nuttx/sched/mq_internal.h

/************************************************************
 * mq_internal.h
 *
 *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name Gregory Nutt nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ************************************************************/

#ifndef __MQ_INTERNAL_H
#define __MQ_INTERNAL_H

/************************************************************
 * Included Files
 ************************************************************/

#include <sys/types.h>
#include <mqueue.h>
#include <sched.h>
#include <signal.h>
#include <nuttx/compiler.h>

/************************************************************
 * Compilations Switches
 ************************************************************/

/************************************************************
 * Definitions
 ************************************************************/

#define MQ_MAX_BYTES   CONFIG_MQ_MAXMSGSIZE
#define MQ_MAX_HWORDS  ((MQ_MAX_BYTES + sizeof(uint16) - 1) / sizeof(uint16))
#define MQ_MAX_MSGS    16
#define MQ_PRIO_MAX    255

/* This defines the number of messages descriptors to allocate
 * at each "gulp."
 */

#define NUM_MSG_DESCRIPTORS 24

/* This defines the number of messages to set aside for
 * exclusive use by interrupt handlers
 */

#define NUM_INTERRUPT_MSGS   8

/************************************************************
 * Global Type Declarations
 ************************************************************/

enum mqalloc_e
{
  MQ_ALLOC_FIXED = 0,  /* pre-allocated; never freed */
  MQ_ALLOC_DYN,        /* dynamically allocated; free when unused */
  MQ_ALLOC_IRQ         /* Preallocated, reserved for interrupt handling */
};
typedef enum mqalloc_e mqalloc_t;

/* This structure describes one buffered POSIX message. */
/* NOTE:  This structure is allocated from the same pool as MQ_type.
 * Therefore, (1) it must have a fixed "mail" size, and (2) must
 * exactly match MQ_type in size.
 */

struct mqmsg
{
  /* The position of the following two field must exactly match
   * MQ_type.
   */

  FAR struct mqmsg  *next;    /* Forward link to next message */
  ubyte        type;          /* (Used to manage allocations) */

  ubyte        priority;      /* priority of message          */
  ubyte        msglen;        /* Message data length          */
  uint16       mail[MQ_MAX_HWORDS]; /* Message data           */
};
typedef struct mqmsg mqmsg_t;

/* This structure defines a message queue */

struct mq_des; /* forward reference */

struct msgq_s
{
  FAR struct msgq_s *flink;   /* Forward link to next message queue */
  sq_queue_t   msglist;       /* Prioritized message list */
  sint16       maxmsgs;       /* Maximum number of messages in the queue */
  sint16       nmsgs;         /* Number of message in the queue */
  sint16       nconnect;      /* Number of connections to message queue */
  sint16       nwaitnotfull;  /* Number tasks waiting for not full */
  sint16       nwaitnotempty; /* Number tasks waiting for not empty */
  ubyte        maxmsgsize;    /* Max size of message in message queue */
  boolean      unlinked;      /* TRUE if the msg queue has been unlinked */
  FAR struct mq_des *ntmqdes; /* Notification: Owning mqdes (NULL if none) */
  pid_t        ntpid;         /* Notification: Receiving Task's PID */
  int          ntsigno;       /* Notification: Signal number */
  union sigval ntvalue;       /* Notification: Signal value */
  char         name[1];       /* Start of the queue name */
};

#define SIZEOF_MQ_HEADER ((int)(((msgq_t*)NULL)->name))

/* This describes the message queue descriptor that is held in the
 * task's TCB
 */

struct mq_des
{
  FAR struct mq_des *flink;   /* Forward link to next message descriptor */
  FAR msgq_t  *msgq;          /* Pointer to associated message queue */
  int          oflags;        /* Flags set when message queue was opened */
};

/************************************************************
 * Global Variables
 ************************************************************/

/* This is a list of all opened message queues */

extern sq_queue_t  g_msgqueues;

/* The g_msgfree is a list of messages that are available
 * for general use.  The number of messages in this list is a
 * system configuration item.
 */

extern sq_queue_t  g_msgfree;

/* The g_msgfreeInt is a list of messages that are reserved
 * for use by interrupt handlers.
 */

extern sq_queue_t  g_msgfreeirq;

/* The g_desfree data structure is a list of message
 * descriptors available to the operating system for general use.
 * The number of messages in the pool is a constant.
 */

extern sq_queue_t  g_desfree;

/************************************************************
 * Global Function Prototypes
 ************************************************************/

#ifdef __cplusplus
#define EXTERN extern "C"
extern "C" {
#else
#define EXTERN extern
#endif

/* Functions defined in mq_initialized.c *******************/

EXTERN void weak_function mq_initialize(void);
EXTERN void        mq_desblockalloc(void);

EXTERN mqd_t       mq_descreate(FAR _TCB* mtcb, FAR msgq_t* msgq, int oflags);
EXTERN FAR msgq_t *mq_findnamed(const char *mq_name);
EXTERN void        mq_msgfree(FAR mqmsg_t *mqmsg);
EXTERN void        mq_msgqfree(FAR msgq_t *msgq);

#undef EXTERN
#ifdef __cplusplus
}
#endif

#endif /* __MQ_INTERNAL_H */