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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>
 *   (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
 */

/*
 * 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 <tracer.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) ) {
/*    if (TIMESPEC_A_LT_B(&lev->cbs_dline[p], acttime) )
      kern_printf("$");
    else
      kern_printf("(Ûdline%d.%d act%d.%d wcet%d per%d avail%dÛ)",
                  lev->cbs_dline[p].tv_sec,lev->cbs_dline[p].tv_nsec/1000,
                  acttime->tv_sec, acttime->tv_nsec/1000,
                  proc_table[p].wcet, lev->period[p], proc_table[p].avail_time);
*/  /* 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_reload(HCBS_level_des *lev, PID p)
{

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

static void HCBS_avail_time_check(HCBS_level_des *lev, PID p)
{
  /* Only one time due to hard reservation */
  if (proc_table[p].avail_time < 0)
    ADDUSEC2TIMESPEC(lev->period[p], &lev->cbs_dline[p]);

}


/* 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;
    proc_table[p].avail_time = proc_table[p].wcet;
    NULL_TIMESPEC(&lev->cbs_dline[p]);
    return;
  }

  /* Hard reservation avail_time reload */
  HCBS_reload(lev, p);

  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]++;

  if (!(lev->flag[p] & HCBS_APERIODIC)) {
    /* repost the event at the next period end... */
    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 */
  TRACER_LOGEVENT(FTrace_EVT_task_timer,(unsigned short int)proc_table[p].context,(unsigned int)proc_table[p].task_level);  

}

/*+ 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;
  HCBS_level_des *lev;

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

  /* we finally put the task in the ready 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) {
   
    /* Set the overload flag */
    lev->flag[p] |= HCBS_OVERLOAD;

    /* we kill the current activation */
    level_table[ lev->scheduling_level ]->
      private_extract(lev->scheduling_level, p);

    /* we modify the deadline according to rule 4 ... */
    HCBS_avail_time_check(lev, 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) {
    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);
  }
//  kern_printf("act : %d %d |",lev->cbs_dline[p].tv_nsec/1000,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_level_des *lev = (HCBS_level_des *)(level_table[l]);
  HCBS_command_message *msg;

  switch((long)(m)) {

    case (long)(NULL):

      /* check if the wcet is finished... */
      HCBS_avail_time_check(lev, p);

      if (lev->flag[p] & HCBS_OVERLOAD) {
        lev->nact[p]++;
        lev->flag[p] &= ~HCBS_OVERLOAD;
      }

      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... */
      TRACER_LOGEVENT(FTrace_EVT_task_end_cycle,(unsigned short int)proc_table[p].context,(unsigned int)l);

      break;

    case 1:

      lev->flag[p] |= HCBS_SLEEP;
      TRACER_LOGEVENT(FTrace_EVT_task_disable,(unsigned short int)proc_table[p].context,(unsigned int)l);

      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;
      }

  }

  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);

  /* and 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) ||
      (lev->flag[p] & HCBS_APERIODIC && lev->flag[p] & HCBS_OVERLOAD)) {
    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];

  /* 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];
}