72 lines
2.1 KiB
C
72 lines
2.1 KiB
C
/*
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* Copyright (C) 2018 Intel Corporation. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#ifndef SHARED_BUF_H
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#define SHARED_BUF_H
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#include <linux/types.h>
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#define SBUF_MAGIC 0x5aa57aa71aa13aa3
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#define SBUF_MAX_SIZE (1ULL << 22)
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#define SBUF_HEAD_SIZE 64
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/* sbuf flags */
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#define OVERRUN_CNT_EN (1ULL << 0) /* whether overrun counting is enabled */
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#define OVERWRITE_EN (1ULL << 1) /* whether overwrite is enabled */
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typedef unsigned char uint8_t;
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typedef unsigned int uint32_t;
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typedef unsigned long uint64_t;
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/**
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* (sbuf) head + buf (store (ele_num - 1) elements at most)
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* buffer empty: tail == head
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* buffer full: (tail + ele_size) % size == head
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*
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* Base of memory for elements
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* |
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* |
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* ---------------------------------------------------------------------------------------
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* | shared_buf_t | raw data (ele_size)| raw date (ele_size) | ... | raw data (ele_size) |
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* ---------------------------------------------------------------------------------------
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* |
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* |
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* shared_buf_t *buf
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*/
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/* Make sure sizeof(shared_buf_t) == SBUF_HEAD_SIZE */
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typedef struct shared_buf {
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uint64_t magic;
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uint32_t ele_num; /* number of elements */
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uint32_t ele_size; /* sizeof of elements */
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uint32_t head; /* offset from base, to read */
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uint32_t tail; /* offset from base, to write */
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uint64_t flags;
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uint32_t overrun_cnt; /* count of overrun */
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uint32_t size; /* ele_num * ele_size */
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uint32_t padding[6];
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} shared_buf_t;
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static inline void sbuf_clear_flags(shared_buf_t *sbuf, uint64_t flags)
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{
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sbuf->flags &= ~flags;
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}
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static inline void sbuf_set_flags(shared_buf_t *sbuf, uint64_t flags)
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{
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sbuf->flags = flags;
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}
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static inline void sbuf_add_flags(shared_buf_t *sbuf, uint64_t flags)
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{
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sbuf->flags |= flags;
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}
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int sbuf_get(shared_buf_t *sbuf, uint8_t *data);
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int sbuf_write(int fd, shared_buf_t *sbuf);
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int sbuf_clear_buffered(shared_buf_t *sbuf);
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#endif /* SHARED_BUF_H */
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