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/*-------------------------------------------------------------------------+

| ckinit.c v1.1 - PC386 BSP - 1997/08/07

+--------------------------------------------------------------------------+

| This file contains the PC386 clock package.

+--------------------------------------------------------------------------+

| (C) Copyright 1997 -

| - NavIST Group - Real-Time Distributed Systems and Industrial Automation

|

| http://pandora.ist.utl.pt

|

| Instituto Superior Tecnico * Lisboa * PORTUGAL

+--------------------------------------------------------------------------+

| Disclaimer:

|

| This file is provided "AS IS" without warranty of any kind, either

| expressed or implied.

+--------------------------------------------------------------------------+

| This code is based on:

|   ckinit.c,v 1.4 1995/12/19 20:07:13 joel Exp - go32 BSP

| With the following copyright notice:

| **************************************************************************

| *  COPYRIGHT (c) 1989-1999.

| *  On-Line Applications Research Corporation (OAR).

| *

| *  The license and distribution terms for this file may be

| *  found in found in the file LICENSE in this distribution or at

| *  http://www.OARcorp.com/rtems/license.html.

| **************************************************************************

|

|  $Id: ckinit.c,v 1.2 2001-09-27 11:59:47 chris Exp $

+--------------------------------------------------------------------------*/

#include <stdlib.h>

#include <bsp.h>

#include <irq.h>

#include <rtems/libio.h>

/*-------------------------------------------------------------------------+

| Macros

+--------------------------------------------------------------------------*/

#if 0

/* This was dropped in the last revision.  Its a nice thing to know. */

#define TICKS_PER_SECOND() \

          (1000000 / (Clock_isrs_per_tick * microseconds_per_isr))

#endif /* 0 */

/*-------------------------------------------------------------------------+

| Global Variables

+--------------------------------------------------------------------------*/

volatile rtems_unsigned32 Clock_driver_ticks;   /* Tick (interrupt) counter. */

         rtems_unsigned32 Clock_isrs_per_tick;  /* ISRs per tick.            */

         rtems_unsigned32 Clock_isrs;           /* ISRs until next tick.     */

/* The following variables are set by the clock driver during its init */

rtems_device_major_number rtems_clock_major = ~0;

rtems_device_minor_number rtems_clock_minor;

/*-------------------------------------------------------------------------+

|         Function: clockIsr

|      Description: Interrupt Service Routine for clock (0h) interruption.

| Global Variables: Clock_driver_ticks, Clock_isrs.

|        Arguments: vector - standard RTEMS argument - see documentation.

|          Returns: standard return value - see documentation.

+--------------------------------------------------------------------------*/

static void clockIsr()

{

  /*-------------------------------------------------------------------------+

  | PLEASE NOTE: The following is directly transcribed from the go32 BSP for

  |              those who wish to use it with PENTIUM based machine. It needs

  |              to be correctly integrated with the rest of the code!!!

  +--------------------------------------------------------------------------*/

#if 0 && defined(pentium) /* more accurate clock for PENTIUMs (not supported) */

  {

    extern long long Last_RDTSC;

    __asm __volatile(".byte 0x0F, 0x31" : "=A" (Last_RDTSC));

  }

#endif /* 0 && pentium */

  Clock_driver_ticks++;

  if ( Clock_isrs == 1 )

  {

    rtems_clock_tick();

    Clock_isrs = Clock_isrs_per_tick;

  }

  else

    Clock_isrs--;

} /* clockIsr */

/*-------------------------------------------------------------------------+

|         Function: Clock_exit

|      Description: Clock cleanup routine at RTEMS exit. NOTE: This routine is

|                   not really necessary, since there will be a reset at exit.

| Global Variables: None.

|        Arguments: None.

|          Returns: Nothing.

+--------------------------------------------------------------------------*/

void clockOff(const rtems_irq_connect_data* unused)

{

  /* reset timer mode to standard (BIOS) value */

  outport_byte(TIMER_MODE, TIMER_SEL0 | TIMER_16BIT | TIMER_RATEGEN);

  outport_byte(TIMER_CNTR0, 0);

  outport_byte(TIMER_CNTR0, 0);

} /* Clock_exit */

/*-------------------------------------------------------------------------+

|         Function: Install_clock

|      Description: Initialize and install clock interrupt handler.

| Global Variables: None.

|        Arguments: None.

|          Returns: Nothing.

+--------------------------------------------------------------------------*/

static void clockOn(const rtems_irq_connect_data* unused)

{

  rtems_unsigned32  microseconds_per_isr;

#if 0

  /* Initialize clock from on-board real time clock.  This breaks the  */

  /* test code which assumes which assumes the application will do it. */

  {

    rtems_time_of_day now;

    /* External Prototypes */

    extern void init_rtc(void);                /* defined in 'rtc.c' */

    extern long rtc_read(rtems_time_of_day *); /* defined in 'rtc.c' */

    init_rtc();

    if (rtc_read(&now) >= 0)

      clock_set(&now);

  }

#endif /* 0 */

  /* Start by assuming hardware counter is large enough, then  scale it until

     it actually fits. */

  Clock_driver_ticks  = 0;

  Clock_isrs_per_tick = 1;

  if (BSP_Configuration.microseconds_per_tick == 0)

    microseconds_per_isr = 10000; /* default 10 ms */

  else

    microseconds_per_isr = BSP_Configuration.microseconds_per_tick;

  while (US_TO_TICK(microseconds_per_isr) > 65535)

  {

    Clock_isrs_per_tick  *= 10;

    microseconds_per_isr /= 10;

  }

  Clock_isrs = Clock_isrs_per_tick; /* Initialize Clock_isrs */

  {

    /* 105/88 approximates TIMER_TICK * 1e-6 */

    rtems_unsigned32 count = US_TO_TICK(microseconds_per_isr);

    outport_byte(TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN);

    outport_byte(TIMER_CNTR0, count >> 0 & 0xff);

    outport_byte(TIMER_CNTR0, count >> 8 & 0xff);

  }

}

int clockIsOn(const rtems_irq_connect_data* unused)

{

  return ((i8259s_cache & 0x1) == 0);

}

static rtems_irq_connect_data clockIrqData = {BSP_PERIODIC_TIMER,

                                              clockIsr,

                                              clockOn,

                                              clockOff,

                                              clockIsOn};

/*-------------------------------------------------------------------------+

| Clock device driver INITIALIZE entry point.

+--------------------------------------------------------------------------+

| Initilizes the clock driver.

+--------------------------------------------------------------------------*/

rtems_device_driver

Clock_initialize(rtems_device_major_number major,

                 rtems_device_minor_number minor,

                 void                      *pargp)

{

  if (!BSP_install_rtems_irq_handler (&clockIrqData)) {

    printk("Unable to initialize system clock\n");

    rtems_fatal_error_occurred(1);

  }

  /* make major/minor avail to others such as shared memory driver */

  rtems_clock_major = major;

  rtems_clock_minor = minor;

  return RTEMS_SUCCESSFUL;

} /* Clock_initialize */

/*-------------------------------------------------------------------------+

| Console device driver CONTROL entry point

+--------------------------------------------------------------------------*/

rtems_device_driver

Clock_control(rtems_device_major_number major,

              rtems_device_minor_number minor,

              void                      *pargp)

{

  if (pargp != NULL)

  {

    rtems_libio_ioctl_args_t *args = pargp;

    /*-------------------------------------------------------------------------+

    | This is hokey, but until we get a defined interface to do this, it will

    | just be this simple...

    +-------------------------------------------------------------------------*/

    if      (args->command == rtems_build_name('I', 'S', 'R', ' '))

      clockIsr();

    else if (args->command == rtems_build_name('N', 'E', 'W', ' '))

    {

      if (!BSP_install_rtems_irq_handler (&clockIrqData)) {

        printk("Error installing clock interrupt handler!\n");

        rtems_fatal_error_occurred(1);

      }

    }

  }

  return RTEMS_SUCCESSFUL;

} /* Clock_control */

void Clock_exit()

{

  BSP_remove_rtems_irq_handler (&clockIrqData);

}

/*-------------------------------------------------------------------------+

| PLEASE NOTE: The following is directly transcribed from the go32 BSP for

|              those who wish to use it with PENTIUM based machine. It needs

|              to be correctly integrated with the rest of the code!!!

+--------------------------------------------------------------------------*/

#if 0 && defined(pentium)

/* This can be used to get extremely accurate timing on a pentium. */

/* It isn't supported. [bryce]                                     */

#define HZ 90.0

volatile long long Last_RDTSC;

#define RDTSC()\

  ({ long long _now; __asm __volatile (".byte 0x0F,0x31":"=A"(_now)); _now; })

long long Kernel_Time_ns( void )

{

  extern rtems_unsigned32 _TOD_Ticks_per_second;

  unsigned  isrs_per_second = Clock_isrs_per_tick * _TOD_Ticks_per_second;

  long long now;

  int       flags;

  disable_intr(flags);

  now = 1e9 * Clock_driver_ticks / isrs_per_second +

        (RDTSC() - Last_RDTSC) * (1000.0/HZ);

  enable_intr(flags);

  return now;

} /* Kernel_Time_ns */

#endif /* 0 && pentium */