gem5/dev/uart8250.hh

/*
 * Copyright (c) 2005 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @file
 * Defines a 8250 UART
 */

#ifndef __TSUNAMI_UART_HH__
#define __TSUNAMI_UART_HH__

#include "dev/tsunamireg.h"
#include "base/range.hh"
#include "dev/io_device.hh"
#include "dev/uart.hh"


/* UART8250 Interrupt ID Register
 *  bit 0    Interrupt Pending 0 = true, 1 = false
 *  bit 2:1  ID of highest priority interrupt
 *  bit 7:3  zeroes
 */
#define IIR_NOPEND 0x1

// Interrupt IDs
#define IIR_MODEM 0x00 /* Modem Status (lowest priority) */
#define IIR_TXID  0x02 /* Tx Data */
#define IIR_RXID  0x04 /* Rx Data */
#define IIR_LINE  0x06 /* Rx Line Status (highest priority)*/

class SimConsole;
class Platform;

class Uart8250 : public Uart
{


  protected:
    uint8_t IER, DLAB, LCR, MCR;

    class IntrEvent : public Event
    {
        protected:
            Uart8250 *uart;
            int intrBit;
        public:
            IntrEvent(Uart8250 *u, int bit);
            virtual void process();
            virtual const char *description();
            void scheduleIntr();
    };

    IntrEvent txIntrEvent;
    IntrEvent rxIntrEvent;

  public:
    Uart8250(const std::string &name, SimConsole *c, MemoryController *mmu,
         Addr a, Addr s, HierParams *hier, Bus *pio_bus, Tick pio_latency,
         Platform *p);

    virtual Fault * read(MemReqPtr &req, uint8_t *data);
    virtual Fault * write(MemReqPtr &req, const uint8_t *data);


    /**
     * Inform the uart that there is data available.
     */
    virtual void dataAvailable();


    /**
     * Return if we have an interrupt pending
     * @return interrupt status
     */
    virtual bool intStatus() { return status ? true : false; }

    virtual void serialize(std::ostream &os);
    virtual void unserialize(Checkpoint *cp, const std::string &section);

};

#endif // __TSUNAMI_UART_HH__