aboutsummaryrefslogtreecommitdiff
path: root/core/timebase.c
blob: fb46bcf4c30a7b6cf3fdfd4b31be1a3d1f71db19 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
/* Copyright 2013-2014 IBM Corp.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * 	http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <timebase.h>
#include <opal.h>
#include <cpu.h>

void time_wait(unsigned long duration)
{
	unsigned long end = mftb() + duration;

	while(tb_compare(mftb(), end) != TB_AAFTERB) {
		opal_run_pollers();
		cpu_relax();
        }

}

void time_wait_nopoll(unsigned long duration)
{
	unsigned long end = mftb() + duration;

	while(tb_compare(mftb(), end) != TB_AAFTERB)
		cpu_relax();
}

void time_wait_ms(unsigned long ms)
{
	time_wait(msecs_to_tb(ms));
}

void time_wait_ms_nopoll(unsigned long ms)
{
	time_wait_nopoll(msecs_to_tb(ms));
}

void time_wait_us(unsigned long us)
{
	time_wait(usecs_to_tb(us));
}

void time_wait_us_nopoll(unsigned long us)
{
	time_wait_nopoll(usecs_to_tb(us));
}

unsigned long timespec_to_tb(const struct timespec *ts)
{
	unsigned long ns;

	/* First convert to ns */
	ns = ts->tv_sec * 1000000000ul;
	ns += ts->tv_nsec;

	/*
	 * This is a very rough approximation, it works provided
	 * we never try to pass too long delays here and the TB
	 * frequency isn't significantly lower than 512Mhz.
	 *
	 * We could improve the precision by shifting less bits
	 * at the expense of capacity or do 128 bit math which
	 * I'm not eager to do :-)
	 */
	return (ns * (tb_hz >> 24)) / (1000000000ul >> 24);
}

int nanosleep(const struct timespec *req, struct timespec *rem)
{
	time_wait(timespec_to_tb(req));

	if (rem) {
		rem->tv_sec = 0;
		rem->tv_nsec = 0;
	}
	return 0;
}