subsys/fs/zms/zms_priv.h

/* Copyright (c) 2018 Laczen
 * Copyright (c) 2024 BayLibre SAS
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * ZMS: Zephyr Memory Storage
 */

#ifndef __ZMS_PRIV_H_
#define __ZMS_PRIV_H_

/*
 * MASKS AND SHIFT FOR ADDRESSES.
 * An address in zms is an uint64_t where:
 * - high 4 bytes represent the sector number
 * - low 4 bytes represent the offset in a sector
 */
#define ADDR_SECT_MASK   GENMASK64(63, 32)
#define ADDR_SECT_SHIFT  32
#define ADDR_OFFS_MASK   GENMASK64(31, 0)
#define SECTOR_NUM(x)    FIELD_GET(ADDR_SECT_MASK, x)
#define SECTOR_OFFSET(x) FIELD_GET(ADDR_OFFS_MASK, x)

#if defined(CONFIG_ZMS_CUSTOMIZE_BLOCK_SIZE)
#define ZMS_BLOCK_SIZE CONFIG_ZMS_CUSTOM_BLOCK_SIZE
#else
#define ZMS_BLOCK_SIZE 32
#endif

#define ZMS_LOOKUP_CACHE_NO_ADDR GENMASK64(63, 0)

#define ZMS_VERSION_MASK        GENMASK(7, 0)
#define ZMS_GET_VERSION(x)      FIELD_GET(ZMS_VERSION_MASK, x)
#define ZMS_DEFAULT_VERSION     1
#define ZMS_MAGIC_NUMBER        0x42 /* murmur3a hash of "ZMS" (MSB) */
#define ZMS_MAGIC_NUMBER_MASK   GENMASK(15, 8)
#define ZMS_GET_MAGIC_NUMBER(x) FIELD_GET(ZMS_MAGIC_NUMBER_MASK, x)
#define ZMS_ATE_FORMAT_MASK     GENMASK(19, 16)
#define ZMS_GET_ATE_FORMAT(x)   FIELD_GET(ZMS_ATE_FORMAT_MASK, x)
#define ZMS_MIN_ATE_NUM         5

#define ZMS_INVALID_SECTOR_NUM -1

#define ZMS_ATE_FORMAT_ID_32BIT 0
#define ZMS_ATE_FORMAT_ID_64BIT 1

#if !defined(CONFIG_ZMS_ID_64BIT)
#define ZMS_DEFAULT_ATE_FORMAT ZMS_ATE_FORMAT_ID_32BIT
#define ZMS_HEAD_ID            GENMASK(31, 0)
#else
#define ZMS_DEFAULT_ATE_FORMAT ZMS_ATE_FORMAT_ID_64BIT
#define ZMS_HEAD_ID            GENMASK64(63, 0)
#endif /* CONFIG_ZMS_ID_64BIT */

/**
 * @ingroup zms_data_structures
 * ZMS Allocation Table Entry (ATE) structure
 *
 * @note This structure depends on @kconfig{CONFIG_ZMS_ID_64BIT}.
 */
struct zms_ate {
	/** crc8 check of the entry */
	uint8_t crc8;
	/** cycle counter for non erasable devices */
	uint8_t cycle_cnt;
	/** data len within sector */
	uint16_t len;

#if ZMS_DEFAULT_ATE_FORMAT == ZMS_ATE_FORMAT_ID_32BIT
	/** data id */
	uint32_t id;
	union {
		/** data field used to store small sized data */
		uint8_t data[8];
		struct {
			/** data offset within sector */
			uint32_t offset;
			union {
				/**
				 * crc for data: The data CRC is checked only when the whole data
				 * of the element is read.
				 * The data CRC is not checked for a partial read, as it is computed
				 * for the complete set of data.
				 */
				uint32_t data_crc;
				/**
				 * Used to store metadata information such as storage version.
				 */
				uint32_t metadata;
			};
		};
	};

#elif ZMS_DEFAULT_ATE_FORMAT == ZMS_ATE_FORMAT_ID_64BIT
	/** data id */
	uint64_t id;
	union {
		/** data field used to store small sized data */
		uint8_t data[4];
		/** data offset within sector */
		uint32_t offset;
		/** Used to store metadata information such as storage version. */
		uint32_t metadata;
	};
#endif /* ZMS_DEFAULT_ATE_FORMAT */

} __packed;

#define ZMS_DATA_IN_ATE_SIZE SIZEOF_FIELD(struct zms_ate, data)

#endif /* __ZMS_PRIV_H_ */