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. #include <linux/delay.h>
  24. DECLARE_GLOBAL_DATA_PTR;
  25. static struct gptimer *timer_base = (struct gptimer *)CONFIG_SYS_TIMERBASE;
  26. static ulong get_timer_masked(void);
  27. /*
  28. * Nothing really to do with interrupts, just starts up a counter.
  29. */
  30. #define TIMER_CLOCK (V_SCLK / (2 << CONFIG_SYS_PTV))
  31. #define TIMER_OVERFLOW_VAL 0xffffffff
  32. #define TIMER_LOAD_VAL 0
  33. int timer_init(void)
  34. {
  35. /* start the counter ticking up, reload value on overflow */
  36. writel(TIMER_LOAD_VAL, &timer_base->tldr);
  37. /* enable timer */
  38. writel((CONFIG_SYS_PTV << 2) | TCLR_PRE | TCLR_AR | TCLR_ST,
  39. &timer_base->tclr);
  40. return 0;
  41. }
  42. /*
  43. * timer without interrupts
  44. */
  45. ulong get_timer(ulong base)
  46. {
  47. return get_timer_masked() - base;
  48. }
  49. /* delay x useconds */
  50. void __udelay(unsigned long usec)
  51. {
  52. long tmo = usec * (TIMER_CLOCK / 1000) / 1000;
  53. unsigned long now, last = readl(&timer_base->tcrr);
  54. while (tmo > 0) {
  55. now = readl(&timer_base->tcrr);
  56. if (last > now) /* count up timer overflow */
  57. tmo -= TIMER_OVERFLOW_VAL - last + now + 1;
  58. else
  59. tmo -= now - last;
  60. last = now;
  61. }
  62. }
  63. static ulong get_timer_masked(void)
  64. {
  65. /* current tick value */
  66. ulong now = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ);
  67. if (now >= gd->arch.lastinc) { /* normal mode (non roll) */
  68. /* move stamp fordward with absoulte diff ticks */
  69. gd->arch.tbl += (now - gd->arch.lastinc);
  70. } else { /* we have rollover of incrementer */
  71. gd->arch.tbl += ((TIMER_OVERFLOW_VAL / (TIMER_CLOCK /
  72. CONFIG_SYS_HZ)) - gd->arch.lastinc) + now;
  73. }
  74. gd->arch.lastinc = now;
  75. return gd->arch.tbl;
  76. }
  77. /*
  78. * This function is derived from PowerPC code (read timebase as long long).
  79. * On ARM it just returns the timer value.
  80. */
  81. unsigned long long get_ticks(void)
  82. {
  83. return get_timer(0);
  84. }
  85. /*
  86. * This function is derived from PowerPC code (timebase clock frequency).
  87. * On ARM it returns the number of timer ticks per second.
  88. */
  89. ulong get_tbclk(void)
  90. {
  91. return CONFIG_SYS_HZ;
  92. }