subsys/storage/flash_map/flash_map_layout.c

/*
 * Copyright (c) 2017-2021 Nordic Semiconductor ASA
 * Copyright (c) 2015 Runtime Inc
 * Copyright (c) 2017 Linaro Ltd
 * Copyright (c) 2020 Gerson Fernando Budke <nandojve@gmail.com>
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/types.h>
#include <stddef.h>
#include <sys/types.h>
#include <zephyr/device.h>
#include <zephyr/storage/flash_map.h>
#include <zephyr/drivers/flash.h>
#include <soc.h>
#include <zephyr/init.h>

struct layout_data {
	uint32_t area_idx;
	uint32_t area_off;
	uint32_t area_len;
	void *ret;        /* struct flash_area* or struct flash_sector* */
	uint32_t ret_idx;
	uint32_t ret_len;
	int status;
};

/*
 * Check if a flash_page_foreach() callback should exit early, due to
 * one of the following conditions:
 *
 * - The flash page described by "info" is before the area of interest
 *   described in "data"
 * - The flash page is after the end of the area
 * - There are too many flash pages on the device to fit in the array
 *   held in data->ret. In this case, data->status is set to -ENOMEM.
 *
 * The value to return to flash_page_foreach() is stored in
 * "bail_value" if the callback should exit early.
 */
static bool should_bail(const struct flash_pages_info *info,
						struct layout_data *data,
						bool *bail_value)
{
	if (info->start_offset < data->area_off) {
		*bail_value = true;
		return true;
	} else if (info->start_offset >= data->area_off + data->area_len) {
		*bail_value = false;
		return true;
	} else if (data->ret_idx >= data->ret_len) {
		data->status = -ENOMEM;
		*bail_value = false;
		return true;
	}

	return false;
}

/*
 * Generic page layout discovery routine. This is kept separate to
 * support both the deprecated flash_area_to_sectors() and the current
 * flash_area_get_sectors(). A lot of this can be inlined once
 * flash_area_to_sectors() is removed.
 */
static int flash_area_layout(int idx, uint32_t *cnt, void *ret,
flash_page_cb cb, struct layout_data *cb_data)
{
	const struct device *flash_dev;
	const struct flash_area *fa;
	int rc = flash_area_open(idx, &fa);

	if (rc < 0 || fa == NULL) {
		return -EINVAL;
	}

	cb_data->area_idx = idx;
	cb_data->area_off = fa->fa_off;
	cb_data->area_len = fa->fa_size;

	cb_data->ret = ret;
	cb_data->ret_idx = 0U;
	cb_data->ret_len = *cnt;
	cb_data->status = 0;

	flash_dev = fa->fa_dev;
	flash_area_close(fa);
	if (flash_dev == NULL) {
		return -ENODEV;
	}

	flash_page_foreach(flash_dev, cb, cb_data);

	if (cb_data->status == 0) {
		*cnt = cb_data->ret_idx;
	}

	return cb_data->status;
}

static bool get_sectors_cb(const struct flash_pages_info *info, void *datav)
{
	struct layout_data *data = datav;
	struct flash_sector *ret = data->ret;
	bool bail;

	if (should_bail(info, data, &bail)) {
		return bail;
	}

	ret[data->ret_idx].fs_off = info->start_offset - data->area_off;
	ret[data->ret_idx].fs_size = info->size;
	data->ret_idx++;

	return true;
}

int flash_area_get_sectors(int idx, uint32_t *cnt, struct flash_sector *ret)
{
	struct layout_data data;

	return flash_area_layout(idx, cnt, ret, get_sectors_cb, &data);
}