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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: rm.c,v 1.4 2003-01-07 17:07:50 pj Exp $

 File:        $File$

 Revision:    $Revision: 1.4 $

 Last update: $Date: 2003-01-07 17:07:50 $

 ------------

 This file contains the scheduling module RM (Rate Monotonic)

 Read rm.h for further details.

 This file is equal to EDF.c except for:

 . EDF changed to RM :-)

 . q_timespec_insert changed to q_insert

 . proc_table[p].priority is also modified when we modify lev->period[p]

**/

/*

 * Copyright (C) 2000,2002 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/rm.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 RM_READY         MODULE_STATUS_BASE    /*+ - Ready status        +*/

#define RM_WCET_VIOLATED MODULE_STATUS_BASE+2  /*+ when wcet is finished +*/

#define RM_WAIT          MODULE_STATUS_BASE+3  /*+ to wait the deadline  +*/

#define RM_IDLE          MODULE_STATUS_BASE+4  /*+ to wait the deadline  +*/

#define RM_ZOMBIE        MODULE_STATUS_BASE+5  /*+ to wait the free time +*/

/*+ flags +*/

#define RM_FLAG_SPORADIC    1

#define RM_FLAG_NORAISEEXC  2

/*+ the level redefinition for the Rate Monotonic +*/

typedef struct {

  level_des l;     /*+ the standard level descriptor          +*/

  TIME period[MAX_PROC]; /*+ The task periods; the deadlines are

                       stored in the priority field           +*/

  int deadline_timer[MAX_PROC];

                   /*+ The task deadline timers               +*/

  int flag[MAX_PROC];

                   /*+ used to manage the JOB_TASK_MODEL and the

                       periodicity                            +*/

  IQUEUE ready;     /*+ the ready queue                        +*/

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

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

} RM_level_des;

static void RM_timer_deadline(void *par)

{

  PID p = (PID) par;

  RM_level_des *lev;

  struct timespec *temp;

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

  switch (proc_table[p].status) {

    case RM_ZOMBIE:

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

      proc_table[p].status = FREE;

      iq_insertfirst(p,&freedesc);

      /* and free the allocated bandwidth */

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

      break;

    case RM_IDLE:

      /* tracer stuff */

      trc_logevent(TRC_INTACTIVATION,&p);

      /* similar to RM_task_activate */

      temp = iq_query_timespec(p, &lev->ready);

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

      proc_table[p].status = RM_READY;

      iq_priority_insert(p,&lev->ready);

      lev->deadline_timer[p] = kern_event_post(temp,

                                               RM_timer_deadline,

                                               (void *)p);

      //printk("(d%d idle priority set to %d)",p,proc_table[p].priority );

      event_need_reschedule();

      printk("el%d|",p);

      break;

    case RM_WAIT:

      /* Without this, the task cannot be reactivated!!! */

      proc_table[p].status = SLEEP;

      break;

    default:

      /* else, a deadline miss occurred!!! */

      kern_printf("timer_deadline:AAARRRGGGHHH!!!");

      kern_raise(XDEADLINE_MISS,p);

  }

}

static void RM_timer_guest_deadline(void *par)

{

  PID p = (PID) par;

  kern_printf("AAARRRGGGHHH!!!");

  kern_raise(XDEADLINE_MISS,p);

}

/* The scheduler only gets the first task in the queue */

static PID RM_public_scheduler(LEVEL l)

{

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

  return iq_query_first(&lev->ready);

}

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

static int RM_public_guarantee(LEVEL l, bandwidth_t *freebandwidth)

{

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

  if (lev->flags & RM_FAILED_GUARANTEE) {

    *freebandwidth = 0;

    return 0;

  }

  else

    if (*freebandwidth >= lev->U) {

      *freebandwidth -= lev->U;

      return 1;

    }

    else

      return 0;

}

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

{

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

  HARD_TASK_MODEL *h;

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

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

  h = (HARD_TASK_MODEL *)m;

  if (!h->wcet || !h->mit) return -1;

  /* now we know that m is a valid model */

  *iq_query_priority(p, &lev->ready) = lev->period[p] = h->mit;

  if (h->periodicity == APERIODIC)

    lev->flag[p] = RM_FLAG_SPORADIC;

  else

    lev->flag[p] = 0;

  lev->deadline_timer[p] = -1;

  /* Enable wcet check */

  if (lev->flags & RM_ENABLE_WCET_CHECK) {

    proc_table[p].avail_time = h->wcet;

    proc_table[p].wcet       = h->wcet;

    proc_table[p].control |= CONTROL_CAP;

  }

  /* update the bandwidth... */

  if (lev->flags & RM_ENABLE_GUARANTEE) {

    bandwidth_t b;

    b = (MAX_BANDWIDTH / h->mit) * h->wcet;

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

    if (MAX_BANDWIDTH - lev->U > b)

      lev->U += b;

    else

      /* The task can NOT be guaranteed (U>MAX_BANDWIDTH)...

         in this case, we don't raise an exception... in fact, after the

         RM_task_create the task_create will call level_guarantee that return

         -1... return -1 in RM_task_create isn't correct, because:

           . generally, the guarantee must be done when also the resources

             are registered

           . returning -1 will cause the task_create to return with an errno

             ETASK_CREATE instead of ENO_GUARANTEE!!!

         Why I use the flag??? because if the lev->U overflows, if i.e. I set

         it to MAX_BANDWIDTH, I lose the correct allocated bandwidth...

      */

      lev->flags |= RM_FAILED_GUARANTEE;

  }

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

}

static void RM_public_detach(LEVEL l, PID p)

{

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

     we have only to reset the NO_GUARANTEE FIELD and decrement the allocated

     bandwidth */

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

  if (lev->flags & RM_FAILED_GUARANTEE)

    lev->flags &= ~RM_FAILED_GUARANTEE;

  else

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

}

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

{

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

//  kern_printf("(disp %d)",p);

  /* the task state is set EXE by the scheduler()

     we extract the task from the ready queue

     NB: we can't assume that p is the first task in the queue!!! */

  iq_extract(p, &lev->ready);

}

static void RM_public_epilogue(LEVEL l, PID p)

{

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

//  kern_printf("(epil %d)",p);

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

  if ((lev->flags & RM_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 = RM_WCET_VIOLATED;

  }

  else {

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

    iq_priority_insert(p,&lev->ready);

    proc_table[p].status = RM_READY;

  }

}

static void RM_public_activate(LEVEL l, PID p)

{

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

  struct timespec *temp;

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

    kern_raise(XACTIVATION,p);

    return;

  }

  /* Test if we are trying to activate a non sleeping task    */

  /* Ignore this; the task is already active                  */

  if (proc_table[p].status != SLEEP &&

      proc_table[p].status != RM_WCET_VIOLATED)

    return;

  /* see also RM_timer_deadline */

  temp = iq_query_timespec(p, &lev->ready);

  kern_gettime(temp);

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

  /* Insert task in the correct position */

  proc_table[p].status = RM_READY;

  iq_priority_insert(p,&lev->ready);

  /* Set the deadline timer */

  lev->deadline_timer[p] = kern_event_post(temp,

                                           RM_timer_deadline,

                                           (void *)p);

}

static void RM_public_unblock(LEVEL l, PID p)

{

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

  /* Similar to RM_task_activate,

     but we don't check in what state the task is */

  /* Insert task in the correct position */

  proc_table[p].status = RM_READY;

  iq_priority_insert(p,&lev->ready);

}

static void RM_public_block(LEVEL l, PID p)

{

  /* Extract the running task from the level

     . we have already extract it from the ready queue at the dispatch time.

     . the capacity event have to be removed by the generic kernel

     . the wcet don't need modification...

     . the state of the task is set by the calling function

     . the deadline must remain...

     So, we do nothing!!!

  */

}

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

{

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

  /* the task has terminated his job before it consume the wcet. All OK! */

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

    proc_table[p].status = RM_WAIT;

  else /* pclass = sporadic_pclass */

    proc_table[p].status = RM_IDLE;

  /* we reset the capacity counters... */

  if (lev->flags & RM_ENABLE_WCET_CHECK)

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

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

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

  /* when the deadline timer fire, it recognize the situation and set

     correctly all the stuffs (like reactivation, sleep, etc... ) */

  return 0;

}

static void RM_public_end(LEVEL l, PID p)

{

  proc_table[p].status = RM_ZOMBIE;

  /* When the deadline timer fire, it put the task descriptor in

     the free queue, and free the allocated bandwidth... */

}

static void RM_private_insert(LEVEL l, PID p, TASK_MODEL *m)

{

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

  JOB_TASK_MODEL *job;

  if (m->pclass != JOB_PCLASS || (m->level != 0 && m->level != l) ) {

    kern_raise(XINVALID_TASK, p);

    return;

  }

  job = (JOB_TASK_MODEL *)m;

  *iq_query_timespec(p,&lev->ready) = job->deadline;

  *iq_query_priority(p, &lev->ready) = lev->period[p] = job->period;

  lev->deadline_timer[p] = -1;

  /* Insert task in the correct position */

  iq_priority_insert(p,&lev->ready);

  proc_table[p].status = RM_READY;

  if (job->noraiseexc)

    lev->flag[p] = RM_FLAG_NORAISEEXC;

  else {

    lev->flag[p] = 0;

    lev->deadline_timer[p] = kern_event_post(iq_query_timespec(p, &lev->ready),

                                             RM_timer_guest_deadline,

                                             (void *)p);

  }

}

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

{

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

  /* the task state is set to EXE by the scheduler()

     we extract the task from the ready queue

     NB: we can't assume that p is the first task in the queue!!! */

  iq_extract(p, &lev->ready);

}

static void RM_private_epilogue(LEVEL l, PID p)

{

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

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

  iq_priority_insert(p,&lev->ready);

  proc_table[p].status = RM_READY;

}

static void RM_private_extract(LEVEL l, PID p)

{

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

  //kern_printf("RM_guest_end: dline timer %d\n",lev->deadline_timer[p]);

  if (proc_table[p].status == RM_READY)

  {

    iq_extract(p, &lev->ready);

    //kern_printf("(g_end rdy extr)");

  }

  /* we remove the deadline timer, because the slice is finished */

  if (lev->deadline_timer[p] != NIL) {

//    kern_printf("RM_guest_end: dline timer %d\n",lev->deadline_timer[p]);

    kern_event_delete(lev->deadline_timer[p]);

    lev->deadline_timer[p] = NIL;

  }

}

/* Registration functions */

/*+ Registration function:

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

LEVEL RM_register_level(int flags)

{

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

  RM_level_des *lev;  /* for readableness only */

  PID i;              /* a counter */

  printk("RM_register_level\n");

  /* request an entry in the level_table */

  l = level_alloc_descriptor(sizeof(RM_level_des));

  lev = (RM_level_des *)level_table[l];

  printk("    lev=%d\n",(int)lev);

  /* fill the standard descriptor */

  lev->l.private_insert   = RM_private_insert;

  lev->l.private_extract  = RM_private_extract;

  lev->l.private_dispatch = RM_private_dispatch;

  lev->l.private_epilogue = RM_private_epilogue;

  lev->l.public_scheduler = RM_public_scheduler;

  if (flags & RM_ENABLE_GUARANTEE)

    lev->l.public_guarantee = RM_public_guarantee;

  else

    lev->l.public_guarantee = NULL;

  lev->l.public_create    = RM_public_create;

  lev->l.public_detach    = RM_public_detach;

  lev->l.public_end       = RM_public_end;

  lev->l.public_dispatch  = RM_public_dispatch;

  lev->l.public_epilogue  = RM_public_epilogue;

  lev->l.public_activate  = RM_public_activate;

  lev->l.public_unblock   = RM_public_unblock;

  lev->l.public_block     = RM_public_block;

  lev->l.public_message   = RM_public_message;

  /* fill the RM descriptor part */

  for(i=0; i<MAX_PROC; i++) {

    lev->period[i]         = 0;

    lev->deadline_timer[i] = -1;

    lev->flag[i]          = 0;

  }

  iq_init(&lev->ready, &freedesc, 0);

  lev->flags = flags & 0x07;

  lev->U     = 0;

  return l;

}

bandwidth_t RM_usedbandwidth(LEVEL l)

{

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

  return lev->U;

}