Commit 7f74842d authored by Alexandre Courbot's avatar Alexandre Courbot
Browse files

gpu: nova-core: vbios: use FromBytes for PmuLookupTable header 



Use `from_bytes_copy_prefix` to create the `PmuLookupTable` header
instead of building it ourselves from the bytes stream. This lets us
remove a few `as` conversions and array accesses.

Reviewed-by: default avatarJoel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Message-ID: <20251029-nova-vbios-frombytes-v1-2-ac441ebc1de3@nvidia.com>
parent e4ead68a

drivers/gpu/nova-core/vbios.rs

+21 −21
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
use kernel::error::Result;

use kernel::prelude::*;

use kernel::ptr::{Alignable, Alignment};

use kernel::transmute::FromBytes;

use kernel::types::ARef;



/// The offset of the VBIOS ROM in the BAR0 space.
@@ -865,29 +866,34 @@ fn new(data: &[u8]) -> Result<Self> { 
    }

}



#[repr(C)]

struct PmuLookupTableHeader {

    version: u8,

    header_len: u8,

    entry_len: u8,

    entry_count: u8,

}



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

unsafe impl FromBytes for PmuLookupTableHeader {}



/// The [`PmuLookupTableEntry`] structure is used to find the [`PmuLookupTableEntry`] for a given

/// application ID.

///

/// 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(dev: &device::Device, data: &[u8]) -> Result<Self> {

        if data.len() < 4 {

            return Err(EINVAL);

        }

        let (header, _) = PmuLookupTableHeader::from_bytes_copy_prefix(data).ok_or(EINVAL)?;



        let header_len = usize::from(data[1]);

        let entry_len = usize::from(data[2]);

        let entry_count = usize::from(data[3]);

        let header_len = usize::from(header.header_len);

        let entry_len = usize::from(header.entry_len);

        let entry_count = usize::from(header.entry_count);



        let required_bytes = header_len + (entry_count * entry_len);
@@ -908,27 +914,21 @@ fn new(dev: &device::Device, data: &[u8]) -> Result<Self> { 
            dev_dbg!(dev, "PMU entry: {:02x?}\n", &data[i..][..entry_len]);

        }



        Ok(PmuLookupTable {

            version: data[0],

            header_len: data[1],

            entry_len: data[2],

            entry_count: data[3],

            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 = (usize::from(idx)) * usize::from(self.entry_len);

        let index = (usize::from(idx)) * usize::from(self.header.entry_len);

        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);