[V4,0/8] Rust bindings for cpufreq and OPP core + sample driver

Message

Viresh Kumar July 11, 2024, 6:57 a.m. UTC

Hello,

This adds initial rust bindings for two subsystems, cpufreq and operating
performance points (OPP). The bindings are provided for most of the interface
these subsystems expose.

This series also provides a sample cpufreq driver rcpufreq-dt, which is a
duplicate of the merged cpufreq-dt driver (A generic platform agnostic device
tree based cpufreq driver) used on most of the ARM platforms.

This is tested with the help of QEMU for now and frequency transitions, various
configurations, driver binding/unbinding work as expected. No performance
measurement is done with this.

These patches (along with few other dependencies) are pushed here for anyone to
give them a try:

git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/linux.git rust/cpufreq-dt


This depends on basic bindings for few other modules: device/driver, platform
driver, OF, clk, and cpumask. I am not looking to upstream support for them yet.

Based on staging/rust-device from the Rust tree (which is based over v6.10-rc1).

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 (8):
  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

 drivers/cpufreq/Kconfig         |   12 +
 drivers/cpufreq/Makefile        |    1 +
 drivers/cpufreq/rcpufreq_dt.rs  |  222 +++++++
 rust/bindings/bindings_helper.h |    2 +
 rust/helpers.c                  |   15 +
 rust/kernel/cpufreq.rs          | 1023 +++++++++++++++++++++++++++++++
 rust/kernel/lib.rs              |    4 +
 rust/kernel/opp.rs              |  925 ++++++++++++++++++++++++++++
 8 files changed, 2204 insertions(+)
 create mode 100644 drivers/cpufreq/rcpufreq_dt.rs
 create mode 100644 rust/kernel/cpufreq.rs
 create mode 100644 rust/kernel/opp.rs