Logo Search packages:      
Sourcecode: linux version File versions  Download package

ns16550.c

/*
 * COM1 NS16550 support
 */

#include <linux/types.h>
#include <linux/serial.h>
#include <linux/serial_reg.h>
#include <asm/serial.h>

#if defined(CONFIG_XILINX_VIRTEX)
#include <platforms/4xx/xparameters/xparameters.h>
#endif
#include "nonstdio.h"
#include "serial.h"

#define SERIAL_BAUD     9600

extern unsigned long ISA_io;

static struct serial_state rs_table[RS_TABLE_SIZE] = {
      SERIAL_PORT_DFNS  /* Defined in <asm/serial.h> */
};

static int shift;

unsigned long serial_init(int chan, void *ignored)
{
      unsigned long com_port, base_baud;
      unsigned char lcr, dlm;

      /* We need to find out which type io we're expecting.  If it's
       * 'SERIAL_IO_PORT', we get an offset from the isa_io_base.
       * If it's 'SERIAL_IO_MEM', we can the exact location.  -- Tom */
      switch (rs_table[chan].io_type) {
            case SERIAL_IO_PORT:
                  com_port = rs_table[chan].port;
                  break;
            case SERIAL_IO_MEM:
                  com_port = (unsigned long)rs_table[chan].iomem_base;
                  break;
            default:
                  /* We can't deal with it. */
                  return -1;
      }

      /* How far apart the registers are. */
      shift = rs_table[chan].iomem_reg_shift;
      /* Base baud.. */
      base_baud = rs_table[chan].baud_base;
      
      /* save the LCR */
      lcr = inb(com_port + (UART_LCR << shift));
      /* Access baud rate */
      outb(com_port + (UART_LCR << shift), 0x80);
      dlm = inb(com_port + (UART_DLM << shift));
      /*
       * Test if serial port is unconfigured.
       * We assume that no-one uses less than 110 baud or
       * less than 7 bits per character these days.
       *  -- paulus.
       */

      if ((dlm <= 4) && (lcr & 2))
            /* port is configured, put the old LCR back */
            outb(com_port + (UART_LCR << shift), lcr);
      else {
            /* Input clock. */
            outb(com_port + (UART_DLL << shift),
                 (base_baud / SERIAL_BAUD) & 0xFF);
            outb(com_port + (UART_DLM << shift),
                 (base_baud / SERIAL_BAUD) >> 8);
            /* 8 data, 1 stop, no parity */
            outb(com_port + (UART_LCR << shift), 0x03);
            /* RTS/DTR */
            outb(com_port + (UART_MCR << shift), 0x03);
      }
      /* Clear & enable FIFOs */
      outb(com_port + (UART_FCR << shift), 0x07);

      return (com_port);
}

void
serial_putc(unsigned long com_port, unsigned char c)
{
      while ((inb(com_port + (UART_LSR << shift)) & UART_LSR_THRE) == 0)
            ;
      outb(com_port, c);
}

unsigned char
serial_getc(unsigned long com_port)
{
      while ((inb(com_port + (UART_LSR << shift)) & UART_LSR_DR) == 0)
            ;
      return inb(com_port);
}

int
serial_tstc(unsigned long com_port)
{
      return ((inb(com_port + (UART_LSR << shift)) & UART_LSR_DR) != 0);
}

Generated by  Doxygen 1.6.0   Back to index