Re: [PATCH v8 06/31] gpu: nova-core: Hopper/Blackwell: skip GFW boot waiting

[Gary Guo]

On Wed Mar 25, 2026 at 3:52 AM GMT, John Hubbard wrote:
> Hopper and Blackwell GPUs use FSP-based secure boot and do not
> require waiting for GFW_BOOT completion. Move the GFW_BOOT wait
> into a GPU HAL so the decision and the wait both live in the HAL.
>
> Pre-Hopper families (Tu102 HAL) wait for GFW_BOOT completion.
> Hopper and later (Gh100 HAL) skip it and boot via FSP instead.
>
> Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
> ---
>  drivers/gpu/nova-core/gpu.rs     |  6 +++--
>  drivers/gpu/nova-core/gpu/hal.rs | 42 ++++++++++++++++++++++++++++++++
>  2 files changed, 46 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/gpu/nova-core/gpu/hal.rs
>
> diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
> index e7c3860cfb28..5cef5b29cd3f 100644
> --- a/drivers/gpu/nova-core/gpu.rs
> +++ b/drivers/gpu/nova-core/gpu.rs
> @@ -18,11 +18,12 @@
>          Falcon, //
>      },
>      fb::SysmemFlush,
> -    gfw,
>      gsp::Gsp,
>      regs,
>  };
>  
> +mod hal;
> +
>  macro_rules! define_chipset {
>      ({ $($variant:ident = $value:expr),* $(,)* }) =>
>      {
> @@ -309,10 +310,11 @@ pub(crate) fn new<'a>(
>          spec: Spec,
>      ) -> impl PinInit<Self, Error> + 'a {
>          let chipset = spec.chipset();
> +        let hal = hal::gpu_hal(chipset);
>  
>          try_pin_init!(Self {
>              _: {
> -                gfw::wait_gfw_boot_completion(bar)
> +                hal.wait_gfw_boot_completion(bar)
>                      .inspect_err(|_| dev_err!(pdev, "GFW boot did not complete\n"))?;
>              },
>  
> diff --git a/drivers/gpu/nova-core/gpu/hal.rs b/drivers/gpu/nova-core/gpu/hal.rs
> new file mode 100644
> index 000000000000..2f9e18e67a35
> --- /dev/null
> +++ b/drivers/gpu/nova-core/gpu/hal.rs
> @@ -0,0 +1,42 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +use kernel::prelude::*;
> +
> +use crate::{
> +    driver::Bar0,
> +    gfw,
> +    gpu::{
> +        Architecture,
> +        Chipset, //
> +    },
> +};
> +
> +pub(crate) trait GpuHal {
> +    /// Waits for GFW_BOOT completion if required by this hardware family.
> +    fn wait_gfw_boot_completion(&self, bar: &Bar0) -> Result;
> +}
> +
> +struct Tu102;
> +struct Gh100;
> +
> +impl GpuHal for Tu102 {
> +    fn wait_gfw_boot_completion(&self, bar: &Bar0) -> Result {
> +        gfw::wait_gfw_boot_completion(bar)
> +    }
> +}
> +
> +impl GpuHal for Gh100 {
> +    fn wait_gfw_boot_completion(&self, _bar: &Bar0) -> Result {
> +        Ok(())
> +    }
> +}
> +
> +const TU102: Tu102 = Tu102;
> +const GH100: Gh100 = Gh100;
> +

Why this instead of using `Tu102` and `Gh100` directly? They already exist in
value namespace due to the type being unit struct.

Best,
Gary

> +pub(super) fn gpu_hal(chipset: Chipset) -> &'static dyn GpuHal {
> +    match chipset.arch() {
> +        Architecture::Turing | Architecture::Ampere | Architecture::Ada => &TU102,
> +        Architecture::Hopper | Architecture::Blackwell => &GH100,
> +    }
> +}