On Fri, Dec 06, 2024 at 03:01:18PM +0100, Alice Ryhl wrote: > On Thu, Dec 5, 2024 at 3:16 PM Danilo Krummrich <dakr@xxxxxxxxxx> wrote: > > > > Implement the basic PCI abstractions required to write a basic PCI > > driver. This includes the following data structures: > > > > The `pci::Driver` trait represents the interface to the driver and > > provides `pci::Driver::probe` for the driver to implement. > > > > The `pci::Device` abstraction represents a `struct pci_dev` and provides > > abstractions for common functions, such as `pci::Device::set_master`. > > > > In order to provide the PCI specific parts to a generic > > `driver::Registration` the `driver::RegistrationOps` trait is implemented > > by `pci::Adapter`. > > > > `pci::DeviceId` implements PCI device IDs based on the generic > > `device_id::RawDevceId` abstraction. > > > > Co-developed-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxx> > > Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxx> > > Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx> > > > +/// The PCI device representation. > > +/// > > +/// A PCI device is based on an always reference counted `device:Device` instance. Cloning a PCI > > +/// device, hence, also increments the base device' reference count. > > +#[derive(Clone)] > > +pub struct Device(ARef<device::Device>); > > It seems more natural for this to be a wrapper around > `Opaque<bindings::pci_dev>`. Then you can have both &Device and > ARef<Device> depending on whether you want to hold a refcount or not. Yeah, but then every bus device has to re-implement the refcount dance we already have in `device::Device` for the underlying base `struct device`. I forgot to mention this in my previous reply to Boqun, but we even documented it this way in `device::Device` [1]. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/rust/kernel/device.rs#n28 > > Alice > > > +impl Device { > > + /// Create a PCI Device instance from an existing `device::Device`. > > + /// > > + /// # Safety > > + /// > > + /// `dev` must be an `ARef<device::Device>` whose underlying `bindings::device` is a member of > > + /// a `bindings::pci_dev`. > > + pub unsafe fn from_dev(dev: ARef<device::Device>) -> Self { > > + Self(dev) > > + } > > + > > + fn as_raw(&self) -> *mut bindings::pci_dev { > > + // SAFETY: By the type invariant `self.0.as_raw` is a pointer to the `struct device` > > + // embedded in `struct pci_dev`. > > + unsafe { container_of!(self.0.as_raw(), bindings::pci_dev, dev) as _ } > > + } > > + > > + /// Enable memory resources for this device. > > + pub fn enable_device_mem(&self) -> Result { > > + // SAFETY: `self.as_raw` is guaranteed to be a pointer to a valid `struct pci_dev`. > > + let ret = unsafe { bindings::pci_enable_device_mem(self.as_raw()) }; > > + if ret != 0 { > > + Err(Error::from_errno(ret)) > > + } else { > > + Ok(()) > > + } > > + } > > + > > + /// Enable bus-mastering for this device. > > + pub fn set_master(&self) { > > + // SAFETY: `self.as_raw` is guaranteed to be a pointer to a valid `struct pci_dev`. > > + unsafe { bindings::pci_set_master(self.as_raw()) }; > > + } > > +} > > + > > +impl AsRef<device::Device> for Device { > > + fn as_ref(&self) -> &device::Device { > > + &self.0 > > + } > > +} > > -- > > 2.47.0 > >
