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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: rr2.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 RR2 (Round Robin) version 2

 Read rr2.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 WARR2ANTY; without even the implied waRR2anty 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/rr2.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 RR2_READY   MODULE_STATUS_BASE

/*+ the level redefinition for the Round Robin level +*/
typedef struct {
  level_des l;     /*+ the standard level descriptor          +*/

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

  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 +*/
} RR2_level_des;


static char *RR2_status_to_a(WORD status)
{
  if (status < MODULE_STATUS_BASE)
    return status_to_a(status);

  switch (status) {
    case RR2_READY: return "RR2_Ready";
    default      : return "RR2_Unknown";
  }
}

static int RR2_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 RR2_level_accept_guest_model(LEVEL l, TASK_MODEL *m)
{
    return -1;
}

static void RR2_level_status(LEVEL l)
{
  RR2_level_des *lev = (RR2_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,
              RR2_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 != RR2_READY
        && proc_table[p].status != FREE )
      kern_printf("Pid: %d\t Name: %20s Status: %s\n",p,proc_table[p].name,
                RR2_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 RR2_level_scheduler(LEVEL l)
{
  RR2_level_des *lev = (RR2_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 RR2_level_guarantee(LEVEL l, bandwidth_t *freebandwidth)
{
  /* the RR2 level always guarantee... the function is defined because
     there can be an aperiodic server at a level with less priority than
     the RR2 that need guarantee (e.g., a TBS server) */
  return 1;
}


static int RR2_task_create(LEVEL l, PID p, TASK_MODEL *m)
{
  RR2_level_des *lev = (RR2_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;

  if (nrt->arrivals == SAVE_ARRIVALS)
    lev->nact[p] = 0;
  else
    lev->nact[p] = -1;

  return 0; /* OK */
}

static void RR2_task_detach(LEVEL l, PID p)
{
  /* the RR2 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 RR2_task_eligible(LEVEL l, PID p)
{
  return 0; /* if the task p is chosen, it is always eligible */
}

static void RR2_task_dispatch(LEVEL l, PID p, int nostop)
{
  RR2_level_des *lev = (RR2_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 RR2_task_epilogue(LEVEL l, PID p)
{
  RR2_level_des *lev = (RR2_level_des *)(level_table[l]);

  /* check if the slice is finished and insert the task in the coRR2ect
     qqueue position */
  if (proc_table[p].avail_time <= 0) {
    proc_table[p].avail_time += proc_table[p].wcet;
    iq_insertlast(p,&lev->ready);
  }
  else
    /* cuRR2 is >0, so the running task have to run for another cuRR2 usec */
    iq_insertfirst(p,&lev->ready);

  proc_table[p].status = RR2_READY;
}

static void RR2_task_activate(LEVEL l, PID p)
{
  RR2_level_des *lev = (RR2_level_des *)(level_table[l]);

  /* Test if we are trying to activate a non sleeping task    */
  /* save activation (only if needed... */
  if (proc_table[p].status != SLEEP) {
    if (lev->nact[p] != -1)
      lev->nact[p]++;
    return;
  }

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

  /* Insert task in the coRR2ect position */
  proc_table[p].status = RR2_READY;
  iq_insertlast(p,&lev->ready);
}

static void RR2_task_insert(LEVEL l, PID p)
{
  RR2_level_des *lev = (RR2_level_des *)(level_table[l]);

  /* Similar to RR2_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 coRR2ect position */
  proc_table[p].status = RR2_READY;
  iq_insertlast(p,&lev->ready);
}

static void RR2_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 RR2_task_endcycle(LEVEL l, PID p)
{
  RR2_level_des *lev = (RR2_level_des *)(level_table[l]);

  if (lev->nact[p] > 0) {
    /* continue!!!! */
    ll_gettime(TIME_EXACT, &proc_table[p].request_time);
    lev->nact[p]--;
    iq_insertfirst(p,&lev->ready);
    proc_table[p].status = RR2_READY;
  }
  else
    proc_table[p].status = SLEEP;
}

static void RR2_task_end(LEVEL l, PID p)
{
  RR2_level_des *lev = (RR2_level_des *)(level_table[l]);

  lev->nact[p] = -1;

  /* then, we insert the task in the free queue */
  proc_table[p].status = FREE;
  iq_insertlast(p,&freedesc);
}

static void RR2_task_sleep(LEVEL l, PID p)
{
  RR2_level_des *lev = (RR2_level_des *)(level_table[l]);
  if (lev->nact[p] >= 0) lev->nact[p] = 0;
  proc_table[p].status = SLEEP;
}

static int RR2_guest_create(LEVEL l, PID p, TASK_MODEL *m)
{ kern_raise(XINVALID_GUEST,exec_shadow); return 0; }

static void RR2_guest_detach(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR2_guest_dispatch(LEVEL l, PID p, int nostop)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR2_guest_epilogue(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR2_guest_activate(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR2_guest_insert(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR2_guest_extract(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR2_guest_endcycle(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR2_guest_end(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }

static void RR2_guest_sleep(LEVEL l, PID p)
{ kern_raise(XINVALID_GUEST,exec_shadow); }




/* Registration functions */

/*+ This init function install the "main" task +*/
static void RR2_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 aRR2ives
                                to the coRR2ect level */

  mb = ((RR2_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)
    printk("\nPanic!!! can't create main task...\n");

  RR2_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 RR2_register_level(TIME slice,
                       int createmain,
                       struct multiboot_info *mb)
{
  LEVEL l;            /* the level that we register */
  RR2_level_des *lev;  /* for readableness only */
  PID i;

  printk("RR2_register_level\n");

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

  /* alloc the space needed for the RR2_level_des */
  lev = (RR2_level_des *)kern_alloc(sizeof(RR2_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,  RR2_LEVELNAME, MAX_LEVELNAME);
  lev->l.level_code               = RR2_LEVEL_CODE;
  lev->l.level_version            = RR2_LEVEL_VERSION;

  lev->l.level_accept_task_model  = RR2_level_accept_task_model;
  lev->l.level_accept_guest_model = RR2_level_accept_guest_model;
  lev->l.level_status             = RR2_level_status;
  lev->l.level_scheduler          = RR2_level_scheduler;
  lev->l.level_guarantee          = RR2_level_guarantee;

  lev->l.task_create              = RR2_task_create;
  lev->l.task_detach              = RR2_task_detach;
  lev->l.task_eligible            = RR2_task_eligible;
  lev->l.task_dispatch            = RR2_task_dispatch;
  lev->l.task_epilogue            = RR2_task_epilogue;
  lev->l.task_activate            = RR2_task_activate;
  lev->l.task_insert              = RR2_task_insert;
  lev->l.task_extract             = RR2_task_extract;
  lev->l.task_endcycle            = RR2_task_endcycle;
  lev->l.task_end                 = RR2_task_end;
  lev->l.task_sleep               = RR2_task_sleep;

  lev->l.guest_create             = RR2_guest_create;
  lev->l.guest_detach             = RR2_guest_detach;
  lev->l.guest_dispatch           = RR2_guest_dispatch;
  lev->l.guest_epilogue           = RR2_guest_epilogue;
  lev->l.guest_activate           = RR2_guest_activate;
  lev->l.guest_insert             = RR2_guest_insert;
  lev->l.guest_extract            = RR2_guest_extract;
  lev->l.guest_endcycle           = RR2_guest_endcycle;
  lev->l.guest_end                = RR2_guest_end;
  lev->l.guest_sleep              = RR2_guest_sleep;

  /* fill the RR2 descriptor part */
  for (i = 0; i < MAX_PROC; i++)
    lev->nact[i] = -1;

  iq_init(&lev->ready, &freedesc, 0);

  if (slice < RR2_MINIMUM_SLICE) slice = RR2_MINIMUM_SLICE;
  if (slice > RR2_MAXIMUM_SLICE) slice = RR2_MAXIMUM_SLICE;
  lev->slice      = slice;

  lev->multiboot  = mb;

  if (createmain)
    sys_atrunlevel(RR2_call_main,(void *) l, RUNLEVEL_INIT);
}