Commit fdb1ac6c authored by Lee Jones's avatar Lee Jones Committed by Greg Kroah-Hartman
Browse files

samples: rust: Provide example using the new Rust MiscDevice abstraction 



This sample driver demonstrates the following basic operations:

* Register a Misc Device
* Create /dev/rust-misc-device
* Provide open call-back for the aforementioned character device
* Operate on the character device via a simple ioctl()
* Provide close call-back for the character device

Signed-off-by: default avatarLee Jones <lee@kernel.org>
Reviewed-by: default avatarDanilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241213134715.601415-3-lee@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4a9ce188

samples/rust/Kconfig

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@@ -20,6 +20,16 @@ config SAMPLE_RUST_MINIMAL 


	  If unsure, say N.



config SAMPLE_RUST_MISC_DEVICE

	tristate "Misc device"

	help

	  This option builds the Rust misc device.



	  To compile this as a module, choose M here:

	  the module will be called rust_misc_device.



	  If unsure, say N.



config SAMPLE_RUST_PRINT

	tristate "Printing macros"

	help

samples/rust/Makefile

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@@ -2,6 +2,7 @@ 
ccflags-y += -I$(src)				# needed for trace events



obj-$(CONFIG_SAMPLE_RUST_MINIMAL)		+= rust_minimal.o

obj-$(CONFIG_SAMPLE_RUST_MISC_DEVICE)		+= rust_misc_device.o

obj-$(CONFIG_SAMPLE_RUST_PRINT)			+= rust_print.o



rust_print-y := rust_print_main.o rust_print_events.o

samples/rust/rust_misc_device.rs

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// SPDX-License-Identifier: GPL-2.0



// Copyright (C) 2024 Google LLC.



//! Rust misc device sample.



use kernel::{

    c_str,

    device::Device,

    fs::File,

    ioctl::_IO,

    miscdevice::{MiscDevice, MiscDeviceOptions, MiscDeviceRegistration},

    prelude::*,

    types::ARef,

};



const RUST_MISC_DEV_HELLO: u32 = _IO('|' as u32, 0x80);



module! {

    type: RustMiscDeviceModule,

    name: "rust_misc_device",

    author: "Lee Jones",

    description: "Rust misc device sample",

    license: "GPL",

}



#[pin_data]

struct RustMiscDeviceModule {

    #[pin]

    _miscdev: MiscDeviceRegistration<RustMiscDevice>,

}



impl kernel::InPlaceModule for RustMiscDeviceModule {

    fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {

        pr_info!("Initialising Rust Misc Device Sample\n");



        let options = MiscDeviceOptions {

            name: c_str!("rust-misc-device"),

        };



        try_pin_init!(Self {

            _miscdev <- MiscDeviceRegistration::register(options),

        })

    }

}



struct RustMiscDevice {

    dev: ARef<Device>,

}



#[vtable]

impl MiscDevice for RustMiscDevice {

    type Ptr = KBox<Self>;



    fn open(_file: &File, misc: &MiscDeviceRegistration<Self>) -> Result<KBox<Self>> {

        let dev = ARef::from(misc.device());



        dev_info!(dev, "Opening Rust Misc Device Sample\n");



        Ok(KBox::new(RustMiscDevice { dev }, GFP_KERNEL)?)

    }



    fn ioctl(

        me: <Self::Ptr as kernel::types::ForeignOwnable>::Borrowed<'_>,

        _file: &File,

        cmd: u32,

        _arg: usize,

    ) -> Result<isize> {

        dev_info!(me.dev, "IOCTLing Rust Misc Device Sample\n");



        match cmd {

            RUST_MISC_DEV_HELLO => dev_info!(me.dev, "Hello from the Rust Misc Device\n"),

            _ => {

                dev_err!(me.dev, "-> IOCTL not recognised: {}\n", cmd);

                return Err(ENOTTY);

            }

        }



        Ok(0)

    }

}



impl Drop for RustMiscDevice {

    fn drop(&mut self) {

        dev_info!(self.dev, "Exiting the Rust Misc Device Sample\n");

    }

}