Add an abstraction around the kernels firmware API to request firmware
images. The abstraction provides functions to access the firmware
buffer and / or copy it to a new buffer allocated with a given allocator
backend.
The firmware is released once the abstraction is dropped.
Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx>
---
rust/bindings/bindings_helper.h | 1 +
rust/kernel/firmware.rs | 74 +++++++++++++++++++++++++++++++++
rust/kernel/lib.rs | 1 +
3 files changed, 76 insertions(+)
create mode 100644 rust/kernel/firmware.rs
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index b245db8d5a87..e4ffc47da5ec 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -14,6 +14,7 @@
#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/pci.h>
diff --git a/rust/kernel/firmware.rs b/rust/kernel/firmware.rs
new file mode 100644
index 000000000000..700504fb3c9c
--- /dev/null
+++ b/rust/kernel/firmware.rs
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Firmware abstraction
+//!
+//! C header: [`include/linux/firmware.h`](../../../../include/linux/firmware.h")
+
+use crate::{bindings, device::Device, error::Error, error::Result, str::CStr, types::Opaque};
+
+/// Abstraction around a C firmware struct.
+///
+/// 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]`. Alternatively, the firmware can be copied to a new buffer using `Firmware::copy`. The
+/// firmware is released once [`Firmware`] is dropped.
+///
+/// # Examples
+///
+/// ```
+/// let fw = Firmware::request("path/to/firmware.bin", dev.as_ref())?;
+/// driver_load_firmware(fw.data());
+/// ```
+pub struct Firmware(Opaque<*const bindings::firmware>);
+
+impl Firmware {
+ /// Send a firmware request and wait for it. See also `bindings::request_firmware`.
+ pub fn request(name: &CStr, dev: &Device) -> Result<Self> {
+ let fw = Opaque::uninit();
+
+ let ret = unsafe { bindings::request_firmware(fw.get(), name.as_char_ptr(), dev.as_raw()) };
+ if ret != 0 {
+ return Err(Error::from_errno(ret));
+ }
+
+ Ok(Firmware(fw))
+ }
+
+ /// Send a request for an optional fw module. See also `bindings::request_firmware_nowarn`.
+ pub fn request_nowarn(name: &CStr, dev: &Device) -> Result<Self> {
+ let fw = Opaque::uninit();
+
+ let ret = unsafe {
+ bindings::firmware_request_nowarn(fw.get(), name.as_char_ptr(), dev.as_raw())
+ };
+ if ret != 0 {
+ return Err(Error::from_errno(ret));
+ }
+
+ Ok(Firmware(fw))
+ }
+
+ /// Returns the size of the requested firmware in bytes.
+ pub fn size(&self) -> usize {
+ unsafe { (*(*self.0.get())).size }
+ }
+
+ /// Returns the requested firmware as `&[u8]`.
+ pub fn data(&self) -> &[u8] {
+ unsafe { core::slice::from_raw_parts((*(*self.0.get())).data, self.size()) }
+ }
+}
+
+impl Drop for Firmware {
+ fn drop(&mut self) {
+ unsafe { bindings::release_firmware(*self.0.get()) };
+ }
+}
+
+// SAFETY: `Firmware` only holds a pointer to a C firmware struct, which is safe to be used from any
+// thread.
+unsafe impl Send for Firmware {}
+
+// SAFETY: `Firmware` only holds a pointer to a C firmware struct, 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 6415968ee3b8..ed97d131661a 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -35,6 +35,7 @@
#[cfg(CONFIG_DRM = "y")]
pub mod drm;
pub mod error;
+pub mod firmware;
pub mod init;
pub mod ioctl;
#[cfg(CONFIG_KUNIT)]
--
2.45.1
