Message-ID: <b5d608e6-34dd-49e8-8cdf-fabc2ab78fb0@nvidia.com>
Date: Tue, 20 May 2025 03:18:56 -0400
From: Joel Fernandes <joelagnelf@...dia.com>
To: Danilo Krummrich <dakr@...nel.org>,
 Alexandre Courbot <acourbot@...dia.com>
Cc: Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>,
 Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>,
 Björn Roy Baron <bjorn3_gh@...tonmail.com>,
 Benno Lossin <benno.lossin@...ton.me>,
 Andreas Hindborg <a.hindborg@...nel.org>, Alice Ryhl <aliceryhl@...gle.com>,
 Trevor Gross <tmgross@...ch.edu>, David Airlie <airlied@...il.com>,
 Simona Vetter <simona@...ll.ch>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 Jonathan Corbet <corbet@....net>, John Hubbard <jhubbard@...dia.com>,
 Ben Skeggs <bskeggs@...dia.com>, Timur Tabi <ttabi@...dia.com>,
 Alistair Popple <apopple@...dia.com>, linux-kernel@...r.kernel.org,
 rust-for-linux@...r.kernel.org, nouveau@...ts.freedesktop.org,
 dri-devel@...ts.freedesktop.org, Shirish Baskaran <sbaskaran@...dia.com>
Subject: Re: [PATCH v3 16/19] nova-core: Add support for VBIOS ucode
 extraction for boot

Hi Danilo,

On 5/14/2025 12:23 PM, Danilo Krummrich wrote:
>  I feel like this patch utilizes the Option type way too much and
> often without actual need. Can you please also double check?
> 

I found one other instance (vbios.fwsec_image). Other than that, all others are
required AFAICS.

>> +
>> +            if cfg!(debug_assertions) {
>> +                // Debugging (dumps the table data to dmesg):
>> +                if let Some(ref mut last_entry_bytes) = last_entry_bytes {
>> +                    last_entry_bytes.push(byte, GFP_KERNEL)?;
>> +
>> +                    let last_entry_bytes_len = last_entry_bytes.len();
>> +                    if last_entry_bytes_len == entry_len {
>> +                        pr_info!("Last entry bytes: {:02x?}\n", &last_entry_bytes[..]);
>
> Please use dev_dbg!().
>

This required passing down the pdev here, but did that, thanks.

>> +                        *last_entry_bytes = KVec::new();
>> +                    }
>> +                }
>> +            }
>> +        }
>> +
>> +        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,
>> +        })
>> +    }
>> +
>> +    fn lookup_index(&self, idx: u8) -> Result<PmuLookupTableEntry> {
>> +        if idx >= self.entry_count {
>> +            return Err(EINVAL);
>> +        }
>> +
>> +        let index = (idx as usize) * self.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 {
>> +            let entry = self.lookup_index(i)?;
>> +            if entry.application_id == entry_type {
>> +                return Ok(entry);
>> +            }
>> +        }
>> +
>> +        Err(EINVAL)
>> +    }
>> +}
>> +
>> +/// The FwSecBiosImage structure contains the PMU table and the Falcon Ucode.
>> +/// The PMU table contains voltage/frequency tables as well as a pointer to the
>> +/// Falcon Ucode.
>> +impl FwSecBiosImage {
>> +    fn setup_falcon_data(
>> +        &mut self,
>> +        pdev: &pci::Device,
>> +        pci_at_image: &PciAtBiosImage,
>> +        first_fwsec_image: &FwSecBiosImage,
>> +    ) -> Result<()> {
>
> Just Result will do.
>

Fixed.

>> +        let mut offset = pci_at_image.falcon_data_ptr(pdev)? as usize;
>> +
>> +        // The falcon data pointer assumes that the PciAt and FWSEC images
>> +        // are contiguous in memory. However, testing shows the EFI image sits in
>> +        // between them. So calculate the offset from the end of the PciAt image
>> +        // rather than the start of it. Compensate.
>> +        offset -= pci_at_image.base.data.len();
>> +
>> +        // The offset is now from the start of the first Fwsec image, however
>> +        // the offset points to a location in the second Fwsec image. Since
>> +        // the fwsec images are contiguous, subtract the length of the first Fwsec
>> +        // image from the offset to get the offset to the start of the second
>> +        // Fwsec image.
>> +        offset -= first_fwsec_image.base.data.len();
>> +
>> +        self.falcon_data_offset = Some(offset);
>> +
>> +        // The PmuLookupTable starts at the offset of the falcon data pointer
>> +        self.pmu_lookup_table = Some(PmuLookupTable::new(&self.base.data[offset..])?);
>> +
>> +        match self
>> +            .pmu_lookup_table
>> +            .as_ref()
>> +            .ok_or(EINVAL)?
>> +            .find_entry_by_type(FALCON_UCODE_ENTRY_APPID_FWSEC_PROD)
>> +        {
>> +            Ok(entry) => {
>> +                let mut ucode_offset = entry.data as usize;
>> +                ucode_offset -= pci_at_image.base.data.len();
>> +                ucode_offset -= first_fwsec_image.base.data.len();
>> +                self.falcon_ucode_offset = Some(ucode_offset);
>> +                if cfg!(debug_assertions) {
>> +                    // Print the v3_desc header for debugging
>> +                    let v3_desc = self.fwsec_header(pdev.as_ref())?;
>> +                    pr_info!("PmuLookupTableEntry v3_desc: {:#?}\n", v3_desc);
>> +                }
>> +            }
>> +            Err(e) => {
>> +                dev_err!(
>> +                    pdev.as_ref(),
>> +                    "PmuLookupTableEntry not found, error: {:?}\n",
>> +                    e
>> +                );
>> +            }
>> +        }
>> +        Ok(())
>> +    }
>> +
>> +    /// TODO: These were borrowed from the old code for integrating this module
>> +    /// with the outside world. They should be cleaned up and integrated properly.
>
> Okay, won't review for now then. 🙂

In the next revision, we are removing this TODO and can continue review. :)

thanks,

 - Joel

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