xref: /DragonOS/kernel/src/time/timekeep.rs (revision fae6e9ade46a52976ad5d099643d51cc20876448)
1 #![allow(dead_code)]
2 
3 use core::intrinsics::unlikely;
4 
5 use system_error::SystemError;
6 
7 use crate::driver::rtc::interface::rtc_read_time_default;
8 
9 use super::{PosixTimeSpec, NSEC_PER_SEC};
10 
11 // 参考:https://code.dragonos.org.cn/xref/linux-3.4.99/include/linux/time.h#110
12 const KTIME_MAX: i64 = !(1u64 << 63) as i64;
13 const KTIME_SEC_MAX: i64 = KTIME_MAX / NSEC_PER_SEC as i64;
14 
15 #[allow(non_camel_case_types)]
16 pub type ktime_t = i64;
17 
18 // @brief 将ktime_t类型转换为纳秒类型
19 #[inline]
20 fn ktime_to_ns(kt: ktime_t) -> i64 {
21     return kt;
22 }
23 
24 /// @brief 从RTC获取当前时间,然后计算时间戳。
25 /// 时间戳为从UTC+0 1970-01-01 00:00到当前UTC+0时间,所经过的纳秒数。
26 /// 注意,由于当前未引入时区,因此本函数默认时区为UTC+8来计算
27 fn ktime_get_real() -> Result<ktime_t, SystemError> {
28     let rtc_time = rtc_read_time_default()?;
29     let time_spec: PosixTimeSpec = rtc_time.into();
30     let r = time_spec.tv_sec * 1_000_000_000 + time_spec.tv_nsec;
31     return Ok(r);
32 }
33 
34 /// @brief 暴露给外部使用的接口,返回一个时间戳
35 #[inline]
36 pub fn ktime_get_real_ns() -> i64 {
37     let kt: ktime_t = ktime_get_real().unwrap_or(0);
38     return ktime_to_ns(kt);
39 }
40 
41 // # 用于将两个ktime_t类型的变量相加
42 // #[inline(always)]
43 // pub(super) fn ktime_add(add1: ktime_t, add2: ktime_t) -> ktime_t {
44 //     let res = add1 + add2;
45 // }
46 
47 /// # 通过sec和nsec构造一个ktime_t
48 #[inline(always)]
49 fn ktime_set(secs: i64, nsecs: u64) -> ktime_t {
50     if unlikely(secs >= KTIME_SEC_MAX) {
51         return KTIME_MAX;
52     }
53 
54     return secs * NSEC_PER_SEC as i64 + nsecs as i64;
55 }
56 
57 /// # 将PosixTimeSpec转换成ktime_t
58 #[inline(always)]
59 pub fn timespec_to_ktime(ts: PosixTimeSpec) -> ktime_t {
60     return ktime_set(ts.tv_sec, ts.tv_nsec as u64);
61 }
62