u-boot/include/env_internal.h

/* SPDX-License-Identifier: GPL-2.0+ */
/*
 * Internal environment header file. This includes direct access to environment
 * information such as its size and offset, direct access to the default
 * environment and embedded environment (if used). It also provides environment
 * drivers with various declarations.
 *
 * It should not be included by board files, drivers and code other than that
 * related to the environment implementation.
 *
 * (C) Copyright 2002
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 */

#ifndef _ENV_INTERNAL_H_
#define _ENV_INTERNAL_H_

#include <linux/kconfig.h>

/**************************************************************************
 *
 * The "environment" is stored as a list of '\0' terminated
 * "name=value" strings. The end of the list is marked by a double
 * '\0'. New entries are always added at the end. Deleting an entry
 * shifts the remaining entries to the front. Replacing an entry is a
 * combination of deleting the old value and adding the new one.
 *
 * The environment is preceded by a 32 bit CRC over the data part.
 *
 *************************************************************************/

#if defined(CONFIG_ENV_IS_IN_FLASH)
# if	defined(CONFIG_ENV_ADDR_REDUND) && \
	((CONFIG_ENV_ADDR >= CONFIG_SYS_MONITOR_BASE) &&		\
	(CONFIG_ENV_ADDR_REDUND + CONFIG_ENV_SIZE) <=		\
	(CONFIG_SYS_MONITOR_BASE + CONFIG_SYS_MONITOR_LEN))
#  define ENV_IS_EMBEDDED
# endif
# if	(CONFIG_ENV_ADDR >= CONFIG_SYS_MONITOR_BASE) &&		\
	(CONFIG_ENV_ADDR + CONFIG_ENV_SIZE) <=			\
	(CONFIG_SYS_MONITOR_BASE + CONFIG_SYS_MONITOR_LEN)
#  define ENV_IS_EMBEDDED
# endif
#endif	/* CONFIG_ENV_IS_IN_FLASH */

#if defined(CONFIG_ENV_IS_IN_NAND)
# if defined(CONFIG_ENV_OFFSET_OOB)
#  ifdef CONFIG_ENV_OFFSET_REDUND
#   error "CONFIG_ENV_OFFSET_REDUND is not supported when CONFIG_ENV_OFFSET_OOB"
#   error "is set"
#  endif
extern unsigned long nand_env_oob_offset;
# endif /* CONFIG_ENV_OFFSET_OOB */
#endif /* CONFIG_ENV_IS_IN_NAND */

#include "compiler.h"

#ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
# define ENV_HEADER_SIZE	(sizeof(uint32_t) + 1)
#else
# define ENV_HEADER_SIZE	(sizeof(uint32_t))
#endif

#define ENV_SIZE (CONFIG_ENV_SIZE - ENV_HEADER_SIZE)

/*
 * If the environment is in RAM, allocate extra space for it in the malloc
 * region.
 */
#if defined(ENV_IS_EMBEDDED)
#define TOTAL_MALLOC_LEN	CONFIG_SYS_MALLOC_LEN
#elif (CONFIG_ENV_ADDR + CONFIG_ENV_SIZE < CONFIG_SYS_MONITOR_BASE) || \
      (CONFIG_ENV_ADDR >= CONFIG_SYS_MONITOR_BASE + CONFIG_SYS_MONITOR_LEN) || \
      defined(CONFIG_ENV_IS_IN_NVRAM)
#define	TOTAL_MALLOC_LEN	(CONFIG_SYS_MALLOC_LEN + CONFIG_ENV_SIZE)
#else
#define	TOTAL_MALLOC_LEN	CONFIG_SYS_MALLOC_LEN
#endif

typedef struct environment_s {
	uint32_t	crc;		/* CRC32 over data bytes	*/
#ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
	unsigned char	flags;		/* active/obsolete flags ENVF_REDUND_ */
#endif
	unsigned char	data[ENV_SIZE]; /* Environment data		*/
} env_t;

#ifdef ENV_IS_EMBEDDED
extern env_t embedded_environment;
#endif /* ENV_IS_EMBEDDED */

#ifdef CONFIG_DEFAULT_ENV_IS_RW
extern char default_environment[];
#else
extern const char default_environment[];
#endif

#ifndef DO_DEPS_ONLY

#include <env_attr.h>
#include <env_callback.h>
#include <env_flags.h>
#include <search.h>

enum env_location {
	ENVL_UNKNOWN,
	ENVL_EEPROM,
	ENVL_EXT4,
	ENVL_FAT,
	ENVL_FLASH,
	ENVL_MMC,
	ENVL_NAND,
	ENVL_NVRAM,
	ENVL_ONENAND,
	ENVL_REMOTE,
	ENVL_SPI_FLASH,
	ENVL_UBI,
	ENVL_NOWHERE,

	ENVL_COUNT,
};

/* value for the various operations we want to perform on the env */
enum env_operation {
	ENVOP_GET_CHAR,	/* we want to call the get_char function */
	ENVOP_INIT,	/* we want to call the init function */
	ENVOP_LOAD,	/* we want to call the load function */
	ENVOP_SAVE,	/* we want to call the save function */
	ENVOP_ERASE,	/* we want to call the erase function */
};

struct env_driver {
	const char *name;
	enum env_location location;

	/**
	 * load() - Load the environment from storage
	 *
	 * This method is required for loading environment
	 *
	 * @return 0 if OK, -ve on error
	 */
	int (*load)(void);

	/**
	 * save() - Save the environment to storage
	 *
	 * This method is required for 'saveenv' to work.
	 *
	 * @return 0 if OK, -ve on error
	 */
	int (*save)(void);

	/**
	 * erase() - Erase the environment on storage
	 *
	 * This method is optional and required for 'eraseenv' to work.
	 *
	 * @return 0 if OK, -ve on error
	 */
	int (*erase)(void);

	/**
	 * init() - Set up the initial pre-relocation environment
	 *
	 * This method is optional.
	 *
	 * @return 0 if OK, -ENOENT if no initial environment could be found,
	 * other -ve on error
	 */
	int (*init)(void);
};

/* Declare a new environment location driver */
#define U_BOOT_ENV_LOCATION(__name)					\
	ll_entry_declare(struct env_driver, __name, env_driver)

/* Declare the name of a location */
#ifdef CONFIG_CMD_SAVEENV
#define ENV_NAME(_name) .name = _name,
#else
#define ENV_NAME(_name)
#endif

#ifdef CONFIG_CMD_SAVEENV
#define env_save_ptr(x) x
#else
#define env_save_ptr(x) NULL
#endif

#define ENV_SAVE_PTR(x) (CONFIG_IS_ENABLED(SAVEENV) ? (x) : NULL)
#define ENV_ERASE_PTR(x) (IS_ENABLED(CONFIG_CMD_ERASEENV) ? (x) : NULL)

extern struct hsearch_data env_htab;

/**
 * env_do_env_set() - Perform the actual setting of an environment variable
 *
 * Due to the number of places we may need to set an environmental variable
 * from we have an exposed internal function that performs the real work and
 * then call this from both the command line function as well as other
 * locations.
 *
 * Return: 0 on success or 1 on failure
 */
int env_do_env_set(int flag, int argc, char *const argv[], int env_flag);

/**
 * env_ext4_get_intf() - Provide the interface for env in EXT4
 *
 * It is a weak function allowing board to overidde the default interface for
 * U-Boot env in EXT4: CONFIG_ENV_EXT4_INTERFACE
 *
 * Return: string of interface, empty if not supported
 */
const char *env_ext4_get_intf(void);

/**
 * env_ext4_get_dev_part() - Provide the device and partition for env in EXT4
 *
 * It is a weak function allowing board to overidde the default device and
 * partition used for U-Boot env in EXT4: CONFIG_ENV_EXT4_DEVICE_AND_PART
 *
 * Return: string of device and partition
 */
const char *env_ext4_get_dev_part(void);

/**
 * arch_env_get_location()- Provide the best location for the U-Boot environment
 *
 * It is a weak function allowing board to overidde the environment location
 * on architecture level. This has lower priority than env_get_location(),
 * which can be defined on board level.
 *
 * @op: operations performed on the environment
 * @prio: priority between the multiple environments, 0 being the
 *        highest priority
 * Return:  an enum env_location value on success, or -ve error code.
 */
enum env_location arch_env_get_location(enum env_operation op, int prio);

/**
 * env_get_location()- Provide the best location for the U-Boot environment
 *
 * It is a weak function allowing board to overidde the environment location
 * on board level. This has higher priority than arch_env_get_location(),
 * which can be defined on architecture level.
 *
 * @op: operations performed on the environment
 * @prio: priority between the multiple environments, 0 being the
 *        highest priority
 * Return:  an enum env_location value on success, or -ve error code.
 */
enum env_location env_get_location(enum env_operation op, int prio);

/**
 * env_fat_get_intf() - Provide the interface for env in FAT
 *
 * It is a weak function allowing board to overidde the default interface for
 * U-Boot env in FAT: CONFIG_ENV_FAT_INTERFACE
 *
 * Return: string of interface, empty if not supported
 */
const char *env_fat_get_intf(void);

/**
 * env_fat_get_dev_part() - Provide the device and partition for env in FAT
 *
 * It is a weak function allowing board to overidde the default device and
 * partition used for U-Boot env in FAT: CONFIG_ENV_FAT_DEVICE_AND_PART
 *
 * Return: string of device and partition
 */
char *env_fat_get_dev_part(void);
#endif /* DO_DEPS_ONLY */

#endif /* _ENV_INTERNAL_H_ */