Hi Cédric,
Got it, I'll rename the type to "aspeed-otp" as suggested to support the global
property syntax.
Thanks for the clarification!
Best regards,
Kane
> -----Original Message-----
> From: Cédric Le Goater <c...@kaod.org>
> Sent: Monday, June 30, 2025 2:28 PM
> To: Kane Chen <kane_c...@aspeedtech.com>; Peter Maydell
> <peter.mayd...@linaro.org>; Steven Lee <steven_...@aspeedtech.com>; Troy
> Lee <leet...@gmail.com>; Jamin Lin <jamin_...@aspeedtech.com>; Andrew
> Jeffery <and...@codeconstruct.com.au>; Joel Stanley <j...@jms.id.au>;
> open list:ASPEED BMCs <qemu-...@nongnu.org>; open list:All patches CC
> here <qemu-devel@nongnu.org>
> Cc: Troy Lee <troy_...@aspeedtech.com>
> Subject: Re: [PATCH v3 1/3] hw/misc/aspeed_otp: Add OTP device model with
> fallback RAM storage
>
> On 6/30/25 07:17, Kane Chen wrote:
> > From: Kane-Chen-AS <kane_c...@aspeedtech.com>
> >
> > This patch introduces a QEMU model of the ASPEED One-Time
> Programmable
> > (OTP) memory, used for secure fuse storage. The model simulates a
> > word-addressable OTP region with a memory-like interface via a
> > dedicated AddressSpace.
> >
> > If no external block backend is provided via the "drive" property, the
> > model automatically allocates an internal RAM-backed storage buffer to
> > hold OTP data, enabling simplified usage without CLI configuration.
> >
> > Signed-off-by: Kane-Chen-AS <kane_c...@aspeedtech.com>
> > ---
> > include/hw/nvram/aspeed_otp.h | 33 ++++++++++
> > hw/nvram/aspeed_otp.c | 113
> ++++++++++++++++++++++++++++++++++
> > hw/nvram/meson.build | 4 ++
> > 3 files changed, 150 insertions(+)
> > create mode 100644 include/hw/nvram/aspeed_otp.h
> > create mode 100644 hw/nvram/aspeed_otp.c
> >
> > diff --git a/include/hw/nvram/aspeed_otp.h
> > b/include/hw/nvram/aspeed_otp.h new file mode 100644 index
> > 0000000000..22b2195a00
> > --- /dev/null
> > +++ b/include/hw/nvram/aspeed_otp.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_OTP_H
> > +#define ASPEED_OTP_H
> > +
> > +#include "system/memory.h"
> > +#include "hw/block/block.h"
> > +#include "system/address-spaces.h"
> > +
> > +#define TYPE_ASPEED_OTP "aspeed.otp"
>
> Please change to "aspeed-otp" so that we can use :
>
> -global aspeed-otp.drive="foo"
>
> to define a backend.
>
>
> Thanks,
>
> C.
>
>
>
> > +OBJECT_DECLARE_SIMPLE_TYPE(AspeedOTPState, ASPEED_OTP)
> > +
> > +typedef struct AspeedOTPState {
> > + DeviceState parent_obj;
> > +
> > + BlockBackend *blk;
> > +
> > + uint64_t size;
> > +
> > + AddressSpace as;
> > +
> > + MemoryRegion mmio;
> > +
> > + uint8_t *storage;
> > +} AspeedOTPState;
> > +
> > +#endif /* ASPEED_OTP_H */
> > diff --git a/hw/nvram/aspeed_otp.c b/hw/nvram/aspeed_otp.c new file
> > mode 100644 index 0000000000..f018c58713
> > --- /dev/null
> > +++ b/hw/nvram/aspeed_otp.c
> > @@ -0,0 +1,113 @@
> > +/*
> > + * 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 "system/block-backend-global-state.h"
> > +#include "system/block-backend-io.h"
> > +#include "hw/qdev-properties.h"
> > +#include "hw/nvram/aspeed_otp.h"
> > +
> > +static uint64_t aspeed_otp_read(void *opaque, hwaddr offset, unsigned
> > +size) {
> > + AspeedOTPState *s = opaque;
> > + uint64_t val = 0;
> > +
> > + memcpy(&val, s->storage + offset, size);
> > +
> > + return val;
> > +}
> > +
> > +static void aspeed_otp_write(void *opaque, hwaddr offset,
> > + uint64_t val, unsigned size) {
> > + AspeedOTPState *s = opaque;
> > +
> > + memcpy(s->storage + offset, &val, size); }
> > +
> > +static bool aspeed_otp_init_storage(AspeedOTPState *s, Error **errp)
> > +{
> > + uint32_t *p;
> > + int i, num;
> > + uint64_t perm;
> > +
> > + if (s->blk) {
> > + perm = BLK_PERM_CONSISTENT_READ |
> > + (blk_supports_write_perm(s->blk) ? BLK_PERM_WRITE :
> 0);
> > + if (blk_set_perm(s->blk, perm, BLK_PERM_ALL, errp) < 0) {
> > + return false;
> > + }
> > + if (blk_pread(s->blk, 0, s->size, s->storage, 0) < 0) {
> > + error_setg(errp, "Failed to read the initial flash content");
> > + return false;
> > + }
> > + } else {
> > + num = s->size / sizeof(uint32_t);
> > + p = (uint32_t *)s->storage;
> > + for (i = 0; i < num; i++) {
> > + p[i] = (i % 2 == 0) ? 0x00000000 : 0xFFFFFFFF;
> > + }
> > + }
> > + return true;
> > +}
> > +
> > +static const MemoryRegionOps aspeed_otp_ops = {
> > + .read = aspeed_otp_read,
> > + .write = aspeed_otp_write,
> > + .endianness = DEVICE_LITTLE_ENDIAN,
> > + .valid.min_access_size = 1,
> > + .valid.max_access_size = 4,
> > +};
> > +
> > +static void aspeed_otp_realize(DeviceState *dev, Error **errp) {
> > + AspeedOTPState *s = ASPEED_OTP(dev);
> > +
> > + if (s->size == 0) {
> > + error_setg(errp, "aspeed.otp: 'size' property must be set");
> > + return;
> > + }
> > +
> > + s->storage = blk_blockalign(s->blk, s->size);
> > +
> > + if (!aspeed_otp_init_storage(s, errp)) {
> > + return;
> > + }
> > +
> > + memory_region_init_io(&s->mmio, OBJECT(dev), &aspeed_otp_ops,
> > + s, "aspeed.otp", s->size);
> > + address_space_init(&s->as, &s->mmio, NULL); }
> > +
> > +static const Property aspeed_otp_properties[] = {
> > + DEFINE_PROP_UINT64("size", AspeedOTPState, size, 0),
> > + DEFINE_PROP_DRIVE("drive", AspeedOTPState, blk), };
> > +
> > +static void aspeed_otp_class_init(ObjectClass *klass, const void
> > +*data) {
> > + DeviceClass *dc = DEVICE_CLASS(klass);
> > + dc->realize = aspeed_otp_realize;
> > + device_class_set_props(dc, aspeed_otp_properties); }
> > +
> > +static const TypeInfo aspeed_otp_info = {
> > + .name = TYPE_ASPEED_OTP,
> > + .parent = TYPE_DEVICE,
> > + .instance_size = sizeof(AspeedOTPState),
> > + .class_init = aspeed_otp_class_init,
> > +};
> > +
> > +static void aspeed_otp_register_types(void) {
> > + type_register_static(&aspeed_otp_info);
> > +}
> > +
> > +type_init(aspeed_otp_register_types)
> > diff --git a/hw/nvram/meson.build b/hw/nvram/meson.build index
> > 10f3639db6..b66f23605b 100644
> > --- a/hw/nvram/meson.build
> > +++ b/hw/nvram/meson.build
> > @@ -19,3 +19,7 @@ system_ss.add(when: 'CONFIG_XLNX_BBRAM',
> if_true:
> > files('xlnx-bbram.c'))
> >
> > specific_ss.add(when: 'CONFIG_PSERIES', if_true: files('spapr_nvram.c'))
> > specific_ss.add(when: 'CONFIG_ACPI', if_true:
> > files('fw_cfg-acpi.c'))
> > +
> > +system_ss.add(when: 'CONFIG_ASPEED_SOC', if_true: files(
> > + 'aspeed_otp.c',
> > + ))
> > \ No newline at end of file
