retained_mem.h

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/*
 * Copyright (c) 2023 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: Apache-2.0
 */

 
#ifndef ZEPHYR_INCLUDE_DRIVERS_RETAINED_MEM_
#define ZEPHYR_INCLUDE_DRIVERS_RETAINED_MEM_
 
#include <stdint.h>
#include <stddef.h>
#include <sys/types.h>
#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <zephyr/types.h>
#include <zephyr/sys/math_extras.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
BUILD_ASSERT(!(sizeof(off_t) > sizeof(size_t)),
             "Size of off_t must be equal or less than size of size_t");



typedef ssize_t (*retained_mem_size_api)(const struct device *dev);

typedef int (*retained_mem_read_api)(const struct device *dev, off_t offset, uint8_t *buffer,
                                     size_t size);

typedef int (*retained_mem_write_api)(const struct device *dev, off_t offset,
                                      const uint8_t *buffer, size_t size);

typedef int (*retained_mem_clear_api)(const struct device *dev);

__subsystem struct retained_mem_driver_api {
        retained_mem_size_api size;
        retained_mem_read_api read;
        retained_mem_write_api write;
        retained_mem_clear_api clear;
};


__syscall ssize_t retained_mem_size(const struct device *dev);
 
static inline ssize_t z_impl_retained_mem_size(const struct device *dev)
{
        return DEVICE_API_GET(retained_mem, dev)->size(dev);
}

__syscall int retained_mem_read(const struct device *dev, off_t offset, uint8_t *buffer,
                                size_t size);
 
static inline int z_impl_retained_mem_read(const struct device *dev, off_t offset,
                                           uint8_t *buffer, size_t size)
{
        const struct retained_mem_driver_api *api = DEVICE_API_GET(retained_mem, dev);
        size_t area_size;
 
        /* Validate user-supplied parameters */
        if (size == 0) {
                return 0;
        }
 
        area_size = api->size(dev);
 
        if (offset < 0 || size > area_size || (area_size - size) < (size_t)offset) {
                return -EINVAL;
        }
 
        return api->read(dev, offset, buffer, size);
}

__syscall int retained_mem_write(const struct device *dev, off_t offset, const uint8_t *buffer,
                                 size_t size);
 
static inline int z_impl_retained_mem_write(const struct device *dev, off_t offset,
                                            const uint8_t *buffer, size_t size)
{
        const struct retained_mem_driver_api *api = DEVICE_API_GET(retained_mem, dev);
        size_t area_size;
 
        /* Validate user-supplied parameters */
        if (size == 0) {
                return 0;
        }
 
        area_size = api->size(dev);
 
        if (offset < 0 || size > area_size || (area_size - size) < (size_t)offset) {
                return -EINVAL;
        }
 
        return api->write(dev, offset, buffer, size);
}

__syscall int retained_mem_clear(const struct device *dev);
 
static inline int z_impl_retained_mem_clear(const struct device *dev)
{
        return DEVICE_API_GET(retained_mem, dev)->clear(dev);
}

 
#ifdef __cplusplus
}
#endif
 
#include <zephyr/syscalls/retained_mem.h>
 
#endif /* ZEPHYR_INCLUDE_DRIVERS_RETAINED_MEM_ */