source: rtems/c/src/lib/libcpu/m68k/mcf5272/clock/ckinit.c @ 5039d92

/*
 *  Clock Driver for MCF5272 CPU
 *
 *  This driver initailizes timer1 on the MCF5272 as the
 *  main system clock
 */

/*
 *  Copyright 2004 Cogent Computer Systems
 *  Author: Jay Monkman <jtm@lopingdog.com>
 *
 *  Based on MCF5206 clock driver by
 *    Victor V. Vengerov <vvv@oktet.ru>
 *
 *  Based on work:
 *    David Fiddes, D.J@fiddes.surfaid.org
 *    http://www.calm.hw.ac.uk/davidf/coldfire/
 *
 *  COPYRIGHT (c) 1989-1998.
 *  On-Line Applications Research Corporation (OAR).
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.rtems.org/license/LICENSE.
 */

#include <stdlib.h>
#include <bsp.h>
#include <rtems/libio.h>
#include <mcf5272/mcf5272.h>

/*
 * Clock_driver_ticks is a monotonically increasing counter of the
 * number of clock ticks since the driver was initialized.
 */
volatile uint32_t Clock_driver_ticks;

rtems_isr (*rtems_clock_hook)(rtems_vector_number) = NULL;

static rtems_isr
Clock_isr (rtems_vector_number vector)
{
  /* Clear pending interrupt... */
  g_timer_regs->ter1 = MCF5272_TER_REF | MCF5272_TER_CAP;

  /* Announce the clock tick */
  Clock_driver_ticks++;
  rtems_clock_tick();
  if (rtems_clock_hook != NULL) {
      rtems_clock_hook(vector);
  }
}

void
Clock_exit(void)
{
  uint32_t icr;

  /* disable all timer1 interrupts */
  icr = g_intctrl_regs->icr1;
  icr = icr & ~(MCF5272_ICR1_TMR1_MASK | MCF5272_ICR1_TMR1_PI);
  icr |= (MCF5272_ICR1_TMR1_IPL(0) | MCF5272_ICR1_TMR1_PI);
  g_intctrl_regs->icr1 = icr;

  /* reset timer1 */
  g_timer_regs->tmr1 = MCF5272_TMR_CLK_STOP;

  /* clear pending */
  g_timer_regs->ter1 = MCF5272_TER_REF | MCF5272_TER_CAP;
}

static void
Install_clock(rtems_isr_entry clock_isr)
{
  uint32_t icr;

  Clock_driver_ticks = 0;

  /* Register the interrupt handler */
  set_vector(clock_isr, BSP_INTVEC_TMR1, 1);

  /* Reset timer 1 */
  g_timer_regs->tmr1 = MCF5272_TMR_RST;
  g_timer_regs->tmr1 = MCF5272_TMR_CLK_STOP;
  g_timer_regs->tmr1 = MCF5272_TMR_RST;
  g_timer_regs->tcn1 = 0;  /* reset counter */
  g_timer_regs->ter1 = MCF5272_TER_REF | MCF5272_TER_CAP;

  /* Set Timer 1 prescaler so that it counts in microseconds */
  g_timer_regs->tmr1 = (
      ((((BSP_SYSTEM_FREQUENCY / 1000000) - 1) << MCF5272_TMR_PS_SHIFT) |
       MCF5272_TMR_CE_DISABLE                                      |
       MCF5272_TMR_ORI                                             |
       MCF5272_TMR_FRR                                             |
       MCF5272_TMR_CLK_MSTR                                        |
       MCF5272_TMR_RST));

  /* Set the timer timeout value from the BSP config */
  g_timer_regs->trr1 = rtems_configuration_get_microseconds_per_tick() - 1;

  /* Feed system frequency to the timer */
  g_timer_regs->tmr1 |= MCF5272_TMR_CLK_MSTR;

  /* Configure timer1 interrupts */
  icr = g_intctrl_regs->icr1;
  icr = icr & ~(MCF5272_ICR1_TMR1_MASK | MCF5272_ICR1_TMR1_PI);
  icr |= (MCF5272_ICR1_TMR1_IPL(BSP_INTLVL_TMR1) | MCF5272_ICR1_TMR1_PI);
  g_intctrl_regs->icr1 = icr;

  /* Register the driver exit procedure so we can shutdown */
  atexit(Clock_exit);
}

rtems_device_driver
Clock_initialize(
  rtems_device_major_number major,
  rtems_device_minor_number minor,
  void *pargp
)
{
  Install_clock (Clock_isr);

  return RTEMS_SUCCESSFUL;
}