hw/fsi: Introduce IBM's FSI master

This is a part of patchset where IBM's Flexible Service Interface is
introduced.

This commit models the FSI master. CFAM is hanging out of FSI master which is a bus controller.

The FSI master: A controller in the platform service processor (e.g.
BMC) driving CFAM engine accesses into the POWER chip. At the
hardware level FSI is a bit-based protocol supporting synchronous and
DMA-driven accesses of engines in a CFAM.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Ninad Palsule <ninad@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
[ clg: - move FSICFAMState object under FSIMasterState
       - introduced fsi_master_init()
       - reworked fsi_master_realize()
       - dropped FSIBus definition ]
Signed-off-by: Cédric Le Goater <clg@kaod.org>

include/hw/fsi/fsi-master.h

@@ -0,0 +1,32 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright (C) 2024 IBM Corp.
+ *
+ * IBM Flexible Service Interface Master
+ */
+#ifndef FSI_FSI_MASTER_H
+#define FSI_FSI_MASTER_H
+
+#include "exec/memory.h"
+#include "hw/qdev-core.h"
+#include "hw/fsi/fsi.h"
+#include "hw/fsi/cfam.h"
+
+#define TYPE_FSI_MASTER "fsi.master"
+OBJECT_DECLARE_SIMPLE_TYPE(FSIMasterState, FSI_MASTER)
+
+#define FSI_MASTER_NR_REGS ((0x2e0 >> 2) + 1)
+
+typedef struct FSIMasterState {
+    DeviceState parent;
+    MemoryRegion iomem;
+    MemoryRegion opb2fsi;
+
+    FSIBus bus;
+
+    uint32_t regs[FSI_MASTER_NR_REGS];
+    FSICFAMState cfam;
+} FSIMasterState;
+
+
+#endif /* FSI_FSI_H */