137 lines
3.9 KiB
C
137 lines
3.9 KiB
C
/****************************************************************************
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* mm/mm_gran/mm_granfree.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 <errno.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_free
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*
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* Description:
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* Return memory to the granule heap.
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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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* memory - A pointer to memory previoiusly allocated by gran_alloc.
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void gran_free(GRAN_HANDLE handle, FAR void *memory, 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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unsigned int granno;
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unsigned int gatidx;
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unsigned int gatbit;
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unsigned int granmask;
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unsigned int ngranules;
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unsigned int avail;
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uint32_t gatmask;
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int ret;
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DEBUGASSERT(priv != NULL && memory && size <= 32 * (1 << priv->log2gran));
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/* Get exclusive access to the GAT */
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do
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{
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ret = gran_enter_critical(priv);
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/* The only error Should happen on task cancellation. We must
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* try again in this case to avoid stranding the granule memory.
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*/
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DEBUGASSERT(ret == OK || ret == -ECANCELED);
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}
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while (ret < 0);
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/* Determine the granule number of the first granule in the allocation */
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granno = ((uintptr_t)memory - priv->heapstart) >> priv->log2gran;
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/* Determine the GAT table index and bit number associated with the
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* allocation.
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*/
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gatidx = granno >> 5;
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gatbit = granno & 31;
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/* Determine the number of granules in the allocation */
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granmask = (1 << priv->log2gran) - 1;
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ngranules = (size + granmask) >> priv->log2gran;
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/* Clear bits in the GAT entry or entries */
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avail = 32 - gatbit;
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if (ngranules > avail)
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{
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/* Clear bits in the first GAT entry */
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gatmask = (0xffffffff << gatbit);
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DEBUGASSERT((priv->gat[gatidx] & gatmask) == gatmask);
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priv->gat[gatidx] &= ~gatmask;
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ngranules -= avail;
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/* Clear bits in the second GAT entry */
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gatmask = 0xffffffff >> (32 - ngranules);
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DEBUGASSERT((priv->gat[gatidx + 1] & gatmask) == gatmask);
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priv->gat[gatidx + 1] &= ~gatmask;
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}
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/* Handle the case where where all of the granules came from one entry */
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else
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{
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/* Clear bits in a single GAT entry */
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gatmask = 0xffffffff >> (32 - ngranules);
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gatmask <<= gatbit;
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DEBUGASSERT((priv->gat[gatidx] & gatmask) == gatmask);
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priv->gat[gatidx] &= ~gatmask;
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}
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gran_leave_critical(priv);
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}
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#endif /* CONFIG_GRAN */
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