *
+ * @dev: device
+ * @interrupt_parent: The interrupt parent's ofnode'
+ * Return: 0 success, or error value
+ *
+ */
+int irq_get_interrupt_parent(const struct udevice *dev,
+			     struct udevice **interrupt_parent);
+
 struct phandle_2_arg;
 /**
  * irq_get_by_phandle() - Get an irq by its phandle information (of-platadata)

test/dm/irq.c

@@ -76,6 +76,21 @@ static int dm_test_request(struct unit_test_state *uts)
 }
 DM_TEST(dm_test_request, UTF_SCAN_PDATA | UTF_SCAN_FDT);
 
+/* Test of irq_get_by_index() */
+static int dm_test_irq_get_by_index(struct unit_test_state *uts)
+{
+	struct udevice *dev;
+	struct irq irq;
+
+	ut_assertok(uclass_get_device_by_name(UCLASS_TEST_FDT, "f-test",
+					      &dev));
+	ut_assertok(irq_get_by_index(dev, 0, &irq));
+	ut_asserteq(4, irq.id);
+
+	return 0;
+}
+DM_TEST(dm_test_irq_get_by_index, UTF_SCAN_PDATA | UTF_SCAN_FDT);
+
 /* Test of irq_get_acpi() */
 static int dm_test_irq_get_acpi(struct unit_test_state *uts)
 {