Re: [PATCH V6 00/15] Rust bindings for cpufreq and OPP core + sample driver

[Danilo Krummrich <dakr@kernel.org>]

Hi Viresh,

On Tue, Jan 07, 2025 at 04:51:33PM +0530, Viresh Kumar wrote:
> Miguel / Danilo,
> 
> I would like to get some of this (if not all) merged now into the rust/dev

You mean rust-dev or staging/dev?

> branch, since this stuff has been around for some time and many other
> dependencies are already merged new (like OF, platform, device/driver). Please
> suggest how can we move forward to get that done.

Now that the device / driver, PCI and platform code has been merged, rust-device
and rust-pci are obsolete. The only thing that's left that I keep merging into
staging/dev is the DRM abstractions from the drm-misc tree. So, maybe we may
just want to drop staging/dev?

- Danilo

> 
> -------------------------8<-------------------------
> 
> This patch series introduces initial Rust bindings for two subsystems: cpufreq
> and Operating Performance Points (OPP). The bindings cover most of the
> interfaces exposed by these subsystems.
> 
> Included in this series is a sample `cpufreq` driver, `rcpufreq-dt`, which is a
> duplicate of the existing `cpufreq-dt` driver. The `cpufreq-dt` driver is a
> generic, platform-agnostic, device-tree-based driver used on many ARM platforms.
> 
> Currently, the implementation has been tested using QEMU, verifying that
> frequency transitions, various configurations, and driver binding/unbinding
> functions as expected. However, performance measurements have not been
> conducted.
> 
> For those interested in trying these patches, along with a few dependencies,
> they can be found at:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/linux.git rust/cpufreq-dt
> 
> The series includes all the patches to make it work:
> - few new APIs to cpufreq/OPP frameworks.
> - Avoiding using BIT() macro in cpufreq core (we need to make Rust work with
>   it).
> - Renaming of the cpufreq-dt platform device (this too needs to be fixed in
>   Rust).
> - Basic Rust bindings for clk and cpumask layers.
> 
> The work is based on `staging/dev` from the Rust tree, which is derived
> from v6.13-rc3.
> 
> V5->V6:
> - Rebase over latest rust/dev branch, which changed few interfaces that the
>   patches were using.
> - Included all other patches, which weren't included until now to focus only on
>   core APIs.
> - Other minor cleanups, additions.
> 
> V4->V5:
> - Rename Registration::register() as new().
> - Provide a new API: Registration::new_foreign_owned() and use it for
>   rcpufreq_dt driver.
> - Update MAINTAINERS file.
> 
> V3->V4:
> - Fix bugs with freeing of OPP structure. Dropped the Drop routine and fixed
>   reference counting.
> - Registration object of the cpufreq core is modified a bit to remove the
>   registered field, and few other cleanups.
> - Use Devres for instead of platform data.
> - Improve SAFETY comments.
> 
> V2->V3:
> - Rebased on latest rust-device changes, which removed `Data` and so few changes
>   were required to make it work.
> - use srctree links (Alice Ryhl).
> - Various changes the OPP creation APIs, new APIs: from_raw_opp() and
>   from_raw_opp_owned() (Alice Ryhl).
> - Inline as_raw() helpers (Alice Ryhl).
> - Add new interface (`OPP::Token`) for dynamically created OPPs.
> - Add Reviewed-by tag from Manos.
> - Modified/simplified cpufreq registration structure / method a bit.
> 
> V1->V2:
> - Create and use separate bindings for OF, clk, cpumask, etc (not included in
>   this patchset but pushed to the above branch). This helped removing direct
>   calls from the driver.
> - Fix wrong usage of Pinning + Vec.
> - Use Token for OPP Config.
> - Use Opaque, transparent and Aref for few structures.
> - Broken down into smaller patches to make it easy for reviewers.
> - Based over staging/rust-device.
> 
> Thanks.
> 
> Viresh Kumar (15):
>   PM / OPP: Expose refcounting helpers for the Rust implementation
>   cpufreq: Add cpufreq_table_len()
>   cpufreq: Rust implementation doesn't parse BIT() macro
>   rust: device: Add few helpers
>   rust: Add bindings for cpumask
>   rust: Add bare minimal bindings for clk framework
>   rust: Add initial bindings for OPP framework
>   rust: Extend OPP bindings for the OPP table
>   rust: Extend OPP bindings for the configuration options
>   rust: Add initial bindings for cpufreq framework
>   rust: Extend cpufreq bindings for policy and driver ops
>   rust: Extend cpufreq bindings for driver registration
>   rust: Extend OPP bindings with CPU frequency table
>   cpufreq: Add Rust based cpufreq-dt driver
>   DO-NOT_MERGE: cpufreq: Rename cpufreq-dt platdev
> 
>  MAINTAINERS                          |    2 +
>  drivers/cpufreq/Kconfig              |   12 +
>  drivers/cpufreq/Makefile             |    1 +
>  drivers/cpufreq/cpufreq-dt-platdev.c |    2 +-
>  drivers/cpufreq/rcpufreq_dt.rs       |  232 ++++++
>  drivers/opp/core.c                   |   17 +-
>  drivers/opp/opp.h                    |    1 -
>  include/linux/cpufreq.h              |   27 +-
>  include/linux/pm_opp.h               |    6 +
>  rust/bindings/bindings_helper.h      |    5 +
>  rust/helpers/cpufreq.c               |   16 +
>  rust/helpers/cpumask.c               |   35 +
>  rust/helpers/helpers.c               |    2 +
>  rust/kernel/clk.rs                   |   48 ++
>  rust/kernel/cpufreq.rs               | 1079 ++++++++++++++++++++++++++
>  rust/kernel/cpumask.rs               |   85 ++
>  rust/kernel/device.rs                |   21 +
>  rust/kernel/lib.rs                   |    6 +
>  rust/kernel/opp.rs                   |  886 +++++++++++++++++++++
>  19 files changed, 2468 insertions(+), 15 deletions(-)
>  create mode 100644 drivers/cpufreq/rcpufreq_dt.rs
>  create mode 100644 rust/helpers/cpufreq.c
>  create mode 100644 rust/helpers/cpumask.c
>  create mode 100644 rust/kernel/clk.rs
>  create mode 100644 rust/kernel/cpufreq.rs
>  create mode 100644 rust/kernel/cpumask.rs
>  create mode 100644 rust/kernel/opp.rs
> 
> -- 
> 2.31.1.272.g89b43f80a514
>