///////////////////////////////////////////////////////////////////////////////////
// File     : sys_handler.c
// Date     : 01/04/2012
// Author   : alain greiner and joel porquet
// Copyright (c) UPMC-LIP6
///////////////////////////////////////////////////////////////////////////////////
// The sys_handler.c and sys_handler.h files are part of the GIET-VM nano-kernel.
// It define the syscall_vector[] (at the end of this file), as well as the 
// associated syscall handlers that are not related to peripherals.
// The syscall handlers for peripherals are defined in the drivers.c file.
///////////////////////////////////////////////////////////////////////////////////

#include <sys_handler.h>
#include <drivers.h>
#include <ctx_handler.h>
#include <common.h>
#include <giet_config.h>
#include <mapping_info.h>

////////////////////////////////////////////////////////////////////////////
//	Initialize the syscall vector with syscall handlers
////////////////////////////////////////////////////////////////////////////
const void *_syscall_vector[32] = {
    &_procid,           /* 0x00 */
    &_proctime,         /* 0x01 */
    &_tty_write,        /* 0x02 */
    &_tty_read,         /* 0x03 */
    &_timer_start,      /* 0x04 */
    &_timer_stop,       /* 0x05 */
    &_gcd_write,        /* 0x06 */
    &_gcd_read,         /* 0x07 */
    &_sys_ukn,          /* 0x08 */
    &_sys_ukn,          /* 0x09 */
    &_tty_read_irq,     /* 0x0A */
    &_sys_ukn,          /* 0x0B */
    &_sys_ukn,          /* 0x0C */
    &_ctx_switch,       /* 0x0D */
    &_exit,             /* 0x0E */
    &_procs_number,     /* 0x0F */
    &_fb_sync_write,    /* 0x10 */
    &_fb_sync_read,     /* 0x11 */
    &_fb_write,         /* 0x12 */
    &_fb_read,          /* 0x13 */
    &_fb_completed,     /* 0x14 */
    &_ioc_write,        /* 0x15 */
    &_ioc_read,         /* 0x16 */
    &_ioc_completed,    /* 0x17 */
    &_sys_ukn,          /* 0x18 */
    &_sys_ukn,          /* 0x19 */
    &_vobj_get_vbase,   /* 0x1A */
    &_sys_ukn,          /* 0x1B */
    &_sys_ukn,          /* 0x1C */
    &_sys_ukn,          /* 0x1D */
    &_sys_ukn,          /* 0x1E */
    &_sys_ukn,          /* 0x1F */
};

//////////////////////////////////////////////////////////////////////////////
// function executed in case of undefined syscall
//////////////////////////////////////////////////////////////////////////////
void _sys_ukn()
{
    unsigned int 	epc;
    asm volatile("mfc0 %0, $14" : "=r"(epc));

    _puts("\n\n!!! Undefined System Call !!!\n");
    _puts("\nEPC = ");
    _putw( epc );
    _exit();
}
////////////////////////////////////////////////////////////////////////////
// _exit()
// Task suicide... after printing a death message.
////////////////////////////////////////////////////////////////////////////
void _exit()
{
    unsigned int date    = _proctime();
    unsigned int proc_id = _procid();
    unsigned int task_id = _get_current_task_id();

     // print death message
    _get_lock(&_tty_put_lock);
    _puts("\n[GIET] Exit task ");
    _putd( task_id );
    _puts(" on processor ");
    _putd( proc_id );
    _puts(" at cycle ");
    _putd( date );
    _puts("\n\n");
    _release_lock(&_tty_put_lock);
    
    // goes to sleeping state
    _set_context_slot( task_id, CTX_RUN_ID, 0 );
    
    // deschedule
    _ctx_switch();
} 
//////////////////////////////////////////////////////////////////////////////
// _procid()
// Access CP0 and returns current processor's identifier.
// Max number or processors is 1024.
//////////////////////////////////////////////////////////////////////////////
unsigned int _procid()
{
    unsigned int ret;
    asm volatile("mfc0 %0, $15, 1" : "=r"(ret));
    return (ret & 0xFFF);
}
//////////////////////////////////////////////////////////////////////////////
// _proctime()
// Access CP0 and returns current processor's elapsed clock cycles since boot.
//////////////////////////////////////////////////////////////////////////////
unsigned int _proctime()
{
    unsigned int ret;
    asm volatile("mfc0 %0, $9" : "=r"(ret));
    return ret;
}
//////////////////////////////////////////////////////////////////////////////
// _procnumber()
// returns in buffer argument the number of processors in the cluster
// specified by the cluster_id argument.
//////////////////////////////////////////////////////////////////////////////
unsigned int _procs_number( unsigned int 	cluster_id,
                            unsigned int*	buffer)
{
    mapping_header_t* 	header  = (mapping_header_t*)&seg_mapping_base;
    mapping_cluster_t* 	cluster = _get_cluster_base( header );

    if ( cluster_id < header->clusters )
    {
        *buffer = cluster[cluster_id].procs;
        return 0;
    }
    else
    {
         return 1;
    }
}

/////////////////////////////////////////////////////////////////////////////
// _vobj_get_vbase()
// This function writes in vobj_buffer the virtual base address of a vobj 
// identified by the (vspace_name / vobj_name ) couple.
// The vobj_type argument is redundant, and for checking purpose.
// returns 0: success, else: failed.
/////////////////////////////////////////////////////////////////////////////
unsigned int _vobj_get_vbase( char*			vspace_name, 
                              char*			vobj_name,
                              unsigned int	vobj_type, 
                              unsigned int* vobj_vaddr )
{
    mapping_header_t* header = (mapping_header_t*)&seg_mapping_base;
    mapping_vspace_t* vspace = _get_vspace_base( header );
    mapping_vobj_t*    vobj  = _get_vobj_base( header );

    unsigned int    vspace_id;
    unsigned int    vobj_id;
        

    // scan vspaces 
    for ( vspace_id = 0 ; vspace_id < header->vspaces ; vspace_id++ )
    {
        if ( _strncmp( vspace[vspace_id].name, vspace_name, 31) == 0 )
        {
            // scan vobjs
            for( vobj_id = vspace[vspace_id].vobj_offset; 
                 vobj_id < (vspace[vspace_id].vobj_offset + vspace[vspace_id].vobjs); 
                 vobj_id++)
            {

                if ( _strncmp( vobj[vobj_id].name, vobj_name, 31) == 0 )
                {
                    if(vobj[vobj_id].type != vobj_type)
                        return -1;							//wrong type

                    *vobj_vaddr = (unsigned int)vobj[vobj_id].vaddr;
                    return 0;
                }
            } 
        }
    } 
    return -2;		//not found 
}