sysbus: Expose IRQ enumeration helpers

Sysbus devices can get their IRQ lines connected to other devices. It is
possible to figure out which IRQ line a connection is on and whether a sysbus
device even provides an IRQ connector at a specific offset.

This patch exposes helpers to make this information publicly accessible. We
will need it for the platform bus dynamic sysbus enumeration.

Signed-off-by: Alexander Graf <agraf@suse.de>

2 files changed, 32 insertions, 0 deletions

diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index b3d519645a..413b41376f 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -453,6 +453,17 @@ void qdev_connect_gpio_out_named(DeviceState *dev, const char *name, int n,
     g_free(propname);
 }
 
+qemu_irq qdev_get_gpio_out_connector(DeviceState *dev, const char *name, int n)
+{
+    char *propname = g_strdup_printf("%s[%d]",
+                                     name ? name : "unnamed-gpio-out", n);
+
+    qemu_irq ret = (qemu_irq)object_property_get_link(OBJECT(dev), propname,
+                                                      NULL);
+
+    return ret;
+}
+
 /* disconnect a GPIO ouput, returning the disconnected input (if any) */
 
 static qemu_irq qdev_disconnect_gpio_out_named(DeviceState *dev,
diff --git a/hw/core/sysbus.c b/hw/core/sysbus.c
index 7bfe381cd8..945dec53d0 100644
--- a/hw/core/sysbus.c
+++ b/hw/core/sysbus.c
@@ -84,6 +84,27 @@ static const TypeInfo system_bus_info = {
     .class_init = system_bus_class_init,
 };
 
+/* Check whether an IRQ source exists */
+bool sysbus_has_irq(SysBusDevice *dev, int n)
+{
+    char *prop = g_strdup_printf("%s[%d]", SYSBUS_DEVICE_GPIO_IRQ, n);
+    ObjectProperty *r;
+
+    r = object_property_find(OBJECT(dev), prop, NULL);
+    return (r != NULL);
+}
+
+bool sysbus_is_irq_connected(SysBusDevice *dev, int n)
+{
+    return !!sysbus_get_connected_irq(dev, n);
+}
+
+qemu_irq sysbus_get_connected_irq(SysBusDevice *dev, int n)
+{
+    DeviceState *d = DEVICE(dev);
+    return qdev_get_gpio_out_connector(d, SYSBUS_DEVICE_GPIO_IRQ, n);
+}
+
 void sysbus_connect_irq(SysBusDevice *dev, int n, qemu_irq irq)
 {
     qdev_connect_gpio_out_named(DEVICE(dev), SYSBUS_DEVICE_GPIO_IRQ, n, irq);