Re: [PATCH 1/2] gpu: nova-core: add initial driver stub

[John Hubbard <jhubbard@nvidia.com>]

On 2/3/25 12:24 PM, Joel Fernandes wrote:
> Hi Danilo,
> On Fri, Jan 31, 2025 at 11:04:24PM +0100, Danilo Krummrich wrote:
...
>> +const BAR0_SIZE: usize = 8;
>> +pub(crate) type Bar0 = pci::Bar<BAR0_SIZE>;
>> +
>> +kernel::pci_device_table!(
>> +    PCI_TABLE,
>> +    MODULE_PCI_TABLE,
>> +    <NovaCore as pci::Driver>::IdInfo,
>> +    [(
>> +        pci::DeviceId::from_id(bindings::PCI_VENDOR_ID_NVIDIA, bindings::PCI_ANY_ID as _),
> 
> Does this mean it will match even non-GSP Nvidia devices?
> 

Yes, it does. However, the Gpu construction a little further down
will fail on pre-GSP GPUs, thus failing the probe(), so all is well.

More below:

>> +        ()
>> +    )]
>> +);
>> +
>> +impl pci::Driver for NovaCore {
>> +    type IdInfo = ();
>> +    const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE;
>> +
>> +    fn probe(pdev: &mut pci::Device, _info: &Self::IdInfo) -> Result<Pin<KBox<Self>>> {
>> +        dev_dbg!(pdev.as_ref(), "Probe Nova Core GPU driver.\n");
>> +
>> +        pdev.enable_device_mem()?;
>> +        pdev.set_master();
>> +
>> +        let bar = pdev.iomap_region_sized::<BAR0_SIZE>(0, c_str!("nova-core"))?;
>> +
>> +        let this = KBox::pin_init(
>> +            try_pin_init!(Self {
>> +                gpu <- Gpu::new(pdev, bar)?,

Here. Try to construct a Gpu, which tries to construct a GpuSpec, which
fails out if Chipset is not listed, or if CardType (which should be
renamed to Architecture) is not listed.

And only Turing+ GPUs are listed. Turing is the first GPU that has a
GSP unit.

By the way, I have loaded this on a system with a Kepler GPU (pre-Turing),
and an Ampere GPU, and traced through actually loading NovaCore, and it
behaves as described above.

thanks,
-- 
John Hubbard