source: trunk/hal/x86_64/drivers/txt_rs232.c @ 633

/*
 * txt_rs232.c - RS232 driver implementation
 *
 * Copyright (c) 2017 Maxime Villard
 *
 * This file is part of ALMOS-MKH.
 *
 * ALMOS-MKH 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; version 2.0 of the License.
 *
 * ALMOS-MKH 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 ALMOS-MKH; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <dev_txt.h>
#include <chdev.h>
#include <txt_rs232.h>
#include <remote_spinlock.h>
#include <thread.h>
#include <hal_special.h>

#include <hal_internal.h> // XXX

void txt_rs232_init(chdev_t *chdev)
{
        chdev->cmd = &txt_rs232_cmd;
        chdev->isr = &txt_rs232_isr;

        // nothing to do
}

// Pour le write: tout en sync, ça part direct sur le VGA/série
// Pour le read: là on attend l'ISR
void txt_rs232_cmd(xptr_t th_xp)
{
        // get client thread cluster and local pointer
        cxy_t      th_cxy = GET_CXY( th_xp );
        thread_t * th_ptr = (thread_t *)GET_PTR( th_xp );

        // get command type and extended pointer on TXT device
        uint32_t type   =         hal_remote_l32 ( XPTR( th_cxy , &th_ptr->txt_cmd.type ) );
        xptr_t   dev_xp = (xptr_t)hal_remote_l64( XPTR( th_cxy , &th_ptr->txt_cmd.dev_xp ) );

        // get TXT device cluster and local pointer
        cxy_t     dev_cxy = GET_CXY( dev_xp );
        chdev_t * dev_ptr = (chdev_t *)GET_PTR( dev_xp );

        // get TTY channel index
        uint32_t   channel = hal_remote_l32( XPTR( dev_cxy , &dev_ptr->channel ) );

        // for now, only channel zero
        if (channel != 0) {
                x86_panic("should have been channel zero");
        }

        if (type == TXT_READ)              // descheduling strategy for calling thread
        {
                x86_panic("TXT_READ not handled");
        }
        else if (type == TXT_WRITE || type == TXT_SYNC_WRITE) // busy waiting strategy for calling thread
        {
                uint32_t   i;

                // get source buffer extended pointer & bytes count
                uint32_t count  = hal_remote_l32 ( XPTR( th_cxy , &th_ptr->txt_cmd.count ) );
                xptr_t   buf_xp = hal_remote_l64( XPTR( th_cxy , &th_ptr->txt_cmd.buf_xp ) );

                // loop on characters
                for (i = 0; i < count; i++)
                {
                        // get one byte from command buffer in client cluster
                        char byte = (char)hal_remote_lb( buf_xp + i );

                        // VGA output (for now)
                        x86_putc(byte);
                }
        }
}

void txt_rs232_isr(chdev_t *chdev)
{
        // Cette ISR est juste utile pour le clavier; on arrive ici quand une touche
        // est pressée
        x86_panic("txt_rs232_isr not handled");
}