426 lines
14 KiB
C
426 lines
14 KiB
C
/****************************************************************************
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* include/nuttx/mm/iob.h
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*
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* Copyright (C) 2014 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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#ifndef _INCLUDE_NUTTX_MM_IOB_H
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#define _INCLUDE_NUTTX_MM_IOB_H
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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 <stdint.h>
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#include <stdbool.h>
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#ifdef CONFIG_MM_IOB
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Configuration ************************************************************/
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/* I/O buffer allocation logic supports a throttle value for read-ahead
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* buffering to prevent the read-ahead logic from consuming all available I/O
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* buffers and blocking the write buffering logic. This throttle logic
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* is only needed if both write buffering and read-ahead buffering are used.
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*
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* The correct way to disable throttling is to set the throttle value to
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* zero.
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*/
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#if !defined(CONFIG_IOB_THROTTLE)
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# define CONFIG_IOB_THROTTLE 0
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#endif
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/* Some I/O buffers should be allocated */
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#if !defined(CONFIG_IOB_NBUFFERS)
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# warning CONFIG_IOB_NBUFFERS not defined
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# define CONFIG_IOB_NBUFFERS 0
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#endif
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#if CONFIG_IOB_NBUFFERS < 1
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# error CONFIG_IOB_NBUFFERS is zero
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#endif
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#if CONFIG_IOB_NBUFFERS <= CONFIG_IOB_THROTTLE
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# error CONFIG_IOB_NBUFFERS <= CONFIG_IOB_THROTTLE
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#endif
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/* IOB helpers */
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#define IOB_DATA(p) (&(p)->io_data[(p)->io_offset])
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#define IOB_FREESPACE(p) (CONFIG_IOB_BUFSIZE - (p)->io_len - (p)->io_offset)
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#if CONFIG_IOB_NCHAINS > 0
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/* Queue helpers */
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# define IOB_QINIT(q) do { (q)->qh_head = 0; (q)->qh_tail = 0; } while (0)
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# define IOB_QEMPTY(q) ((q)->qh_head == NULL)
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#endif
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/****************************************************************************
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* Public Types
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****************************************************************************/
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/* Represents one I/O buffer. A packet is contained by one or more I/O
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* buffers in a chain. The io_pktlen is only valid for the I/O buffer at
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* the head of the chain.
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*/
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struct iob_s
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{
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/* Singly-link list support */
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FAR struct iob_s *io_flink;
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/* Payload */
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#if CONFIG_IOB_BUFSIZE < 256
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uint8_t io_len; /* Length of the data in the entry */
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uint8_t io_offset; /* Data begins at this offset */
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#else
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uint16_t io_len; /* Length of the data in the entry */
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uint16_t io_offset; /* Data begins at this offset */
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#endif
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uint16_t io_pktlen; /* Total length of the packet */
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uint8_t io_data[CONFIG_IOB_BUFSIZE];
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};
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#if CONFIG_IOB_NCHAINS > 0
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/* This container structure supports queuing of I/O buffer chains. This
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* structure is intended only for internal use by the IOB module.
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*/
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struct iob_qentry_s
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{
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/* Singly-link list support */
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FAR struct iob_qentry_s *qe_flink;
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/* Payload -- Head of the I/O buffer chain */
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FAR struct iob_s *qe_head;
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};
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/* The I/O buffer queue head structure */
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struct iob_queue_s
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{
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/* Head of the I/O buffer chain list */
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FAR struct iob_qentry_s *qh_head;
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FAR struct iob_qentry_s *qh_tail;
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};
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#endif /* CONFIG_IOB_NCHAINS > 0 */
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/****************************************************************************
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* Public Data
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****************************************************************************/
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Name: iob_initialize
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*
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* Description:
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* Set up the I/O buffers for normal operations.
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*
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****************************************************************************/
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void iob_initialize(void);
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/****************************************************************************
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* Name: iob_alloc
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*
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* Description:
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* Allocate an I/O buffer by taking the buffer at the head of the free list.
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*
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****************************************************************************/
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FAR struct iob_s *iob_alloc(bool throttled);
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/****************************************************************************
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* Name: iob_tryalloc
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*
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* Description:
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* Try to allocate an I/O buffer by taking the buffer at the head of the
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* free list without waiting for a buffer to become free.
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*
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****************************************************************************/
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FAR struct iob_s *iob_tryalloc(bool throttled);
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/****************************************************************************
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* Name: iob_free
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*
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* Description:
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* Free the I/O buffer at the head of a buffer chain returning it to the
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* free list. The link to the next I/O buffer in the chain is return.
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*
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****************************************************************************/
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FAR struct iob_s *iob_free(FAR struct iob_s *iob);
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/****************************************************************************
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* Name: iob_free_chain
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*
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* Description:
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* Free an entire buffer chain, starting at the beginning of the I/O
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* buffer chain
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*
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****************************************************************************/
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void iob_free_chain(FAR struct iob_s *iob);
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/****************************************************************************
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* Name: iob_add_queue
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*
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* Description:
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* Add one I/O buffer chain to the end of a queue. May fail due to lack
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* of resources.
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*
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****************************************************************************/
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#if CONFIG_IOB_NCHAINS > 0
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int iob_add_queue(FAR struct iob_s *iob, FAR struct iob_queue_s *iobq);
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#endif /* CONFIG_IOB_NCHAINS > 0 */
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/****************************************************************************
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* Name: iob_tryadd_queue
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*
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* Description:
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* Add one I/O buffer chain to the end of a queue without waiting for
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* resources to become free.
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*
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****************************************************************************/
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#if CONFIG_IOB_NCHAINS > 0
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int iob_tryadd_queue(FAR struct iob_s *iob, FAR struct iob_queue_s *iobq);
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#endif /* CONFIG_IOB_NCHAINS > 0 */
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/****************************************************************************
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* Name: iob_remove_queue
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*
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* Description:
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* Remove and return one I/O buffer chain from the head of a queue.
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*
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* Returned Value:
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* Returns a reference to the I/O buffer chain at the head of the queue.
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*
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****************************************************************************/
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#if CONFIG_IOB_NCHAINS > 0
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FAR struct iob_s *iob_remove_queue(FAR struct iob_queue_s *iobq);
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#endif /* CONFIG_IOB_NCHAINS > 0 */
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/****************************************************************************
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* Name: iob_peek_queue
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*
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* Description:
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* Return a reference to the I/O buffer chain at the head of a queue. This
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* is similar to iob_remove_queue except that the I/O buffer chain is in
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* place at the head of the queue. The I/O buffer chain may safely be
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* modified by the caller but must be removed from the queue before it can
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* be freed.
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*
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* Returned Value:
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* Returns a reference to the I/O buffer chain at the head of the queue.
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*
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****************************************************************************/
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#if CONFIG_IOB_NCHAINS > 0
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FAR struct iob_s *iob_peek_queue(FAR struct iob_queue_s *iobq);
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#endif
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/****************************************************************************
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* Name: iob_free_queue
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*
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* Description:
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* Free an entire queue of I/O buffer chains.
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*
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****************************************************************************/
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#if CONFIG_IOB_NCHAINS > 0
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void iob_free_queue(FAR struct iob_queue_s *qhead);
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#endif /* CONFIG_IOB_NCHAINS > 0 */
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/****************************************************************************
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* Name: iob_copyin
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*
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* Description:
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* Copy data 'len' bytes from a user buffer into the I/O buffer chain,
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* starting at 'offset', extending the chain as necessary.
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*
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****************************************************************************/
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int iob_copyin(FAR struct iob_s *iob, FAR const uint8_t *src,
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unsigned int len, unsigned int offset, bool throttled);
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/****************************************************************************
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* Name: iob_trycopyin
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*
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* Description:
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* Copy data 'len' bytes from a user buffer into the I/O buffer chain,
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* starting at 'offset', extending the chain as necessary BUT without
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* waiting if buffers are not available.
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*
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****************************************************************************/
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int iob_trycopyin(FAR struct iob_s *iob, FAR const uint8_t *src,
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unsigned int len, unsigned int offset, bool throttled);
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/****************************************************************************
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* Name: iob_copyout
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*
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* Description:
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* Copy data 'len' bytes of data into the user buffer starting at 'offset'
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* in the I/O buffer, returning that actual number of bytes copied out.
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*
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****************************************************************************/
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int iob_copyout(FAR uint8_t *dest, FAR const struct iob_s *iob,
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unsigned int len, unsigned int offset);
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/****************************************************************************
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* Name: iob_clone
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*
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* Description:
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* Duplicate (and pack) the data in iob1 in iob2. iob2 must be empty.
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*
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****************************************************************************/
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int iob_clone(FAR struct iob_s *iob1, FAR struct iob_s *iob2, bool throttled);
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/****************************************************************************
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* Name: iob_concat
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*
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* Description:
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* Concatenate iob_s chain iob2 to iob1.
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*
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****************************************************************************/
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void iob_concat(FAR struct iob_s *iob1, FAR struct iob_s *iob2);
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/****************************************************************************
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* Name: iob_trimhead
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*
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* Description:
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* Remove bytes from the beginning of an I/O chain. Emptied I/O buffers
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* are freed and, hence, the beginning of the chain may change.
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*
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****************************************************************************/
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FAR struct iob_s *iob_trimhead(FAR struct iob_s *iob, unsigned int trimlen);
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/****************************************************************************
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* Name: iob_trimhead_queue
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*
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* Description:
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* Remove bytes from the beginning of an I/O chain at the head of the
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* queue. Emptied I/O buffers are freed and, hence, the head of the
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* queue may change.
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*
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* This function is just a wrapper around iob_trimhead() that assures that
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* the iob at the head of queue is modified with the trimming operations.
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*
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* Returned Value:
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* The new iob at the head of the queue is returned.
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*
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****************************************************************************/
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#if CONFIG_IOB_NCHAINS > 0
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FAR struct iob_s *iob_trimhead_queue(FAR struct iob_queue_s *qhead,
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unsigned int trimlen);
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#endif
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/****************************************************************************
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* Name: iob_trimtail
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*
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* Description:
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* Remove bytes from the end of an I/O chain. Emptied I/O buffers are
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* freed NULL will be returned in the special case where the entry I/O
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* buffer chain is freed.
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*
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****************************************************************************/
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FAR struct iob_s *iob_trimtail(FAR struct iob_s *iob, unsigned int trimlen);
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/****************************************************************************
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* Name: iob_pack
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*
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* Description:
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* Pack all data in the I/O buffer chain so that the data offset is zero
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* and all but the final buffer in the chain are filled. Any emptied
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* buffers at the end of the chain are freed.
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*
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****************************************************************************/
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FAR struct iob_s *iob_pack(FAR struct iob_s *iob);
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/****************************************************************************
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* Name: iob_contig
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*
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* Description:
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* Ensure that there is 'len' bytes of contiguous space at the beginning
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* of the I/O buffer chain starting at 'iob'.
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*
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****************************************************************************/
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int iob_contig(FAR struct iob_s *iob, unsigned int len);
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/****************************************************************************
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* Name: iob_dump
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*
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* Description:
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* Dump the contents of a I/O buffer chain
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*
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****************************************************************************/
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#ifdef CONFIG_DEBUG_FEATURES
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void iob_dump(FAR const char *msg, FAR struct iob_s *iob, unsigned int len,
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unsigned int offset);
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#else
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# define iob_dump(wrb)
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#endif
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#endif /* CONFIG_MM_IOB */
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#endif /* _INCLUDE_NUTTX_MM_IOB_H */
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