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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 1.1.1.1 2002-03-29 14:12:52 pj Exp $

 File:        $File$
 Revision:    $Revision: 1.1.1.1 $
 Last update: $Date: 2002-03-29 14:12:52 $
 ------------

 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
#define RR_DELAY   MODULE_STATUS_BASE+1

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

  QQUEUE 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";
    case RR_DELAY: return "RR_Delay";
    default      : return "RR_Unknown";
  }
}

/*+ this function is called when a task finish his delay +*/
static void RR_timer_delay(void *par)
{
  PID p = (PID) par;
  RR_level_des *lev;

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

  proc_table[p].status = RR_READY;
  qq_insertlast(p,&lev->ready);

  proc_table[p].delay_timer = NIL;  /* Paranoia */

//  kern_printf(" DELAY TIMER %d ", p);

  event_need_reschedule();
}


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 = qq_queryfirst(&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 = proc_table[p].next;
  }

  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 = qq_queryfirst(&lev->ready);
    if (p == -1)
      return p;

    if (proc_table[p].avail_time <= 0) {
      proc_table[p].avail_time += proc_table[p].wcet;
      qq_extract(p,&lev->ready);
      qq_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 */
}

#ifdef __TEST1__
extern int testactive;
extern struct timespec s_stime[];
extern TIME s_curr[];
extern TIME s_PID[];
extern int useds;
#endif

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!!! */
  qq_extract(p, &lev->ready);


  #ifdef __TEST1__
  if (testactive)
  {
    TIMESPEC_ASSIGN(&s_stime[useds],&schedule_time);
    s_curr[useds] = proc_table[p].avail_time;
    s_PID[useds]  = p;
    useds++;
  }
  #endif
//  if (nostop) kern_printf("Û");
//  kern_printf("(RR d %d)",nostop);
}

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;
    qq_insertlast(p,&lev->ready);
  }
  else
    /* curr is >0, so the running task have to run for another curr usec */
    qq_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;
  qq_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;
  qq_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;
  q_insert(p,&freedesc);
}

static void RR_task_sleep(LEVEL l, PID p)
{
  proc_table[p].status = SLEEP;
}

static void RR_task_delay(LEVEL l, PID p, TIME usdelay)
{
//  RR_level_des *lev = (RR_level_des *)(level_table[l]);
  struct timespec wakeuptime;

  /* equal to RR_task_endcycle */
  proc_table[p].status = RR_DELAY;

  /* we need to delete this event if we kill the task while it is sleeping */
  ll_gettime(TIME_EXACT,&wakeuptime);
  ADDUSEC2TIMESPEC(usdelay,&wakeuptime);
  proc_table[p].delay_timer = kern_event_post(&wakeuptime,
                                              RR_timer_delay,
                                              (void *)p);
}


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

static void RR_guest_detach(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

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

static void RR_guest_epilogue(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void RR_guest_activate(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void RR_guest_insert(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void RR_guest_extract(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void RR_guest_endcycle(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void RR_guest_end(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void RR_guest_sleep(LEVEL l, PID p)
{ kern_raise(XUNVALID_GUEST,exec_shadow); }

static void RR_guest_delay(LEVEL l, PID p,DWORD tickdelay)
{ kern_raise(XUNVALID_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.task_delay               = RR_task_delay;

  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;
  lev->l.guest_delay              = RR_guest_delay;

  /* fill the RR descriptor part */
  qq_init(&lev->ready);

  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);
}