time_ut.c 2.7 KB

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