diff options
Diffstat (limited to 'rust/kernel')
| -rw-r--r-- | rust/kernel/time.rs | 147 | ||||
| -rw-r--r-- | rust/kernel/time/hrtimer.rs | 6 |
2 files changed, 84 insertions, 69 deletions
diff --git a/rust/kernel/time.rs b/rust/kernel/time.rs index b0a8f3c0ba49..1d2600288ed1 100644 --- a/rust/kernel/time.rs +++ b/rust/kernel/time.rs @@ -49,6 +49,87 @@ pub fn msecs_to_jiffies(msecs: Msecs) -> Jiffies { unsafe { bindings::__msecs_to_jiffies(msecs) } } +/// Trait for clock sources. +/// +/// Selection of the clock source depends on the use case. In some cases the usage of a +/// particular clock is mandatory, e.g. in network protocols, filesystems. In other +/// cases the user of the clock has to decide which clock is best suited for the +/// purpose. In most scenarios clock [`Monotonic`] is the best choice as it +/// provides a accurate monotonic notion of time (leap second smearing ignored). +pub trait ClockSource { + /// The kernel clock ID associated with this clock source. + /// + /// This constant corresponds to the C side `clockid_t` value. + const ID: bindings::clockid_t; +} + +/// A monotonically increasing clock. +/// +/// A nonsettable system-wide clock that represents monotonic time since as +/// described by POSIX, "some unspecified point in the past". On Linux, that +/// point corresponds to the number of seconds that the system has been +/// running since it was booted. +/// +/// The CLOCK_MONOTONIC clock is not affected by discontinuous jumps in the +/// CLOCK_REAL (e.g., if the system administrator manually changes the +/// clock), but is affected by frequency adjustments. This clock does not +/// count time that the system is suspended. +pub struct Monotonic; + +impl ClockSource for Monotonic { + const ID: bindings::clockid_t = bindings::CLOCK_MONOTONIC as bindings::clockid_t; +} + +/// A settable system-wide clock that measures real (i.e., wall-clock) time. +/// +/// Setting this clock requires appropriate privileges. This clock is +/// affected by discontinuous jumps in the system time (e.g., if the system +/// administrator manually changes the clock), and by frequency adjustments +/// performed by NTP and similar applications via adjtime(3), adjtimex(2), +/// clock_adjtime(2), and ntp_adjtime(3). This clock normally counts the +/// number of seconds since 1970-01-01 00:00:00 Coordinated Universal Time +/// (UTC) except that it ignores leap seconds; near a leap second it may be +/// adjusted by leap second smearing to stay roughly in sync with UTC. Leap +/// second smearing applies frequency adjustments to the clock to speed up +/// or slow down the clock to account for the leap second without +/// discontinuities in the clock. If leap second smearing is not applied, +/// the clock will experience discontinuity around leap second adjustment. +pub struct RealTime; + +impl ClockSource for RealTime { + const ID: bindings::clockid_t = bindings::CLOCK_REALTIME as bindings::clockid_t; +} + +/// A monotonic that ticks while system is suspended. +/// +/// A nonsettable system-wide clock that is identical to CLOCK_MONOTONIC, +/// except that it also includes any time that the system is suspended. This +/// allows applications to get a suspend-aware monotonic clock without +/// having to deal with the complications of CLOCK_REALTIME, which may have +/// discontinuities if the time is changed using settimeofday(2) or similar. +pub struct BootTime; + +impl ClockSource for BootTime { + const ID: bindings::clockid_t = bindings::CLOCK_BOOTTIME as bindings::clockid_t; +} + +/// International Atomic Time. +/// +/// A system-wide clock derived from wall-clock time but counting leap seconds. +/// +/// This clock is coupled to CLOCK_REALTIME and will be set when CLOCK_REALTIME is +/// set, or when the offset to CLOCK_REALTIME is changed via adjtimex(2). This +/// usually happens during boot and **should** not happen during normal operations. +/// However, if NTP or another application adjusts CLOCK_REALTIME by leap second +/// smearing, this clock will not be precise during leap second smearing. +/// +/// The acronym TAI refers to International Atomic Time. +pub struct Tai; + +impl ClockSource for Tai { + const ID: bindings::clockid_t = bindings::CLOCK_TAI as bindings::clockid_t; +} + /// A specific point in time. /// /// # Invariants @@ -91,72 +172,6 @@ impl core::ops::Sub for Instant { } } -/// An identifier for a clock. Used when specifying clock sources. -/// -/// -/// Selection of the clock depends on the use case. In some cases the usage of a -/// particular clock is mandatory, e.g. in network protocols, filesystems.In other -/// cases the user of the clock has to decide which clock is best suited for the -/// purpose. In most scenarios clock [`ClockId::Monotonic`] is the best choice as it -/// provides a accurate monotonic notion of time (leap second smearing ignored). -#[derive(Clone, Copy, PartialEq, Eq, Debug)] -#[repr(u32)] -pub enum ClockId { - /// A settable system-wide clock that measures real (i.e., wall-clock) time. - /// - /// Setting this clock requires appropriate privileges. This clock is - /// affected by discontinuous jumps in the system time (e.g., if the system - /// administrator manually changes the clock), and by frequency adjustments - /// performed by NTP and similar applications via adjtime(3), adjtimex(2), - /// clock_adjtime(2), and ntp_adjtime(3). This clock normally counts the - /// number of seconds since 1970-01-01 00:00:00 Coordinated Universal Time - /// (UTC) except that it ignores leap seconds; near a leap second it may be - /// adjusted by leap second smearing to stay roughly in sync with UTC. Leap - /// second smearing applies frequency adjustments to the clock to speed up - /// or slow down the clock to account for the leap second without - /// discontinuities in the clock. If leap second smearing is not applied, - /// the clock will experience discontinuity around leap second adjustment. - RealTime = bindings::CLOCK_REALTIME, - /// A monotonically increasing clock. - /// - /// A nonsettable system-wide clock that represents monotonic time since—as - /// described by POSIX—"some unspecified point in the past". On Linux, that - /// point corresponds to the number of seconds that the system has been - /// running since it was booted. - /// - /// The CLOCK_MONOTONIC clock is not affected by discontinuous jumps in the - /// CLOCK_REAL (e.g., if the system administrator manually changes the - /// clock), but is affected by frequency adjustments. This clock does not - /// count time that the system is suspended. - Monotonic = bindings::CLOCK_MONOTONIC, - /// A monotonic that ticks while system is suspended. - /// - /// A nonsettable system-wide clock that is identical to CLOCK_MONOTONIC, - /// except that it also includes any time that the system is suspended. This - /// allows applications to get a suspend-aware monotonic clock without - /// having to deal with the complications of CLOCK_REALTIME, which may have - /// discontinuities if the time is changed using settimeofday(2) or similar. - BootTime = bindings::CLOCK_BOOTTIME, - /// International Atomic Time. - /// - /// A system-wide clock derived from wall-clock time but counting leap seconds. - /// - /// This clock is coupled to CLOCK_REALTIME and will be set when CLOCK_REALTIME is - /// set, or when the offset to CLOCK_REALTIME is changed via adjtimex(2). This - /// usually happens during boot and **should** not happen during normal operations. - /// However, if NTP or another application adjusts CLOCK_REALTIME by leap second - /// smearing, this clock will not be precise during leap second smearing. - /// - /// The acronym TAI refers to International Atomic Time. - TAI = bindings::CLOCK_TAI, -} - -impl ClockId { - fn into_c(self) -> bindings::clockid_t { - self as bindings::clockid_t - } -} - /// A span of time. /// /// This struct represents a span of time, with its value stored as nanoseconds. diff --git a/rust/kernel/time/hrtimer.rs b/rust/kernel/time/hrtimer.rs index 36e1290cd079..20b87a4d65ae 100644 --- a/rust/kernel/time/hrtimer.rs +++ b/rust/kernel/time/hrtimer.rs @@ -67,7 +67,7 @@ //! A `restart` operation on a timer in the **stopped** state is equivalent to a //! `start` operation. -use super::ClockId; +use super::ClockSource; use crate::{prelude::*, types::Opaque}; use core::marker::PhantomData; use pin_init::PinInit; @@ -112,7 +112,7 @@ unsafe impl<T> Sync for HrTimer<T> {} impl<T> HrTimer<T> { /// Return an initializer for a new timer instance. - pub fn new(mode: HrTimerMode, clock: ClockId) -> impl PinInit<Self> + pub fn new<U: ClockSource>(mode: HrTimerMode) -> impl PinInit<Self> where T: HrTimerCallback, { @@ -126,7 +126,7 @@ impl<T> HrTimer<T> { bindings::hrtimer_setup( place, Some(T::Pointer::run), - clock.into_c(), + U::ID, mode.into_c(), ); } |