Introduce PortioList

Add a type and methods for manipulating a list of disjoint I/O ports,
used in some older hardware devices.

Based on original patch by Richard Henderson.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/ioport.h b/ioport.h
index 82ffd9d..ae3e9da 100644
--- a/ioport.h
+++ b/ioport.h
@@ -52,4 +52,25 @@
 uint16_t cpu_inw(pio_addr_t addr);
 uint32_t cpu_inl(pio_addr_t addr);
 
+struct MemoryRegion;
+struct MemoryRegionPortio;
+
+typedef struct PortioList {
+    const struct MemoryRegionPortio *ports;
+    struct MemoryRegion *address_space;
+    unsigned nr;
+    struct MemoryRegion **regions;
+    void *opaque;
+    const char *name;
+} PortioList;
+
+void portio_list_init(PortioList *piolist,
+                      const struct MemoryRegionPortio *callbacks,
+                      void *opaque, const char *name);
+void portio_list_destroy(PortioList *piolist);
+void portio_list_add(PortioList *piolist,
+                     struct MemoryRegion *address_space,
+                     uint32_t addr);
+void portio_list_del(PortioList *piolist);
+
 #endif /* IOPORT_H */