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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: descr.h,v 1.3 2003-01-07 17:12:19 pj Exp $

 File:        $File$

 Revision:    $Revision: 1.3 $

 Last update: $Date: 2003-01-07 17:12:19 $

 ------------

Kernel main data structures

This file declare:

- the descriptors

  - cleanup handlers

  - levels

  - mutexes

  - mutex attributes

  - resource levels

**/

/*

 * 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

 *

 */

#ifndef __KERNEL_DESCR_H__

#define __KERNEL_DESCR_H__

#include <ll/ll.h>

#include <kernel/model.h>

#include <kernel/types.h>

#include <kernel/iqueue.h>

#include <limits.h>

/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

  CLEANUP HANDLER STRUCTURES

  Derived directly from posix standard, B.18.2.3

  This structure implements the task cleanup functions queue...

  look at kern.c!

  +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

struct _task_handler_rec {

  void (*f)(void *);

  void *a;

  struct _task_handler_rec *next;

};

struct condition_struct;

/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

  GENERAL TASK DESCRIPTOR

  In this type definition there is all the basic information for

  handling a task in the system.

  All the informations scheduler-dependent (like deadline, priority,

  and so on) are put in the level module files.

  In any case, a priority field is inserted to simplify the implementation

  of most of the scheduling algorithms

  +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

typedef struct {

        DWORD   task_ID;      /*+ progressive task counter ID +*/

        LEVEL   task_level;   /*+ the "real" level that owns the task     +*/

        CONTEXT context;      /*+ Context area pointer (see vm.h)         +*/

        BYTE    *stack;       /*+ Pointer to stack area base              +*/

        TASK    (*body)();    /*+ Pointer to the code of the task

                                  (starting address)                      +*/

        char    name[MAX_TASKNAME]; /*+ Text identifing the process name  +*/

        WORD    status;       /*+ actual task status

                                  (it could be EXE, SLEEP, IDLE, ...)     +*/

        WORD    pclass;       /*+ The code number of the task model used  +*/

        WORD    group;        /*+ 0 if task is single, else group id      +*/

        WORD    stacksize;    /*+ Task stack size                         +*/

        DWORD   control;      /*+ Control task operating mode

                                 Refer to the TASK_MODEL type for its use +*/

        int     frozen_activations; /*+ number of frozen activation;

                                        see kern.c, task_block_activations

                                        see model.h,flag in control field +*/

        /* sigset_t!!! */

        int sigmask;          /*+ The task signal mask                    +*/

        int sigpending;       /*+ The signal pending mask                 +*/

        int sigwaiting;       /*+ The signal waiting mask                 +*/

        int     avail_time;   /*+ the time the task can execute before a

                                  timer fire. see also the control field

                                  and bits related in model.h             +*/

        PID     shadow;       /*+ Shadow task                             +*/

        struct _task_handler_rec *cleanup_stack;

                              /*+ The cleanup stack                       +*/

        int     errnumber;

        /* Job Execution Time fields */

        TIME    jet_table[JET_TABLE_DIM];

                              /*+ Execution time of the last

                                  activations of the task.                +*/

        int     jet_tvalid;   /*+ number of valid entry in the jet_table  +*/

        int     jet_curr;     /*+ Current entry in the jet_table          +*/

        TIME    jet_max;      /*+ Maximum Execution time since task_create

                                  or last jet_delstat                     +*/

        TIME    jet_sum;      /*+ Mean Execution time since task_create

                                  or last jet_delstat                     +*/

        TIME    jet_n;        /*+ Number of instances on witch the mean

                                  time have to be computed                +*/

        /* task_join fields */

        PID waiting_for_me;   /*+ the task that waits my dead,

                                  NIL if there aren't                     +*/

        void *return_value;   /*+ task return value                       +*/

        /* task specific data (it uses directly POSIX constant) */

        void *keys[PTHREAD_KEYS_MAX];

        /* condition variable field */

        struct condition_struct *cond_waiting;

                              /*+ the condition on that the task is

                                  waiting +*/

        /* stuff used in most algorithms; they are not used directly in

         * the generic kernel, with exclusion of delay_timer that is used

         * also in cond_timedwait

         */

        int     delay_timer;  /*+ A field useful to store the delay timer +*/

        int     wcet;         /*+ a worst case time execution             +*/

} proc_des;

/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

  LEVEL DESCRIPTOR

  In this type definition there is all the basic information for

  handling a scheduling level in the system.

  All the informations that depends on the particular module are put

  in the level module files.

  Here a small description of the various functions:

  -------------------------------------------------------------------

  - PUBLIC Functions:

    on one side, a module should export an interface to the Generic

    Kernel, giving a set of functions that the Generic Kernel can use

    to ask a service to the module. That is, the Public Functions are

    called ONLY by the Generic Kernel.

  - PRIVATE Functions: on the other side, a module can export an

    interface to the public part of the same or of another

    module. That is, Private Functions are called ONLY by Public and

    Private Functions.

  -------------------------------------------------------------------

  int  (*private_insert  )(LEVEL l, PID p, TASK_MODEL *m);

  Inserts a task into the internal module data structure.

  void (*private_extract )(LEVEL l, PID p);

  Removes a task from the internal module data structure.

  int  (*private_eligible)(LEVEL l, PID p);

  A task inserted into the internal module data structure needs to be

  scheduled. returns 0 if it can be scheduled, -1 if not.

  void (*private_dispatch)(LEVEL l, PID p, int nostop);

  A task inserted into the internal module data structure has been dispatched.

  void (*private_epilogue)(LEVEL l, PID p);

  A task inserted into the internal module data structure has been preempted.

  PID  (*public_scheduler)(LEVEL l);

  returns a task to schedule, or -1 if no tasks are ready

  int  (*public_guarantee)(LEVEL l, bandwidth_t *freebandwidth);

  returns 0 if the level is guaranteed, -1 if not

  no guarantee if (*f)()=null

  the function updates the parameter freebandwidth (see guarantee() )                  

  int  (*public_create   )(LEVEL l, PID p, TASK_MODEL *m);

  the task p is created into the module

  returns 0->ok, -1->error

  void (*public_detach )(LEVEL l, PID p);

  there is an error in the public_create. The function removes all the

  informations about the task in the module.

  void (*public_end      )(LEVEL l, PID p);

  the task has been killed, or it ended regularly

  int  (*public_eligible )(LEVEL l, PID p);

  A task needs to be scheduled. returns 0 if it can be scheduled, -1 if not.

  void (*public_dispatch )(LEVEL l, PID p, int nostop);

  A task has been dispatched.

  void (*public_epilogue )(LEVEL l, PID p);

  A task has been preempted (or its capacity is exausted).

  void (*public_activate )(LEVEL l, PID p);

  A task has been activated.

  void (*public_unblock  )(LEVEL l, PID p);

  void (*public_block    )(LEVEL l, PID p);

  A task has been unblocked/blocked on a synchronization point

  (e.g. a semaphore, a mailbox, a nanosleep).

  int (*public_message  )(LEVEL l, PID p, void *m);

  A task sent a message m to the module.

  If the message has value NULL the

  behavior should be the task_endcycle primitive behavior.

  The function returns an integer to the user.

  If you want to avoid the call to public_epilogue, after public_message,

  just write exec = exec_shadow = -1; in your public_message code.

  +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

typedef struct {

  void (*private_insert  )(LEVEL l, PID p, TASK_MODEL *m);

  void (*private_extract )(LEVEL l, PID p);

  int  (*private_eligible)(LEVEL l, PID p);

  void (*private_dispatch)(LEVEL l, PID p, int nostop);

  void (*private_epilogue)(LEVEL l, PID p);

  PID  (*public_scheduler)(LEVEL l);

  int  (*public_guarantee)(LEVEL l, bandwidth_t *freebandwidth);

  int  (*public_create   )(LEVEL l, PID p, TASK_MODEL *m);

  void (*public_detach   )(LEVEL l, PID p);

  void (*public_end      )(LEVEL l, PID p);

  int  (*public_eligible )(LEVEL l, PID p);

  void (*public_dispatch )(LEVEL l, PID p, int nostop);

  void (*public_epilogue )(LEVEL l, PID p);

  void (*public_activate )(LEVEL l, PID p);

  void (*public_unblock  )(LEVEL l, PID p);

  void (*public_block    )(LEVEL l, PID p);

  int  (*public_message  )(LEVEL l, PID p, void *m);

} level_des;

/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

  RESOURCE DESCRIPTOR

  In this type definition there is all the basic information for

  handling a resource module in the system.

  All the informations protocol-dependent (like ceiling, task that use

  a particular resource, and so on) are put in the resource module files.

  In general, the initialization of a resource module is splitted in two

  parts:

  - the registration   -> tipically done with a finction called

                          XXX_register_module. It is called before the

                          system initialization, in

                          the function __kernel_register_levels__().

  - the initialization -> called during the system initialization,

                          This is done posting some init functions with

                          the sys_at_init()

  +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

typedef struct {

  int rtype;                    /*+ resource module extented interface

                                    code (see model.h)                   +*/

  int (*res_register)(RLEVEL l, PID p, RES_MODEL *r);

                                /*+ When the system knows that a

                                    resource model can be registered

                                    by a level, it calls this

                                    function. It registers all the

                                    information about the task and the

                                    model. returns 0 if the model

                                    can be handled, -1 otherwise+*/

  void (*res_detach)(RLEVEL l, PID p);

                                /*+ this function is called when the task

                                    is killed or some error is occurred

                                    in the task_create. It have to unlink

                                    the task from the module... If the task

                                    is already unlinked from the protocol

                                    no action is done                    +*/

} resource_des;

/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

  MUTEX DESCRIPTOR

  In this type definition there is all the basic fields for

  handling a mutex in the system

  Many of the informations protocol-dependent (like ceiling, and so on)

  are put in the resource module or are pointef by the field opt.

  The opt field is used because in this way a mutex can be allocated in

  a dynamic way (in this case opt points to a dynamically allocated

  structure) or in a static way (in this case opt can be an index or a

  pointer to a static structure)

  +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

typedef struct {

  RLEVEL mutexlevel;  /*+ protocol used by the mutex. +*/

  int use;            /*+ the mutex is used in a condition wait... +*/

  void *opt;

} mutex_t;

/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

  MUTEX RESOURCE DESCRIPTOR

  This object is a resource_des object with a set of functions used to

  implement the mutex behaviour.

  +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

typedef struct {

  resource_des r;

  int (*init)   (RLEVEL l, mutex_t *m, const mutexattr_t *a);

    /*+ this function is called when a mutex is created. it returns

        >=0 if the mutexattr_t can be managed by the level (=0 Ok, an

        error otherwise), -1 otherwise +*/

  int (*destroy)(RLEVEL l, mutex_t *m);

  int (*lock)   (RLEVEL l, mutex_t *m);

  int (*trylock)(RLEVEL l, mutex_t *m);

  int (*unlock) (RLEVEL l, mutex_t *m);

} mutex_resource_des;

/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

  CONDITION VARIABLE DESCRIPTOR

  This is the condition variable descriptor.

  +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

typedef struct condition_struct {

  IQUEUE waiters; /*+ queue for tasks waiting on the condition +*/

  mutex_t *used_for_waiting;

} cond_t;

#endif /* __TYPE_H__ */