/*
    intel8254.c, Copyright  (c) by Matthias Gries,
    Swiss Federal Institute of Technology,
    Computer Engineering and Networks Laboratory.

    TOPSY -- A Teachable Operating System.
             Implementation of a tiny and simple
             micro kernel for teaching purposes.

    For further information, please visit http://www.tik.ee.ethz.ch/~topsy

    This software is provided under the terms of the GNU General Public Licence.

    A full copy of the GNU GPL is provided in the file COPYING found in the 
    development root of Topsy.
*/
/*

	File:                  $Source: /usr/drwho/vault/cvs/topsy/Topsy/IO/Drivers/intel8254.c,v $
 	Author(s):             Matthias Gries
 	Affiliation:           ETH Zuerich, TIK
 	Version:               $Revision: 1.7 $
 	Creation Date:         
 	Last Date of Change:   $Date: 1999/12/13 21:48:26 $      by: $Author: ruf $
	
	
*/

/* uncomment the next line to enable the timer interrupt handler */
/* #define TIMER_INTERRUPT_HANDLER_ON */

#include "Drivers/intel8254.h"
#include "Messages.h"
#include "IODevice.h"
#include "Syscall.h"

typedef struct {
  ThreadId callerid; /* ThreadId of calling thread */
  ThreadId timerid;  /* ThreadId of Timer-driver thread */
}timer_temp;


void timer1_interruptHandler(IODevice this) 
{
  /* Stop the clock (reset). If not done the interrupt is generated once again and again ... */
  tmResetClockInterrupt(CLOCK1);
  /* this is nolonger done in "intDispatcher()" in TMHal.c */

  /* ioConsolePutString("interrupt handler timer1\n"); */

   if (this->extension != NULL) /* timer has been started using msg handler */ 
     { 
#ifdef TIMER_INTERRUPT_HANDLER_ON
       Message sendmsg; 
      
       sendmsg.from =                 ; 
       sendmsg.id   =                 ;  

       if ( kSend(                       ,               ) != TM_OK )  
         PANIC("timer interrupt handler unable to send message"); 
       
       hmFree(                            );  
       this->extension = NULL; 

       /* count-down finished, no further interrupts */
#endif
     } 
}


Error timer1_init(IODevice this) 
{
  /* ioConsolePutString("timer init\n"); */

  if (this->isInitialised == FALSE) 
    {
      this->isInitialised = TRUE;
      this->extension = NULL; /* just to be sure */
    }
  return IO_INITOK;
}


Error timer1_stop(IODevice this) 
{
  /* ioConsolePutString("timer stop\n"); */

  if (this->isInitialised) 
    this->isInitialised = FALSE; /* Unset Initialized flag */    
  
  if (this->extension != NULL) hmFree((Address) this->extension);
  this->extension = NULL;
  
  return IO_CLOSEOK;
}


void timer1_messageHandler(IODevice this, Message* msg)
{
  if ((msg->id == IO_TIMER_START) && (msg->msg.ioTimer.period != 0))
    {
      ThreadId dummy;
      /* ioConsolePutString("timer message handler : start message received\n"); */
      
      if ((msg->msg.ioTimer.period > 0) && (msg->msg.ioTimer.period <= 1750))
	{
	  if (setClockValue(CLOCK1, msg->msg.ioTimer.period, SWTRIGGER) != TM_OK)
	    PANIC("timer1 could not be properly configured");
	}
      else 
        {
	  ioConsolePutString("period not within timer range (1 to 1750 [ms]) \n");
	  return;
      	}
      
      if (HM_ALLOCFAILED == hmAlloc((Address*) &(this->extension), sizeof(timer_temp)))
	PANIC("no heap space left in timer1_messageHandler");
      else ((timer_temp*)(this->extension))->callerid = msg->from; /* used in msg interrupt handler */
	  
      if (tmGetInfo(SELF, &(((timer_temp*)(this->extension))->timerid), &dummy) != TM_INFOOK)  
	/* get own ThreadId */ 
	ioConsolePutString("tmGetInfo failed in timer1-msghandler\n");	
    }

  else ioConsolePutString("WARNING: message not understood by timer1 message handler\n");
}