Re: [PATCH v9 19/31] gpu: nova-core: Hopper/Blackwell: add FSP secure boot completion waiting

[Alexandre Courbot]

On Thu Mar 26, 2026 at 10:38 AM JST, John Hubbard wrote:
> Add the FSP (Firmware System Processor) module for Hopper/Blackwell GPUs.
> These architectures use a simplified firmware boot sequence:
>
>     FMC --> FSP --> GSP, with no SEC2 involvement.
>
> This commit adds the ability to wait for FSP secure boot completion by
> polling the I2CS thermal scratch register until FSP signals success.

This does more than just the boot completion waiting (which is just the
`wait_secure_boot` method) - it looks like most of the content of
`fsp.rs` should be moved to different patches.

>
> Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
> ---
>  drivers/gpu/nova-core/fsp.rs       | 148 +++++++++++++++++++++++++++++
>  drivers/gpu/nova-core/nova_core.rs |   1 +
>  drivers/gpu/nova-core/regs.rs      |  29 ++++++
>  3 files changed, 178 insertions(+)
>  create mode 100644 drivers/gpu/nova-core/fsp.rs
>
> diff --git a/drivers/gpu/nova-core/fsp.rs b/drivers/gpu/nova-core/fsp.rs
> new file mode 100644
> index 000000000000..6d32e03d89f9
> --- /dev/null
> +++ b/drivers/gpu/nova-core/fsp.rs
> @@ -0,0 +1,148 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +//! FSP (Firmware System Processor) interface for Hopper/Blackwell GPUs.
> +//!
> +//! Hopper/Blackwell use a simplified firmware boot sequence: FMC --> FSP --> GSP.
> +//! Unlike Turing/Ampere/Ada, there is NO SEC2 (Security Engine 2) usage.
> +//! FSP handles secure boot directly using FMC firmware + Chain of Trust.
> +
> +use kernel::{
> +    device,
> +    io::poll::read_poll_timeout,
> +    prelude::*,
> +    time::Delta,
> +    transmute::{
> +        AsBytes,
> +        FromBytes, //
> +    },
> +};
> +
> +use crate::regs;
> +
> +/// FSP secure boot completion timeout in milliseconds.
> +///
> +/// GB20x requires a longer timeout than Hopper/GB10x.
> +const fn fsp_secure_boot_timeout_ms(arch: crate::gpu::Architecture) -> i64 {
> +    match arch {
> +        crate::gpu::Architecture::BlackwellGB20x => 5000,
> +        _ => 4000,
> +    }
> +}

Since this is a timeout, how about harmonizing to 5000 for everyone and
turning this into a constant? Waiting 1 more second in case of a boot
failure should be acceptable. :)