hw/mem: Stubbed out NPCM7xx Memory Controller model

This just implements the bare minimum to cause the boot block to skip
memory initialization.

Reviewed-by: Tyrone Ting <kfting@nuvoton.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Alexander Bulekov <alxndr@bu.edu>
Signed-off-by: Havard Skinnemoen <hskinnemoen@google.com>
Message-id: 20200911052101.2602693-10-hskinnemoen@google.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

include/hw/arm/npcm7xx.h

@@ -18,6 +18,7 @@
 
 #include "hw/boards.h"
 #include "hw/cpu/a9mpcore.h"
+#include "hw/mem/npcm7xx_mc.h"
 #include "hw/misc/npcm7xx_clk.h"
 #include "hw/misc/npcm7xx_gcr.h"
 #include "hw/nvram/npcm7xx_otp.h"
@@ -71,6 +72,7 @@ typedef struct NPCM7xxState {
     NPCM7xxTimerCtrlState tim[3];
     NPCM7xxOTPState     key_storage;
     NPCM7xxOTPState     fuse_array;
+    NPCM7xxMCState      mc;
 } NPCM7xxState;
 
 #define TYPE_NPCM7XX    "npcm7xx"

include/hw/mem/npcm7xx_mc.h

@@ -0,0 +1,36 @@
+/*
+ * Nuvoton NPCM7xx Memory Controller stub
+ *
+ * Copyright 2020 Google LLC
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+#ifndef NPCM7XX_MC_H
+#define NPCM7XX_MC_H
+
+#include "exec/memory.h"
+#include "hw/sysbus.h"
+
+/**
+ * struct NPCM7xxMCState - Device state for the memory controller.
+ * @parent: System bus device.
+ * @mmio: Memory region through which registers are accessed.
+ */
+typedef struct NPCM7xxMCState {
+    SysBusDevice parent;
+
+    MemoryRegion mmio;
+} NPCM7xxMCState;
+
+#define TYPE_NPCM7XX_MC "npcm7xx-mc"
+#define NPCM7XX_MC(obj) OBJECT_CHECK(NPCM7xxMCState, (obj), TYPE_NPCM7XX_MC)
+
+#endif /* NPCM7XX_MC_H */