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Wysocki" , Miguel Ojeda , Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl Cc: Viresh Kumar , linux-pm@vger.kernel.org, Vincent Guittot , Stephen Boyd , Nishanth Menon , rust-for-linux@vger.kernel.org, Manos Pitsidianakis , Erik Schilling , =?utf-8?q?Alex_Benn=C3=A9e?= , Joakim Bech , Rob Herring , linux-kernel@vger.kernel.org Subject: [RFC PATCH V2 1/8] rust: Add initial bindings for OPP framework Date: Fri, 7 Jun 2024 14:42:16 +0530 Message-Id: X-Mailer: git-send-email 2.31.1.272.g89b43f80a514 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This commit adds initial Rust bindings for the Operating performance points (OPP) core. This adds bindings for `struct dev_pm_opp` and `struct dev_pm_opp_data` to begin with. Signed-off-by: Viresh Kumar --- rust/bindings/bindings_helper.h | 1 + rust/kernel/lib.rs | 2 + rust/kernel/opp.rs | 156 ++++++++++++++++++++++++++++++++ 3 files changed, 159 insertions(+) create mode 100644 rust/kernel/opp.rs diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index 39853214806d..0465b03828b8 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index c5b21251ccba..82b527c76017 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -42,6 +42,8 @@ #[cfg(CONFIG_NET)] pub mod net; pub mod of; +#[cfg(CONFIG_PM_OPP)] +pub mod opp; pub mod platform; pub mod prelude; pub mod print; diff --git a/rust/kernel/opp.rs b/rust/kernel/opp.rs new file mode 100644 index 000000000000..9e5cf0412ed5 --- /dev/null +++ b/rust/kernel/opp.rs @@ -0,0 +1,156 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Operating performance points. +//! +//! This module provides bindings for interacting with the OPP subsystem. +//! +//! C header: [`include/linux/pm_opp.h`](../../../../../../include/linux/pm_opp.h) + +use crate::{ + bindings, + device::Device, + error::{code::*, to_result, Result}, + types::{ARef, AlwaysRefCounted, Opaque}, +}; + +use core::ptr; + +/// Equivalent to `struct dev_pm_opp_data` in the C Code. +#[repr(transparent)] +pub struct Data(bindings::dev_pm_opp_data); + +impl Data { + /// Creates new instance of [`Data`]. + pub fn new(freq: u64, u_volt: u64, level: u32, turbo: bool) -> Self { + Self(bindings::dev_pm_opp_data { + turbo, + freq, + u_volt, + level, + }) + } +} + +/// Operating performance point (OPP). +/// +/// # Invariants +/// +/// The pointer stored in `Self` is non-null and valid for the lifetime of the ARef instance. In +/// particular, the ARef instance owns an increment on underlying object’s reference count. +#[repr(transparent)] +pub struct OPP(Opaque); + +// SAFETY: `OPP` only holds a pointer to a C OPP, which is safe to be used from any thread. +unsafe impl Send for OPP {} + +// SAFETY: `OPP` only holds a pointer to a C OPP, references to which are safe to be used from any +// thread. +unsafe impl Sync for OPP {} + +// SAFETY: The type invariants guarantee that [`OPP`] is always refcounted. +unsafe impl AlwaysRefCounted for OPP { + fn inc_ref(&self) { + // SAFETY: The existence of a shared reference means that the refcount is nonzero. + unsafe { bindings::dev_pm_opp_get(self.0.get()) }; + } + + unsafe fn dec_ref(obj: ptr::NonNull) { + // SAFETY: The safety requirements guarantee that the refcount is nonzero. + unsafe { bindings::dev_pm_opp_put(obj.cast().as_ptr()) } + } +} + +impl OPP { + /// Creates a reference to a [`OPP`] from a valid pointer. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the + /// returned [`OPP`] reference. + pub unsafe fn from_ptr_owned(ptr: *mut bindings::dev_pm_opp) -> Result> { + let ptr = ptr::NonNull::new(ptr).ok_or(ENODEV)?; + + // SAFETY: The safety requirements guarantee the validity of the pointer. + // + // INVARIANT: The refcount is already incremented by the C API that returned the pointer, + // and we pass ownership of the refcount to the new `ARef`. + Ok(unsafe { ARef::from_raw(ptr.cast()) }) + } + + /// Creates a reference to a [`OPP`] from a valid pointer. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the + /// returned [`OPP`] reference. + pub unsafe fn from_ptr(ptr: *mut bindings::dev_pm_opp) -> Result> { + let opp = unsafe { Self::from_ptr_owned(ptr) }?; + + // Take an extra reference to the OPP since the caller didn't take it. + opp.inc_ref(); + + Ok(opp) + } + + fn as_mut_ptr(&self) -> *mut bindings::dev_pm_opp { + self.0.get() + } + + /// Adds an OPP dynamically. + pub fn add(dev: ARef, mut data: Data) -> Result<()> { + // SAFETY: The requirements are satisfied by the existence of `Device` and its safety + // requirements. + to_result(unsafe { bindings::dev_pm_opp_add_dynamic(dev.as_raw(), &mut data.0) }) + } + + /// Removes a dynamically added OPP. + pub fn remove(dev: ARef, freq: u64) { + // SAFETY: The requirements are satisfied by the existence of `Device` and its safety + // requirements. + unsafe { bindings::dev_pm_opp_remove(dev.as_raw(), freq) }; + } + + /// Returns the frequency of an OPP. + pub fn freq(&self, index: Option) -> u64 { + let index = index.unwrap_or(0); + + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to + // use it. + unsafe { bindings::dev_pm_opp_get_freq_indexed(self.as_mut_ptr(), index) } + } + + /// Returns the voltage of an OPP. + pub fn voltage(&self) -> u64 { + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to + // use it. + unsafe { bindings::dev_pm_opp_get_voltage(self.as_mut_ptr()) } + } + + /// Returns the level of an OPP. + pub fn level(&self) -> u32 { + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to + // use it. + unsafe { bindings::dev_pm_opp_get_level(self.as_mut_ptr()) } + } + + /// Returns the power of an OPP. + pub fn power(&self) -> u64 { + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to + // use it. + unsafe { bindings::dev_pm_opp_get_power(self.as_mut_ptr()) } + } + + /// Returns the required pstate of an OPP. + pub fn required_pstate(&self, index: u32) -> u32 { + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to + // use it. + unsafe { bindings::dev_pm_opp_get_required_pstate(self.as_mut_ptr(), index) } + } + + /// Returns true if the OPP is turbo. + pub fn is_turbo(&self) -> bool { + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to + // use it. + unsafe { bindings::dev_pm_opp_is_turbo(self.as_mut_ptr()) } + } +}