source: mainline/kernel/arch/mips32/src/drivers/serial.c@ 0c33687a

/*
 * Copyright (c) 2005 Ondrej Palkovsky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup mips32
 * @{
 */
/** @file
 */

#include <interrupt.h>
#include <arch/cp0.h>
#include <arch/drivers/serial.h>
#include <console/chardev.h>
#include <console/console.h>

#define SERIAL_IRQ 2

static irq_t serial_irq;
static chardev_t console;
static serial_t sconf[SERIAL_MAX];
static bool kb_enabled;

static void serial_write(chardev_t *d, const char ch, bool silent)
{
        if (!silent) {
                serial_t *sd = (serial_t *)d->data;
                
                if (ch == '\n')
                        serial_write(d, '\r', false);
                
                /* Wait until transmit buffer empty */
                while (!(SERIAL_READ_LSR(sd->port) & (1 << TRANSMIT_EMPTY_BIT)));
                SERIAL_WRITE(sd->port, ch);
        }
}

static void serial_enable(chardev_t *d)
{
        kb_enabled = true;
}

static void serial_disable(chardev_t *d)
{
        kb_enabled = false;
}

int serial_init(void)
{
        int i = 0;
        if (SERIAL_READ_LSR(SERIAL_COM1) == 0x60) {
                sconf[i].port = SERIAL_COM1;
                sconf[i].irq = SERIAL_COM1_IRQ;
                /* Enable interrupt on available data */
                i++;
        }
        return i;
}

/** Read character from serial port, wait until available */
static char serial_do_read(chardev_t *dev)
{
        serial_t *sd = (serial_t *)dev->data;
        char ch;

        while (!(SERIAL_READ_LSR(sd->port) & 1))
                ;
        ch = SERIAL_READ(sd->port);

        if (ch =='\r')
                ch = '\n';
        return ch;
}

static void serial_handler(void)
{
        serial_t *sd = (serial_t *) console.data;
        char ch;

        if (!(SERIAL_READ_LSR(sd->port) & 1))
                return;
        ch = SERIAL_READ(sd->port);

        if (ch =='\r')
                ch = '\n';
        chardev_push_character(&console, ch);
}

/** Process keyboard interrupt. Does not work in simics? */
static void serial_irq_handler(irq_t *irq)
{
        serial_handler();
}

static irq_ownership_t serial_claim(irq_t *irq)
{
        return IRQ_ACCEPT;
}

static chardev_operations_t serial_ops = {
        .resume = serial_enable,
        .suspend = serial_disable,
        .write = serial_write,
        .read = serial_do_read
};

void serial_console(devno_t devno)
{
        serial_t *sd = &sconf[0];
        
        chardev_initialize("serial_console", &console, &serial_ops);
        console.data = sd;
        kb_enabled = true;
        
        irq_initialize(&serial_irq);
        serial_irq.devno = devno;
        serial_irq.inr = SERIAL_IRQ;
        serial_irq.claim = serial_claim;
        serial_irq.handler = serial_irq_handler;
        irq_register(&serial_irq);
        
        /* I don't know why, but the serial interrupts simply
           don't work on simics */
        virtual_timer_fnc = &serial_handler;
        
        stdin = &console;
        stdout = &console;
}

/** @}
 */