Re: [PATCH v1 v1 0/4] [RUST] Framebuffer driver support

[Thomas Zimmermann <tzimmermann@suse.de>]

Hi

Am 26.01.26 um 09:17 schrieb pengfuyuan:
> This patch series adds Rust bindings and safe abstractions for the Linux
> framebuffer subsystem, enabling framebuffer drivers to be implemented in Rust.

The framebuffer subsystem is obsolete and has been deprecated for a 
decade. No new drivers accepted. Anything that really wants fbdev 
already has a driver. Can we please let it die?

Best regards
Thomas

>
> The series consists of 4 patches:
>
> 1. rust: io: mem: add ioremap_wc support
>     Adds write-combining memory mapping support to the Rust iomem abstraction,
>     which is essential for framebuffer memory regions that benefit from
>     write-combining semantics.
>
> 2. rust: device: add platdata accessors
>     Implements generic accessors for platform data, enabling drivers to access
>     platform-provided configuration. This is needed for framebuffer drivers
>     that use platform data for configuration.
>
> 3. rust: fb: add framebuffer driver support
>     Adds the core framebuffer framework abstraction, including:
>     - Device abstraction (`fb::Device`) with reference counting via `AlwaysRefCounted`
>     - Driver and Operations traits (`fb::Driver`, `fb::Operations`)
>     - Screen information wrappers (`fb::FixScreenInfo`, `fb::VarScreenInfo`)
>     - I/O operation helpers (`fb_io_read`, `fb_io_write`, `fb_io_mmap`)
>     - Blit operation helpers (`cfb_fillrect`, `cfb_copyarea`, `cfb_imageblit`)
>
> 4. rust: fb: add simplefb test driver
>     Adds a test driver that validates the framebuffer framework by porting
>     the C simplefb driver to Rust. This driver serves as both a validation
>     tool and a reference implementation for future Rust framebuffer drivers.
>
> The implementation follows the same patterns established in the DRM subsystem
> and maintains full compatibility with the existing C framebuffer subsystem.
> All C callbacks are properly bridged to Rust trait methods via the `Operations`
> trait, memory safety is ensured through proper use of `Opaque<fb_info>`, `ARef`,
> and `AlwaysRefCounted` for reference counting, type invariants are documented
> and enforced through the type system, and resource cleanup is handled via RAII
> with proper cleanup order.
>
> Testing:
> --------
> This series has been tested on:
> - ARM64 platforms with various display configurations
> - AMD RX550 graphics card
> - Moore Threads S30 graphics card
> - Multiple other graphics cards
>
> All tested configurations show normal display functionality with proper
> framebuffer initialization, rendering operations (including I/O, color register
> management, and blitting), memory mapping, and resource cleanup. The simplefb
> test driver successfully demonstrates the usage of all framebuffer framework
> APIs and validates the abstraction's correctness.
>
> The simplefb test driver serves as both a validation tool and a reference
> implementation for future Rust framebuffer drivers.
>
>
> pengfuyuan (4):
>    rust: io: mem: add ioremap_wc support
>    rust: device: add platdata accessors
>    rust: fb: add framebuffer driver support
>    rust: fb: add simplefb test driver
>
>   drivers/video/fbdev/Kconfig          |  21 +
>   drivers/video/fbdev/Makefile         |   1 +
>   drivers/video/fbdev/simplefb_rust.rs | 653 +++++++++++++++++++++++++++
>   rust/bindings/bindings_helper.h      |   2 +
>   rust/helpers/device.c                |   5 +
>   rust/helpers/io.c                    |   5 +
>   rust/kernel/device.rs                |  31 ++
>   rust/kernel/fb/blit.rs               | 106 +++++
>   rust/kernel/fb/device.rs             | 463 +++++++++++++++++++
>   rust/kernel/fb/driver.rs             | 169 +++++++
>   rust/kernel/fb/io.rs                 |  76 ++++
>   rust/kernel/fb/mod.rs                |  23 +
>   rust/kernel/fb/screeninfo.rs         | 318 +++++++++++++
>   rust/kernel/io/mem.rs                |  71 +++
>   rust/kernel/lib.rs                   |   2 +
>   15 files changed, 1946 insertions(+)
>   create mode 100644 drivers/video/fbdev/simplefb_rust.rs
>   create mode 100644 rust/kernel/fb/blit.rs
>   create mode 100644 rust/kernel/fb/device.rs
>   create mode 100644 rust/kernel/fb/driver.rs
>   create mode 100644 rust/kernel/fb/io.rs
>   create mode 100644 rust/kernel/fb/mod.rs
>   create mode 100644 rust/kernel/fb/screeninfo.rs
>

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)