4fd78583f7
The pci ep framework use bitmap manage free bar Signed-off-by: lipengfei28 <lipengfei28@xiaomi.com>
116 lines
3.1 KiB
C
116 lines
3.1 KiB
C
/****************************************************************************
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* libs/libc/misc/lib_bitmap.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 <assert.h>
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#include <errno.h>
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#include <debug.h>
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#include <string.h>
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#include <nuttx/bits.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: find_next_zero_bit
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*
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* Description:
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* This function is used to find the first cleared bit in a memory region.
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*
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* Invoke to get the bit set in map, implement find_{first,next}_zero_bit.
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*
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* Input Parameters:
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* addr - Map start memory address
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* size - Max size to find bit
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* offset - Offset of start to finding
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*
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* Returned Value:
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* Return index position（0 ~ size-1）if Finded, otherwise return size
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****************************************************************************/
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unsigned long find_next_zero_bit(FAR const unsigned long *addr,
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unsigned long size,
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unsigned long offset)
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{
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FAR const unsigned long *p = addr + BIT_WORD(offset);
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unsigned long result = offset & ~(BITS_PER_LONG - 1);
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unsigned long tmp;
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if (offset >= size)
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{
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return size;
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}
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size -= result;
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offset %= BITS_PER_LONG;
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if (offset)
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{
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tmp = *(p++);
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tmp |= ~0ul >> (BITS_PER_LONG - offset);
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if (size < BITS_PER_LONG)
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{
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goto found_first;
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}
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if (~tmp)
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{
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goto found_middle;
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}
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size -= BITS_PER_LONG;
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result += BITS_PER_LONG;
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}
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while (size & ~(BITS_PER_LONG - 1))
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{
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if (~(tmp = *(p++)))
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{
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goto found_middle;
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}
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result += BITS_PER_LONG;
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size -= BITS_PER_LONG;
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}
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if (!size)
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{
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return result;
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}
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tmp = *p;
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found_first:
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tmp |= ~0ul << size;
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/* Are any bits zero? */
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if (tmp == ~0ul)
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{
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return result + size;
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}
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found_middle:
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return result + ffsl(~tmp) - 1;
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}
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