isa_get_irq() takes an ISADevice argument mostly to resolve
the ISA bus. Extract the bus logic to isa_bus_get_irq().

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 include/hw/isa/isa.h | 1 +
 hw/isa/isa-bus.c     | 9 +++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/hw/isa/isa.h b/include/hw/isa/isa.h
index ddaae89a853..fd8b84d8007 100644
--- a/include/hw/isa/isa.h
+++ b/include/hw/isa/isa.h
@@ -91,6 +91,7 @@ struct ISADevice {
 ISABus *isa_bus_new(DeviceState *dev, MemoryRegion *address_space,
                     MemoryRegion *address_space_io, Error **errp);
 void isa_bus_irqs(ISABus *bus, qemu_irq *irqs);
+qemu_irq isa_bus_get_irq(ISABus *bus, unsigned isairq);
 qemu_irq isa_get_irq(ISADevice *dev, unsigned isairq);
 void isa_init_irq(ISADevice *dev, qemu_irq *p, unsigned isairq);
 void isa_connect_gpio_out(ISADevice *isadev, int gpioirq, unsigned isairq);
diff --git a/hw/isa/isa-bus.c b/hw/isa/isa-bus.c
index 7820068e6e1..b946e6dc478 100644
--- a/hw/isa/isa-bus.c
+++ b/hw/isa/isa-bus.c
@@ -75,6 +75,12 @@ void isa_bus_irqs(ISABus *bus, qemu_irq *irqs)
     bus->irqs = irqs;
 }
 
+qemu_irq isa_bus_get_irq(ISABus *bus, unsigned isairq)
+{
+    assert(isairq < ISA_NUM_IRQS);
+    return bus->irqs[isairq];
+}
+
 /*
  * isa_get_irq() returns the corresponding qemu_irq entry for the i8259.
  *
@@ -84,8 +90,7 @@ void isa_bus_irqs(ISABus *bus, qemu_irq *irqs)
 qemu_irq isa_get_irq(ISADevice *dev, unsigned isairq)
 {
     assert(!dev || ISA_BUS(qdev_get_parent_bus(DEVICE(dev))) == isabus);
-    assert(isairq < ISA_NUM_IRQS);
-    return isabus->irqs[isairq];
+    return isa_bus_get_irq(isabus, isairq);
 }
 
 void isa_init_irq(ISADevice *dev, qemu_irq *p, unsigned isairq)
-- 
2.26.3