uart.c

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

/*
 * This software is Copyright (C) 1998 by T.sqware - all rights limited
 * It is provided in to the public domain "as is", can be freely modified
 * as far as this copyight notice is kept unchanged, but does not imply
 * an endorsement by T.sqware of the product in which it is included.
 *
 *  $Id: uart.c,v 1.11 2002/07/16 22:30:11 joel Exp $
 */

#include <stdio.h>
#include <bsp.h>
#include <irq.h>
#include <uart.h>
#include <rtems/libio.h>
#include <rtems/termiostypes.h>
#include <termios.h>
#include <assert.h>

/*
 * Basic 16552 driver
 */

struct uart_data
{
  int ioMode;
  int hwFlow;
  unsigned int  ier;
  unsigned long baud;
  unsigned long databits;
  unsigned long parity;
  unsigned long stopbits;
};

static struct uart_data uart_data[2];

/* 
 * Macros to read/write register of uart, if configuration is
 * different just rewrite these macros
 */ 

static inline unsigned char
uread(int uart, unsigned int reg)
{
  register unsigned char val;

  if (uart == 0) {
    inport_byte(COM1_BASE_IO+reg, val);
  } else {
    inport_byte(COM2_BASE_IO+reg, val);
  }

  return val;
}

static inline void      
uwrite(int uart, int reg, unsigned int val)
{
  if (uart == 0) {
    outport_byte(COM1_BASE_IO+reg, val);
  } else {
    outport_byte(COM2_BASE_IO+reg, val);
  }
}

#ifdef UARTDEBUG
    static void
uartError(int uart)
{
  unsigned char uartStatus, dummy;

  uartStatus = uread(uart, LSR);
  dummy = uread(uart, RBR);

  if (uartStatus & OE)
    printk("********* Over run Error **********\n");
  if (uartStatus & PE)
    printk("********* Parity Error   **********\n");
  if (uartStatus & FE)
    printk("********* Framing Error  **********\n");
  if (uartStatus & BI)
    printk("********* Parity Error   **********\n");
  if (uartStatus & ERFIFO)
    printk("********* Error receive Fifo **********\n");

}
#else
inline void uartError(int uart)
{
  unsigned char uartStatus;
  
  uartStatus = uread(uart, LSR);
  uartStatus = uread(uart, RBR);
}
#endif

/* 
 * Uart initialization, it is hardcoded to 8 bit, no parity,
 * one stop bit, FIFO, things to be changed
 * are baud rate and nad hw flow control,
 * and longest rx fifo setting
 */
void
BSP_uart_init
(
  int uart,
  unsigned long baud,
  unsigned long databits,
  unsigned long parity,
  unsigned long stopbits,
  int hwFlow
)
{
  unsigned char tmp;
  
  /* Sanity check */
  assert(uart == BSP_UART_COM1 || uart == BSP_UART_COM2);
  
  switch(baud)
    {
    case 50:
    case 75:
    case 110:
    case 134:
    case 300:
    case 600:
    case 1200:
    case 2400:
    case 9600:
    case 19200:
    case 38400:
    case 57600:
    case 115200:
      break;
    default:
      assert(0);
      return;
    }
  
  /* Set DLAB bit to 1 */
  uwrite(uart, LCR, DLAB);
  
  /* Set baud rate */
  uwrite(uart, DLL,  (BSPBaseBaud/baud) & 0xff); 
  uwrite(uart, DLM,  ((BSPBaseBaud/baud) >> 8) & 0xff); 

  /* 8-bit, no parity , 1 stop */
  uwrite(uart, LCR, databits | parity | stopbits);
  

  /* Set DTR, RTS and OUT2 high */
  uwrite(uart, MCR, DTR | RTS | OUT_2);

  /* Enable FIFO */
  uwrite(uart, FCR, FIFO_EN | XMIT_RESET | RCV_RESET | RECEIVE_FIFO_TRIGGER12); 

  /* Disable Interrupts */
  uwrite(uart, IER, 0);

  /* Read status to clear them */
  tmp = uread(uart, LSR);
  tmp = uread(uart, RBR);
  tmp = uread(uart, MSR);

  /* Remember state */
  uart_data[uart].baud       = baud;
  uart_data[uart].databits   = databits;
  uart_data[uart].parity     = parity;
  uart_data[uart].stopbits   = stopbits;
  uart_data[uart].hwFlow     = hwFlow;
  return;
}

/* 
 * Set baud
 */

void
BSP_uart_set_baud( 
  int uart,
  unsigned long baud
)
{
  /* Sanity check */
  assert(uart == BSP_UART_COM1 || uart == BSP_UART_COM2);

  BSP_uart_set_attributes( uart, baud, uart_data[uart].databits, 
    uart_data[uart].parity, uart_data[uart].stopbits );
}

/*
 *  Set all attributes
 */

void
BSP_uart_set_attributes
(
  int uart,
  unsigned long baud,
  unsigned long databits,
  unsigned long parity,
  unsigned long stopbits
)
{
  unsigned char mcr, ier;

  /* Sanity check */
  assert(uart == BSP_UART_COM1 || uart == BSP_UART_COM2);
  
  /* 
   * This function may be called whenever TERMIOS parameters
   * are changed, so we have to make sure that baud change is 
   * indeed required
   */

  if( (baud     == uart_data[uart].baud)     &&
      (databits == uart_data[uart].databits) &&
      (parity   == uart_data[uart].parity)   &&
      (stopbits == uart_data[uart].stopbits) )
    {
      return;
    }

  mcr = uread(uart, MCR);
  ier = uread(uart, IER);

  BSP_uart_init(uart, baud, databits, parity, stopbits, uart_data[uart].hwFlow);

  uwrite(uart, MCR, mcr);
  uwrite(uart, IER, ier);
  
  return;
}

/*
 * Enable/disable interrupts 
 */
void 
BSP_uart_intr_ctrl(int uart, int cmd)
{
  int iStatus = (int)INTERRUPT_DISABLE;

  assert(uart == BSP_UART_COM1 || uart == BSP_UART_COM2);

  switch(cmd)
    {
    case BSP_UART_INTR_CTRL_ENABLE:
      iStatus |= (RECEIVE_ENABLE | RECEIVER_LINE_ST_ENABLE | TRANSMIT_ENABLE);
      if ( uart_data[uart].hwFlow ) {
        iStatus |= MODEM_ENABLE;
      }
      break;
    case BSP_UART_INTR_CTRL_TERMIOS:
      iStatus |= (RECEIVE_ENABLE | RECEIVER_LINE_ST_ENABLE);
      if ( uart_data[uart].hwFlow ) {
        iStatus |= MODEM_ENABLE;
      }
      break;
    case BSP_UART_INTR_CTRL_GDB:
      iStatus |= RECEIVE_ENABLE;
      break;
    }

  uart_data[uart].ier = iStatus;
  uwrite(uart, IER, iStatus);
 
  return;
}

void
BSP_uart_throttle(int uart)
{
  unsigned int mcr;
  
  assert(uart == BSP_UART_COM1 || uart == BSP_UART_COM2);

  if(!uart_data[uart].hwFlow)
    {
      /* Should not happen */
      assert(0);
      return;
    }
  mcr = uread (uart, MCR);
  /* RTS down */
  mcr &= ~RTS;
  uwrite(uart, MCR, mcr);

  return;
}

void
BSP_uart_unthrottle(int uart)
{
  unsigned int mcr;

  assert(uart == BSP_UART_COM1 || uart == BSP_UART_COM2);

  if(!uart_data[uart].hwFlow)
    {
      /* Should not happen */
      assert(0);
      return;
    }
  mcr = uread (uart, MCR);
  /* RTS up */
  mcr |= RTS;
  uwrite(uart, MCR, mcr);

  return;
}

/*
 * Status function, -1 if error
 * detected, 0 if no received chars available,
 * 1 if received char available, 2 if break
 * is detected, it will eat break and error 
 * chars. It ignores overruns - we cannot do 
 * anything about - it execpt count statistics
 * and we are not counting it.
 */
int 
BSP_uart_polled_status(int uart)
{
  unsigned char val;

  assert(uart == BSP_UART_COM1 || uart == BSP_UART_COM2);

  val = uread(uart, LSR);

  if(val & BI)
    {
      /* BREAK found, eat character */
      uread(uart, RBR);
      return BSP_UART_STATUS_BREAK;
    }

  if((val & (DR | OE | FE)) ==  1)
    {
      /* No error, character present */ 
      return BSP_UART_STATUS_CHAR;
    }

  if((val & (DR | OE | FE)) == 0)
    {
      /* Nothing */
      return BSP_UART_STATUS_NOCHAR;
    }

  /* 
   * Framing or parity error
   * eat character
   */
  uread(uart, RBR);
 
  return BSP_UART_STATUS_ERROR;
}


/*
 * Polled mode write function
 */
void 
BSP_uart_polled_write(int uart, int val)
{
  unsigned char val1;
  
  /* Sanity check */
  assert(uart == BSP_UART_COM1 || uart == BSP_UART_COM2);
  
  for(;;)
    {
      if((val1=uread(uart, LSR)) & THRE)
	{
	  break;
	}
    }

  if(uart_data[uart].hwFlow)
    {
      for(;;)
	{
	  if(uread(uart, MSR) & CTS)
	    {
	      break;
	    }
	}
    }

  uwrite(uart, THR, val & 0xff);
      
  /*
   * Wait for character to be transmitted.
   * This ensures that printk and printf play nicely together
   * when using the same serial port.
   * Yes, there's a performance hit here, but if we're doing
   * polled writes to a serial port we're probably not that
   * interested in efficiency anyway.....
   */
  for(;;)
    {
      if((val1=uread(uart, LSR)) & THRE)
      {
      break;
      }
    }

  return;
}

void
BSP_output_char_via_serial(int val)
{
  BSP_uart_polled_write(BSPConsolePort, val);
  if (val == '\n') BSP_uart_polled_write(BSPConsolePort,'\r');
}

/* 
 * Polled mode read function
 */
int 
BSP_uart_polled_read(int uart)
{
  unsigned char val;

  assert(uart == BSP_UART_COM1 || uart == BSP_UART_COM2);
  
  for(;;)
    {
      if(uread(uart, LSR) & DR)
	{
	  break;
	}
    }
  
  val = uread(uart, RBR);

  return (int)(val & 0xff);
}

unsigned 
BSP_poll_char_via_serial()
{
	return BSP_uart_polled_read(BSPConsolePort);
}


/* ================ Termios support  =================*/

static volatile int  termios_stopped_com1        = 0;
static volatile int  termios_tx_active_com1      = 0;
static void*	     termios_ttyp_com1           = NULL;
static char          termios_tx_hold_com1        = 0;
static volatile char termios_tx_hold_valid_com1  = 0;

static volatile int  termios_stopped_com2        = 0;
static volatile int  termios_tx_active_com2      = 0;
static void*	     termios_ttyp_com2           = NULL;
static char          termios_tx_hold_com2        = 0;
static volatile char termios_tx_hold_valid_com2  = 0;

static void ( *driver_input_handler_com1 )( void *,  char *, int ) = 0;
static void ( *driver_input_handler_com2 )( void *,  char *, int ) = 0;

/*
 * This routine sets the handler to handle the characters received
 * from the serial port.
 */
void uart_set_driver_handler( int port, void ( *handler )( void *,  char *, int ) )
{
  switch( port )
  {
    case BSP_UART_COM1:
     driver_input_handler_com1 = handler;
     break;

    case BSP_UART_COM2:
     driver_input_handler_com2 = handler;
     break;
  }
}


/*
 * Set channel parameters 
 */
void
BSP_uart_termios_set(int uart, void *ttyp)
{
  struct rtems_termios_tty *p = (struct rtems_termios_tty *)ttyp;
  unsigned char val;
  assert(uart == BSP_UART_COM1 || uart == BSP_UART_COM2);
  
  if(uart == BSP_UART_COM1)
    {
      uart_data[uart].ioMode = p->device.outputUsesInterrupts;
      if(uart_data[uart].hwFlow)
	{
	  val = uread(uart, MSR);

	  termios_stopped_com1   = (val & CTS) ? 0 : 1;
	}
      else
	{