100 lines
2.3 KiB
C
100 lines
2.3 KiB
C
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/*
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* COM1 NS16550 support
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*/
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#include <linux/config.h>
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#include <linux/types.h>
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#include <linux/serial.h>
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#include <linux/serial_reg.h>
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#include <asm/serial.h>
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#include "nonstdio.h"
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#include "serial.h"
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#define SERIAL_BAUD 9600
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extern unsigned long ISA_io;
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static struct serial_state rs_table[RS_TABLE_SIZE] = {
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SERIAL_PORT_DFNS /* Defined in <asm/serial.h> */
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};
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static int shift;
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unsigned long serial_init(int chan, void *ignored)
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{
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unsigned long com_port;
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unsigned char lcr, dlm;
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/* We need to find out which type io we're expecting. If it's
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* 'SERIAL_IO_PORT', we get an offset from the isa_io_base.
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* If it's 'SERIAL_IO_MEM', we can the exact location. -- Tom */
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switch (rs_table[chan].io_type) {
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case SERIAL_IO_PORT:
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com_port = rs_table[chan].port;
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break;
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case SERIAL_IO_MEM:
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com_port = (unsigned long)rs_table[chan].iomem_base;
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break;
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default:
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/* We can't deal with it. */
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return -1;
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}
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/* How far apart the registers are. */
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shift = rs_table[chan].iomem_reg_shift;
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/* save the LCR */
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lcr = inb(com_port + (UART_LCR << shift));
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/* Access baud rate */
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outb(com_port + (UART_LCR << shift), 0x80);
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dlm = inb(com_port + (UART_DLM << shift));
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/*
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* Test if serial port is unconfigured.
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* We assume that no-one uses less than 110 baud or
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* less than 7 bits per character these days.
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* -- paulus.
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*/
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if ((dlm <= 4) && (lcr & 2))
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/* port is configured, put the old LCR back */
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outb(com_port + (UART_LCR << shift), lcr);
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else {
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/* Input clock. */
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outb(com_port + (UART_DLL << shift),
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(BASE_BAUD / SERIAL_BAUD) & 0xFF);
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outb(com_port + (UART_DLM << shift),
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(BASE_BAUD / SERIAL_BAUD) >> 8);
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/* 8 data, 1 stop, no parity */
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outb(com_port + (UART_LCR << shift), 0x03);
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/* RTS/DTR */
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outb(com_port + (UART_MCR << shift), 0x03);
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}
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/* Clear & enable FIFOs */
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outb(com_port + (UART_FCR << shift), 0x07);
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return (com_port);
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}
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void
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serial_putc(unsigned long com_port, unsigned char c)
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{
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while ((inb(com_port + (UART_LSR << shift)) & UART_LSR_THRE) == 0)
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;
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outb(com_port, c);
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}
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unsigned char
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serial_getc(unsigned long com_port)
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{
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while ((inb(com_port + (UART_LSR << shift)) & UART_LSR_DR) == 0)
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;
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return inb(com_port);
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}
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int
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serial_tstc(unsigned long com_port)
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{
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return ((inb(com_port + (UART_LSR << shift)) & UART_LSR_DR) != 0);
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}
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