1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (c) 2015 Google, Inc
4 * Written by Simon Glass <sjg@chromium.org>
5 */
6
7#include <common.h>
8#include <command.h>
9#include <errno.h>
10#include <time.h>
11#include <linux/delay.h>
12
13static int test_get_timer(void)
14{
15	ulong base, start, next, diff;
16	int iter;
17
18	base = get_timer(0);
19	start = get_timer(0);
20	for (iter = 0; iter < 10; iter++) {
21		do {
22			next = get_timer(0);
23		} while (start == next);
24
25		if (start + 1 != next) {
26			printf("%s: iter=%d, start=%lu, next=%lu, expected a difference of 1\n",
27			       __func__, iter, start, next);
28			return -EINVAL;
29		}
30		start++;
31	}
32
33	/*
34	 * Check that get_timer(base) matches our elapsed time, allowing that
35	 * an extra millisecond may have passed.
36	 */
37	diff = get_timer(base);
38	if (diff != iter && diff != iter + 1) {
39		printf("%s: expected get_timer(base) to match elapsed time: diff=%lu, expected=%d\n",
40		       __func__, diff, iter);
41			return -EINVAL;
42	}
43
44	return 0;
45}
46
47static int test_timer_get_us(void)
48{
49	ulong prev, next, min = 1000000;
50	long delta;
51	int iter;
52
53	/* Find the minimum delta we can measure, in microseconds */
54	prev = timer_get_us();
55	for (iter = 0; iter < 100; ) {
56		next = timer_get_us();
57		if (next != prev) {
58			delta = next - prev;
59			if (delta < 0) {
60				printf("%s: timer_get_us() went backwards from %lu to %lu\n",
61				       __func__, prev, next);
62				return -EINVAL;
63			} else if (delta != 0) {
64				if (delta < min)
65					min = delta;
66				prev = next;
67				iter++;
68			}
69		}
70	}
71
72	if (min != 1) {
73		printf("%s: Minimum microsecond delta should be 1 but is %lu\n",
74		       __func__, min);
75		return -EINVAL;
76	}
77
78	return 0;
79}
80
81static int test_time_comparison(void)
82{
83	ulong start_us, end_us, delta_us;
84	long error;
85	ulong start;
86
87	start = get_timer(0);
88	start_us = timer_get_us();
89	while (get_timer(start) < 1000)
90		;
91	end_us = timer_get_us();
92	delta_us = end_us - start_us;
93	error = delta_us - 1000000;
94	printf("%s: Microsecond time for 1 second: %lu, error = %ld\n",
95	       __func__, delta_us, error);
96	if (abs(error) > 1000)
97		return -EINVAL;
98
99	return 0;
100}
101
102static int test_udelay(void)
103{
104	long error;
105	ulong start, delta;
106	int iter;
107
108	start = get_timer(0);
109	for (iter = 0; iter < 1000; iter++)
110		udelay(1000);
111	delta = get_timer(start);
112	error = delta - 1000;
113	printf("%s: Delay time for 1000 udelay(1000): %lu ms, error = %ld\n",
114	       __func__, delta, error);
115	if (abs(error) > 100)
116		return -EINVAL;
117
118	return 0;
119}
120
121int do_ut_time(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
122{
123	int ret = 0;
124
125	ret |= test_get_timer();
126	ret |= test_timer_get_us();
127	ret |= test_time_comparison();
128	ret |= test_udelay();
129
130	printf("Test %s\n", ret ? "failed" : "passed");
131
132	return ret ? CMD_RET_FAILURE : CMD_RET_SUCCESS;
133}
134