[RFC PATCH 7/8] rust: add firmware abstractions

[FUJITA Tomonori]

Hi,
Thanks for working on the firmware API!

On Mon, 20 May 2024 19:24:19 +0200
Danilo Krummrich <dakr at redhat.com> wrote:

> 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 at redhat.com>
> ---
>  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>);

Wrapping a raw pointer is not the intended use of Qpaque type?