Re: [PATCH 3/8] gpu: nova-core: add TLV parser for firmware files

["Alexandre Courbot" <acourbot@nvidia.com>]

On Thu Jun 11, 2026 at 7:37 AM JST, Danilo Krummrich wrote:
<...>
>> +pub(crate) struct TlvBlock<'a> {
>> +    pub(crate) tag: &'a str,
>> +    pub(crate) value: &'a [u8],
>> +}
>> +
>> +/// On-wire TLV block header: 4-byte ASCII tag + little-endian payload length (bytes, excluding
>> +/// padding to a 4-byte boundary).
>> +struct TlvBlockHeader<'a> {
>> +    tag: &'a str,
>> +    length: usize,
>> +}
>> +
>> +impl<'a> TlvBlockHeader<'a> {
>> +    const SIZE: usize = size_of::<[u8; 4]>() + size_of::<u32>();
>> +
>> +    /// Parses the first [`Self::SIZE`] bytes of `hdr` (caller may pass a longer slice).
>> +    fn parse(hdr: &'a [u8]) -> Option<Self> {
>> +        let hdr = hdr.get(..Self::SIZE)?;
>> +        let tag_bytes = hdr.get(..4)?;
>> +        let tag = core::str::from_utf8(tag_bytes).ok()?;
>> +        if !tag.is_ascii() {
>> +            return None;
>> +        }
>> +        let len_arr = <[u8; 4]>::try_from(hdr.get(4..Self::SIZE)?).ok()?;
>> +        let length = u32::from_le_bytes(len_arr) as usize;
>
> Here and in a couple other cases, nova-core depends on !CPU_BIG_ENDIAN, so that
> shouldn't be necessary.
>
> I'm not concerned to keep it for documentation purposes, but it may be a bit
> inconsistent with the rest of the driver.

While relying in the little endianness is useful for things like using
`FromBytes` on data structures, I think it still makes sense to handle
it in cases like this one where it is easy to do so.

Code moves, and in the (remote :)) chance that TLV takes off and other
drivers want to pick it up, this is one less fix to pick.