1 // SPDX-License-Identifier: GPL-2.0 1 // SPDX-License-Identifier: GPL-2.0
2 2
3 //! Time related primitives. 3 //! Time related primitives.
4 //! 4 //!
5 //! This module contains the kernel APIs relat 5 //! This module contains the kernel APIs related to time and timers that
6 //! have been ported or wrapped for usage by R 6 //! have been ported or wrapped for usage by Rust code in the kernel.
7 //! 7 //!
8 //! C header: [`include/linux/jiffies.h`](srct 8 //! C header: [`include/linux/jiffies.h`](srctree/include/linux/jiffies.h).
9 //! C header: [`include/linux/ktime.h`](srctre 9 //! C header: [`include/linux/ktime.h`](srctree/include/linux/ktime.h).
10 10
11 /// The number of nanoseconds per millisecond. 11 /// The number of nanoseconds per millisecond.
12 pub const NSEC_PER_MSEC: i64 = bindings::NSEC_ 12 pub const NSEC_PER_MSEC: i64 = bindings::NSEC_PER_MSEC as i64;
13 13
14 /// The time unit of Linux kernel. One jiffy e 14 /// The time unit of Linux kernel. One jiffy equals (1/HZ) second.
15 pub type Jiffies = core::ffi::c_ulong; 15 pub type Jiffies = core::ffi::c_ulong;
16 16
17 /// The millisecond time unit. 17 /// The millisecond time unit.
18 pub type Msecs = core::ffi::c_uint; 18 pub type Msecs = core::ffi::c_uint;
19 19
20 /// Converts milliseconds to jiffies. 20 /// Converts milliseconds to jiffies.
21 #[inline] 21 #[inline]
22 pub fn msecs_to_jiffies(msecs: Msecs) -> Jiffi 22 pub fn msecs_to_jiffies(msecs: Msecs) -> Jiffies {
23 // SAFETY: The `__msecs_to_jiffies` functi 23 // SAFETY: The `__msecs_to_jiffies` function is always safe to call no
24 // matter what the argument is. 24 // matter what the argument is.
25 unsafe { bindings::__msecs_to_jiffies(msec 25 unsafe { bindings::__msecs_to_jiffies(msecs) }
26 } 26 }
27 27
28 /// A Rust wrapper around a `ktime_t`. 28 /// A Rust wrapper around a `ktime_t`.
29 #[repr(transparent)] 29 #[repr(transparent)]
30 #[derive(Copy, Clone)] 30 #[derive(Copy, Clone)]
31 pub struct Ktime { 31 pub struct Ktime {
32 inner: bindings::ktime_t, 32 inner: bindings::ktime_t,
33 } 33 }
34 34
35 impl Ktime { 35 impl Ktime {
36 /// Create a `Ktime` from a raw `ktime_t`. 36 /// Create a `Ktime` from a raw `ktime_t`.
37 #[inline] 37 #[inline]
38 pub fn from_raw(inner: bindings::ktime_t) 38 pub fn from_raw(inner: bindings::ktime_t) -> Self {
39 Self { inner } 39 Self { inner }
40 } 40 }
41 41
42 /// Get the current time using `CLOCK_MONO 42 /// Get the current time using `CLOCK_MONOTONIC`.
43 #[inline] 43 #[inline]
44 pub fn ktime_get() -> Self { 44 pub fn ktime_get() -> Self {
45 // SAFETY: It is always safe to call ` 45 // SAFETY: It is always safe to call `ktime_get` outside of NMI context.
46 Self::from_raw(unsafe { bindings::ktim 46 Self::from_raw(unsafe { bindings::ktime_get() })
47 } 47 }
48 48
49 /// Divide the number of nanoseconds by a 49 /// Divide the number of nanoseconds by a compile-time constant.
50 #[inline] 50 #[inline]
51 fn divns_constant<const DIV: i64>(self) -> 51 fn divns_constant<const DIV: i64>(self) -> i64 {
52 self.to_ns() / DIV 52 self.to_ns() / DIV
53 } 53 }
54 54
55 /// Returns the number of nanoseconds. 55 /// Returns the number of nanoseconds.
56 #[inline] 56 #[inline]
57 pub fn to_ns(self) -> i64 { 57 pub fn to_ns(self) -> i64 {
58 self.inner 58 self.inner
59 } 59 }
60 60
61 /// Returns the number of milliseconds. 61 /// Returns the number of milliseconds.
62 #[inline] 62 #[inline]
63 pub fn to_ms(self) -> i64 { 63 pub fn to_ms(self) -> i64 {
64 self.divns_constant::<NSEC_PER_MSEC>() 64 self.divns_constant::<NSEC_PER_MSEC>()
65 } 65 }
66 } 66 }
67 67
68 /// Returns the number of milliseconds between 68 /// Returns the number of milliseconds between two ktimes.
69 #[inline] 69 #[inline]
70 pub fn ktime_ms_delta(later: Ktime, earlier: K 70 pub fn ktime_ms_delta(later: Ktime, earlier: Ktime) -> i64 {
71 (later - earlier).to_ms() 71 (later - earlier).to_ms()
72 } 72 }
73 73
74 impl core::ops::Sub for Ktime { 74 impl core::ops::Sub for Ktime {
75 type Output = Ktime; 75 type Output = Ktime;
76 76
77 #[inline] 77 #[inline]
78 fn sub(self, other: Ktime) -> Ktime { 78 fn sub(self, other: Ktime) -> Ktime {
79 Self { 79 Self {
80 inner: self.inner - other.inner, 80 inner: self.inner - other.inner,
81 } 81 }
82 } 82 }
83 } 83 }
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