hw/core: Add interface to allocate and free a single IRQ

qemu_allocate_irq returns a single qemu_irq.
The interface allows to specify an interrupt number.

qemu_free_irq frees it.

Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/core/irq.c

@@ -68,13 +68,29 @@ qemu_irq *qemu_allocate_irqs(qemu_irq_handler handler, void *opaque, int n)
     return qemu_extend_irqs(NULL, 0, handler, opaque, n);
 }
 
+qemu_irq qemu_allocate_irq(qemu_irq_handler handler, void *opaque, int n)
+{
+    struct IRQState *irq;
+
+    irq = g_new(struct IRQState, 1);
+    irq->handler = handler;
+    irq->opaque = opaque;
+    irq->n = n;
+
+    return irq;
+}
 
 void qemu_free_irqs(qemu_irq *s)
 {
     g_free(s[0]);
     g_free(s);
 }
 
+void qemu_free_irq(qemu_irq irq)
+{
+    g_free(irq);
+}
+
 static void qemu_notirq(void *opaque, int line, int level)
 {
     struct IRQState *irq = opaque;

include/hw/irq.h

@@ -30,13 +30,20 @@ static inline void qemu_irq_pulse(qemu_irq irq)
  */
 qemu_irq *qemu_allocate_irqs(qemu_irq_handler handler, void *opaque, int n);
 
+/*
+ * Allocates a single IRQ. The irq is assigned with a handler, an opaque
+ * data and the interrupt number.
+ */
+qemu_irq qemu_allocate_irq(qemu_irq_handler handler, void *opaque, int n);
+
 /* Extends an Array of IRQs. Old IRQs have their handlers and opaque data
  * preserved. New IRQs are assigned the argument handler and opaque data.
  */
 qemu_irq *qemu_extend_irqs(qemu_irq *old, int n_old, qemu_irq_handler handler,
                                 void *opaque, int n);
 
 void qemu_free_irqs(qemu_irq *s);
+void qemu_free_irq(qemu_irq irq);
 
 /* Returns a new IRQ with opposite polarity.  */
 qemu_irq qemu_irq_invert(qemu_irq irq);