linux/drivers/staging/media/atomisp/pci/base/circbuf/src/circbuf.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Support for Intel Camera Imaging ISP subsystem.
 * Copyright (c) 2015, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 */

#include "ia_css_circbuf.h"

#include <assert_support.h>

/**********************************************************************
 *
 * Forward declarations.
 *
 **********************************************************************/
/*
 * @brief Read the oldest element from the circular buffer.
 * Read the oldest element WITHOUT checking whether the
 * circular buffer is empty or not. The oldest element is
 * also removed out from the circular buffer.
 *
 * @param cb The pointer to the circular buffer.
 *
 * @return the oldest element.
 */
static inline ia_css_circbuf_elem_t
ia_css_circbuf_read(ia_css_circbuf_t *cb);

/*
 * @brief Shift a chunk of elements in the circular buffer.
 * A chunk of elements (i.e. the ones from the "start" position
 * to the "chunk_src" position) are shifted in the circular buffer,
 * along the direction of new elements coming.
 *
 * @param cb	     The pointer to the circular buffer.
 * @param chunk_src  The position at which the first element in the chunk is.
 * @param chunk_dest The position to which the first element in the chunk would be shift.
 */
static inline void ia_css_circbuf_shift_chunk(ia_css_circbuf_t *cb,
	u32 chunk_src,
	uint32_t chunk_dest);

/*
 * @brief Get the "val" field in the element.
 *
 * @param elem The pointer to the element.
 *
 * @return the "val" field.
 */
static inline uint32_t
ia_css_circbuf_elem_get_val(ia_css_circbuf_elem_t *elem);

/**********************************************************************
 *
 * Non-inline functions.
 *
 **********************************************************************/
/*
 * @brief Create the circular buffer.
 * Refer to "ia_css_circbuf.h" for details.
 */
void
ia_css_circbuf_create(ia_css_circbuf_t *cb,
		      ia_css_circbuf_elem_t *elems,
		      ia_css_circbuf_desc_t *desc)
{ … }

/*
 * @brief Destroy the circular buffer.
 * Refer to "ia_css_circbuf.h" for details.
 */
void ia_css_circbuf_destroy(ia_css_circbuf_t *cb)
{ … }

/*
 * @brief Pop a value out of the circular buffer.
 * Refer to "ia_css_circbuf.h" for details.
 */
uint32_t ia_css_circbuf_pop(ia_css_circbuf_t *cb)
{ … }

/*
 * @brief Extract a value out of the circular buffer.
 * Refer to "ia_css_circbuf.h" for details.
 */
uint32_t ia_css_circbuf_extract(ia_css_circbuf_t *cb, int offset)
{ … }

/*
 * @brief Peek an element from the circular buffer.
 * Refer to "ia_css_circbuf.h" for details.
 */
uint32_t ia_css_circbuf_peek(ia_css_circbuf_t *cb, int offset)
{ … }

/*
 * @brief Get the value of an element from the circular buffer.
 * Refer to "ia_css_circbuf.h" for details.
 */
uint32_t ia_css_circbuf_peek_from_start(ia_css_circbuf_t *cb, int offset)
{ … }

/* @brief increase size of a circular buffer.
 * Use 'CAUTION' before using this function. This was added to
 * support / fix issue with increasing size for tagger only
 * Please refer to "ia_css_circbuf.h" for details.
 */
bool ia_css_circbuf_increase_size(
    ia_css_circbuf_t *cb,
    unsigned int sz_delta,
    ia_css_circbuf_elem_t *elems)
{ … }

/****************************************************************
 *
 * Inline functions.
 *
 ****************************************************************/
/*
 * @brief Get the "val" field in the element.
 * Refer to "Forward declarations" for details.
 */
static inline uint32_t
ia_css_circbuf_elem_get_val(ia_css_circbuf_elem_t *elem)
{ … }

/*
 * @brief Read the oldest element from the circular buffer.
 * Refer to "Forward declarations" for details.
 */
static inline ia_css_circbuf_elem_t
ia_css_circbuf_read(ia_css_circbuf_t *cb)
{ … }

/*
 * @brief Shift a chunk of elements in the circular buffer.
 * Refer to "Forward declarations" for details.
 */
static inline void
ia_css_circbuf_shift_chunk(ia_css_circbuf_t *cb,
			   u32 chunk_src, uint32_t chunk_dest)
{ … }