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

[Danilo Krummrich]

On Sat, Feb 01, 2025 at 09:14:48AM +0100, Karol Herbst wrote:
> On Fri, Jan 31, 2025 at 11:04 PM Danilo Krummrich <dakr@xxxxxxxxxx> wrote:
> > +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"))?;
> 
> I'm curious about the c_str! macro here. Since rust 1.78 one can do
> c"nova-core" to get a &CStr, is this not available in the r4l project
> yet or other reasons why this can't be used?

The kernel is still using kernel::str::CStr instead of core::ffi::CStr.

> Might make sense to clean
> it up kernel wide (outside this patch set) if it's guaranteed to be
> available.

Indeed, there's already an entry in the R4L issue tracker about this [1].
There's also a patch series [2] addressing it, but it seems that the series
didn't get an update for quite a while.

[1] https://github.com/Rust-for-Linux/linux/issues/1075
[2] https://lore.kernel.org/rust-for-linux/20240819153656.28807-2-vadorovsky@xxxxxxxxxxxxxx/