hw/char/mchp_pfsoc_mmuart: QOM'ify PolarFire MMUART

- Embed SerialMM in MchpPfSoCMMUartState and QOM-initialize it
- Alias SERIAL_MM 'chardev' property on MCHP_PFSOC_UART
- Forward SerialMM sysbus IRQ in mchp_pfsoc_mmuart_realize()
- Add DeviceReset() method
- Add vmstate structure for migration
- Register device in 'input' category
- Keep mchp_pfsoc_mmuart_create() behavior

Note, serial_mm_init() calls qdev_set_legacy_instance_id().
This call is only needed for backwards-compatibility of incoming
migration data with old versions of QEMU which implemented migration
of devices with hand-rolled code. Since this device didn't previously
handle migration at all, then it doesn't need to set the legacy
instance ID.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Bin Meng <bin.meng@windriver.com>
Tested-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20210925133407.1259392-4-f4bug@amsat.org
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

include/hw/char/mchp_pfsoc_mmuart.h

@@ -28,17 +28,23 @@
 #ifndef HW_MCHP_PFSOC_MMUART_H
 #define HW_MCHP_PFSOC_MMUART_H
 
+#include "hw/sysbus.h"
 #include "hw/char/serial.h"
 
 #define MCHP_PFSOC_MMUART_REG_COUNT 13
 
+#define TYPE_MCHP_PFSOC_UART "mchp.pfsoc.uart"
+OBJECT_DECLARE_SIMPLE_TYPE(MchpPfSoCMMUartState, MCHP_PFSOC_UART)
+
 typedef struct MchpPfSoCMMUartState {
+    /*< private >*/
+    SysBusDevice parent_obj;
+
+    /*< public >*/
     MemoryRegion container;
     MemoryRegion iomem;
-    hwaddr base;
-    qemu_irq irq;
 
-    SerialMM *serial;
+    SerialMM serial_mm;
 
     uint32_t reg[MCHP_PFSOC_MMUART_REG_COUNT];
 } MchpPfSoCMMUartState;