[PATCH v3 2/2] lib: utils/reset: Add Metanoia MT2824 system reset driver

[Anup Patel]

On Fri, Jul 24, 2026 at 9:05 PM Benoît Monin <benoit.monin at bootlin.com> wrote:
>
> Add a driver for the system reset function found in Metanoia MT2824 SoC
> and enable it in the generic platform configuration.
>
> Originally-by: Jun Chang <jun.chang at metanoia-comm.com>
> Signed-off-by: Benoît Monin <benoit.monin at bootlin.com>
> ---
>  lib/utils/reset/Kconfig              |  4 ++
>  lib/utils/reset/fdt_reset_metanoia.c | 72 ++++++++++++++++++++++++++++++++++++
>  lib/utils/reset/objects.mk           |  3 ++
>  platform/generic/configs/defconfig   |  1 +
>  4 files changed, 80 insertions(+)
>
> diff --git a/lib/utils/reset/Kconfig b/lib/utils/reset/Kconfig
> index b2ac120e..8988548c 100644
> --- a/lib/utils/reset/Kconfig
> +++ b/lib/utils/reset/Kconfig
> @@ -29,6 +29,10 @@ config FDT_RESET_LITEX
>         depends on FDT_GPIO
>         default n
>
> +config FDT_RESET_METANOIA
> +       bool "Metanoia FDT reset driver"
> +       default n
> +
>  config FDT_RESET_RPMI
>         bool "RPMI FDT reset driver"
>         depends on FDT_MAILBOX && RPMI_MAILBOX
> diff --git a/lib/utils/reset/fdt_reset_metanoia.c b/lib/utils/reset/fdt_reset_metanoia.c
> new file mode 100644
> index 00000000..628cd8b6
> --- /dev/null
> +++ b/lib/utils/reset/fdt_reset_metanoia.c
> @@ -0,0 +1,72 @@
> +/*
> + * SPDX-License-Identifier: BSD-2-Clause
> + *
> + * Copyright (c) 2026 Metanoia Communications Inc.
> + *
> + */
> +
> +#include <sbi/riscv_io.h>
> +#include <sbi/sbi_platform.h>
> +#include <sbi/sbi_system.h>
> +#include <sbi_utils/fdt/fdt_helper.h>
> +#include <sbi_utils/fdt/fdt_driver.h>
> +
> +#define SWRSTREQ_CTRL_REG_OFFSET 0x00
> +#define SWRSTREQ_REG_OFFSET 0x04
> +
> +struct reset_metanoia_data {
> +       u8 *reg_base;
> +};
> +
> +static struct reset_metanoia_data reset_data;
> +
> +static int metanoia_system_reset_check(u32 type, u32 reason)
> +{
> +       switch (type) {
> +       case SBI_SRST_RESET_TYPE_WARM_REBOOT:
> +       case SBI_SRST_RESET_TYPE_COLD_REBOOT:
> +               return 1;
> +       case SBI_SRST_RESET_TYPE_SHUTDOWN:
> +       default:
> +               return 0;
> +       }
> +}
> +
> +static void metanoia_system_reset(u32 type, u32 reason)
> +{
> +       writew(0x1, reset_data.reg_base + SWRSTREQ_CTRL_REG_OFFSET);
> +       writew(0x1, reset_data.reg_base + SWRSTREQ_REG_OFFSET);
> +}
> +
> +static struct sbi_system_reset_device metanoia_reset = {
> +       .name               = "metanoia-mt2824-reboot",
> +       .system_reset_check = metanoia_system_reset_check,
> +       .system_reset       = metanoia_system_reset,
> +};
> +
> +static int metanoia_reset_init(const void *fdt, int nodeoff,
> +                              const struct fdt_match *match)
> +{
> +       u64 reg_addr;
> +       int rc;
> +
> +       rc = fdt_get_node_addr_size(fdt, nodeoff, 0, &reg_addr, NULL);
> +       if (rc < 0 || !reg_addr)
> +               return SBI_ENODEV;
> +
> +       reset_data.reg_base = (u8 *)reg_addr;

This needs to be "(u8 *)(ulong)" typecast to avoid compile errors for RV32.
I will update at the time of merging this patch.

> +
> +       sbi_system_reset_add_device(&metanoia_reset);
> +
> +       return 0;
> +}
> +
> +static const struct fdt_match metanoia_reset_match[] = {
> +       { .compatible = "metanoia,mt2824-reboot" },
> +       { /* sentinel */ }
> +};
> +
> +const struct fdt_driver fdt_reset_metanoia = {
> +       .match_table = metanoia_reset_match,
> +       .init        = metanoia_reset_init,
> +};
> diff --git a/lib/utils/reset/objects.mk b/lib/utils/reset/objects.mk
> index 38b4e306..a9b6edad 100644
> --- a/lib/utils/reset/objects.mk
> +++ b/lib/utils/reset/objects.mk
> @@ -20,6 +20,9 @@ libsbiutils-objs-$(CONFIG_FDT_RESET_HTIF) += reset/fdt_reset_htif.o
>  carray-fdt_early_drivers-$(CONFIG_FDT_RESET_LITEX) += fdt_reset_litex
>  libsbiutils-objs-$(CONFIG_FDT_RESET_LITEX) += reset/fdt_reset_litex.o
>
> +carray-fdt_early_drivers-$(CONFIG_FDT_RESET_METANOIA) += fdt_reset_metanoia
> +libsbiutils-objs-$(CONFIG_FDT_RESET_METANOIA) += reset/fdt_reset_metanoia.o
> +
>  carray-fdt_early_drivers-$(CONFIG_FDT_RESET_SG2042_HWMON_MCU) += fdt_reset_sg2042_mcu
>  libsbiutils-objs-$(CONFIG_FDT_RESET_SG2042_HWMON_MCU) += reset/fdt_reset_sg2042_hwmon_mcu.o
>
> diff --git a/platform/generic/configs/defconfig b/platform/generic/configs/defconfig
> index 820c98b6..ac76eb27 100644
> --- a/platform/generic/configs/defconfig
> +++ b/platform/generic/configs/defconfig
> @@ -52,6 +52,7 @@ CONFIG_FDT_RESET_ATCWDT200=y
>  CONFIG_FDT_RESET_GPIO=y
>  CONFIG_FDT_RESET_LITEX=y
>  CONFIG_FDT_RESET_HTIF=y
> +CONFIG_FDT_RESET_METANOIA=y
>  CONFIG_FDT_RESET_RPMI=y
>  CONFIG_FDT_RESET_SG2042_HWMON_MCU=y
>  CONFIG_FDT_RESET_SPACEMIT_P1=y
>
> --
> 2.55.0
>
>
> --
> opensbi mailing list
> opensbi at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/opensbi

Otherwise LGTM.

Reviewed-by: Anup Patel <anup at brainfault.org>

Applied this patch to the riscv/opensbi repo.

Thanks,
Anup