time.c 2.3 KB

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  1. /*
  2. * (C) Copyright 2003
  3. * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  4. *
  5. * See file CREDITS for list of people who contributed to this
  6. * project.
  7. *
  8. * This program is free software; you can redistribute it and/or
  9. * modify it under the terms of the GNU General Public License as
  10. * published by the Free Software Foundation; either version 2 of
  11. * the License, or (at your option) any later version.
  12. *
  13. * This program is distributed in the hope that it will be useful,
  14. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16. * GNU General Public License for more details.
  17. *
  18. * You should have received a copy of the GNU General Public License
  19. * along with this program; if not, write to the Free Software
  20. * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21. * MA 02111-1307 USA
  22. */
  23. #include <common.h>
  24. #include <asm/mipsregs.h>
  25. static unsigned long timestamp;
  26. /* how many counter cycles in a jiffy */
  27. #define CYCLES_PER_JIFFY (CONFIG_SYS_MIPS_TIMER_FREQ + CONFIG_SYS_HZ / 2) / CONFIG_SYS_HZ
  28. /*
  29. * timer without interrupts
  30. */
  31. int timer_init(void)
  32. {
  33. /* Set up the timer for the first expiration. */
  34. timestamp = 0;
  35. write_c0_compare(read_c0_count() + CYCLES_PER_JIFFY);
  36. return 0;
  37. }
  38. void reset_timer(void)
  39. {
  40. timestamp = 0;
  41. write_c0_compare(read_c0_count() + CYCLES_PER_JIFFY);
  42. }
  43. ulong get_timer(ulong base)
  44. {
  45. unsigned int count;
  46. unsigned int expirelo = read_c0_compare();
  47. /* Check to see if we have missed any timestamps. */
  48. count = read_c0_count();
  49. while ((count - expirelo) < 0x7fffffff) {
  50. expirelo += CYCLES_PER_JIFFY;
  51. timestamp++;
  52. }
  53. write_c0_compare(expirelo);
  54. return (timestamp - base);
  55. }
  56. void set_timer(ulong t)
  57. {
  58. timestamp = t;
  59. write_c0_compare(read_c0_count() + CYCLES_PER_JIFFY);
  60. }
  61. void __udelay(unsigned long usec)
  62. {
  63. unsigned int tmo;
  64. tmo = read_c0_count() + (usec * (CONFIG_SYS_MIPS_TIMER_FREQ / 1000000));
  65. while ((tmo - read_c0_count()) < 0x7fffffff)
  66. /*NOP*/;
  67. }
  68. /*
  69. * This function is derived from PowerPC code (read timebase as long long).
  70. * On MIPS it just returns the timer value.
  71. */
  72. unsigned long long get_ticks(void)
  73. {
  74. return get_timer(0);
  75. }
  76. /*
  77. * This function is derived from PowerPC code (timebase clock frequency).
  78. * On MIPS it returns the number of timer ticks per second.
  79. */
  80. ulong get_tbclk(void)
  81. {
  82. return CONFIG_SYS_HZ;
  83. }