///////////////////////////////////////////////////////////////////////////////////
// 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 <tty_driver.h>
#include <tim_driver.h>
#include <ioc_driver.h>
#include <nic_driver.h>
#include <fbf_driver.h>
#include <ctx_handler.h>
#include <fat32.h>
#include <utils.h>
#include <giet_config.h>
#include <mapping_info.h>

////////////////////////////////////////////////////////////////////////////
//    Initialize the syscall vector with syscall handlers
// Note: This array must be synchronised with the define in file stdio.h
////////////////////////////////////////////////////////////////////////////
const void * _syscall_vector[64] = 
{
    &_get_procid,          /* 0x00 */
    &_get_proctime,        /* 0x01 */
    &_tty_write,           /* 0x02 */
    &_tty_read,            /* 0x03 */
    &_timer_start,         /* 0x04 */
    &_timer_stop,          /* 0x05 */
    &_sys_ukn,             /* 0x06 */
    &_sys_ukn,             /* 0x07 */
    &_heap_info,           /* 0x08 */
    &_local_task_id,       /* 0x09 */
    &_global_task_id,      /* 0x0A */ 
    &_fb_cma_init,         /* 0x0B */
    &_fb_cma_write,        /* 0x0C */
    &_fb_cma_stop,         /* 0x0D */
    &_task_exit,           /* 0x0E */
    &_procs_number,        /* 0x0F */

    &_fb_sync_write,       /* 0x10 */
    &_fb_sync_read,        /* 0x11 */
    &_thread_id,           /* 0x12 */
    &_tty_get_release_lock,/* 0x13 */
    &_sys_ukn,             /* 0x14 */
    &_sys_ukn,             /* 0x15 */ 
    &_sys_ukn,             /* 0x16 */
    &_sys_ukn,             /* 0x17 */
    &_sys_ukn,             /* 0x18 */   
    &_ctx_switch,          /* 0x19 */
    &_vobj_get_vbase,      /* 0x1A */
    &_sys_ukn,             /* 0x1B */
    &_nic_cma_start,       /* 0x1C */
    &_nic_cma_stop,        /* 0x1D */
    &_nic_sync_read,       /* 0x1E */
    &_nic_sync_write,      /* 0x1F */

    &_fat_user_open,       /* 0x20 */
    &_fat_user_read,       /* 0x21 */
    &_fat_user_write,      /* 0x22 */
    &_fat_user_lseek,      /* 0x23 */
    &_fat_fstat,           /* 0x24 */
    &_fat_close,           /* 0x25 */
    &_sys_ukn,             /* 0x26 */
    &_sys_ukn,             /* 0x27 */
    &_sys_ukn,             /* 0x28 */
    &_sys_ukn,             /* 0x29 */
    &_sys_ukn,             /* 0x2A */
    &_sys_ukn,             /* 0x2B */
    &_sys_ukn,             /* 0x2C */
    &_sys_ukn,             /* 0x2D */
    &_sys_ukn,             /* 0x2E */
    &_sys_ukn,             /* 0x2F */

    &_sys_ukn,             /* 0x30 */
    &_sys_ukn,             /* 0x31 */
    &_sys_ukn,             /* 0x32 */
    &_sys_ukn,             /* 0x33 */
    &_sys_ukn,             /* 0x34 */
    &_sys_ukn,             /* 0x35 */ 
    &_sys_ukn,             /* 0x36 */
    &_sys_ukn,             /* 0x37 */
    &_sys_ukn,             /* 0x38 */   
    &_sys_ukn,             /* 0x39 */
    &_sys_ukn,             /* 0x3A */
    &_sys_ukn,             /* 0x3B */
    &_sys_ukn,             /* 0x3C */
    &_sys_ukn,             /* 0x3D */
    &_sys_ukn,             /* 0x3E */
    &_sys_ukn,             /* 0x3F */
};

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

    _tty_get_lock( 0 );
    _puts("\n\n!!! Undefined System Call !!!\n");
    _puts("\nEPC = ");
    _putx(epc);
    _tty_release_lock( 0 );
    _exit();
}

////////////////////////////////////////////////////////////////////////////
// _exit()
// Task suicide... after printing a death message.
////////////////////////////////////////////////////////////////////////////
void _task_exit() 
{
    unsigned int date    = _get_proctime();
    unsigned int proc_id = _get_procid();
    unsigned int task_id = _get_context_slot(CTX_LTID_ID);

    // print death message
    _tty_get_lock( 0 );
    _puts("\n[GIET] Exit task ");
    _putd(task_id);
    _puts(" on processor ");
    _putd(proc_id);
    _puts(" at cycle ");
    _putd(date);
    _puts("\n\n");
    _tty_release_lock( 0 );

    // goes to sleeping state
    _set_context_slot(CTX_RUN_ID, 0);

    // deschedule
    _context_switch();
} 

//////////////////////////////////////////////////////////////////////////////
// _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_boot_mapping_base;
    mapping_cluster_t * cluster = _get_cluster_base(header);

    if ( cluster_id < X_SIZE * Y_SIZE ) 
    {
        *buffer = cluster[cluster_id].procs;
        return 0;
    }
    else 
    {
        return 1;
    }
}

/////////////////////////////////////////////////////////////////////////////
// _local_task_id()
// Returns current task local index.
/////////////////////////////////////////////////////////////////////////////
unsigned int _local_task_id()
{
    return _get_context_slot(CTX_LTID_ID);
}

/////////////////////////////////////////////////////////////////////////////
// _global_task_id()
// Returns current task global index.
/////////////////////////////////////////////////////////////////////////////
unsigned int _global_task_id()
{
    return _get_context_slot(CTX_GTID_ID);
}

/////////////////////////////////////////////////////////////////////////////
// _thread_id()
// Returns current thread index.
/////////////////////////////////////////////////////////////////////////////
unsigned int _thread_id()
{
    return _get_context_slot(CTX_TRDID_ID);
}

/////////////////////////////////////////////////////////////////////////////
// _tty_get_release_lock(int val)
// Get or release the hardware TTY lock depending on val (0: get,1: release)
/////////////////////////////////////////////////////////////////////////////
int _tty_get_release_lock(unsigned int val)
{
    unsigned int channel = _get_context_slot(CTX_TTY_ID);

    if      ( val == 0 ) _tty_get_lock(channel);
    else if ( val == 1 ) _tty_release_lock(channel);
    else return -1; // Wrong action

    return 0;
}

/////////////////////////////////////////////////////////////////////////////
// _get_vobj()
// This function writes in res_vobj a pointer on a vobj 
// identified by the (vspace_name / vobj_name ) couple.
// The vobj_type argument is here only for the purpose of checking .
// returns 0: success, else: failed.
/////////////////////////////////////////////////////////////////////////////
int _get_vobj( char*             vspace_name, 
               char*             vobj_name, 
               unsigned int      vobj_type, 
               mapping_vobj_t**  res_vobj ) 
{
    mapping_header_t * header = (mapping_header_t *) &seg_boot_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) 
                    {
                        _tty_get_lock( 0 );
                        _puts("*** Error in _get_obj: wrong type\n");
                        _tty_release_lock( 0 );
                        return -1; // wrong type
                    }
                    *res_vobj = &vobj[vobj_id];
                    return 0;
                }
            } 
        }
    } 
    _tty_get_lock( 0 );
    _puts("*** Error in _get_obj: object not found\n");
    _tty_release_lock( 0 );

    return -2; //not found 
}

/////////////////////////////////////////////////////////////////////////////
// _vobj_get_vbase()
// This function writes in vobj_vaddr the virtual base address of a vobj 
// identified by the (vspace_name / vobj_name ) couple.
// The vobj_type argument is here only for the purpose of checking .
// 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_vobj_t* res_vobj;
    unsigned int    ret;
    if ((ret = _get_vobj(vspace_name, vobj_name, vobj_type, &res_vobj))) 
    {
        return ret;
    }
    *vobj_vaddr = res_vobj->vaddr;
    return 0;
}

/////////////////////////////////////////////////////////////////////////////
// _vobj_get_length()
// This function writes in vobj_length the virtual base address of a vobj 
// identified by the (vspace_name / vobj_name ) couple.
// The vobj_type argument is here only for the purpose of checking .
// returns 0: success, else: failed.
/////////////////////////////////////////////////////////////////////////////
unsigned int _vobj_get_length( char*         vspace_name, 
                               char*         vobj_name,
                               unsigned int  vobj_type, 
                               unsigned int* vobj_length ) 
{
    mapping_vobj_t * res_vobj;
    unsigned int ret;
    if ((ret = _get_vobj(vspace_name, vobj_name, vobj_type, &res_vobj))) 
    {
        return ret;
    }
    *vobj_length = res_vobj->length;
    return 0;
}


////////////////////////////////////////////////////////////////
// _context_switch()
// This functions masks interruptions before calling _ctx_switch
// (They are usually masked when we receive a isr_switch interrupt
// because we execute ISRs with interrupt masked)
////////////////////////////////////////////////////////////////
void _context_switch() 
{
    _it_disable();
    _ctx_switch();
}


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