ns16550.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

/*
 *  This file contains the TTY driver for the National Semiconductor NS16550.
 *
 *  This part is widely cloned and second sourced.  It is found in a number 
 *  of "Super IO" controllers.
 *
 *  COPYRIGHT (c) 1998 by Radstone Technology
 *
 *
 * THIS FILE IS PROVIDED TO YOU, THE USER, "AS IS", WITHOUT WARRANTY OF ANY
 * KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK
 * AS TO THE QUALITY AND PERFORMANCE OF ALL CODE IN THIS FILE IS WITH YOU.
 *
 * You are hereby granted permission to use, copy, modify, and distribute
 * this file, provided that this notice, plus the above copyright notice
 * and disclaimer, appears in all copies. Radstone Technology will provide
 * no support for this code.
 *
 *  This driver uses the termios pseudo driver.
 */

#include <rtems.h>
#include <rtems/libio.h>
#include <stdlib.h>
#include <ringbuf.h>

#include <libchip/serial.h>
#include <libchip/sersupp.h>
#include "ns16550_p.h"

/*
 * Flow control is only supported when using interrupts
 */

console_flow ns16550_flow_RTSCTS = {
  ns16550_negate_RTS,             /* deviceStopRemoteTx */
  ns16550_assert_RTS              /* deviceStartRemoteTx */
};

console_flow ns16550_flow_DTRCTS = {
  ns16550_negate_DTR,             /* deviceStopRemoteTx */
  ns16550_assert_DTR              /* deviceStartRemoteTx */
};

console_fns ns16550_fns = {
  libchip_serial_default_probe,   /* deviceProbe */
  ns16550_open,                   /* deviceFirstOpen */
  NULL,                           /* deviceLastClose */
  NULL,                           /* deviceRead */
  ns16550_write_support_int,      /* deviceWrite */
  ns16550_initialize_interrupts,  /* deviceInitialize */
  ns16550_write_polled,           /* deviceWritePolled */
  ns16550_set_attributes,         /* deviceSetAttributes */
  TRUE                            /* deviceOutputUsesInterrupts */
};

console_fns ns16550_fns_polled = {
  libchip_serial_default_probe,        /* deviceProbe */
  ns16550_open,                        /* deviceFirstOpen */
  ns16550_close,                       /* deviceLastClose */
  ns16550_inbyte_nonblocking_polled,   /* deviceRead */
  ns16550_write_support_polled,        /* deviceWrite */
  ns16550_init,                        /* deviceInitialize */
  ns16550_write_polled,                /* deviceWritePolled */
  ns16550_set_attributes,              /* deviceSetAttributes */
  FALSE                                /* deviceOutputUsesInterrupts */
};

extern void set_vector( rtems_isr_entry, rtems_vector_number, int );

/*
 *  ns16550_init
 */

NS16550_STATIC void ns16550_init(int minor)
{
  unsigned32              pNS16550;
  unsigned8               ucTrash;
  unsigned8               ucDataByte;
  unsigned32              ulBaudDivisor;
  ns16550_context        *pns16550Context;
  setRegister_f           setReg;
  getRegister_f           getReg;

  pns16550Context=(ns16550_context *)malloc(sizeof(ns16550_context));

  Console_Port_Data[minor].pDeviceContext=(void *)pns16550Context;
  pns16550Context->ucModemCtrl=SP_MODEM_IRQ;

  pNS16550 = Console_Port_Tbl[minor].ulCtrlPort1;
  setReg   = Console_Port_Tbl[minor].setRegister;
  getReg   = Console_Port_Tbl[minor].getRegister;

  /* Clear the divisor latch, clear all interrupt enables,
   * and reset and
   * disable the FIFO's.
   */

  (*setReg)(pNS16550, NS16550_LINE_CONTROL, 0x0);
  ns16550_enable_interrupts(minor, NS16550_DISABLE_ALL_INTR);

  /* Set the divisor latch and set the baud rate. */

  ulBaudDivisor = NS16550_Baud(
    (unsigned32) Console_Port_Tbl[minor].ulClock,
    (unsigned32) Console_Port_Tbl[minor].pDeviceParams
  );
  ucDataByte = SP_LINE_DLAB;
  (*setReg)(pNS16550, NS16550_LINE_CONTROL, ucDataByte);

  /* XXX */
  (*setReg)(pNS16550, NS16550_TRANSMIT_BUFFER, ulBaudDivisor&0xff);
  (*setReg)(pNS16550, NS16550_INTERRUPT_ENABLE, (ulBaudDivisor>>8)&0xff);

  /* Clear the divisor latch and set the character size to eight bits */
  /* with one stop bit and no parity checking. */
  ucDataByte = EIGHT_BITS;
  (*setReg)(pNS16550, NS16550_LINE_CONTROL, ucDataByte);

  /* Enable and reset transmit and receive FIFOs. TJA     */
  ucDataByte = SP_FIFO_ENABLE;
  (*setReg)(pNS16550, NS16550_FIFO_CONTROL, ucDataByte);

  ucDataByte = SP_FIFO_ENABLE | SP_FIFO_RXRST | SP_FIFO_TXRST;
  (*setReg)(pNS16550, NS16550_FIFO_CONTROL, ucDataByte);

  ns16550_enable_interrupts(minor, NS16550_DISABLE_ALL_INTR);

  /* Set data terminal ready. */
  /* And open interrupt tristate line */
  (*setReg)(pNS16550, NS16550_MODEM_CONTROL,pns16550Context->ucModemCtrl);

  ucTrash = (*getReg)(pNS16550, NS16550_LINE_STATUS );
  ucTrash = (*getReg)(pNS16550, NS16550_RECEIVE_BUFFER );
}

/*
 *  ns16550_open
 */

NS16550_STATIC int ns16550_open(
  int      major,
  int      minor,
  void    * arg
)
{
  /*
   * Assert DTR
   */

  if(Console_Port_Tbl[minor].pDeviceFlow != &ns16550_flow_DTRCTS) {
    ns16550_assert_DTR(minor);
  }

  return(RTEMS_SUCCESSFUL);
}

/*
 *  ns16550_close
 */

NS16550_STATIC int ns16550_close(
  int      major,
  int      minor,
  void    * arg
)
{
  /*
   * Negate DTR
   */
  if(Console_Port_Tbl[minor].pDeviceFlow != &ns16550_flow_DTRCTS) {
    ns16550_negate_DTR(minor);
  }

  return(RTEMS_SUCCESSFUL);
}

/* 
 *  ns16550_write_polled
 */

NS16550_STATIC void ns16550_write_polled(
  int   minor, 
  char  cChar
)
{
  unsigned32              pNS16550;
  unsigned char           ucLineStatus;
  int                     iTimeout;
  getRegister_f           getReg;
  setRegister_f           setReg;

  pNS16550 = Console_Port_Tbl[minor].ulCtrlPort1;
  getReg   = Console_Port_Tbl[minor].getRegister;
  setReg   = Console_Port_Tbl[minor].setRegister;

  /*
   * wait for transmitter holding register to be empty
   */
  iTimeout=1000;
  ucLineStatus = (*getReg)(pNS16550, NS16550_LINE_STATUS);
  while ((ucLineStatus & SP_LSR_THOLD) == 0) {
    /*
     * Yield while we wait
     */
#if 0
     if(_System_state_Is_up(_System_state_Get())) {
       rtems_task_wake_after(RTEMS_YIELD_PROCESSOR);
     }
#endif
     ucLineStatus = (*getReg)(pNS16550, NS16550_LINE_STATUS);
     if(!--iTimeout) {
       break;
     }
  }

  /*
   * transmit character
   */
  (*setReg)(pNS16550, NS16550_TRANSMIT_BUFFER, cChar);
}

/*
 * These routines provide control of the RTS and DTR lines
 */

/*
 *  ns16550_assert_RTS
 */

NS16550_STATIC int ns16550_assert_RTS(int minor)
{
  unsigned32              pNS16550;
  unsigned32              Irql;
  ns16550_context        *pns16550Context;
  setRegister_f           setReg;

  pns16550Context=(ns16550_context *) Console_Port_Data[minor].pDeviceContext;

  pNS16550 = Console_Port_Tbl[minor].ulCtrlPort1;
  setReg   = Console_Port_Tbl[minor].setRegister;

  /*
   * Assert RTS
   */
  rtems_interrupt_disable(Irql);
  pns16550Context->ucModemCtrl|=SP_MODEM_RTS;
  (*setReg)(pNS16550, NS16550_MODEM_CONTROL, pns16550Context->ucModemCtrl);
  rtems_interrupt_enable(Irql);
  return 0;
}

/*
 *  ns16550_negate_RTS
 */

NS16550_STATIC int ns16550_negate_RTS(int minor)
{
  unsigned32              pNS16550;
  unsigned32              Irql;
  ns16550_context        *pns16550Context;
  setRegister_f           setReg;

  pns16550Context=(ns16550_context *) Console_Port_Data[minor].pDeviceContext;

  pNS16550 = Console_Port_Tbl[minor].ulCtrlPort1;
  setReg   = Console_Port_Tbl[minor].setRegister;

  /*
   * Negate RTS
   */
  rtems_interrupt_disable(Irql);
  pns16550Context->ucModemCtrl&=~SP_MODEM_RTS;
  (*setReg)(pNS16550, NS16550_MODEM_CONTROL, pns16550Context->ucModemCtrl);
  rtems_interrupt_enable(Irql);
  return 0;
}

/*
 * These flow control routines utilise a connection from the local DTR
 * line to the remote CTS line
 */

/*
 *  ns16550_assert_DTR
 */

NS16550_STATIC int ns16550_assert_DTR(int minor)
{
  unsigned32              pNS16550;
  unsigned32              Irql;
  ns16550_context        *pns16550Context;
  setRegister_f           setReg;

  pns16550Context=(ns16550_context *) Console_Port_Data[minor].pDeviceContext;

  pNS16550 = Console_Port_Tbl[minor].ulCtrlPort1;
  setReg   = Console_Port_Tbl[minor].setRegister;

  /*
   * Assert DTR
   */
  rtems_interrupt_disable(Irql);
  pns16550Context->ucModemCtrl|=SP_MODEM_DTR;
  (*setReg)(pNS16550, NS16550_MODEM_CONTROL, pns16550Context->ucModemCtrl);
  rtems_interrupt_enable(Irql);
  return 0;
}

/*
 *  ns16550_negate_DTR
 */

NS16550_STATIC int ns16550_negate_DTR(int minor)
{
  unsigned32              pNS16550;
  unsigned32              Irql;
  ns16550_context        *pns16550Context;
  setRegister_f           setReg;

  pns16550Context=(ns16550_context *) Console_Port_Data[minor].pDeviceContext;

  pNS16550 = Console_Port_Tbl[minor].ulCtrlPort1;
  setReg   = Console_Port_Tbl[minor].setRegister;

  /*
   * Negate DTR
   */
  rtems_interrupt_disable(Irql);
  pns16550Context->ucModemCtrl&=~SP_MODEM_DTR;
  (*setReg)(pNS16550, NS16550_MODEM_CONTROL,pns16550Context->ucModemCtrl);
  rtems_interrupt_enable(Irql);
  return 0;