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/*
 * Project: S.Ha.R.K.
 *
 * Coordinators:
 *   Giorgio Buttazzo    <giorgio@sssup.it>
 *   Paolo Gai           <pj@gandalf.sssup.it>
 *
 * Authors     :
 *   Paolo Gai           <pj@gandalf.sssup.it>
 *   Massimiliano Giorgi <massy@gandalf.sssup.it>
 *   Luca Abeni          <luca@gandalf.sssup.it>
 *   (see the web pages for full authors list)
 *
 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
 *
 * http://www.sssup.it
 * http://retis.sssup.it
 * http://shark.sssup.it
 */

/**
 ------------
 CVS :        $Id: tbs.c,v 1.3 2002-11-11 08:32:07 pj Exp $

 File:        $File$
 Revision:    $Revision: 1.3 $
 Last update: $Date: 2002-11-11 08:32:07 $
 ------------

 This file contains the aperiodic server TBS (Total Bandwidth Server)

 Read tbs.h for further details.

**/

/*
 * Copyright (C) 2000 Paolo Gai
 *
 * This program 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */


#include <modules/tbs.h>
#include <ll/stdio.h>
#include <ll/string.h>
#include <kernel/model.h>
#include <kernel/descr.h>
#include <kernel/var.h>
#include <kernel/func.h>

/*+ 4 debug purposes +*/
#undef TBS_TEST

/*+ Status used in the level +*/
#define TBS_WCET_VIOLATED APER_STATUS_BASE+2  /*+ when wcet is finished +*/
#define TBS_WAIT          APER_STATUS_BASE    /*+ waiting the service   +*/

/*+ task flags +*/
#define TBS_SAVE_ARRIVALS 1

/*+ the level redefinition for the Total Bandwidth Server level +*/
typedef struct {
  level_des l;     /*+ the standard level descriptor          +*/

  /* The wcet are stored in the task descriptor's priority
     field.                     */

  int nact[MAX_PROC];    /*+ used to record activations +*/
  BYTE flag[MAX_PROC];

  struct timespec lastdline; /*+ the last deadline assigned to
                                 a TBS task                   +*/

  IQUEUE wait;      /*+ the wait queue of the TBS              +*/
  PID activated;   /*+ the task inserted in another queue     +*/

  int flags;       /*+ the init flags...                      +*/

  bandwidth_t U;   /*+ the used bandwidth by the server       +*/
  int band_num;
  int band_den;

  LEVEL scheduling_level;

} TBS_level_des;


static char *TBS_status_to_a(WORD status)
{
  if (status < MODULE_STATUS_BASE)
    return status_to_a(status);

  switch (status) {
    case TBS_WCET_VIOLATED: return "TBS_Wcet_Violated";
    case TBS_WAIT         : return "TBS_Wait";
    default               : return "TBS_Unknown";
  }
}

#ifdef TESTG
#include "drivers/glib.h"
#endif

/* This static function activates the task pointed by lev->activated) */
static __inline__ void TBS_activation(TBS_level_des *lev)
{
    PID p;             /* for readableness    */
    JOB_TASK_MODEL j;  /* the guest model     */
    TIME drel;         /* the relative deadline of the task */
    LEVEL m;           /* the master level... only for readableness */

#ifdef TESTG
    TIME x;
    extern TIME starttime;
#endif

    p = lev->activated;
    /* we compute a suitable deadline for the task */
    drel = (proc_table[p].wcet * lev->band_den) / lev->band_num;

    if (TIMESPEC_A_GT_B(&proc_table[p].request_time, &lev->lastdline))
      TIMESPEC_ASSIGN(&lev->lastdline, &proc_table[p].request_time );

    ADDUSEC2TIMESPEC(drel, &lev->lastdline);

#ifdef TESTG
    if (starttime) {
    x = ((lev->lastdline.tv_sec*1000000+lev->lastdline.tv_nsec/1000)/5000 - starttime) + 20;
    if (x<640)
      grx_plot(x, 15, 7);
    }
#endif

    /* and we insert the task in another level */
    m = lev->scheduling_level;
    job_task_default_model(j,lev->lastdline);
    level_table[m]->guest_create(m,p,(TASK_MODEL *)&j);
    level_table[m]->guest_activate(m,p);

    #ifdef TBS_TEST
    kern_printf("TBS_activation: lastdline %ds %dns\n",lev->lastdline.tv_sec,lev->lastdline.tv_nsec);
    #endif
}

/* This static function reclaims the unused time of the task p */
static __inline__ void TBS_bandwidth_reclaiming(TBS_level_des *lev, PID p)
{
    TIME reclaimed;
    struct timespec r, sos;

//    kern_printf("%d ", proc_table[p].avail_time);
    reclaimed = (proc_table[p].avail_time * lev->band_den) / lev->band_num;

    r.tv_nsec = (reclaimed % 1000000) * 1000;
    r.tv_sec  = reclaimed / 1000000;

    SUBTIMESPEC(&lev->lastdline, &r, &sos);
    TIMESPEC_ASSIGN(&lev->lastdline, &sos);

    #ifdef TBS_TEST
    kern_printf("TBS_bandwidth_reclaiming: lastdline %ds %dns, reclaimed %d, avail %d\n",
              lev->lastdline.tv_sec, lev->lastdline.tv_nsec, reclaimed, proc_table[p].avail_time);
    #endif
}



static int TBS_level_accept_task_model(LEVEL l, TASK_MODEL *m)
{
  if (m->pclass == SOFT_PCLASS || m->pclass == (SOFT_PCLASS | l) ) {
    SOFT_TASK_MODEL *s = (SOFT_TASK_MODEL *)m;

    if (s->wcet && s->periodicity == APERIODIC)
      return 0;
  }

  return -1;
}

static int TBS_level_accept_guest_model(LEVEL l, TASK_MODEL *m)
{
  return -1;
}

static char *onoff(int i)
{
  if (i)
    return "On ";
  else
    return "Off";
}

static void TBS_level_status(LEVEL l)
{
  TBS_level_des *lev = (TBS_level_des *)(level_table[l]);
  PID p = iq_query_first(&lev->wait);

  kern_printf("Wcet     Check    : %s\n",
            onoff(lev->flags & TBS_ENABLE_WCET_CHECK));
  kern_printf("On-line guarantee : %s\n",
            onoff(lev->flags & TBS_ENABLE_GUARANTEE));
  kern_printf("Used Bandwidth    : %u/%u\n",
            lev->U, MAX_BANDWIDTH);
  kern_printf("Last deadline     : %lds %ldns\n",lev->lastdline.tv_sec,
                                             lev->lastdline.tv_nsec);

  if (lev->activated != -1)
    kern_printf("Activated: Pid: %2d Name: %10s Dl: %ld.%9ld nact: %d Stat: %s\n",
              lev->activated,
              proc_table[lev->activated].name,
              iq_query_timespec(lev->activated, &lev->wait)->tv_sec,
              iq_query_timespec(lev->activated, &lev->wait)->tv_nsec,
              lev->nact[lev->activated],
              TBS_status_to_a(proc_table[lev->activated].status));

  while (p != NIL) {
    kern_printf("Pid: %2d Name: %10s Stat: %s\n",
              p,
              proc_table[p].name,
              TBS_status_to_a(proc_table[p].status));
    p = iq_query_next(p, &lev->wait);
  }
}

static PID TBS_level_scheduler(LEVEL l)
{
  /* the TBS don't schedule anything...
     it's an EDF level or similar that do it! */
  return NIL;
}

/* The on-line guarantee is enabled only if the appropriate flag is set... */
static int TBS_level_guarantee(LEVEL l, bandwidth_t *freebandwidth)
{
  TBS_level_des *lev = (TBS_level_des *)(level_table[l]);

  if (*freebandwidth >= lev->U) {
    *freebandwidth -= lev->U;
    return 1;
  }
  else
    return 0;
}

static int TBS_task_create(LEVEL l, PID p, TASK_MODEL *m)
{
  TBS_level_des *lev = (TBS_level_des *)(level_table[l]);

  /* if the TBS_task_create is called, then the pclass must be a
     valid pclass. */
  SOFT_TASK_MODEL *s = (SOFT_TASK_MODEL *)m;

  proc_table[p].wcet       = s->wcet;

  /* Enable wcet check */
  if (lev->flags & TBS_ENABLE_WCET_CHECK) {
    proc_table[p].avail_time = s->wcet;
    proc_table[p].control   |= CONTROL_CAP;
  }

  lev->nact[p] = 0;
  if (s->arrivals == SAVE_ARRIVALS)
    lev->flag[p] = TBS_SAVE_ARRIVALS;

  return 0; /* OK, also if the task cannot be guaranteed... */
}

static void TBS_task_detach(LEVEL l, PID p)
{
  /* the TBS level doesn't introduce any dinamic allocated new field. */
}

static int TBS_task_eligible(LEVEL l, PID p)
{
  return 0; /* if the task p is chosen, it is always eligible */
}

static void TBS_task_dispatch(LEVEL l, PID p, int nostop)
{
  TBS_level_des *lev = (TBS_level_des *)(level_table[l]);

  /* there is at least one task ready inserted in an EDF or similar
     level */

  level_table[ lev->scheduling_level ]->
    guest_dispatch(lev->scheduling_level,p,nostop);
}

static void TBS_task_epilogue(LEVEL l, PID p)
{
  TBS_level_des *lev = (TBS_level_des *)(level_table[l]);

  /* check if the wcet is finished... */
  if ((lev->flags & TBS_ENABLE_WCET_CHECK) && proc_table[p].avail_time <= 0) {
    /* if it is, raise a XWCET_VIOLATION exception */
    kern_raise(XWCET_VIOLATION,p);
    proc_table[p].status = TBS_WCET_VIOLATED;

    /* the current task have to die in the scheduling queue, and another
       have to be put in place... this code is identical to the
       TBS_task_end */
    level_table[ lev->scheduling_level ]->
      guest_end(lev->scheduling_level,p);

    /* we reclaim an avail time that can be <0 due to the timer
       approximations -> we have to postpone the deadline a little!
       we can use the ADDUSEC2TIMESPEC because the time postponed is
       less than 55ms */
    ADDUSEC2TIMESPEC((-proc_table[p].avail_time * lev->band_den)
                     / lev->band_num, &lev->lastdline);

    #ifdef TBS_TEST
    kern_printf("TBS_task_epilogue: Deadline posponed to %ds %dns\n",
              lev->lastdline.tv_sec, lev->lastdline.tv_nsec);
    #endif

    lev->activated = iq_getfirst(&lev->wait);
    if (lev->activated != NIL)
      TBS_activation(lev);
  }
  else
    /* the task has been preempted. it returns into the ready queue by
       calling the guest_epilogue... */
    level_table[ lev->scheduling_level ]->
      guest_epilogue(lev->scheduling_level,p);
}

static void TBS_task_activate(LEVEL l, PID p)
{
  TBS_level_des *lev = (TBS_level_des *)(level_table[l]);

  if (proc_table[p].status == SLEEP ||
       proc_table[p].status == TBS_WCET_VIOLATED) {

    ll_gettime(TIME_EXACT, &proc_table[p].request_time);
 
    if (lev->activated == NIL) {
      /* This is the first task in the level, so we activate it immediately */
      lev->activated = p;
      TBS_activation(lev);
    }
    else {
      proc_table[p].status = TBS_WAIT;
      iq_insertlast(p, &lev->wait);
    }
  }
  else if (lev->flag[p] & TBS_SAVE_ARRIVALS)
    lev->nact[p]++;
/*  else
    kern_printf("TBSREJ!!!");*/
}

static void TBS_task_insert(LEVEL l, PID p)
{
  TBS_level_des *lev = (TBS_level_des *)(level_table[l]);

  level_table[ lev->scheduling_level ]->
    guest_insert(lev->scheduling_level,p);
}

static void TBS_task_extract(LEVEL l, PID p)
{
  TBS_level_des *lev = (TBS_level_des *)(level_table[l]);

  level_table[ lev->scheduling_level ]->
    guest_extract(lev->scheduling_level,p);
}

static void TBS_task_endcycle(LEVEL l, PID p)
{
  TBS_level_des *lev = (TBS_level_des *)(level_table[l]);

  /* a task activation is finished, but we are using a JOB_TASK_MODEL
     that implements a single activation, so we have to call
     the guest_end, that representsa single activation... */
  level_table[ lev->scheduling_level ]->
    guest_end(lev->scheduling_level,p);

  TBS_bandwidth_reclaiming(lev,p);

  /* we reset the capacity counters... */
  if (lev->flags & TBS_ENABLE_WCET_CHECK)
    proc_table[p].avail_time = proc_table[p].wcet;

  if (lev->nact[p]) {
    // lev->nact[p] can be >0 only if the SAVE_ARRIVALS bit is set
    lev->nact[p]--;
    proc_table[p].status = TBS_WAIT;
    iq_insertlast(p, &lev->wait);
  }
  else
    proc_table[p].status = SLEEP;

  lev->activated = iq_getfirst(&lev->wait);
  if (lev->activated != NIL)
    TBS_activation(lev);

}

static void TBS_task_end(LEVEL l, PID p)
{
  TBS_level_des *lev = (TBS_level_des *)(level_table[l]);

  level_table[ lev->scheduling_level ]->
    guest_end(lev->scheduling_level,p);

  TBS_bandwidth_reclaiming(lev,p);

  proc_table[p].status = FREE;
  iq_insertfirst(p,&freedesc);

  lev->activated = iq_getfirst(&lev->wait);
  if (lev->activated != NIL)
    TBS_activation(lev);
}

static void TBS_task_sleep(LEVEL l, PID p)
{
  TBS_level_des *lev = (TBS_level_des *)(level_table[l]);

  /* a task activation is finished, but we are using a JOB_TASK_MODEL
     that implements a single activation, so we have to call
     the guest_end, that representsa single activation... */
  level_table[ lev->scheduling_level ]->
    guest_end(lev->scheduling_level,p);

  TBS_bandwidth_reclaiming(lev,p);

  /* we reset the capacity counters... */
  if (lev->flags & TBS_ENABLE_WCET_CHECK)
    proc_table[p].avail_time = proc_table[p].wcet;

  proc_table[p].status = SLEEP;

  lev->nact[p] = 0;

  lev->activated = iq_getfirst(&lev->wait);
  if (lev->activated != NIL)
    TBS_activation(lev);

}

static int TBS_guest_create(LEVEL l, PID p, TASK_MODEL *m)
{ kern_raise(XINVALID_GUEST,exec_shadow); return 0; }

static void TBS_guest_detach(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void TBS_guest_dispatch(LEVEL l, PID p, int nostop)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void TBS_guest_epilogue(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void TBS_guest_activate(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void TBS_guest_insert(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void TBS_guest_extract(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void TBS_guest_endcycle(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void TBS_guest_end(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void TBS_guest_sleep(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }




/* Registration functions */

/*+ Registration function:
    int flags                 the init flags ... see TBS.h +*/
void TBS_register_level(int flags, LEVEL master, int num, int den)
{
  LEVEL l;            /* the level that we register */
  TBS_level_des *lev;  /* for readableness only */
  PID i;              /* a counter */

  printk("TBS_register_level\n");

  /* request an entry in the level_table */
  l = level_alloc_descriptor();

  printk("    alloco descrittore %d %d\n",l,(int)sizeof(TBS_level_des));

  /* alloc the space needed for the TBS_level_des */
  lev = (TBS_level_des *)kern_alloc(sizeof(TBS_level_des));

  printk("    lev=%d\n",(int)lev);

  /* update the level_table with the new entry */
  level_table[l] = (level_des *)lev;

  /* fill the standard descriptor */
  strncpy(lev->l.level_name,  TBS_LEVELNAME, MAX_LEVELNAME);
  lev->l.level_code               = TBS_LEVEL_CODE;
  lev->l.level_version            = TBS_LEVEL_VERSION;

  lev->l.level_accept_task_model  = TBS_level_accept_task_model;
  lev->l.level_accept_guest_model = TBS_level_accept_guest_model;
  lev->l.level_status             = TBS_level_status;
  lev->l.level_scheduler          = TBS_level_scheduler;

  if (flags & TBS_ENABLE_GUARANTEE)
    lev->l.level_guarantee        = TBS_level_guarantee;
  else
    lev->l.level_guarantee        = NULL;

  lev->l.task_create              = TBS_task_create;
  lev->l.task_detach              = TBS_task_detach;
  lev->l.task_eligible            = TBS_task_eligible;
  lev->l.task_dispatch            = TBS_task_dispatch;
  lev->l.task_epilogue            = TBS_task_epilogue;
  lev->l.task_activate            = TBS_task_activate;
  lev->l.task_insert              = TBS_task_insert;
  lev->l.task_extract             = TBS_task_extract;
  lev->l.task_endcycle            = TBS_task_endcycle;
  lev->l.task_end                 = TBS_task_end;
  lev->l.task_sleep               = TBS_task_sleep;

  lev->l.guest_create             = TBS_guest_create;
  lev->l.guest_detach             = TBS_guest_detach;
  lev->l.guest_dispatch           = TBS_guest_dispatch;
  lev->l.guest_epilogue           = TBS_guest_epilogue;
  lev->l.guest_activate           = TBS_guest_activate;
  lev->l.guest_insert             = TBS_guest_insert;
  lev->l.guest_extract            = TBS_guest_extract;
  lev->l.guest_endcycle           = TBS_guest_endcycle;
  lev->l.guest_end                = TBS_guest_end;
  lev->l.guest_sleep              = TBS_guest_sleep;

  /* fill the TBS descriptor part */

  for (i = 0; i < MAX_PROC; i++) {
    lev->nact[i] = 0;
    lev->flag[i] = 0;
  }

  NULL_TIMESPEC(&lev->lastdline);

  iq_init(&lev->wait, &freedesc, 0);
  lev->activated = NIL;

  lev->U = (MAX_BANDWIDTH / den) * num;
  lev->band_num = num;
  lev->band_den = den;

  lev->scheduling_level = master;

  lev->flags = flags & 0x07;
}

bandwidth_t TBS_usedbandwidth(LEVEL l)
{
  TBS_level_des *lev = (TBS_level_des *)(level_table[l]);
  if (lev->l.level_code    == TBS_LEVEL_CODE &&
      lev->l.level_version == TBS_LEVEL_VERSION)
    return lev->U;
  else
    return 0;
}

int TBS_get_nact(LEVEL l, PID p)
{
  TBS_level_des *lev = (TBS_level_des *)(level_table[l]);
  if (lev->l.level_code    == TBS_LEVEL_CODE &&
      lev->l.level_version == TBS_LEVEL_VERSION)
    return lev->nact[p];
  else
    return -1;
}