On Tue, Dec 23, 2025 at 5:42 PM Kane Chen <kane_chen@aspeedtech.com> wrote:
>
> From: Kane-Chen-AS <kane_chen@aspeedtech.com>
>
> Introduce a minimal QEMU device model for the ASPEED AST1700, an
> MCU-less I/O expander used in the LTPI topology defined by the
> DC-SCM 2.0 specification (see figure 2):
> https://www.opencompute.org/documents/ocp-dc-scm-2-0-ltpi-ver-1-0-pdf
>
> This initial implementation includes:
>
> * Definition of aspeed.ast1700 as a SysBusDevice
>
> * Setup of a basic memory region to reserve I/O space for future
> peripheral modeling
>
> This stub establishes the foundation for LTPI-related device emulation,
> without implementing any functional peripherals at this stage.
>
> Signed-off-by: Kane-Chen-AS <kane_chen@aspeedtech.com>
Reviewed-by: Nabih Estefan <nabihestefan@google.com>
Tested-by: Nabih Estefan <nabihestefan@google.com>
> ---
> include/hw/arm/aspeed_ast1700.h | 23 ++++++++++++++++
> hw/arm/aspeed_ast1700.c | 47 +++++++++++++++++++++++++++++++++
> hw/arm/meson.build | 1 +
> 3 files changed, 71 insertions(+)
> create mode 100644 include/hw/arm/aspeed_ast1700.h
> create mode 100644 hw/arm/aspeed_ast1700.c
>
> diff --git a/include/hw/arm/aspeed_ast1700.h b/include/hw/arm/aspeed_ast1700.h
> new file mode 100644
> index 0000000000..2a95ebfe89
> --- /dev/null
> +++ b/include/hw/arm/aspeed_ast1700.h
> @@ -0,0 +1,23 @@
> +/*
> + * ASPEED AST1700 IO Expander
> + *
> + * Copyright (C) 2025 ASPEED Technology Inc.
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +#ifndef ASPEED_AST1700_H
> +#define ASPEED_AST1700_H
> +
> +#include "hw/sysbus.h"
> +
> +#define TYPE_ASPEED_AST1700 "aspeed.ast1700"
> +
> +OBJECT_DECLARE_SIMPLE_TYPE(AspeedAST1700SoCState, ASPEED_AST1700)
> +
> +struct AspeedAST1700SoCState {
> + SysBusDevice parent_obj;
> +
> + MemoryRegion iomem;
> +};
> +
> +#endif /* ASPEED_AST1700_H */
> diff --git a/hw/arm/aspeed_ast1700.c b/hw/arm/aspeed_ast1700.c
> new file mode 100644
> index 0000000000..bb6ca2ce9e
> --- /dev/null
> +++ b/hw/arm/aspeed_ast1700.c
> @@ -0,0 +1,47 @@
> +/*
> + * ASPEED AST1700 IO Expander
> + *
> + * Copyright (C) 2025 ASPEED Technology Inc.
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#include "qemu/osdep.h"
> +#include "hw/boards.h"
> +#include "hw/qdev-core.h"
> +#include "qom/object.h"
> +#include "hw/arm/aspeed_ast1700.h"
> +
> +#define AST2700_SOC_LTPI_SIZE 0x01000000
> +
> +static void aspeed_ast1700_realize(DeviceState *dev, Error **errp)
> +{
> + AspeedAST1700SoCState *s = ASPEED_AST1700(dev);
> + SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
> +
> + /* Occupy memory space for all controllers in AST1700 */
> + memory_region_init(&s->iomem, OBJECT(s), TYPE_ASPEED_AST1700,
> + AST2700_SOC_LTPI_SIZE);
> + sysbus_init_mmio(sbd, &s->iomem);
> +}
> +
> +static void aspeed_ast1700_class_init(ObjectClass *klass, const void *data)
> +{
> + DeviceClass *dc = DEVICE_CLASS(klass);
> +
> + dc->realize = aspeed_ast1700_realize;
> +}
> +
> +static const TypeInfo aspeed_ast1700_info = {
> + .name = TYPE_ASPEED_AST1700,
> + .parent = TYPE_SYS_BUS_DEVICE,
> + .instance_size = sizeof(AspeedAST1700SoCState),
> + .class_init = aspeed_ast1700_class_init,
> +};
> +
> +static void aspeed_ast1700_register_types(void)
> +{
> + type_register_static(&aspeed_ast1700_info);
> +}
> +
> +type_init(aspeed_ast1700_register_types);
nit: missing trailing empty line.
> diff --git a/hw/arm/meson.build b/hw/arm/meson.build
> index aeaf654790..175942263d 100644
> --- a/hw/arm/meson.build
> +++ b/hw/arm/meson.build
> @@ -70,6 +70,7 @@ arm_ss.add(when: 'CONFIG_ASPEED_SOC', if_true: files(
> 'aspeed_ast10x0_evb.c',
> 'fby35.c'))
> arm_common_ss.add(when: ['CONFIG_ASPEED_SOC', 'TARGET_AARCH64'], if_true: files(
> + 'aspeed_ast1700.c',
> 'aspeed_ast27x0.c',
> 'aspeed_ast27x0_evb.c',
> 'aspeed_ast27x0-fc.c',
> --
> 2.43.0
>