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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 V3 5/8] rust: Extend cpufreq bindings for policy and driver ops Date: Wed, 3 Jul 2024 12:44:30 +0530 Message-Id: <1edf90cbde4588c7d71cdbcdf853640cf64a71d3.1719990273.git.viresh.kumar@linaro.org> 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 extends the cpufreq bindings with bindings for cpufreq policy and driver operations. Signed-off-by: Viresh Kumar --- rust/kernel/cpufreq.rs | 315 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 313 insertions(+), 2 deletions(-) diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs index 3f3ffd9abaa2..6f9d34ebbcb0 100644 --- a/rust/kernel/cpufreq.rs +++ b/rust/kernel/cpufreq.rs @@ -7,15 +7,20 @@ //! C header: [`include/linux/cpufreq.h`](srctree/include/linux/cpufreq.h) use crate::{ - bindings, - error::{code::*, to_result, Result}, + bindings, clk, cpumask, + device::Device, + error::{code::*, from_err_ptr, to_result, Result, VTABLE_DEFAULT_ERROR}, prelude::*, + types::{ARef, ForeignOwnable}, }; use core::{ pin::Pin, + ptr::self, }; +use macros::vtable; + /// Default transition latency value. pub const ETERNAL_LATENCY: u32 = bindings::CPUFREQ_ETERNAL as u32; @@ -252,3 +257,309 @@ pub fn data(&self, index: usize) -> Result { Ok(unsafe { (*self.ptr.add(index)).driver_data }) } } + +/// Equivalent to `struct cpufreq_policy` in the C code. +pub struct Policy { + ptr: *mut bindings::cpufreq_policy, + put_cpu: bool, + cpumask: cpumask::Cpumask, +} + +impl Policy { + /// Creates a new instance of [`Policy`]. + /// + /// # Safety + /// + /// Callers must ensure that `ptr` is valid and non-null. + pub unsafe fn from_raw_policy(ptr: *mut bindings::cpufreq_policy) -> Self { + Self { + ptr, + put_cpu: false, + // SAFETY: The pointer is guaranteed to be valid for the lifetime of `Self`. The `cpus` + // pointer is guaranteed to be valid by the C code. + cpumask: unsafe { cpumask::Cpumask::from_raw((*ptr).cpus) }, + } + } + + fn from_cpu(cpu: u32) -> Result { + // SAFETY: It is safe to call `cpufreq_cpu_get()` for any CPU. + let ptr = from_err_ptr(unsafe { bindings::cpufreq_cpu_get(cpu) })?; + + // SAFETY: The pointer is guaranteed to be valid by the C code. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + policy.put_cpu = true; + Ok(policy) + } + + /// Raw pointer to the underlying cpufreq policy. + #[inline] + pub fn as_raw(&self) -> *mut bindings::cpufreq_policy { + self.ptr + } + + fn as_ref(&self) -> &bindings::cpufreq_policy { + // SAFETY: By the type invariants, we know that `self` owns a reference to the pointer. + unsafe { &(*self.ptr) } + } + fn as_mut_ref(&mut self) -> &mut bindings::cpufreq_policy { + // SAFETY: By the type invariants, we know that `self` owns a reference to the pointer. + unsafe { &mut (*self.ptr) } + } + + /// Returns the primary CPU for a cpufreq policy. + pub fn cpu(&self) -> u32 { + self.as_ref().cpu + } + + /// Returns the minimum frequency for a cpufreq policy. + pub fn min(&self) -> u32 { + self.as_ref().min + } + + /// Returns the maximum frequency for a cpufreq policy. + pub fn max(&self) -> u32 { + self.as_ref().max + } + + /// Returns the current frequency for a cpufreq policy. + pub fn cur(&self) -> u32 { + self.as_ref().cur + } + + /// Sets the suspend frequency for a cpufreq policy. + pub fn set_suspend_freq(&mut self, freq: u32) -> &mut Self { + self.as_mut_ref().suspend_freq = freq; + self + } + + /// Returns the suspend frequency for a cpufreq policy. + pub fn suspend_freq(&self) -> u32 { + self.as_ref().suspend_freq + } + + /// Provides a wrapper to the generic suspend routine. + pub fn generic_suspend(&self) -> Result<()> { + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to + // use it now. + to_result(unsafe { bindings::cpufreq_generic_suspend(self.as_raw()) }) + } + + /// Provides a wrapper to the generic get routine. + pub fn generic_get(&self) -> Result { + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to + // use it now. + Ok(unsafe { bindings::cpufreq_generic_get(self.cpu()) }) + } + + /// Provides a wrapper to the register em with OPP routine. + pub fn register_em_opp(&self) { + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to + // use it now. + unsafe { bindings::cpufreq_register_em_with_opp(self.as_raw()) }; + } + + /// Gets raw pointer to cpufreq policy's CPUs mask. + pub fn cpus(&mut self) -> &mut cpumask::Cpumask { + &mut self.cpumask + } + + /// Sets clock for a cpufreq policy. + pub fn set_clk(&mut self, dev: &Device, name: Option<&CStr>) -> Result { + let clk = clk::Clk::new(dev, name)?; + self.as_mut_ref().clk = clk.as_raw(); + Ok(clk) + } + + /// Allows frequency switching code to run on any CPU. + pub fn set_dvfs_possible_from_any_cpu(&mut self) -> &mut Self { + self.as_mut_ref().dvfs_possible_from_any_cpu = true; + self + } + + /// Sets transition latency for a cpufreq policy. + pub fn set_transition_latency(&mut self, latency: u32) -> &mut Self { + self.as_mut_ref().cpuinfo.transition_latency = latency; + self + } + + /// Returns the cpufreq table for a cpufreq policy. The cpufreq table is recreated in a + /// light-weight manner from the raw pointer. The table in C code is not freed once this table + /// is dropped. + pub fn freq_table(&self) -> Result { + if self.as_ref().freq_table.is_null() { + return Err(EINVAL); + } + + // SAFETY: The `freq_table` is guaranteed to be valid. + Ok(unsafe { Table::from_raw(self.as_ref().freq_table) }) + } + + /// Sets the cpufreq table for a cpufreq policy. + /// + /// The cpufreq driver must guarantee that the frequency table does not get freed while it is + /// still being used by the C code. + pub fn set_freq_table(&mut self, table: &Table) -> &mut Self { + self.as_mut_ref().freq_table = table.as_raw(); + self + } + + /// Returns the data for a cpufreq policy. + pub fn data(&mut self) -> Option<::Borrowed<'_>> { + if self.as_ref().driver_data.is_null() { + None + } else { + // SAFETY: The data is earlier set by us from [`set_data()`]. + Some(unsafe { T::borrow(self.as_ref().driver_data) }) + } + } + + // Sets the data for a cpufreq policy. + fn set_data(&mut self, data: T) -> Result<()> { + if self.as_ref().driver_data.is_null() { + // Pass the ownership of the data to the foreign interface. + self.as_mut_ref().driver_data = ::into_foreign(data) as _; + Ok(()) + } else { + Err(EBUSY) + } + } + + // Returns the data for a cpufreq policy. + fn clear_data(&mut self) -> Option { + if self.as_ref().driver_data.is_null() { + None + } else { + // SAFETY: The data is earlier set by us from [`set_data()`]. It is safe to take back + // the ownership of the data from the foreign interface. + let data = + Some(unsafe { ::from_foreign(self.as_ref().driver_data) }); + self.as_mut_ref().driver_data = ptr::null_mut(); + data + } + } +} + +impl Drop for Policy { + fn drop(&mut self) { + if self.put_cpu { + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to + // relinquish it now. + unsafe { bindings::cpufreq_cpu_put(self.as_raw()) }; + } + } +} + +/// Operations to be implemented by a cpufreq driver. +#[vtable] +pub trait Driver { + /// Driver specific data. + /// + /// Corresponds to the data retrieved via the kernel's + /// `cpufreq_get_driver_data()` function. + /// + /// Require that `Data` implements `ForeignOwnable`. We guarantee to + /// never move the underlying wrapped data structure. + type Data: ForeignOwnable; + + /// Policy specific data. + /// + /// Require that `PData` implements `ForeignOwnable`. We guarantee to + /// never move the underlying wrapped data structure. + type PData: ForeignOwnable; + + /// Policy's init callback. + fn init(policy: &mut Policy) -> Result; + + /// Policy's exit callback. + fn exit(_policy: &mut Policy, _data: Option) -> Result<()> { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's online callback. + fn online(_policy: &mut Policy) -> Result<()> { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's offline callback. + fn offline(_policy: &mut Policy) -> Result<()> { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's suspend callback. + fn suspend(_policy: &mut Policy) -> Result<()> { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's resume callback. + fn resume(_policy: &mut Policy) -> Result<()> { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's ready callback. + fn ready(_policy: &mut Policy) { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's verify callback. + fn verify(data: &mut PolicyData) -> Result<()>; + + /// Policy's setpolicy callback. + fn setpolicy(_policy: &mut Policy) -> Result<()> { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's target callback. + fn target(_policy: &mut Policy, _target_freq: u32, _relation: Relation) -> Result<()> { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's target_index callback. + fn target_index(_policy: &mut Policy, _index: u32) -> Result<()> { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's fast_switch callback. + fn fast_switch(_policy: &mut Policy, _target_freq: u32) -> u32 { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's adjust_perf callback. + fn adjust_perf(_policy: &mut Policy, _min_perf: u64, _target_perf: u64, _capacity: u64) { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's get_intermediate callback. + fn get_intermediate(_policy: &mut Policy, _index: u32) -> u32 { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's target_intermediate callback. + fn target_intermediate(_policy: &mut Policy, _index: u32) -> Result<()> { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's get callback. + fn get(_policy: &mut Policy) -> Result { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's update_limits callback. + fn update_limits(_policy: &mut Policy) { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's bios_limit callback. + fn bios_limit(_policy: &mut Policy, _limit: &mut u32) -> Result<()> { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's set_boost callback. + fn set_boost(_policy: &mut Policy, _state: i32) -> Result<()> { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } + + /// Policy's register_em callback. + fn register_em(_policy: &mut Policy) { + kernel::build_error(VTABLE_DEFAULT_ERROR) + } +}