rust: hrtimer: add clocksource selection through `ClockId`

Allow selecting a clock source for timers by passing a `ClockId` variant to `HrTimer::new`.

Andreas Hindborg committed 1 year ago

Commit aa33de01 parent bfa3a412 files · +69 −2Browse files

Unified · Split

2 files

rust/kernel/time.rs +66 −0
rust/kernel/time/hrtimer.rs +3 −2

@@ -83,3 +83,69 @@ impl core::ops::Sub for Ktime { · 82 unmodified lines
83	}	83	}
84	}	84	}
85	}	85	}
		86
		87	/// An identifier for a clock. Used when specifying clock sources.
		88	///
		89	///
		90	/// Selection of the clock depends on the use case. In some cases the usage of a
		91	/// particular clock is mandatory, e.g. in network protocols, filesystems.In other
		92	/// cases the user of the clock has to decide which clock is best suited for the
		93	/// purpose. In most scenarios clock [`ClockId::Monotonic`] is the best choice as it
		94	/// provides a accurate monotonic notion of time (leap second smearing ignored).
		95	#[derive(Clone, Copy, PartialEq, Eq, Debug)]
		96	#[repr(u32)]
		97	pub enum ClockId {
		98	/// A settable system-wide clock that measures real (i.e., wall-clock) time.
		99	///
		100	/// Setting this clock requires appropriate privileges. This clock is
		101	/// affected by discontinuous jumps in the system time (e.g., if the system
		102	/// administrator manually changes the clock), and by frequency adjustments
		103	/// performed by NTP and similar applications via adjtime(3), adjtimex(2),
		104	/// clock_adjtime(2), and ntp_adjtime(3). This clock normally counts the
		105	/// number of seconds since 1970-01-01 00:00:00 Coordinated Universal Time
		106	/// (UTC) except that it ignores leap seconds; near a leap second it may be
		107	/// adjusted by leap second smearing to stay roughly in sync with UTC. Leap
		108	/// second smearing applies frequency adjustments to the clock to speed up
		109	/// or slow down the clock to account for the leap second without
		110	/// discontinuities in the clock. If leap second smearing is not applied,
		111	/// the clock will experience discontinuity around leap second adjustment.
		112	RealTime = bindings::CLOCK_REALTIME,
		113	/// A monotonically increasing clock.
		114	///
		115	/// A nonsettable system-wide clock that represents monotonic time since—as
		116	/// described by POSIX—"some unspecified point in the past". On Linux, that
		117	/// point corresponds to the number of seconds that the system has been
		118	/// running since it was booted.
		119	///
		120	/// The CLOCK_MONOTONIC clock is not affected by discontinuous jumps in the
		121	/// CLOCK_REAL (e.g., if the system administrator manually changes the
		122	/// clock), but is affected by frequency adjustments. This clock does not
		123	/// count time that the system is suspended.
		124	Monotonic = bindings::CLOCK_MONOTONIC,
		125	/// A monotonic that ticks while system is suspended.
		126	///
		127	/// A nonsettable system-wide clock that is identical to CLOCK_MONOTONIC,
		128	/// except that it also includes any time that the system is suspended. This
		129	/// allows applications to get a suspend-aware monotonic clock without
		130	/// having to deal with the complications of CLOCK_REALTIME, which may have
		131	/// discontinuities if the time is changed using settimeofday(2) or similar.
		132	BootTime = bindings::CLOCK_BOOTTIME,
		133	/// International Atomic Time.
		134	///
		135	/// A system-wide clock derived from wall-clock time but counting leap seconds.
		136	///
		137	/// This clock is coupled to CLOCK_REALTIME and will be set when CLOCK_REALTIME is
		138	/// set, or when the offset to CLOCK_REALTIME is changed via adjtimex(2). This
		139	/// usually happens during boot and should not happen during normal operations.
		140	/// However, if NTP or another application adjusts CLOCK_REALTIME by leap second
		141	/// smearing, this clock will not be precise during leap second smearing.
		142	///
		143	/// The acronym TAI refers to International Atomic Time.
		144	TAI = bindings::CLOCK_TAI,
		145	}
		146
		147	impl ClockId {
		148	fn into_c(self) -> bindings::clockid_t {
		149	self as bindings::clockid_t
		150	}
		151	}

rust/kernel/time/hrtimer.rs+3−2

 //! A `restart` operation on a timer in the **stopped** state is equivalent to a
 //! `start` operation.
+use super::ClockId;
 use crate::{init::PinInit, prelude::*, time::Ktime, types::Opaque};
 use core::marker::PhantomData;
 impl<T> HrTimer<T> {
     /// Return an initializer for a new timer instance.
-    pub fn new(mode: HrTimerMode) -> impl PinInit<Self>
+    pub fn new(mode: HrTimerMode, clock: ClockId) -> impl PinInit<Self>
     where
         T: HrTimerCallback,
     {
                     bindings::hrtimer_setup(
                         place,
                         Some(T::Pointer::run),
-                        bindings::CLOCK_MONOTONIC as i32,
+                        clock.into_c(),
                         mode.into_c(),
                     );
                 }

rust: hrtimer: add clocksource selection through `ClockId`

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