Re: [PATCH v2 10/11] gpu: nova-core: vbios: construct `FwSecBiosImage` directly from BIOS images

[Joel Fernandes <joelagnelf@nvidia.com>]

On 4/14/2026 7:54 AM, Eliot Courtney wrote:
> `FwSecBiosBuilder` now only contains `falcon_ucode_offset` which just
> gets passed directly into `FwSecBiosImage`. Remove `FwSecBiosBuilder`
> and construct `FwSecBiosImage` directly, as a simplification.
> 

nice :) The reason for the builder object was, we wanted to have a
'calculate' phase and a 'build object now' phase to avoid the problem of
partially constructed objects. However, as you showed we can accomplish
that without an intermediary objects.

Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>

Thanks.


> Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
> ---
>  drivers/gpu/nova-core/vbios.rs | 98 +++++++++++++++++-------------------------
>  1 file changed, 39 insertions(+), 59 deletions(-)
> 
> diff --git a/drivers/gpu/nova-core/vbios.rs b/drivers/gpu/nova-core/vbios.rs
> index d71ff5de794f..5cc251c73800 100644
> --- a/drivers/gpu/nova-core/vbios.rs
> +++ b/drivers/gpu/nova-core/vbios.rs
> @@ -233,8 +233,8 @@ impl Vbios {
>      pub(crate) fn new(dev: &device::Device, bar0: &Bar0) -> Result<Vbios> {
>          // Images to extract from iteration
>          let mut pci_at_image: Option<PciAtBiosImage> = None;
> -        let mut first_fwsec_image: Option<FwSecBiosBuilder> = None;
> -        let mut second_fwsec_image: Option<FwSecBiosBuilder> = None;
> +        let mut first_fwsec_image: Option<BiosImage> = None;
> +        let mut second_fwsec_image: Option<BiosImage> = None;
>  
>          // Parse all VBIOS images in the ROM
>          for image_result in VbiosIterator::new(dev, bar0)? {
> @@ -254,14 +254,10 @@ pub(crate) fn new(dev: &device::Device, bar0: &Bar0) -> Result<Vbios> {
>                      pci_at_image = Some(PciAtBiosImage::try_from(image)?);
>                  }
>                  Ok(BiosImageType::FwSec) => {
> -                    let fwsec = FwSecBiosBuilder {
> -                        base: image,
> -                        falcon_ucode_offset: None,
> -                    };
>                      if first_fwsec_image.is_none() {
> -                        first_fwsec_image = Some(fwsec);
> +                        first_fwsec_image = Some(image);
>                      } else {
> -                        second_fwsec_image = Some(fwsec);
> +                        second_fwsec_image = Some(image);
>                      }
>                  }
>                  _ => {
> @@ -271,15 +267,23 @@ pub(crate) fn new(dev: &device::Device, bar0: &Bar0) -> Result<Vbios> {
>          }
>  
>          // Using all the images, setup the falcon data pointer in Fwsec.
> -        if let (Some(mut second), Some(first), Some(pci_at)) =
> +        if let (Some(second), Some(first), Some(pci_at)) =
>              (second_fwsec_image, first_fwsec_image, pci_at_image)
>          {
> -            second
> -                .setup_falcon_data(&pci_at, &first)
> +            let fwsec_image = FwSecBiosImage::new(pci_at, first, second)
>                  .inspect_err(|e| dev_err!(dev, "Falcon data setup failed: {:?}\n", e))?;
> -            Ok(Vbios {
> -                fwsec_image: second.build()?,
> -            })
> +
> +            if cfg!(debug_assertions) {
> +                // Print the desc header for debugging
> +                let desc = fwsec_image.header()?;
> +                dev_dbg!(
> +                    fwsec_image.base.dev,
> +                    "PmuLookupTableEntry desc: {:#?}\n",
> +                    desc
> +                );
> +            }
> +
> +            Ok(Vbios { fwsec_image })
>          } else {
>              dev_err!(
>                  dev,
> @@ -621,18 +625,6 @@ struct NbsiBiosImage {
>      // NBSI-specific fields can be added here in the future.
>  }
>  
> -struct FwSecBiosBuilder {
> -    base: BiosImage,
> -    /// These are temporary fields that are used during the construction of the
> -    /// [`FwSecBiosBuilder`].
> -    ///
> -    /// Once FwSecBiosBuilder is constructed, the `falcon_ucode_offset` will be copied into a new
> -    /// [`FwSecBiosImage`].
> -    ///
> -    /// The offset of the Falcon ucode.
> -    falcon_ucode_offset: Option<usize>,
> -}
> -
>  /// The [`FwSecBiosImage`] structure contains the PMU table and the Falcon Ucode.
>  ///
>  /// The PMU table contains voltage/frequency tables as well as a pointer to the Falcon Ucode.
> @@ -898,33 +890,34 @@ fn find_entry_by_type(&self, entry_type: u8) -> Result<PmuLookupTableEntry> {
>      }
>  }
>  
> -impl FwSecBiosBuilder {
> -    fn setup_falcon_data(
> -        &mut self,
> -        pci_at_image: &PciAtBiosImage,
> -        first_fwsec: &FwSecBiosBuilder,
> -    ) -> Result {
> +impl FwSecBiosImage {
> +    /// Build the final `FwSecBiosImage` from the PCI-AT and FWSEC BIOS images
> +    fn new(
> +        pci_at_image: PciAtBiosImage,
> +        first_fwsec: BiosImage,
> +        second_fwsec: BiosImage,
> +    ) -> Result<FwSecBiosImage> {
>          let offset = pci_at_image.falcon_data_offset()?;
>  
>          // The offset is from the start of the first FwSec image, but it
>          // may point into the second FwSec image. Treat the two FwSec images
>          // as contiguous here and subtract the first image length when the
>          // target lies in the second one.
> -        let pmu_lookup_data = if offset < first_fwsec.base.data.len() {
> -            first_fwsec.base.data.get(offset..)
> +        let pmu_lookup_data = if offset < first_fwsec.data.len() {
> +            first_fwsec.data.get(offset..)
>          } else {
> -            self.base.data.get(offset - first_fwsec.base.data.len()..)
> +            second_fwsec.data.get(offset - first_fwsec.data.len()..)
>          };
>  
>          let pmu_lookup_table = pmu_lookup_data
>              .ok_or(EINVAL)
> -            .and_then(|data| PmuLookupTable::new(&self.base.dev, data))?;
> +            .and_then(|data| PmuLookupTable::new(&second_fwsec.dev, data))?;
>  
>          let entry = pmu_lookup_table
>              .find_entry_by_type(FALCON_UCODE_ENTRY_APPID_FWSEC_PROD)
>              .inspect_err(|e| {
>                  dev_err!(
> -                    self.base.dev,
> +                    second_fwsec.dev,
>                      "PmuLookupTableEntry not found, error: {:?}\n",
>                      e
>                  );
> @@ -932,34 +925,21 @@ fn setup_falcon_data(
>  
>          let falcon_ucode_offset = usize::from_safe_cast(entry.data)
>              .checked_sub(pci_at_image.base.data.len())
> -            .and_then(|o| o.checked_sub(first_fwsec.base.data.len()))
> +            .and_then(|o| o.checked_sub(first_fwsec.data.len()))
>              .ok_or(EINVAL)
>              .inspect_err(|_| {
> -                dev_err!(self.base.dev, "Falcon Ucode offset not in second Fwsec.\n");
> +                dev_err!(
> +                    second_fwsec.dev,
> +                    "Falcon Ucode offset not in second Fwsec.\n"
> +                );
>              })?;
>  
> -        self.falcon_ucode_offset = Some(falcon_ucode_offset);
> -        Ok(())
> +        Ok(FwSecBiosImage {
> +            base: second_fwsec,
> +            falcon_ucode_offset,
> +        })
>      }
>  
> -    /// Build the final FwSecBiosImage from this builder
> -    fn build(self) -> Result<FwSecBiosImage> {
> -        let ret = FwSecBiosImage {
> -            base: self.base,
> -            falcon_ucode_offset: self.falcon_ucode_offset.ok_or(EINVAL)?,
> -        };
> -
> -        if cfg!(debug_assertions) {
> -            // Print the desc header for debugging
> -            let desc = ret.header()?;
> -            dev_dbg!(ret.base.dev, "PmuLookupTableEntry desc: {:#?}\n", desc);
> -        }
> -
> -        Ok(ret)
> -    }
> -}
> -
> -impl FwSecBiosImage {
>      /// Get the FwSec header ([`FalconUCodeDesc`]).
>      pub(crate) fn header(&self) -> Result<FalconUCodeDesc> {
>          let data = self
>