syscounter.c 2.4 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Copyright (C) 2015 Freescale Semiconductor, Inc.
  4. *
  5. * The file use ls102xa/timer.c as a reference.
  6. */
  7. #include <common.h>
  8. #include <init.h>
  9. #include <time.h>
  10. #include <asm/io.h>
  11. #include <div64.h>
  12. #include <asm/arch/imx-regs.h>
  13. #include <asm/arch/sys_proto.h>
  14. #include <asm/mach-imx/syscounter.h>
  15. #include <linux/delay.h>
  16. DECLARE_GLOBAL_DATA_PTR;
  17. /*
  18. * This function is intended for SHORT delays only.
  19. * It will overflow at around 10 seconds @ 400MHz,
  20. * or 20 seconds @ 200MHz.
  21. */
  22. unsigned long usec2ticks(unsigned long usec)
  23. {
  24. ulong ticks;
  25. if (usec < 1000)
  26. ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000;
  27. else
  28. ticks = ((usec / 10) * (get_tbclk() / 100000));
  29. return ticks;
  30. }
  31. static inline unsigned long long tick_to_time(unsigned long long tick)
  32. {
  33. unsigned long freq;
  34. asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (freq));
  35. tick *= CONFIG_SYS_HZ;
  36. do_div(tick, freq);
  37. return tick;
  38. }
  39. static inline unsigned long long us_to_tick(unsigned long long usec)
  40. {
  41. unsigned long freq;
  42. asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (freq));
  43. usec = usec * freq + 999999;
  44. do_div(usec, 1000000);
  45. return usec;
  46. }
  47. #ifndef CONFIG_SKIP_LOWLEVEL_INIT
  48. int timer_init(void)
  49. {
  50. struct sctr_regs *sctr = (struct sctr_regs *)SCTR_BASE_ADDR;
  51. unsigned long val, freq;
  52. freq = CONFIG_SC_TIMER_CLK;
  53. asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq));
  54. writel(freq, &sctr->cntfid0);
  55. /* Enable system counter */
  56. val = readl(&sctr->cntcr);
  57. val &= ~(SC_CNTCR_FREQ0 | SC_CNTCR_FREQ1);
  58. val |= SC_CNTCR_FREQ0 | SC_CNTCR_ENABLE | SC_CNTCR_HDBG;
  59. writel(val, &sctr->cntcr);
  60. gd->arch.tbl = 0;
  61. gd->arch.tbu = 0;
  62. return 0;
  63. }
  64. #endif
  65. unsigned long long get_ticks(void)
  66. {
  67. unsigned long long now;
  68. asm volatile("mrrc p15, 0, %Q0, %R0, c14" : "=r" (now));
  69. gd->arch.tbl = (unsigned long)(now & 0xffffffff);
  70. gd->arch.tbu = (unsigned long)(now >> 32);
  71. return now;
  72. }
  73. ulong get_timer(ulong base)
  74. {
  75. return tick_to_time(get_ticks()) - base;
  76. }
  77. void __udelay(unsigned long usec)
  78. {
  79. unsigned long long tmp;
  80. ulong tmo;
  81. tmo = us_to_tick(usec);
  82. tmp = get_ticks() + tmo; /* get current timestamp */
  83. while (get_ticks() < tmp) /* loop till event */
  84. /*NOP*/;
  85. }
  86. /*
  87. * This function is derived from PowerPC code (timebase clock frequency).
  88. * On ARM it returns the number of timer ticks per second.
  89. */
  90. ulong get_tbclk(void)
  91. {
  92. unsigned long freq;
  93. asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (freq));
  94. return freq;
  95. }