103 lines
3.2 KiB
C
103 lines
3.2 KiB
C
/****************************************************************************
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* mm/mm_gran/mm_granreserve.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <assert.h>
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#include <nuttx/mm/gran.h>
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#include "mm_gran/mm_gran.h"
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#ifdef CONFIG_GRAN
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: gran_reserve
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*
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* Description:
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* Reserve memory in the granule heap. This will reserve the granules
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* that contain the start and end addresses plus all of the granules
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* in between. This should be done early in the initialization sequence
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* before any other allocations are made.
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*
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* Reserved memory can never be allocated (it can be freed however which
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* essentially unreserves the memory).
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*
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* Input Parameters:
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* handle - The handle previously returned by gran_initialize
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* start - The address of the beginning of the region to be reserved.
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* size - The size of the region to be reserved
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*
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* Returned Value:
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* On success, a non-NULL pointer to the allocated memory is returned;
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* NULL is returned on failure.
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*
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****************************************************************************/
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FAR void *gran_reserve(GRAN_HANDLE handle, uintptr_t start, size_t size)
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{
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FAR struct gran_s *priv = (FAR struct gran_s *)handle;
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FAR void *ret = NULL;
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DEBUGASSERT(priv != NULL);
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if (size > 0)
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{
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uintptr_t mask = (1 << priv->log2gran) - 1;
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uintptr_t end = start + size - 1;
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unsigned int ngranules;
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/* Get the aligned (down) start address and the aligned (up) end
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* address
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*/
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start &= ~mask;
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end = (end + mask) & ~mask;
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/* Calculate the new size in granules */
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ngranules = ((end - start) >> priv->log2gran) + 1;
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/* Must lock the granule allocator */
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if (gran_enter_critical(priv) < 0)
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{
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return NULL;
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}
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/* And reserve the granules */
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ret = gran_mark_allocated(priv, start, ngranules);
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gran_leave_critical(priv);
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}
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return ret;
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}
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#endif /* CONFIG_GRAN */
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