spsc_pbuf.h

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/*
 * Copyright (c) 2022 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: Apache-2.0
 */
 
#ifndef ZEPHYR_INCLUDE_SYS_SPSC_PBUF_H_
#define ZEPHYR_INCLUDE_SYS_SPSC_PBUF_H_
 
#include <zephyr/cache.h>
#include <zephyr/devicetree.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
#define SPSC_PBUF_CACHE BIT(0)
 
#define SPSC_PBUF_UTILIZATION_BITS 24
 
#define SPSC_PBUF_UTILIZATION_OFFSET 8
 
#if CONFIG_DCACHE_LINE_SIZE != 0
#define Z_SPSC_PBUF_LOCAL_DCACHE_LINE CONFIG_DCACHE_LINE_SIZE
#else
#define Z_SPSC_PBUF_LOCAL_DCACHE_LINE DT_PROP_OR(CPU, d_cache_line_size, 0)
#endif
 
#ifndef CONFIG_SPSC_PBUF_REMOTE_DCACHE_LINE
#define CONFIG_SPSC_PBUF_REMOTE_DCACHE_LINE 0
#endif
 
#define Z_SPSC_PBUF_DCACHE_LINE \
        MAX(CONFIG_SPSC_PBUF_REMOTE_DCACHE_LINE, Z_SPSC_PBUF_LOCAL_DCACHE_LINE)
 
#define SPSC_PBUF_MAX_LEN 0xFF00
 
struct spsc_pbuf_common {
        uint32_t len;           /* Length of data[] in bytes. */
        uint32_t flags;         /* Flags. See @ref SPSC_PBUF_FLAGS */
        uint32_t rd_idx;        /* Index of the first valid byte in data[] */
};
 
/* Padding to fill cache line. */
#define Z_SPSC_PBUF_PADDING \
        MAX(0, Z_SPSC_PBUF_DCACHE_LINE - (int)sizeof(struct spsc_pbuf_common))
 
struct spsc_pbuf_ext_cache {
        uint8_t reserved[Z_SPSC_PBUF_PADDING];
        uint32_t wr_idx;        /* Index of the first free byte in data[] */
        uint8_t data[];         /* Buffer data. */
};
 
struct spsc_pbuf_ext_nocache {
        uint32_t wr_idx;        /* Index of the first free byte in data[] */
        uint8_t data[];         /* Buffer data. */
};
 
struct spsc_pbuf {
        struct spsc_pbuf_common common;
        union {
                struct spsc_pbuf_ext_cache cache;
                struct spsc_pbuf_ext_nocache nocache;
        } ext;
};
 
static inline uint32_t spsc_pbuf_capacity(struct spsc_pbuf *pb)
{
        return pb->common.len - sizeof(uint32_t);
}
 
struct spsc_pbuf *spsc_pbuf_init(void *buf, size_t blen, uint32_t flags);
 
int spsc_pbuf_write(struct spsc_pbuf *pb, const char *buf, uint16_t len);
 
int spsc_pbuf_alloc(struct spsc_pbuf *pb, uint16_t len, char **buf);
 
void spsc_pbuf_commit(struct spsc_pbuf *pb, uint16_t len);
 
int spsc_pbuf_read(struct spsc_pbuf *pb, char *buf, uint16_t len);
 
uint16_t spsc_pbuf_claim(struct spsc_pbuf *pb, char **buf);
 
void spsc_pbuf_free(struct spsc_pbuf *pb, uint16_t len);
 
int spsc_pbuf_get_utilization(struct spsc_pbuf *pb);
#ifdef __cplusplus
}
#endif
 
#endif /* ZEPHYR_INCLUDE_SYS_SPSC_PBUF_H_ */