linux.git/rust/kernel/io/mem.rs, branch v7.2-rc2

rust: io: make IoMem and ExclusiveIoMem lifetime-parameterized

2026-05-27T14:24:28+00:00

Add a lifetime parameter to IoMem<'a, SIZE> and ExclusiveIoMem<'a,
SIZE>, storing a &'a Device reference to tie the mapping to the
device's lifetime.

This mirrors the pci::Bar<'a, SIZE> design and enables drivers to hold
I/O memory mappings directly in their HRT private data, tied to the
device lifetime.

IoRequest::iomap_* methods now return the mapping directly instead of
wrapping it in Devres. Callers that need device-managed revocation can
call the new into_devres() method.

Acked-by: Uwe Kleine-König 
Reviewed-by: Eliot Courtney 
Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: Alexandre Courbot 
Reviewed-by: Gary Guo 
Link: https://patch.msgid.link/20260525202921.124698-20-dakr@kernel.org
Signed-off-by: Danilo Krummrich

rust: platform: make Driver trait lifetime-parameterized

2026-05-27T14:23:31+00:00

Add a 'bound lifetime to the associated Data, changing type Data to type
Data<'bound>.

This allows the driver's bus device private data to capture the device /
driver bound lifetime; device resources can be stored directly by
reference rather than requiring Devres.

The probe() and unbind() callbacks thus gain a 'bound lifetime parameter
on the methods themselves; avoiding a global lifetime on the trait impl.

Existing drivers set type Data<'bound> = Self, preserving the current
behavior.

Acked-by: Uwe Kleine-König 
Reviewed-by: Alexandre Courbot 
Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: Gary Guo 
Link: https://patch.msgid.link/20260525202921.124698-14-dakr@kernel.org
Signed-off-by: Danilo Krummrich

rust: device: make Core and CoreInternal lifetime-parameterized

2026-05-27T14:22:42+00:00

Device references in probe callbacks are scoped to the callback,
not the full binding duration. Add a lifetime parameter to Core and
CoreInternal to accurately represent this in the type system.

Suggested-by: Gary Guo 
Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: Alexandre Courbot 
Reviewed-by: Eliot Courtney 
Reviewed-by: Gary Guo 
Link: https://patch.msgid.link/20260525202921.124698-12-dakr@kernel.org
Signed-off-by: Danilo Krummrich

rust: driver: decouple driver private data from driver type

2026-05-27T14:22:41+00:00

Add a type Data<'bound> associated type to all bus driver traits,
decoupling the driver's bus device private data type from the driver
struct itself.

In the context of adding a 'bound lifetime, making this an associated
type has the advantage that it allows us to avoid a driver trait global
lifetime and it avoids the need for ForLt for bus device private data;
both of which make the subsequent implementation by buses much simpler.

All existing drivers and doc examples set type Data = Self to preserve
the current behavior.

Reviewed-by: Alexandre Courbot 
Reviewed-by: Gary Guo 
Reviewed-by: Greg Kroah-Hartman 
Link: https://patch.msgid.link/20260525202921.124698-5-dakr@kernel.org
Signed-off-by: Danilo Krummrich

rust: io: mem: use non-relaxed I/O ops in examples

2026-03-17T19:02:09+00:00

The `_relaxed` I/O variant methods are about to be replaced by a wrapper
type exposing this access pattern with the regular methods of the `Io`
trait. Thus replace the examples to use the regular I/O methods.

Since these are examples, we want them to use the most standard ops
anyway, and the relaxed variants were but an addition that was
MMIO-specific.

Reviewed-by: Daniel Almeida 
Acked-by: Alice Ryhl 
Signed-off-by: Alexandre Courbot 
Reviewed-by: Gary Guo 
Link: https://patch.msgid.link/20260206-io-v2-2-71dea20a06e6@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: replace `kernel::c_str!` with C-Strings

2025-12-22T16:30:31+00:00

C-String literals were added in Rust 1.77. Replace instances of
`kernel::c_str!` with C-String literals where possible.

Signed-off-by: Tamir Duberstein 
Reviewed-by: Daniel Almeida 
Link: https://patch.msgid.link/20251222-cstr-driver-core-v1-4-1142a177d0fd@gmail.com
[ Use kernel vertical import style. - Danilo ]
Signed-off-by: Danilo Krummrich

rust: io: cleanup imports and use "kernel vertical" style

2025-11-11T08:43:39+00:00

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 
Link: https://patch.msgid.link/20251104133301.59402-1-dakr@kernel.org
[ Use prelude::* in io/poll.rs. - Danilo ]
Signed-off-by: Danilo Krummrich

rust: driver: let probe() return impl PinInit

2025-10-21T16:40:48+00:00

The driver model defines the lifetime of the private data stored in (and
owned by) a bus device to be valid from when the driver is bound to a
device (i.e. from successful probe()) until the driver is unbound from
the device.

This is already taken care of by the Rust implementation of the driver
model. However, we still ask drivers to return a Result>>
from probe().

Unlike in C, where we do not have the concept of initializers, but
rather deal with uninitialized memory, drivers can just return an
impl PinInit instead.

This contributes to more clarity to the fact that a driver returns it's
device private data in probe() and the Rust driver model owns the data,
manages the lifetime and - considering the lifetime - provides (safe)
accessors for the driver.

Hence, let probe() functions return an impl PinInit instead
of Result>>.

Reviewed-by: Alice Ryhl 
Acked-by: Viresh Kumar 
Reviewed-by: Alexandre Courbot 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Danilo Krummrich

rust: io: fix broken intra-doc links to `platform::Device`

2025-07-22T09:08:59+00:00

`platform` is not accessible from here.

Thus fix the intra-doc links by qualifying the paths a bit more.

Fixes: 1d0d4b28513b ("rust: io: mem: add a generic iomem abstraction")
Signed-off-by: Miguel Ojeda 
Link: https://lore.kernel.org/r/20250722085500.1360401-2-ojeda@kernel.org
Signed-off-by: Danilo Krummrich