140 lines
4.4 KiB
C
140 lines
4.4 KiB
C
/****************************************************************************
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* mm/mm_gran/mm_granfree.c
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*
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* Copyright (C) 2012, 2017 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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_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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DEBUGASSERT(priv != NULL && memory && size <= 32 * (1 << priv->log2gran));
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/* Get exclusive access to the GAT */
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gran_enter_critical(priv);
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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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