test/time_ut.c

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