From a7e735169db72c6c991a5f8397fb094a80ea3391 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Fri, 11 Apr 2025 13:53:37 +0530 Subject: [PATCH 01/21] rust: cpumask: Add few more helpers Add few more cpumask helpers that are required by the Rust abstraction. Signed-off-by: Viresh Kumar Acked-by: Yury Norov [NVIDIA] --- rust/helpers/cpumask.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/rust/helpers/cpumask.c b/rust/helpers/cpumask.c index 2d380a86c34a..eb10598a0242 100644 --- a/rust/helpers/cpumask.c +++ b/rust/helpers/cpumask.c @@ -7,16 +7,41 @@ void rust_helper_cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp) cpumask_set_cpu(cpu, dstp); } +void rust_helper___cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp) +{ + __cpumask_set_cpu(cpu, dstp); +} + void rust_helper_cpumask_clear_cpu(int cpu, struct cpumask *dstp) { cpumask_clear_cpu(cpu, dstp); } +void rust_helper___cpumask_clear_cpu(int cpu, struct cpumask *dstp) +{ + __cpumask_clear_cpu(cpu, dstp); +} + +bool rust_helper_cpumask_test_cpu(int cpu, struct cpumask *srcp) +{ + return cpumask_test_cpu(cpu, srcp); +} + void rust_helper_cpumask_setall(struct cpumask *dstp) { cpumask_setall(dstp); } +bool rust_helper_cpumask_empty(struct cpumask *srcp) +{ + return cpumask_empty(srcp); +} + +bool rust_helper_cpumask_full(struct cpumask *srcp) +{ + return cpumask_full(srcp); +} + unsigned int rust_helper_cpumask_weight(struct cpumask *srcp) { return cpumask_weight(srcp); From 8961b8cb3099abd06486394aaf12dd535baaf070 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 6 Jun 2024 15:23:39 +0530 Subject: [PATCH 02/21] rust: cpumask: Add initial abstractions Add initial Rust abstractions for struct cpumask, covering a subset of its APIs. Additional APIs can be added as needed. These abstractions will be used in upcoming Rust support for cpufreq and OPP frameworks. Signed-off-by: Viresh Kumar Reviewed-by: Yury Norov [NVIDIA] --- rust/kernel/cpumask.rs | 330 +++++++++++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 1 + 2 files changed, 331 insertions(+) create mode 100644 rust/kernel/cpumask.rs diff --git a/rust/kernel/cpumask.rs b/rust/kernel/cpumask.rs new file mode 100644 index 000000000000..c90bfac9346a --- /dev/null +++ b/rust/kernel/cpumask.rs @@ -0,0 +1,330 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! CPU Mask abstractions. +//! +//! C header: [`include/linux/cpumask.h`](srctree/include/linux/cpumask.h) + +use crate::{ + alloc::{AllocError, Flags}, + prelude::*, + types::Opaque, +}; + +#[cfg(CONFIG_CPUMASK_OFFSTACK)] +use core::ptr::{self, NonNull}; + +#[cfg(not(CONFIG_CPUMASK_OFFSTACK))] +use core::mem::MaybeUninit; + +use core::ops::{Deref, DerefMut}; + +/// A CPU Mask. +/// +/// Rust abstraction for the C `struct cpumask`. +/// +/// # Invariants +/// +/// A [`Cpumask`] instance always corresponds to a valid C `struct cpumask`. +/// +/// The callers must ensure that the `struct cpumask` is valid for access and +/// remains valid for the lifetime of the returned reference. +/// +/// ## Examples +/// +/// The following example demonstrates how to update a [`Cpumask`]. +/// +/// ``` +/// use kernel::bindings; +/// use kernel::cpumask::Cpumask; +/// +/// fn set_clear_cpu(ptr: *mut bindings::cpumask, set_cpu: u32, clear_cpu: i32) { +/// // SAFETY: The `ptr` is valid for writing and remains valid for the lifetime of the +/// // returned reference. +/// let mask = unsafe { Cpumask::as_mut_ref(ptr) }; +/// +/// mask.set(set_cpu); +/// mask.clear(clear_cpu); +/// } +/// ``` +#[repr(transparent)] +pub struct Cpumask(Opaque); + +impl Cpumask { + /// Creates a mutable reference to an existing `struct cpumask` pointer. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid for writing and remains valid for the lifetime + /// of the returned reference. + pub unsafe fn as_mut_ref<'a>(ptr: *mut bindings::cpumask) -> &'a mut Self { + // SAFETY: Guaranteed by the safety requirements of the function. + // + // INVARIANT: The caller ensures that `ptr` is valid for writing and remains valid for the + // lifetime of the returned reference. + unsafe { &mut *ptr.cast() } + } + + /// Creates a reference to an existing `struct cpumask` pointer. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid for reading and remains valid for the lifetime + /// of the returned reference. + pub unsafe fn as_ref<'a>(ptr: *const bindings::cpumask) -> &'a Self { + // SAFETY: Guaranteed by the safety requirements of the function. + // + // INVARIANT: The caller ensures that `ptr` is valid for reading and remains valid for the + // lifetime of the returned reference. + unsafe { &*ptr.cast() } + } + + /// Obtain the raw `struct cpumask` pointer. + pub fn as_raw(&self) -> *mut bindings::cpumask { + let this: *const Self = self; + this.cast_mut().cast() + } + + /// Set `cpu` in the cpumask. + /// + /// ATTENTION: Contrary to C, this Rust `set()` method is non-atomic. + /// This mismatches kernel naming convention and corresponds to the C + /// function `__cpumask_set_cpu()`. + #[inline] + pub fn set(&mut self, cpu: u32) { + // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `__cpumask_set_cpu`. + unsafe { bindings::__cpumask_set_cpu(cpu, self.as_raw()) }; + } + + /// Clear `cpu` in the cpumask. + /// + /// ATTENTION: Contrary to C, this Rust `clear()` method is non-atomic. + /// This mismatches kernel naming convention and corresponds to the C + /// function `__cpumask_clear_cpu()`. + #[inline] + pub fn clear(&mut self, cpu: i32) { + // SAFETY: By the type invariant, `self.as_raw` is a valid argument to + // `__cpumask_clear_cpu`. + unsafe { bindings::__cpumask_clear_cpu(cpu, self.as_raw()) }; + } + + /// Test `cpu` in the cpumask. + /// + /// Equivalent to the kernel's `cpumask_test_cpu` API. + #[inline] + pub fn test(&self, cpu: i32) -> bool { + // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `cpumask_test_cpu`. + unsafe { bindings::cpumask_test_cpu(cpu, self.as_raw()) } + } + + /// Set all CPUs in the cpumask. + /// + /// Equivalent to the kernel's `cpumask_setall` API. + #[inline] + pub fn setall(&mut self) { + // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `cpumask_setall`. + unsafe { bindings::cpumask_setall(self.as_raw()) }; + } + + /// Checks if cpumask is empty. + /// + /// Equivalent to the kernel's `cpumask_empty` API. + #[inline] + pub fn empty(&self) -> bool { + // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `cpumask_empty`. + unsafe { bindings::cpumask_empty(self.as_raw()) } + } + + /// Checks if cpumask is full. + /// + /// Equivalent to the kernel's `cpumask_full` API. + #[inline] + pub fn full(&self) -> bool { + // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `cpumask_full`. + unsafe { bindings::cpumask_full(self.as_raw()) } + } + + /// Get weight of the cpumask. + /// + /// Equivalent to the kernel's `cpumask_weight` API. + #[inline] + pub fn weight(&self) -> u32 { + // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `cpumask_weight`. + unsafe { bindings::cpumask_weight(self.as_raw()) } + } + + /// Copy cpumask. + /// + /// Equivalent to the kernel's `cpumask_copy` API. + #[inline] + pub fn copy(&self, dstp: &mut Self) { + // SAFETY: By the type invariant, `Self::as_raw` is a valid argument to `cpumask_copy`. + unsafe { bindings::cpumask_copy(dstp.as_raw(), self.as_raw()) }; + } +} + +/// A CPU Mask pointer. +/// +/// Rust abstraction for the C `struct cpumask_var_t`. +/// +/// # Invariants +/// +/// A [`CpumaskVar`] instance always corresponds to a valid C `struct cpumask_var_t`. +/// +/// The callers must ensure that the `struct cpumask_var_t` is valid for access and remains valid +/// for the lifetime of [`CpumaskVar`]. +/// +/// ## Examples +/// +/// The following example demonstrates how to create and update a [`CpumaskVar`]. +/// +/// ``` +/// use kernel::cpumask::CpumaskVar; +/// +/// let mut mask = CpumaskVar::new_zero(GFP_KERNEL).unwrap(); +/// +/// assert!(mask.empty()); +/// mask.set(2); +/// assert!(mask.test(2)); +/// mask.set(3); +/// assert!(mask.test(3)); +/// assert_eq!(mask.weight(), 2); +/// +/// let mask2 = CpumaskVar::try_clone(&mask).unwrap(); +/// assert!(mask2.test(2)); +/// assert!(mask2.test(3)); +/// assert_eq!(mask2.weight(), 2); +/// ``` +pub struct CpumaskVar { + #[cfg(CONFIG_CPUMASK_OFFSTACK)] + ptr: NonNull, + #[cfg(not(CONFIG_CPUMASK_OFFSTACK))] + mask: Cpumask, +} + +impl CpumaskVar { + /// Creates a zero-initialized instance of the [`CpumaskVar`]. + pub fn new_zero(_flags: Flags) -> Result { + Ok(Self { + #[cfg(CONFIG_CPUMASK_OFFSTACK)] + ptr: { + let mut ptr: *mut bindings::cpumask = ptr::null_mut(); + + // SAFETY: It is safe to call this method as the reference to `ptr` is valid. + // + // INVARIANT: The associated memory is freed when the `CpumaskVar` goes out of + // scope. + unsafe { bindings::zalloc_cpumask_var(&mut ptr, _flags.as_raw()) }; + NonNull::new(ptr.cast()).ok_or(AllocError)? + }, + + #[cfg(not(CONFIG_CPUMASK_OFFSTACK))] + // SAFETY: FFI type is valid to be zero-initialized. + // + // INVARIANT: The associated memory is freed when the `CpumaskVar` goes out of scope. + mask: unsafe { core::mem::zeroed() }, + }) + } + + /// Creates an instance of the [`CpumaskVar`]. + /// + /// # Safety + /// + /// The caller must ensure that the returned [`CpumaskVar`] is properly initialized before + /// getting used. + pub unsafe fn new(_flags: Flags) -> Result { + Ok(Self { + #[cfg(CONFIG_CPUMASK_OFFSTACK)] + ptr: { + let mut ptr: *mut bindings::cpumask = ptr::null_mut(); + + // SAFETY: It is safe to call this method as the reference to `ptr` is valid. + // + // INVARIANT: The associated memory is freed when the `CpumaskVar` goes out of + // scope. + unsafe { bindings::alloc_cpumask_var(&mut ptr, _flags.as_raw()) }; + NonNull::new(ptr.cast()).ok_or(AllocError)? + }, + #[cfg(not(CONFIG_CPUMASK_OFFSTACK))] + // SAFETY: Guaranteed by the safety requirements of the function. + // + // INVARIANT: The associated memory is freed when the `CpumaskVar` goes out of scope. + mask: unsafe { MaybeUninit::uninit().assume_init() }, + }) + } + + /// Creates a mutable reference to an existing `struct cpumask_var_t` pointer. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid for writing and remains valid for the lifetime + /// of the returned reference. + pub unsafe fn as_mut_ref<'a>(ptr: *mut bindings::cpumask_var_t) -> &'a mut Self { + // SAFETY: Guaranteed by the safety requirements of the function. + // + // INVARIANT: The caller ensures that `ptr` is valid for writing and remains valid for the + // lifetime of the returned reference. + unsafe { &mut *ptr.cast() } + } + + /// Creates a reference to an existing `struct cpumask_var_t` pointer. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid for reading and remains valid for the lifetime + /// of the returned reference. + pub unsafe fn as_ref<'a>(ptr: *const bindings::cpumask_var_t) -> &'a Self { + // SAFETY: Guaranteed by the safety requirements of the function. + // + // INVARIANT: The caller ensures that `ptr` is valid for reading and remains valid for the + // lifetime of the returned reference. + unsafe { &*ptr.cast() } + } + + /// Clones cpumask. + pub fn try_clone(cpumask: &Cpumask) -> Result { + // SAFETY: The returned cpumask_var is initialized right after this call. + let mut cpumask_var = unsafe { Self::new(GFP_KERNEL) }?; + + cpumask.copy(&mut cpumask_var); + Ok(cpumask_var) + } +} + +// Make [`CpumaskVar`] behave like a pointer to [`Cpumask`]. +impl Deref for CpumaskVar { + type Target = Cpumask; + + #[cfg(CONFIG_CPUMASK_OFFSTACK)] + fn deref(&self) -> &Self::Target { + // SAFETY: The caller owns CpumaskVar, so it is safe to deref the cpumask. + unsafe { &*self.ptr.as_ptr() } + } + + #[cfg(not(CONFIG_CPUMASK_OFFSTACK))] + fn deref(&self) -> &Self::Target { + &self.mask + } +} + +impl DerefMut for CpumaskVar { + #[cfg(CONFIG_CPUMASK_OFFSTACK)] + fn deref_mut(&mut self) -> &mut Cpumask { + // SAFETY: The caller owns CpumaskVar, so it is safe to deref the cpumask. + unsafe { self.ptr.as_mut() } + } + + #[cfg(not(CONFIG_CPUMASK_OFFSTACK))] + fn deref_mut(&mut self) -> &mut Cpumask { + &mut self.mask + } +} + +impl Drop for CpumaskVar { + fn drop(&mut self) { + #[cfg(CONFIG_CPUMASK_OFFSTACK)] + // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `free_cpumask_var`. + unsafe { + bindings::free_cpumask_var(self.as_raw()) + }; + } +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index de07aadd1ff5..75f78f6bfaa6 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -42,6 +42,7 @@ pub mod block; #[doc(hidden)] pub mod build_assert; +pub mod cpumask; pub mod cred; pub mod device; pub mod device_id; From ab49f64078da82ae5c362900b65a872f8a9bd585 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 25 Feb 2025 10:05:41 +0530 Subject: [PATCH 03/21] MAINTAINERS: Add entry for Rust cpumask API Update the MAINTAINERS file to include the Rust abstractions for cpumask API. Yury has indicated that he does not wish to maintain the Rust code but would like to be listed as a reviewer. Signed-off-by: Viresh Kumar Reviewed-by: Yury Norov --- MAINTAINERS | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index 96b827049501..bd7c54af4fd4 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6237,6 +6237,12 @@ L: linux-riscv@lists.infradead.org S: Maintained F: drivers/cpuidle/cpuidle-riscv-sbi.c +CPUMASK API [RUST] +M: Viresh Kumar +R: Yury Norov +S: Maintained +F: rust/kernel/cpumask.rs + CRAMFS FILESYSTEM M: Nicolas Pitre S: Maintained From b7b7b981cb037d250ad06c3a6558d69e04ed77c7 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 20 Feb 2025 16:34:00 +0530 Subject: [PATCH 04/21] rust: clk: Add helpers for Rust code Non-trivial C macros and inlined C functions cannot be used directly in the Rust code and are used via functions ("helpers") that wrap those so that they can be called from Rust. In order to prepare for adding Rust abstractions for the clock APIs, add clock helpers required by the Rust implementation. Reviewed-by: Daniel Almeida Signed-off-by: Viresh Kumar --- MAINTAINERS | 1 + rust/bindings/bindings_helper.h | 1 + rust/helpers/clk.c | 66 +++++++++++++++++++++++++++++++++ rust/helpers/helpers.c | 1 + 4 files changed, 69 insertions(+) create mode 100644 rust/helpers/clk.c diff --git a/MAINTAINERS b/MAINTAINERS index bd7c54af4fd4..608689342aaf 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5883,6 +5883,7 @@ F: include/dt-bindings/clock/ F: include/linux/clk-pr* F: include/linux/clk/ F: include/linux/of_clk.h +F: rust/helpers/clk.c X: drivers/clk/clkdev.c COMMON INTERNET FILE SYSTEM CLIENT (CIFS and SMB3) diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index ab37e1d35c70..f53d6e1a21f2 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/helpers/clk.c b/rust/helpers/clk.c new file mode 100644 index 000000000000..6d04372c9f3b --- /dev/null +++ b/rust/helpers/clk.c @@ -0,0 +1,66 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +/* + * The "inline" implementation of below helpers are only available when + * CONFIG_HAVE_CLK or CONFIG_HAVE_CLK_PREPARE aren't set. + */ +#ifndef CONFIG_HAVE_CLK +struct clk *rust_helper_clk_get(struct device *dev, const char *id) +{ + return clk_get(dev, id); +} + +void rust_helper_clk_put(struct clk *clk) +{ + clk_put(clk); +} + +int rust_helper_clk_enable(struct clk *clk) +{ + return clk_enable(clk); +} + +void rust_helper_clk_disable(struct clk *clk) +{ + clk_disable(clk); +} + +unsigned long rust_helper_clk_get_rate(struct clk *clk) +{ + return clk_get_rate(clk); +} + +int rust_helper_clk_set_rate(struct clk *clk, unsigned long rate) +{ + return clk_set_rate(clk, rate); +} +#endif + +#ifndef CONFIG_HAVE_CLK_PREPARE +int rust_helper_clk_prepare(struct clk *clk) +{ + return clk_prepare(clk); +} + +void rust_helper_clk_unprepare(struct clk *clk) +{ + clk_unprepare(clk); +} +#endif + +struct clk *rust_helper_clk_get_optional(struct device *dev, const char *id) +{ + return clk_get_optional(dev, id); +} + +int rust_helper_clk_prepare_enable(struct clk *clk) +{ + return clk_prepare_enable(clk); +} + +void rust_helper_clk_disable_unprepare(struct clk *clk) +{ + clk_disable_unprepare(clk); +} diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index e1c21eba9b15..ae595c9cd91b 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -11,6 +11,7 @@ #include "bug.c" #include "build_assert.c" #include "build_bug.c" +#include "clk.c" #include "cpumask.c" #include "cred.c" #include "device.c" From d01d7020560116876c6e39e056737b8f81f153e0 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 20 Feb 2025 16:45:47 +0530 Subject: [PATCH 05/21] rust: clk: Add initial abstractions Add initial abstractions for the clk APIs. These provide the minimal functionality needed for common use cases, making them straightforward to introduce in the first iteration. These will be used by Rust based cpufreq / OPP layers to begin with. Tested-by: Daniel Almeida Reviewed-by: Daniel Almeida Signed-off-by: Viresh Kumar --- MAINTAINERS | 1 + rust/kernel/clk.rs | 334 +++++++++++++++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 1 + 3 files changed, 336 insertions(+) create mode 100644 rust/kernel/clk.rs diff --git a/MAINTAINERS b/MAINTAINERS index 608689342aaf..12cde55579a0 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5884,6 +5884,7 @@ F: include/linux/clk-pr* F: include/linux/clk/ F: include/linux/of_clk.h F: rust/helpers/clk.c +F: rust/kernel/clk.rs X: drivers/clk/clkdev.c COMMON INTERNET FILE SYSTEM CLIENT (CIFS and SMB3) diff --git a/rust/kernel/clk.rs b/rust/kernel/clk.rs new file mode 100644 index 000000000000..6041c6d07527 --- /dev/null +++ b/rust/kernel/clk.rs @@ -0,0 +1,334 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Clock abstractions. +//! +//! C header: [`include/linux/clk.h`](srctree/include/linux/clk.h) +//! +//! Reference: + +use crate::ffi::c_ulong; + +/// The frequency unit. +/// +/// Represents a frequency in hertz, wrapping a [`c_ulong`] value. +/// +/// ## Examples +/// +/// ``` +/// use kernel::clk::Hertz; +/// +/// let hz = 1_000_000_000; +/// let rate = Hertz(hz); +/// +/// assert_eq!(rate.as_hz(), hz); +/// assert_eq!(rate, Hertz(hz)); +/// assert_eq!(rate, Hertz::from_khz(hz / 1_000)); +/// assert_eq!(rate, Hertz::from_mhz(hz / 1_000_000)); +/// assert_eq!(rate, Hertz::from_ghz(hz / 1_000_000_000)); +/// ``` +#[derive(Copy, Clone, PartialEq, Eq, Debug)] +pub struct Hertz(pub c_ulong); + +impl Hertz { + /// Create a new instance from kilohertz (kHz) + pub fn from_khz(khz: c_ulong) -> Self { + Self(khz * 1_000) + } + + /// Create a new instance from megahertz (MHz) + pub fn from_mhz(mhz: c_ulong) -> Self { + Self(mhz * 1_000_000) + } + + /// Create a new instance from gigahertz (GHz) + pub fn from_ghz(ghz: c_ulong) -> Self { + Self(ghz * 1_000_000_000) + } + + /// Get the frequency in hertz + pub fn as_hz(&self) -> c_ulong { + self.0 + } + + /// Get the frequency in kilohertz + pub fn as_khz(&self) -> c_ulong { + self.0 / 1_000 + } + + /// Get the frequency in megahertz + pub fn as_mhz(&self) -> c_ulong { + self.0 / 1_000_000 + } + + /// Get the frequency in gigahertz + pub fn as_ghz(&self) -> c_ulong { + self.0 / 1_000_000_000 + } +} + +impl From for c_ulong { + fn from(freq: Hertz) -> Self { + freq.0 + } +} + +#[cfg(CONFIG_COMMON_CLK)] +mod common_clk { + use super::Hertz; + use crate::{ + device::Device, + error::{from_err_ptr, to_result, Result}, + prelude::*, + }; + + use core::{ops::Deref, ptr}; + + /// A reference-counted clock. + /// + /// Rust abstraction for the C [`struct clk`]. + /// + /// # Invariants + /// + /// A [`Clk`] instance holds either a pointer to a valid [`struct clk`] created by the C + /// portion of the kernel or a NULL pointer. + /// + /// Instances of this type are reference-counted. Calling [`Clk::get`] ensures that the + /// allocation remains valid for the lifetime of the [`Clk`]. + /// + /// ## Examples + /// + /// The following example demonstrates how to obtain and configure a clock for a device. + /// + /// ``` + /// use kernel::c_str; + /// use kernel::clk::{Clk, Hertz}; + /// use kernel::device::Device; + /// use kernel::error::Result; + /// + /// fn configure_clk(dev: &Device) -> Result { + /// let clk = Clk::get(dev, Some(c_str!("apb_clk")))?; + /// + /// clk.prepare_enable()?; + /// + /// let expected_rate = Hertz::from_ghz(1); + /// + /// if clk.rate() != expected_rate { + /// clk.set_rate(expected_rate)?; + /// } + /// + /// clk.disable_unprepare(); + /// Ok(()) + /// } + /// ``` + /// + /// [`struct clk`]: https://docs.kernel.org/driver-api/clk.html + #[repr(transparent)] + pub struct Clk(*mut bindings::clk); + + impl Clk { + /// Gets [`Clk`] corresponding to a [`Device`] and a connection id. + /// + /// Equivalent to the kernel's [`clk_get`] API. + /// + /// [`clk_get`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_get + pub fn get(dev: &Device, name: Option<&CStr>) -> Result { + let con_id = if let Some(name) = name { + name.as_ptr() + } else { + ptr::null() + }; + + // SAFETY: It is safe to call [`clk_get`] for a valid device pointer. + // + // INVARIANT: The reference-count is decremented when [`Clk`] goes out of scope. + Ok(Self(from_err_ptr(unsafe { + bindings::clk_get(dev.as_raw(), con_id) + })?)) + } + + /// Obtain the raw [`struct clk`] pointer. + #[inline] + pub fn as_raw(&self) -> *mut bindings::clk { + self.0 + } + + /// Enable the clock. + /// + /// Equivalent to the kernel's [`clk_enable`] API. + /// + /// [`clk_enable`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_enable + #[inline] + pub fn enable(&self) -> Result { + // SAFETY: By the type invariants, self.as_raw() is a valid argument for + // [`clk_enable`]. + to_result(unsafe { bindings::clk_enable(self.as_raw()) }) + } + + /// Disable the clock. + /// + /// Equivalent to the kernel's [`clk_disable`] API. + /// + /// [`clk_disable`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_disable + #[inline] + pub fn disable(&self) { + // SAFETY: By the type invariants, self.as_raw() is a valid argument for + // [`clk_disable`]. + unsafe { bindings::clk_disable(self.as_raw()) }; + } + + /// Prepare the clock. + /// + /// Equivalent to the kernel's [`clk_prepare`] API. + /// + /// [`clk_prepare`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_prepare + #[inline] + pub fn prepare(&self) -> Result { + // SAFETY: By the type invariants, self.as_raw() is a valid argument for + // [`clk_prepare`]. + to_result(unsafe { bindings::clk_prepare(self.as_raw()) }) + } + + /// Unprepare the clock. + /// + /// Equivalent to the kernel's [`clk_unprepare`] API. + /// + /// [`clk_unprepare`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_unprepare + #[inline] + pub fn unprepare(&self) { + // SAFETY: By the type invariants, self.as_raw() is a valid argument for + // [`clk_unprepare`]. + unsafe { bindings::clk_unprepare(self.as_raw()) }; + } + + /// Prepare and enable the clock. + /// + /// Equivalent to calling [`Clk::prepare`] followed by [`Clk::enable`]. + #[inline] + pub fn prepare_enable(&self) -> Result { + // SAFETY: By the type invariants, self.as_raw() is a valid argument for + // [`clk_prepare_enable`]. + to_result(unsafe { bindings::clk_prepare_enable(self.as_raw()) }) + } + + /// Disable and unprepare the clock. + /// + /// Equivalent to calling [`Clk::disable`] followed by [`Clk::unprepare`]. + #[inline] + pub fn disable_unprepare(&self) { + // SAFETY: By the type invariants, self.as_raw() is a valid argument for + // [`clk_disable_unprepare`]. + unsafe { bindings::clk_disable_unprepare(self.as_raw()) }; + } + + /// Get clock's rate. + /// + /// Equivalent to the kernel's [`clk_get_rate`] API. + /// + /// [`clk_get_rate`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_get_rate + #[inline] + pub fn rate(&self) -> Hertz { + // SAFETY: By the type invariants, self.as_raw() is a valid argument for + // [`clk_get_rate`]. + Hertz(unsafe { bindings::clk_get_rate(self.as_raw()) }) + } + + /// Set clock's rate. + /// + /// Equivalent to the kernel's [`clk_set_rate`] API. + /// + /// [`clk_set_rate`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_set_rate + #[inline] + pub fn set_rate(&self, rate: Hertz) -> Result { + // SAFETY: By the type invariants, self.as_raw() is a valid argument for + // [`clk_set_rate`]. + to_result(unsafe { bindings::clk_set_rate(self.as_raw(), rate.as_hz()) }) + } + } + + impl Drop for Clk { + fn drop(&mut self) { + // SAFETY: By the type invariants, self.as_raw() is a valid argument for [`clk_put`]. + unsafe { bindings::clk_put(self.as_raw()) }; + } + } + + /// A reference-counted optional clock. + /// + /// A lightweight wrapper around an optional [`Clk`]. An [`OptionalClk`] represents a [`Clk`] + /// that a driver can function without but may improve performance or enable additional + /// features when available. + /// + /// # Invariants + /// + /// An [`OptionalClk`] instance encapsulates a [`Clk`] with either a valid [`struct clk`] or + /// `NULL` pointer. + /// + /// Instances of this type are reference-counted. Calling [`OptionalClk::get`] ensures that the + /// allocation remains valid for the lifetime of the [`OptionalClk`]. + /// + /// ## Examples + /// + /// The following example demonstrates how to obtain and configure an optional clock for a + /// device. The code functions correctly whether or not the clock is available. + /// + /// ``` + /// use kernel::c_str; + /// use kernel::clk::{OptionalClk, Hertz}; + /// use kernel::device::Device; + /// use kernel::error::Result; + /// + /// fn configure_clk(dev: &Device) -> Result { + /// let clk = OptionalClk::get(dev, Some(c_str!("apb_clk")))?; + /// + /// clk.prepare_enable()?; + /// + /// let expected_rate = Hertz::from_ghz(1); + /// + /// if clk.rate() != expected_rate { + /// clk.set_rate(expected_rate)?; + /// } + /// + /// clk.disable_unprepare(); + /// Ok(()) + /// } + /// ``` + /// + /// [`struct clk`]: https://docs.kernel.org/driver-api/clk.html + pub struct OptionalClk(Clk); + + impl OptionalClk { + /// Gets [`OptionalClk`] corresponding to a [`Device`] and a connection id. + /// + /// Equivalent to the kernel's [`clk_get_optional`] API. + /// + /// [`clk_get_optional`]: + /// https://docs.kernel.org/core-api/kernel-api.html#c.clk_get_optional + pub fn get(dev: &Device, name: Option<&CStr>) -> Result { + let con_id = if let Some(name) = name { + name.as_ptr() + } else { + ptr::null() + }; + + // SAFETY: It is safe to call [`clk_get_optional`] for a valid device pointer. + // + // INVARIANT: The reference-count is decremented when [`OptionalClk`] goes out of + // scope. + Ok(Self(Clk(from_err_ptr(unsafe { + bindings::clk_get_optional(dev.as_raw(), con_id) + })?))) + } + } + + // Make [`OptionalClk`] behave like [`Clk`]. + impl Deref for OptionalClk { + type Target = Clk; + + fn deref(&self) -> &Clk { + &self.0 + } + } +} + +#[cfg(CONFIG_COMMON_CLK)] +pub use common_clk::*; diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 75f78f6bfaa6..3fd7c17cbc06 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -42,6 +42,7 @@ pub mod block; #[doc(hidden)] pub mod build_assert; +pub mod clk; pub mod cpumask; pub mod cred; pub mod device; From a4e3b76e4d5c265824e686661a79f75df09c4834 Mon Sep 17 00:00:00 2001 From: Anisse Astier Date: Wed, 22 Jan 2025 14:39:52 +0100 Subject: [PATCH 06/21] rust: macros: enable use of hyphens in module names Some modules might need naming that contains hyphens "-" to match the auto-probing by name in the platform devices that comes from the device tree. But Rust identifier cannot contain hyphens, so replace them with underscores. Signed-off-by: Anisse Astier Reviewed-by: Alice Ryhl [ Viresh: Replace "-" with '-', minor commit log fix, rename variable and fix line length checkpatch warnings ] Reviewed-by: Benno Lossin Signed-off-by: Viresh Kumar --- rust/macros/module.rs | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/rust/macros/module.rs b/rust/macros/module.rs index a9418fbc9b44..6ff34096d7ee 100644 --- a/rust/macros/module.rs +++ b/rust/macros/module.rs @@ -185,7 +185,9 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream { let info = ModuleInfo::parse(&mut it); - let mut modinfo = ModInfoBuilder::new(info.name.as_ref()); + // Rust does not allow hyphens in identifiers, use underscore instead. + let ident = info.name.replace('-', "_"); + let mut modinfo = ModInfoBuilder::new(ident.as_ref()); if let Some(author) = info.author { modinfo.emit("author", &author); } @@ -310,14 +312,15 @@ mod __module_init {{ #[doc(hidden)] #[link_section = \"{initcall_section}\"] #[used] - pub static __{name}_initcall: extern \"C\" fn() -> kernel::ffi::c_int = __{name}_init; + pub static __{ident}_initcall: extern \"C\" fn() -> + kernel::ffi::c_int = __{ident}_init; #[cfg(not(MODULE))] #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)] core::arch::global_asm!( r#\".section \"{initcall_section}\", \"a\" - __{name}_initcall: - .long __{name}_init - . + __{ident}_initcall: + .long __{ident}_init - . .previous \"# ); @@ -325,7 +328,7 @@ mod __module_init {{ #[cfg(not(MODULE))] #[doc(hidden)] #[no_mangle] - pub extern \"C\" fn __{name}_init() -> kernel::ffi::c_int {{ + pub extern \"C\" fn __{ident}_init() -> kernel::ffi::c_int {{ // SAFETY: This function is inaccessible to the outside due to the double // module wrapping it. It is called exactly once by the C side via its // placement above in the initcall section. @@ -335,13 +338,13 @@ mod __module_init {{ #[cfg(not(MODULE))] #[doc(hidden)] #[no_mangle] - pub extern \"C\" fn __{name}_exit() {{ + pub extern \"C\" fn __{ident}_exit() {{ // SAFETY: // - This function is inaccessible to the outside due to the double // module wrapping it. It is called exactly once by the C side via its // unique name, - // - furthermore it is only called after `__{name}_init` has returned `0` - // (which delegates to `__init`). + // - furthermore it is only called after `__{ident}_init` has + // returned `0` (which delegates to `__init`). unsafe {{ __exit() }} }} @@ -381,6 +384,7 @@ unsafe fn __exit() {{ ", type_ = info.type_, name = info.name, + ident = ident, modinfo = modinfo.buffer, initcall_section = ".initcall6.init" ) From 3accb57d56a9bcf1cab1e908e88a235e899a2e82 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 8 Jan 2025 16:18:38 +0530 Subject: [PATCH 07/21] rust: cpu: Add from_cpu() This implements cpu::from_cpu(), which returns a reference to Device for a CPU. The C struct is created at initialization time for CPUs and is never freed and so ARef isn't returned from this function. The new helper will be used by Rust based cpufreq drivers. Signed-off-by: Viresh Kumar --- MAINTAINERS | 1 + rust/bindings/bindings_helper.h | 1 + rust/kernel/cpu.rs | 30 ++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 1 + 4 files changed, 33 insertions(+) create mode 100644 rust/kernel/cpu.rs diff --git a/MAINTAINERS b/MAINTAINERS index 12cde55579a0..475abf72869c 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6155,6 +6155,7 @@ F: include/linux/cpuhotplug.h F: include/linux/smpboot.h F: kernel/cpu.c F: kernel/smpboot.* +F: rust/kernel/cpu.rs CPU IDLE TIME MANAGEMENT FRAMEWORK M: "Rafael J. Wysocki" diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index f53d6e1a21f2..ac92c67d2c38 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/kernel/cpu.rs b/rust/kernel/cpu.rs new file mode 100644 index 000000000000..10c5c3b25873 --- /dev/null +++ b/rust/kernel/cpu.rs @@ -0,0 +1,30 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Generic CPU definitions. +//! +//! C header: [`include/linux/cpu.h`](srctree/include/linux/cpu.h) + +use crate::{bindings, device::Device, error::Result, prelude::ENODEV}; + +/// Creates a new instance of CPU's device. +/// +/// # Safety +/// +/// Reference counting is not implemented for the CPU device in the C code. When a CPU is +/// hot-unplugged, the corresponding CPU device is unregistered, but its associated memory +/// is not freed. +/// +/// Callers must ensure that the CPU device is not used after it has been unregistered. +/// This can be achieved, for example, by registering a CPU hotplug notifier and removing +/// any references to the CPU device within the notifier's callback. +pub unsafe fn from_cpu(cpu: u32) -> Result<&'static Device> { + // SAFETY: It is safe to call `get_cpu_device()` for any CPU. + let ptr = unsafe { bindings::get_cpu_device(cpu) }; + if ptr.is_null() { + return Err(ENODEV); + } + + // SAFETY: The pointer returned by `get_cpu_device()`, if not `NULL`, is a valid pointer to + // a `struct device` and is never freed by the C code. + Ok(unsafe { Device::as_ref(ptr) }) +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 3fd7c17cbc06..de0a840fcc99 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -43,6 +43,7 @@ #[doc(hidden)] pub mod build_assert; pub mod clk; +pub mod cpu; pub mod cpumask; pub mod cred; pub mod device; From 8f835497b32b59c0ba8b5e1805b7e89dd38cd9f9 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Mon, 18 Dec 2023 11:15:13 +0530 Subject: [PATCH 08/21] rust: opp: Add initial abstractions for OPP framework Introduce initial Rust abstractions for the Operating Performance Points (OPP) framework. This includes bindings for `struct dev_pm_opp` and `struct dev_pm_opp_data`, laying the groundwork for further OPP integration. Signed-off-by: Viresh Kumar --- MAINTAINERS | 1 + rust/bindings/bindings_helper.h | 1 + rust/kernel/lib.rs | 2 + rust/kernel/opp.rs | 299 ++++++++++++++++++++++++++++++++ 4 files changed, 303 insertions(+) create mode 100644 rust/kernel/opp.rs diff --git a/MAINTAINERS b/MAINTAINERS index 475abf72869c..931e418f89ed 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18165,6 +18165,7 @@ F: Documentation/devicetree/bindings/opp/ F: Documentation/power/opp.rst F: drivers/opp/ F: include/linux/pm_opp.h +F: rust/kernel/opp.rs OPL4 DRIVER M: Clemens Ladisch diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index ac92c67d2c38..529f22891e0b 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -30,6 +30,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index de0a840fcc99..ea589254b4ac 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -67,6 +67,8 @@ #[cfg(CONFIG_NET)] pub mod net; pub mod of; +#[cfg(CONFIG_PM_OPP)] +pub mod opp; pub mod page; #[cfg(CONFIG_PCI)] pub mod pci; diff --git a/rust/kernel/opp.rs b/rust/kernel/opp.rs new file mode 100644 index 000000000000..8f0493a8b6e8 --- /dev/null +++ b/rust/kernel/opp.rs @@ -0,0 +1,299 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Operating performance points. +//! +//! This module provides rust abstractions for interacting with the OPP subsystem. +//! +//! C header: [`include/linux/pm_opp.h`](srctree/include/linux/pm_opp.h) +//! +//! Reference: + +use crate::{ + clk::Hertz, + device::Device, + error::{code::*, to_result, Result}, + ffi::c_ulong, + types::{ARef, AlwaysRefCounted, Opaque}, +}; + +use core::ptr; + +/// The voltage unit. +/// +/// Represents voltage in microvolts, wrapping a [`c_ulong`] value. +/// +/// ## Examples +/// +/// ``` +/// use kernel::opp::MicroVolt; +/// +/// let raw = 90500; +/// let volt = MicroVolt(raw); +/// +/// assert_eq!(usize::from(volt), raw); +/// assert_eq!(volt, MicroVolt(raw)); +/// ``` +#[derive(Copy, Clone, PartialEq, Eq, Debug)] +pub struct MicroVolt(pub c_ulong); + +impl From for c_ulong { + #[inline] + fn from(volt: MicroVolt) -> Self { + volt.0 + } +} + +/// The power unit. +/// +/// Represents power in microwatts, wrapping a [`c_ulong`] value. +/// +/// ## Examples +/// +/// ``` +/// use kernel::opp::MicroWatt; +/// +/// let raw = 1000000; +/// let power = MicroWatt(raw); +/// +/// assert_eq!(usize::from(power), raw); +/// assert_eq!(power, MicroWatt(raw)); +/// ``` +#[derive(Copy, Clone, PartialEq, Eq, Debug)] +pub struct MicroWatt(pub c_ulong); + +impl From for c_ulong { + #[inline] + fn from(power: MicroWatt) -> Self { + power.0 + } +} + +/// Handle for a dynamically created [`OPP`]. +/// +/// The associated [`OPP`] is automatically removed when the [`Token`] is dropped. +/// +/// ## Examples +/// +/// The following example demonstrates how to create an [`OPP`] dynamically. +/// +/// ``` +/// use kernel::clk::Hertz; +/// use kernel::device::Device; +/// use kernel::error::Result; +/// use kernel::opp::{Data, MicroVolt, Token}; +/// use kernel::types::ARef; +/// +/// fn create_opp(dev: &ARef, freq: Hertz, volt: MicroVolt, level: u32) -> Result { +/// let data = Data::new(freq, volt, level, false); +/// +/// // OPP is removed once token goes out of scope. +/// data.add_opp(dev) +/// } +/// ``` +pub struct Token { + dev: ARef, + freq: Hertz, +} + +impl Token { + /// Dynamically adds an [`OPP`] and returns a [`Token`] that removes it on drop. + fn new(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) })?; + Ok(Self { + dev: dev.clone(), + freq: data.freq(), + }) + } +} + +impl Drop for Token { + fn drop(&mut self) { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + unsafe { bindings::dev_pm_opp_remove(self.dev.as_raw(), self.freq.into()) }; + } +} + +/// OPP data. +/// +/// Rust abstraction for the C `struct dev_pm_opp_data`, used to define operating performance +/// points (OPPs) dynamically. +/// +/// ## Examples +/// +/// The following example demonstrates how to create an [`OPP`] with [`Data`]. +/// +/// ``` +/// use kernel::clk::Hertz; +/// use kernel::device::Device; +/// use kernel::error::Result; +/// use kernel::opp::{Data, MicroVolt, Token}; +/// use kernel::types::ARef; +/// +/// fn create_opp(dev: &ARef, freq: Hertz, volt: MicroVolt, level: u32) -> Result { +/// let data = Data::new(freq, volt, level, false); +/// +/// // OPP is removed once token goes out of scope. +/// data.add_opp(dev) +/// } +/// ``` +#[repr(transparent)] +pub struct Data(bindings::dev_pm_opp_data); + +impl Data { + /// Creates a new instance of [`Data`]. + /// + /// This can be used to define a dynamic OPP to be added to a device. + pub fn new(freq: Hertz, volt: MicroVolt, level: u32, turbo: bool) -> Self { + Self(bindings::dev_pm_opp_data { + turbo, + freq: freq.into(), + u_volt: volt.into(), + level, + }) + } + + /// Adds an [`OPP`] dynamically. + /// + /// Returns a [`Token`] that ensures the OPP is automatically removed + /// when it goes out of scope. + #[inline] + pub fn add_opp(self, dev: &ARef) -> Result { + Token::new(dev, self) + } + + /// Returns the frequency associated with this OPP data. + #[inline] + fn freq(&self) -> Hertz { + Hertz(self.0.freq) + } +} + +/// A reference-counted Operating performance point (OPP). +/// +/// Rust abstraction for the C `struct dev_pm_opp`. +/// +/// # Invariants +/// +/// The pointer stored in `Self` is non-null and valid for the lifetime of the [`OPP`]. +/// +/// Instances of this type are reference-counted. The reference count is incremented by the +/// `dev_pm_opp_get` function and decremented by `dev_pm_opp_put`. The Rust type `ARef` +/// represents a pointer that owns a reference count on the [`OPP`]. +/// +/// A reference to the [`OPP`], &[`OPP`], isn't refcounted by the Rust code. +#[repr(transparent)] +pub struct OPP(Opaque); + +/// SAFETY: It is okay to send the ownership of [`OPP`] across thread boundaries. +unsafe impl Send for OPP {} + +/// SAFETY: It is okay to access [`OPP`] through shared references from other threads because we're +/// either accessing properties that don't change or that are properly synchronised by C code. +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 an owned reference to a [`OPP`] from a valid pointer. + /// + /// The refcount is incremented by the C code and will be decremented by `dec_ref` when the + /// [`ARef`] object is dropped. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid and the refcount of the [`OPP`] is incremented. + /// The caller must also ensure that it doesn't explicitly drop the refcount of the [`OPP`], as + /// the returned [`ARef`] object takes over the refcount increment on the underlying object and + /// the same will be dropped along with it. + pub unsafe fn from_raw_opp_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 reference-count is decremented when [`OPP`] goes out of scope. + Ok(unsafe { ARef::from_raw(ptr.cast()) }) + } + + /// Creates a reference to a [`OPP`] from a valid pointer. + /// + /// The refcount is not updated by the Rust API unless the returned reference is converted to + /// an [`ARef`] object. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid and remains valid for the duration of `'a`. + #[inline] + pub unsafe fn from_raw_opp<'a>(ptr: *mut bindings::dev_pm_opp) -> Result<&'a Self> { + // SAFETY: The caller guarantees that the pointer is not dangling and stays valid for the + // duration of 'a. The cast is okay because [`OPP`] is `repr(transparent)`. + Ok(unsafe { &*ptr.cast() }) + } + + #[inline] + fn as_raw(&self) -> *mut bindings::dev_pm_opp { + self.0.get() + } + + /// Returns the frequency of an [`OPP`]. + pub fn freq(&self, index: Option) -> Hertz { + 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. + Hertz(unsafe { bindings::dev_pm_opp_get_freq_indexed(self.as_raw(), index) }) + } + + /// Returns the voltage of an [`OPP`]. + #[inline] + pub fn voltage(&self) -> MicroVolt { + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to + // use it. + MicroVolt(unsafe { bindings::dev_pm_opp_get_voltage(self.as_raw()) }) + } + + /// Returns the level of an [`OPP`]. + #[inline] + 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_raw()) } + } + + /// Returns the power of an [`OPP`]. + #[inline] + pub fn power(&self) -> MicroWatt { + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to + // use it. + MicroWatt(unsafe { bindings::dev_pm_opp_get_power(self.as_raw()) }) + } + + /// Returns the required pstate of an [`OPP`]. + #[inline] + 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_raw(), index) } + } + + /// Returns true if the [`OPP`] is turbo. + #[inline] + 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_raw()) } + } +} From d52c7e868fbc134d88bb04d5909f2df2f9da5202 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Mon, 18 Dec 2023 11:15:13 +0530 Subject: [PATCH 09/21] rust: opp: Add abstractions for the OPP table Introduce Rust abstractions for `struct opp_table`, enabling access to OPP tables from Rust. Signed-off-by: Viresh Kumar --- rust/kernel/opp.rs | 487 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 486 insertions(+), 1 deletion(-) diff --git a/rust/kernel/opp.rs b/rust/kernel/opp.rs index 8f0493a8b6e8..26a0ecfe046a 100644 --- a/rust/kernel/opp.rs +++ b/rust/kernel/opp.rs @@ -10,8 +10,9 @@ use crate::{ clk::Hertz, + cpumask::{Cpumask, CpumaskVar}, device::Device, - error::{code::*, to_result, Result}, + error::{code::*, from_err_ptr, to_result, Error, Result}, ffi::c_ulong, types::{ARef, AlwaysRefCounted, Opaque}, }; @@ -171,6 +172,469 @@ fn freq(&self) -> Hertz { } } +/// [`OPP`] search options. +/// +/// ## Examples +/// +/// Defines how to search for an [`OPP`] in a [`Table`] relative to a frequency. +/// +/// ``` +/// use kernel::clk::Hertz; +/// use kernel::error::Result; +/// use kernel::opp::{OPP, SearchType, Table}; +/// use kernel::types::ARef; +/// +/// fn find_opp(table: &Table, freq: Hertz) -> Result> { +/// let opp = table.opp_from_freq(freq, Some(true), None, SearchType::Exact)?; +/// +/// pr_info!("OPP frequency is: {:?}\n", opp.freq(None)); +/// pr_info!("OPP voltage is: {:?}\n", opp.voltage()); +/// pr_info!("OPP level is: {}\n", opp.level()); +/// pr_info!("OPP power is: {:?}\n", opp.power()); +/// +/// Ok(opp) +/// } +/// ``` +#[derive(Copy, Clone, Debug, Eq, PartialEq)] +pub enum SearchType { + /// Match the exact frequency. + Exact, + /// Find the highest frequency less than or equal to the given value. + Floor, + /// Find the lowest frequency greater than or equal to the given value. + Ceil, +} + +/// A reference-counted OPP table. +/// +/// Rust abstraction for the C `struct opp_table`. +/// +/// # Invariants +/// +/// The pointer stored in `Self` is non-null and valid for the lifetime of the [`Table`]. +/// +/// Instances of this type are reference-counted. +/// +/// ## Examples +/// +/// The following example demonstrates how to get OPP [`Table`] for a [`Cpumask`] and set its +/// frequency. +/// +/// ``` +/// use kernel::clk::Hertz; +/// use kernel::cpumask::Cpumask; +/// use kernel::device::Device; +/// use kernel::error::Result; +/// use kernel::opp::Table; +/// use kernel::types::ARef; +/// +/// fn get_table(dev: &ARef, mask: &mut Cpumask, freq: Hertz) -> Result { +/// let mut opp_table = Table::from_of_cpumask(dev, mask)?; +/// +/// if opp_table.opp_count()? == 0 { +/// return Err(EINVAL); +/// } +/// +/// pr_info!("Max transition latency is: {} ns\n", opp_table.max_transition_latency_ns()); +/// pr_info!("Suspend frequency is: {:?}\n", opp_table.suspend_freq()); +/// +/// opp_table.set_rate(freq)?; +/// Ok(opp_table) +/// } +/// ``` +pub struct Table { + ptr: *mut bindings::opp_table, + dev: ARef, + #[allow(dead_code)] + em: bool, + #[allow(dead_code)] + of: bool, + cpus: Option, +} + +/// SAFETY: It is okay to send ownership of [`Table`] across thread boundaries. +unsafe impl Send for Table {} + +/// SAFETY: It is okay to access [`Table`] through shared references from other threads because +/// we're either accessing properties that don't change or that are properly synchronised by C code. +unsafe impl Sync for Table {} + +impl Table { + /// Creates a new reference-counted [`Table`] from a raw pointer. + /// + /// # Safety + /// + /// Callers must ensure that `ptr` is valid and non-null. + unsafe fn from_raw_table(ptr: *mut bindings::opp_table, dev: &ARef) -> Self { + // SAFETY: By the safety requirements, ptr is valid and its refcount will be incremented. + // + // INVARIANT: The reference-count is decremented when [`Table`] goes out of scope. + unsafe { bindings::dev_pm_opp_get_opp_table_ref(ptr) }; + + Self { + ptr, + dev: dev.clone(), + em: false, + of: false, + cpus: None, + } + } + + /// Creates a new reference-counted [`Table`] instance for a [`Device`]. + pub fn from_dev(dev: &Device) -> Result { + // SAFETY: The requirements are satisfied by the existence of the [`Device`] and its safety + // requirements. + // + // INVARIANT: The reference-count is incremented by the C code and is decremented when + // [`Table`] goes out of scope. + let ptr = from_err_ptr(unsafe { bindings::dev_pm_opp_get_opp_table(dev.as_raw()) })?; + + Ok(Self { + ptr, + dev: dev.into(), + em: false, + of: false, + cpus: None, + }) + } + + /// Creates a new reference-counted [`Table`] instance for a [`Device`] based on device tree + /// entries. + #[cfg(CONFIG_OF)] + pub fn from_of(dev: &ARef, index: i32) -> Result { + // SAFETY: The requirements are satisfied by the existence of the [`Device`] and its safety + // requirements. + // + // INVARIANT: The reference-count is incremented by the C code and is decremented when + // [`Table`] goes out of scope. + to_result(unsafe { bindings::dev_pm_opp_of_add_table_indexed(dev.as_raw(), index) })?; + + // Get the newly created [`Table`]. + let mut table = Self::from_dev(dev)?; + table.of = true; + + Ok(table) + } + + /// Remove device tree based [`Table`]. + #[cfg(CONFIG_OF)] + #[inline] + fn remove_of(&self) { + // SAFETY: The requirements are satisfied by the existence of the [`Device`] and its safety + // requirements. We took the reference from [`from_of`] earlier, it is safe to drop the + // same now. + unsafe { bindings::dev_pm_opp_of_remove_table(self.dev.as_raw()) }; + } + + /// Creates a new reference-counted [`Table`] instance for a [`Cpumask`] based on device tree + /// entries. + #[cfg(CONFIG_OF)] + pub fn from_of_cpumask(dev: &Device, cpumask: &mut Cpumask) -> Result { + // SAFETY: The cpumask is valid and the returned pointer will be owned by the [`Table`] + // instance. + // + // INVARIANT: The reference-count is incremented by the C code and is decremented when + // [`Table`] goes out of scope. + to_result(unsafe { bindings::dev_pm_opp_of_cpumask_add_table(cpumask.as_raw()) })?; + + // Fetch the newly created table. + let mut table = Self::from_dev(dev)?; + table.cpus = Some(CpumaskVar::try_clone(cpumask)?); + + Ok(table) + } + + /// Remove device tree based [`Table`] for a [`Cpumask`]. + #[cfg(CONFIG_OF)] + #[inline] + fn remove_of_cpumask(&self, cpumask: &Cpumask) { + // SAFETY: The cpumask is valid and we took the reference from [`from_of_cpumask`] earlier, + // it is safe to drop the same now. + unsafe { bindings::dev_pm_opp_of_cpumask_remove_table(cpumask.as_raw()) }; + } + + /// Returns the number of [`OPP`]s in the [`Table`]. + pub fn opp_count(&self) -> Result { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + let ret = unsafe { bindings::dev_pm_opp_get_opp_count(self.dev.as_raw()) }; + if ret < 0 { + Err(Error::from_errno(ret)) + } else { + Ok(ret as u32) + } + } + + /// Returns max clock latency (in nanoseconds) of the [`OPP`]s in the [`Table`]. + #[inline] + pub fn max_clock_latency_ns(&self) -> usize { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + unsafe { bindings::dev_pm_opp_get_max_clock_latency(self.dev.as_raw()) } + } + + /// Returns max volt latency (in nanoseconds) of the [`OPP`]s in the [`Table`]. + #[inline] + pub fn max_volt_latency_ns(&self) -> usize { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + unsafe { bindings::dev_pm_opp_get_max_volt_latency(self.dev.as_raw()) } + } + + /// Returns max transition latency (in nanoseconds) of the [`OPP`]s in the [`Table`]. + #[inline] + pub fn max_transition_latency_ns(&self) -> usize { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + unsafe { bindings::dev_pm_opp_get_max_transition_latency(self.dev.as_raw()) } + } + + /// Returns the suspend [`OPP`]'s frequency. + #[inline] + pub fn suspend_freq(&self) -> Hertz { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + Hertz(unsafe { bindings::dev_pm_opp_get_suspend_opp_freq(self.dev.as_raw()) }) + } + + /// Synchronizes regulators used by the [`Table`]. + #[inline] + pub fn sync_regulators(&self) -> Result { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + to_result(unsafe { bindings::dev_pm_opp_sync_regulators(self.dev.as_raw()) }) + } + + /// Gets sharing CPUs. + #[inline] + pub fn sharing_cpus(dev: &Device, cpumask: &mut Cpumask) -> Result { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + to_result(unsafe { bindings::dev_pm_opp_get_sharing_cpus(dev.as_raw(), cpumask.as_raw()) }) + } + + /// Sets sharing CPUs. + pub fn set_sharing_cpus(&mut self, cpumask: &mut Cpumask) -> Result { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + to_result(unsafe { + bindings::dev_pm_opp_set_sharing_cpus(self.dev.as_raw(), cpumask.as_raw()) + })?; + + if let Some(mask) = self.cpus.as_mut() { + // Update the cpumask as this will be used while removing the table. + cpumask.copy(mask); + } + + Ok(()) + } + + /// Gets sharing CPUs from device tree. + #[cfg(CONFIG_OF)] + #[inline] + pub fn of_sharing_cpus(dev: &Device, cpumask: &mut Cpumask) -> Result { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + to_result(unsafe { + bindings::dev_pm_opp_of_get_sharing_cpus(dev.as_raw(), cpumask.as_raw()) + }) + } + + /// Updates the voltage value for an [`OPP`]. + #[inline] + pub fn adjust_voltage( + &self, + freq: Hertz, + volt: MicroVolt, + volt_min: MicroVolt, + volt_max: MicroVolt, + ) -> Result { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + to_result(unsafe { + bindings::dev_pm_opp_adjust_voltage( + self.dev.as_raw(), + freq.into(), + volt.into(), + volt_min.into(), + volt_max.into(), + ) + }) + } + + /// Configures device with [`OPP`] matching the frequency value. + #[inline] + pub fn set_rate(&self, freq: Hertz) -> Result { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + to_result(unsafe { bindings::dev_pm_opp_set_rate(self.dev.as_raw(), freq.into()) }) + } + + /// Configures device with [`OPP`]. + #[inline] + pub fn set_opp(&self, opp: &OPP) -> Result { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + to_result(unsafe { bindings::dev_pm_opp_set_opp(self.dev.as_raw(), opp.as_raw()) }) + } + + /// Finds [`OPP`] based on frequency. + pub fn opp_from_freq( + &self, + freq: Hertz, + available: Option, + index: Option, + stype: SearchType, + ) -> Result> { + let raw_dev = self.dev.as_raw(); + let index = index.unwrap_or(0); + let mut rate = freq.into(); + + let ptr = from_err_ptr(match stype { + SearchType::Exact => { + if let Some(available) = available { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and + // its safety requirements. The returned pointer will be owned by the new + // [`OPP`] instance. + unsafe { + bindings::dev_pm_opp_find_freq_exact_indexed( + raw_dev, rate, index, available, + ) + } + } else { + return Err(EINVAL); + } + } + + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. The returned pointer will be owned by the new [`OPP`] instance. + SearchType::Ceil => unsafe { + bindings::dev_pm_opp_find_freq_ceil_indexed(raw_dev, &mut rate, index) + }, + + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. The returned pointer will be owned by the new [`OPP`] instance. + SearchType::Floor => unsafe { + bindings::dev_pm_opp_find_freq_floor_indexed(raw_dev, &mut rate, index) + }, + })?; + + // SAFETY: The `ptr` is guaranteed by the C code to be valid. + unsafe { OPP::from_raw_opp_owned(ptr) } + } + + /// Finds [`OPP`] based on level. + pub fn opp_from_level(&self, mut level: u32, stype: SearchType) -> Result> { + let raw_dev = self.dev.as_raw(); + + let ptr = from_err_ptr(match stype { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. The returned pointer will be owned by the new [`OPP`] instance. + SearchType::Exact => unsafe { bindings::dev_pm_opp_find_level_exact(raw_dev, level) }, + + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. The returned pointer will be owned by the new [`OPP`] instance. + SearchType::Ceil => unsafe { + bindings::dev_pm_opp_find_level_ceil(raw_dev, &mut level) + }, + + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. The returned pointer will be owned by the new [`OPP`] instance. + SearchType::Floor => unsafe { + bindings::dev_pm_opp_find_level_floor(raw_dev, &mut level) + }, + })?; + + // SAFETY: The `ptr` is guaranteed by the C code to be valid. + unsafe { OPP::from_raw_opp_owned(ptr) } + } + + /// Finds [`OPP`] based on bandwidth. + pub fn opp_from_bw(&self, mut bw: u32, index: i32, stype: SearchType) -> Result> { + let raw_dev = self.dev.as_raw(); + + let ptr = from_err_ptr(match stype { + // The OPP core doesn't support this yet. + SearchType::Exact => return Err(EINVAL), + + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. The returned pointer will be owned by the new [`OPP`] instance. + SearchType::Ceil => unsafe { + bindings::dev_pm_opp_find_bw_ceil(raw_dev, &mut bw, index) + }, + + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. The returned pointer will be owned by the new [`OPP`] instance. + SearchType::Floor => unsafe { + bindings::dev_pm_opp_find_bw_floor(raw_dev, &mut bw, index) + }, + })?; + + // SAFETY: The `ptr` is guaranteed by the C code to be valid. + unsafe { OPP::from_raw_opp_owned(ptr) } + } + + /// Enables the [`OPP`]. + #[inline] + pub fn enable_opp(&self, freq: Hertz) -> Result { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + to_result(unsafe { bindings::dev_pm_opp_enable(self.dev.as_raw(), freq.into()) }) + } + + /// Disables the [`OPP`]. + #[inline] + pub fn disable_opp(&self, freq: Hertz) -> Result { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + to_result(unsafe { bindings::dev_pm_opp_disable(self.dev.as_raw(), freq.into()) }) + } + + /// Registers with the Energy model. + #[cfg(CONFIG_OF)] + pub fn of_register_em(&mut self, cpumask: &mut Cpumask) -> Result { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + to_result(unsafe { + bindings::dev_pm_opp_of_register_em(self.dev.as_raw(), cpumask.as_raw()) + })?; + + self.em = true; + Ok(()) + } + + /// Unregisters with the Energy model. + #[cfg(all(CONFIG_OF, CONFIG_ENERGY_MODEL))] + #[inline] + fn of_unregister_em(&self) { + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. We registered with the EM framework earlier, it is safe to unregister now. + unsafe { bindings::em_dev_unregister_perf_domain(self.dev.as_raw()) }; + } +} + +impl Drop for Table { + fn drop(&mut self) { + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe + // to relinquish it now. + unsafe { bindings::dev_pm_opp_put_opp_table(self.ptr) }; + + #[cfg(CONFIG_OF)] + { + #[cfg(CONFIG_ENERGY_MODEL)] + if self.em { + self.of_unregister_em(); + } + + if self.of { + self.remove_of(); + } else if let Some(cpumask) = self.cpus.take() { + self.remove_of_cpumask(&cpumask); + } + } + } +} + /// A reference-counted Operating performance point (OPP). /// /// Rust abstraction for the C `struct dev_pm_opp`. @@ -184,6 +648,27 @@ fn freq(&self) -> Hertz { /// represents a pointer that owns a reference count on the [`OPP`]. /// /// A reference to the [`OPP`], &[`OPP`], isn't refcounted by the Rust code. +/// +/// ## Examples +/// +/// The following example demonstrates how to get [`OPP`] corresponding to a frequency value and +/// configure the device with it. +/// +/// ``` +/// use kernel::clk::Hertz; +/// use kernel::error::Result; +/// use kernel::opp::{SearchType, Table}; +/// +/// fn configure_opp(table: &Table, freq: Hertz) -> Result { +/// let opp = table.opp_from_freq(freq, Some(true), None, SearchType::Exact)?; +/// +/// if opp.freq(None) != freq { +/// return Err(EINVAL); +/// } +/// +/// table.set_opp(&opp) +/// } +/// ``` #[repr(transparent)] pub struct OPP(Opaque); From ce32e2d47ce6c472a931eabe53f841c62b6abfe5 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Mon, 18 Dec 2023 11:15:13 +0530 Subject: [PATCH 10/21] rust: opp: Add abstractions for the configuration options Introduce Rust abstractions for the OPP core configuration options, enabling safe access to various configurable aspects of the OPP framework. Signed-off-by: Viresh Kumar --- rust/kernel/opp.rs | 295 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 293 insertions(+), 2 deletions(-) diff --git a/rust/kernel/opp.rs b/rust/kernel/opp.rs index 26a0ecfe046a..5293d878cb55 100644 --- a/rust/kernel/opp.rs +++ b/rust/kernel/opp.rs @@ -12,12 +12,29 @@ clk::Hertz, cpumask::{Cpumask, CpumaskVar}, device::Device, - error::{code::*, from_err_ptr, to_result, Error, Result}, + error::{code::*, from_err_ptr, from_result, to_result, Error, Result, VTABLE_DEFAULT_ERROR}, ffi::c_ulong, + prelude::*, + str::CString, types::{ARef, AlwaysRefCounted, Opaque}, }; -use core::ptr; +use core::{marker::PhantomData, ptr}; + +use macros::vtable; + +/// Creates a null-terminated slice of pointers to [`Cstring`]s. +fn to_c_str_array(names: &[CString]) -> Result> { + // Allocated a null-terminated vector of pointers. + let mut list = KVec::with_capacity(names.len() + 1, GFP_KERNEL)?; + + for name in names.iter() { + list.push(name.as_ptr() as _, GFP_KERNEL)?; + } + + list.push(ptr::null(), GFP_KERNEL)?; + Ok(list) +} /// The voltage unit. /// @@ -205,6 +222,280 @@ pub enum SearchType { Ceil, } +/// OPP configuration callbacks. +/// +/// Implement this trait to customize OPP clock and regulator setup for your device. +#[vtable] +pub trait ConfigOps { + /// This is typically used to scale clocks when transitioning between OPPs. + #[inline] + fn config_clks(_dev: &Device, _table: &Table, _opp: &OPP, _scaling_down: bool) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// This provides access to the old and new OPPs, allowing for safe regulator adjustments. + #[inline] + fn config_regulators( + _dev: &Device, + _opp_old: &OPP, + _opp_new: &OPP, + _data: *mut *mut bindings::regulator, + _count: u32, + ) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } +} + +/// OPP configuration token. +/// +/// Returned by the OPP core when configuration is applied to a [`Device`]. The associated +/// configuration is automatically cleared when the token is dropped. +pub struct ConfigToken(i32); + +impl Drop for ConfigToken { + fn drop(&mut self) { + // SAFETY: This is the same token value returned by the C code via `dev_pm_opp_set_config`. + unsafe { bindings::dev_pm_opp_clear_config(self.0) }; + } +} + +/// OPP configurations. +/// +/// Rust abstraction for the C `struct dev_pm_opp_config`. +/// +/// ## Examples +/// +/// The following example demonstrates how to set OPP property-name configuration for a [`Device`]. +/// +/// ``` +/// use kernel::device::Device; +/// use kernel::error::Result; +/// use kernel::opp::{Config, ConfigOps, ConfigToken}; +/// use kernel::str::CString; +/// use kernel::types::ARef; +/// use kernel::macros::vtable; +/// +/// #[derive(Default)] +/// struct Driver; +/// +/// #[vtable] +/// impl ConfigOps for Driver {} +/// +/// fn configure(dev: &ARef) -> Result { +/// let name = CString::try_from_fmt(fmt!("{}", "slow"))?; +/// +/// // The OPP configuration is cleared once the [`ConfigToken`] goes out of scope. +/// Config::::new() +/// .set_prop_name(name)? +/// .set(dev) +/// } +/// ``` +#[derive(Default)] +pub struct Config +where + T: Default, +{ + clk_names: Option>, + prop_name: Option, + regulator_names: Option>, + supported_hw: Option>, + + // Tuple containing (required device, index) + required_dev: Option<(ARef, u32)>, + _data: PhantomData, +} + +impl Config { + /// Creates a new instance of [`Config`]. + #[inline] + pub fn new() -> Self { + Self::default() + } + + /// Initializes clock names. + pub fn set_clk_names(mut self, names: KVec) -> Result { + if self.clk_names.is_some() { + return Err(EBUSY); + } + + if names.is_empty() { + return Err(EINVAL); + } + + self.clk_names = Some(names); + Ok(self) + } + + /// Initializes property name. + pub fn set_prop_name(mut self, name: CString) -> Result { + if self.prop_name.is_some() { + return Err(EBUSY); + } + + self.prop_name = Some(name); + Ok(self) + } + + /// Initializes regulator names. + pub fn set_regulator_names(mut self, names: KVec) -> Result { + if self.regulator_names.is_some() { + return Err(EBUSY); + } + + if names.is_empty() { + return Err(EINVAL); + } + + self.regulator_names = Some(names); + + Ok(self) + } + + /// Initializes required devices. + pub fn set_required_dev(mut self, dev: ARef, index: u32) -> Result { + if self.required_dev.is_some() { + return Err(EBUSY); + } + + self.required_dev = Some((dev, index)); + Ok(self) + } + + /// Initializes supported hardware. + pub fn set_supported_hw(mut self, hw: KVec) -> Result { + if self.supported_hw.is_some() { + return Err(EBUSY); + } + + if hw.is_empty() { + return Err(EINVAL); + } + + self.supported_hw = Some(hw); + Ok(self) + } + + /// Sets the configuration with the OPP core. + /// + /// The returned [`ConfigToken`] will remove the configuration when dropped. + pub fn set(self, dev: &Device) -> Result { + let (_clk_list, clk_names) = match &self.clk_names { + Some(x) => { + let list = to_c_str_array(x)?; + let ptr = list.as_ptr(); + (Some(list), ptr) + } + None => (None, ptr::null()), + }; + + let (_regulator_list, regulator_names) = match &self.regulator_names { + Some(x) => { + let list = to_c_str_array(x)?; + let ptr = list.as_ptr(); + (Some(list), ptr) + } + None => (None, ptr::null()), + }; + + let prop_name = self + .prop_name + .as_ref() + .map_or(ptr::null(), |p| p.as_char_ptr()); + + let (supported_hw, supported_hw_count) = self + .supported_hw + .as_ref() + .map_or((ptr::null(), 0), |hw| (hw.as_ptr(), hw.len() as u32)); + + let (required_dev, required_dev_index) = self + .required_dev + .as_ref() + .map_or((ptr::null_mut(), 0), |(dev, idx)| (dev.as_raw(), *idx)); + + let mut config = bindings::dev_pm_opp_config { + clk_names, + config_clks: if T::HAS_CONFIG_CLKS { + Some(Self::config_clks) + } else { + None + }, + prop_name, + regulator_names, + config_regulators: if T::HAS_CONFIG_REGULATORS { + Some(Self::config_regulators) + } else { + None + }, + supported_hw, + supported_hw_count, + + required_dev, + required_dev_index, + }; + + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. The OPP core guarantees not to access fields of [`Config`] after this call + // and so we don't need to save a copy of them for future use. + let ret = unsafe { bindings::dev_pm_opp_set_config(dev.as_raw(), &mut config) }; + if ret < 0 { + Err(Error::from_errno(ret)) + } else { + Ok(ConfigToken(ret)) + } + } + + /// Config's clk callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn config_clks( + dev: *mut bindings::device, + opp_table: *mut bindings::opp_table, + opp: *mut bindings::dev_pm_opp, + _data: *mut kernel::ffi::c_void, + scaling_down: bool, + ) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: 'dev' is guaranteed by the C code to be valid. + let dev = unsafe { Device::get_device(dev) }; + T::config_clks( + &dev, + // SAFETY: 'opp_table' is guaranteed by the C code to be valid. + &unsafe { Table::from_raw_table(opp_table, &dev) }, + // SAFETY: 'opp' is guaranteed by the C code to be valid. + unsafe { OPP::from_raw_opp(opp)? }, + scaling_down, + ) + .map(|()| 0) + }) + } + + /// Config's regulator callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn config_regulators( + dev: *mut bindings::device, + old_opp: *mut bindings::dev_pm_opp, + new_opp: *mut bindings::dev_pm_opp, + regulators: *mut *mut bindings::regulator, + count: kernel::ffi::c_uint, + ) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: 'dev' is guaranteed by the C code to be valid. + let dev = unsafe { Device::get_device(dev) }; + T::config_regulators( + &dev, + // SAFETY: 'old_opp' is guaranteed by the C code to be valid. + unsafe { OPP::from_raw_opp(old_opp)? }, + // SAFETY: 'new_opp' is guaranteed by the C code to be valid. + unsafe { OPP::from_raw_opp(new_opp)? }, + regulators, + count, + ) + .map(|()| 0) + }) + } +} + /// A reference-counted OPP table. /// /// Rust abstraction for the C `struct opp_table`. From 2207856ff0bc8d953d6e89bda70b8978c2de8bab Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 7 Jan 2025 12:51:08 +0530 Subject: [PATCH 11/21] rust: cpufreq: Add initial abstractions for cpufreq framework Introduce initial Rust abstractions for the cpufreq core. This includes basic representations for cpufreq flags, relation types, and the cpufreq table. Signed-off-by: Viresh Kumar --- MAINTAINERS | 1 + rust/bindings/bindings_helper.h | 1 + rust/helpers/cpufreq.c | 10 + rust/helpers/helpers.c | 1 + rust/kernel/cpufreq.rs | 365 ++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 2 + 6 files changed, 380 insertions(+) create mode 100644 rust/helpers/cpufreq.c create mode 100644 rust/kernel/cpufreq.rs diff --git a/MAINTAINERS b/MAINTAINERS index 931e418f89ed..aa56eacbda71 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6142,6 +6142,7 @@ F: drivers/cpufreq/ F: include/linux/cpufreq.h F: include/linux/sched/cpufreq.h F: kernel/sched/cpufreq*.c +F: rust/kernel/cpufreq.rs F: tools/testing/selftests/cpufreq/ CPU HOTPLUG diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index 529f22891e0b..7c1d78f68076 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/helpers/cpufreq.c b/rust/helpers/cpufreq.c new file mode 100644 index 000000000000..7c1343c4d65e --- /dev/null +++ b/rust/helpers/cpufreq.c @@ -0,0 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +#ifdef CONFIG_CPU_FREQ +void rust_helper_cpufreq_register_em_with_opp(struct cpufreq_policy *policy) +{ + cpufreq_register_em_with_opp(policy); +} +#endif diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index ae595c9cd91b..df1fcfb3adf3 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -12,6 +12,7 @@ #include "build_assert.c" #include "build_bug.c" #include "clk.c" +#include "cpufreq.c" #include "cpumask.c" #include "cred.c" #include "device.c" diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs new file mode 100644 index 000000000000..94fa63bda75a --- /dev/null +++ b/rust/kernel/cpufreq.rs @@ -0,0 +1,365 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! CPU frequency scaling. +//! +//! This module provides rust abstractions for interacting with the cpufreq subsystem. +//! +//! C header: [`include/linux/cpufreq.h`](srctree/include/linux/cpufreq.h) +//! +//! Reference: + +use crate::{ + clk::Hertz, + error::{code::*, to_result, Result}, + ffi::c_ulong, + prelude::*, + types::Opaque, +}; + +use core::{ops::Deref, pin::Pin}; + +/// Default transition latency value in nanoseconds. +pub const ETERNAL_LATENCY_NS: u32 = bindings::CPUFREQ_ETERNAL as u32; + +/// CPU frequency driver flags. +pub mod flags { + /// Driver needs to update internal limits even if frequency remains unchanged. + pub const NEED_UPDATE_LIMITS: u16 = 1 << 0; + + /// Platform where constants like `loops_per_jiffy` are unaffected by frequency changes. + pub const CONST_LOOPS: u16 = 1 << 1; + + /// Register driver as a thermal cooling device automatically. + pub const IS_COOLING_DEV: u16 = 1 << 2; + + /// Supports multiple clock domains with per-policy governors in `cpu/cpuN/cpufreq/`. + pub const HAVE_GOVERNOR_PER_POLICY: u16 = 1 << 3; + + /// Allows post-change notifications outside of the `target()` routine. + pub const ASYNC_NOTIFICATION: u16 = 1 << 4; + + /// Ensure CPU starts at a valid frequency from the driver's freq-table. + pub const NEED_INITIAL_FREQ_CHECK: u16 = 1 << 5; + + /// Disallow governors with `dynamic_switching` capability. + pub const NO_AUTO_DYNAMIC_SWITCHING: u16 = 1 << 6; +} + +/// Relations from the C code. +const CPUFREQ_RELATION_L: u32 = 0; +const CPUFREQ_RELATION_H: u32 = 1; +const CPUFREQ_RELATION_C: u32 = 2; + +/// Can be used with any of the above values. +const CPUFREQ_RELATION_E: u32 = 1 << 2; + +/// CPU frequency selection relations. +/// +/// CPU frequency selection relations, each optionally marked as "efficient". +#[derive(Copy, Clone, Debug, Eq, PartialEq)] +pub enum Relation { + /// Select the lowest frequency at or above target. + Low(bool), + /// Select the highest frequency below or at target. + High(bool), + /// Select the closest frequency to the target. + Close(bool), +} + +impl Relation { + // Construct from a C-compatible `u32` value. + fn new(val: u32) -> Result { + let efficient = val & CPUFREQ_RELATION_E != 0; + + Ok(match val & !CPUFREQ_RELATION_E { + CPUFREQ_RELATION_L => Self::Low(efficient), + CPUFREQ_RELATION_H => Self::High(efficient), + CPUFREQ_RELATION_C => Self::Close(efficient), + _ => return Err(EINVAL), + }) + } +} + +impl From for u32 { + // Convert to a C-compatible `u32` value. + fn from(rel: Relation) -> Self { + let (mut val, efficient) = match rel { + Relation::Low(e) => (CPUFREQ_RELATION_L, e), + Relation::High(e) => (CPUFREQ_RELATION_H, e), + Relation::Close(e) => (CPUFREQ_RELATION_C, e), + }; + + if efficient { + val |= CPUFREQ_RELATION_E; + } + + val + } +} + +/// Policy data. +/// +/// Rust abstraction for the C `struct cpufreq_policy_data`. +/// +/// # Invariants +/// +/// A [`PolicyData`] instance always corresponds to a valid C `struct cpufreq_policy_data`. +/// +/// The callers must ensure that the `struct cpufreq_policy_data` is valid for access and remains +/// valid for the lifetime of the returned reference. +#[repr(transparent)] +pub struct PolicyData(Opaque); + +impl PolicyData { + /// Creates a mutable reference to an existing `struct cpufreq_policy_data` pointer. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid for writing and remains valid for the lifetime + /// of the returned reference. + #[inline] + pub unsafe fn from_raw_mut<'a>(ptr: *mut bindings::cpufreq_policy_data) -> &'a mut Self { + // SAFETY: Guaranteed by the safety requirements of the function. + // + // INVARIANT: The caller ensures that `ptr` is valid for writing and remains valid for the + // lifetime of the returned reference. + unsafe { &mut *ptr.cast() } + } + + /// Returns a raw pointer to the underlying C `cpufreq_policy_data`. + #[inline] + pub fn as_raw(&self) -> *mut bindings::cpufreq_policy_data { + let this: *const Self = self; + this.cast_mut().cast() + } + + /// Wrapper for `cpufreq_generic_frequency_table_verify`. + #[inline] + pub fn generic_verify(&self) -> Result { + // SAFETY: By the type invariant, the pointer stored in `self` is valid. + to_result(unsafe { bindings::cpufreq_generic_frequency_table_verify(self.as_raw()) }) + } +} + +/// The frequency table index. +/// +/// Represents index with a frequency table. +/// +/// # Invariants +/// +/// The index must correspond to a valid entry in the [`Table`] it is used for. +#[derive(Copy, Clone, PartialEq, Eq, Debug)] +pub struct TableIndex(usize); + +impl TableIndex { + /// Creates an instance of [`TableIndex`]. + /// + /// # Safety + /// + /// The caller must ensure that `index` correspond to a valid entry in the [`Table`] it is used + /// for. + pub unsafe fn new(index: usize) -> Self { + // INVARIANT: The caller ensures that `index` correspond to a valid entry in the [`Table`]. + Self(index) + } +} + +impl From for usize { + #[inline] + fn from(index: TableIndex) -> Self { + index.0 + } +} + +/// CPU frequency table. +/// +/// Rust abstraction for the C `struct cpufreq_frequency_table`. +/// +/// # Invariants +/// +/// A [`Table`] instance always corresponds to a valid C `struct cpufreq_frequency_table`. +/// +/// The callers must ensure that the `struct cpufreq_frequency_table` is valid for access and +/// remains valid for the lifetime of the returned reference. +/// +/// ## Examples +/// +/// The following example demonstrates how to read a frequency value from [`Table`]. +/// +/// ``` +/// use kernel::cpufreq::{Policy, TableIndex}; +/// +/// fn show_freq(policy: &Policy) -> Result { +/// let table = policy.freq_table()?; +/// +/// // SAFETY: Index is a valid entry in the table. +/// let index = unsafe { TableIndex::new(0) }; +/// +/// pr_info!("The frequency at index 0 is: {:?}\n", table.freq(index)?); +/// pr_info!("The flags at index 0 is: {}\n", table.flags(index)); +/// pr_info!("The data at index 0 is: {}\n", table.data(index)); +/// Ok(()) +/// } +/// ``` +#[repr(transparent)] +pub struct Table(Opaque); + +impl Table { + /// Creates a reference to an existing C `struct cpufreq_frequency_table` pointer. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid for reading and remains valid for the lifetime + /// of the returned reference. + #[inline] + pub unsafe fn from_raw<'a>(ptr: *const bindings::cpufreq_frequency_table) -> &'a Self { + // SAFETY: Guaranteed by the safety requirements of the function. + // + // INVARIANT: The caller ensures that `ptr` is valid for reading and remains valid for the + // lifetime of the returned reference. + unsafe { &*ptr.cast() } + } + + /// Returns the raw mutable pointer to the C `struct cpufreq_frequency_table`. + #[inline] + pub fn as_raw(&self) -> *mut bindings::cpufreq_frequency_table { + let this: *const Self = self; + this.cast_mut().cast() + } + + /// Returns frequency at `index` in the [`Table`]. + #[inline] + pub fn freq(&self, index: TableIndex) -> Result { + // SAFETY: By the type invariant, the pointer stored in `self` is valid and `index` is + // guaranteed to be valid by its safety requirements. + Ok(Hertz::from_khz(unsafe { + (*self.as_raw().add(index.into())).frequency.try_into()? + })) + } + + /// Returns flags at `index` in the [`Table`]. + #[inline] + pub fn flags(&self, index: TableIndex) -> u32 { + // SAFETY: By the type invariant, the pointer stored in `self` is valid and `index` is + // guaranteed to be valid by its safety requirements. + unsafe { (*self.as_raw().add(index.into())).flags } + } + + /// Returns data at `index` in the [`Table`]. + #[inline] + pub fn data(&self, index: TableIndex) -> u32 { + // SAFETY: By the type invariant, the pointer stored in `self` is valid and `index` is + // guaranteed to be valid by its safety requirements. + unsafe { (*self.as_raw().add(index.into())).driver_data } + } +} + +/// CPU frequency table owned and pinned in memory, created from a [`TableBuilder`]. +pub struct TableBox { + entries: Pin>, +} + +impl TableBox { + /// Constructs a new [`TableBox`] from a [`KVec`] of entries. + /// + /// # Errors + /// + /// Returns `EINVAL` if the entries list is empty. + #[inline] + fn new(entries: KVec) -> Result { + if entries.is_empty() { + return Err(EINVAL); + } + + Ok(Self { + // Pin the entries to memory, since we are passing its pointer to the C code. + entries: Pin::new(entries), + }) + } + + /// Returns a raw pointer to the underlying C `cpufreq_frequency_table`. + #[inline] + fn as_raw(&self) -> *const bindings::cpufreq_frequency_table { + // The pointer is valid until the table gets dropped. + self.entries.as_ptr() + } +} + +impl Deref for TableBox { + type Target = Table; + + fn deref(&self) -> &Self::Target { + // SAFETY: The caller owns TableBox, it is safe to deref. + unsafe { Self::Target::from_raw(self.as_raw()) } + } +} + +/// CPU frequency table builder. +/// +/// This is used by the CPU frequency drivers to build a frequency table dynamically. +/// +/// ## Examples +/// +/// The following example demonstrates how to create a CPU frequency table. +/// +/// ``` +/// use kernel::cpufreq::{TableBuilder, TableIndex}; +/// use kernel::clk::Hertz; +/// +/// let mut builder = TableBuilder::new(); +/// +/// // Adds few entries to the table. +/// builder.add(Hertz::from_mhz(700), 0, 1).unwrap(); +/// builder.add(Hertz::from_mhz(800), 2, 3).unwrap(); +/// builder.add(Hertz::from_mhz(900), 4, 5).unwrap(); +/// builder.add(Hertz::from_ghz(1), 6, 7).unwrap(); +/// +/// let table = builder.to_table().unwrap(); +/// +/// // SAFETY: Index values correspond to valid entries in the table. +/// let (index0, index2) = unsafe { (TableIndex::new(0), TableIndex::new(2)) }; +/// +/// assert_eq!(table.freq(index0), Ok(Hertz::from_mhz(700))); +/// assert_eq!(table.flags(index0), 0); +/// assert_eq!(table.data(index0), 1); +/// +/// assert_eq!(table.freq(index2), Ok(Hertz::from_mhz(900))); +/// assert_eq!(table.flags(index2), 4); +/// assert_eq!(table.data(index2), 5); +/// ``` +#[derive(Default)] +#[repr(transparent)] +pub struct TableBuilder { + entries: KVec, +} + +impl TableBuilder { + /// Creates a new instance of [`TableBuilder`]. + #[inline] + pub fn new() -> Self { + Self { + entries: KVec::new(), + } + } + + /// Adds a new entry to the table. + pub fn add(&mut self, freq: Hertz, flags: u32, driver_data: u32) -> Result { + // Adds the new entry at the end of the vector. + Ok(self.entries.push( + bindings::cpufreq_frequency_table { + flags, + driver_data, + frequency: freq.as_khz() as u32, + }, + GFP_KERNEL, + )?) + } + + /// Consumes the [`TableBuilder`] and returns [`TableBox`]. + pub fn to_table(mut self) -> Result { + // Add last entry to the table. + self.add(Hertz(c_ulong::MAX), 0, 0)?; + + TableBox::new(self.entries) + } +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index ea589254b4ac..133ebee4f9d3 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -44,6 +44,8 @@ pub mod build_assert; pub mod clk; pub mod cpu; +#[cfg(CONFIG_CPU_FREQ)] +pub mod cpufreq; pub mod cpumask; pub mod cred; pub mod device; From 6ebdd7c9317737123b260a24e2780018008f1295 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 7 May 2025 15:32:25 +0530 Subject: [PATCH 12/21] rust: cpufreq: Extend abstractions for policy and driver ops Extend the cpufreq abstractions to include support for policy handling and driver operations. Signed-off-by: Viresh Kumar --- rust/kernel/cpufreq.rs | 463 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 461 insertions(+), 2 deletions(-) diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs index 94fa63bda75a..1bc208b91822 100644 --- a/rust/kernel/cpufreq.rs +++ b/rust/kernel/cpufreq.rs @@ -10,13 +10,25 @@ use crate::{ clk::Hertz, - error::{code::*, to_result, Result}, + cpumask, + device::Device, + error::{code::*, from_err_ptr, to_result, Result, VTABLE_DEFAULT_ERROR}, ffi::c_ulong, prelude::*, + types::ForeignOwnable, types::Opaque, }; -use core::{ops::Deref, pin::Pin}; +#[cfg(CONFIG_COMMON_CLK)] +use crate::clk::Clk; + +use core::{ + ops::{Deref, DerefMut}, + pin::Pin, + ptr, +}; + +use macros::vtable; /// Default transition latency value in nanoseconds. pub const ETERNAL_LATENCY_NS: u32 = bindings::CPUFREQ_ETERNAL as u32; @@ -363,3 +375,450 @@ pub fn to_table(mut self) -> Result { TableBox::new(self.entries) } } + +/// CPU frequency policy. +/// +/// Rust abstraction for the C `struct cpufreq_policy`. +/// +/// # Invariants +/// +/// A [`Policy`] instance always corresponds to a valid C `struct cpufreq_policy`. +/// +/// The callers must ensure that the `struct cpufreq_policy` is valid for access and remains valid +/// for the lifetime of the returned reference. +/// +/// ## Examples +/// +/// The following example demonstrates how to create a CPU frequency table. +/// +/// ``` +/// use kernel::cpufreq::{ETERNAL_LATENCY_NS, Policy}; +/// +/// fn update_policy(policy: &mut Policy) { +/// policy +/// .set_dvfs_possible_from_any_cpu(true) +/// .set_fast_switch_possible(true) +/// .set_transition_latency_ns(ETERNAL_LATENCY_NS); +/// +/// pr_info!("The policy details are: {:?}\n", (policy.cpu(), policy.cur())); +/// } +/// ``` +#[repr(transparent)] +pub struct Policy(Opaque); + +impl Policy { + /// Creates a reference to an existing `struct cpufreq_policy` pointer. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid for reading and remains valid for the lifetime + /// of the returned reference. + #[inline] + pub unsafe fn from_raw<'a>(ptr: *const bindings::cpufreq_policy) -> &'a Self { + // SAFETY: Guaranteed by the safety requirements of the function. + // + // INVARIANT: The caller ensures that `ptr` is valid for reading and remains valid for the + // lifetime of the returned reference. + unsafe { &*ptr.cast() } + } + + /// Creates a mutable reference to an existing `struct cpufreq_policy` pointer. + /// + /// # Safety + /// + /// The caller must ensure that `ptr` is valid for writing and remains valid for the lifetime + /// of the returned reference. + #[inline] + pub unsafe fn from_raw_mut<'a>(ptr: *mut bindings::cpufreq_policy) -> &'a mut Self { + // SAFETY: Guaranteed by the safety requirements of the function. + // + // INVARIANT: The caller ensures that `ptr` is valid for writing and remains valid for the + // lifetime of the returned reference. + unsafe { &mut *ptr.cast() } + } + + /// Returns a raw mutable pointer to the C `struct cpufreq_policy`. + #[inline] + fn as_raw(&self) -> *mut bindings::cpufreq_policy { + let this: *const Self = self; + this.cast_mut().cast() + } + + #[inline] + fn as_ref(&self) -> &bindings::cpufreq_policy { + // SAFETY: By the type invariant, the pointer stored in `self` is valid. + unsafe { &*self.as_raw() } + } + + #[inline] + fn as_mut_ref(&mut self) -> &mut bindings::cpufreq_policy { + // SAFETY: By the type invariant, the pointer stored in `self` is valid. + unsafe { &mut *self.as_raw() } + } + + /// Returns the primary CPU for the [`Policy`]. + #[inline] + pub fn cpu(&self) -> u32 { + self.as_ref().cpu + } + + /// Returns the minimum frequency for the [`Policy`]. + #[inline] + pub fn min(&self) -> Hertz { + Hertz::from_khz(self.as_ref().min as usize) + } + + /// Set the minimum frequency for the [`Policy`]. + #[inline] + pub fn set_min(&mut self, min: Hertz) -> &mut Self { + self.as_mut_ref().min = min.as_khz() as u32; + self + } + + /// Returns the maximum frequency for the [`Policy`]. + #[inline] + pub fn max(&self) -> Hertz { + Hertz::from_khz(self.as_ref().max as usize) + } + + /// Set the maximum frequency for the [`Policy`]. + #[inline] + pub fn set_max(&mut self, max: Hertz) -> &mut Self { + self.as_mut_ref().max = max.as_khz() as u32; + self + } + + /// Returns the current frequency for the [`Policy`]. + #[inline] + pub fn cur(&self) -> Hertz { + Hertz::from_khz(self.as_ref().cur as usize) + } + + /// Returns the suspend frequency for the [`Policy`]. + #[inline] + pub fn suspend_freq(&self) -> Hertz { + Hertz::from_khz(self.as_ref().suspend_freq as usize) + } + + /// Sets the suspend frequency for the [`Policy`]. + #[inline] + pub fn set_suspend_freq(&mut self, freq: Hertz) -> &mut Self { + self.as_mut_ref().suspend_freq = freq.as_khz() as u32; + self + } + + /// Provides a wrapper to the generic suspend routine. + #[inline] + pub fn generic_suspend(&mut self) -> Result { + // SAFETY: By the type invariant, the pointer stored in `self` is valid. + to_result(unsafe { bindings::cpufreq_generic_suspend(self.as_mut_ref()) }) + } + + /// Provides a wrapper to the generic get routine. + #[inline] + pub fn generic_get(&self) -> Result { + // SAFETY: By the type invariant, the pointer stored in `self` is valid. + Ok(unsafe { bindings::cpufreq_generic_get(self.cpu()) }) + } + + /// Provides a wrapper to the register with energy model using the OPP core. + #[cfg(CONFIG_PM_OPP)] + #[inline] + pub fn register_em_opp(&mut self) { + // SAFETY: By the type invariant, the pointer stored in `self` is valid. + unsafe { bindings::cpufreq_register_em_with_opp(self.as_mut_ref()) }; + } + + /// Gets [`cpumask::Cpumask`] for a cpufreq [`Policy`]. + #[inline] + pub fn cpus(&mut self) -> &mut cpumask::Cpumask { + // SAFETY: The pointer to `cpus` is valid for writing and remains valid for the lifetime of + // the returned reference. + unsafe { cpumask::CpumaskVar::as_mut_ref(&mut self.as_mut_ref().cpus) } + } + + /// Sets clock for the [`Policy`]. + /// + /// # Safety + /// + /// The caller must guarantee that the returned [`Clk`] is not dropped while it is getting used + /// by the C code. + #[cfg(CONFIG_COMMON_CLK)] + pub unsafe fn set_clk(&mut self, dev: &Device, name: Option<&CStr>) -> Result { + let clk = Clk::get(dev, name)?; + self.as_mut_ref().clk = clk.as_raw(); + Ok(clk) + } + + /// Allows / disallows frequency switching code to run on any CPU. + #[inline] + pub fn set_dvfs_possible_from_any_cpu(&mut self, val: bool) -> &mut Self { + self.as_mut_ref().dvfs_possible_from_any_cpu = val; + self + } + + /// Returns if fast switching of frequencies is possible or not. + #[inline] + pub fn fast_switch_possible(&self) -> bool { + self.as_ref().fast_switch_possible + } + + /// Enables / disables fast frequency switching. + #[inline] + pub fn set_fast_switch_possible(&mut self, val: bool) -> &mut Self { + self.as_mut_ref().fast_switch_possible = val; + self + } + + /// Sets transition latency (in nanoseconds) for the [`Policy`]. + #[inline] + pub fn set_transition_latency_ns(&mut self, latency_ns: u32) -> &mut Self { + self.as_mut_ref().cpuinfo.transition_latency = latency_ns; + self + } + + /// Sets cpuinfo `min_freq`. + #[inline] + pub fn set_cpuinfo_min_freq(&mut self, min_freq: Hertz) -> &mut Self { + self.as_mut_ref().cpuinfo.min_freq = min_freq.as_khz() as u32; + self + } + + /// Sets cpuinfo `max_freq`. + #[inline] + pub fn set_cpuinfo_max_freq(&mut self, max_freq: Hertz) -> &mut Self { + self.as_mut_ref().cpuinfo.max_freq = max_freq.as_khz() as u32; + self + } + + /// Set `transition_delay_us`, i.e. the minimum time between successive frequency change + /// requests. + #[inline] + pub fn set_transition_delay_us(&mut self, transition_delay_us: u32) -> &mut Self { + self.as_mut_ref().transition_delay_us = transition_delay_us; + self + } + + /// Returns reference to the CPU frequency [`Table`] for the [`Policy`]. + pub fn freq_table(&self) -> Result<&Table> { + if self.as_ref().freq_table.is_null() { + return Err(EINVAL); + } + + // SAFETY: The `freq_table` is guaranteed to be valid for reading and remains valid for the + // lifetime of the returned reference. + Ok(unsafe { Table::from_raw(self.as_ref().freq_table) }) + } + + /// Sets the CPU frequency [`Table`] for the [`Policy`]. + /// + /// # Safety + /// + /// The caller must guarantee that the [`Table`] is not dropped while it is getting used by the + /// C code. + #[inline] + pub unsafe fn set_freq_table(&mut self, table: &Table) -> &mut Self { + self.as_mut_ref().freq_table = table.as_raw(); + self + } + + /// Returns the [`Policy`]'s private data. + pub fn data(&mut self) -> Option<::Borrowed<'_>> { + if self.as_ref().driver_data.is_null() { + None + } else { + // SAFETY: The data is earlier set from [`set_data`]. + Some(unsafe { T::borrow(self.as_ref().driver_data) }) + } + } + + /// Sets the private data of the [`Policy`] using a foreign-ownable wrapper. + /// + /// # Errors + /// + /// Returns `EBUSY` if private data is already set. + fn set_data(&mut self, data: T) -> Result { + if self.as_ref().driver_data.is_null() { + // Transfer the ownership of the data to the foreign interface. + self.as_mut_ref().driver_data = ::into_foreign(data) as _; + Ok(()) + } else { + Err(EBUSY) + } + } + + /// Clears and returns ownership of the private data. + fn clear_data(&mut self) -> Option { + if self.as_ref().driver_data.is_null() { + None + } else { + let data = Some( + // 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. + unsafe { ::from_foreign(self.as_ref().driver_data) }, + ); + self.as_mut_ref().driver_data = ptr::null_mut(); + data + } + } +} + +/// CPU frequency policy created from a CPU number. +/// +/// This struct represents the CPU frequency policy obtained for a specific CPU, providing safe +/// access to the underlying `cpufreq_policy` and ensuring proper cleanup when the `PolicyCpu` is +/// dropped. +struct PolicyCpu<'a>(&'a mut Policy); + +impl<'a> PolicyCpu<'a> { + fn from_cpu(cpu: u32) -> Result { + // SAFETY: It is safe to call `cpufreq_cpu_get` for any valid CPU. + let ptr = from_err_ptr(unsafe { bindings::cpufreq_cpu_get(cpu) })?; + + Ok(Self( + // SAFETY: The `ptr` is guaranteed to be valid and remains valid for the lifetime of + // the returned reference. + unsafe { Policy::from_raw_mut(ptr) }, + )) + } +} + +impl<'a> Deref for PolicyCpu<'a> { + type Target = Policy; + + fn deref(&self) -> &Self::Target { + self.0 + } +} + +impl<'a> DerefMut for PolicyCpu<'a> { + fn deref_mut(&mut self) -> &mut Policy { + self.0 + } +} + +impl<'a> Drop for PolicyCpu<'a> { + fn drop(&mut self) { + // SAFETY: The underlying pointer is guaranteed to be valid for the lifetime of `self`. + unsafe { bindings::cpufreq_cpu_put(self.0.as_raw()) }; + } +} + +/// CPU frequency driver. +/// +/// Implement this trait to provide a CPU frequency driver and its callbacks. +/// +/// Reference: +#[vtable] +pub trait Driver { + /// Driver's name. + const NAME: &'static CStr; + + /// Driver's flags. + const FLAGS: u16; + + /// Boost support. + const BOOST_ENABLED: bool; + + /// Policy specific data. + /// + /// Require that `PData` implements `ForeignOwnable`. We guarantee to never move the underlying + /// wrapped data structure. + type PData: ForeignOwnable; + + /// Driver's `init` callback. + fn init(policy: &mut Policy) -> Result; + + /// Driver's `exit` callback. + fn exit(_policy: &mut Policy, _data: Option) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `online` callback. + fn online(_policy: &mut Policy) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `offline` callback. + fn offline(_policy: &mut Policy) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `suspend` callback. + fn suspend(_policy: &mut Policy) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `resume` callback. + fn resume(_policy: &mut Policy) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `ready` callback. + fn ready(_policy: &mut Policy) { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `verify` callback. + fn verify(data: &mut PolicyData) -> Result; + + /// Driver's `setpolicy` callback. + fn setpolicy(_policy: &mut Policy) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `target` callback. + fn target(_policy: &mut Policy, _target_freq: u32, _relation: Relation) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `target_index` callback. + fn target_index(_policy: &mut Policy, _index: TableIndex) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `fast_switch` callback. + fn fast_switch(_policy: &mut Policy, _target_freq: u32) -> u32 { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `adjust_perf` callback. + fn adjust_perf(_policy: &mut Policy, _min_perf: usize, _target_perf: usize, _capacity: usize) { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `get_intermediate` callback. + fn get_intermediate(_policy: &mut Policy, _index: TableIndex) -> u32 { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `target_intermediate` callback. + fn target_intermediate(_policy: &mut Policy, _index: TableIndex) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `get` callback. + fn get(_policy: &mut Policy) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `update_limits` callback. + fn update_limits(_policy: &mut Policy) { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `bios_limit` callback. + fn bios_limit(_policy: &mut Policy, _limit: &mut u32) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `set_boost` callback. + fn set_boost(_policy: &mut Policy, _state: i32) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Driver's `register_em` callback. + fn register_em(_policy: &mut Policy) { + build_error!(VTABLE_DEFAULT_ERROR) + } +} From c6af9a1191d042839e56abff69e8b0302d117988 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 24 Jan 2024 12:36:33 +0530 Subject: [PATCH 13/21] rust: cpufreq: Extend abstractions for driver registration Extend the cpufreq abstractions to support driver registration from Rust. Reviewed-by: Danilo Krummrich Signed-off-by: Viresh Kumar --- rust/kernel/cpufreq.rs | 503 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 500 insertions(+), 3 deletions(-) diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs index 1bc208b91822..09b856bb297b 100644 --- a/rust/kernel/cpufreq.rs +++ b/rust/kernel/cpufreq.rs @@ -11,9 +11,10 @@ use crate::{ clk::Hertz, cpumask, - device::Device, - error::{code::*, from_err_ptr, to_result, Result, VTABLE_DEFAULT_ERROR}, - ffi::c_ulong, + device::{Bound, Device}, + devres::Devres, + error::{code::*, from_err_ptr, from_result, to_result, Result, VTABLE_DEFAULT_ERROR}, + ffi::{c_char, c_ulong}, prelude::*, types::ForeignOwnable, types::Opaque, @@ -23,6 +24,9 @@ use crate::clk::Clk; use core::{ + cell::UnsafeCell, + marker::PhantomData, + mem::MaybeUninit, ops::{Deref, DerefMut}, pin::Pin, ptr, @@ -30,6 +34,9 @@ use macros::vtable; +/// Maximum length of CPU frequency driver's name. +const CPUFREQ_NAME_LEN: usize = bindings::CPUFREQ_NAME_LEN as usize; + /// Default transition latency value in nanoseconds. pub const ETERNAL_LATENCY_NS: u32 = bindings::CPUFREQ_ETERNAL as u32; @@ -822,3 +829,493 @@ fn register_em(_policy: &mut Policy) { build_error!(VTABLE_DEFAULT_ERROR) } } + +/// CPU frequency driver Registration. +/// +/// ## Examples +/// +/// The following example demonstrates how to register a cpufreq driver. +/// +/// ``` +/// use kernel::{ +/// cpufreq, +/// c_str, +/// device::{Core, Device}, +/// macros::vtable, +/// of, platform, +/// sync::Arc, +/// }; +/// struct SampleDevice; +/// +/// #[derive(Default)] +/// struct SampleDriver; +/// +/// #[vtable] +/// impl cpufreq::Driver for SampleDriver { +/// const NAME: &'static CStr = c_str!("cpufreq-sample"); +/// const FLAGS: u16 = cpufreq::flags::NEED_INITIAL_FREQ_CHECK | cpufreq::flags::IS_COOLING_DEV; +/// const BOOST_ENABLED: bool = true; +/// +/// type PData = Arc; +/// +/// fn init(policy: &mut cpufreq::Policy) -> Result { +/// // Initialize here +/// Ok(Arc::new(SampleDevice, GFP_KERNEL)?) +/// } +/// +/// fn exit(_policy: &mut cpufreq::Policy, _data: Option) -> Result { +/// Ok(()) +/// } +/// +/// fn suspend(policy: &mut cpufreq::Policy) -> Result { +/// policy.generic_suspend() +/// } +/// +/// fn verify(data: &mut cpufreq::PolicyData) -> Result { +/// data.generic_verify() +/// } +/// +/// fn target_index(policy: &mut cpufreq::Policy, index: cpufreq::TableIndex) -> Result { +/// // Update CPU frequency +/// Ok(()) +/// } +/// +/// fn get(policy: &mut cpufreq::Policy) -> Result { +/// policy.generic_get() +/// } +/// } +/// +/// impl platform::Driver for SampleDriver { +/// type IdInfo = (); +/// const OF_ID_TABLE: Option> = None; +/// +/// fn probe( +/// pdev: &platform::Device, +/// _id_info: Option<&Self::IdInfo>, +/// ) -> Result>> { +/// cpufreq::Registration::::new_foreign_owned(pdev.as_ref())?; +/// Ok(KBox::new(Self {}, GFP_KERNEL)?.into()) +/// } +/// } +/// ``` +#[repr(transparent)] +pub struct Registration(KBox>, PhantomData); + +/// SAFETY: `Registration` doesn't offer any methods or access to fields when shared between threads +/// or CPUs, so it is safe to share it. +unsafe impl Sync for Registration {} + +#[allow(clippy::non_send_fields_in_send_ty)] +/// SAFETY: Registration with and unregistration from the cpufreq subsystem can happen from any +/// thread. +unsafe impl Send for Registration {} + +impl Registration { + const VTABLE: bindings::cpufreq_driver = bindings::cpufreq_driver { + name: Self::copy_name(T::NAME), + boost_enabled: T::BOOST_ENABLED, + flags: T::FLAGS, + + // Initialize mandatory callbacks. + init: Some(Self::init_callback), + verify: Some(Self::verify_callback), + + // Initialize optional callbacks based on the traits of `T`. + setpolicy: if T::HAS_SETPOLICY { + Some(Self::setpolicy_callback) + } else { + None + }, + target: if T::HAS_TARGET { + Some(Self::target_callback) + } else { + None + }, + target_index: if T::HAS_TARGET_INDEX { + Some(Self::target_index_callback) + } else { + None + }, + fast_switch: if T::HAS_FAST_SWITCH { + Some(Self::fast_switch_callback) + } else { + None + }, + adjust_perf: if T::HAS_ADJUST_PERF { + Some(Self::adjust_perf_callback) + } else { + None + }, + get_intermediate: if T::HAS_GET_INTERMEDIATE { + Some(Self::get_intermediate_callback) + } else { + None + }, + target_intermediate: if T::HAS_TARGET_INTERMEDIATE { + Some(Self::target_intermediate_callback) + } else { + None + }, + get: if T::HAS_GET { + Some(Self::get_callback) + } else { + None + }, + update_limits: if T::HAS_UPDATE_LIMITS { + Some(Self::update_limits_callback) + } else { + None + }, + bios_limit: if T::HAS_BIOS_LIMIT { + Some(Self::bios_limit_callback) + } else { + None + }, + online: if T::HAS_ONLINE { + Some(Self::online_callback) + } else { + None + }, + offline: if T::HAS_OFFLINE { + Some(Self::offline_callback) + } else { + None + }, + exit: if T::HAS_EXIT { + Some(Self::exit_callback) + } else { + None + }, + suspend: if T::HAS_SUSPEND { + Some(Self::suspend_callback) + } else { + None + }, + resume: if T::HAS_RESUME { + Some(Self::resume_callback) + } else { + None + }, + ready: if T::HAS_READY { + Some(Self::ready_callback) + } else { + None + }, + set_boost: if T::HAS_SET_BOOST { + Some(Self::set_boost_callback) + } else { + None + }, + register_em: if T::HAS_REGISTER_EM { + Some(Self::register_em_callback) + } else { + None + }, + // SAFETY: All zeros is a valid value for `bindings::cpufreq_driver`. + ..unsafe { MaybeUninit::zeroed().assume_init() } + }; + + const fn copy_name(name: &'static CStr) -> [c_char; CPUFREQ_NAME_LEN] { + let src = name.as_bytes_with_nul(); + let mut dst = [0; CPUFREQ_NAME_LEN]; + + build_assert!(src.len() <= CPUFREQ_NAME_LEN); + + let mut i = 0; + while i < src.len() { + dst[i] = src[i]; + i += 1; + } + + dst + } + + /// Registers a CPU frequency driver with the cpufreq core. + pub fn new() -> Result { + // We can't use `&Self::VTABLE` directly because the cpufreq core modifies some fields in + // the C `struct cpufreq_driver`, which requires a mutable reference. + let mut drv = KBox::new(UnsafeCell::new(Self::VTABLE), GFP_KERNEL)?; + + // SAFETY: `drv` is guaranteed to be valid for the lifetime of `Registration`. + to_result(unsafe { bindings::cpufreq_register_driver(drv.get_mut()) })?; + + Ok(Self(drv, PhantomData)) + } + + /// Same as [`Registration::new`], but does not return a [`Registration`] instance. + /// + /// Instead the [`Registration`] is owned by [`Devres`] and will be revoked / dropped, once the + /// device is detached. + pub fn new_foreign_owned(dev: &Device) -> Result { + Devres::new_foreign_owned(dev, Self::new()?, GFP_KERNEL) + } +} + +/// CPU frequency driver callbacks. +impl Registration { + /// Driver's `init` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn init_callback(ptr: *mut bindings::cpufreq_policy) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + + let data = T::init(policy)?; + policy.set_data(data)?; + Ok(0) + }) + } + + /// Driver's `exit` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn exit_callback(ptr: *mut bindings::cpufreq_policy) { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + + let data = policy.clear_data(); + let _ = T::exit(policy, data); + } + + /// Driver's `online` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn online_callback(ptr: *mut bindings::cpufreq_policy) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + T::online(policy).map(|()| 0) + }) + } + + /// Driver's `offline` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn offline_callback(ptr: *mut bindings::cpufreq_policy) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + T::offline(policy).map(|()| 0) + }) + } + + /// Driver's `suspend` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn suspend_callback(ptr: *mut bindings::cpufreq_policy) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + T::suspend(policy).map(|()| 0) + }) + } + + /// Driver's `resume` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn resume_callback(ptr: *mut bindings::cpufreq_policy) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + T::resume(policy).map(|()| 0) + }) + } + + /// Driver's `ready` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn ready_callback(ptr: *mut bindings::cpufreq_policy) { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + T::ready(policy); + } + + /// Driver's `verify` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn verify_callback(ptr: *mut bindings::cpufreq_policy_data) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let data = unsafe { PolicyData::from_raw_mut(ptr) }; + T::verify(data).map(|()| 0) + }) + } + + /// Driver's `setpolicy` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn setpolicy_callback(ptr: *mut bindings::cpufreq_policy) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + T::setpolicy(policy).map(|()| 0) + }) + } + + /// Driver's `target` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn target_callback( + ptr: *mut bindings::cpufreq_policy, + target_freq: u32, + relation: u32, + ) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + T::target(policy, target_freq, Relation::new(relation)?).map(|()| 0) + }) + } + + /// Driver's `target_index` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn target_index_callback( + ptr: *mut bindings::cpufreq_policy, + index: u32, + ) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + + // SAFETY: The C code guarantees that `index` corresponds to a valid entry in the + // frequency table. + let index = unsafe { TableIndex::new(index as usize) }; + + T::target_index(policy, index).map(|()| 0) + }) + } + + /// Driver's `fast_switch` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn fast_switch_callback( + ptr: *mut bindings::cpufreq_policy, + target_freq: u32, + ) -> kernel::ffi::c_uint { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + T::fast_switch(policy, target_freq) + } + + /// Driver's `adjust_perf` callback. + extern "C" fn adjust_perf_callback( + cpu: u32, + min_perf: usize, + target_perf: usize, + capacity: usize, + ) { + if let Ok(mut policy) = PolicyCpu::from_cpu(cpu) { + T::adjust_perf(&mut policy, min_perf, target_perf, capacity); + } + } + + /// Driver's `get_intermediate` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn get_intermediate_callback( + ptr: *mut bindings::cpufreq_policy, + index: u32, + ) -> kernel::ffi::c_uint { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + + // SAFETY: The C code guarantees that `index` corresponds to a valid entry in the + // frequency table. + let index = unsafe { TableIndex::new(index as usize) }; + + T::get_intermediate(policy, index) + } + + /// Driver's `target_intermediate` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn target_intermediate_callback( + ptr: *mut bindings::cpufreq_policy, + index: u32, + ) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + + // SAFETY: The C code guarantees that `index` corresponds to a valid entry in the + // frequency table. + let index = unsafe { TableIndex::new(index as usize) }; + + T::target_intermediate(policy, index).map(|()| 0) + }) + } + + /// Driver's `get` callback. + extern "C" fn get_callback(cpu: u32) -> kernel::ffi::c_uint { + PolicyCpu::from_cpu(cpu).map_or(0, |mut policy| T::get(&mut policy).map_or(0, |f| f)) + } + + /// Driver's `update_limit` callback. + extern "C" fn update_limits_callback(ptr: *mut bindings::cpufreq_policy) { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + T::update_limits(policy); + } + + /// Driver's `bios_limit` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn bios_limit_callback(cpu: i32, limit: *mut u32) -> kernel::ffi::c_int { + from_result(|| { + let mut policy = PolicyCpu::from_cpu(cpu as u32)?; + + // SAFETY: `limit` is guaranteed by the C code to be valid. + T::bios_limit(&mut policy, &mut (unsafe { *limit })).map(|()| 0) + }) + } + + /// Driver's `set_boost` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn set_boost_callback( + ptr: *mut bindings::cpufreq_policy, + state: i32, + ) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + T::set_boost(policy, state).map(|()| 0) + }) + } + + /// Driver's `register_em` callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn register_em_callback(ptr: *mut bindings::cpufreq_policy) { + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the + // lifetime of `policy`. + let policy = unsafe { Policy::from_raw_mut(ptr) }; + T::register_em(policy); + } +} + +impl Drop for Registration { + /// Unregisters with the cpufreq core. + fn drop(&mut self) { + // SAFETY: `self.0` is guaranteed to be valid for the lifetime of `Registration`. + unsafe { bindings::cpufreq_unregister_driver(self.0.get_mut()) }; + } +} From 14f47156cf390606eb719da9ad1058f87af0a291 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 7 Jan 2025 12:53:32 +0530 Subject: [PATCH 14/21] rust: opp: Extend OPP abstractions with cpufreq support Extend the OPP abstractions to include support for interacting with the cpufreq core, including the ability to retrieve frequency tables from OPP table. Signed-off-by: Viresh Kumar --- rust/kernel/opp.rs | 70 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) diff --git a/rust/kernel/opp.rs b/rust/kernel/opp.rs index 5293d878cb55..212555dacd45 100644 --- a/rust/kernel/opp.rs +++ b/rust/kernel/opp.rs @@ -19,6 +19,69 @@ types::{ARef, AlwaysRefCounted, Opaque}, }; +#[cfg(CONFIG_CPU_FREQ)] +/// Frequency table implementation. +mod freq { + use super::*; + use crate::cpufreq; + use core::ops::Deref; + + /// OPP frequency table. + /// + /// A [`cpufreq::Table`] created from [`Table`]. + pub struct FreqTable { + dev: ARef, + ptr: *mut bindings::cpufreq_frequency_table, + } + + impl FreqTable { + /// Creates a new instance of [`FreqTable`] from [`Table`]. + pub(crate) fn new(table: &Table) -> Result { + let mut ptr: *mut bindings::cpufreq_frequency_table = ptr::null_mut(); + + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. + to_result(unsafe { + bindings::dev_pm_opp_init_cpufreq_table(table.dev.as_raw(), &mut ptr) + })?; + + Ok(Self { + dev: table.dev.clone(), + ptr, + }) + } + + /// Returns a reference to the underlying [`cpufreq::Table`]. + #[inline] + fn table(&self) -> &cpufreq::Table { + // SAFETY: The `ptr` is guaranteed by the C code to be valid. + unsafe { cpufreq::Table::from_raw(self.ptr) } + } + } + + impl Deref for FreqTable { + type Target = cpufreq::Table; + + #[inline] + fn deref(&self) -> &Self::Target { + self.table() + } + } + + impl Drop for FreqTable { + fn drop(&mut self) { + // SAFETY: The pointer was created via `dev_pm_opp_init_cpufreq_table`, and is only + // freed here. + unsafe { + bindings::dev_pm_opp_free_cpufreq_table(self.dev.as_raw(), &mut self.as_raw()) + }; + } + } +} + +#[cfg(CONFIG_CPU_FREQ)] +pub use freq::FreqTable; + use core::{marker::PhantomData, ptr}; use macros::vtable; @@ -753,6 +816,13 @@ pub fn adjust_voltage( }) } + /// Creates [`FreqTable`] from [`Table`]. + #[cfg(CONFIG_CPU_FREQ)] + #[inline] + pub fn cpufreq_table(&mut self) -> Result { + FreqTable::new(self) + } + /// Configures device with [`OPP`] matching the frequency value. #[inline] pub fn set_rate(&self, freq: Hertz) -> Result { From 06149d8f2216894cee86106c701d13141948f159 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 1 Feb 2024 10:36:24 +0530 Subject: [PATCH 15/21] cpufreq: Add Rust-based cpufreq-dt driver Introduce a Rust-based implementation of the cpufreq-dt driver, covering most of the functionality provided by the existing C version. Some features, such as retrieving platform data from `cpufreq-dt-platdev.c`, are still pending. The driver has been tested with QEMU, and frequency scaling works as expected. Signed-off-by: Viresh Kumar --- drivers/cpufreq/Kconfig | 12 ++ drivers/cpufreq/Makefile | 1 + drivers/cpufreq/rcpufreq_dt.rs | 226 +++++++++++++++++++++++++++++++++ 3 files changed, 239 insertions(+) create mode 100644 drivers/cpufreq/rcpufreq_dt.rs diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig index d64b07ec48e5..78702a08364f 100644 --- a/drivers/cpufreq/Kconfig +++ b/drivers/cpufreq/Kconfig @@ -217,6 +217,18 @@ config CPUFREQ_DT If in doubt, say N. +config CPUFREQ_DT_RUST + tristate "Rust based Generic DT based cpufreq driver" + depends on HAVE_CLK && OF && RUST + select CPUFREQ_DT_PLATDEV + select PM_OPP + help + This adds a Rust based generic DT based cpufreq driver for frequency + management. It supports both uniprocessor (UP) and symmetric + multiprocessor (SMP) systems. + + If in doubt, say N. + config CPUFREQ_VIRT tristate "Virtual cpufreq driver" depends on GENERIC_ARCH_TOPOLOGY diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index 22ab45209f9b..d38526b8e063 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -15,6 +15,7 @@ obj-$(CONFIG_CPU_FREQ_GOV_COMMON) += cpufreq_governor.o obj-$(CONFIG_CPU_FREQ_GOV_ATTR_SET) += cpufreq_governor_attr_set.o obj-$(CONFIG_CPUFREQ_DT) += cpufreq-dt.o +obj-$(CONFIG_CPUFREQ_DT_RUST) += rcpufreq_dt.o obj-$(CONFIG_CPUFREQ_DT_PLATDEV) += cpufreq-dt-platdev.o obj-$(CONFIG_CPUFREQ_VIRT) += virtual-cpufreq.o diff --git a/drivers/cpufreq/rcpufreq_dt.rs b/drivers/cpufreq/rcpufreq_dt.rs new file mode 100644 index 000000000000..94ed81644fe1 --- /dev/null +++ b/drivers/cpufreq/rcpufreq_dt.rs @@ -0,0 +1,226 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Rust based implementation of the cpufreq-dt driver. + +use kernel::{ + c_str, + clk::Clk, + cpu, cpufreq, + cpumask::CpumaskVar, + device::{Core, Device}, + error::code::*, + fmt, + macros::vtable, + module_platform_driver, of, opp, platform, + prelude::*, + str::CString, + sync::Arc, +}; + +/// Finds exact supply name from the OF node. +fn find_supply_name_exact(dev: &Device, name: &str) -> Option { + let prop_name = CString::try_from_fmt(fmt!("{}-supply", name)).ok()?; + dev.property_present(&prop_name) + .then(|| CString::try_from_fmt(fmt!("{name}")).ok()) + .flatten() +} + +/// Finds supply name for the CPU from DT. +fn find_supply_names(dev: &Device, cpu: u32) -> Option> { + // Try "cpu0" for older DTs, fallback to "cpu". + let name = (cpu == 0) + .then(|| find_supply_name_exact(dev, "cpu0")) + .flatten() + .or_else(|| find_supply_name_exact(dev, "cpu"))?; + + let mut list = KVec::with_capacity(1, GFP_KERNEL).ok()?; + list.push(name, GFP_KERNEL).ok()?; + + Some(list) +} + +/// Represents the cpufreq dt device. +struct CPUFreqDTDevice { + opp_table: opp::Table, + freq_table: opp::FreqTable, + _mask: CpumaskVar, + _token: Option, + _clk: Clk, +} + +#[derive(Default)] +struct CPUFreqDTDriver; + +#[vtable] +impl opp::ConfigOps for CPUFreqDTDriver {} + +#[vtable] +impl cpufreq::Driver for CPUFreqDTDriver { + const NAME: &'static CStr = c_str!("cpufreq-dt"); + const FLAGS: u16 = cpufreq::flags::NEED_INITIAL_FREQ_CHECK | cpufreq::flags::IS_COOLING_DEV; + const BOOST_ENABLED: bool = true; + + type PData = Arc; + + fn init(policy: &mut cpufreq::Policy) -> Result { + let cpu = policy.cpu(); + // SAFETY: The CPU device is only used during init; it won't get hot-unplugged. The cpufreq + // core registers with CPU notifiers and the cpufreq core/driver won't use the CPU device, + // once the CPU is hot-unplugged. + let dev = unsafe { cpu::from_cpu(cpu)? }; + let mut mask = CpumaskVar::new_zero(GFP_KERNEL)?; + + mask.set(cpu); + + let token = find_supply_names(dev, cpu) + .map(|names| { + opp::Config::::new() + .set_regulator_names(names)? + .set(dev) + }) + .transpose()?; + + // Get OPP-sharing information from "operating-points-v2" bindings. + let fallback = match opp::Table::of_sharing_cpus(dev, &mut mask) { + Ok(()) => false, + Err(e) if e == ENOENT => { + // "operating-points-v2" not supported. If the platform hasn't + // set sharing CPUs, fallback to all CPUs share the `Policy` + // for backward compatibility. + opp::Table::sharing_cpus(dev, &mut mask).is_err() + } + Err(e) => return Err(e), + }; + + // Initialize OPP tables for all policy cpus. + // + // For platforms not using "operating-points-v2" bindings, we do this + // before updating policy cpus. Otherwise, we will end up creating + // duplicate OPPs for the CPUs. + // + // OPPs might be populated at runtime, don't fail for error here unless + // it is -EPROBE_DEFER. + let mut opp_table = match opp::Table::from_of_cpumask(dev, &mut mask) { + Ok(table) => table, + Err(e) => { + if e == EPROBE_DEFER { + return Err(e); + } + + // The table is added dynamically ? + opp::Table::from_dev(dev)? + } + }; + + // The OPP table must be initialized, statically or dynamically, by this point. + opp_table.opp_count()?; + + // Set sharing cpus for fallback scenario. + if fallback { + mask.setall(); + opp_table.set_sharing_cpus(&mut mask)?; + } + + let mut transition_latency = opp_table.max_transition_latency_ns() as u32; + if transition_latency == 0 { + transition_latency = cpufreq::ETERNAL_LATENCY_NS; + } + + policy + .set_dvfs_possible_from_any_cpu(true) + .set_suspend_freq(opp_table.suspend_freq()) + .set_transition_latency_ns(transition_latency); + + let freq_table = opp_table.cpufreq_table()?; + // SAFETY: The `freq_table` is not dropped while it is getting used by the C code. + unsafe { policy.set_freq_table(&freq_table) }; + + // SAFETY: The returned `clk` is not dropped while it is getting used by the C code. + let clk = unsafe { policy.set_clk(dev, None)? }; + + mask.copy(policy.cpus()); + + Ok(Arc::new( + CPUFreqDTDevice { + opp_table, + freq_table, + _mask: mask, + _token: token, + _clk: clk, + }, + GFP_KERNEL, + )?) + } + + fn exit(_policy: &mut cpufreq::Policy, _data: Option) -> Result { + Ok(()) + } + + fn online(_policy: &mut cpufreq::Policy) -> Result { + // We did light-weight tear down earlier, nothing to do here. + Ok(()) + } + + fn offline(_policy: &mut cpufreq::Policy) -> Result { + // Preserve policy->data and don't free resources on light-weight + // tear down. + Ok(()) + } + + fn suspend(policy: &mut cpufreq::Policy) -> Result { + policy.generic_suspend() + } + + fn verify(data: &mut cpufreq::PolicyData) -> Result { + data.generic_verify() + } + + fn target_index(policy: &mut cpufreq::Policy, index: cpufreq::TableIndex) -> Result { + let Some(data) = policy.data::() else { + return Err(ENOENT); + }; + + let freq = data.freq_table.freq(index)?; + data.opp_table.set_rate(freq) + } + + fn get(policy: &mut cpufreq::Policy) -> Result { + policy.generic_get() + } + + fn set_boost(_policy: &mut cpufreq::Policy, _state: i32) -> Result { + Ok(()) + } + + fn register_em(policy: &mut cpufreq::Policy) { + policy.register_em_opp() + } +} + +kernel::of_device_table!( + OF_TABLE, + MODULE_OF_TABLE, + ::IdInfo, + [(of::DeviceId::new(c_str!("operating-points-v2")), ())] +); + +impl platform::Driver for CPUFreqDTDriver { + type IdInfo = (); + const OF_ID_TABLE: Option> = Some(&OF_TABLE); + + fn probe( + pdev: &platform::Device, + _id_info: Option<&Self::IdInfo>, + ) -> Result>> { + cpufreq::Registration::::new_foreign_owned(pdev.as_ref())?; + Ok(KBox::new(Self {}, GFP_KERNEL)?.into()) + } +} + +module_platform_driver! { + type: CPUFreqDTDriver, + name: "cpufreq-dt", + author: "Viresh Kumar ", + description: "Generic CPUFreq DT driver", + license: "GPL v2", +} From 6c9bb86922728c7a4cceb99f131e00dd87514f20 Mon Sep 17 00:00:00 2001 From: Mike Tipton Date: Wed, 14 May 2025 20:53:12 -0700 Subject: [PATCH 16/21] cpufreq: scmi: Skip SCMI devices that aren't used by the CPUs Currently, all SCMI devices with performance domains attempt to register a cpufreq driver, even if their performance domains aren't used to control the CPUs. The cpufreq framework only supports registering a single driver, so only the first device will succeed. And if that device isn't used for the CPUs, then cpufreq will scale the wrong domains. To avoid this, return early from scmi_cpufreq_probe() if the probing SCMI device isn't referenced by the CPU device phandles. This keeps the existing assumption that all CPUs are controlled by a single SCMI device. Signed-off-by: Mike Tipton Reviewed-by: Peng Fan Reviewed-by: Cristian Marussi Reviewed-by: Sudeep Holla Tested-by: Cristian Marussi Signed-off-by: Viresh Kumar --- drivers/cpufreq/scmi-cpufreq.c | 36 +++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c index 944e899eb1be..ef078426bfd5 100644 --- a/drivers/cpufreq/scmi-cpufreq.c +++ b/drivers/cpufreq/scmi-cpufreq.c @@ -393,6 +393,40 @@ static struct cpufreq_driver scmi_cpufreq_driver = { .set_boost = cpufreq_boost_set_sw, }; +static bool scmi_dev_used_by_cpus(struct device *scmi_dev) +{ + struct device_node *scmi_np = dev_of_node(scmi_dev); + struct device_node *cpu_np, *np; + struct device *cpu_dev; + int cpu, idx; + + if (!scmi_np) + return false; + + for_each_possible_cpu(cpu) { + cpu_dev = get_cpu_device(cpu); + if (!cpu_dev) + continue; + + cpu_np = dev_of_node(cpu_dev); + + np = of_parse_phandle(cpu_np, "clocks", 0); + of_node_put(np); + + if (np == scmi_np) + return true; + + idx = of_property_match_string(cpu_np, "power-domain-names", "perf"); + np = of_parse_phandle(cpu_np, "power-domains", idx); + of_node_put(np); + + if (np == scmi_np) + return true; + } + + return false; +} + static int scmi_cpufreq_probe(struct scmi_device *sdev) { int ret; @@ -401,7 +435,7 @@ static int scmi_cpufreq_probe(struct scmi_device *sdev) handle = sdev->handle; - if (!handle) + if (!handle || !scmi_dev_used_by_cpus(dev)) return -ENODEV; scmi_cpufreq_driver.driver_data = sdev; From 21d8a6857bc11f3fa14b19768d840cf6d1f3fccd Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Mon, 26 May 2025 11:05:03 +0530 Subject: [PATCH 17/21] rust: opp: Make the doctest example depend on CONFIG_OF The doctest example uses a function only available for CONFIG_OF and so the build with doc tests fails when it isn't enabled. error[E0599]: no function or associated item named `from_of_cpumask` found for struct `rust_doctest_kernel_alloc_kbox_rs_4::kernel::opp::Table` in the current scope Fix this by making the doctest depend on CONFIG_OF. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202505260856.ZQWHW2xT-lkp@intel.com/ Signed-off-by: Viresh Kumar Link: https://patch.msgid.link/a80bfedcb4d94531dc27d3b48062db5042078e88.1748237646.git.viresh.kumar@linaro.org Signed-off-by: Rafael J. Wysocki --- rust/kernel/opp.rs | 1 + 1 file changed, 1 insertion(+) diff --git a/rust/kernel/opp.rs b/rust/kernel/opp.rs index 212555dacd45..c2bdc11f3999 100644 --- a/rust/kernel/opp.rs +++ b/rust/kernel/opp.rs @@ -582,6 +582,7 @@ extern "C" fn config_regulators( /// use kernel::opp::Table; /// use kernel::types::ARef; /// +/// #[cfg(CONFIG_OF)] /// fn get_table(dev: &ARef, mask: &mut Cpumask, freq: Hertz) -> Result
{ /// let mut opp_table = Table::from_of_cpumask(dev, mask)?; /// From 39cdf87a97fdab067e82138ad4611b764f3eae15 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Tue, 27 May 2025 08:45:21 +0300 Subject: [PATCH 18/21] cpuidle: psci: Fix uninitialized variable in dt_idle_state_present() If the first cpu_node = of_cpu_device_node_get() fails then the cleanup.h code will try to free "state_node" but it hasn't been initialized yet. Declare the device_nodes where they are initialized to fix this. Fixes: 5836ebeb4a2b ("cpuidle: psci: Avoid initializing faux device if no DT idle states are present") Signed-off-by: Dan Carpenter Link: https://patch.msgid.link/aDVRcfU8O8sez1x7@stanley.mountain Signed-off-by: Rafael J. Wysocki --- drivers/cpuidle/cpuidle-psci.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c index 40f378c1dc9f..eef70b5259bc 100644 --- a/drivers/cpuidle/cpuidle-psci.c +++ b/drivers/cpuidle/cpuidle-psci.c @@ -440,14 +440,13 @@ static struct faux_device_ops psci_cpuidle_ops = { static bool __init dt_idle_state_present(void) { - struct device_node *cpu_node __free(device_node); - struct device_node *state_node __free(device_node); - - cpu_node = of_cpu_device_node_get(cpumask_first(cpu_possible_mask)); + struct device_node *cpu_node __free(device_node) = + of_cpu_device_node_get(cpumask_first(cpu_possible_mask)); if (!cpu_node) return false; - state_node = of_get_cpu_state_node(cpu_node, 0); + struct device_node *state_node __free(device_node) = + of_get_cpu_state_node(cpu_node, 0); if (!state_node) return false; From 15bc5c00d10fb643df7939d34438d50ffa732cb2 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 27 May 2025 11:03:26 +0530 Subject: [PATCH 19/21] rust: opp: Move `cfg(CONFIG_OF)` attribute to the top of doc test Move the `#[cfg(CONFIG_OF)]` attribute to the top of the documentation test block and hide it. This applies the condition to the entire test and improves readability. Placing configuration flags like `CONFIG_OF` at the top serves as a clear indicator of the conditions under which the example is valid, effectively acting like configuration metadata for the example itself. Suggested-by: Miguel Ojeda Signed-off-by: Viresh Kumar Link: https://patch.msgid.link/9d93c783cc4419f16dd8942a4359d74bc0149203.1748323971.git.viresh.kumar@linaro.org Signed-off-by: Rafael J. Wysocki --- rust/kernel/opp.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/rust/kernel/opp.rs b/rust/kernel/opp.rs index c2bdc11f3999..a566fc3e7dcb 100644 --- a/rust/kernel/opp.rs +++ b/rust/kernel/opp.rs @@ -575,6 +575,7 @@ extern "C" fn config_regulators( /// frequency. /// /// ``` +/// # #![cfg(CONFIG_OF)] /// use kernel::clk::Hertz; /// use kernel::cpumask::Cpumask; /// use kernel::device::Device; @@ -582,7 +583,6 @@ extern "C" fn config_regulators( /// use kernel::opp::Table; /// use kernel::types::ARef; /// -/// #[cfg(CONFIG_OF)] /// fn get_table(dev: &ARef, mask: &mut Cpumask, freq: Hertz) -> Result
{ /// let mut opp_table = Table::from_of_cpumask(dev, mask)?; /// From cb6a85f38f456b086c366e346ebb67ffa70c7243 Mon Sep 17 00:00:00 2001 From: "Gautham R. Shenoy" Date: Thu, 29 May 2025 14:21:43 +0530 Subject: [PATCH 20/21] acpi-cpufreq: Fix nominal_freq units to KHz in get_max_boost_ratio() commit 083466754596 ("cpufreq: ACPI: Fix max-frequency computation") modified get_max_boost_ratio() to return the nominal_freq advertised in the _CPC object. This was for the purposes of computing the maximum frequency. The frequencies advertised in _CPC objects are in MHz. However, cpufreq expects the frequency to be in KHz. Since the nominal_freq returned by get_max_boost_ratio() was not in KHz but instead in MHz,the cpuinfo_max_frequency that was computed using this nominal_freq was incorrect and an invalid value which resulted in cpufreq reporting the P0 frequency as the cpuinfo_max_freq. Fix this by converting the nominal_freq to KHz before returning the same from get_max_boost_ratio(). Reported-by: Manu Bretelle Closes: https://lore.kernel.org/lkml/aDaB63tDvbdcV0cg@HQ-GR2X1W2P57/ Fixes: 083466754596 ("cpufreq: ACPI: Fix max-frequency computation") Signed-off-by: Gautham R. Shenoy Cc: 6.14+ # 6.14+ Link: https://patch.msgid.link/20250529085143.709-1-gautham.shenoy@amd.com Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/acpi-cpufreq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c index d26b610e4f24..76768fe213a9 100644 --- a/drivers/cpufreq/acpi-cpufreq.c +++ b/drivers/cpufreq/acpi-cpufreq.c @@ -660,7 +660,7 @@ static u64 get_max_boost_ratio(unsigned int cpu, u64 *nominal_freq) nominal_perf = perf_caps.nominal_perf; if (nominal_freq) - *nominal_freq = perf_caps.nominal_freq; + *nominal_freq = perf_caps.nominal_freq * 1000; if (!highest_perf || !nominal_perf) { pr_debug("CPU%d: highest or nominal performance missing\n", cpu); From 70523f335734b0b42f97647556d331edf684c7dc Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 29 May 2025 15:40:43 +0200 Subject: [PATCH 21/21] Revert "x86/smp: Eliminate mwait_play_dead_cpuid_hint()" Revert commit 96040f7273e2 ("x86/smp: Eliminate mwait_play_dead_cpuid_hint()") because it introduced a significant power regression on systems that start with "nosmt" in the kernel command line. Namely, on such systems, SMT siblings permanently go offline early, when cpuidle has not been initialized yet, so after the above commit, hlt_play_dead() is called for them. Later on, when the processor attempts to enter a deep package C-state, including PC10 which is requisite for reaching minimum power in suspend-to-idle, it is not able to do that because of the SMT siblings staying in C1 (which they have been put into by HLT). As a result, the idle power (including power in suspend-to-idle) rises quite dramatically on those systems with all of the possible consequences, which (needless to say) may not be expected by their users. This issue is hard to debug and potentially dangerous, so it needs to be addressed as soon as possible in a way that will work for 6.15.y, hence the revert. Of course, after this revert, the issue that commit 96040f7273e2 attempted to address will be back and it will need to be fixed again later. Fixes: 96040f7273e2 ("x86/smp: Eliminate mwait_play_dead_cpuid_hint()") Reported-by: Todd Brandt Tested-by: Todd Brandt Cc: 6.15+ # 6.15+ Signed-off-by: Rafael J. Wysocki Acked-by: Dave Hansen Link: https://patch.msgid.link/12674167.O9o76ZdvQC@rjwysocki.net --- arch/x86/kernel/smpboot.c | 54 ++++++++++++++++++++++++++++++++++----- 1 file changed, 47 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index d6cf1e23c2a3..96355ab9aed9 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1238,10 +1238,6 @@ void play_dead_common(void) local_irq_disable(); } -/* - * We need to flush the caches before going to sleep, lest we have - * dirty data in our caches when we come back up. - */ void __noreturn mwait_play_dead(unsigned int eax_hint) { struct mwait_cpu_dead *md = this_cpu_ptr(&mwait_cpu_dead); @@ -1287,6 +1283,50 @@ void __noreturn mwait_play_dead(unsigned int eax_hint) } } +/* + * We need to flush the caches before going to sleep, lest we have + * dirty data in our caches when we come back up. + */ +static inline void mwait_play_dead_cpuid_hint(void) +{ + unsigned int eax, ebx, ecx, edx; + unsigned int highest_cstate = 0; + unsigned int highest_subcstate = 0; + int i; + + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || + boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) + return; + if (!this_cpu_has(X86_FEATURE_MWAIT)) + return; + if (!this_cpu_has(X86_FEATURE_CLFLUSH)) + return; + + eax = CPUID_LEAF_MWAIT; + ecx = 0; + native_cpuid(&eax, &ebx, &ecx, &edx); + + /* + * eax will be 0 if EDX enumeration is not valid. + * Initialized below to cstate, sub_cstate value when EDX is valid. + */ + if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED)) { + eax = 0; + } else { + edx >>= MWAIT_SUBSTATE_SIZE; + for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) { + if (edx & MWAIT_SUBSTATE_MASK) { + highest_cstate = i; + highest_subcstate = edx & MWAIT_SUBSTATE_MASK; + } + } + eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) | + (highest_subcstate - 1); + } + + mwait_play_dead(eax); +} + /* * Kick all "offline" CPUs out of mwait on kexec(). See comment in * mwait_play_dead(). @@ -1337,9 +1377,9 @@ void native_play_dead(void) play_dead_common(); tboot_shutdown(TB_SHUTDOWN_WFS); - /* Below returns only on error. */ - cpuidle_play_dead(); - hlt_play_dead(); + mwait_play_dead_cpuid_hint(); + if (cpuidle_play_dead()) + hlt_play_dead(); } #else /* ... !CONFIG_HOTPLUG_CPU */