source: rtems/cpukit/include/rtems/rtems/region.h @ 2afb22b

/**
 * @file rtems/rtems/region.h
 *
 * @defgroup ClassicRegion Regions
 *
 * @ingroup ClassicRTEMS
 * @brief Region Manager
 *
 * This include file contains all the constants and structures associated
 * with the Region Manager. This manager provides facilities to dynamically
 * allocate memory in variable sized units which are returned as segments.
 *
 * Directives provided are:
 *
 * - create a region
 * - get an ID of a region
 * - delete a region
 * - get a segment from a region
 * - return a segment to a region
 */

/* COPYRIGHT (c) 1989-2013.
 * On-Line Applications Research Corporation (OAR).
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rtems.org/license/LICENSE.
 */

#ifndef _RTEMS_RTEMS_REGION_H
#define _RTEMS_RTEMS_REGION_H

#include <rtems/rtems/attr.h>
#include <rtems/rtems/options.h>
#include <rtems/rtems/status.h>
#include <rtems/rtems/types.h>
#include <rtems/score/heap.h>
#include <rtems/score/threadq.h>

#ifdef __cplusplus
extern "C" {
#endif

/**
 *  @defgroup ClassicRegion Regions
 *
 *  @ingroup ClassicRTEMS
 *
 *  This encapsulates functionality related to the Classic API Region
 *  Manager.
 */
/**@{*/

/**
 *  The following records define the control block used to manage
 *  each region.
 */

typedef struct {
  Objects_Control       Object;
  Thread_queue_Control  Wait_queue;            /* waiting threads        */
  const Thread_queue_Operations *wait_operations;
  uintptr_t             maximum_segment_size;  /* in bytes               */
  rtems_attribute       attribute_set;
  Heap_Control          Memory;
}  Region_Control;

/**
 *  @brief rtems_region_create
 *
 *  Region Manager
 *
 *  This routine implements the rtems_region_create directive.  The
 *  region will have the name name.  The memory area managed by
 *  the region is of length bytes and starts at starting_address.
 *  The memory area will be divided into as many allocatable units of
 *  page_size bytes as possible.   The attribute_set determines which
 *  thread queue discipline is used by the region.  It returns the
 *  id of the created region in ID.
 */
rtems_status_code rtems_region_create(
  rtems_name          name,
  void               *starting_address,
  uintptr_t           length,
  uintptr_t           page_size,
  rtems_attribute     attribute_set,
  rtems_id           *id
);

/**
 * @brief RTEMS Extend Region
 *
 * This routine implements the rtems_region_extend directive. The
 * region will have the name name. The memory area managed by
 * the region will be attempted to be grown by length bytes using
 * the memory starting at starting_address.
 *
 * @param[in] id is the id of region to grow
 * @param[in] starting_address starting address of memory area for extension
 * @param[in] length is the physical length in bytes to grow the region
 *
 * @retval This method returns RTEMS_SUCCESSFUL if there was not an
 *         error. Otherwise, a status code is returned indicating the
 *         source of the error.
 */
rtems_status_code rtems_region_extend(
  rtems_id            id,
  void               *starting_address,
  uintptr_t           length
);

/**
 * @brief RTEMS Region Name to Id
 *
 * This routine implements the rtems_region_ident directive.
 * This directive returns the region ID associated with name.
 * If more than one region is named name, then the region
 * to which the ID belongs is arbitrary.
 *
 * @param[in] name is the user defined region name
 * @param[in] id is the pointer to region id
 *
 * @retval This method returns RTEMS_SUCCESSFUL if there was not an
 *         error. Otherwise, a status code is returned indicating the
 *         source of the error. If successful, the id will
 *         be filled in with the region id.
 */
rtems_status_code rtems_region_ident(
  rtems_name    name,
  rtems_id     *id
);

/**
 * @brief RTEMS Get Region Information
 *
 * This routine implements the rtems_region_get_information directive.
 * This directive returns information about the heap associated with
 * this region.
 *
 * @param[in] id is the region id
 * @param[in] the_info is the pointer to region information block
 *
 * @retval RTEMS_SUCCESSFUL if successful or error code if unsuccessful and
 * *id filled with the region information block
 */
rtems_status_code rtems_region_get_information(
  rtems_id                id,
  Heap_Information_block *the_info
);

/**
 * @brief RTEMS Get Region Free Information
 *
 * This routine implements the rtems_region_get_free_information directive.
 * This directive returns information about the free blocks in the
 * heap associated with this region. Information about the used blocks
 * will be returned as zero.
 *
 * @param[in] id is the region id
 * @param[in] the_info is the pointer to region information block
 *
 * @retval This method returns RTEMS_SUCCESSFUL if there was not an
 *         error. Otherwise, a status code is returned indicating the
 *         source of the error. If successful, the the_info will
 *         be filled in with the region information block.
 */
rtems_status_code rtems_region_get_free_information(
  rtems_id                id,
  Heap_Information_block *the_info
);

/**
 * @brief RTEMS Delete Region
 *
 * This routine implements the rtems_region_delete directive. The
 * region indicated by ID is deleted, provided that none of its segments are
 * still allocated.
 *
 * @param[in] id is the region id
 *
 * @retval This method returns RTEMS_SUCCESSFUL if there was not an
 *         error. Otherwise, a status code is returned indicating the
 *         source of the error.
 */
rtems_status_code rtems_region_delete(
  rtems_id   id
);

/**
 * @brief RTEMS Get Region Segment
 *
 * This routine implements the rtems_region_get_segment directive. It
 * attempts to allocate a segment from the region associated with @a id.
 * If a segment of the requested @a size size can be allocated, its address
 * is returned in @a segment. If no segment is available, then the task
 * may return immediately or block waiting for a segment with an optional
 * timeout of @a timeout clock ticks. Whether the task blocks or returns
 * immediately is based on the no_wait option in the @a option_set.
 *
 * @param[in] id is the region id
 * @param[in] size is the segment size in bytes
 * @param[in] option_set is the wait option
 * @param[in] timeout is the number of ticks to wait (0 means wait forever)
 * @param[in] segment is the pointer to segment address
 *
 * @retval This method returns RTEMS_SUCCESSFUL if there was not an
 *         error. Otherwise, a status code is returned indicating the
 *         source of the error. If successful, the segment will
 *         be filled in with the segment address.
 */
rtems_status_code rtems_region_get_segment(
  rtems_id           id,
  uintptr_t          size,
  rtems_option       option_set,
  rtems_interval     timeout,
  void             **segment
);

/**
 * @brief RTEMS Get Region Segment Size
 *
 * This routine implements the rtems_region_get_segment_size directive. It
 * returns the size in bytes of the specified user memory area.
 *
 * @param[in] id is the region id
 * @param[in] segment is the segment address
 * @param[in] size is the pointer to segment size in bytes
 *
 * @retval This method returns RTEMS_SUCCESSFUL if there was not an
 *         error. Otherwise, a status code is returned indicating the
 *         source of the error. If successful, the size will
 *         be filled in with the segment size in bytes.
 */
rtems_status_code rtems_region_get_segment_size(
  rtems_id           id,
  void              *segment,
  uintptr_t         *size
);

/**
 * @brief RTEMS Return Region Segment
 *
 * This routine implements the rtems_region_return_segment directive. It
 * frees the segment to the region associated with ID. The segment must
 * have been previously allocated from the same region. If freeing the
 * segment results in enough memory being available to satisfy the
 * rtems_region_get_segment of the first blocked task, then that task and as
 * many subsequent tasks as possible will be unblocked with their requests
 * satisfied.
 *
 * @param[in] id is the region id
 * @param[in] segment is the pointer to segment address
 *
 * @retval RTEMS_SUCCESSFUL if successful or error code if unsuccessful
 */
rtems_status_code rtems_region_return_segment(
  rtems_id    id,
  void       *segment
);

/**
 * @brief Resize RTEMS Region Segment
 *
 * This routine implements the rtems_region_resize_segment directive. It
 * tries to resize segment in the region associated with 'id' to the new size
 * 'size' in place. The first 'size' or old size bytes of the segment
 * (whatever is less) are guaranteed to remain unmodified. The segment must
 * have been previously allocated from the same region. If resizing the
 * segment results in enough memory being available to satisfy the
 * rtems_region_get_segment of the first blocked task, then that task and as
 * many subsequent tasks as possible will be unblocked with their requests
 * satisfied.
 *
 * @param[in] id is the region id
 * @param[in] segment is the pointer to segment address
 * @param[in] size is the new required size
 * @retval RTEMS_SUCCESSFUL if operation successful, RTEMS_UNSATISFIED if the
 *         the segment can't be resized in place or any other code at failure
 *
 * @note On RTEMS_SUCCESSFUL or RTEMS_UNSATISFIED exit it returns into the
 *       'old_size' the old size in bytes of the user memory area of the
 *       specified segment.
 */
rtems_status_code rtems_region_resize_segment(
  rtems_id    id,
  void       *segment,
  uintptr_t   size,
  uintptr_t  *old_size
);

/**@}*/

#ifdef __cplusplus
}
#endif

#endif
/* end of include file */