//----------------------------------------------------------------------------//
//                           GNU GPL OS/K                                     //
//                                                                            //
//  Desc:  Interrupt 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 <kernel/base.h>
#include <kernel/iomisc.h>
#include <extras/buf.h>
#include <kernel/time.h>

extern void RtcIsr(void);

ulong IoRtcTicks = 0;

Time_t IoRtcTime;

void IoSetupRtc(void)
{
    IdtRegisterIrq(RtcIsr, 0x28, 0x8E);
}

void IoGetTimeFromRtc(void)
{
    char time24or12Mode;
    Time_t lastTime;

    char updateInProgress = 1;

    while(updateInProgress) {                       // wait while the RTC updates its value
        IoWriteByteOnPort(0x70, 0x0A);
        updateInProgress = (IoReadByteFromPort(0x71) & 0x80);
    }

    IoWriteByteOnPort(0x70, 0x0);
    IoRtcTime.sec = IoReadByteFromPort(0x71);
    IoWriteByteOnPort(0x70, 0x02);
    IoRtcTime.min = IoReadByteFromPort(0x71);
    IoWriteByteOnPort(0x70, 0x04);
    IoRtcTime.hour = IoReadByteFromPort(0x71);
    IoWriteByteOnPort(0x70, 0x06);
    IoRtcTime.weekday = IoReadByteFromPort(0x71);
    IoWriteByteOnPort(0x70, 0x07);
    IoRtcTime.day = IoReadByteFromPort(0x71);
    IoWriteByteOnPort(0x70, 0x08);
    IoRtcTime.month = IoReadByteFromPort(0x71);
    IoWriteByteOnPort(0x70, 0x09);
    IoRtcTime.year = IoReadByteFromPort(0x71);
    IoWriteByteOnPort(0x70, 0x32);
    IoRtcTime.century = IoReadByteFromPort(0x71);

    // Now while we don't get the same value, read the registers (ensure data are valid)
    do {
        lastTime.sec = IoRtcTime.sec;
        lastTime.min = IoRtcTime.min;
        lastTime.hour = IoRtcTime.hour;
        lastTime.weekday = IoRtcTime.weekday;
        lastTime.day = IoRtcTime.day;
        lastTime.month = IoRtcTime.month;
        lastTime.year = IoRtcTime.year;
        lastTime.century = IoRtcTime.century;

        while(updateInProgress) {                       // wait while the RTC updates its value
            IoWriteByteOnPort(0x70, 0x0A);
            updateInProgress = (IoReadByteFromPort(0x71) & 0x80);
        }

        IoWriteByteOnPort(0x70, 0x0);
        IoRtcTime.sec = IoReadByteFromPort(0x71);
        IoWriteByteOnPort(0x70, 0x02);
        IoRtcTime.min = IoReadByteFromPort(0x71);
        IoWriteByteOnPort(0x70, 0x04);
        IoRtcTime.hour = IoReadByteFromPort(0x71);
        IoWriteByteOnPort(0x70, 0x06);
        IoRtcTime.weekday = IoReadByteFromPort(0x71);
        IoWriteByteOnPort(0x70, 0x07);
        IoRtcTime.day = IoReadByteFromPort(0x71);
        IoWriteByteOnPort(0x70, 0x08);
        IoRtcTime.month = IoReadByteFromPort(0x71);
        IoWriteByteOnPort(0x70, 0x09);
        IoRtcTime.year = IoReadByteFromPort(0x71);
        IoWriteByteOnPort(0x70, 0x32);
        IoRtcTime.century = IoReadByteFromPort(0x71);

    } while ( (lastTime.sec  != IoRtcTime.sec) || (lastTime.min  != IoRtcTime.min) ||
              (lastTime.hour  != IoRtcTime.hour) || (lastTime.weekday  != IoRtcTime.weekday) ||
              (lastTime.day  != IoRtcTime.day) || (lastTime.month  != IoRtcTime.month) ||
              (lastTime.year  != IoRtcTime.year) || (lastTime.century  != IoRtcTime.century)
          );

    IoWriteByteOnPort(0x70, 0x32);
    time24or12Mode = IoReadByteFromPort(0x71);

    // Convert to binary if it is necessary
    if (!(time24or12Mode & 0x04)) {
        IoRtcTime.sec = (IoRtcTime.sec & 0x0F)
                        + ((IoRtcTime.sec / 16) * 10);
        IoRtcTime.min = (IoRtcTime.min & 0x0F)
                        + ((IoRtcTime.min / 16) * 10);
        IoRtcTime.hour = ( (IoRtcTime.hour & 0x0F)
                        + (((IoRtcTime.hour & 0x70) / 16) * 10) )
                        | (IoRtcTime.hour & 0x80);
        IoRtcTime.day = (IoRtcTime.day & 0x0F) + ((IoRtcTime.day / 16) * 10);
        IoRtcTime.month = (IoRtcTime.month & 0x0F)
                        + ((IoRtcTime.month / 16) * 10);
        IoRtcTime.year = (IoRtcTime.year & 0x0F)
                        + ((IoRtcTime.year / 16) * 10);
        IoRtcTime.century = (IoRtcTime.century & 0x0F)
                        + ((IoRtcTime.century / 16) * 10);
    }

    // Convert 12 to 24 hour if necessary
    if (!(time24or12Mode & 0x02) && (IoRtcTime.hour & 0x80)) {
        IoRtcTime.hour = ((IoRtcTime.hour & 0x7F) + 12) % 24;
    }
}

void IoEnableRtc(void)
{
    ulong flags = KePauseIRQs();
    char readedInterruptConfig;
    char readedRegister;
    char readedIrqs;
    uchar RtcRate;

    // Setting up the register control and interrupt rates
    RtcRate = 0x05;

    IoWriteByteOnPort(0x70, 0x8B);
    readedRegister = IoReadByteFromPort(0x71);
    IoWriteByteOnPort(0x70, 0x8B);                  // Because reading flushes
    IoWriteByteOnPort(0x71, readedRegister | 0x40);

    IoWriteByteOnPort(0x70, 0x8A);
    readedInterruptConfig = IoReadByteFromPort(0x71);
    IoWriteByteOnPort(0x70, 0x8A);                  // Because reading flushes
    IoWriteByteOnPort(0x71, (readedInterruptConfig & 0xF0) | RtcRate);
    IoWriteByteOnPort(0x70, 0x0C);
    IoReadByteFromPort(0x71);                       // Flush

    // Setting up the IRQs
    readedIrqs = IoReadByteFromPort(0xA1);
    IoWriteByteOnPort(0xA1, 0xFE & readedIrqs);     // Enables IRQ on PIC 2
    readedIrqs = IoReadByteFromPort(0x21);
    IoWriteByteOnPort(0x21, 0xFB & readedIrqs);     // Enables IRQ on PIC 1

    // clean-up
    IoWriteByteOnPort(0x70, 0x0C);                  // Select status reg C
    IoReadByteFromPort(0x71);                       // Flush

    IoGetTimeFromRtc();
    KeRestoreIRQs(flags);
    IoEnableNMI();
}

void RtcHandler(void)
{
    //bprintf(BStdOut, " *RTC - ");
    IoWriteByteOnPort(0x70, 0x0C);  // Selects status reg C
    IoReadByteFromPort(0x71);       // Flush
    IoRtcTicks++;
    IoSendEOItoPIC(0x28);
    //bprintf(BStdOut, " - EOI* ");
}

void IoPrintRtcTime(void)
{
    KernLog("[RTC Time] %s %d/%d/%d ; %d:%d:%d\n",
            WeekDays[IoRtcTime.weekday],
            IoRtcTime.day,
            IoRtcTime.month,
            IoRtcTime.year + IoRtcTime.century*100,
            IoRtcTime.hour,
            IoRtcTime.min,
            IoRtcTime.sec
            );
}

Time_t* IoGetRtcTime(void)
{
    return &IoRtcTime;
}

ulong IoGetRtcTicks(void)
{
    return IoRtcTicks;
}