timer.c 4.3 KB

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  1. /*
  2. * (C) Copyright 2004
  3. * Texas Instruments
  4. * Richard Woodruff <r-woodruff2@ti.com>
  5. *
  6. * (C) Copyright 2002
  7. * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  8. * Marius Groeger <mgroeger@sysgo.de>
  9. * Alex Zuepke <azu@sysgo.de>
  10. *
  11. * (C) Copyright 2002
  12. * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
  13. *
  14. * See file CREDITS for list of people who contributed to this
  15. * project.
  16. *
  17. * This program is free software; you can redistribute it and/or
  18. * modify it under the terms of the GNU General Public License as
  19. * published by the Free Software Foundation; either version 2 of
  20. * the License, or (at your option) any later version.
  21. *
  22. * This program is distributed in the hope that it will be useful,
  23. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  25. * GNU General Public License for more details.
  26. *
  27. * You should have received a copy of the GNU General Public License
  28. * along with this program; if not, write to the Free Software
  29. * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  30. * MA 02111-1307 USA
  31. */
  32. #include <common.h>
  33. #include <asm/arch/bits.h>
  34. #include <asm/arch/omap2420.h>
  35. #define TIMER_LOAD_VAL 0
  36. /* macro to read the 32 bit timer */
  37. #define READ_TIMER (*((volatile ulong *)(CONFIG_SYS_TIMERBASE+TCRR)))
  38. DECLARE_GLOBAL_DATA_PTR;
  39. static void reset_timer_masked (void)
  40. {
  41. /* reset time */
  42. gd->lastinc = READ_TIMER; /* capture current incrementer value time */
  43. gd->tbl = 0; /* start "advancing" time stamp from 0 */
  44. }
  45. int timer_init (void)
  46. {
  47. int32_t val;
  48. /* Start the counter ticking up */
  49. *((int32_t *) (CONFIG_SYS_TIMERBASE + TLDR)) = TIMER_LOAD_VAL; /* reload value on overflow*/
  50. val = (CONFIG_SYS_PTV << 2) | BIT5 | BIT1 | BIT0; /* mask to enable timer*/
  51. *((int32_t *) (CONFIG_SYS_TIMERBASE + TCLR)) = val; /* start timer */
  52. reset_timer_masked(); /* init the timestamp and lastinc value */
  53. return(0);
  54. }
  55. /*
  56. * timer without interrupts
  57. */
  58. ulong get_timer (ulong base)
  59. {
  60. return get_timer_masked () - base;
  61. }
  62. /* delay x useconds AND preserve advance timestamp value */
  63. void __udelay (unsigned long usec)
  64. {
  65. ulong tmo, tmp;
  66. if (usec >= 1000) { /* if "big" number, spread normalization to seconds */
  67. tmo = usec / 1000; /* start to normalize for usec to ticks per sec */
  68. tmo *= CONFIG_SYS_HZ; /* find number of "ticks" to wait to achieve target */
  69. tmo /= 1000; /* finish normalize. */
  70. } else { /* else small number, don't kill it prior to HZ multiply */
  71. tmo = usec * CONFIG_SYS_HZ;
  72. tmo /= (1000*1000);
  73. }
  74. tmp = get_timer (0); /* get current timestamp */
  75. if ( (tmo + tmp + 1) < tmp ) /* if setting this forward will roll time stamp */
  76. reset_timer_masked (); /* reset "advancing" timestamp to 0, set lastinc value */
  77. else
  78. tmo += tmp; /* else, set advancing stamp wake up time */
  79. while (get_timer_masked () < tmo)/* loop till event */
  80. /*NOP*/;
  81. }
  82. ulong get_timer_masked (void)
  83. {
  84. ulong now = READ_TIMER; /* current tick value */
  85. if (now >= gd->lastinc) /* normal mode (non roll) */
  86. gd->tbl += (now - gd->lastinc); /* move stamp fordward with absoulte diff ticks */
  87. else /* we have rollover of incrementer */
  88. gd->tbl += (0xFFFFFFFF - gd->lastinc) + now;
  89. gd->lastinc = now;
  90. return gd->tbl;
  91. }
  92. /* waits specified delay value and resets timestamp */
  93. void udelay_masked (unsigned long usec)
  94. {
  95. ulong tmo;
  96. ulong endtime;
  97. signed long diff;
  98. if (usec >= 1000) { /* if "big" number, spread normalization to seconds */
  99. tmo = usec / 1000; /* start to normalize for usec to ticks per sec */
  100. tmo *= CONFIG_SYS_HZ; /* find number of "ticks" to wait to achieve target */
  101. tmo /= 1000; /* finish normalize. */
  102. } else { /* else small number, don't kill it prior to HZ multiply */
  103. tmo = usec * CONFIG_SYS_HZ;
  104. tmo /= (1000*1000);
  105. }
  106. endtime = get_timer_masked () + tmo;
  107. do {
  108. ulong now = get_timer_masked ();
  109. diff = endtime - now;
  110. } while (diff >= 0);
  111. }
  112. /*
  113. * This function is derived from PowerPC code (read timebase as long long).
  114. * On ARM it just returns the timer value.
  115. */
  116. unsigned long long get_ticks(void)
  117. {
  118. return get_timer(0);
  119. }
  120. /*
  121. * This function is derived from PowerPC code (timebase clock frequency).
  122. * On ARM it returns the number of timer ticks per second.
  123. */
  124. ulong get_tbclk (void)
  125. {
  126. ulong tbclk;
  127. tbclk = CONFIG_SYS_HZ;
  128. return tbclk;
  129. }