/*
 * dev_txt.c - TXT (Text Terminal) generic device API implementation.
 *
 * Author  Alain Greiner    (2016)
 *
 * Copyright (c) UPMC Sorbonne Universites
 *
 * This file is part of ALMOS-MK
 *
 * 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-kernel; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <hal_types.h>
#include <hal_special.h>
#include <hal_remote.h>
#include <hal_drivers.h>
#include <thread.h>
#include <rpc.h>
#include <printk.h>
#include <dev_txt.h>

/////////////////////////////////////////////////////////////////////////////////////////
// Extern global variables
/////////////////////////////////////////////////////////////////////////////////////////

extern chdev_directory_t  chdev_dir;         // allocated in kernel_init.c

//////////////////////////////////
void dev_txt_init( chdev_t * txt )
{
    // For all TXT channels other than the TXT0 (kernel terminal), 
    // the PIC chdev must be initialized before the TXT chdev, because
    // the TXT chdev initialization requires the routing of an external IRQ

    xptr_t    pic_xp  = chdev_dir.pic;
    uint32_t  channel = txt->channel;
    uint32_t  impl    = txt->impl;

    assert( (pic_xp != XPTR_NULL) || (channel == 0) , __FUNCTION__ , 
            "PIC not initialised before TXT" );

    // set chdev name
    snprintf( txt->name , 16 , "txt_%d" , channel );

    // call driver init function
    hal_drivers_txt_init(txt, impl);

    // no server thread and no IRQ routing for TXT0 and IMPL_TXT_RS2 (multiplexed
    // in software, not hardware)
    if( channel != 0 && impl != IMPL_TXT_RS2 )
    {
        // select a core to execute the TXT server thread
        lid_t lid = cluster_select_local_core();

        // bind TXT IRQ to the selected core
        dev_pic_bind_irq( lid , txt );

        // enable TXT IRQ
        dev_pic_enable_irq( lid , XPTR( local_cxy , txt ) );

        // create server thread
        thread_t * new_thread;
        error_t    error;

        error = thread_kernel_create( &new_thread,
                                      THREAD_DEV,
                                      &chdev_sequencial_server,
                                      txt,
                                      lid );

        assert( (error == 0) , __FUNCTION__ , "cannot create server thread" );

        // set "server" field in chdev descriptor
        txt->server = new_thread;

        // start server thread
        thread_unblock( XPTR( local_cxy , new_thread ) , THREAD_BLOCKED_GLOBAL );
    }
}

//////////////////////////////////////////////////////////////////////////////////
// This static function is called by dev_txt_read(), dev_txt_write() functions.
////////////////////////////////////i/////////////////////////////////////////////
static error_t dev_txt_access( uint32_t   type,
                               uint32_t   channel,
                               char     * buffer,
                               uint32_t   count )
{
    thread_t * this = CURRENT_THREAD;

    txt_dmsg("\n[INFO] in %s : thread %x in process %x enters\n",
                 __FUNCTION__ , this->trdid , this->process->pid );

    // check channel argument
    assert( (channel < CONFIG_MAX_TXT_CHANNELS) , __FUNCTION__ , "illegal channel index" );

    // get extended pointer on remote TXT chdev descriptor
    xptr_t  dev_xp = chdev_dir.txt[channel];

    assert( (dev_xp != XPTR_NULL) , __FUNCTION__ , "undefined TXT chdev descriptor" );

    // register command in calling thread descriptor
    this->command.txt.dev_xp  = dev_xp;
    this->command.txt.type    = type;
    this->command.txt.buf_xp  = XPTR( local_cxy , buffer );
    this->command.txt.count   = count;

    // register client thread in waiting queue, activate server thread
    // block client thread on THREAD_BLOCKED_IO and deschedule.
    // it is re-activated by the ISR signaling IO operation completion.
    chdev_register_command( dev_xp , this );

    txt_dmsg("\n[INFO] in %s : thread %x in process %x completes / error = %d\n",
             __FUNCTION__ , this->trdid , this->process->pid , this->command.txt.error );

    // return I/O operation status from calling thread descriptor
    return this->command.txt.error;
}

/////////////////////////////////////////
error_t dev_txt_write( uint32_t   channel,
                       char     * buffer,
                       uint32_t   count )
{
    return dev_txt_access( TXT_WRITE , channel , buffer , count );
}

/////////////////////////////////////////
error_t dev_txt_read( uint32_t   channel,
                      char     * buffer )
{
    return dev_txt_access( TXT_READ , channel , buffer , 1 );
}

///////////////////////////////////////////////
error_t dev_txt_sync_write( uint32_t   channel,
                            char     * buffer,
                            uint32_t   count )
{
    // get pointer on calling thread
    thread_t * this = CURRENT_THREAD;

    // get extended pointer on TXT[0] chdev
    xptr_t  dev_xp = chdev_dir.txt[channel];

    assert( (dev_xp != XPTR_NULL) , __FUNCTION__ , "undefined TXT0 chdev descriptor" );

    // register command in calling thread
    this->command.txt.dev_xp  = dev_xp;
    this->command.txt.type    = TXT_SYNC_WRITE;
    this->command.txt.buf_xp  = XPTR( local_cxy , buffer );
    this->command.txt.count   = count;

    // get driver command function
    cxy_t       dev_cxy = GET_CXY( dev_xp );
    chdev_t   * dev_ptr = (chdev_t *)GET_PTR( dev_xp );
    dev_cmd_t * cmd = (dev_cmd_t *)hal_remote_lpt( XPTR( dev_cxy , &dev_ptr->cmd ) );

    // call directly driver command
    cmd( XPTR( local_cxy , this ) );

    // return I/O operation status from calling thread descriptor
    return this->command.txt.error;
}