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0242623384
The driver model defines the lifetime of the private data stored in (and owned by) a bus device to be valid from when the driver is bound to a device (i.e. from successful probe()) until the driver is unbound from the device. This is already taken care of by the Rust implementation of the driver model. However, we still ask drivers to return a Result<Pin<KBox<Self>>> from probe(). Unlike in C, where we do not have the concept of initializers, but rather deal with uninitialized memory, drivers can just return an impl PinInit<Self, Error> instead. This contributes to more clarity to the fact that a driver returns it's device private data in probe() and the Rust driver model owns the data, manages the lifetime and - considering the lifetime - provides (safe) accessors for the driver. Hence, let probe() functions return an impl PinInit<Self, Error> instead of Result<Pin<KBox<Self>>>. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Danilo Krummrich <dakr@kernel.org>
120 lines
3.1 KiB
Rust
120 lines
3.1 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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//! Rust PCI driver sample (based on QEMU's `pci-testdev`).
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//!
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//! To make this driver probe, QEMU must be run with `-device pci-testdev`.
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use kernel::{c_str, device::Core, devres::Devres, pci, prelude::*, sync::aref::ARef};
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struct Regs;
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impl Regs {
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const TEST: usize = 0x0;
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const OFFSET: usize = 0x4;
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const DATA: usize = 0x8;
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const COUNT: usize = 0xC;
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const END: usize = 0x10;
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}
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type Bar0 = pci::Bar<{ Regs::END }>;
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#[derive(Copy, Clone, Debug)]
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struct TestIndex(u8);
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impl TestIndex {
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const NO_EVENTFD: Self = Self(0);
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}
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#[pin_data(PinnedDrop)]
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struct SampleDriver {
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pdev: ARef<pci::Device>,
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#[pin]
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bar: Devres<Bar0>,
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index: TestIndex,
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}
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kernel::pci_device_table!(
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PCI_TABLE,
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MODULE_PCI_TABLE,
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<SampleDriver as pci::Driver>::IdInfo,
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[(
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pci::DeviceId::from_id(pci::Vendor::REDHAT, 0x5),
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TestIndex::NO_EVENTFD
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)]
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);
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impl SampleDriver {
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fn testdev(index: &TestIndex, bar: &Bar0) -> Result<u32> {
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// Select the test.
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bar.write8(index.0, Regs::TEST);
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let offset = u32::from_le(bar.read32(Regs::OFFSET)) as usize;
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let data = bar.read8(Regs::DATA);
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// Write `data` to `offset` to increase `count` by one.
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//
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// Note that we need `try_write8`, since `offset` can't be checked at compile-time.
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bar.try_write8(data, offset)?;
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Ok(bar.read32(Regs::COUNT))
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}
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}
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impl pci::Driver for SampleDriver {
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type IdInfo = TestIndex;
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const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE;
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fn probe(pdev: &pci::Device<Core>, info: &Self::IdInfo) -> impl PinInit<Self, Error> {
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pin_init::pin_init_scope(move || {
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let vendor = pdev.vendor_id();
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dev_dbg!(
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pdev.as_ref(),
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"Probe Rust PCI driver sample (PCI ID: {}, 0x{:x}).\n",
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vendor,
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pdev.device_id()
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);
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pdev.enable_device_mem()?;
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pdev.set_master();
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Ok(try_pin_init!(Self {
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bar <- pdev.iomap_region_sized::<{ Regs::END }>(0, c_str!("rust_driver_pci")),
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index: *info,
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_: {
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let bar = bar.access(pdev.as_ref())?;
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dev_info!(
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pdev.as_ref(),
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"pci-testdev data-match count: {}\n",
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Self::testdev(info, bar)?
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);
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},
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pdev: pdev.into(),
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}))
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})
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}
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fn unbind(pdev: &pci::Device<Core>, this: Pin<&Self>) {
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if let Ok(bar) = this.bar.access(pdev.as_ref()) {
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// Reset pci-testdev by writing a new test index.
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bar.write8(this.index.0, Regs::TEST);
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}
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}
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}
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#[pinned_drop]
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impl PinnedDrop for SampleDriver {
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fn drop(self: Pin<&mut Self>) {
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dev_dbg!(self.pdev.as_ref(), "Remove Rust PCI driver sample.\n");
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}
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}
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kernel::module_pci_driver! {
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type: SampleDriver,
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name: "rust_driver_pci",
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authors: ["Danilo Krummrich"],
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description: "Rust PCI driver",
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license: "GPL v2",
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}
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