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/*
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 * Project: S.Ha.R.K.
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 *
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 * Coordinators:
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 *   Giorgio Buttazzo    <giorgio@sssup.it>
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 *   Paolo Gai           <pj@gandalf.sssup.it>
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 *
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 * Authors     :
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 *   Paolo Gai           <pj@gandalf.sssup.it>
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 *   Massimiliano Giorgi <massy@gandalf.sssup.it>
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 *   Luca Abeni          <luca@gandalf.sssup.it>
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 *   (see the web pages for full authors list)
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 *
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 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
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 *
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 * http://www.sssup.it
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 * http://retis.sssup.it
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 * http://shark.sssup.it
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 */
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/**
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 ------------
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 CVS :        $Id: nopm.c,v 1.1 2005-02-25 10:55:09 pj Exp $
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 File:        $File$
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 Revision:    $Revision: 1.1 $
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 Last update: $Date: 2005-02-25 10:55:09 $
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 ------------
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 See modules/nopm.h.
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 This code is a copy of nop.c with minor modifications.
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**/
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/*
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 * Copyright (C) 2000 Massimiliano Giorgi
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 *
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 */
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#include <nopm/nopm/nopm.h>
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#include <ll/ll.h>
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#include <ll/stdio.h>
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#include <ll/string.h>
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#include <kernel/const.h>
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#include <sys/types.h>
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#include <kernel/descr.h>
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#include <kernel/var.h>
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#include <kernel/func.h>
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/* The NOPM resource level descriptor */
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typedef struct {
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  mutex_resource_des m;   /*+ the mutex interface +*/
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} NOPM_mutex_resource_des;
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/* this is the structure normally pointed by the opt field in the
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   mutex_t structure */
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typedef struct {
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  PID owner;
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  IQUEUE blocked;
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  int counter;
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} NOPM_mutex_t;
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#define MAXTABLE 4096
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static mutex_t *table[MAXTABLE];
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static int index=0;
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static int register_nopm(mutex_t *p)
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{
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  if (index>=MAXTABLE) return -1;
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  table[index++]=p;
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  return 0;
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}
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void dump_nopm_table(void)
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{
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  NOPM_mutex_t *ptr;
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  SYS_FLAGS f;
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  PID j;
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  int i;
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  f=kern_fsave();
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  kern_printf("nopm_mutex module TABLE\n");
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  kern_printf("----------------------\n");
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  for(i=0;i<index;i++) {
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    ptr=table[i]->opt;
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    if (!iq_isempty(&ptr->blocked)) {
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      kern_printf("%i blocks on 0x%p: ",ptr->owner,table[i]);
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      j=iq_query_first(&ptr->blocked);
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      while (j!=NIL) {
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        kern_printf("%i ",(int)j);
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        j=iq_query_next(j, &ptr->blocked);
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      }
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      kern_printf("\n");
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    } else {
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      //kern_printf("0x%p no block\n",table[i]);
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    }      
121
  }
122
  kern_frestore(f);
123
 
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}
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/* Wait status for this library */
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#define NOPM_WAIT LIB_STATUS_BASE
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static int NOPM_res_register(RLEVEL l, PID p, RES_MODEL *r)
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{
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  return -1;
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}
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static void NOPM_res_detach(RLEVEL l, PID p)
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{
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}
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static int NOPM_init(RLEVEL l, mutex_t *m, const mutexattr_t *a)
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{
152
  NOPM_mutex_t *p;
153
 
154
  if (a->mclass != NOPM_MCLASS)
155
    return -1;
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157
  p = (NOPM_mutex_t *) kern_alloc(sizeof(NOPM_mutex_t));
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  /* control if there is enough memory; no control on init on a
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     non- destroyed mutex */
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162
  if (!p)
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    return (ENOMEM);
164
 
165
  p->owner = NIL;
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  iq_init(&p->blocked, &freedesc, 0);
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  p->counter=0;
168
 
169
  m->mutexlevel = l;
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  m->opt = (void *)p;
171
 
172
  /* MG */
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  register_nopm(m);
174
 
175
  return 0;
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}
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static int NOPM_destroy(RLEVEL l, mutex_t *m)
180
{
181
//  NOPM_mutex_resource_des *lev = (NOPM_mutex_resource_des *)(resource_table[l]);
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  SYS_FLAGS f;
183
 
184
  if ( ((NOPM_mutex_t *)m->opt)->owner != NIL)
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    return (EBUSY);
186
 
187
  f = kern_fsave();
188
  if (m->opt) {
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    kern_free(m->opt,sizeof(NOPM_mutex_t));
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    m->opt = NULL;
191
  }
192
  kern_frestore(f);
193
 
194
  return 0;
195
}
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197
static int NOPM_lock(RLEVEL l, mutex_t *m)
198
{
199
  NOPM_mutex_t *p;
200
  SYS_FLAGS f;
201
 
202
  f = kern_fsave();
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204
  p = (NOPM_mutex_t *)m->opt;
205
  if (!p) {
206
    /* if the mutex is not initialized, initialize it! */
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    NOPM_mutexattr_t a;
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    NOPM_mutexattr_default(a);
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    NOPM_init(l, m, &a);
210
  }
211
 
212
  if (p->owner == exec_shadow) {
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    /* the task already owns the mutex */
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    p->counter++;
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    kern_frestore(f);
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    return 0;
217
  }
218
 
219
  if (p->owner != NIL)  {           /* We must block exec task   */
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       LEVEL l;            /* for readableness only */
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       proc_table[exec_shadow].context = kern_context_save();
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       kern_epilogue_macro();
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       l = proc_table[exec_shadow].task_level;
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       level_table[l]->public_block(l,exec_shadow);
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       /* we insert the task in the semaphore queue */
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       proc_table[exec_shadow].status = NOPM_WAIT;
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       iq_insertlast(exec_shadow,&p->blocked);
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       /* and finally we reschedule */
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       exec = exec_shadow = -1;
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       scheduler();
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       kern_context_load(proc_table[exec_shadow].context);            
236
  }
237
  else {
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    /* the mutex is free, We can lock it! */
239
    p->owner = exec_shadow;
240
    p->counter++;
241
    kern_frestore(f);
242
  }
243
 
244
  return 0;
245
}
246
 
247
static int NOPM_trylock(RLEVEL l, mutex_t *m)
248
{
249
  NOPM_mutex_t *p;
250
  SYS_FLAGS f;
251
 
252
  f = kern_fsave();
253
 
254
  p = (NOPM_mutex_t *)m->opt;
255
  if (!p) {
256
    /* if the mutex is not initialized, initialize it! */
257
    NOPM_mutexattr_t a;
258
    NOPM_mutexattr_default(a);
259
    NOPM_init(l, m, &a);
260
  }
261
 
262
  if (p->owner != NIL)  {
263
    /* a task already owns the mutex */
264
    kern_frestore(f);
265
    return (EBUSY);
266
  }
267
  else {
268
    /* the mutex is free, We can lock it! */
269
    p->owner = exec_shadow;
270
    p->counter++;
271
    kern_frestore(f);
272
  }
273
 
274
  return 0;
275
}
276
 
277
static int NOPM_unlock(RLEVEL l, mutex_t *m)
278
{
279
  NOPM_mutex_t *p;
280
  PID e;
281
 
282
  p = (NOPM_mutex_t *)m->opt;
283
  if (!p)
284
    return (EINVAL);
285
 
286
  if (p->owner != exec_shadow) {
287
    /* the mutex is owned by another task!!! */
288
    kern_printf("wrongunlock<owner=%i,unlocker=%i>",p->owner,exec_shadow);
289
    kern_sti();
290
    return (EPERM);
291
  }
292
 
293
  p->counter--;
294
  if (p->counter!=0) {
295
    /* we have multiple lock on this mutex */
296
    kern_sti();
297
    return 0;
298
  }
299
 
300
  proc_table[exec_shadow].context = kern_context_save();
301
 
302
  /* the mutex is mine, pop the firsttask to extract */
303
  for (;;) {
304
    e = iq_getfirst(&p->blocked);
305
    if (e == NIL) {
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      p->owner = NIL;
307
      break;
308
    } else if (proc_table[e].status == NOPM_WAIT) {
309
      l = proc_table[e].task_level;
310
      level_table[l]->public_unblock(l,e);
311
      p->counter++;
312
      break;
313
    }
314
  }
315
 
316
  /* MG!!! */
317
  p->owner = e;
318
 
319
  scheduler();
320
  kern_context_load(proc_table[exec_shadow].context);
321
 
322
  return 0;
323
}
324
 
325
RLEVEL NOPM_register_module(void)
326
{
327
  RLEVEL l;                  /* the level that we register */
328
  NOPM_mutex_resource_des *m;  /* for readableness only */
329
 
330
  printk("NOPM_register_module\n");
331
 
332
  /* request an entry in the level_table */
333
  l = resource_alloc_descriptor();
334
 
335
  /* alloc the space needed for the EDF_level_des */
336
  m = (NOPM_mutex_resource_des *)kern_alloc(sizeof(NOPM_mutex_resource_des));
337
 
338
  /* update the level_table with the new entry */
339
  resource_table[l] = (resource_des *)m;
340
 
341
  /* fill the resource_des descriptor */
342
  m->m.r.rtype                       = MUTEX_RTYPE;
343
  m->m.r.res_register                = NOPM_res_register;
344
  m->m.r.res_detach                  = NOPM_res_detach;
345
 
346
  /* fill the mutex_resource_des descriptor */
347
  m->m.init                          = NOPM_init;
348
  m->m.destroy                       = NOPM_destroy;
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  m->m.lock                          = NOPM_lock;
350
  m->m.trylock                       = NOPM_trylock;
351
  m->m.unlock                        = NOPM_unlock;
352
 
353
  return l;
354
}
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