Re: [PATCH v14 2/3] rust: io: mem: add a generic iomem abstraction

[Daniel Almeida <daniel.almeida@collabora.com>]

Hi,

[…]

> +
> +/// An exclusive memory-mapped IO region.
> +///
> +/// # Invariants
> +///
> +/// - [`ExclusiveIoMem`] has exclusive access to the underlying [`IoMem`].
> +pub struct ExclusiveIoMem<const SIZE: usize> {
> +    /// The underlying `IoMem` instance.
> +    iomem: IoMem<SIZE>,
> +
> +    /// The region abstraction. This represents exclusive access to the
> +    /// range represented by the underlying `iomem`.
> +    ///
> +    /// This field is needed for ownership of the region.
> +    _region: Region,
> +}
> +
> +impl<const SIZE: usize> ExclusiveIoMem<SIZE> {
> +    /// Creates a new `ExclusiveIoMem` instance.
> +    fn ioremap(resource: &Resource) -> Result<Self> {
> +        let start = resource.start();
> +        let size = resource.size();
> +        let name = resource.name().ok_or(EINVAL)?;

Note the change above. If there’s no name, we fail.

I just noticed that this may not be the right approach, but OTOH we should note that
“not having a name” is apparently considered a bug in the C code under some
circumstances:

	struct resource *r = v, *p;

        […]

	seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
			depth * 2, "",
			width, start,
			width, end,
			r->name ? r->name : "<BAD>”); <—————


— Daniel