[PATCH v8 04/10] hw/fsi: IBM's On-chip Peripheral Bus

[Ninad Palsule <ninad@linux.ibm.com>]

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

The On-Chip Peripheral Bus (OPB): A low-speed bus typically found in
POWER processors. This now makes an appearance in the ASPEED SoC due
to tight integration of the FSI master IP with the OPB, mainly the
existence of an MMIO-mapping of the CFAM address straight onto a
sub-region of the OPB address space.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Ninad Palsule <ninad@linux.ibm.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
[ clg: - removed FSIMasterState object and fsi_opb_realize()
       - simplified OPBus ]
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 include/hw/fsi/opb.h | 25 +++++++++++++++++++++++++
 hw/fsi/opb.c         | 36 ++++++++++++++++++++++++++++++++++++
 hw/fsi/Kconfig       |  4 ++++
 hw/fsi/meson.build   |  1 +
 4 files changed, 66 insertions(+)
 create mode 100644 include/hw/fsi/opb.h
 create mode 100644 hw/fsi/opb.c

diff --git a/include/hw/fsi/opb.h b/include/hw/fsi/opb.h
new file mode 100644
index 0000000000..c112206f9e
--- /dev/null
+++ b/include/hw/fsi/opb.h
@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright (C) 2023 IBM Corp.
+ *
+ * IBM On-Chip Peripheral Bus
+ */
+#ifndef FSI_OPB_H
+#define FSI_OPB_H
+
+#include "exec/memory.h"
+#include "hw/fsi/fsi-master.h"
+
+#define TYPE_OP_BUS "opb"
+OBJECT_DECLARE_SIMPLE_TYPE(OPBus, OP_BUS)
+
+typedef struct OPBus {
+        /*< private >*/
+        BusState bus;
+
+        /*< public >*/
+        MemoryRegion mr;
+        AddressSpace as;
+} OPBus;
+
+#endif /* FSI_OPB_H */
diff --git a/hw/fsi/opb.c b/hw/fsi/opb.c
new file mode 100644
index 0000000000..6474754890
--- /dev/null
+++ b/hw/fsi/opb.c
@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright (C) 2023 IBM Corp.
+ *
+ * IBM On-chip Peripheral Bus
+ */
+
+#include "qemu/osdep.h"
+
+#include "qapi/error.h"
+#include "qemu/log.h"
+
+#include "hw/fsi/opb.h"
+
+static void fsi_opb_init(Object *o)
+{
+    OPBus *opb = OP_BUS(o);
+
+    memory_region_init_io(&opb->mr, OBJECT(opb), NULL, opb,
+                          NULL, UINT32_MAX);
+    address_space_init(&opb->as, &opb->mr, "opb");
+}
+
+static const TypeInfo opb_info = {
+    .name = TYPE_OP_BUS,
+    .parent = TYPE_BUS,
+    .instance_init = fsi_opb_init,
+    .instance_size = sizeof(OPBus),
+};
+
+static void fsi_opb_register_types(void)
+{
+    type_register_static(&opb_info);
+}
+
+type_init(fsi_opb_register_types);
diff --git a/hw/fsi/Kconfig b/hw/fsi/Kconfig
index de1594a335..9755baa8cc 100644
--- a/hw/fsi/Kconfig
+++ b/hw/fsi/Kconfig
@@ -1,3 +1,7 @@
+config FSI_OPB
+    bool
+    select FSI_CFAM
+
 config FSI_CFAM
     bool
     select FSI
diff --git a/hw/fsi/meson.build b/hw/fsi/meson.build
index cafd009c6d..ba92881370 100644
--- a/hw/fsi/meson.build
+++ b/hw/fsi/meson.build
@@ -1,3 +1,4 @@
 system_ss.add(when: 'CONFIG_FSI_LBUS', if_true: files('lbus.c'))
 system_ss.add(when: 'CONFIG_FSI_CFAM', if_true: files('cfam.c'))
 system_ss.add(when: 'CONFIG_FSI', if_true: files('fsi.c','fsi-slave.c'))
+system_ss.add(when: 'CONFIG_FSI_OPB', if_true: files('opb.c'))
-- 
2.39.2