[ts-7000] How to disable irq when I read the free running timer4

["danjperron" <>]

I create an extended 64 bit version of the free running timer.


But if I want to use it into some threads, I need to ensure that 2
threads reading tc4 will read the correct values;

  No process interrupts the reading of the low 32 bits tc4 and the
high 32 bits tc4 sequence. I just don't want a thread reading tc4  at
the same time than an other one reading the high 32 bits.

  
 check my routine , (inspire from Jesse Off ,messages #10), GetFRTime()


////// FreeRunningTimer.c
  
#include<stdlib.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/mman.h>
#include<stdio.h>
#include<fcntl.h>

#include "FreeRunningTimer.h"


int FRTimerHandle=-1;

unsigned char *FRTimerBase=NULL;
unsigned long *FRTimerLo=NULL;
unsigned long *FRTimerHi=NULL;

unsigned long FRTimerExtHi=0; // use to go behond 40 bit (extended)



/* InitFRTimer
 * map physical address 
 * return 0 if we can't mapped
 * return 1 if everything ok
 */

int InitFRTimer(void)
{
        FRTimerHandle= open("/dev/mem",O_RDWR);
        if(FRTimerHandle<0) return(0);
        FRTimerBase =
mmap(0,getpagesize(),PROT_WRITE|PROT_READ,MAP_SHARED,FRTimerHandle,0x80810000UL);
        if(FRTimerBase  == NULL)
        {
                CloseFRTimer();
                return(0);
        }
        FRTimerLo=  (unsigned long *) (FRTimerBase + 0x60UL); // get Least
significant long
        
        FRTimerHi=  (unsigned long *) (FRTimerBase + 0x64UL); //  get Most
significant long

    *FRTimerHi=0x100;  // start Timer           
    return(1);
}


/*  CloseFRTimer
 *  release map of physical address
 */

void CloseFRTimer(void)
{

   if(FRTimerHandle>=0)
   {
           if(FRTimerBase)      
           munmap(FRTimerBase,getpagesize());
           close(FRTimerHandle);
   }
    FRTimerHandle=-1;
        FRTimerBase=NULL;
        FRTimerLo=NULL;
        FRTimerHi=NULL;
}

/* ResetFRTimer
 *  Reset and enable Free running timer
 */
void ResetFRTimer(void)
{
   *FRTimerHi= 0;  
   *FRTimerHi= 0x100; // enable free running Timer
   FRTimerExtHi=0;     // reset extended bit
}


/* GetFRTimer
 *  return current free running timer value
 */


unsigned long long GetFRTimer(void)
{
   // need to be run at least once every 300 hours
   // for the extended bit system to work!

   unsigned long long tval;
   
   unsigned long HiVal;
    
    // need to disable irq here
    //
    //  ??????
    
    tval = *FRTimerLo;
    
    
    HiVal= *FRTimerHi & 0xff;
    
    // need to enable irq here
    //
    //  ?????
    
    
       
    if(HiVal  < (FRTimerExtHi & 0xff))
    {
        // ok we got a wrapped Timer;
        
        FRTimerExtHi += 0x100;  // increment bit 40
    }
        FRTimerExtHi &= ~0xff;
        FRTimerExtHi |= HiVal;
        
      tval |= ((unsigned long long ) FRTimerExtHi) << 32;
    
    return(tval);
}


                

////// FreeRunningTimer.h

#ifndef FREE_RUNNING_TIMER_H
#define FREE_RUNNING_TIMER_H


int InitFRTimer(void);
void CloseFRTimer(void);
void ResetFRTimer(void);
unsigned long long GetFRTimer(void);

#define FRTimerToMs(A)  (((unsigned long long) A) / 984ULL)
#define MsToFRTimer(A)  (((unsigned long long) A) * 984ULL)

//#define FRTimerToMs(A)  ((unsigned long long) A >> 10)
//#define MsToFRTimer(A)  ((unsigned long long) A << 10)

int IsFRTimerPassed(unsigned long long BaseTime,\
                   unsigned long long CurrentTime);
#endif





////A test program to check if the FRTimer works!

#include<stdio.h>
#include<stdlib.h>
#include "freeRunningTimer.h"



#define OUTPUT_ON 1
#define OUTPUT_OFF 0
 

 void Output(int Value)
 {
        static int phy_out=0; // emulate real output
        unsigned long long tcount;
        
        tcount= GetFRTimer();
        if(phy_out==OUTPUT_ON)
          {
                if(!Value)
                  {
                        phy_out=OUTPUT_OFF; // emulate off
                  printf("Output OFF at  %llu
(ms)\n",FRTimerToMs(tcount));fflush(stdout);
                  }
          }
          else
          {
                if(Value)
                  {
                        
                        phy_out=OUTPUT_ON; // emulate  on 
                  printf("Output ON at %llu
ms\n",FRTimerToMs(tcount));fflush(stdout);
                  }
          }
 }        
        
 
 
 int main(void)
 {
 
    int cycle;
 
    unsigned long long  basecount;
  unsigned long long  currentcount;
 
 
    if(!InitFRTimer())
    {
        printf("Unable to Map Free running Timer\n");
        return(1);
    }   
        
        ResetFRTimer();
        basecount =0;


        for(cycle=0;cycle<5;cycle++)
        {
        printf("cycle %d\n",cycle);fflush(stdout);
        while(1)
        {
                    currentcount = GetFRTimer()- basecount;


            if(FRTimerToMs(currentcount) < 1330ULL) // 1.33 seconds
               Output(OUTPUT_ON);
            else
               Output(OUTPUT_OFF);
               
            if(FRTimerToMs(currentcount) > 5000ULL) // 5 seconds
               {
                 basecount +=  MsToFRTimer(5000ULL);  // basecount to
next cycle
                 break;
               }
        }
        }
        
        
                
        printf("Done\n");
        
        CloseFRTimer();
        
  return(0);
 }
        

   
  









 
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