[PATCH v3 09/11] gpu: nova-core: vbios: simplify setup_falcon_data

Eliot Courtney
2026-04-21T08:21:26Z

The code first computes `pmu_in_first_fwsec` or adjusts the offset and
then uses it in a branch just once to get the correct source for the PMU
table. This can be simplified to a single branch while also avoiding the
mutation of `offset`. Also, adjust the code after this to keep the
success case non-nested.

Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
---
drivers/gpu/nova-core/vbios.rs | 59 +++++++++++++++++++-----------------------
1 file changed, 26 insertions(+), 33 deletions(-)

diff --git a/drivers/gpu/nova-core/vbios.rs b/drivers/gpu/nova-core/vbios.rs
index 0c0e0402e715..d71ff5de794f 100644
--- a/drivers/gpu/nova-core/vbios.rs
+++ b/drivers/gpu/nova-core/vbios.rs
@@ -904,48 +904,41 @@ fn setup_falcon_data(
pci_at_image: &PciAtBiosImage,
first_fwsec: &FwSecBiosBuilder,
) -> Result {
- let mut offset = pci_at_image.falcon_data_offset()?;
- let mut pmu_in_first_fwsec = false;
+ let offset = pci_at_image.falcon_data_offset()?;

- // The offset is now from the start of the first Fwsec image, however
- // the offset points to a location in the second Fwsec image. Since
- // the fwsec images are contiguous, subtract the length of the first Fwsec
- // image from the offset to get the offset to the start of the second
- // Fwsec image.
- if offset < first_fwsec.base.data.len() {
- pmu_in_first_fwsec = true;
+ // 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..)
} else {
- offset -= first_fwsec.base.data.len();
- }
-
- let pmu_lookup_data = if pmu_in_first_fwsec {
- &first_fwsec.base.data[offset..]
- } else {
- self.base.data.get(offset..).ok_or(EINVAL)?
+ self.base.data.get(offset - first_fwsec.base.data.len()..)
};
- let pmu_lookup_table = PmuLookupTable::new(&self.base.dev, pmu_lookup_data)?;

- match pmu_lookup_table.find_entry_by_type(FALCON_UCODE_ENTRY_APPID_FWSEC_PROD) {
- Ok(entry) => {
- self.falcon_ucode_offset = Some(
- 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()))
- .ok_or(EINVAL)
- .inspect_err(|_| {
- dev_err!(self.base.dev, "Falcon Ucode offset not in second Fwsec.\n");
- })?,
- );
- }
- Err(e) => {
+ let pmu_lookup_table = pmu_lookup_data
+ .ok_or(EINVAL)
+ .and_then(|data| PmuLookupTable::new(&self.base.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,
"PmuLookupTableEntry not found, error: {:?}\n",
e
);
- return Err(EINVAL);
- }
- }
+ })?;
+
+ 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()))
+ .ok_or(EINVAL)
+ .inspect_err(|_| {
+ dev_err!(self.base.dev, "Falcon Ucode offset not in second Fwsec.\n");
+ })?;
+
+ self.falcon_ucode_offset = Some(falcon_ucode_offset);
Ok(())
}

--
2.53.0