linux-toradex.git/rust/kernel/io.rs, branch v7.0-rc7

rust: io: macro_export io_define_read!() and io_define_write!()

2026-02-22T23:54:02+00:00

Currently, the define_read!() and define_write!() I/O macros are crate
public. The only user outside of the I/O module is PCI (for the
configurations space I/O backend). Consequently, when CONFIG_PCI=n this
causes a compile time warning [1].

In order to fix this, rename the macros to io_define_read!() and
io_define_write!() and use #[macro_export] to export them.

This is better than making the crate public visibility conditional, as
eventually subsystems will have their own crate.

Also, I/O backends are valid to be implemented by drivers as well. For
instance, there are devices (such as GPUs) that run firmware which
allows to program other devices only accessible through the primary
device through indirect I/O.

Since the macros are now public, also add the corresponding
documentation.

Fixes: 121d87b28e1d ("rust: io: separate generic I/O helpers from MMIO implementation")
Reported-by: Miguel Ojeda 
Closes: https://lore.kernel.org/driver-core/CANiq72khOYkt6t5zwMvSiyZvWWHMZuNCMERXu=7K=_5tT-8Pgg@mail.gmail.com/ [1]
Reviewed-by: Alice Ryhl 
Reviewed-by: Daniel Almeida 
Link: https://patch.msgid.link/20260216131534.65008-1-dakr@kernel.org
Signed-off-by: Danilo Krummrich

rust: io: move MIN_SIZE and io_addr_assert to IoKnownSize

2026-02-01T21:23:59+00:00

`MIN_SIZE` and `io_addr_assert` are only ever used for IO types which
implement `IoKnownSize` and do not make sense for types that don't.

It looks like they should have been there since the beginning, so move
them while the code is still fresh.

Also update `IoKnownSize`'s documentation since it is not just a marker
trait anymore.

Fixes: 121d87b28e1d ("rust: io: separate generic I/O helpers from MMIO implementation")
Signed-off-by: Alexandre Courbot 
Link: https://patch.msgid.link/20260130-io-min-size-v1-1-65a546e3104d@nvidia.com
[ Fix typo in commit message. - Danilo ]
Signed-off-by: Danilo Krummrich

Merge tag 'v6.19-rc7' into driver-core-next

2026-01-26T12:23:52+00:00

We need the driver-core fixes in here as well to build on top of.

Signed-off-by: Danilo Krummrich

rust: pci: add config space read/write support

2026-01-23T20:23:16+00:00

Drivers might need to access PCI config space for querying capability
structures and access the registers inside the structures.

For Rust drivers need to access PCI config space, the Rust PCI abstraction
needs to support it in a way that upholds Rust's safety principles.

Introduce a `ConfigSpace` wrapper in Rust PCI abstraction to provide safe
accessors for PCI config space. The new type implements the `Io` trait and
`IoCapable` for u8, u16, and u32 to share offset validation and
bound-checking logic with other I/O backends.

The `ConfigSpace` type uses marker types (`Normal` and `Extended`) to
represent configuration space sizes at the type level.

Cc: Alexandre Courbot 
Cc: Danilo Krummrich 
Cc: Gary Guo 
Cc: Joel Fernandes 
Signed-off-by: Zhi Wang 
Reviewed-by: Gary Guo 
Link: https://lore.kernel.org/all/DFV4IJDQC2J6.1Q91JOAL6CJSG@kernel.org/ [1]
Link: https://patch.msgid.link/20260121202212.4438-5-zhiw@nvidia.com
[ Applied the diff from [1], considering subsequent comment; remove
  #[expect(unused)] from define_{read,write}!(). - Danilo ]
Signed-off-by: Danilo Krummrich

rust: io: factor out MMIO read/write macros

2026-01-23T20:21:39+00:00

Refactor the existing MMIO accessors to use common call macros
instead of inlining the bindings calls in each `define_{read,write}!`
expansion.

This factoring separates the common offset/bounds checks from the
low-level call pattern, making it easier to add additional I/O accessor
families.

No functional change intended.

Cc: Alexandre Courbot 
Signed-off-by: Zhi Wang 
Reviewed-by: Alexandre Courbot 
Link: https://patch.msgid.link/20260121202212.4438-4-zhiw@nvidia.com
Signed-off-by: Danilo Krummrich

rust: io: separate generic I/O helpers from MMIO implementation

2026-01-23T20:20:11+00:00

The previous Io type combined both the generic I/O access helpers
and MMIO implementation details in a single struct. This coupling prevented
reusing the I/O helpers for other backends, such as PCI configuration
space.

Establish a clean separation between the I/O interface and concrete
backends by separating generic I/O helpers from MMIO implementation.

Introduce a new trait hierarchy to handle different access capabilities:

- IoCapable: A marker trait indicating that a backend supports I/O
  operations of a certain type (u8, u16, u32, or u64).

- Io trait: Defines fallible (try_read8, try_write8, etc.) and infallibile
  (read8, write8, etc.) I/O methods with runtime bounds checking and
  compile-time bounds checking.

- IoKnownSize trait: The marker trait for types support infallible I/O
  methods.

Move the MMIO-specific logic into a dedicated Mmio type that
implements the Io traits. Rename IoRaw to MmioRaw and update consumers to
use the new types.

Cc: Alexandre Courbot 
Cc: Alice Ryhl 
Cc: Bjorn Helgaas 
Cc: Gary Guo 
Cc: Danilo Krummrich 
Cc: John Hubbard 
Signed-off-by: Zhi Wang 
Reviewed-by: Alice Ryhl 
Reviewed-by: Alexandre Courbot 
Reviewed-by: Gary Guo 
Link: https://patch.msgid.link/20260121202212.4438-3-zhiw@nvidia.com
[ Add #[expect(unused)] to define_{read,write}!(). - Danilo ]
Signed-off-by: Danilo Krummrich

rust: io: always inline functions using build_assert with arguments

2026-01-14T19:30:26+00:00

`build_assert` relies on the compiler to optimize out its error path.
Functions using it with its arguments must thus always be inlined,
otherwise the error path of `build_assert` might not be optimized out,
triggering a build error.

Cc: stable@vger.kernel.org
Fixes: ce30d94e6855 ("rust: add `io::{Io, IoRaw}` base types")
Reviewed-by: Daniel Almeida 
Signed-off-by: Alexandre Courbot 
Tested-by: Timur Tabi 
Link: https://patch.msgid.link/20251208-io-build-assert-v3-2-98aded02c1ea@nvidia.com
Signed-off-by: Danilo Krummrich

rust: io: remove square brackets from pci::Bar reference

2026-01-06T20:44:58+00:00

Remove square brackets since this section is not a part of doc-comment
so the reference will not be converted to a link in the generated docs.

Suggested-by: Danilo Krummrich 
Signed-off-by: Marko Turk 
Link: https://patch.msgid.link/20260105213726.73000-1-mt@markoturk.info
Signed-off-by: Danilo Krummrich

rust: io: add typedef for phys_addr_t

2025-11-13T09:17:24+00:00

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 
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

rust: io: move ResourceSize to top-level io module

2025-11-13T09:16:51+00:00

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 
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