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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>

 *   Giacomo Guidi       <giacomo@gandalf.sssup.it>

 *     [Hard Reservation]

 *

 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)

 *

 * http://www.sssup.it

 * http://retis.sssup.it

 * http://shark.sssup.it

 */

/*

 * 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/hardcbs.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>

#include <kernel/trace.h>

/*+ Status used in the level +*/

#define HCBS_IDLE          APER_STATUS_BASE   /*+ waiting the activation +*/

#define HCBS_ZOMBIE        APER_STATUS_BASE+1 /*+ waiting the period end +*/

/*+ task flags +*/

#define HCBS_SAVE_ARRIVALS 1

#define HCBS_APERIODIC     2

#define HCBS_SLEEP         4

#define HCBS_OVERLOAD      8

/*+ 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, but we need

     an array for the deadlines. We can't use the timespec_priority

     field because it is used by the master level!!!...

     Notice that however the use of the timespec_priority field

     does not cause any problem...                     */

  struct timespec cbs_dline[MAX_PROC]; /*+ CBS deadlines      +*/

  TIME period[MAX_PROC]; /*+ CBS activation period            +*/

  struct timespec reactivation_time[MAX_PROC];

        /*+ the time at witch  the reactivation timer is post +*/

  int reactivation_timer[MAX_PROC];

                                   /*+ the recativation timer +*/

  int nact[MAX_PROC]; /*+ number of pending activations       +*/

  BYTE flag[MAX_PROC]; /*+ task flags                         +*/

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

  bandwidth_t U;   /*+ the used bandwidth by the server       +*/

  LEVEL scheduling_level;

} HCBS_level_des;

static void HCBS_activation(HCBS_level_des *lev,

                           PID p,

                           struct timespec *acttime)

{

  JOB_TASK_MODEL job;

  /* we have to check if the deadline and the wcet are correct before

     activating a new task or an old task... */

  /* check 1: if the deadline is before than the actual scheduling time */

  /* check 2: if ( avail_time >= (cbs_dline - acttime)* (wcet/period) )

     (rule 7 in the CBS article!) */

  TIME t;

  struct timespec t2,t3;

  t = (lev->period[p] * proc_table[p].avail_time) / proc_table[p].wcet;

  t3.tv_sec = t / 1000000;

  t3.tv_nsec = (t % 1000000) * 1000;

  SUBTIMESPEC(&lev->cbs_dline[p], acttime, &t2);

  if (/* 1 */ TIMESPEC_A_LT_B(&lev->cbs_dline[p], acttime) ||

      /* 2 */ TIMESPEC_A_GT_B(&t3, &t2) ) {

    /* we modify the deadline ... */

    TIMESPEC_ASSIGN(&lev->cbs_dline[p], acttime);

    ADDUSEC2TIMESPEC(lev->period[p], &lev->cbs_dline[p]);

    /* and the capacity */

    proc_table[p].avail_time = proc_table[p].wcet;

  }

  /* and, finally, we reinsert the task in the master level */

  job_task_default_model(job, lev->cbs_dline[p]);

  job_task_def_noexc(job);

  level_table[ lev->scheduling_level ]->

    private_insert(lev->scheduling_level, p, (TASK_MODEL *)&job);

}

static void HCBS_avail_time_check(HCBS_level_des *lev, PID p)

{

  if (proc_table[p].avail_time < 0) {

    ADDUSEC2TIMESPEC(lev->period[p], &lev->cbs_dline[p]);

    proc_table[p].avail_time += proc_table[p].wcet;

  }

}

/* this is the periodic reactivation of the task... it is posted only

   if the task is a periodic task */

static void HCBS_timer_reactivate(void *par)

{

  PID p = (PID) par;

  HCBS_level_des *lev;

  lev = (HCBS_level_des *)level_table[proc_table[p].task_level];

  if (lev->flag[p] & HCBS_SLEEP && proc_table[p].status == HCBS_IDLE) {

    proc_table[p].status = SLEEP;

    return;

  }

  if (proc_table[p].status == HCBS_IDLE) {

    /* the task has finished the current activation and must be

       reactivated */

    HCBS_activation(lev,p,&lev->reactivation_time[p]);

    event_need_reschedule();

  }

  else if (lev->flag[p] & HCBS_SAVE_ARRIVALS)

    /* the task has not completed the current activation, so we save

       the activation incrementing nact... */

    lev->nact[p]++;

  /* repost the event at the next period end...

     For bandwidth hard reservation, an aperiodic

     task is forced to generate a reactivate event */

  if (!(lev->flag[p] & HCBS_APERIODIC)) {

    ADDUSEC2TIMESPEC(lev->period[p], &lev->reactivation_time[p]);

    lev->reactivation_timer[p] = kern_event_post(&lev->reactivation_time[p],

                                               HCBS_timer_reactivate,

                                               (void *)p);

  }

  /* tracer stuff */

  trc_logevent(TRC_INTACTIVATION,&p);

}

/*+ this function is called when a killed or ended task reach the

    period end +*/

static void HCBS_timer_zombie(void *par)

{

  PID p = (PID) par;

  /* we finally put the task in the free queue */

  proc_table[p].status = FREE;

  iq_insertfirst(p,&freedesc);

}

/* The on-line guarantee is enabled only if the appropriate flag is set... */

static int HCBS_public_guarantee(LEVEL l, bandwidth_t *freebandwidth)

{

  HCBS_level_des *lev = (HCBS_level_des *)(level_table[l]);

  if (*freebandwidth >= lev->U) {

    *freebandwidth -= lev->U;

    return 1;

  }

  else

    return 0;

}

static int HCBS_public_create(LEVEL l, PID p, TASK_MODEL *m)

{

  HCBS_level_des *lev = (HCBS_level_des *)(level_table[l]);

  SOFT_TASK_MODEL *soft;

  if (m->pclass != SOFT_PCLASS) return -1;

  if (m->level != 0 && m->level != l) return -1;

  soft = (SOFT_TASK_MODEL *)m;

  if (!(soft->met && soft->period)) return -1;

  soft = (SOFT_TASK_MODEL *)m;

  if (lev->flags & HCBS_ENABLE_GUARANTEE) {

    bandwidth_t b;

    b = (MAX_BANDWIDTH / soft->period) * soft->met;

    /* really update lev->U, checking an overflow... */

    if (MAX_BANDWIDTH - lev->U > b)

      lev->U += b;

    else

      return -1;

  }

  /* Enable wcet check */

  proc_table[p].avail_time = soft->met;

  proc_table[p].wcet       = soft->met;

  proc_table[p].control   |= CONTROL_CAP;

  lev->nact[p] = 0;

  lev->period[p] = soft->period;

  NULL_TIMESPEC(&lev->cbs_dline[p]);

  if (soft->periodicity == APERIODIC)

    lev->flag[p] = HCBS_APERIODIC;

  else

    lev->flag[p] = 0;

  if (soft->arrivals == SAVE_ARRIVALS)

    lev->flag[p] |= HCBS_SAVE_ARRIVALS;

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

}

static void HCBS_public_detach(LEVEL l, PID p)

{

  /* the CBS level doesn't introduce any dinamic allocated new field.

     we have only to decrement the allocated bandwidth */

  HCBS_level_des *lev = (HCBS_level_des *)(level_table[l]);

  if (lev->flags & HCBS_ENABLE_GUARANTEE) {

    lev->U -= (MAX_BANDWIDTH / lev->period[p]) * proc_table[p].wcet;

  }

}

static int HCBS_public_eligible(LEVEL l, PID p)

{

  HCBS_level_des *lev = (HCBS_level_des *)(level_table[l]);

  JOB_TASK_MODEL job;

  /* we have to check if the deadline and the wcet are correct...

     if the CBS level schedules in background with respect to others

     levels, there can be the case in witch a task is scheduled by

     schedule_time > CBS_deadline; in this case (not covered in the

     article because if there is only the standard scheduling policy

     this never apply) we reassign the deadline */

  if ( TIMESPEC_A_LT_B(&lev->cbs_dline[p], &schedule_time) ) {

    /* we kill the current activation */

    level_table[ lev->scheduling_level ]->

      private_extract(lev->scheduling_level, p);

    /* we modify the deadline ... */

    TIMESPEC_ASSIGN(&lev->cbs_dline[p], &schedule_time);

    ADDUSEC2TIMESPEC(lev->period[p], &lev->cbs_dline[p]);

    /* and the capacity */

    proc_table[p].avail_time = proc_table[p].wcet;

    /* and, finally, we reinsert the task in the master level */

    job_task_default_model(job, lev->cbs_dline[p]);

    job_task_def_noexc(job);

    level_table[ lev->scheduling_level ]->

      private_insert(lev->scheduling_level, p, (TASK_MODEL *)&job);

    return -1;

  }

  return 0;

}

static void HCBS_public_dispatch(LEVEL l, PID p, int nostop)

{

  HCBS_level_des *lev = (HCBS_level_des *)(level_table[l]);

  level_table[ lev->scheduling_level ]->

    private_dispatch(lev->scheduling_level,p,nostop);

}

static void HCBS_public_epilogue(LEVEL l, PID p)

{

  HCBS_level_des *lev = (HCBS_level_des *)(level_table[l]);

  /* check if the wcet is finished... */

  if ( proc_table[p].avail_time <= 0) {

    lev->flag[p] |= HCBS_OVERLOAD;

    /* we kill the current activation */

    level_table[ lev->scheduling_level ]->

      private_extract(lev->scheduling_level, p);

    /* Hard Reservation: The avail_time will be reloaded in the

       next reactivation event. The task is suspended */

    proc_table[p].status = HCBS_IDLE;

    if (lev->flag[p] & HCBS_APERIODIC) {

      ADDUSEC2TIMESPEC(lev->period[p], &lev->reactivation_time[p]);

      lev->reactivation_timer[p] = kern_event_post(&lev->reactivation_time[p],

                                                 HCBS_timer_reactivate,

                                                 (void *)p);

    }

  }

  else

    /* the task has been preempted. it returns into the ready queue by

       calling the guest_epilogue... */

    level_table[ lev->scheduling_level ]->

      private_epilogue(lev->scheduling_level,p);

}

static void HCBS_public_activate(LEVEL l, PID p)

{

  HCBS_level_des *lev = (HCBS_level_des *)(level_table[l]);

  struct timespec t;

  if (lev->flag[p] & HCBS_SLEEP) {

    /* disable HCBS_SLEEP flag */

    lev->flag[p] &= ~HCBS_SLEEP;

    if (proc_table[p].status != SLEEP) return;

  }

  /* save activation (only if needed... */

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

    if (lev->flag[p] & HCBS_SAVE_ARRIVALS)

      lev->nact[p]++;

    return;

  }

  kern_gettime(&t);

  HCBS_activation(lev, p, &t);

  /* Set the reactivation timer */

  if (!(lev->flag[p] & HCBS_APERIODIC))

  {

    /* we cannot use the deadline computed by CBS_activation because

       the deadline may be != from actual_time + period

       (if we call the task_activate after a task_sleep, and the

       deadline was postponed a lot...) */

    TIMESPEC_ASSIGN(&lev->reactivation_time[p], &t);

    ADDUSEC2TIMESPEC(lev->period[p], &lev->reactivation_time[p]);

//    TIMESPEC_ASSIGN(&lev->reactivation_time[p], &lev->cbs_dline[p]);

    lev->reactivation_timer[p] = kern_event_post(&lev->reactivation_time[p],

                                                 HCBS_timer_reactivate,

                                                 (void *)p);

  }

}

static void HCBS_public_unblock(LEVEL l, PID p)

{

  HCBS_level_des *lev = (HCBS_level_des *)(level_table[l]);

  struct timespec acttime;

  kern_gettime(&acttime);

  HCBS_activation(lev,p,&acttime);

}

static void HCBS_public_block(LEVEL l, PID p)

{

  HCBS_level_des *lev = (HCBS_level_des *)(level_table[l]);

  /* check if the wcet is finished... */

  HCBS_avail_time_check(lev, p);

  level_table[ lev->scheduling_level ]->

    private_extract(lev->scheduling_level,p);

}

static int HCBS_public_message(LEVEL l, PID p, void *m)

{

  HCBS_command_message *msg;

  HCBS_level_des *lev = (HCBS_level_des *)(level_table[l]);

  switch((long)(m)) {

    /* task_endcycle */

    case (long)(NULL):

      if  (!(lev->flag[p] & HCBS_APERIODIC) && lev->flag[p] & HCBS_OVERLOAD) {

        lev->flag[p] &= ~HCBS_OVERLOAD;

        lev->nact[p]++;

      }

      if (lev->nact[p]) {

        /* continue!!!! */

        lev->nact[p]--;

        level_table[ lev->scheduling_level ]->

          private_epilogue(lev->scheduling_level,p);

      } else {

        level_table[ lev->scheduling_level ]->

          private_extract(lev->scheduling_level,p);

        if (lev->flag[p] & HCBS_APERIODIC)

          proc_table[p].status = SLEEP;

        else  /* the task is soft_periodic */

          proc_table[p].status = HCBS_IDLE;

      }

      jet_update_endcycle(); /* Update the Jet data... */

      trc_logevent(TRC_ENDCYCLE,&exec_shadow); /* tracer stuff */

      break;

    /* task_disable */

    case (1):

      lev->flag[p] |= HCBS_SLEEP;

      break;

    /* Set/Get Met/Period */

    default:

      msg = (HCBS_command_message *)(m);

      switch (msg->command) {

        case HCBS_SET_PERIOD:

          lev->U -= (bandwidth_t)(MAX_BANDWIDTH / lev->period[p]

                * proc_table[p].wcet);

          lev->period[p] = msg->param;

          lev->U += (bandwidth_t)(MAX_BANDWIDTH / lev->period[p]

                * proc_table[p].wcet);

          break;

        case HCBS_GET_PERIOD:

          msg->param = lev->period[p];

          break;

        case HCBS_SET_MET:

          lev->U -= (bandwidth_t)(MAX_BANDWIDTH / lev->period[p]

                * proc_table[p].wcet);

          proc_table[p].wcet = msg->param;

          lev->U += (bandwidth_t)(MAX_BANDWIDTH / lev->period[p]

                * proc_table[p].wcet);

          break;

        case HCBS_GET_MET:

          msg->param = proc_table[p].wcet;

          break;

      }

      break;

  }

  return 0;

}

static void HCBS_public_end(LEVEL l, PID p)

{

  HCBS_level_des *lev = (HCBS_level_des *)(level_table[l]);

  /* check if the wcet is finished... */

  HCBS_avail_time_check(lev, p);

  level_table[ lev->scheduling_level ]->

    private_extract(lev->scheduling_level,p);

  /* free the allocated bandwidth */

  lev->U -= (MAX_BANDWIDTH/lev->period[p]) * proc_table[p].wcet;

  /* we delete the reactivation timer */

  if (!(lev->flag[p] & HCBS_APERIODIC)) {

    kern_event_delete(lev->reactivation_timer[p]);

    lev->reactivation_timer[p] = -1;

  }

  /* Finally, we post the zombie event. when the end period is reached,

     the task descriptor and banwidth are freed */

  proc_table[p].status = HCBS_ZOMBIE;

  lev->reactivation_timer[p] = kern_event_post(&lev->cbs_dline[p],

                                               HCBS_timer_zombie,

                                               (void *)p);

}

/* Registration functions */

/*+ Registration function:

    int flags                 the init flags ... see CBS.h +*/

LEVEL HCBS_register_level(int flags, LEVEL master)

{

  LEVEL l;            /* the level that we register */

  HCBS_level_des *lev;  /* for readableness only */

  PID i;              /* a counter */

  printk("HCBS_register_level\n");

  /* request an entry in the level_table */

  l = level_alloc_descriptor(sizeof(HCBS_level_des));

  lev = (HCBS_level_des *)level_table[l];

  printk("    lev=%d\n",(int)lev);

  /* fill the standard descriptor */

  if (flags & HCBS_ENABLE_GUARANTEE)

    lev->l.public_guarantee = HCBS_public_guarantee;

  else

    lev->l.public_guarantee = NULL;

  lev->l.public_create    = HCBS_public_create;

  lev->l.public_detach    = HCBS_public_detach;

  lev->l.public_end       = HCBS_public_end;

  lev->l.public_eligible  = HCBS_public_eligible;

  lev->l.public_dispatch  = HCBS_public_dispatch;

  lev->l.public_epilogue  = HCBS_public_epilogue;

  lev->l.public_activate  = HCBS_public_activate;

  lev->l.public_unblock   = HCBS_public_unblock;

  lev->l.public_block     = HCBS_public_block;

  lev->l.public_message   = HCBS_public_message;

  /* fill the CBS descriptor part */

  for (i=0; i<MAX_PROC; i++) {

     NULL_TIMESPEC(&lev->cbs_dline[i]);

     lev->period[i] = 0;

     NULL_TIMESPEC(&lev->reactivation_time[i]);

     lev->reactivation_timer[i] = -1;

     lev->nact[i] = 0;

     lev->flag[i] = 0;

  }

  lev->U = 0;

  lev->scheduling_level = master;

  lev->flags = flags;

  return l;

}

bandwidth_t HCBS_usedbandwidth(LEVEL l)

{

  HCBS_level_des *lev = (HCBS_level_des *)(level_table[l]);

  return lev->U;

}

int HCBS_get_nact(LEVEL l, PID p)

{

  HCBS_level_des *lev = (HCBS_level_des *)(level_table[l]);

  return lev->nact[p];

}