And move the "it_shift" field there, since it's specific.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/char/serial.c         | 10 ++++++----
 include/hw/char/serial.h |  9 +++++++--
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/hw/char/serial.c b/hw/char/serial.c
index b623c4e79f..4fc2bcedf1 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -1025,14 +1025,14 @@ static const TypeInfo serial_info = {
 static uint64_t serial_mm_read(void *opaque, hwaddr addr,
                                unsigned size)
 {
-    SerialState *s = opaque;
+    SerialMMState *s = SERIAL_MM(opaque);
     return serial_ioport_read(s, addr >> s->it_shift, 1);
 }
 
 static void serial_mm_write(void *opaque, hwaddr addr,
                             uint64_t value, unsigned size)
 {
-    SerialState *s = opaque;
+    SerialMMState *s = SERIAL_MM(opaque);
     value &= 255;
     serial_ioport_write(s, addr >> s->it_shift, value, 1);
 }
@@ -1066,10 +1066,11 @@ SerialState *serial_mm_init(MemoryRegion *address_space,
                             qemu_irq irq, int baudbase,
                             Chardev *chr, enum device_endian end)
 {
-    DeviceState *dev = DEVICE(object_new(TYPE_SERIAL));
+    DeviceState *dev = DEVICE(object_new(TYPE_SERIAL_MM));
+    SerialMMState *m = SERIAL_MM(dev);
     SerialState *s = SERIAL(dev);
 
-    s->it_shift = it_shift;
+    m->it_shift = it_shift;
     s->irq = irq;
     s->baudbase = baudbase;
     qdev_prop_set_chr(dev, "chardev", chr);
@@ -1088,6 +1089,7 @@ SerialState *serial_mm_init(MemoryRegion *address_space,
 static const TypeInfo serial_mm_info = {
     .name = TYPE_SERIAL_MM,
     .parent = TYPE_SERIAL,
+    .instance_size = sizeof(SerialMMState),
 };
 
 static void serial_register_types(void)
diff --git a/include/hw/char/serial.h b/include/hw/char/serial.h
index 2b8dbd88f1..62962e3c5a 100644
--- a/include/hw/char/serial.h
+++ b/include/hw/char/serial.h
@@ -57,7 +57,6 @@ typedef struct SerialState {
     qemu_irq irq;
     CharBackend chr;
     int last_break_enable;
-    int it_shift;
     int baudbase;
     uint32_t tsr_retry;
     guint watch_tag;
@@ -80,6 +79,12 @@ typedef struct SerialState {
     MemoryRegion io;
 } SerialState;
 
+typedef struct SerialMMState {
+    SerialState parent;
+
+    int it_shift;
+} SerialMMState;
+
 extern const VMStateDescription vmstate_serial;
 extern const MemoryRegionOps serial_io_ops;
 
@@ -91,7 +96,7 @@ void serial_set_frequency(SerialState *s, uint32_t frequency);
 #define SERIAL(s) OBJECT_CHECK(SerialState, (s), TYPE_SERIAL)
 
 #define TYPE_SERIAL_MM "serial-mm"
-#define SERIAL_MM(s) OBJECT_CHECK(SerialState, (s), TYPE_SERIAL_MM)
+#define SERIAL_MM(s) OBJECT_CHECK(SerialMMState, (s), TYPE_SERIAL_MM)
 
 SerialState *serial_init(int base, qemu_irq irq, int baudbase,
                          Chardev *chr, MemoryRegion *system_io);
-- 
2.23.0.606.g08da6496b6