// SPDX-License-Identifier: GPL-2.0

//! Rust auxiliary driver sample (based on a PCI driver for QEMU's `pci-testdev`).
//!
//! To make this driver probe, QEMU must be run with `-device pci-testdev`.

use kernel::{
    auxiliary, bindings, c_str, device::Core, driver, error::Error, pci, prelude::*, InPlaceModule,
};

use pin_init::PinInit;

const MODULE_NAME: &CStr = <LocalModule as kernel::ModuleMetadata>::NAME;
const AUXILIARY_NAME: &CStr = c_str!("auxiliary");

struct AuxiliaryDriver;

kernel::auxiliary_device_table!(
    AUX_TABLE,
    MODULE_AUX_TABLE,
    <AuxiliaryDriver as auxiliary::Driver>::IdInfo,
    [(auxiliary::DeviceId::new(MODULE_NAME, AUXILIARY_NAME), ())]
);

impl auxiliary::Driver for AuxiliaryDriver {
    type IdInfo = ();

    const ID_TABLE: auxiliary::IdTable<Self::IdInfo> = &AUX_TABLE;

    fn probe(adev: &auxiliary::Device<Core>, _info: &Self::IdInfo) -> Result<Pin<KBox<Self>>> {
        dev_info!(
            adev.as_ref(),
            "Probing auxiliary driver for auxiliary device with id={}\n",
            adev.id()
        );

        ParentDriver::connect(adev)?;

        let this = KBox::new(Self, GFP_KERNEL)?;

        Ok(this.into())
    }
}

struct ParentDriver {
    _reg: [auxiliary::Registration; 2],
}

kernel::pci_device_table!(
    PCI_TABLE,
    MODULE_PCI_TABLE,
    <ParentDriver as pci::Driver>::IdInfo,
    [(
        pci::DeviceId::from_id(bindings::PCI_VENDOR_ID_REDHAT, 0x5),
        ()
    )]
);

impl pci::Driver for ParentDriver {
    type IdInfo = ();

    const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE;

    fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> Result<Pin<KBox<Self>>> {
        let this = KBox::new(
            Self {
                _reg: [
                    auxiliary::Registration::new(pdev.as_ref(), AUXILIARY_NAME, 0, MODULE_NAME)?,
                    auxiliary::Registration::new(pdev.as_ref(), AUXILIARY_NAME, 1, MODULE_NAME)?,
                ],
            },
            GFP_KERNEL,
        )?;

        Ok(this.into())
    }
}

impl ParentDriver {
    fn connect(adev: &auxiliary::Device) -> Result<()> {
        let parent = adev.parent().ok_or(EINVAL)?;
        let pdev: &pci::Device = parent.try_into()?;

        dev_info!(
            adev.as_ref(),
            "Connect auxiliary {} with parent: VendorID={:#x}, DeviceID={:#x}\n",
            adev.id(),
            pdev.vendor_id(),
            pdev.device_id()
        );

        Ok(())
    }
}

#[pin_data]
struct SampleModule {
    #[pin]
    _pci_driver: driver::Registration<pci::Adapter<ParentDriver>>,
    #[pin]
    _aux_driver: driver::Registration<auxiliary::Adapter<AuxiliaryDriver>>,
}

impl InPlaceModule for SampleModule {
    fn init(module: &'static kernel::ThisModule) -> impl PinInit<Self, Error> {
        try_pin_init!(Self {
            _pci_driver <- driver::Registration::new(MODULE_NAME, module),
            _aux_driver <- driver::Registration::new(MODULE_NAME, module),
        })
    }
}

module! {
    type: SampleModule,
    name: "rust_driver_auxiliary",
    authors: ["Danilo Krummrich"],
    description: "Rust auxiliary driver",
    license: "GPL v2",
}