/*-------------------------------------------------------------------------+
| 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) 1989-1998.
| * On-Line Applications Research Corporation (OAR).
| * Copyright assigned to U.S. Government, 1994.
| *
| * 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.
| **************************************************************************
|
| $Id$
+--------------------------------------------------------------------------*/
#include <stdlib.h>
#include <bsp.h>
#include <irq.h>
#include <rtems/libio.h>
/*-------------------------------------------------------------------------+
| Constants
+--------------------------------------------------------------------------*/
#define CLOCK_IRQ 0x00 /* Clock IRQ. */
/*-------------------------------------------------------------------------+
| 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 (08h) interruption.
| Global Variables: Clock_driver_ticks, Clock_isrs.
| Arguments: vector - standard RTEMS argument - see documentation.
| Returns: standard return value - see documentation.
+--------------------------------------------------------------------------*/
static rtems_isr
clockIsr(rtems_vector_number vector)
{
/*-------------------------------------------------------------------------+
| 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--;
PC386_ackIrq(vector - PC386_IRQ_VECTOR_BASE);
} /* 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 Clock_exit(void)
{
if (BSP_Configuration.ticks_per_timeslice)
{
/* 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.
+--------------------------------------------------------------------------*/
void
Install_clock(rtems_isr_entry isr)
{
rtems_unsigned32 microseconds_per_isr;
rtems_status_code status;
#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 */
if (BSP_Configuration.ticks_per_timeslice)
{
/* 105/88 approximates TIMER_TICK * 1e-6 */
rtems_unsigned32 count = US_TO_TICK(microseconds_per_isr);
status = PC386_installRtemsIrqHandler(CLOCK_IRQ, isr);
if (status != RTEMS_SUCCESSFUL)
{
printk("Error installing clock interrupt handler!\n");
rtems_fatal_error_occurred(status);
}
outport_byte(TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN);
outport_byte(TIMER_CNTR0, count >> 0 & 0xff);
outport_byte(TIMER_CNTR0, count >> 8 & 0xff);
}
atexit(Clock_exit);
} /* Install_clock */
/*-------------------------------------------------------------------------+
| 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)
{
Install_clock(clockIsr); /* Install the interrupt handler */
/* 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(PC386_IRQ_VECTOR_BASE + CLOCK_IRQ);
else if (args->command == rtems_build_name('N', 'E', 'W', ' '))
{
rtems_status_code status;
status = PC386_installRtemsIrqHandler(CLOCK_IRQ, clockIsr);
if (status != RTEMS_SUCCESSFUL)
{
printk("Error installing clock interrupt handler!\n");
rtems_fatal_error_occurred(status);
}
}
}
return RTEMS_SUCCESSFUL;
} /* Clock_control */
/*-------------------------------------------------------------------------+
| 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 */
