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/* output-serial.c - A serial port output driver.
Copyright (C) 2003, 2008 Free Software Foundation, Inc.
Written by Daniel Wagner.
This file is part of the GNU Hurd.
The GNU Hurd is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2, or (at
your option) any later version.
The GNU Hurd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
#if HAVE_CONFIG_H
#include <config.h>
#endif
#include <sys/io.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <l4/ipc.h>
#include "output.h"
/* The base I/O ports for the serial device ports COM1 and COM2. */
#define UART1_BASE 0x3f8
#define UART2_BASE 0x2f8
/* The default base port. */
#define UART_BASE_DEFAULT UART1_BASE;
/* The data register. */
#define UART_DR (device->cookie + 0)
/* The interrupt enable and ID registers. */
#define UART_IER (device->cookie + 1)
#define UART_IIR (device->cookie + 2)
/* The line and modem control and status registers. */
#define UART_LCR (device->cookie + 3)
#define UART_MCR (device->cookie + 4)
#define UART_LSR (device->cookie + 5)
/* Data ready. */
#define UART_LSR_DR (1 << 0)
/* Empty transmitter holding register. */
#define UART_LSR_THRE (1 << 5)
#define UART_MSR (device->cookie + 6)
/* Baudrate divisor LSB and MSB registers. */
#define UART_LSB (device->cookie + 0)
#define UART_MSB (device->cookie + 1)
/* The default speed setting. */
#define UART_SPEED_MAX 115200
#define UART_SPEED_MIN 50
#define UART_SPEED_DEFAULT UART_SPEED_MAX
static void
serial_init (struct output_driver *device, const char *driver_cfg)
{
/* Twice the desired UART speed, to allow for .5 values. */
unsigned int uart_speed = 2 * UART_SPEED_DEFAULT;
unsigned int divider;
device->cookie = UART_BASE_DEFAULT;
if (driver_cfg)
{
char *cfg = strdupa (driver_cfg);
char *token = cfg;
bool done = false;
while (*cfg && *cfg != ',' )
cfg ++;
if (*cfg == 0)
done = true;
*cfg = 0;
while (token)
{
if (!strcmp (token, "uart1"))
device->cookie = UART1_BASE;
if (!strcmp (token, "uart2"))
device->cookie = UART2_BASE;
if (!strncmp (token, "speed=", 6))
{
char *tail;
unsigned long new_speed;
errno = 0;
new_speed = strtoul (&token[6], &tail, 0);
/* Allow .5 for speeds like 134.5. */
new_speed <<= 1;
if (tail[0] == '.' && tail[1] == '5')
{
new_speed++;
tail += 2;
}
if (!errno && !*tail
&& new_speed > UART_SPEED_MIN && new_speed < UART_SPEED_MAX)
uart_speed = new_speed;
}
if (done)
token = NULL;
else
{
while (*cfg && *cfg != ',' )
cfg ++;
if (*cfg == 0)
done = true;
*cfg = 0;
}
}
}
/* Parity bit. */
outb (0x80, UART_LCR);
/* FIXME: How long do we have to wait? */
l4_sleep (l4_time_period (L4_WORD_C (100000)));
/* Set baud rate. */
divider = (2 * UART_SPEED_MAX) / uart_speed;
outb ((divider >> 0) & 0xff, UART_LSB);
outb ((divider >> 8) & 0xff, UART_MSB);
/* Set 8,N,1. */
outb (0x03, UART_LCR);
/* Disable interrupts. */
outb (0x00, UART_IER);
/* Enable FIFOs. */
outb (0x07, UART_IIR);
/* Enable RX interrupts. */
outb (0x01, UART_IER);
inb (UART_IER);
inb (UART_IIR);
inb (UART_LCR);
inb (UART_MCR);
inb (UART_LSR);
inb (UART_MSR);
}
static void
serial_putchar (struct output_driver *device, int chr)
{
while (!(inb (UART_LSR) & UART_LSR_THRE))
;
outb (chr, UART_DR);
if (chr == '\n')
serial_putchar (device, '\r');
}
static int
serial_getchar (struct output_driver *device)
{
while (!((inb (UART_LSR)) & UART_LSR_DR))
;
return inb (UART_DR);
}
struct output_driver serial_output =
{
"serial",
serial_init,
0, /* deinit */
serial_putchar,
serial_getchar
};
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