MacOS reads this address to identify the hardware.
This is a basic implementation returning the ID of Quadra 800.
Details:
http://mess.redump.net/mess/driver_info/mac_technical_notes
"There are 3 ID schemes [...]
The third and most scalable is a machine ID register at 0x5ffffffc.
The top word must be 0xa55a to be valid. Then bits 15-11 are 0 for
consumer Macs, 1 for portables, 2 for high-end 68k, and 3 for high-end
PowerPC. Bit 10 is 1 if additional ID bits appear elsewhere (e.g. in VIA1).
The rest of the bits are a per-model identifier.
Model Lower 16 bits of ID
...
Quadra/Centris 610/650/800 0x2BAD"
Co-developed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
---
hw/m68k/q800.c | 29 +++++++++++++++++++++++++++++
include/hw/m68k/q800.h | 1 +
2 files changed, 30 insertions(+)
diff --git a/hw/m68k/q800.c b/hw/m68k/q800.c
index 456407898e..c1d4b98cc0 100644
--- a/hw/m68k/q800.c
+++ b/hw/m68k/q800.c
@@ -91,6 +91,9 @@
#define Q800_NUBUS_SLOTS_AVAILABLE (BIT(0x9) | BIT(0xc) | BIT(0xd) | \
BIT(0xe))
+/* Quadra 800 machine ID */
+#define Q800_MACHINE_ID 0xa55a2bad
+
/*
* The GLUE (General Logic Unit) is an Apple custom integrated circuit chip
* that performs a variety of functions (RAM management, clock generation, ...).
@@ -426,6 +429,27 @@ static const MemoryRegionOps macio_alias_ops = {
},
};
+static uint64_t machine_id_read(void *opaque, hwaddr addr, unsigned size)
+{
+ return Q800_MACHINE_ID;
+}
+
+static void machine_id_write(void *opaque, hwaddr addr, uint64_t val,
+ unsigned size)
+{
+ return;
+}
+
+static const MemoryRegionOps machine_id_ops = {
+ .read = machine_id_read,
+ .write = machine_id_write,
+ .endianness = DEVICE_BIG_ENDIAN,
+ .valid = {
+ .min_access_size = 4,
+ .max_access_size = 4,
+ },
+};
+
static void q800_machine_init(MachineState *machine)
{
Q800MachineState *m = Q800_MACHINE(machine);
@@ -488,6 +512,11 @@ static void q800_machine_init(MachineState *machine)
memory_region_add_subregion(get_system_memory(), IO_BASE + IO_SLICE,
&m->macio_alias);
+ memory_region_init_io(&m->machine_id, NULL, &machine_id_ops, NULL,
+ "Machine ID", 4);
+ memory_region_add_subregion(get_system_memory(), 0x5ffffffc,
+ &m->machine_id);
+
/* IRQ Glue */
m->glue = qdev_new(TYPE_GLUE);
object_property_set_link(OBJECT(m->glue), "cpu", OBJECT(m->cpu),
diff --git a/include/hw/m68k/q800.h b/include/hw/m68k/q800.h
index d0e37cc665..e57aec849a 100644
--- a/include/hw/m68k/q800.h
+++ b/include/hw/m68k/q800.h
@@ -37,6 +37,7 @@ struct Q800MachineState {
MemoryRegion macio;
MemoryRegion macio_alias;
+ MemoryRegion machine_id;
};
#define TYPE_Q800_MACHINE MACHINE_TYPE_NAME("q800")
--
2.30.2