timer.c 3.9 KB

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  1. /*
  2. * Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
  3. * Copyright (C) 2011-2012 Xilinx, Inc. All rights reserved.
  4. *
  5. * (C) Copyright 2008
  6. * Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
  7. *
  8. * (C) Copyright 2004
  9. * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
  10. *
  11. * (C) Copyright 2002-2004
  12. * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
  13. *
  14. * (C) Copyright 2003
  15. * Texas Instruments <www.ti.com>
  16. *
  17. * (C) Copyright 2002
  18. * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  19. * Marius Groeger <mgroeger@sysgo.de>
  20. *
  21. * (C) Copyright 2002
  22. * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  23. * Alex Zuepke <azu@sysgo.de>
  24. *
  25. * See file CREDITS for list of people who contributed to this
  26. * project.
  27. *
  28. * This program is free software; you can redistribute it and/or
  29. * modify it under the terms of the GNU General Public License as
  30. * published by the Free Software Foundation; either version 2 of
  31. * the License, or (at your option) any later version.
  32. *
  33. * This program is distributed in the hope that it will be useful,
  34. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  35. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  36. * GNU General Public License for more details.
  37. *
  38. * You should have received a copy of the GNU General Public License
  39. * along with this program; if not, write to the Free Software
  40. * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  41. * MA 02111-1307 USA
  42. */
  43. #include <common.h>
  44. #include <div64.h>
  45. #include <asm/io.h>
  46. DECLARE_GLOBAL_DATA_PTR;
  47. struct scu_timer {
  48. u32 load; /* Timer Load Register */
  49. u32 counter; /* Timer Counter Register */
  50. u32 control; /* Timer Control Register */
  51. };
  52. static struct scu_timer *timer_base =
  53. (struct scu_timer *) CONFIG_SCUTIMER_BASEADDR;
  54. #define SCUTIMER_CONTROL_PRESCALER_MASK 0x0000FF00 /* Prescaler */
  55. #define SCUTIMER_CONTROL_PRESCALER_SHIFT 8
  56. #define SCUTIMER_CONTROL_AUTO_RELOAD_MASK 0x00000002 /* Auto-reload */
  57. #define SCUTIMER_CONTROL_ENABLE_MASK 0x00000001 /* Timer enable */
  58. #define TIMER_LOAD_VAL 0xFFFFFFFF
  59. #define TIMER_PRESCALE 255
  60. #define TIMER_TICK_HZ (CONFIG_CPU_FREQ_HZ / 2 / TIMER_PRESCALE)
  61. int timer_init(void)
  62. {
  63. const u32 emask = SCUTIMER_CONTROL_AUTO_RELOAD_MASK |
  64. (TIMER_PRESCALE << SCUTIMER_CONTROL_PRESCALER_SHIFT) |
  65. SCUTIMER_CONTROL_ENABLE_MASK;
  66. /* Load the timer counter register */
  67. writel(0xFFFFFFFF, &timer_base->counter);
  68. /*
  69. * Start the A9Timer device
  70. * Enable Auto reload mode, Clear prescaler control bits
  71. * Set prescaler value, Enable the decrementer
  72. */
  73. clrsetbits_le32(&timer_base->control, SCUTIMER_CONTROL_PRESCALER_MASK,
  74. emask);
  75. /* Reset time */
  76. gd->lastinc = readl(&timer_base->counter) /
  77. (TIMER_TICK_HZ / CONFIG_SYS_HZ);
  78. gd->arch.tbl = 0;
  79. return 0;
  80. }
  81. /*
  82. * This function is derived from PowerPC code (read timebase as long long).
  83. * On ARM it just returns the timer value.
  84. */
  85. ulong get_timer_masked(void)
  86. {
  87. ulong now;
  88. now = readl(&timer_base->counter) / (TIMER_TICK_HZ / CONFIG_SYS_HZ);
  89. if (gd->lastinc >= now) {
  90. /* Normal mode */
  91. gd->arch.tbl += gd->lastinc - now;
  92. } else {
  93. /* We have an overflow ... */
  94. gd->arch.tbl += gd->lastinc + TIMER_LOAD_VAL - now;
  95. }
  96. gd->lastinc = now;
  97. return gd->arch.tbl;
  98. }
  99. void __udelay(unsigned long usec)
  100. {
  101. unsigned long long tmp;
  102. ulong tmo;
  103. tmo = usec / (1000000 / CONFIG_SYS_HZ);
  104. tmp = get_ticks() + tmo; /* Get current timestamp */
  105. while (get_ticks() < tmp) { /* Loop till event */
  106. /* NOP */;
  107. }
  108. }
  109. /* Timer without interrupts */
  110. ulong get_timer(ulong base)
  111. {
  112. return get_timer_masked() - base;
  113. }
  114. /*
  115. * This function is derived from PowerPC code (read timebase as long long).
  116. * On ARM it just returns the timer value.
  117. */
  118. unsigned long long get_ticks(void)
  119. {
  120. return get_timer(0);
  121. }
  122. /*
  123. * This function is derived from PowerPC code (timebase clock frequency).
  124. * On ARM it returns the number of timer ticks per second.
  125. */
  126. ulong get_tbclk(void)
  127. {
  128. return CONFIG_SYS_HZ;
  129. }