diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs index 87719e58548a..fcd1b156a14a 100644 --- a/rust/kernel/io.rs +++ b/rust/kernel/io.rs @@ -225,7 +225,6 @@ macro_rules! define_read { } }; } -#[expect(unused)] pub(crate) use define_read; macro_rules! define_write { @@ -258,7 +257,6 @@ macro_rules! define_write { } }; } -#[expect(unused)] pub(crate) use define_write; /// Checks whether an access of type `U` at the given `offset` diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs index 82e128431f08..1d1a253e5d5d 100644 --- a/rust/kernel/pci.rs +++ b/rust/kernel/pci.rs @@ -40,7 +40,13 @@ pub use self::id::{ ClassMask, Vendor, // }; -pub use self::io::Bar; +pub use self::io::{ + Bar, + ConfigSpaceKind, + ConfigSpaceSize, + Extended, + Normal, // +}; pub use self::irq::{ IrqType, IrqTypes, diff --git a/rust/kernel/pci/io.rs b/rust/kernel/pci/io.rs index e3377397666e..026e7a3b69bd 100644 --- a/rust/kernel/pci/io.rs +++ b/rust/kernel/pci/io.rs @@ -8,13 +8,174 @@ use crate::{ device, devres::Devres, io::{ + define_read, + define_write, + Io, + IoCapable, + IoKnownSize, Mmio, MmioRaw, // }, prelude::*, sync::aref::ARef, // }; -use core::ops::Deref; +use core::{ + marker::PhantomData, + ops::Deref, // +}; + +/// Represents the size of a PCI configuration space. +/// +/// PCI devices can have either a *normal* (legacy) configuration space of 256 bytes, +/// or an *extended* configuration space of 4096 bytes as defined in the PCI Express +/// specification. +#[repr(usize)] +#[derive(Eq, PartialEq)] +pub enum ConfigSpaceSize { + /// 256-byte legacy PCI configuration space. + Normal = 256, + + /// 4096-byte PCIe extended configuration space. + Extended = 4096, +} + +impl ConfigSpaceSize { + /// Get the raw value of this enum. + #[inline(always)] + pub const fn into_raw(self) -> usize { + // CAST: PCI configuration space size is at most 4096 bytes, so the value always fits + // within `usize` without truncation or sign change. + self as usize + } +} + +/// Marker type for normal (256-byte) PCI configuration space. +pub struct Normal; + +/// Marker type for extended (4096-byte) PCIe configuration space. +pub struct Extended; + +/// Trait for PCI configuration space size markers. +/// +/// This trait is implemented by [`Normal`] and [`Extended`] to provide +/// compile-time knowledge of the configuration space size. +pub trait ConfigSpaceKind { + /// The size of this configuration space in bytes. + const SIZE: usize; +} + +impl ConfigSpaceKind for Normal { + const SIZE: usize = 256; +} + +impl ConfigSpaceKind for Extended { + const SIZE: usize = 4096; +} + +/// The PCI configuration space of a device. +/// +/// Provides typed read and write accessors for configuration registers +/// using the standard `pci_read_config_*` and `pci_write_config_*` helpers. +/// +/// The generic parameter `S` indicates the maximum size of the configuration space. +/// Use [`Normal`] for 256-byte legacy configuration space or [`Extended`] for +/// 4096-byte PCIe extended configuration space (default). +pub struct ConfigSpace<'a, S: ConfigSpaceKind = Extended> { + pub(crate) pdev: &'a Device, + _marker: PhantomData, +} + +/// Internal helper macros used to invoke C PCI configuration space read functions. +/// +/// This macro is intended to be used by higher-level PCI configuration space access macros +/// (define_read) and provides a unified expansion for infallible vs. fallible read semantics. It +/// emits a direct call into the corresponding C helper and performs the required cast to the Rust +/// return type. +/// +/// # Parameters +/// +/// * `$c_fn` – The C function performing the PCI configuration space write. +/// * `$self` – The I/O backend object. +/// * `$ty` – The type of the value to read. +/// * `$addr` – The PCI configuration space offset to read. +/// +/// This macro does not perform any validation; all invariants must be upheld by the higher-level +/// abstraction invoking it. +macro_rules! call_config_read { + (infallible, $c_fn:ident, $self:ident, $ty:ty, $addr:expr) => {{ + let mut val: $ty = 0; + // SAFETY: By the type invariant `$self.pdev` is a valid address. + // CAST: The offset is cast to `i32` because the C functions expect a 32-bit signed offset + // parameter. PCI configuration space size is at most 4096 bytes, so the value always fits + // within `i32` without truncation or sign change. + // Return value from C function is ignored in infallible accessors. + let _ret = unsafe { bindings::$c_fn($self.pdev.as_raw(), $addr as i32, &mut val) }; + val + }}; +} + +/// Internal helper macros used to invoke C PCI configuration space write functions. +/// +/// This macro is intended to be used by higher-level PCI configuration space access macros +/// (define_write) and provides a unified expansion for infallible vs. fallible read semantics. It +/// emits a direct call into the corresponding C helper and performs the required cast to the Rust +/// return type. +/// +/// # Parameters +/// +/// * `$c_fn` – The C function performing the PCI configuration space write. +/// * `$self` – The I/O backend object. +/// * `$ty` – The type of the written value. +/// * `$addr` – The configuration space offset to write. +/// * `$value` – The value to write. +/// +/// This macro does not perform any validation; all invariants must be upheld by the higher-level +/// abstraction invoking it. +macro_rules! call_config_write { + (infallible, $c_fn:ident, $self:ident, $ty:ty, $addr:expr, $value:expr) => { + // SAFETY: By the type invariant `$self.pdev` is a valid address. + // CAST: The offset is cast to `i32` because the C functions expect a 32-bit signed offset + // parameter. PCI configuration space size is at most 4096 bytes, so the value always fits + // within `i32` without truncation or sign change. + // Return value from C function is ignored in infallible accessors. + let _ret = unsafe { bindings::$c_fn($self.pdev.as_raw(), $addr as i32, $value) }; + }; +} + +// PCI configuration space supports 8, 16, and 32-bit accesses. +impl<'a, S: ConfigSpaceKind> IoCapable for ConfigSpace<'a, S> {} +impl<'a, S: ConfigSpaceKind> IoCapable for ConfigSpace<'a, S> {} +impl<'a, S: ConfigSpaceKind> IoCapable for ConfigSpace<'a, S> {} + +impl<'a, S: ConfigSpaceKind> Io for ConfigSpace<'a, S> { + const MIN_SIZE: usize = S::SIZE; + + /// Returns the base address of the I/O region. It is always 0 for configuration space. + #[inline] + fn addr(&self) -> usize { + 0 + } + + /// Returns the maximum size of the configuration space. + #[inline] + fn maxsize(&self) -> usize { + self.pdev.cfg_size().into_raw() + } + + // PCI configuration space does not support fallible operations. + // The default implementations from the Io trait are not used. + + define_read!(infallible, read8, call_config_read(pci_read_config_byte) -> u8); + define_read!(infallible, read16, call_config_read(pci_read_config_word) -> u16); + define_read!(infallible, read32, call_config_read(pci_read_config_dword) -> u32); + + define_write!(infallible, write8, call_config_write(pci_write_config_byte) <- u8); + define_write!(infallible, write16, call_config_write(pci_write_config_word) <- u16); + define_write!(infallible, write32, call_config_write(pci_write_config_dword) <- u32); +} + +/// Marker trait indicating ConfigSpace has a known size at compile time. +impl<'a, S: ConfigSpaceKind> IoKnownSize for ConfigSpace<'a, S> {} /// A PCI BAR to perform I/O-Operations on. /// @@ -144,4 +305,39 @@ impl Device { ) -> impl PinInit, Error> + 'a { self.iomap_region_sized::<0>(bar, name) } + + /// Returns the size of configuration space. + pub fn cfg_size(&self) -> ConfigSpaceSize { + // SAFETY: `self.as_raw` is a valid pointer to a `struct pci_dev`. + let size = unsafe { (*self.as_raw()).cfg_size }; + match size { + 256 => ConfigSpaceSize::Normal, + 4096 => ConfigSpaceSize::Extended, + _ => { + // PANIC: The PCI subsystem only ever reports the configuration space size as either + // `ConfigSpaceSize::Normal` or `ConfigSpaceSize::Extended`. + unreachable!(); + } + } + } + + /// Return an initialized normal (256-byte) config space object. + pub fn config_space<'a>(&'a self) -> ConfigSpace<'a, Normal> { + ConfigSpace { + pdev: self, + _marker: PhantomData, + } + } + + /// Return an initialized extended (4096-byte) config space object. + pub fn config_space_extended<'a>(&'a self) -> Result> { + if self.cfg_size() != ConfigSpaceSize::Extended { + return Err(EINVAL); + } + + Ok(ConfigSpace { + pdev: self, + _marker: PhantomData, + }) + } }