u-boot/env/embedded.c
Simon Glass 86b9c3e4e4 env: Allow U-Boot scripts to be placed in a .env file
At present U-Boot environment variables, and thus scripts, are defined
by CONFIG_EXTRA_ENV_SETTINGS. It is painful to add large amounts of text
to this file and dealing with quoting and newlines is harder than it
should be. It would be better if we could just type the script into a
text file and have it included by U-Boot.

Add a feature that brings in a .env file associated with the board
config, if present. To use it, create a file in a board/<vendor>
directory, typically called <board>.env and controlled by the
CONFIG_ENV_SOURCE_FILE option.

The environment variables should be of the form "var=value". Values can
extend to multiple lines. See the README under 'Environment Variables:'
for more information and an example.

In many cases environment variables need access to the U-Boot CONFIG
variables to select different options. Enable this so that the environment
scripts can be as useful as the ones currently in the board config files.
This uses the C preprocessor, means that comments can be included in the
environment using /* ... */

Also support += to allow variables to be appended to. This is needed when
using the preprocessor.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Tested-by: Marek Behún <marek.behun@nic.cz>
2021-11-16 14:35:08 -05:00

98 lines
2.5 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2001
* Erik Theisen, Wave 7 Optics, etheisen@mindspring.com.
*/
#include <linux/kconfig.h>
#ifndef __ASSEMBLY__
#define __ASSEMBLY__ /* Dirty trick to get only #defines */
#endif
#define __ASM_STUB_PROCESSOR_H__ /* don't include asm/processor. */
#include <config.h>
#undef __ASSEMBLY__
#include <env_internal.h>
#include <linux/stringify.h>
/* Handle HOSTS that have prepended crap on symbol names, not TARGETS. */
#if defined(__APPLE__)
/* Leading underscore on symbols */
# define SYM_CHAR "_"
#else /* No leading character on symbols */
# define SYM_CHAR
#endif
/*
* Generate embedded environment table
* inside U-Boot image, if needed.
*/
#if defined(ENV_IS_EMBEDDED) || defined(CONFIG_BUILD_ENVCRC)
/*
* Put the environment in the .text section when we are building
* U-Boot proper. The host based program "tools/envcrc" does not need
* a seperate section.
*/
#if defined(USE_HOSTCC) /* Native for 'tools/envcrc' */
# define __UBOOT_ENV_SECTION__(name) /*XXX DO_NOT_DEL_THIS_COMMENT*/
#else /* Environment is embedded in U-Boot's .text section */
/* XXX - This only works with GNU C */
# define __UBOOT_ENV_SECTION__(name) __attribute__ ((section(".text."#name)))
#endif
/*
* Macros to generate global absolutes.
*/
#if defined(__bfin__)
# define GEN_SET_VALUE(name, value) \
asm(".set " GEN_SYMNAME(name) ", " GEN_VALUE(value))
#else
# define GEN_SET_VALUE(name, value) \
asm(GEN_SYMNAME(name) " = " GEN_VALUE(value))
#endif
#define GEN_SYMNAME(str) SYM_CHAR #str
#define GEN_VALUE(str) #str
#define GEN_ABS(name, value) \
asm(".globl " GEN_SYMNAME(name)); \
GEN_SET_VALUE(name, value)
/*
* Check to see if we are building with a
* computed CRC. Otherwise define it as ~0.
*/
#if !defined(ENV_CRC)
# define ENV_CRC (~0)
#endif
#define DEFAULT_ENV_INSTANCE_EMBEDDED
#include <config.h>
#include <env_default.h>
#ifdef CONFIG_ENV_ADDR_REDUND
env_t redundand_environment __UBOOT_ENV_SECTION__(redundand_environment) = {
0, /* CRC Sum: invalid */
0, /* Flags: invalid */
{
"\0"
}
};
#endif /* CONFIG_ENV_ADDR_REDUND */
/*
* These will end up in the .text section
* if the environment strings are embedded
* in the image. When this is used for
* tools/envcrc, they are placed in the
* .data/.sdata section.
*
*/
unsigned long env_size __UBOOT_ENV_SECTION__(env_size) = sizeof(env_t);
/*
* Add in absolutes.
*/
GEN_ABS(env_offset, (CONFIG_ENV_ADDR - CONFIG_SYS_FLASH_BASE));
#endif /* ENV_IS_EMBEDDED */