[PATCH v2 4/7] gpu: nova-core: use `try_from` instead of `as` for u32 conversions

Alexandre Courbot
2025-10-27T12:55:05Z

There are a few situations in the driver where we convert a `usize` into
a `u32` using `as`. Even though most of these are obviously correct, use
`try_from` and let the compiler optimize wherever it is safe to do so.

Acked-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
drivers/gpu/nova-core/fb/hal/tu102.rs | 16 +++++++---------
drivers/gpu/nova-core/firmware/fwsec.rs | 8 ++++----
2 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/nova-core/fb/hal/tu102.rs b/drivers/gpu/nova-core/fb/hal/tu102.rs
index b022c781caf4..32114c3b3686 100644
--- a/drivers/gpu/nova-core/fb/hal/tu102.rs
+++ b/drivers/gpu/nova-core/fb/hal/tu102.rs
@@ -15,15 +15,13 @@ pub(super) fn read_sysmem_flush_page_gm107(bar: &Bar0) -> u64 {

pub(super) fn write_sysmem_flush_page_gm107(bar: &Bar0, addr: u64) -> Result {
// Check that the address doesn't overflow the receiving 32-bit register.
- if addr >> (u32::BITS + FLUSH_SYSMEM_ADDR_SHIFT) == 0 {
- regs::NV_PFB_NISO_FLUSH_SYSMEM_ADDR::default()
- .set_adr_39_08((addr >> FLUSH_SYSMEM_ADDR_SHIFT) as u32)
- .write(bar);
-
- Ok(())
- } else {
- Err(EINVAL)
- }
+ u32::try_from(addr >> FLUSH_SYSMEM_ADDR_SHIFT)
+ .map_err(|_| EINVAL)
+ .map(|addr| {
+ regs::NV_PFB_NISO_FLUSH_SYSMEM_ADDR::default()
+ .set_adr_39_08(addr)
+ .write(bar)
+ })
}

pub(super) fn display_enabled_gm107(bar: &Bar0) -> bool {
diff --git a/drivers/gpu/nova-core/firmware/fwsec.rs b/drivers/gpu/nova-core/firmware/fwsec.rs
index dd3420aaa2bf..ce78c1563754 100644
--- a/drivers/gpu/nova-core/firmware/fwsec.rs
+++ b/drivers/gpu/nova-core/firmware/fwsec.rs
@@ -291,7 +291,7 @@ fn new_fwsec(dev: &Device<device::Bound>, bios: &Vbios, cmd: FwsecCommand) -> Re

frts_cmd.read_vbios = ReadVbios {
ver: 1,
- hdr: size_of::<ReadVbios>() as u32,
+ hdr: u32::try_from(size_of::<ReadVbios>())?,
addr: 0,
size: 0,
flags: 2,
@@ -304,9 +304,9 @@ fn new_fwsec(dev: &Device<device::Bound>, bios: &Vbios, cmd: FwsecCommand) -> Re
} => {
frts_cmd.frts_region = FrtsRegion {
ver: 1,
- hdr: size_of::<FrtsRegion>() as u32,
- addr: (frts_addr >> 12) as u32,
- size: (frts_size >> 12) as u32,
+ hdr: u32::try_from(size_of::<FrtsRegion>())?,
+ addr: u32::try_from(frts_addr >> 12)?,
+ size: u32::try_from(frts_size >> 12)?,
ftype: NVFW_FRTS_CMD_REGION_TYPE_FB,
};

--
2.51.0