The C typedef phys_addr_t is missing an analogue in Rust, meaning that
we end up using bindings::phys_addr_t or ResourceSize as a replacement
in various places throughout the kernel. Fix that by introducing a new
typedef on the Rust side. Place it next to the existing ResourceSize
typedef since they're quite related to each other.

Cc: stable@vger.kernel.org # for v6.18 [1]
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20251112-resource-phys-typedefs-v2-4-538307384f82@google.com
Link: https://lore.kernel.org/all/20251112-resource-phys-typedefs-v2-0-538307384f82@google.com/ [1]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Resource sizes are a general concept for dealing with physical
addresses, and not specific to the Resource type, which is just one way
to access physical addresses. Thus, move the typedef to the io module.

Still keep a re-export under resource. This avoids this commit from
being a flag-day, but I also think it's a useful re-export in general so
that you can import

	use kernel::io::resource::{Resource, ResourceSize};

instead of having to write

	use kernel::io::{
	    resource::Resource,
	    ResourceSize,
	};

in the specific cases where you need ResourceSize because you are using
the Resource type. Therefore I think it makes sense to keep this
re-export indefinitely and it is *not* intended as a temporary re-export
for migration purposes.

Cc: stable@vger.kernel.org # for v6.18 [1]
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20251112-resource-phys-typedefs-v2-2-538307384f82@google.com
Link: https://lore.kernel.org/all/20251112-resource-phys-typedefs-v2-0-538307384f82@google.com/ [1]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

These typedefs are always equivalent so this should not change anything,
but the code makes a lot more sense like this.

Cc: stable@vger.kernel.org
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Fixes: 493fc33ec252 ("rust: io: add resource abstraction")
Link: https://patch.msgid.link/20251112-resource-phys-typedefs-v2-1-538307384f82@google.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Commit 46f045db5a94 ("rust: Add read_poll_timeout_atomic function")
initiated the first import change in the I/O module using the agreed
"kernel vertical" import style [1].

For consistency throughout the module, adjust all other imports
accordingly.

While at it, drop unnecessary imports covered by prelude::*.

Link: https://docs.kernel.org/rust/coding-guidelines.html#imports [1]
Reviewed-by: Zhi Wang <zhiw@nvidia.com>
Link: https://patch.msgid.link/20251104133301.59402-1-dakr@kernel.org
[ Use prelude::* in io/poll.rs. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

There is no `mod flags` in this case, unlike others. Instead, they are
associated constants for the `Flags` type.

Thus reword the sentence to fix the broken intra-doc link, providing
an example of constant and linking to it to clarify which ones we are
referring to.

Fixes: 493fc33ec252 ("rust: io: add resource abstraction")
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20250722085500.1360401-1-ojeda@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

In preparation for ioremap support, add a Rust abstraction for struct
resource.

A future commit will introduce the Rust API to ioremap a resource from a
platform device. The current abstraction, therefore, adds only the
minimum API needed to get that done.

Acked-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Co-developed-by: Fiona Behrens <me@kloenk.dev>
Signed-off-by: Fiona Behrens <me@kloenk.dev>
Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com>
Link: https://lore.kernel.org/r/20250717-topics-tyr-platform_iomem-v15-1-beca780b77e3@collabora.com
[ Capitalize safety comments and end it with a period. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>