hw/m68k: add Nubus support

This patch adds basic support for the NuBus bus. This is used by 680x0
Macintosh.

Co-developed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Thomas Huth <huth@tuxfamily.org>
Message-Id: <20191026164546.30020-8-laurent@vivier.eu>

1 files changed, 111 insertions, 0 deletions

diff --git a/hw/nubus/nubus-bus.c b/hw/nubus/nubus-bus.c
new file mode 100644
index 0000000..942a6d5
--- /dev/null
+++ b/hw/nubus/nubus-bus.c
@@ -0,0 +1,111 @@
+/*
+ * QEMU Macintosh Nubus
+ *
+ * Copyright (c) 2013-2018 Laurent Vivier <laurent@vivier.eu>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "hw/nubus/nubus.h"
+#include "hw/sysbus.h"
+#include "qapi/error.h"
+
+
+static NubusBus *nubus_find(void)
+{
+    /* Returns NULL unless there is exactly one nubus device */
+    return NUBUS_BUS(object_resolve_path_type("", TYPE_NUBUS_BUS, NULL));
+}
+
+static void nubus_slot_write(void *opaque, hwaddr addr, uint64_t val,
+                             unsigned int size)
+{
+    /* read only */
+}
+
+
+static uint64_t nubus_slot_read(void *opaque, hwaddr addr,
+                                unsigned int size)
+{
+    return 0;
+}
+
+static const MemoryRegionOps nubus_slot_ops = {
+    .read  = nubus_slot_read,
+    .write = nubus_slot_write,
+    .endianness = DEVICE_BIG_ENDIAN,
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+};
+
+static void nubus_super_slot_write(void *opaque, hwaddr addr, uint64_t val,
+                                   unsigned int size)
+{
+    /* read only */
+}
+
+static uint64_t nubus_super_slot_read(void *opaque, hwaddr addr,
+                                      unsigned int size)
+{
+    return 0;
+}
+
+static const MemoryRegionOps nubus_super_slot_ops = {
+    .read  = nubus_super_slot_read,
+    .write = nubus_super_slot_write,
+    .endianness = DEVICE_BIG_ENDIAN,
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+};
+
+static void nubus_realize(BusState *bus, Error **errp)
+{
+    if (!nubus_find()) {
+        error_setg(errp, "at most one %s device is permitted", TYPE_NUBUS_BUS);
+        return;
+    }
+}
+
+static void nubus_init(Object *obj)
+{
+    NubusBus *nubus = NUBUS_BUS(obj);
+
+    memory_region_init_io(&nubus->super_slot_io, obj, &nubus_super_slot_ops,
+                          nubus, "nubus-super-slots",
+                          NUBUS_SUPER_SLOT_NB * NUBUS_SUPER_SLOT_SIZE);
+
+    memory_region_init_io(&nubus->slot_io, obj, &nubus_slot_ops,
+                          nubus, "nubus-slots",
+                          NUBUS_SLOT_NB * NUBUS_SLOT_SIZE);
+
+    nubus->current_slot = NUBUS_FIRST_SLOT;
+}
+
+static void nubus_class_init(ObjectClass *oc, void *data)
+{
+    BusClass *bc = BUS_CLASS(oc);
+
+    bc->realize = nubus_realize;
+}
+
+static const TypeInfo nubus_bus_info = {
+    .name = TYPE_NUBUS_BUS,
+    .parent = TYPE_BUS,
+    .instance_size = sizeof(NubusBus),
+    .instance_init = nubus_init,
+    .class_init = nubus_class_init,
+};
+
+static void nubus_register_types(void)
+{
+    type_register_static(&nubus_bus_info);
+}
+
+type_init(nubus_register_types)