time.c 3.5 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137
  1. /*
  2. * arch/arm/mach-pnx4008/time.c
  3. *
  4. * PNX4008 Timers
  5. *
  6. * Authors: Vitaly Wool, Dmitry Chigirev, Grigory Tolstolytkin <source@mvista.com>
  7. *
  8. * 2005 (c) MontaVista Software, Inc. This file is licensed under
  9. * the terms of the GNU General Public License version 2. This program
  10. * is licensed "as is" without any warranty of any kind, whether express
  11. * or implied.
  12. */
  13. #include <linux/kernel.h>
  14. #include <linux/init.h>
  15. #include <linux/delay.h>
  16. #include <linux/interrupt.h>
  17. #include <linux/sched.h>
  18. #include <linux/spinlock.h>
  19. #include <linux/module.h>
  20. #include <linux/kallsyms.h>
  21. #include <linux/time.h>
  22. #include <linux/timex.h>
  23. #include <linux/irq.h>
  24. #include <asm/system.h>
  25. #include <asm/hardware.h>
  26. #include <asm/io.h>
  27. #include <asm/leds.h>
  28. #include <asm/mach/time.h>
  29. #include <asm/errno.h>
  30. /*! Note: all timers are UPCOUNTING */
  31. /*!
  32. * Returns number of us since last clock interrupt. Note that interrupts
  33. * will have been disabled by do_gettimeoffset()
  34. */
  35. static unsigned long pnx4008_gettimeoffset(void)
  36. {
  37. u32 ticks_to_match =
  38. __raw_readl(HSTIM_MATCH0) - __raw_readl(HSTIM_COUNTER);
  39. u32 elapsed = LATCH - ticks_to_match;
  40. return (elapsed * (tick_nsec / 1000)) / LATCH;
  41. }
  42. /*!
  43. * IRQ handler for the timer
  44. */
  45. static irqreturn_t pnx4008_timer_interrupt(int irq, void *dev_id)
  46. {
  47. if (__raw_readl(HSTIM_INT) & MATCH0_INT) {
  48. write_seqlock(&xtime_lock);
  49. do {
  50. timer_tick();
  51. /*
  52. * this algorithm takes care of possible delay
  53. * for this interrupt handling longer than a normal
  54. * timer period
  55. */
  56. __raw_writel(__raw_readl(HSTIM_MATCH0) + LATCH,
  57. HSTIM_MATCH0);
  58. __raw_writel(MATCH0_INT, HSTIM_INT); /* clear interrupt */
  59. /*
  60. * The goal is to keep incrementing HSTIM_MATCH0
  61. * register until HSTIM_MATCH0 indicates time after
  62. * what HSTIM_COUNTER indicates.
  63. */
  64. } while ((signed)
  65. (__raw_readl(HSTIM_MATCH0) -
  66. __raw_readl(HSTIM_COUNTER)) < 0);
  67. write_sequnlock(&xtime_lock);
  68. }
  69. return IRQ_HANDLED;
  70. }
  71. static struct irqaction pnx4008_timer_irq = {
  72. .name = "PNX4008 Tick Timer",
  73. .flags = IRQF_DISABLED | IRQF_TIMER,
  74. .handler = pnx4008_timer_interrupt
  75. };
  76. /*!
  77. * Set up timer and timer interrupt.
  78. */
  79. static __init void pnx4008_setup_timer(void)
  80. {
  81. __raw_writel(RESET_COUNT, MSTIM_CTRL);
  82. while (__raw_readl(MSTIM_COUNTER)) ; /* wait for reset to complete. 100% guarantee event */
  83. __raw_writel(0, MSTIM_CTRL); /* stop the timer */
  84. __raw_writel(0, MSTIM_MCTRL);
  85. __raw_writel(RESET_COUNT, HSTIM_CTRL);
  86. while (__raw_readl(HSTIM_COUNTER)) ; /* wait for reset to complete. 100% guarantee event */
  87. __raw_writel(0, HSTIM_CTRL);
  88. __raw_writel(0, HSTIM_MCTRL);
  89. __raw_writel(0, HSTIM_CCR);
  90. __raw_writel(12, HSTIM_PMATCH); /* scale down to 1 MHZ */
  91. __raw_writel(LATCH, HSTIM_MATCH0);
  92. __raw_writel(MR0_INT, HSTIM_MCTRL);
  93. setup_irq(HSTIMER_INT, &pnx4008_timer_irq);
  94. __raw_writel(COUNT_ENAB | DEBUG_EN, HSTIM_CTRL); /*start timer, stop when JTAG active */
  95. }
  96. /* Timer Clock Control in PM register */
  97. #define TIMCLK_CTRL_REG IO_ADDRESS((PNX4008_PWRMAN_BASE + 0xBC))
  98. #define WATCHDOG_CLK_EN 1
  99. #define TIMER_CLK_EN 2 /* HS and MS timers? */
  100. static u32 timclk_ctrl_reg_save;
  101. void pnx4008_timer_suspend(void)
  102. {
  103. timclk_ctrl_reg_save = __raw_readl(TIMCLK_CTRL_REG);
  104. __raw_writel(0, TIMCLK_CTRL_REG); /* disable timers */
  105. }
  106. void pnx4008_timer_resume(void)
  107. {
  108. __raw_writel(timclk_ctrl_reg_save, TIMCLK_CTRL_REG); /* enable timers */
  109. }
  110. struct sys_timer pnx4008_timer = {
  111. .init = pnx4008_setup_timer,
  112. .offset = pnx4008_gettimeoffset,
  113. .suspend = pnx4008_timer_suspend,
  114. .resume = pnx4008_timer_resume,
  115. };