//----------------------------------------------------------------------------//
//                           GNU GPL OS/K                                     //
//                                                                            //
//  Desc:  RTC Time  related functions                                        //
//                                                                            //
//                                                                            //
//  Copyright © 2018-2019 The OS/K Team                                       //
//                                                                            //
//  This file is part of OS/K.                                                //
//                                                                            //
//  OS/K is free software: you can redistribute it and/or modify              //
//  it under the terms of the GNU General Public License as published by      //
//  the Free Software Foundation, either version 3 of the License, or         //
//  any later version.                                                        //
//                                                                            //
//  OS/K is distributed in the hope that it will be useful,                   //
//  but WITHOUT ANY WARRANTY//without even the implied warranty of            //
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             //
//  GNU General Public License for more details.                              //
//                                                                            //
//  You should have received a copy of the GNU General Public License         //
//  along with OS/K.  If not, see <https://www.gnu.org/licenses/>.            //
//----------------------------------------------------------------------------//

#include <lib/buf.h>
#include <ke/time.h>
#include <ke/idt.h>

#define COUNTDONE 1
#define PIT_FREQUENCY 100 // Hz = 10ms

static TimerFilo_t timerFilo[20]; //20 concurrent sleep max
static ulong Ticks = 0;

//
// ISR handler for the Programmable Interval Timer
//
static void HandlePIT(ISRFrame_t *regs)
{
    for (uchar i = 0; i < 20; i++) {

        // debug
        //DebugLog("Hello world of PIT ticks !\n");
        //

        if (timerFilo[i].countDown > 0) {
            timerFilo[i].countDown--;

            if (timerFilo[i].countDown == 0)
                i; //XXX SendMessage a message to timerFifo[i].sema that COUNTDONE;
        }

        KeSendEOItoPIC(0x28);
    }
}

static TimerFilo_t* KeFindTimerBlock(void)
{
    for(uchar i = 0; i < 20; i++) {
        if (timerFilo[i].countDown == 0)
            return &timerFilo[i];
    }

    return NULL;
}

void KeSleep(uint delay)
{
    struct TimerFilo_t *timerBlock;

    if ((timerBlock = (TimerFilo_t*)KeFindTimerBlock()) == NULL)
        return;

    timerBlock->countDown = delay;
    // wait for a message on timerFifo[i].sema
}


void KeEnablePIT(void)
{
    ulong flags = KePauseIRQs();
    char readIrqs;
    uint divisor = 1193180 / PIT_FREQUENCY;

    KeRegisterISR(HandlePIT, 0x20);

    IoWriteByteOnPort(0x43, 0x36);          // 0x34 = 00110100 for rate gen

    IoWriteByteOnPort(0x40, (char)(divisor & 0xFF ));      // low byte of freq
    IoWriteByteOnPort(0x40, (char)((divisor >> 8)& 0xFF)); // high byte of freq

    // Setting up the IRQs
    KeUnmaskIRQ(0);

    DebugLog("\tPIT activated with rate generator mode 10ms\n");

    KeRestoreIRQs(flags);
    KeEnableNMI();
}