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Fri, 06 Nov 2026 11:17:33 -0800 (PST) Received: from DESKTOP-KHFMJSR ([194.9.62.193]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-492d7cc6187sm5224380f8f.46.2026.11.06.11.17.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 Nov 2026 11:17:32 -0800 (PST) From: clicedvly768 To: ojeda@kernel.org, dmitry.torokhov@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-input@vger.kernel.org, clicedvly768 Subject: [PATCH 2/3] rust: serio: add serio bus abstractions Date: Sat, 7 Nov 2026 00:17:13 +0500 Message-ID: <20261106191714.334055-3-harepro29@gmail.com> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261106191714.334055-1-harepro29@gmail.com> References: <20261106191714.334055-1-harepro29@gmail.com> X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add safe Rust abstractions for the serio (Serial I/O) bus subsystem. This introduces: - `DeviceId`: a transparent wrapper around `struct serio_device_id` for device matching tables. - `Device`: a borrowed serio port device passed to driver callbacks. - `IrqReturn`: typed enum for serio interrupt handler status. - `Driver` trait: safe interface for serio drivers (`connect`, `interrupt`, `disconnect`). - `Registration`: safe RAII registration adapter that manages the underlying `struct serio_driver` pinned on the kernel heap, registering it via `serio_register_driver` and unregistering on drop. - C helper wrappers for inline/macro serio functions in . Signed-off-by: clicedvly768 --- rust/bindings/bindings_helper.h | 3 +- rust/helpers/helpers.c | 3 +- rust/helpers/serio.c | 23 ++++ rust/kernel/lib.rs | 3 +- rust/kernel/serio.rs | 223 ++++++++++++++++++++++++++++++++ 5 files changed, 252 insertions(+), 3 deletions(-) create mode 100644 rust/helpers/serio.c create mode 100644 rust/kernel/serio.rs diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index 301c75cfeb61..0e44af5d770c 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -64,6 +64,7 @@ #include #include #include +#include #include #include #include @@ -88,6 +89,7 @@ #include #include #include +#include #include #include #include @@ -171,4 +173,3 @@ const unsigned long RUST_CONST_HELPER_GPU_BUDDY_TRIM_DISABLE = GPU_BUDDY_TRIM_DI #include "../../drivers/android/binder/rust_binder.h" #include "../../drivers/android/binder/rust_binder_events.h" #endif -#include diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index 0bc33a7b4351..61cf3f77e85a 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" @@ -95,6 +96,7 @@ #include "scatterlist.c" #include "security.c" #include "serdev.c" +#include "serio.c" #include "signal.c" #include "slab.c" #include "spinlock.c" @@ -109,4 +111,3 @@ #include "wait.c" #include "workqueue.c" #include "xarray.c" -#include "input.c" diff --git a/rust/helpers/serio.c b/rust/helpers/serio.c new file mode 100644 index 000000000000..cd061495d9b1 --- /dev/null +++ b/rust/helpers/serio.c @@ -0,0 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +__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 int rust_helper_serio_register_driver(struct serio_driver *drv) +{ + return __serio_register_driver(drv, THIS_MODULE, KBUILD_MODNAME); +} + +__rust_helper void rust_helper_serio_unregister_driver(struct serio_driver *drv) +{ + serio_unregister_driver(drv); +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 35cbde5f6a97..e4a4525fafdd 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -88,6 +88,7 @@ #[doc(hidden)] pub mod impl_flags; pub mod init; +pub mod input; pub mod interop; pub mod interrupt; pub mod io; @@ -132,6 +133,7 @@ pub mod seq_file; #[cfg(CONFIG_RUST_SERIAL_DEV_BUS_ABSTRACTIONS)] pub mod serdev; +pub mod serio; pub mod sizes; #[cfg(CONFIG_SOC_BUS)] pub mod soc; @@ -314,4 +316,3 @@ pub fn file_from_location<'a>(loc: &'a core::panic::Location<'a>) -> &'a core::f c"" } } -pub mod input; diff --git a/rust/kernel/serio.rs b/rust/kernel/serio.rs new file mode 100644 index 000000000000..3b752ce4b64d --- /dev/null +++ b/rust/kernel/serio.rs @@ -0,0 +1,223 @@ +// 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::{ + bindings, + error::{to_result, Result}, + prelude::*, + types::ForeignOwnable, +}; +use core::{marker::PhantomData, pin::Pin, ptr::NonNull}; + +/// 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. + pub const fn new(type_: u8, extra: u8, id: u8, proto: u8) -> Self { + Self(bindings::serio_device_id { + type_, + extra, + id, + proto, + }) + } +} + +/// Status returned by a serio driver interrupt handler. +#[derive(Copy, Clone, PartialEq, Eq)] +pub enum IrqReturn { + /// Interrupt was not handled by this driver. + None, + /// Interrupt was successfully handled. + Handled, +} + +impl IrqReturn { + fn to_c(self) -> bindings::irqreturn_t { + match self { + Self::None => bindings::irqreturn::IRQ_NONE, + Self::Handled => bindings::irqreturn::IRQ_HANDLED, + } + } +} + +/// A serio port device instance passed to driver callbacks. +pub struct Device { + ptr: NonNull, +} + +impl Device { + /// Returns the raw pointer to the underlying `struct serio`. + pub fn as_raw(&self) -> *mut bindings::serio { + self.ptr.as_ptr() + } + + /// Reads the physical device path into a buffer. + pub fn phys(&self) -> &[u8; 32] { + // SAFETY: `self.ptr` points to a valid `struct serio`. + unsafe { &(*self.ptr.as_ptr()).phys } + } +} + +/// Trait implemented by serio device drivers. +pub trait Driver: Send + Sync + Sized { + /// Context data stored per connected device instance. + type Data: ForeignOwnable + Send + Sync; + + /// Device ID match table. + const ID_TABLE: &'static [DeviceId]; + + /// Called when a matching serio port is detected. + fn connect(dev: &mut Device) -> Result; + + /// Called in interrupt context when a new byte arrives from the serio port. + fn interrupt( + data: &mut ::BorrowedMut<'_>, + byte: u8, + flags: u32, + ) -> IrqReturn; + + /// Called when the device is disconnected. + fn disconnect(_data: Self::Data) {} +} + +/// Driver adapter that bridges the safe Rust [`Driver`] trait to the C serio bus subsystem. +pub struct Registration { + drv: Pin>, + _p: PhantomData, +} + +impl Registration { + /// Registers a serio driver with the kernel. + pub fn new(name: &'static crate::str::CStr) -> Result { + let drv = bindings::serio_driver { + description: name.as_char_ptr().cast(), + id_table: T::ID_TABLE.as_ptr().cast::(), + 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().cast(), + ..Default::default() + }, + }; + + let mut drv_box = Pin::new(KBox::new(drv, GFP_KERNEL)?); + + // SAFETY: `drv_box` is pinned on the kernel heap at a permanent address. + let ret = unsafe { bindings::serio_register_driver(drv_box.as_mut().get_mut()) }; + 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, + ) -> core::ffi::c_int { + let Some(serio_nn) = NonNull::new(serio) else { + return -(crate::error::code::EINVAL.to_errno()); + }; + + let mut dev = Device { ptr: serio_nn }; + + let data = match T::connect(&mut dev) { + Ok(d) => d, + Err(e) => return e.to_errno(), + }; + + let raw_data = data.into_foreign(); + // SAFETY: `serio` is valid; store driver data pointer. + unsafe { + bindings::serio_set_drvdata(serio, raw_data.cast()); + } + + // SAFETY: Open serio port to start receiving characters. + let ret = unsafe { bindings::serio_open(serio, drv) }; + if ret != 0 { + // SAFETY: Clean up driver data if open failed. + unsafe { + bindings::serio_set_drvdata(serio, core::ptr::null_mut()); + let data = ::from_foreign(raw_data); + T::disconnect(data); + } + return ret; + } + + 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: core::ffi::c_uchar, + flags: core::ffi::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 { ::borrow_mut(raw) }; + let ret = T::interrupt(&mut borrowed, data, flags); + ret.to_c() + } + + /// # 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 = ::from_foreign(raw); + T::disconnect(data); + } + } +} + +impl Drop for Registration { + fn drop(&mut self) { + // SAFETY: Unregister driver with kernel. + unsafe { + bindings::serio_unregister_driver(self.drv.as_mut().get_mut()); + } + } +} + +// SAFETY: `Registration` can be safely sent to another thread. +unsafe impl Send for Registration {} +// SAFETY: `Registration` can be safely shared across threads. +unsafe impl Sync for Registration {} -- 2.56.0