The Rust sample drivers currently exercise PCI facilities in isolation: rust_driver_pci covers MMIO and rust_dma covers DMA, but there is no single in-tree example that combines memory-mapped I/O, interrupts and DMA in one driver.
This series adds one. It targets QEMU's `edu` device -- a small, well-documented educational PCI device that supports exactly these three facilities and ships with any recent QEMU (`-device edu`), so the sample runs without special hardware. The sample maps BAR0, reads the PCI configuration space, and runs a set of MMIO self-tests (identification, liveness, factorial), allocates an MSI vector and registers an IRQ handler, and performs a DMA round-trip -- each stage waiting on a Completion that the IRQ handler signals. As requested by Danilo in the v2 review, the sample replaces rust_driver_pci, which it covers a superset of; the removal is the first patch. Prerequisites, that had to be implemented: - pci: rework the device enabling API: replace enable_device_mem() with enable_device(), which returns a DeviceEnableGuard that disables the device again on drop, so the enable count stays balanced across unbind/rebind. This follows the design Danilo proposed in the review of the standalone patch [1], which this series absorbs. - pci: make Vendor::from_raw() public, so a driver can match a device whose vendor ID has no symbolic name in pci_ids.h (QEMU's 0x1234), matching what C drivers already do. - completion: add complete(), so a single Completion can be reused to wait for consecutive events (e.g. back-to-back DMA transfers). The series is based on rust/rust-next and additionally depends on Danilo's "rust: irq: make Registration compatible with lifetime-bound drivers" [2], currently in linux-next. Note: DeviceEnableGuard drops from a bound scope, so pci_disable_device() can race the pci_dev bitfield word as discussed in [1]; that race predates this series and is triggerable from sysfs today. The bitops conversion is under way separately on linux-pci [3]. Tested with QEMU `-device edu`; [1] https://lore.kernel.org/rust-for-linux/[email protected] [2] https://lore.kernel.org/r/[email protected] [3] https://lore.kernel.org/linux-pci/[email protected]/ Signed-off-by: Maurice Hieronymus <[email protected]> --- Changes in v3: - Absorb the device enabling rework [1] into this series, redesigned around DeviceEnableGuard as proposed by Danilo; convert nova-core. - Remove rust_driver_pci, replaced by this sample (Danilo). - Add access to PCI configuration space (Danilo). - Rebase on rust/rust-next on top of Danilo's irq Registration rework [2]; register the handler via pci::Device::request_irq(). - Use vertical import style. - Link to v2: https://lore.kernel.org/r/[email protected] Changes in v2: - pci: Vendor::from_raw(): collected Reviewed-by from Gary Guo; wrapped code identifiers in the commit message in backticks (Gary). - pci: enable_device(): collected Reviewed-by from Fiona Behrens; made enable_device_mem() #[inline] and added a cross-reference to enable_device() in its docs (Fiona). - completion: complete(): tightened the doc comment per Gary's review (emphasise "single", drop the internal-counter detail, drop the complete_all comparison). - samples/edu: take &EduDriverData instead of &Arc<EduDriverData> in init()/test_irq()/test_dma() (Ewan Chorynski). - samples/edu: simplify wait_until_compute_has_finished() to forward read_poll_timeout()'s error via inspect_err() instead of returning a hard-coded ETIMEDOUT (Ewan Chorynski / Miguel Ojeda). - samples/edu: Rebased on rust/rust-next and adapt to the updated pci::Bar / device::Core lifetimes and pci::Driver::Data<'bound>, and obtain the BAR via into_devres(). - Link to v1: https://lore.kernel.org/r/[email protected] --- Maurice Hieronymus (5): samples: rust: remove the rust_driver_pci sample rust: pci: rework device enabling API rust: pci: make Vendor::from_raw() public rust: completion: add complete() rust: samples: add EDU PCI driver sample MAINTAINERS | 2 +- drivers/gpu/nova-core/driver.rs | 5 +- rust/kernel/pci.rs | 31 ++- rust/kernel/pci/id.rs | 2 +- rust/kernel/sync/completion.rs | 11 ++ samples/rust/Kconfig | 8 +- samples/rust/Makefile | 2 +- samples/rust/rust_driver_edu.rs | 421 ++++++++++++++++++++++++++++++++++++++++ samples/rust/rust_driver_pci.rs | 194 ------------------ 9 files changed, 471 insertions(+), 205 deletions(-) --- base-commit: 643a7c306b8ce32743d4f94dd700c8588be37e66 change-id: 20260614-b4-rust-pci-edu-driver-3e50db2dda0f prerequisite-message-id: <[email protected]> prerequisite-patch-id: 63224325d5ec73f06517bb35f8c366a086bbea19 Best regards, -- Maurice Hieronymus <[email protected]>
