Commit b0b7301b authored by Danilo Krummrich's avatar Danilo Krummrich
Browse files

samples: rust: auxiliary: illustrate driver interaction 



Illustrate how a parent driver of an auxiliary driver can take advantage
of the device context guarantees given by the auxiliary bus and
subsequently safely derive its device private data.

Reviewed-by: default avatarAlice Ryhl <aliceryhl@google.com>
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
parent 710ac546

samples/rust/rust_driver_auxiliary.rs

+19 −3
Original line number Diff line number Diff line
@@ -5,10 +5,17 @@ 
//! To make this driver probe, QEMU must be run with `-device pci-testdev`.



use kernel::{

    auxiliary, c_str, device::Core, devres::Devres, driver, error::Error, pci, prelude::*,

    auxiliary, c_str,

    device::{Bound, Core},

    devres::Devres,

    driver,

    error::Error,

    pci,

    prelude::*,

    InPlaceModule,

};



use core::any::TypeId;

use pin_init::PinInit;



const MODULE_NAME: &CStr = <LocalModule as kernel::ModuleMetadata>::NAME;
@@ -43,6 +50,7 @@ fn probe(adev: &auxiliary::Device<Core>, _info: &Self::IdInfo) -> impl PinInit<S 


#[pin_data]

struct ParentDriver {

    private: TypeId,

    #[pin]

    _reg0: Devres<auxiliary::Registration>,

    #[pin]
@@ -63,6 +71,7 @@ impl pci::Driver for ParentDriver { 


    fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> impl PinInit<Self, Error> {

        try_pin_init!(Self {

            private: TypeId::of::<Self>(),

            _reg0 <- auxiliary::Registration::new(pdev.as_ref(), AUXILIARY_NAME, 0, MODULE_NAME),

            _reg1 <- auxiliary::Registration::new(pdev.as_ref(), AUXILIARY_NAME, 1, MODULE_NAME),

        })
@@ -70,9 +79,10 @@ fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> impl PinInit<Self, E 
}



impl ParentDriver {

    fn connect(adev: &auxiliary::Device) -> Result {

    fn connect(adev: &auxiliary::Device<Bound>) -> Result {

        let dev = adev.parent();

        let pdev: &pci::Device = dev.try_into()?;

        let pdev: &pci::Device<Bound> = dev.try_into()?;

        let drvdata = dev.drvdata::<Self>()?;



        dev_info!(

            dev,
@@ -82,6 +92,12 @@ fn connect(adev: &auxiliary::Device) -> Result { 
            pdev.device_id()

        );



        dev_info!(

            dev,

            "We have access to the private data of {:?}.\n",

            drvdata.private

        );



        Ok(())

    }

}