Rhys Lloyd
2025-Jul-27 09:51 UTC
[PATCH 1/2] gpu: nova-core: vbios: split out PmuLookupTableHeader from PmuLookupTable
Separating the header allows the use of
`size_of::<PmuLookupTableHeader>()`
instead of the magic number 4.
Signed-off-by: Rhys Lloyd <krakow20 at gmail.com>
---
drivers/gpu/nova-core/vbios.rs | 56 +++++++++++++++++++++-------------
1 file changed, 35 insertions(+), 21 deletions(-)
diff --git a/drivers/gpu/nova-core/vbios.rs b/drivers/gpu/nova-core/vbios.rs
index 5b5d9f38cbb3..a77d7a4c8595 100644
--- a/drivers/gpu/nova-core/vbios.rs
+++ b/drivers/gpu/nova-core/vbios.rs
@@ -889,6 +889,32 @@ fn try_from(base: BiosImageBase) -> Result<Self> {
}
}
+/// The [`PmuLookupTableHeader`] structure is header information for
[`PmuLookupTable`].
+///
+/// See the [`PmuLookupTable`] description for more information.
+#[expect(dead_code)]
+struct PmuLookupTableHeader {
+ version: u8,
+ header_len: u8,
+ entry_len: u8,
+ entry_count: u8,
+}
+
+impl PmuLookupTableHeader {
+ fn new(data: &[u8]) -> Result<Self> {
+ if data.len() < core::mem::size_of::<Self>() {
+ return Err(EINVAL);
+ }
+
+ Ok(PmuLookupTableHeader {
+ version: data[0],
+ header_len: data[1],
+ entry_len: data[2],
+ entry_count: data[3],
+ })
+ }
+}
+
/// The [`PmuLookupTableEntry`] structure is a single entry in the
[`PmuLookupTable`].
///
/// See the [`PmuLookupTable`] description for more information.
@@ -918,24 +944,18 @@ fn new(data: &[u8]) -> Result<Self> {
///
/// The table of entries is pointed to by the falcon data pointer in the BIT
table, and is used to
/// locate the Falcon Ucode.
-#[expect(dead_code)]
struct PmuLookupTable {
- version: u8,
- header_len: u8,
- entry_len: u8,
- entry_count: u8,
+ header: PmuLookupTableHeader,
table_data: KVec<u8>,
}
impl PmuLookupTable {
fn new(pdev: &pci::Device, data: &[u8]) -> Result<Self> {
- if data.len() < 4 {
- return Err(EINVAL);
- }
+ let header = PmuLookupTableHeader::new(data)?;
- let header_len = data[1] as usize;
- let entry_len = data[2] as usize;
- let entry_count = data[3] as usize;
+ let header_len = header.header_len as usize;
+ let entry_len = header.entry_len as usize;
+ let entry_count = header.entry_count as usize;
let required_bytes = header_len + (entry_count * entry_len);
@@ -963,27 +983,21 @@ fn new(pdev: &pci::Device, data: &[u8]) ->
Result<Self> {
);
}
- Ok(PmuLookupTable {
- version: data[0],
- header_len: header_len as u8,
- entry_len: entry_len as u8,
- entry_count: entry_count as u8,
- table_data,
- })
+ Ok(PmuLookupTable { header, table_data })
}
fn lookup_index(&self, idx: u8) -> Result<PmuLookupTableEntry>
{
- if idx >= self.entry_count {
+ if idx >= self.header.entry_count {
return Err(EINVAL);
}
- let index = (idx as usize) * self.entry_len as usize;
+ let index = (idx as usize) * self.header.entry_len as usize;
PmuLookupTableEntry::new(&self.table_data[index..])
}
// find entry by type value
fn find_entry_by_type(&self, entry_type: u8) ->
Result<PmuLookupTableEntry> {
- for i in 0..self.entry_count {
+ for i in 0..self.header.entry_count {
let entry = self.lookup_index(i)?;
if entry.application_id == entry_type {
return Ok(entry);
base-commit: 14ae91a81ec8fa0bc23170d4aa16dd2a20d54105
--
2.50.1
Rhys Lloyd
2025-Jul-27 09:51 UTC
[PATCH 2/2] gpu: nova-core: vbios: use offset_of in PmuLookupTableHeader::new
Use the offset_of macro for each struct field, annotate the
`PmuLookupTableHeader` struct with `#[repr(C)]` attribute,
and add a TODO message to use FromBytes when available.
Signed-off-by: Rhys Lloyd <krakow20 at gmail.com>
---
drivers/gpu/nova-core/vbios.rs | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/nova-core/vbios.rs b/drivers/gpu/nova-core/vbios.rs
index a77d7a4c8595..cedfcf3476bb 100644
--- a/drivers/gpu/nova-core/vbios.rs
+++ b/drivers/gpu/nova-core/vbios.rs
@@ -893,6 +893,7 @@ fn try_from(base: BiosImageBase) -> Result<Self> {
///
/// See the [`PmuLookupTable`] description for more information.
#[expect(dead_code)]
+#[repr(C)]
struct PmuLookupTableHeader {
version: u8,
header_len: u8,
@@ -901,16 +902,17 @@ struct PmuLookupTableHeader {
}
impl PmuLookupTableHeader {
+ // TODO[TRSM]: use FromBytes::from_bytes when it becomes available.
fn new(data: &[u8]) -> Result<Self> {
if data.len() < core::mem::size_of::<Self>() {
return Err(EINVAL);
}
Ok(PmuLookupTableHeader {
- version: data[0],
- header_len: data[1],
- entry_len: data[2],
- entry_count: data[3],
+ version: data[const { core::mem::offset_of!(PmuLookupTableHeader,
version) }],
+ header_len: data[const {
core::mem::offset_of!(PmuLookupTableHeader, header_len) }],
+ entry_len: data[const { core::mem::offset_of!(PmuLookupTableHeader,
entry_len) }],
+ entry_count: data[const {
core::mem::offset_of!(PmuLookupTableHeader, entry_count) }],
})
}
}
--
2.50.1
Alexandre Courbot
2025-Jul-29 04:34 UTC
[PATCH 1/2] gpu: nova-core: vbios: split out PmuLookupTableHeader from PmuLookupTable
On Sun Jul 27, 2025 at 6:48 PM JST, Rhys Lloyd wrote:> Separating the header allows the use of `size_of::<PmuLookupTableHeader>()` > instead of the magic number 4. > > Signed-off-by: Rhys Lloyd <krakow20 at gmail.com> > --- > drivers/gpu/nova-core/vbios.rs | 56 +++++++++++++++++++++------------- > 1 file changed, 35 insertions(+), 21 deletions(-) > > diff --git a/drivers/gpu/nova-core/vbios.rs b/drivers/gpu/nova-core/vbios.rs > index 5b5d9f38cbb3..a77d7a4c8595 100644 > --- a/drivers/gpu/nova-core/vbios.rs > +++ b/drivers/gpu/nova-core/vbios.rs > @@ -889,6 +889,32 @@ fn try_from(base: BiosImageBase) -> Result<Self> { > } > } > > +/// The [`PmuLookupTableHeader`] structure is header information for [`PmuLookupTable`]. > +/// > +/// See the [`PmuLookupTable`] description for more information. > +#[expect(dead_code)] > +struct PmuLookupTableHeader { > + version: u8, > + header_len: u8, > + entry_len: u8, > + entry_count: u8, > +} > + > +impl PmuLookupTableHeader { > + fn new(data: &[u8]) -> Result<Self> { > + if data.len() < core::mem::size_of::<Self>() {We cannot rely on `size_of::<Self>` to be 4 if `Self` is not `#[repr(C)]`. Since this is done in the second patch, I'd merge these two into a single one for simplicity.