incubator-nuttx/mm/mm_gran/mm_granmark.c

122 lines
3.4 KiB
C

/****************************************************************************
* mm/mm_gran/mm_granmark.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <assert.h>
#include <nuttx/mm/gran.h>
#include "mm_gran/mm_gran.h"
#ifdef CONFIG_GRAN
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: gran_mark_allocated
*
* Description:
* Mark a range of granules as allocated.
*
* Input Parameters:
* priv - The granule heap state structure.
* alloc - The address of the allocation.
* ngranules - The number of granules allocated
*
* Returned Value:
* On success, a non-NULL pointer to the allocated memory is returned;
* NULL is returned on failure.
*
****************************************************************************/
FAR void *gran_mark_allocated(FAR struct gran_s *priv, uintptr_t alloc,
unsigned int ngranules)
{
unsigned int granno;
unsigned int gatidx;
unsigned int gatbit;
unsigned int avail;
uint32_t gatmask;
/* Determine the granule number of the allocation */
granno = (alloc - priv->heapstart) >> priv->log2gran;
/* Determine the GAT table index associated with the allocation */
gatidx = granno >> 5;
gatbit = granno & 31;
/* Mark bits in the GAT entry or entries */
avail = 32 - gatbit;
if (ngranules > avail)
{
uint32_t gatmask2;
gatmask = 0xffffffff << gatbit;
ngranules -= avail;
gatmask2 = 0xffffffff >> (32 - ngranules);
/* Check that the area is free, from both mask words */
if (((priv->gat[gatidx] & gatmask) != 0) ||
((priv->gat[gatidx + 1] & gatmask2) != 0))
{
return NULL;
}
/* Mark bits in the first and second GAT entry */
priv->gat[gatidx] |= gatmask;
priv->gat[gatidx + 1] |= gatmask2;
}
/* Handle the case where where all of the granules come from one entry */
else
{
gatmask = 0xffffffff >> (32 - ngranules);
gatmask <<= gatbit;
/* Check that the area is free */
if ((priv->gat[gatidx] & gatmask) != 0)
{
return NULL;
}
/* Mark bits in a single GAT entry */
priv->gat[gatidx] |= gatmask;
}
return (FAR void *)alloc;
}
#endif /* CONFIG_GRAN */