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 <laur...@vivier.eu> Signed-off-by: Mark Cave-Ayland <mark.cave-ayl...@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
