uart.c

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

	  termios_stopped_com1 = 0;
	}
      termios_tx_active_com1      = 0;
      termios_ttyp_com1           = ttyp;
      termios_tx_hold_com1        = 0; 
      termios_tx_hold_valid_com1  = 0;
    }
  else
    {
      uart_data[uart].ioMode = p->device.outputUsesInterrupts;
      if(uart_data[uart].hwFlow)
	{
	  val = uread(uart, MSR);

	  termios_stopped_com2   = (val & CTS) ? 0 : 1;
	}
      else
	{
	  termios_stopped_com2 = 0;
	}
      termios_tx_active_com2      = 0;
      termios_ttyp_com2           = ttyp;
      termios_tx_hold_com2        = 0; 
      termios_tx_hold_valid_com2  = 0;
    }

  return;
}

int
BSP_uart_termios_read_com1(int uart)
{
  int     off = (int)0;
  char    buf[40];

  /* read bytes */
  while (( off < sizeof(buf) ) && ( uread(BSP_UART_COM1, LSR) & DR )) {
    buf[off++] = uread(BSP_UART_COM1, RBR);
  }

  /* write out data */
  if ( off > 0 ) {
    rtems_termios_enqueue_raw_characters(termios_ttyp_com1, buf, off);
  }

  /* enable receive interrupts */
  uart_data[BSP_UART_COM1].ier |= (RECEIVE_ENABLE | RECEIVER_LINE_ST_ENABLE);
  uwrite(BSP_UART_COM1, IER, uart_data[BSP_UART_COM1].ier);

  return ( EOF );
}

int
BSP_uart_termios_read_com2(int uart)
{
  int     off = (int)0;
  char    buf[40];

  /* read current byte */
  while (( off < sizeof(buf) ) && ( uread(BSP_UART_COM2, LSR) & DR )) {
    buf[off++] = uread(BSP_UART_COM2, RBR);
  }

  /* write out data */
  if ( off > 0 ) {
    rtems_termios_enqueue_raw_characters(termios_ttyp_com2, buf, off);
  }

  /* enable receive interrupts */
  uart_data[BSP_UART_COM2].ier |= (RECEIVE_ENABLE | RECEIVER_LINE_ST_ENABLE);
  uwrite(BSP_UART_COM2, IER, uart_data[BSP_UART_COM2].ier);

  return ( EOF );
}

int
BSP_uart_termios_write_com1(int minor, const char *buf, int len)
{
  assert(buf != NULL);

  if(len <= 0)
    {
      return 0;
    }

  /* If there TX buffer is busy - something is royally screwed up */
  assert((uread(BSP_UART_COM1, LSR) & THRE) != 0);

  if(termios_stopped_com1)
    {
      /* CTS low */
      termios_tx_hold_com1       = *buf;
      termios_tx_hold_valid_com1 = 1;
      return 0;
    }

  /* Write character */
  uwrite(BSP_UART_COM1, THR, *buf & 0xff);

  /* Enable interrupts if necessary */
  if ( !termios_tx_active_com1 ) {
    termios_tx_active_com1 = 1;
    uart_data[BSP_UART_COM1].ier |= TRANSMIT_ENABLE;
    uwrite(BSP_UART_COM1, IER, uart_data[BSP_UART_COM1].ier);
  }

  return 0;
}

int
BSP_uart_termios_write_com2(int minor, const char *buf, int len)
{
  assert(buf != NULL);

  if(len <= 0)
    {
      return 0;
    }


  /* If there TX buffer is busy - something is royally screwed up */
  assert((uread(BSP_UART_COM2, LSR) & THRE) != 0);

  if(termios_stopped_com2)
    {
      /* CTS low */
      termios_tx_hold_com2       = *buf;
      termios_tx_hold_valid_com2 = 1;
      return 0;
    }

  /* Write character */
  uwrite(BSP_UART_COM2, THR, *buf & 0xff);

  /* Enable interrupts if necessary */
  if ( !termios_tx_active_com2 ) {
    termios_tx_active_com2 = 1;
    uart_data[BSP_UART_COM2].ier |= TRANSMIT_ENABLE;
    uwrite(BSP_UART_COM2, IER, uart_data[BSP_UART_COM2].ier);
  }

  return 0;
}


void
BSP_uart_termios_isr_com1(void)
{
  unsigned char buf[40];
  unsigned char val;
  int      off, ret, vect;

  off = 0;

  for(;;)
    {
      vect = uread(BSP_UART_COM1, IIR) & 0xf;
      
      switch(vect)
	{
	case MODEM_STATUS :
	  val = uread(BSP_UART_COM1, MSR);
	  if(uart_data[BSP_UART_COM1].hwFlow)
	    {
	      if(val & CTS)
		{
		  /* CTS high */
		  termios_stopped_com1 = 0;
		  if(termios_tx_hold_valid_com1)
		    {
		      termios_tx_hold_valid_com1 = 0;
		      BSP_uart_termios_write_com1(0, &termios_tx_hold_com1,
						    1);
		    }
		}
	      else
		{
		  /* CTS low */
		  termios_stopped_com1 = 1;
		}
	    }
	  break;
	case NO_MORE_INTR :
	  /* No more interrupts */
	  if(off != 0)
	    {
	      /* Update rx buffer */
         if( driver_input_handler_com1 )
         {
             driver_input_handler_com1( termios_ttyp_com1, (char *)buf, off );
         } 
         else
         {
            /* Update rx buffer */
	         rtems_termios_enqueue_raw_characters(termios_ttyp_com1, (char *)buf, off );
         }
	    }
	  return;
	case TRANSMITTER_HODING_REGISTER_EMPTY :
	  /* 
	   * TX holding empty: we have to disable these interrupts 
	   * if there is nothing more to send. 
	   */

	  /* If nothing else to send disable interrupts */
	  ret = rtems_termios_dequeue_characters(termios_ttyp_com1, 1);
          if ( ret == 0 ) {
            termios_tx_active_com1 = 0;
            uart_data[BSP_UART_COM1].ier &= ~(TRANSMIT_ENABLE);
            uwrite(BSP_UART_COM1, IER, uart_data[BSP_UART_COM1].ier);
          }
	  break;
	case RECEIVER_DATA_AVAIL :
	case CHARACTER_TIMEOUT_INDICATION:
          if ( uart_data[BSP_UART_COM1].ioMode == TERMIOS_TASK_DRIVEN ) {
            /* ensure interrupts are enabled */
            if ( uart_data[BSP_UART_COM1].ier & RECEIVE_ENABLE ) {
              /* disable interrupts and notify termios */
              uart_data[BSP_UART_COM1].ier &= ~(RECEIVE_ENABLE | RECEIVER_LINE_ST_ENABLE);
              uwrite(BSP_UART_COM1, IER, uart_data[BSP_UART_COM1].ier);
              rtems_termios_rxirq_occured(termios_ttyp_com1);
            }
          }
          else {
	    /* RX data ready */
	    assert(off < sizeof(buf));
	    buf[off++] = uread(BSP_UART_COM1, RBR);
          }
	  break;
	case RECEIVER_ERROR:
	  /* RX error: eat character */
	   uartError(BSP_UART_COM1);
	  break;
	default:
	  /* Should not happen */
	  assert(0);
	  return;
	}
    }
}
	  
void
BSP_uart_termios_isr_com2()
{
  unsigned char buf[40];
  unsigned char val;
  int      off, ret, vect;

  off = 0;

  for(;;)
    {
      vect = uread(BSP_UART_COM2, IIR) & 0xf;
      
      switch(vect)
	{
	case MODEM_STATUS :
	  val = uread(BSP_UART_COM2, MSR);
	  if(uart_data[BSP_UART_COM2].hwFlow)
	    {
	      if(val & CTS)
		{
		  /* CTS high */
		  termios_stopped_com2 = 0;
		  if(termios_tx_hold_valid_com2)
		    {
		      termios_tx_hold_valid_com2 = 0;
		      BSP_uart_termios_write_com2(0, &termios_tx_hold_com2,
						    1);
		    }
		}
	      else
		{
		  /* CTS low */
		  termios_stopped_com2 = 1;
		}
	    }
	  break;
	case NO_MORE_INTR :
	  /* No more interrupts */
	  if(off != 0)
	    {
	      /* Update rx buffer */
         if( driver_input_handler_com2 )
         {
             driver_input_handler_com2( termios_ttyp_com2, (char *)buf, off );
         } 
         else
         {
	        rtems_termios_enqueue_raw_characters(termios_ttyp_com2, (char *)buf, off);
         }
	    }
	  return;
	case TRANSMITTER_HODING_REGISTER_EMPTY :
	  /* 
	   * TX holding empty: we have to disable these interrupts 
	   * if there is nothing more to send.
	   */

	  /* If nothing else to send disable interrupts */
	  ret = rtems_termios_dequeue_characters(termios_ttyp_com2, 1);
          if ( ret == 0 ) {
            termios_tx_active_com2 = 0;
            uart_data[BSP_UART_COM2].ier &= ~(TRANSMIT_ENABLE);
            uwrite(BSP_UART_COM2, IER, uart_data[BSP_UART_COM2].ier);
          }
	  break;
	case RECEIVER_DATA_AVAIL :
	case CHARACTER_TIMEOUT_INDICATION:
          if ( uart_data[BSP_UART_COM2].ioMode == TERMIOS_TASK_DRIVEN ) {
            /* ensure interrupts are enabled */
            if ( uart_data[BSP_UART_COM2].ier & RECEIVE_ENABLE ) {
              /* disable interrupts and notify termios */
              uart_data[BSP_UART_COM2].ier &= ~(RECEIVE_ENABLE | RECEIVER_LINE_ST_ENABLE);
              uwrite(BSP_UART_COM2, IER, uart_data[BSP_UART_COM2].ier);
              rtems_termios_rxirq_occured(termios_ttyp_com2);
            }
          }
          else {
	    /* RX data ready */
	    assert(off < sizeof(buf));
	    buf[off++] = uread(BSP_UART_COM2, RBR);
          }
	  break;
	case RECEIVER_ERROR:
	  /* RX error: eat character */
	   uartError(BSP_UART_COM2);
	  break;
	default:
	  /* Should not happen */
	  assert(0);
	  return;
	}
    }
}
	  
  
/* ================= GDB support     ===================*/ 
static int sav[4] __attribute__ ((unused));

/*
 * Interrupt service routine for COM1 - all, 
 * it does it check whether ^C is received
 * if yes it will flip TF bit before returning
 * Note: it should be installed as raw interrupt
 * handler
 */

asm (".p2align 4");
asm (".text");
asm (".globl BSP_uart_dbgisr_com1");
asm ("BSP_uart_dbgisr_com1:");
asm ("    movl %eax, sav");          /* Save eax */
asm ("    movl %ebx, sav + 4");      /* Save ebx */
asm ("    movl %edx, sav + 8");      /* Save edx */

asm ("    movl $0, %ebx");           /* Clear flag */

/* 
 * We know that only receive related interrupts
 * are available, eat chars
 */
asm ("uart_dbgisr_com1_1:");
asm ("    movw $0x3FD, %dx");
asm ("    inb  %dx, %al"); /* Read LSR */
asm ("    andb $1, %al");
asm ("    cmpb $0, %al");
asm ("    je   uart_dbgisr_com1_2");
asm ("    movw $0x3F8, %dx");
asm ("    inb  %dx, %al");    /* Get input character */
asm ("    cmpb $3, %al");
asm ("    jne  uart_dbgisr_com1_1");

/* ^C received, set flag */ 
asm ("    movl $1, %ebx");
asm ("    jmp uart_dbgisr_com1_1");

/* All chars read */
asm ("uart_dbgisr_com1_2:");

/* If flag is set we have to tweak TF */
asm ("   cmpl $0, %ebx");
asm ("   je   uart_dbgisr_com1_3");

/* Flag is set */
asm ("   movl sav+4, %ebx");     /* Restore ebx */
asm ("   movl sav+8, %edx");     /* Restore edx */

/* Set TF bit */
asm ("   popl  %eax");           /* Pop eip */
asm ("   movl  %eax, sav + 4");  /* Save it */
asm ("   popl  %eax");           /* Pop cs */
asm ("   movl  %eax, sav + 8");  /* Save it */
asm ("   popl  %eax");           /* Pop flags */
asm ("   orl   $0x100, %eax");   /* Modify it */
asm ("   pushl %eax");           /* Push it back */
asm ("   movl  sav+8, %eax");    /* Put back cs */
asm ("   pushl %eax");
asm ("   movl  sav+4, %eax");    /* Put back eip */
asm ("   pushl %eax");

/* Acknowledge IRQ */
asm ("   movb  $0x20, %al");
asm ("   outb  %al, $0x20");
asm ("   movl  sav, %eax");      /* Restore eax */
asm ("   iret");                 /* Done */

/* Flag is not set */
asm("uart_dbgisr_com1_3:");
asm ("   movl sav+4, %ebx");     /* Restore ebx */
asm ("   movl sav+8, %edx");     /* Restore edx */

/* Acknowledge irq */
asm ("   movb  $0x20, %al");
asm ("   outb  %al, $0x20");
asm ("   movl  sav, %eax");      /* Restore eax */
asm ("   iret");                 /* Done */


/*
 * Interrupt service routine for COM2 - all, 
 * it does it check whether ^C is received
 * if yes it will flip TF bit before returning
 * Note: it has to be installed as raw interrupt 
 * handler
 */
asm (".p2align 4");
asm (".text");
asm (".globl BSP_uart_dbgisr_com2");
asm ("BSP_uart_dbgisr_com2:");
asm ("    movl %eax, sav");          /* Save eax */
asm ("    movl %ebx, sav + 4");      /* Save ebx */
asm ("    movl %edx, sav + 8");      /* Save edx */

asm ("    movl $0, %ebx");           /* Clear flag */

/* 
 * We know that only receive related interrupts
 * are available, eat chars
 */
asm ("uart_dbgisr_com2_1:");
asm ("    movw $0x2FD, %dx");
asm ("    inb  %dx, %al"); /* Read LSR */
asm ("    andb $1, %al");
asm ("    cmpb $0, %al");
asm ("    je   uart_dbgisr_com2_2");
asm ("    movw $0x2F8, %dx");
asm ("    inb  %dx, %al");    /* Get input character */
asm ("    cmpb $3, %al");
asm ("    jne  uart_dbgisr_com2_1");

/* ^C received, set flag */ 
asm ("    movl $1, %ebx");
asm ("    jmp uart_dbgisr_com2_1");

/* All chars read */
asm ("uart_dbgisr_com2_2:");

/* If flag is set we have to tweak TF */
asm ("   cmpl $0, %ebx");
asm ("   je   uart_dbgisr_com2_3");

/* Flag is set */
asm ("   movl sav+4, %ebx");     /* Restore ebx */
asm ("   movl sav+8, %edx");     /* Restore edx */

/* Set TF bit */
asm ("   popl  %eax");           /* Pop eip */
asm ("   movl  %eax, sav + 4");  /* Save it */
asm ("   popl  %eax");           /* Pop cs */
asm ("   movl  %eax, sav + 8");  /* Save it */
asm ("   popl  %eax");           /* Pop flags */
asm ("   orl   $0x100, %eax");   /* Modify it */
asm ("   pushl %eax");           /* Push it back */
asm ("   movl  sav+8, %eax");    /* Put back cs */
asm ("   pushl %eax");
asm ("   movl  sav+4, %eax");    /* Put back eip */
asm ("   pushl %eax");

/* Acknowledge IRQ */
asm ("   movb  $0x20, %al");
asm ("   outb  %al, $0x20");
asm ("   movl  sav, %eax");      /* Restore eax */
asm ("   iret");                 /* Done */

/* Flag is not set */
asm("uart_dbgisr_com2_3:");
asm ("   movl sav+4, %ebx");     /* Restore ebx */
asm ("   movl sav+8, %edx");     /* Restore edx */

/* Acknowledge irq */
asm ("   movb  $0x20, %al");
asm ("   outb  %al, $0x20");
asm ("   movl  sav, %eax");      /* Restore eax */
asm ("   iret");                 /* Done */