From: Kane-Chen-AS <kane_c...@aspeedtech.com>
Introduce a QEMU device model for ASPEED's One-Time Programmable (OTP)
memory.
This model simulates a word-addressable OTP region used for secure
fuse storage. The OTP memory can operate with an internal memory
buffer.
The OTP model provides a memory-like interface through a dedicated
AddressSpace, allowing other device models (e.g., SBC) to issue
transactions as if accessing a memory-mapped region.
Signed-off-by: Kane-Chen-AS <kane_c...@aspeedtech.com>
---
include/hw/misc/aspeed_otpmem.h | 33 ++++++++++++
hw/misc/aspeed_otpmem.c | 91 +++++++++++++++++++++++++++++++++
hw/misc/meson.build | 1 +
3 files changed, 125 insertions(+)
create mode 100644 include/hw/misc/aspeed_otpmem.h
create mode 100644 hw/misc/aspeed_otpmem.c
diff --git a/include/hw/misc/aspeed_otpmem.h b/include/hw/misc/aspeed_otpmem.h
new file mode 100644
index 0000000000..64cd4d1a7c
--- /dev/null
+++ b/include/hw/misc/aspeed_otpmem.h
@@ -0,0 +1,33 @@
+/*
+ * ASPEED OTP (One-Time Programmable) memory
+ *
+ * Copyright (C) 2025 Aspeed
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef ASPEED_OTPMEM_H
+#define ASPEED_OTPMEM_H
+
+#include "system/memory.h"
+#include "hw/block/block.h"
+#include "system/memory.h"
+#include "system/address-spaces.h"
+
+#define OTPMEM_SIZE 0x4000
+#define TYPE_ASPEED_OTPMEM "aspeed.otpmem"
+OBJECT_DECLARE_SIMPLE_TYPE(AspeedOTPMemState, ASPEED_OTPMEM)
+
+typedef struct AspeedOTPMemState {
+ DeviceState parent_obj;
+
+ uint64_t size;
+
+ AddressSpace as;
+
+ MemoryRegion mmio;
+
+ uint8_t *storage;
+} AspeedOTPMemState;
+
+#endif /* ASPEED_OTPMEM_H */
diff --git a/hw/misc/aspeed_otpmem.c b/hw/misc/aspeed_otpmem.c
new file mode 100644
index 0000000000..a77d4186f8
--- /dev/null
+++ b/hw/misc/aspeed_otpmem.c
@@ -0,0 +1,91 @@
+/*
+ * ASPEED OTP (One-Time Programmable) memory
+ *
+ * Copyright (C) 2025 Aspeed
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "qapi/error.h"
+#include "trace.h"
+#include "system/block-backend-global-state.h"
+#include "system/block-backend-io.h"
+#include "hw/misc/aspeed_otpmem.h"
+
+static uint64_t aspeed_otpmem_read(void *opaque, hwaddr offset, unsigned size)
+{
+ AspeedOTPMemState *s = opaque;
+ uint64_t val = 0;
+
+ memcpy(&val, s->storage + offset, size);
+
+ return val;
+}
+
+static void aspeed_otpmem_write(void *opaque, hwaddr offset,
+ uint64_t val, unsigned size)
+{
+ AspeedOTPMemState *s = opaque;
+
+ memcpy(s->storage + offset, &val, size);
+}
+
+static void aspeed_otpmem_init_storage(uint8_t *storage, uint64_t size)
+{
+ uint32_t *p;
+ int i, num;
+
+ num = size / sizeof(uint32_t);
+ p = (uint32_t *)storage;
+ for (i = 0; i < num; i++) {
+ p[i] = (i % 2 == 0) ? 0x00000000 : 0xFFFFFFFF;
+ }
+}
+
+static const MemoryRegionOps aspeed_otpmem_ops = {
+ .read = aspeed_otpmem_read,
+ .write = aspeed_otpmem_write,
+ .endianness = DEVICE_LITTLE_ENDIAN,
+ .valid.min_access_size = 1,
+ .valid.max_access_size = 4,
+};
+
+static void aspeed_otpmem_realize(DeviceState *dev, Error **errp)
+{
+ AspeedOTPMemState *s = ASPEED_OTPMEM(dev);
+
+ s->storage = g_malloc(s->size);
+
+ aspeed_otpmem_init_storage(s->storage, s->size);
+
+ memory_region_init_io(&s->mmio, OBJECT(dev), &aspeed_otpmem_ops,
+ s, "aspeed.otpmem", s->size);
+ address_space_init(&s->as, &s->mmio, NULL);
+}
+
+static const Property aspeed_otpmem_properties[] = {
+ DEFINE_PROP_UINT64("size", AspeedOTPMemState, size, OTPMEM_SIZE),
+};
+
+static void aspeed_otpmem_class_init(ObjectClass *klass, const void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(klass);
+ dc->realize = aspeed_otpmem_realize;
+ device_class_set_props(dc, aspeed_otpmem_properties);
+}
+
+static const TypeInfo aspeed_otpmem_info = {
+ .name = TYPE_ASPEED_OTPMEM,
+ .parent = TYPE_DEVICE,
+ .instance_size = sizeof(AspeedOTPMemState),
+ .class_init = aspeed_otpmem_class_init,
+};
+
+static void aspeed_otpmem_register_types(void)
+{
+ type_register_static(&aspeed_otpmem_info);
+}
+
+type_init(aspeed_otpmem_register_types)
diff --git a/hw/misc/meson.build b/hw/misc/meson.build
index 6d47de482c..ed1eaaa2ad 100644
--- a/hw/misc/meson.build
+++ b/hw/misc/meson.build
@@ -136,6 +136,7 @@ system_ss.add(when: 'CONFIG_ASPEED_SOC', if_true: files(
'aspeed_sbc.c',
'aspeed_sdmc.c',
'aspeed_xdma.c',
+ 'aspeed_otpmem.c',
'aspeed_peci.c',
'aspeed_sli.c'))
--
2.43.0
