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

[John Hubbard]

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