NS16550.h

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/*
 * Copyright (C) 2019 Niek Linnenbank
 *
 * This program 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
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef __SERVER_SERIAL_NS16550_H
#define __SERVER_SERIAL_NS16550_H
 
#include <Log.h>
#include <Types.h>
#include "SerialDevice.h"
 
class NS16550 : public SerialDevice
{
  private:
 
    enum Registers
    {
        ReceiveBuffer     = 0x00, /* 0 */
        TransmitHolding   = 0x00,
        DivisorLatchLow   = 0x00,
        DivisorLatchHigh  = 0x04, /* 1 */
        InterruptEnable   = 0x04,
        InterruptIdentity = 0x08, /* 2 */
        FifoControl       = 0x08,
        LineControl       = 0x0C, /* 3 */
        ModemControl      = 0x10, /* 4 */
        LineStatus        = 0x14, /* 5 */
        ModemStatus       = 0x18, /* 6 */
        Scratch           = 0x1C, /* 7 */
        UartStatus        = 0x7C, /* 31 */
        TransmitFifoLvl   = 0x80
    };
 
    enum InterruptEnableFlags
    {
        ReceiveDataInterrupt = (1 << 0)
    };
 
    enum InterruptIdentityFlags
    {
        InterruptIdentityFifoEnable = (0x3 << 6)
    };
 
    enum FifoControlFlags
    {
        FifoControlTrigger1 = (0),
        FifoControlEnable   = (1 << 0)
    };
 
    enum LineControlFlags
    {
        LineControlDivisorLatch = (1 << 7),
        LineControl8Bits        = (0x3 << 0)
    };
 
    enum LineStatusFlags
    {
        LineStatusTxEmpty   = (1 << 6),
        LineStatusDataReady = (1 << 0)
    };
 
    enum UartStatusFlags
    {
        UartStatusReceiveAvailable = (1 << 2),
        UartStatusTransmitAvailable = (1 << 1),
        UartStatusBusy = (1 << 0)
    };
 
  public:
 
    NS16550(const u32 irq);
 
    virtual FileSystem::Result initialize();
 
    virtual FileSystem::Result interrupt(const Size vector);
 
    virtual FileSystem::Result read(IOBuffer & buffer,
                                    Size & size,
                                    const Size offset);
 
    virtual FileSystem::Result write(IOBuffer & buffer,
                                     Size & size,
                                     const Size offset);
 
  private:
 
    void setDivisorLatch(bool enabled);
};
 
#endif /* __SERVER_SERIAL_NS16550_H */