* [PATCH v7 1/2] rust: input: add input device abstractions
2026-11-07 6:35 [PATCH v7 0/2] rust: input: add input/serio abstractions and port Gravis Stinger driver Vecheslav Filatov
@ 2026-11-07 6:35 ` Vecheslav Filatov
2026-11-07 6:35 ` [PATCH v7 2/2] rust: serio: add serio bus abstractions and port Gravis Stinger driver Vecheslav Filatov
1 sibling, 0 replies; 4+ messages in thread
From: Vecheslav Filatov @ 2026-11-07 6:35 UTC (permalink / raw)
To: ojeda, dmitry.torokhov; +Cc: rust-for-linux, linux-input, Vecheslav Filatov
Add safe Rust abstractions for Linux input devices (struct input_dev).
This provides:
- `AllocatedDevice`: a newly allocated, unregistered input device handle
that allows configuring capabilities (keys, absolute axis limits, parent
device) before registration.
- Safe string methods: `set_name` and `set_phys` accept `&'static CStr`
to prevent use-after-free since the input core does not copy strings.
- `set_phys_from_parent`: dynamic physical location path formatting
("%s/input0") stored safely in an owned kernel heap buffer.
- Device lifecycle and reference count management: `set_parent` takes
a reference count via `bindings::get_device` to avoid dangling pointers,
releasing it appropriately on drop or post-registration.
- Bounds-checked `set_abs_params` validating `axis < ABS_CNT` (0x40)
to prevent memory corruption in `dev->absinfo`.
- `RegisteredDevice`: a registered input device handle providing safe,
inlined methods to report keys, absolute coordinates, and synchronization
events. Automatically calls `input_unregister_device` on drop (RAII).
- Constants for bus types (`bus::*`) and event types (`event_type::*`).
- Alphabetically sorted imports and module entries gated with
`#[cfg(CONFIG_INPUT = "y")]` and `#if IS_REACHABLE(CONFIG_INPUT)`
to avoid link failures when CONFIG_INPUT is disabled or modular.
Signed-off-by: Vecheslav Filatov <harepro29@gmail.com>
---
rust/bindings/bindings_helper.h | 1 +
rust/helpers/helpers.c | 1 +
rust/helpers/input.c | 22 +++
rust/kernel/input.rs | 253 ++++++++++++++++++++++++++++++++
rust/kernel/lib.rs | 2 +
5 files changed, 279 insertions(+)
create mode 100644 rust/helpers/input.c
create mode 100644 rust/kernel/input.rs
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 3791af0aadc7..4b09d3980e10 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -64,6 +64,7 @@
#include <linux/fwctl.h>
#include <linux/fs.h>
#include <linux/i2c.h>
+#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/io-pgtable.h>
#include <linux/ioport.h>
diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
index d62c7be1ca7b..77cec85ad153 100644
--- a/rust/helpers/helpers.c
+++ b/rust/helpers/helpers.c
@@ -67,6 +67,7 @@
#include "fs.c"
#include "fwctl.c"
#include "gpu.c"
+#include "input.c"
#include "interrupt.c"
#include "io.c"
#include "irq.c"
diff --git a/rust/helpers/input.c b/rust/helpers/input.c
new file mode 100644
index 000000000000..f43a06acfdc3
--- /dev/null
+++ b/rust/helpers/input.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/input.h>
+
+#if IS_REACHABLE(CONFIG_INPUT)
+
+__rust_helper void rust_helper_input_report_key(struct input_dev *dev, unsigned int code, int value)
+{
+ input_report_key(dev, code, value);
+}
+
+__rust_helper void rust_helper_input_report_abs(struct input_dev *dev, unsigned int code, int value)
+{
+ input_report_abs(dev, code, value);
+}
+
+__rust_helper void rust_helper_input_sync(struct input_dev *dev)
+{
+ input_sync(dev);
+}
+
+#endif /* IS_REACHABLE(CONFIG_INPUT) */
diff --git a/rust/kernel/input.rs b/rust/kernel/input.rs
new file mode 100644
index 000000000000..14977298ad47
--- /dev/null
+++ b/rust/kernel/input.rs
@@ -0,0 +1,253 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Input subsystem abstractions for safe Rust drivers.
+//!
+//! Provides a safe Rust object-oriented interface around Linux `struct input_dev`,
+//! ensuring safe allocation, capability configuration, registration, and RAII cleanup.
+
+use crate::{
+ bindings, //
+ device, //
+ error::to_result, //
+ prelude::*, //
+};
+use core::ptr::NonNull;
+
+/// Bus types for input devices.
+pub mod bus {
+ use super::*;
+
+ /// PCI bus.
+ pub const PCI: u16 = bindings::BUS_PCI as u16;
+ /// USB bus.
+ pub const USB: u16 = bindings::BUS_USB as u16;
+ /// RS232 serial bus.
+ pub const RS232: u16 = bindings::BUS_RS232 as u16;
+}
+
+/// Event types reported by input devices.
+pub mod event_type {
+ use super::*;
+
+ /// Key or button press/release events.
+ pub const KEY: u32 = bindings::EV_KEY;
+ /// Absolute axis movement events.
+ pub const ABS: u32 = bindings::EV_ABS;
+}
+
+/// An allocated input device being configured prior to registration.
+pub struct AllocatedDevice {
+ ptr: NonNull<bindings::input_dev>,
+ phys: Option<KBox<[u8; 64]>>,
+}
+
+impl AllocatedDevice {
+ /// Allocates a new input device.
+ #[inline]
+ pub fn new() -> Result<Self> {
+ // SAFETY: `input_allocate_device` returns either a valid pointer or NULL.
+ let ptr = unsafe { bindings::input_allocate_device() };
+ let ptr = NonNull::new(ptr).ok_or(ENOMEM)?;
+
+ Ok(Self { ptr, phys: None })
+ }
+
+ /// Sets the human-readable device name.
+ #[inline]
+ pub fn set_name(&mut self, name: &'static CStr) {
+ // SAFETY: `self.ptr` is valid and `name` has static lifetime.
+ unsafe {
+ (*self.ptr.as_ptr()).name = name.as_char_ptr().cast();
+ }
+ }
+
+ /// Sets the physical location string from a static C string.
+ #[inline]
+ pub fn set_phys(&mut self, phys: &'static CStr) {
+ // SAFETY: `self.ptr` is valid and `phys` has static lifetime.
+ unsafe {
+ (*self.ptr.as_ptr()).phys = phys.as_char_ptr().cast();
+ }
+ }
+
+ /// Sets the physical location string by formatting `<parent_phys>/input0`.
+ #[inline]
+ pub fn set_phys_from_parent(&mut self, parent_phys: &[u8]) -> Result {
+ let mut buf = KBox::new([0u8; 64], GFP_KERNEL)?;
+ let len = parent_phys
+ .iter()
+ .position(|&b| b == 0)
+ .unwrap_or(parent_phys.len());
+ let suffix = b"/input0\0";
+ if len + suffix.len() > buf.len() {
+ return Err(EINVAL);
+ }
+ buf[..len].copy_from_slice(&parent_phys[..len]);
+ buf[len..len + suffix.len()].copy_from_slice(suffix);
+
+ // SAFETY: `buf` is allocated on the kernel heap and its lifetime is tied to `self.phys`.
+ unsafe {
+ (*self.ptr.as_ptr()).phys = buf.as_ptr().cast();
+ }
+ self.phys = Some(buf);
+ Ok(())
+ }
+
+ /// Sets device identifier (bus type, vendor, product, version).
+ #[inline]
+ pub fn set_id(&mut self, bustype: u16, vendor: u16, product: u16, version: u16) {
+ // SAFETY: `self.ptr` is valid.
+ unsafe {
+ let dev = self.ptr.as_ptr();
+ (*dev).id.bustype = bustype;
+ (*dev).id.vendor = vendor;
+ (*dev).id.product = product;
+ (*dev).id.version = version;
+ }
+ }
+
+ /// Sets the parent device for this input device.
+ ///
+ /// Holds a reference count on `parent` to prevent dangling pointers before registration.
+ #[inline]
+ pub fn set_parent(&mut self, parent: &device::Device) {
+ // SAFETY: `self.ptr` is valid, and `parent.as_raw()` returns a valid `struct device`.
+ // Acquire a reference to guarantee `parent` remains alive while referenced by `dev.parent`.
+ unsafe {
+ let old = (*self.ptr.as_ptr()).dev.parent;
+ if !old.is_null() {
+ bindings::put_device(old);
+ }
+ (*self.ptr.as_ptr()).dev.parent = bindings::get_device(parent.as_raw());
+ }
+ }
+
+ /// Enables support for a capability (e.g. key or axis).
+ #[inline]
+ pub fn set_capability(&mut self, type_: u32, code: u32) {
+ // SAFETY: `self.ptr` is valid and type/code are valid capability values.
+ unsafe {
+ bindings::input_set_capability(self.ptr.as_ptr(), type_, code);
+ }
+ }
+
+ /// Sets parameter limits for an absolute axis.
+ ///
+ /// Bounds-checks `axis < ABS_CNT` (0x40) to prevent out-of-bounds writes
+ /// to the `absinfo` array in `struct input_dev`.
+ #[inline]
+ pub fn set_abs_params(
+ &mut self,
+ axis: u32,
+ min: i32,
+ max: i32,
+ fuzz: i32,
+ flat: i32,
+ ) -> Result {
+ if axis >= bindings::ABS_CNT {
+ return Err(EINVAL);
+ }
+
+ // SAFETY: `self.ptr` is valid and `axis` has been verified within bounds.
+ unsafe {
+ bindings::input_set_abs_params(self.ptr.as_ptr(), axis, min, max, fuzz, flat);
+ }
+ Ok(())
+ }
+
+ /// Registers the input device with the kernel input core.
+ ///
+ /// Consumes the `AllocatedDevice` and returns a [`RegisteredDevice`].
+ #[inline]
+ pub fn register(mut self) -> Result<RegisteredDevice> {
+ // SAFETY: `ptr` is valid and was allocated by `input_allocate_device`.
+ to_result(unsafe { bindings::input_register_device(self.ptr.as_ptr()) })?;
+
+ // SAFETY: `device_add` during `input_register_device` acquires its own reference
+ // to `parent`, so we drop our pre-registration reference to avoid a leak.
+ unsafe {
+ let parent = (*self.ptr.as_ptr()).dev.parent;
+ if !parent.is_null() {
+ bindings::put_device(parent);
+ }
+ }
+
+ let ptr = self.ptr;
+ let phys = self.phys.take();
+ core::mem::forget(self);
+
+ Ok(RegisteredDevice { ptr, _phys: phys })
+ }
+}
+
+impl Drop for AllocatedDevice {
+ #[inline]
+ fn drop(&mut self) {
+ // SAFETY: `self.ptr` was allocated by `input_allocate_device` and has not been registered.
+ unsafe {
+ let parent = (*self.ptr.as_ptr()).dev.parent;
+ if !parent.is_null() {
+ bindings::put_device(parent);
+ }
+ bindings::input_free_device(self.ptr.as_ptr());
+ }
+ }
+}
+
+// SAFETY: `AllocatedDevice` exclusively owns its `input_dev` pointer and can be transferred
+// across threads.
+unsafe impl Send for AllocatedDevice {}
+// SAFETY: `AllocatedDevice` has exclusive ownership and thread-safe methods.
+unsafe impl Sync for AllocatedDevice {}
+
+/// A registered input device capable of reporting events to userspace.
+pub struct RegisteredDevice {
+ ptr: NonNull<bindings::input_dev>,
+ _phys: Option<KBox<[u8; 64]>>,
+}
+
+impl RegisteredDevice {
+ /// Reports a binary button or key state event.
+ #[inline]
+ pub fn report_key(&self, code: u32, value: bool) {
+ // SAFETY: `self.ptr` is valid and registered with the input core.
+ unsafe {
+ bindings::input_report_key(self.ptr.as_ptr(), code, if value { 1 } else { 0 });
+ }
+ }
+
+ /// Reports an absolute axis position value.
+ #[inline]
+ pub fn report_abs(&self, code: u32, value: i32) {
+ // SAFETY: `self.ptr` is valid and registered with the input core.
+ unsafe {
+ bindings::input_report_abs(self.ptr.as_ptr(), code, value);
+ }
+ }
+
+ /// Flushes and synchronizes all reported events into a single input packet.
+ #[inline]
+ pub fn sync(&self) {
+ // SAFETY: `self.ptr` is valid and registered with the input core.
+ unsafe {
+ bindings::input_sync(self.ptr.as_ptr());
+ }
+ }
+}
+
+impl Drop for RegisteredDevice {
+ #[inline]
+ fn drop(&mut self) {
+ // SAFETY: `self.ptr` was successfully registered with `input_register_device`.
+ // Unregistering automatically unbinds and frees the device.
+ unsafe {
+ bindings::input_unregister_device(self.ptr.as_ptr());
+ }
+ }
+}
+
+// SAFETY: `RegisteredDevice` can be safely transferred across threads.
+unsafe impl Send for RegisteredDevice {}
+// SAFETY: Event reporting on `input_dev` is thread-safe (protected by internal locks in the
+// input core).
+unsafe impl Sync for RegisteredDevice {}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 1ab41129d557..ff5c978758d0 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -88,6 +88,8 @@
#[doc(hidden)]
pub mod impl_flags;
pub mod init;
+#[cfg(CONFIG_INPUT = "y")]
+pub mod input;
pub mod interop;
pub mod interrupt;
pub mod io;
--
2.56.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v7 2/2] rust: serio: add serio bus abstractions and port Gravis Stinger driver
2026-11-07 6:35 [PATCH v7 0/2] rust: input: add input/serio abstractions and port Gravis Stinger driver Vecheslav Filatov
2026-11-07 6:35 ` [PATCH v7 1/2] rust: input: add input device abstractions Vecheslav Filatov
@ 2026-11-07 6:35 ` Vecheslav Filatov
2026-11-07 6:50 ` sashiko-bot
1 sibling, 1 reply; 4+ messages in thread
From: Vecheslav Filatov @ 2026-11-07 6:35 UTC (permalink / raw)
To: ojeda, dmitry.torokhov; +Cc: rust-for-linux, linux-input, Vecheslav Filatov
Add safe Rust abstractions for the serio (Serial I/O) bus subsystem and
port the legacy Gravis Stinger serial gamepad driver to safe Rust.
This introduces:
- DeviceId: a transparent wrapper around struct serio_device_id
implementing RawDeviceId for type-safe matching tables.
- IdTable and serio_device_table! macro: guarantees a zero sentinel
termination entry at compile time and creates modpost device aliases.
- Device: a serio port device instance implementing AsBusDevice,
impl_device_context_deref!, and AsRef<device::Device>.
- Port lifecycle & interrupt race protection: T::init initializes
driver state and allocates input devices, storing drvdata BEFORE
serio_open() opens the hardware port. T::start publishes child
devices only after serio_open() succeeds, and T::attach safely
binds them under serio_pause_rx with bounded borrow_mut lifetime.
- IrqReturn mapping: directly returns bindings::irqreturn_IRQ_*
constants without constructor calls or UB.
- Driver trait: safe interface for serio drivers (init, start,
attach, interrupt, disconnect).
- Registration<T>: safe RAII registration adapter that stores
Opaque<bindings::serio_driver> inside Pin<KBox<...>> and calls
__serio_register_driver with the caller's &'static ThisModule
to correctly track module ownership.
- stinger_rust: port of the Gravis Stinger serial gamepad driver in
safe Rust (drivers/input/joystick/stinger_rust.rs), containing zero
unsafe blocks, preserving the userspace device name ("Gravis Stinger")
for udev/EVIOCGNAME, dynamically formatting phys paths ("%s/input0"),
and compiling as the standard stinger.ko module name with crate-name
stinger for correct builtin modalias.
- Non-regression Kconfig: adds CONFIG_JOYSTICK_STINGER_RUST guarded on
RUST && SERIO=y && INPUT=y while retaining the original C driver
(stinger.c) to maintain hardware support on non-Rust configurations
and architectures without HAVE_RUST.
- Gated module entry #[cfg(CONFIG_SERIO = "y")] and helper guards
#if IS_REACHABLE(CONFIG_SERIO) to avoid undefined symbols when serio
is disabled or modular.
Signed-off-by: Vecheslav Filatov <harepro29@gmail.com>
---
drivers/input/joystick/Kconfig | 14 +
drivers/input/joystick/Makefile | 4 +
drivers/input/joystick/stinger_rust.rs | 191 ++++++++++++++
rust/bindings/bindings_helper.h | 1 +
rust/helpers/helpers.c | 1 +
rust/helpers/serio.c | 27 ++
rust/kernel/lib.rs | 2 +
rust/kernel/serio.rs | 341 +++++++++++++++++++++++++
8 files changed, 581 insertions(+)
create mode 100644 drivers/input/joystick/stinger_rust.rs
create mode 100644 rust/helpers/serio.c
create mode 100644 rust/kernel/serio.rs
diff --git a/drivers/input/joystick/Kconfig b/drivers/input/joystick/Kconfig
index 7755e5b454d2..89cc1dd9d865 100644
--- a/drivers/input/joystick/Kconfig
+++ b/drivers/input/joystick/Kconfig
@@ -197,6 +197,20 @@ config JOYSTICK_STINGER
To compile this driver as a module, choose M here: the
module will be called stinger.
+config JOYSTICK_STINGER_RUST
+ bool "Safe Rust implementation of Gravis Stinger gamepad driver"
+ depends on JOYSTICK_STINGER
+ depends on RUST && SERIO = y && INPUT = y
+ default y
+ help
+ Say Y here to use the safe Rust rewrite of the Gravis Stinger
+ gamepad driver instead of the legacy C implementation.
+
+ The Rust driver provides memory safety guarantees while preserving
+ full hardware protocol compatibility.
+
+ If unsure, say Y.
+
config JOYSTICK_TWIDJOY
tristate "Twiddler as a joystick"
select SERIO
diff --git a/drivers/input/joystick/Makefile b/drivers/input/joystick/Makefile
index 9976f596a920..f5101ced0b6c 100644
--- a/drivers/input/joystick/Makefile
+++ b/drivers/input/joystick/Makefile
@@ -33,6 +33,10 @@ obj-$(CONFIG_JOYSTICK_SENSEHAT) += sensehat-joystick.o
obj-$(CONFIG_JOYSTICK_SIDEWINDER) += sidewinder.o
obj-$(CONFIG_JOYSTICK_SPACEBALL) += spaceball.o
obj-$(CONFIG_JOYSTICK_SPACEORB) += spaceorb.o
+ifdef CONFIG_JOYSTICK_STINGER_RUST
+RUSTFLAGS_stinger_rust.o := --crate-name stinger
+stinger-objs := stinger_rust.o
+endif
obj-$(CONFIG_JOYSTICK_STINGER) += stinger.o
obj-$(CONFIG_JOYSTICK_TMDC) += tmdc.o
obj-$(CONFIG_JOYSTICK_TURBOGRAFX) += turbografx.o
diff --git a/drivers/input/joystick/stinger_rust.rs b/drivers/input/joystick/stinger_rust.rs
new file mode 100644
index 000000000000..af78524fadcf
--- /dev/null
+++ b/drivers/input/joystick/stinger_rust.rs
@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Gravis Stinger gamepad driver written in safe Rust.
+//!
+//! Rust port of legacy C driver `drivers/input/joystick/stinger.c`.
+//!
+//! Authors:
+//! - Original C driver: Vojtech Pavlik <vojtech@ucw.cz>, Mark Fletcher
+//! - Rust port: Rust for Linux Contributors
+
+use kernel::{
+ bindings, //
+ device, //
+ input::{
+ bus, //
+ event_type, //
+ AllocatedDevice, //
+ RegisteredDevice, //
+ }, //
+ prelude::*, //
+ serio::{
+ self, //
+ IrqReturn, //
+ }, //
+ types::ForeignOwnable, //
+};
+
+const DRIVER_NAME: &CStr = c"stinger";
+const DRIVER_DESC: &CStr = c"Gravis Stinger";
+const DRIVER_SERIO_DESC: &CStr = c"Gravis Stinger gamepad driver";
+
+const STINGER_MAX_LENGTH: usize = 8;
+
+kernel::serio_device_table!(
+ STINGER_IDS,
+ [serio::DeviceId::new(
+ bindings::SERIO_RS232 as u8,
+ bindings::SERIO_ANY as u8,
+ bindings::SERIO_ANY as u8,
+ bindings::SERIO_STINGER as u8,
+ )]
+);
+
+/// Per-device state for an attached Gravis Stinger gamepad.
+struct Stinger {
+ input: Option<RegisteredDevice>,
+ idx: usize,
+ data: [u8; STINGER_MAX_LENGTH],
+}
+
+impl Stinger {
+ /// Decodes incoming 4-byte packets from the Gravis Stinger and reports input events.
+ fn process_packet(&self) {
+ let Some(input) = self.input.as_ref() else {
+ return;
+ };
+
+ if self.idx == 0 {
+ return;
+ }
+
+ let d0 = i32::from(self.data[0]);
+ let d1 = i32::from(self.data[1]);
+ let d2 = i32::from(self.data[2]);
+ let d3 = i32::from(self.data[3]);
+
+ // Report button states (active high bits in packet)
+ input.report_key(bindings::BTN_A, ((d0 & 0x20) >> 5) != 0);
+ input.report_key(bindings::BTN_B, ((d0 & 0x10) >> 4) != 0);
+ input.report_key(bindings::BTN_C, ((d0 & 0x08) >> 3) != 0);
+ input.report_key(bindings::BTN_X, ((d0 & 0x04) >> 2) != 0);
+ input.report_key(bindings::BTN_Y, ((d3 & 0x20) >> 5) != 0);
+ input.report_key(bindings::BTN_Z, ((d3 & 0x10) >> 4) != 0);
+ input.report_key(bindings::BTN_TL, ((d3 & 0x08) >> 3) != 0);
+ input.report_key(bindings::BTN_TR, ((d3 & 0x04) >> 2) != 0);
+ input.report_key(bindings::BTN_SELECT, ((d3 & 0x02) >> 1) != 0);
+ input.report_key(bindings::BTN_START, (d3 & 0x01) != 0);
+
+ // Report 2-axis position: coordinates in range -64..64
+ input.report_abs(bindings::ABS_X, (d1 & 0x3f) - ((d0 & 0x01) << 6));
+ input.report_abs(bindings::ABS_Y, ((d0 & 0x02) << 5) - (d2 & 0x3f));
+
+ input.sync();
+ }
+}
+
+/// Serio driver implementation for Gravis Stinger gamepad.
+struct StingerDriver;
+
+impl serio::Driver for StingerDriver {
+ type Data = KBox<Stinger>;
+ type Pending = AllocatedDevice;
+ type Published = RegisteredDevice;
+
+ const ID_TABLE: serio::IdTable = &STINGER_IDS;
+
+ fn init(dev: &serio::Device<device::Bound>) -> Result<(Self::Data, Self::Pending)> {
+ let mut input_alloc = AllocatedDevice::new()?;
+
+ input_alloc.set_name(DRIVER_DESC);
+ input_alloc.set_id(bus::RS232, bindings::SERIO_STINGER as u16, 0x0001, 0x0100);
+ input_alloc.set_parent(dev.as_ref());
+ input_alloc.set_phys_from_parent(dev.phys())?;
+
+ // Configure supported buttons
+ for btn in [
+ bindings::BTN_A,
+ bindings::BTN_B,
+ bindings::BTN_C,
+ bindings::BTN_X,
+ bindings::BTN_Y,
+ bindings::BTN_Z,
+ bindings::BTN_TL,
+ bindings::BTN_TR,
+ bindings::BTN_START,
+ bindings::BTN_SELECT,
+ ] {
+ input_alloc.set_capability(event_type::KEY, btn);
+ }
+
+ // Configure 2-axis analog input
+ input_alloc.set_abs_params(bindings::ABS_X, -64, 64, 0, 4)?;
+ input_alloc.set_abs_params(bindings::ABS_Y, -64, 64, 0, 4)?;
+
+ let stinger = KBox::new(
+ Stinger {
+ input: None,
+ idx: 0,
+ data: [0; STINGER_MAX_LENGTH],
+ },
+ GFP_KERNEL,
+ )?;
+
+ Ok((stinger, input_alloc))
+ }
+
+ fn start(pending: Self::Pending) -> Result<Self::Published> {
+ pending.register()
+ }
+
+ fn attach(
+ stinger: &mut <Self::Data as ForeignOwnable>::BorrowedMut<'_>,
+ published: Self::Published,
+ ) {
+ stinger.input = Some(published);
+ }
+
+ fn interrupt(
+ stinger: &mut <Self::Data as ForeignOwnable>::BorrowedMut<'_>,
+ data: u8,
+ _flags: u32,
+ ) -> IrqReturn {
+ if stinger.idx < STINGER_MAX_LENGTH {
+ stinger.data[stinger.idx] = data;
+ stinger.idx += 1;
+ }
+
+ if stinger.idx == 4 {
+ stinger.process_packet();
+ stinger.idx = 0;
+ }
+
+ IrqReturn::Handled
+ }
+
+ #[inline]
+ fn disconnect(_data: Self::Data) {
+ // Automatically drops `stinger`, unregistering and freeing the input device.
+ }
+}
+
+module! {
+ type: StingerModule,
+ name: "stinger",
+ authors: ["Rust for Linux Contributors"],
+ description: "Gravis Stinger gamepad driver in safe Rust",
+ license: "GPL",
+}
+
+struct StingerModule {
+ _reg: serio::Registration<StingerDriver>,
+}
+
+impl kernel::Module for StingerModule {
+ fn init(module: &'static ThisModule) -> Result<Self> {
+ let reg =
+ serio::Registration::<StingerDriver>::new(DRIVER_NAME, DRIVER_SERIO_DESC, module)?;
+ pr_info!("Gravis Stinger safe Rust driver initialized\n");
+ Ok(Self { _reg: reg })
+ }
+}
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 4b09d3980e10..0e44af5d770c 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -89,6 +89,7 @@
#include <linux/sched.h>
#include <linux/security.h>
#include <linux/serdev.h>
+#include <linux/serio.h>
#include <linux/slab.h>
#include <linux/sys_soc.h>
#include <linux/task_work.h>
diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
index 77cec85ad153..61cf3f77e85a 100644
--- a/rust/helpers/helpers.c
+++ b/rust/helpers/helpers.c
@@ -96,6 +96,7 @@
#include "scatterlist.c"
#include "security.c"
#include "serdev.c"
+#include "serio.c"
#include "signal.c"
#include "slab.c"
#include "spinlock.c"
diff --git a/rust/helpers/serio.c b/rust/helpers/serio.c
new file mode 100644
index 000000000000..f88b6c2a900b
--- /dev/null
+++ b/rust/helpers/serio.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/serio.h>
+
+#if IS_REACHABLE(CONFIG_SERIO)
+
+__rust_helper void *rust_helper_serio_get_drvdata(struct serio *serio)
+{
+ return serio_get_drvdata(serio);
+}
+
+__rust_helper void rust_helper_serio_set_drvdata(struct serio *serio, void *data)
+{
+ serio_set_drvdata(serio, data);
+}
+
+__rust_helper void rust_helper_serio_pause_rx(struct serio *serio)
+{
+ serio_pause_rx(serio);
+}
+
+__rust_helper void rust_helper_serio_continue_rx(struct serio *serio)
+{
+ serio_continue_rx(serio);
+}
+
+#endif /* IS_REACHABLE(CONFIG_SERIO) */
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index ff5c978758d0..711b7ef06b57 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -134,6 +134,8 @@
pub mod seq_file;
#[cfg(CONFIG_RUST_SERIAL_DEV_BUS_ABSTRACTIONS)]
pub mod serdev;
+#[cfg(CONFIG_SERIO = "y")]
+pub mod serio;
pub mod sizes;
#[cfg(CONFIG_SOC_BUS)]
pub mod soc;
diff --git a/rust/kernel/serio.rs b/rust/kernel/serio.rs
new file mode 100644
index 000000000000..dc0de5f52715
--- /dev/null
+++ b/rust/kernel/serio.rs
@@ -0,0 +1,341 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Serio (Serial I/O) bus abstractions for safe Rust drivers.
+//!
+//! Provides a safe Rust interface for serio devices and drivers in the Linux kernel,
+//! supporting input devices such as serial gamepads (e.g. Gravis Stinger), mice, and keyboards.
+
+use crate::{
+ device, //
+ device_id::{
+ IdTable as GenericIdTable, //
+ RawDeviceId, //
+ }, //
+ error::{
+ to_result, //
+ Result, //
+ }, //
+ ffi::{
+ c_int, //
+ c_uchar, //
+ c_uint, //
+ }, //
+ prelude::*, //
+ types::{
+ ForeignOwnable, //
+ Opaque, //
+ }, //
+ ThisModule, //
+};
+use core::{
+ marker::PhantomData, //
+ pin::Pin, //
+};
+
+mod bindings {
+ pub(super) use crate::bindings::*;
+
+ #[allow(non_upper_case_globals)]
+ pub(super) const irqreturn_IRQ_NONE: crate::bindings::irqreturn_t =
+ crate::bindings::irqreturn::IRQ_NONE;
+ #[allow(non_upper_case_globals)]
+ pub(super) const irqreturn_IRQ_HANDLED: crate::bindings::irqreturn_t =
+ crate::bindings::irqreturn::IRQ_HANDLED;
+}
+
+pub use crate::irq::IrqReturn;
+
+/// Identifies supported serio hardware devices for auto-probing and matching.
+#[repr(transparent)]
+#[derive(Copy, Clone)]
+pub struct DeviceId(bindings::serio_device_id);
+
+impl DeviceId {
+ /// Creates a new serio device identifier.
+ #[inline]
+ pub const fn new(type_: u8, extra: u8, id: u8, proto: u8) -> Self {
+ Self(bindings::serio_device_id {
+ type_,
+ extra,
+ id,
+ proto,
+ })
+ }
+}
+
+// SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper around `bindings::serio_device_id`.
+unsafe impl RawDeviceId for DeviceId {
+ type RawType = bindings::serio_device_id;
+}
+
+/// Type alias for serio device ID tables.
+pub type IdTable = &'static dyn GenericIdTable<DeviceId, ()>;
+
+/// Creates a serio device table with a zero sentinel for module autoloading and matching.
+#[macro_export]
+macro_rules! serio_device_table {
+ ($table_name:ident, [$($id:expr),* $(,)?]) => {
+ $crate::module_device_table!(
+ "serio",
+ $crate::serio::DeviceId,
+ $table_name,
+ @none,
+ [$($id),*]
+ );
+ };
+}
+
+/// A serio port device instance passed to driver callbacks.
+#[repr(transparent)]
+pub struct Device<Ctx: device::DeviceContext = device::Normal>(
+ Opaque<bindings::serio>,
+ PhantomData<Ctx>,
+);
+
+impl<Ctx: device::DeviceContext> Device<Ctx> {
+ /// Returns the raw pointer to the underlying `struct serio`.
+ #[inline]
+ pub(crate) fn as_raw(&self) -> *mut bindings::serio {
+ self.0.get()
+ }
+
+ /// Reads the physical device path into a buffer.
+ #[inline]
+ pub fn phys(&self) -> &[u8; 32] {
+ // SAFETY: `self.as_raw()` points to a valid `struct serio`.
+ unsafe { &(*self.as_raw()).phys }
+ }
+}
+
+// SAFETY: `serio::Device` is a transparent wrapper of `struct serio`.
+// The offset is guaranteed to point to a valid device field inside `serio::Device`.
+unsafe impl<Ctx: device::DeviceContext> device::AsBusDevice<Ctx> for Device<Ctx> {
+ const OFFSET: usize = core::mem::offset_of!(bindings::serio, dev);
+}
+
+kernel::impl_device_context_deref!(unsafe { Device });
+
+impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> {
+ #[inline]
+ fn as_ref(&self) -> &device::Device<Ctx> {
+ // SAFETY: By the type invariant of `Self`, `self.as_raw()` is a pointer to a valid
+ // `struct serio`.
+ let dev = unsafe { core::ptr::addr_of_mut!((*self.as_raw()).dev) };
+
+ // SAFETY: `dev` points to a valid `struct device`.
+ unsafe { device::Device::from_raw(dev) }
+ }
+}
+
+/// Trait implemented by serio device drivers.
+pub trait Driver: Send + Sync + Sized {
+ /// Context data stored per connected device instance.
+ type Data: ForeignOwnable + Send + Sync;
+
+ /// Pending resources allocated during probe to be published after the port opens.
+ type Pending;
+
+ /// Published device handle created after the port opens.
+ type Published;
+
+ /// Device ID match table.
+ const ID_TABLE: IdTable;
+
+ /// Initializes driver data before the port is opened.
+ fn init(dev: &Device<device::Bound>) -> Result<(Self::Data, Self::Pending)>;
+
+ /// Registers/publishes child devices in process context after `serio_open` succeeds.
+ fn start(pending: Self::Pending) -> Result<Self::Published>;
+
+ /// Attaches the published child device under `serio_pause_rx` to eliminate races.
+ fn attach(
+ data: &mut <Self::Data as ForeignOwnable>::BorrowedMut<'_>,
+ published: Self::Published,
+ );
+
+ /// Called in interrupt context when a new byte arrives from the serio port.
+ fn interrupt(
+ data: &mut <Self::Data as ForeignOwnable>::BorrowedMut<'_>,
+ byte: u8,
+ flags: u32,
+ ) -> IrqReturn;
+
+ /// Called when the device is disconnected.
+ #[inline]
+ fn disconnect(_data: Self::Data) {}
+}
+
+/// Driver adapter that bridges the safe Rust [`Driver`] trait to the C serio bus subsystem.
+pub struct Registration<T: Driver> {
+ drv: Pin<KBox<Opaque<bindings::serio_driver>>>,
+ _p: PhantomData<T>,
+}
+
+impl<T: Driver> Registration<T> {
+ /// Registers a serio driver with the kernel.
+ pub fn new(
+ name: &'static CStr,
+ description: &'static CStr,
+ module: &'static ThisModule,
+ ) -> Result<Self> {
+ let drv = bindings::serio_driver {
+ description: description.as_char_ptr(),
+ id_table: T::ID_TABLE.as_ptr(),
+ manual_bind: false,
+ write_wakeup: None,
+ interrupt: Some(Self::interrupt_callback),
+ connect: Some(Self::connect_callback),
+ reconnect: None,
+ fast_reconnect: None,
+ disconnect: Some(Self::disconnect_callback),
+ cleanup: None,
+ driver: bindings::device_driver {
+ name: name.as_char_ptr(),
+ ..Default::default()
+ },
+ };
+
+ let drv_box = KBox::into_pin(KBox::new(Opaque::new(drv), GFP_KERNEL)?);
+
+ // SAFETY: `drv_box` is pinned on the kernel heap at a permanent address.
+ // `module` and `name` are valid static references.
+ let ret = unsafe {
+ bindings::__serio_register_driver(drv_box.get(), module.as_ptr(), name.as_char_ptr())
+ };
+ to_result(ret)?;
+
+ Ok(Self {
+ drv: drv_box,
+ _p: PhantomData,
+ })
+ }
+
+ /// # Safety
+ ///
+ /// Must only be invoked by the serio subsystem when a matching port is probed.
+ /// `serio` and `drv` must be valid non-null pointers provided by the kernel.
+ unsafe extern "C" fn connect_callback(
+ serio: *mut bindings::serio,
+ drv: *mut bindings::serio_driver,
+ ) -> c_int {
+ if serio.is_null() {
+ return crate::error::code::EINVAL.to_errno();
+ }
+
+ // SAFETY: `serio` is valid. `Device<Bound>` is repr(transparent).
+ let dev = unsafe { &*(serio.cast::<Device<device::Bound>>()) };
+
+ // 1. Initialize driver data before port is opened.
+ let (data, pending) = match T::init(dev) {
+ Ok(d) => d,
+ Err(e) => return e.to_errno(),
+ };
+
+ let raw_data = data.into_foreign();
+
+ // 2. Set drvdata BEFORE opening port so interrupts never encounter NULL.
+ // SAFETY: `serio` is valid; store driver data pointer.
+ unsafe {
+ bindings::serio_set_drvdata(serio, raw_data.cast());
+ }
+
+ // 3. Open serio port.
+ // SAFETY: `serio` and `drv` are valid non-null pointers provided by the kernel.
+ let ret = unsafe { bindings::serio_open(serio, drv) };
+ if ret != 0 {
+ // SAFETY: Clean up drvdata if open failed.
+ unsafe {
+ bindings::serio_set_drvdata(serio, core::ptr::null_mut());
+ let data = <T::Data as ForeignOwnable>::from_foreign(raw_data);
+ T::disconnect(data);
+ }
+ return ret;
+ }
+
+ // 4. Publish child devices in process context now that port is successfully opened.
+ let published = match T::start(pending) {
+ Ok(p) => p,
+ Err(e) => {
+ // SAFETY: Close port and clean up if device publication failed.
+ unsafe {
+ bindings::serio_close(serio);
+ bindings::serio_set_drvdata(serio, core::ptr::null_mut());
+ let data = <T::Data as ForeignOwnable>::from_foreign(raw_data);
+ T::disconnect(data);
+ }
+ return e.to_errno();
+ }
+ };
+
+ // 5. Attach published resources under `serio_pause_rx` to eliminate races with interrupts.
+ // SAFETY: `serio_pause_rx` holds `serio->lock`, preventing concurrent interrupt execution.
+ unsafe {
+ bindings::serio_pause_rx(serio);
+ {
+ let mut borrowed = <T::Data as ForeignOwnable>::borrow_mut(raw_data);
+ T::attach(&mut borrowed, published);
+ }
+ bindings::serio_continue_rx(serio);
+ }
+
+ 0
+ }
+
+ /// # Safety
+ ///
+ /// Must only be invoked by the serio subsystem during an interrupt on a connected port.
+ /// `serio` must be a valid pointer.
+ unsafe extern "C" fn interrupt_callback(
+ serio: *mut bindings::serio,
+ data: c_uchar,
+ flags: c_uint,
+ ) -> bindings::irqreturn_t {
+ // SAFETY: `serio` is valid.
+ let raw = unsafe { bindings::serio_get_drvdata(serio) };
+ if raw.is_null() {
+ return bindings::irqreturn_IRQ_NONE;
+ }
+
+ // SAFETY: `raw` was created via `into_foreign()` in `connect_callback`.
+ let mut borrowed = unsafe { <T::Data as ForeignOwnable>::borrow_mut(raw) };
+ match T::interrupt(&mut borrowed, data, flags) {
+ IrqReturn::None => bindings::irqreturn_IRQ_NONE,
+ IrqReturn::Handled => bindings::irqreturn_IRQ_HANDLED,
+ }
+ }
+
+ /// # Safety
+ ///
+ /// Must only be invoked by the serio subsystem when disconnecting a port.
+ /// `serio` must be a valid pointer.
+ unsafe extern "C" fn disconnect_callback(serio: *mut bindings::serio) {
+ // SAFETY: `serio` is valid.
+ let raw = unsafe { bindings::serio_get_drvdata(serio) };
+ if raw.is_null() {
+ return;
+ }
+
+ // SAFETY: Close port, clear drvdata, and pass owned data back to disconnect.
+ unsafe {
+ bindings::serio_close(serio);
+ bindings::serio_set_drvdata(serio, core::ptr::null_mut());
+ let data = <T::Data as ForeignOwnable>::from_foreign(raw);
+ T::disconnect(data);
+ }
+ }
+}
+
+impl<T: Driver> Drop for Registration<T> {
+ #[inline]
+ fn drop(&mut self) {
+ // SAFETY: Unregister driver with kernel. `self.drv` is valid and registered.
+ unsafe {
+ bindings::serio_unregister_driver(self.drv.get());
+ }
+ }
+}
+
+// SAFETY: `Registration` can be safely sent to another thread.
+unsafe impl<T: Driver> Send for Registration<T> {}
+// SAFETY: `Registration` can be safely shared across threads.
+unsafe impl<T: Driver> Sync for Registration<T> {}
--
2.56.0
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