Commit ade19c50 authored by Alexandre Courbot's avatar Alexandre Courbot
Browse files

gpu: nova-core: vbios: use FromBytes for NpdeStruct 



Use `from_bytes_copy_prefix` to create `NpdeStruct` instead of building
it ourselves from the bytes stream. This lets us remove a few array
accesses and results in shorter code.

Reviewed-by: default avatarJoel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Message-ID: <20251029-nova-vbios-frombytes-v1-5-ac441ebc1de3@nvidia.com>
parent 46768644

drivers/gpu/nova-core/vbios.rs

+12 −18
Original line number Diff line number Diff line
@@ -537,35 +537,29 @@ struct NpdeStruct { 
    last_image: u8,

}



// SAFETY: all bit patterns are valid for `NpdeStruct`.

unsafe impl FromBytes for NpdeStruct {}



impl NpdeStruct {

    fn new(dev: &device::Device, data: &[u8]) -> Option<Self> {

        if data.len() < core::mem::size_of::<Self>() {

            dev_dbg!(dev, "Not enough data for NpdeStruct\n");

            return None;

        }



        let mut signature = [0u8; 4];

        signature.copy_from_slice(&data[0..4]);

        let (npde, _) = NpdeStruct::from_bytes_copy_prefix(data)?;



        // Signature should be "NPDE" (0x4544504E).

        if &signature != b"NPDE" {

            dev_dbg!(dev, "Invalid signature for NpdeStruct: {:?}\n", signature);

        if &npde.signature != b"NPDE" {

            dev_dbg!(

                dev,

                "Invalid signature for NpdeStruct: {:?}\n",

                npde.signature

            );

            return None;

        }



        let subimage_len = u16::from_le_bytes([data[8], data[9]]);

        if subimage_len == 0 {

        if npde.subimage_len == 0 {

            dev_dbg!(dev, "Invalid subimage length: 0\n");

            return None;

        }



        Some(NpdeStruct {

            signature,

            npci_data_ext_rev: u16::from_le_bytes([data[4], data[5]]),

            npci_data_ext_len: u16::from_le_bytes([data[6], data[7]]),

            subimage_len,

            last_image: data[10],

        })

        Some(npde)

    }



    /// Check if this is the last image in the ROM.