timer.c 4.4 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. static ulong timestamp;
  39. static ulong lastinc;
  40. int timer_init (void)
  41. {
  42. int32_t val;
  43. /* Start the counter ticking up */
  44. *((int32_t *) (CONFIG_SYS_TIMERBASE + TLDR)) = TIMER_LOAD_VAL; /* reload value on overflow*/
  45. val = (CONFIG_SYS_PTV << 2) | BIT5 | BIT1 | BIT0; /* mask to enable timer*/
  46. *((int32_t *) (CONFIG_SYS_TIMERBASE + TCLR)) = val; /* start timer */
  47. reset_timer_masked(); /* init the timestamp and lastinc value */
  48. return(0);
  49. }
  50. /*
  51. * timer without interrupts
  52. */
  53. void reset_timer (void)
  54. {
  55. reset_timer_masked ();
  56. }
  57. ulong get_timer (ulong base)
  58. {
  59. return get_timer_masked () - base;
  60. }
  61. void set_timer (ulong t)
  62. {
  63. timestamp = t;
  64. }
  65. /* delay x useconds AND perserve advance timstamp value */
  66. void udelay (unsigned long usec)
  67. {
  68. ulong tmo, tmp;
  69. if (usec >= 1000) { /* if "big" number, spread normalization to seconds */
  70. tmo = usec / 1000; /* start to normalize for usec to ticks per sec */
  71. tmo *= CONFIG_SYS_HZ; /* find number of "ticks" to wait to achieve target */
  72. tmo /= 1000; /* finish normalize. */
  73. } else { /* else small number, don't kill it prior to HZ multiply */
  74. tmo = usec * CONFIG_SYS_HZ;
  75. tmo /= (1000*1000);
  76. }
  77. tmp = get_timer (0); /* get current timestamp */
  78. if ( (tmo + tmp + 1) < tmp )/* if setting this forward will roll time stamp */
  79. reset_timer_masked (); /* reset "advancing" timestamp to 0, set lastinc value */
  80. else
  81. tmo += tmp; /* else, set advancing stamp wake up time */
  82. while (get_timer_masked () < tmo)/* loop till event */
  83. /*NOP*/;
  84. }
  85. void reset_timer_masked (void)
  86. {
  87. /* reset time */
  88. lastinc = READ_TIMER; /* capture current incrementer value time */
  89. timestamp = 0; /* start "advancing" time stamp from 0 */
  90. }
  91. ulong get_timer_masked (void)
  92. {
  93. ulong now = READ_TIMER; /* current tick value */
  94. if (now >= lastinc) /* normal mode (non roll) */
  95. timestamp += (now - lastinc); /* move stamp fordward with absoulte diff ticks */
  96. else /* we have rollover of incrementer */
  97. timestamp += (0xFFFFFFFF - lastinc) + now;
  98. lastinc = now;
  99. return timestamp;
  100. }
  101. /* waits specified delay value and resets timestamp */
  102. void udelay_masked (unsigned long usec)
  103. {
  104. ulong tmo;
  105. ulong endtime;
  106. signed long diff;
  107. if (usec >= 1000) { /* if "big" number, spread normalization to seconds */
  108. tmo = usec / 1000; /* start to normalize for usec to ticks per sec */
  109. tmo *= CONFIG_SYS_HZ; /* find number of "ticks" to wait to achieve target */
  110. tmo /= 1000; /* finish normalize. */
  111. } else { /* else small number, don't kill it prior to HZ multiply */
  112. tmo = usec * CONFIG_SYS_HZ;
  113. tmo /= (1000*1000);
  114. }
  115. endtime = get_timer_masked () + tmo;
  116. do {
  117. ulong now = get_timer_masked ();
  118. diff = endtime - now;
  119. } while (diff >= 0);
  120. }
  121. /*
  122. * This function is derived from PowerPC code (read timebase as long long).
  123. * On ARM it just returns the timer value.
  124. */
  125. unsigned long long get_ticks(void)
  126. {
  127. return get_timer(0);
  128. }
  129. /*
  130. * This function is derived from PowerPC code (timebase clock frequency).
  131. * On ARM it returns the number of timer ticks per second.
  132. */
  133. ulong get_tbclk (void)
  134. {
  135. ulong tbclk;
  136. tbclk = CONFIG_SYS_HZ;
  137. return tbclk;
  138. }