diff options
| -rw-r--r-- | drivers/base/firmware_loader/Kconfig | 7 | ||||
| -rw-r--r-- | rust/bindings/bindings_helper.h | 1 | ||||
| -rw-r--r-- | rust/kernel/firmware.rs | 101 | ||||
| -rw-r--r-- | rust/kernel/lib.rs | 2 |
4 files changed, 111 insertions, 0 deletions
diff --git a/drivers/base/firmware_loader/Kconfig b/drivers/base/firmware_loader/Kconfig index 5ca00e02fe82..a03701674265 100644 --- a/drivers/base/firmware_loader/Kconfig +++ b/drivers/base/firmware_loader/Kconfig @@ -37,6 +37,13 @@ config FW_LOADER_DEBUG SHA256 checksums to the kernel log for each firmware file that is loaded. +config RUST_FW_LOADER_ABSTRACTIONS + bool "Rust Firmware Loader abstractions" + depends on RUST + depends on FW_LOADER=y + help + This enables the Rust abstractions for the firmware loader API. + if FW_LOADER config FW_LOADER_PAGED_BUF diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index ddb5644d4fd9..18a3f05115cb 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -9,6 +9,7 @@ #include <kunit/test.h> #include <linux/errname.h> #include <linux/ethtool.h> +#include <linux/firmware.h> #include <linux/jiffies.h> #include <linux/mdio.h> #include <linux/phy.h> diff --git a/rust/kernel/firmware.rs b/rust/kernel/firmware.rs new file mode 100644 index 000000000000..b55ea1b45368 --- /dev/null +++ b/rust/kernel/firmware.rs @@ -0,0 +1,101 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Firmware abstraction +//! +//! C header: [`include/linux/firmware.h`](srctree/include/linux/firmware.h") + +use crate::{bindings, device::Device, error::Error, error::Result, str::CStr}; +use core::ptr::NonNull; + +// One of the following: `bindings::request_firmware`, `bindings::firmware_request_nowarn`, +// `firmware_request_platform`, `bindings::request_firmware_direct` +type FwFunc = + unsafe extern "C" fn(*mut *const bindings::firmware, *const i8, *mut bindings::device) -> i32; + +/// Abstraction around a C `struct firmware`. +/// +/// This is a simple abstraction around the C firmware API. Just like with the C API, firmware can +/// be requested. Once requested the abstraction provides direct access to the firmware buffer as +/// `&[u8]`. The firmware is released once [`Firmware`] is dropped. +/// +/// # Invariants +/// +/// The pointer is valid, and has ownership over the instance of `struct firmware`. +/// +/// Once requested, the `Firmware` backing buffer is not modified until it is freed when `Firmware` +/// is dropped. +/// +/// # Examples +/// +/// ``` +/// # use kernel::{c_str, device::Device, firmware::Firmware}; +/// +/// # // SAFETY: *NOT* safe, just for the example to get an `ARef<Device>` instance +/// # let dev = unsafe { Device::from_raw(core::ptr::null_mut()) }; +/// +/// let fw = Firmware::request(c_str!("path/to/firmware.bin"), &dev).unwrap(); +/// let blob = fw.data(); +/// ``` +pub struct Firmware(NonNull<bindings::firmware>); + +impl Firmware { + fn request_internal(name: &CStr, dev: &Device, func: FwFunc) -> Result<Self> { + let mut fw: *mut bindings::firmware = core::ptr::null_mut(); + let pfw: *mut *mut bindings::firmware = &mut fw; + + // SAFETY: `pfw` is a valid pointer to a NULL initialized `bindings::firmware` pointer. + // `name` and `dev` are valid as by their type invariants. + let ret = unsafe { func(pfw as _, name.as_char_ptr(), dev.as_raw()) }; + if ret != 0 { + return Err(Error::from_errno(ret)); + } + + // SAFETY: `func` not bailing out with a non-zero error code, guarantees that `fw` is a + // valid pointer to `bindings::firmware`. + Ok(Firmware(unsafe { NonNull::new_unchecked(fw) })) + } + + /// Send a firmware request and wait for it. See also `bindings::request_firmware`. + pub fn request(name: &CStr, dev: &Device) -> Result<Self> { + Self::request_internal(name, dev, bindings::request_firmware) + } + + /// Send a request for an optional firmware module. See also + /// `bindings::firmware_request_nowarn`. + pub fn request_nowarn(name: &CStr, dev: &Device) -> Result<Self> { + Self::request_internal(name, dev, bindings::firmware_request_nowarn) + } + + fn as_raw(&self) -> *mut bindings::firmware { + self.0.as_ptr() + } + + /// Returns the size of the requested firmware in bytes. + pub fn size(&self) -> usize { + // SAFETY: Safe by the type invariant. + unsafe { (*self.as_raw()).size } + } + + /// Returns the requested firmware as `&[u8]`. + pub fn data(&self) -> &[u8] { + // SAFETY: Safe by the type invariant. Additionally, `bindings::firmware` guarantees, if + // successfully requested, that `bindings::firmware::data` has a size of + // `bindings::firmware::size` bytes. + unsafe { core::slice::from_raw_parts((*self.as_raw()).data, self.size()) } + } +} + +impl Drop for Firmware { + fn drop(&mut self) { + // SAFETY: Safe by the type invariant. + unsafe { bindings::release_firmware(self.as_raw()) }; + } +} + +// SAFETY: `Firmware` only holds a pointer to a C `struct firmware`, which is safe to be used from +// any thread. +unsafe impl Send for Firmware {} + +// SAFETY: `Firmware` only holds a pointer to a C `struct firmware`, references to which are safe to +// be used from any thread. +unsafe impl Sync for Firmware {} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index dd1207f1a873..7707cb013ce9 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -30,6 +30,8 @@ pub mod alloc; mod build_assert; pub mod device; pub mod error; +#[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)] +pub mod firmware; pub mod init; pub mod ioctl; #[cfg(CONFIG_KUNIT)] |