timer.c 2.4 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * (C) Copyright 2008
  4. * Texas Instruments
  5. *
  6. * Richard Woodruff <r-woodruff2@ti.com>
  7. * Syed Moahmmed Khasim <khasim@ti.com>
  8. *
  9. * (C) Copyright 2002
  10. * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  11. * Marius Groeger <mgroeger@sysgo.de>
  12. * Alex Zuepke <azu@sysgo.de>
  13. *
  14. * (C) Copyright 2002
  15. * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
  16. */
  17. #include <common.h>
  18. #include <init.h>
  19. #include <time.h>
  20. #include <asm/io.h>
  21. #include <asm/arch/cpu.h>
  22. #include <asm/arch/clock.h>
  23. DECLARE_GLOBAL_DATA_PTR;
  24. static struct gptimer *timer_base = (struct gptimer *)CONFIG_SYS_TIMERBASE;
  25. static ulong get_timer_masked(void);
  26. /*
  27. * Nothing really to do with interrupts, just starts up a counter.
  28. */
  29. #define TIMER_CLOCK (V_SCLK / (2 << CONFIG_SYS_PTV))
  30. #define TIMER_OVERFLOW_VAL 0xffffffff
  31. #define TIMER_LOAD_VAL 0
  32. int timer_init(void)
  33. {
  34. /* start the counter ticking up, reload value on overflow */
  35. writel(TIMER_LOAD_VAL, &timer_base->tldr);
  36. /* enable timer */
  37. writel((CONFIG_SYS_PTV << 2) | TCLR_PRE | TCLR_AR | TCLR_ST,
  38. &timer_base->tclr);
  39. return 0;
  40. }
  41. /*
  42. * timer without interrupts
  43. */
  44. ulong get_timer(ulong base)
  45. {
  46. return get_timer_masked() - base;
  47. }
  48. /* delay x useconds */
  49. void __udelay(unsigned long usec)
  50. {
  51. long tmo = usec * (TIMER_CLOCK / 1000) / 1000;
  52. unsigned long now, last = readl(&timer_base->tcrr);
  53. while (tmo > 0) {
  54. now = readl(&timer_base->tcrr);
  55. if (last > now) /* count up timer overflow */
  56. tmo -= TIMER_OVERFLOW_VAL - last + now + 1;
  57. else
  58. tmo -= now - last;
  59. last = now;
  60. }
  61. }
  62. static ulong get_timer_masked(void)
  63. {
  64. /* current tick value */
  65. ulong now = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ);
  66. if (now >= gd->arch.lastinc) { /* normal mode (non roll) */
  67. /* move stamp fordward with absoulte diff ticks */
  68. gd->arch.tbl += (now - gd->arch.lastinc);
  69. } else { /* we have rollover of incrementer */
  70. gd->arch.tbl += ((TIMER_OVERFLOW_VAL / (TIMER_CLOCK /
  71. CONFIG_SYS_HZ)) - gd->arch.lastinc) + now;
  72. }
  73. gd->arch.lastinc = now;
  74. return gd->arch.tbl;
  75. }
  76. /*
  77. * This function is derived from PowerPC code (read timebase as long long).
  78. * On ARM it just returns the timer value.
  79. */
  80. unsigned long long get_ticks(void)
  81. {
  82. return get_timer(0);
  83. }
  84. /*
  85. * This function is derived from PowerPC code (timebase clock frequency).
  86. * On ARM it returns the number of timer ticks per second.
  87. */
  88. ulong get_tbclk(void)
  89. {
  90. return CONFIG_SYS_HZ;
  91. }