test/time_ut.c

   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
  13 static 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
  47 static 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
  81 static 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
 102 static 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
 121 int 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 }