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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: rr.c,v 1.3 2002-11-11 08:32:06 pj Exp $

 File:        $File$

 Revision:    $Revision: 1.3 $

 Last update: $Date: 2002-11-11 08:32:06 $

 ------------

 This file contains the scheduling module RR (Round Robin)

 Read rr.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/rr.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>

/*+ Status used in the level +*/

#define RR_READY   MODULE_STATUS_BASE

/*+ the level redefinition for the Round Robin level +*/

typedef struct {

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

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

  int slice;       /*+ the level's time slice                 +*/

  struct multiboot_info *multiboot; /*+ used if the level have to insert

                                        the main task +*/

} RR_level_des;

static char *RR_status_to_a(WORD status)

{

  if (status < MODULE_STATUS_BASE)

    return status_to_a(status);

  switch (status) {

    case RR_READY: return "RR_Ready";

    default      : return "RR_Unknown";

  }

}

static int RR_level_accept_task_model(LEVEL l, TASK_MODEL *m)

{

  if (m->pclass == NRT_PCLASS || m->pclass == (NRT_PCLASS | l))

    return 0;

  else

    return -1;

}

static int RR_level_accept_guest_model(LEVEL l, TASK_MODEL *m)

{

    return -1;

}

static void RR_level_status(LEVEL l)

{

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

  PID p = iq_query_first(&lev->ready);

  kern_printf("Slice: %d \n", lev->slice);

  while (p != NIL) {

    kern_printf("Pid: %d\t Name: %20s Status: %s\n",p,proc_table[p].name,

              RR_status_to_a(proc_table[p].status));

    p = iq_query_next(p,&lev->ready);

  }

  for (p=0; p<MAX_PROC; p++)

    if (proc_table[p].task_level == l && proc_table[p].status != RR_READY

        && proc_table[p].status != FREE )

      kern_printf("Pid: %d\t Name: %20s Status: %s\n",p,proc_table[p].name,

                RR_status_to_a(proc_table[p].status));

}

/* This is not efficient but very fair :-)

   The need of all this stuff is because if a task execute a long time

   due to (shadow!) priority inheritance, then the task shall go to the

   tail of the queue many times... */

static PID RR_level_scheduler(LEVEL l)

{

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

  PID p;

  for (;;) {

    p = iq_query_first(&lev->ready);

    if (p == -1)

      return p;

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

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

      iq_extract(p,&lev->ready);

      iq_insertlast(p,&lev->ready);

    }

    else

      return p;

  }

}

static int RR_level_guarantee(LEVEL l, bandwidth_t *freebandwidth)

{

  /* the RR level always guarantee... the function is defined because

     there can be an aperiodic server at a level with less priority than

     the RR that need guarantee (e.g., a TBS server) */

  return 1;

}

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

{

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

  NRT_TASK_MODEL *nrt = (NRT_TASK_MODEL *)m;

  /* the task state is set at SLEEP by the general task_create

     the only thing to set remains the capacity stuffs that are set

     to the values passed in the model... */

  /* I used the wcet field because using wcet can account if a task

     consume more than the timeslice... */

  if (nrt->slice) {

    proc_table[p].avail_time = nrt->slice;

    proc_table[p].wcet       = nrt->slice;

  }

  else {

    proc_table[p].avail_time = lev->slice;

    proc_table[p].wcet       = lev->slice;

  }

  proc_table[p].control   |= CONTROL_CAP;

  return 0; /* OK */

}

static void RR_task_detach(LEVEL l, PID p)

{

  /* the RR level doesn't introduce any new field in the TASK_MODEL

     so, all detach stuffs are done by the task_create

     The task state is set at FREE by the general task_create */

}

static int RR_task_eligible(LEVEL l, PID p)

{

  return 0; /* if the task p is chosen, it is always eligible */

}

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

{

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

  /* 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 RR_task_epilogue(LEVEL l, PID p)

{

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

  /* check if the slice is finished and insert the task in the correct

     qqueue position */

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

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

    iq_insertlast(p,&lev->ready);

  }

  else

    /* curr is >0, so the running task have to run for another curr usec */

    iq_insertfirst(p,&lev->ready);

  proc_table[p].status = RR_READY;

}

static void RR_task_activate(LEVEL l, PID p)

{

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

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

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

  if (proc_table[p].status != SLEEP)

    return;

  ll_gettime(TIME_EXACT, &proc_table[p].request_time);

  /* Insert task in the correct position */

  proc_table[p].status = RR_READY;

  iq_insertlast(p,&lev->ready);

}

static void RR_task_insert(LEVEL l, PID p)

{

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

  /* Similar to RR_task_activate, but we don't check in what state

     the task is and we don't set the request_time */

  /* Insert task in the correct position */

  proc_table[p].status = RR_READY;

  iq_insertlast(p,&lev->ready);

}

static void RR_task_extract(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

     So, we do nothing!!!

  */

}

static void RR_task_endcycle(LEVEL l, PID p)

{

//  RR_level_des *lev = (RR_level_des *)(level_table[l]);

  /* this function is equal to the RR_task_extract, except that

     the task fall asleep... */

  proc_table[p].status = SLEEP;

}

static void RR_task_end(LEVEL l, PID p)

{

//  RR_level_des *lev = (RR_level_des *)(level_table[l]);

  /* we insert the task in the free queue */

  proc_table[p].status = FREE;

  iq_insertlast(p,&freedesc);

}

static void RR_task_sleep(LEVEL l, PID p)

{

  proc_table[p].status = SLEEP;

}

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

{ kern_raise(XINVALID_GUEST,exec_shadow); return 0; }

static void RR_guest_detach(LEVEL l, PID p)

{ kern_raise(XINVALID_GUEST,exec_shadow); }

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

{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR_guest_epilogue(LEVEL l, PID p)

{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR_guest_activate(LEVEL l, PID p)

{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR_guest_insert(LEVEL l, PID p)

{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR_guest_extract(LEVEL l, PID p)

{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR_guest_endcycle(LEVEL l, PID p)

{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR_guest_end(LEVEL l, PID p)

{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR_guest_sleep(LEVEL l, PID p)

{ kern_raise(XINVALID_GUEST,exec_shadow); }

/* Registration functions */

/*+ This init function install the "main" task +*/

static void RR_call_main(void *l)

{

  LEVEL lev;

  PID p;

  NRT_TASK_MODEL m;

  void *mb;

  lev = (LEVEL)l;

  nrt_task_default_model(m);

  nrt_task_def_level(m,lev); /* with this we are sure that the task arrives

                                to the correct level */

  mb = ((RR_level_des *)level_table[lev])->multiboot;

  nrt_task_def_arg(m,mb);

  nrt_task_def_usemath(m);

  nrt_task_def_nokill(m);

  nrt_task_def_ctrl_jet(m);

  p = task_create("Main", __init__, (TASK_MODEL *)&m, NULL);

  if (p == NIL)

    kern_printf("\nPanic!!! can't create main task... errno =%d\n",errno);

  RR_task_activate(lev,p);

}

/*+ Registration function:

    TIME slice                the slice for the Round Robin queue

    int createmain            1 if the level creates the main task 0 otherwise

    struct multiboot_info *mb used if createmain specified   +*/

void RR_register_level(TIME slice,

                       int createmain,

                       struct multiboot_info *mb)

{

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

  RR_level_des *lev;  /* for readableness only */

  printk("RR_register_level\n");

  /* request an entry in the level_table */

  l = level_alloc_descriptor();

  /* alloc the space needed for the RR_level_des */

  lev = (RR_level_des *)kern_alloc(sizeof(RR_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,  RR_LEVELNAME, MAX_LEVELNAME);

  lev->l.level_code               = RR_LEVEL_CODE;

  lev->l.level_version            = RR_LEVEL_VERSION;

  lev->l.level_accept_task_model  = RR_level_accept_task_model;

  lev->l.level_accept_guest_model = RR_level_accept_guest_model;

  lev->l.level_status             = RR_level_status;

  lev->l.level_scheduler          = RR_level_scheduler;

  lev->l.level_guarantee          = RR_level_guarantee;

  lev->l.task_create              = RR_task_create;

  lev->l.task_detach              = RR_task_detach;

  lev->l.task_eligible            = RR_task_eligible;

  lev->l.task_dispatch            = RR_task_dispatch;

  lev->l.task_epilogue            = RR_task_epilogue;

  lev->l.task_activate            = RR_task_activate;

  lev->l.task_insert              = RR_task_insert;

  lev->l.task_extract             = RR_task_extract;

  lev->l.task_endcycle            = RR_task_endcycle;

  lev->l.task_end                 = RR_task_end;

  lev->l.task_sleep               = RR_task_sleep;

  lev->l.guest_create             = RR_guest_create;

  lev->l.guest_detach             = RR_guest_detach;

  lev->l.guest_dispatch           = RR_guest_dispatch;

  lev->l.guest_epilogue           = RR_guest_epilogue;

  lev->l.guest_activate           = RR_guest_activate;

  lev->l.guest_insert             = RR_guest_insert;

  lev->l.guest_extract            = RR_guest_extract;

  lev->l.guest_endcycle           = RR_guest_endcycle;

  lev->l.guest_end                = RR_guest_end;

  lev->l.guest_sleep              = RR_guest_sleep;

  /* fill the RR descriptor part */

  iq_init(&lev->ready, &freedesc, 0);

  if (slice < RR_MINIMUM_SLICE) slice = RR_MINIMUM_SLICE;

  if (slice > RR_MAXIMUM_SLICE) slice = RR_MAXIMUM_SLICE;

  lev->slice      = slice;

  lev->multiboot  = mb;

  if (createmain)

    sys_atrunlevel(RR_call_main,(void *) l, RUNLEVEL_INIT);

}