u-boot/config.mk
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

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Makefile

# SPDX-License-Identifier: GPL-2.0+
#
# (C) Copyright 2000-2013
# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
#########################################################################
# This file is included from ./Makefile and spl/Makefile.
# Clean the state to avoid the same flags added twice.
#
# (Tegra needs different flags for SPL.
# That's the reason why this file must be included from spl/Makefile too.
# If we did not have Tegra SoCs, build system would be much simpler...)
PLATFORM_RELFLAGS :=
PLATFORM_CPPFLAGS :=
KBUILD_LDFLAGS :=
LDFLAGS_FINAL :=
LDFLAGS_STANDALONE :=
OBJCOPYFLAGS :=
# clear VENDOR for tcsh
VENDOR :=
#########################################################################
ARCH := $(CONFIG_SYS_ARCH:"%"=%)
CPU := $(CONFIG_SYS_CPU:"%"=%)
ifdef CONFIG_SPL_BUILD
ifdef CONFIG_ARCH_TEGRA
CPU := arm720t
endif
endif
BOARD := $(CONFIG_SYS_BOARD:"%"=%)
ifneq ($(CONFIG_SYS_VENDOR),)
VENDOR := $(CONFIG_SYS_VENDOR:"%"=%)
endif
ifneq ($(CONFIG_SYS_SOC),)
SOC := $(CONFIG_SYS_SOC:"%"=%)
endif
# Some architecture config.mk files need to know what CPUDIR is set to,
# so calculate CPUDIR before including ARCH/SOC/CPU config.mk files.
# Check if arch/$ARCH/cpu/$CPU exists, otherwise assume arch/$ARCH/cpu contains
# CPU-specific code.
CPUDIR=arch/$(ARCH)/cpu$(if $(CPU),/$(CPU),)
sinclude $(srctree)/arch/$(ARCH)/config.mk # include architecture dependend rules
sinclude $(srctree)/$(CPUDIR)/config.mk # include CPU specific rules
ifdef SOC
sinclude $(srctree)/$(CPUDIR)/$(SOC)/config.mk # include SoC specific rules
endif
ifneq ($(BOARD),)
ifdef VENDOR
BOARDDIR = $(VENDOR)/$(BOARD)
ENVDIR=${vendor}/env
else
BOARDDIR = $(BOARD)
ENVDIR=${board}/env
endif
endif
ifdef BOARD
sinclude $(srctree)/board/$(BOARDDIR)/config.mk # include board specific rules
endif
ifdef FTRACE
PLATFORM_CPPFLAGS += -finstrument-functions -DFTRACE
endif
#########################################################################
RELFLAGS := $(PLATFORM_RELFLAGS)
PLATFORM_CPPFLAGS += $(RELFLAGS)
PLATFORM_CPPFLAGS += -pipe
LDFLAGS_FINAL += -Bstatic
export PLATFORM_CPPFLAGS
export RELFLAGS
export LDFLAGS_FINAL
export LDFLAGS_STANDALONE
export CONFIG_STANDALONE_LOAD_ADDR