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Merge branch '2021-11-16-env-rework' into next

Browse source 
To quote Simon:

One barrier to completing the 7-year-long Kconfig migration is that
the default environment is implemented using ad-hoc CONFIG options.
At present U-Boot environment variables, and thus scripts, are defined
by CONFIG_EXTRA_ENV_SETTINGS.

It is not really feasible to move the environment to Kconfig as it is
hundreds of lines of text in some cases.

Even considering the current situation, it is painful to add large
amounts of text to the config-header 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.

This is already supported by the CONFIG_USE_DEFAULT_ENV_FILE feature. But
that does not support use of CONFIG options or comments, so is best suited
for use by other build systems wanting to define the U-Boot environment.

Add a feature that brings in a .env file associated with the board
config, if present. To use it, create a file board/<vendor>/<board>.env or
use CONFIG_ENV_SOURCE_FILE to set a filename.

The environment variables should be of the form "var=value". Values can
extend to multiple lines. This series converts the existing environment
documentation to rST and updates it to explain how to use this.
This commit is contained in:
Tom Rini 2021-11-16 20:55:12 -05:00
commit f299171c1d
20 changed files with 850 additions and 378 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
MAINTAINERS
View file

@ -760,6 +760,13 @@ F: test/env/
F: tools/env*
F: tools/mkenvimage.c
ENVIRONMENT AS TEXT
M: Simon Glass <sjg@chromium.org>
R: Wolfgang Denk <wd@denx.de>
S: Maintained
F: doc/usage/environment.rst
F: scripts/env2string.awk
FPGA
M: Michal Simek <michal.simek@xilinx.com>
S: Maintained

66
Makefile
View file

@ -517,6 +517,7 @@ version_h := include/generated/version_autogenerated.h
timestamp_h := include/generated/timestamp_autogenerated.h
defaultenv_h := include/generated/defaultenv_autogenerated.h
dt_h := include/generated/dt.h
env_h := include/generated/environment.h
no-dot-config-targets := clean clobber mrproper distclean \
help %docs check% coccicheck \
@ -1794,6 +1795,69 @@ quiet_cmd_sym ?= SYM $@
u-boot.sym: u-boot FORCE
$(call if_changed,sym)
# Environment processing
# ---------------------------------------------------------------------------
# Directory where we expect the .env file, if it exists
ENV_DIR := $(srctree)/board/$(BOARDDIR)
# Basename of .env file, stripping quotes
ENV_SOURCE_FILE := $(CONFIG_ENV_SOURCE_FILE:"%"=%)
# Filename of .env file
ENV_FILE_CFG := $(ENV_DIR)/$(ENV_SOURCE_FILE).env
# Default filename, if CONFIG_ENV_SOURCE_FILE is empty
ENV_FILE_BOARD := $(ENV_DIR)/$(CONFIG_SYS_BOARD:"%"=%).env
# Select between the CONFIG_ENV_SOURCE_FILE and the default one
ENV_FILE := $(if $(ENV_SOURCE_FILE),$(ENV_FILE_CFG),$(wildcard $(ENV_FILE_BOARD)))
# Run the environment text file through the preprocessor, but only if it is
# non-empty, to save time and possible build errors if something is wonky with
# the board
quiet_cmd_gen_envp = ENVP $@
cmd_gen_envp = \
if [ -s "$(ENV_FILE)" ]; then \
$(CPP) -P $(CFLAGS) -x assembler-with-cpp -D__ASSEMBLY__ \
-D__UBOOT_CONFIG__ \
-I . -I include -I $(srctree)/include \
-include linux/kconfig.h -include include/config.h \
-I$(srctree)/arch/$(ARCH)/include \
$< -o $@; \
else \
echo -n >$@ ; \
fi
include/generated/env.in: include/generated/env.txt FORCE
$(call cmd,gen_envp)
# Regenerate the environment if it changes
# We use 'wildcard' since the file is not required to exist (at present), in
# which case we don't want this dependency, but instead should create an empty
# file
# This rule is useful since it shows the source file for the environment
quiet_cmd_envc = ENVC $@
cmd_envc = \
if [ -f "$<" ]; then \
cat $< > $@; \
elif [ -n "$(ENV_SOURCE_FILE)" ]; then \
echo "Missing file $(ENV_FILE_CFG)"; \
else \
echo -n >$@ ; \
fi
include/generated/env.txt: $(wildcard $(ENV_FILE)) FORCE
$(call cmd,envc)
# Write out the resulting environment, converted to a C string
quiet_cmd_gen_envt = ENVT $@
cmd_gen_envt = \
awk -f $(srctree)/scripts/env2string.awk $< >$@
$(env_h): include/generated/env.in
$(call cmd,gen_envt)
# ---------------------------------------------------------------------------
# The actual objects are generated when descending,
# make sure no implicit rule kicks in
$(sort $(u-boot-init) $(u-boot-main)): $(u-boot-dirs) ;
@ -1849,7 +1913,7 @@ endif
# prepare2 creates a makefile if using a separate output directory
prepare2: prepare3 outputmakefile cfg
prepare1: prepare2 $(version_h) $(timestamp_h) $(dt_h) \
prepare1: prepare2 $(version_h) $(timestamp_h) $(dt_h) $(env_h) \
include/config/auto.conf
ifeq ($(wildcard $(LDSCRIPT)),)
@echo >&2 " Could not find linker script."

328
README
View file

@ -2966,334 +2966,6 @@ TODO.
For now: just type "help <command>".
Environment Variables:
======================
U-Boot supports user configuration using Environment Variables which
can be made persistent by saving to Flash memory.
Environment Variables are set using "setenv", printed using
"printenv", and saved to Flash using "saveenv". Using "setenv"
without a value can be used to delete a variable from the
environment. As long as you don't save the environment you are
working with an in-memory copy. In case the Flash area containing the
environment is erased by accident, a default environment is provided.
Some configuration options can be set using Environment Variables.
List of environment variables (most likely not complete):
baudrate - see CONFIG_BAUDRATE
bootdelay - see CONFIG_BOOTDELAY
bootcmd - see CONFIG_BOOTCOMMAND
bootargs - Boot arguments when booting an RTOS image
bootfile - Name of the image to load with TFTP
bootm_low - Memory range available for image processing in the bootm
command can be restricted. This variable is given as
a hexadecimal number and defines lowest address allowed
for use by the bootm command. See also "bootm_size"
environment variable. Address defined by "bootm_low" is
also the base of the initial memory mapping for the Linux
kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
bootm_mapsize.
bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
This variable is given as a hexadecimal number and it
defines the size of the memory region starting at base
address bootm_low that is accessible by the Linux kernel
during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
as the default value if it is defined, and bootm_size is
used otherwise.
bootm_size - Memory range available for image processing in the bootm
command can be restricted. This variable is given as
a hexadecimal number and defines the size of the region
allowed for use by the bootm command. See also "bootm_low"
environment variable.
bootstopkeysha256, bootdelaykey, bootstopkey - See README.autoboot
updatefile - Location of the software update file on a TFTP server, used
by the automatic software update feature. Please refer to
documentation in doc/README.update for more details.
autoload - if set to "no" (any string beginning with 'n'),
"bootp" will just load perform a lookup of the
configuration from the BOOTP server, but not try to
load any image using TFTP
autostart - if set to "yes", an image loaded using the "bootp",
"rarpboot", "tftpboot" or "diskboot" commands will
be automatically started (by internally calling
"bootm")
If set to "no", a standalone image passed to the
"bootm" command will be copied to the load address
(and eventually uncompressed), but NOT be started.
This can be used to load and uncompress arbitrary
data.
fdt_high - if set this restricts the maximum address that the
flattened device tree will be copied into upon boot.
For example, if you have a system with 1 GB memory
at physical address 0x10000000, while Linux kernel
only recognizes the first 704 MB as low memory, you
may need to set fdt_high as 0x3C000000 to have the
device tree blob be copied to the maximum address
of the 704 MB low memory, so that Linux kernel can
access it during the boot procedure.
If this is set to the special value 0xFFFFFFFF then
the fdt will not be copied at all on boot. For this
to work it must reside in writable memory, have
sufficient padding on the end of it for u-boot to
add the information it needs into it, and the memory
must be accessible by the kernel.
fdtcontroladdr- if set this is the address of the control flattened
device tree used by U-Boot when CONFIG_OF_CONTROL is
defined.
i2cfast - (PPC405GP|PPC405EP only)
if set to 'y' configures Linux I2C driver for fast
mode (400kHZ). This environment variable is used in
initialization code. So, for changes to be effective
it must be saved and board must be reset.
initrd_high - restrict positioning of initrd images:
If this variable is not set, initrd images will be
copied to the highest possible address in RAM; this
is usually what you want since it allows for
maximum initrd size. If for some reason you want to
make sure that the initrd image is loaded below the
CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
variable to a value of "no" or "off" or "0".
Alternatively, you can set it to a maximum upper
address to use (U-Boot will still check that it
does not overwrite the U-Boot stack and data).
For instance, when you have a system with 16 MB
RAM, and want to reserve 4 MB from use by Linux,
you can do this by adding "mem=12M" to the value of
the "bootargs" variable. However, now you must make
sure that the initrd image is placed in the first
12 MB as well - this can be done with
setenv initrd_high 00c00000
If you set initrd_high to 0xFFFFFFFF, this is an
indication to U-Boot that all addresses are legal
for the Linux kernel, including addresses in flash
memory. In this case U-Boot will NOT COPY the
ramdisk at all. This may be useful to reduce the
boot time on your system, but requires that this
feature is supported by your Linux kernel.
ipaddr - IP address; needed for tftpboot command
loadaddr - Default load address for commands like "bootp",
"rarpboot", "tftpboot", "loadb" or "diskboot"
loads_echo - see CONFIG_LOADS_ECHO
serverip - TFTP server IP address; needed for tftpboot command
bootretry - see CONFIG_BOOT_RETRY_TIME
bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
ethprime - controls which interface is used first.
ethact - controls which interface is currently active.
For example you can do the following
=> setenv ethact FEC
=> ping 192.168.0.1 # traffic sent on FEC
=> setenv ethact SCC
=> ping 10.0.0.1 # traffic sent on SCC
ethrotate - When set to "no" U-Boot does not go through all
available network interfaces.
It just stays at the currently selected interface.
netretry - When set to "no" each network operation will
either succeed or fail without retrying.
When set to "once" the network operation will
fail when all the available network interfaces
are tried once without success.
Useful on scripts which control the retry operation
themselves.
npe_ucode - set load address for the NPE microcode
silent_linux - If set then Linux will be told to boot silently, by
changing the console to be empty. If "yes" it will be
made silent. If "no" it will not be made silent. If
unset, then it will be made silent if the U-Boot console
is silent.
tftpsrcp - If this is set, the value is used for TFTP's
UDP source port.
tftpdstp - If this is set, the value is used for TFTP's UDP
destination port instead of the Well Know Port 69.
tftpblocksize - Block size to use for TFTP transfers; if not set,
we use the TFTP server's default block size
tftptimeout - Retransmission timeout for TFTP packets (in milli-
seconds, minimum value is 1000 = 1 second). Defines
when a packet is considered to be lost so it has to
be retransmitted. The default is 5000 = 5 seconds.
Lowering this value may make downloads succeed
faster in networks with high packet loss rates or
with unreliable TFTP servers.
tftptimeoutcountmax - maximum count of TFTP timeouts (no
unit, minimum value = 0). Defines how many timeouts
can happen during a single file transfer before that
transfer is aborted. The default is 10, and 0 means
'no timeouts allowed'. Increasing this value may help
downloads succeed with high packet loss rates, or with
unreliable TFTP servers or client hardware.
tftpwindowsize - if this is set, the value is used for TFTP's
window size as described by RFC 7440.
This means the count of blocks we can receive before
sending ack to server.
vlan - When set to a value < 4095 the traffic over
Ethernet is encapsulated/received over 802.1q
VLAN tagged frames.
bootpretryperiod - Period during which BOOTP/DHCP sends retries.
Unsigned value, in milliseconds. If not set, the period will
be either the default (28000), or a value based on
CONFIG_NET_RETRY_COUNT, if defined. This value has
precedence over the valu based on CONFIG_NET_RETRY_COUNT.
memmatches - Number of matches found by the last 'ms' command, in hex
memaddr - Address of the last match found by the 'ms' command, in hex,
or 0 if none
mempos - Index position of the last match found by the 'ms' command,
in units of the size (.b, .w, .l) of the search
zbootbase - (x86 only) Base address of the bzImage 'setup' block
zbootaddr - (x86 only) Address of the loaded bzImage, typically
BZIMAGE_LOAD_ADDR which is 0x100000
The following image location variables contain the location of images
used in booting. The "Image" column gives the role of the image and is
not an environment variable name. The other columns are environment
variable names. "File Name" gives the name of the file on a TFTP
server, "RAM Address" gives the location in RAM the image will be
loaded to, and "Flash Location" gives the image's address in NOR
flash or offset in NAND flash.
*Note* - these variables don't have to be defined for all boards, some
boards currently use other variables for these purposes, and some
boards use these variables for other purposes.
Image File Name RAM Address Flash Location
----- --------- ----------- --------------
u-boot u-boot u-boot_addr_r u-boot_addr
Linux kernel bootfile kernel_addr_r kernel_addr
device tree blob fdtfile fdt_addr_r fdt_addr
ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
The following environment variables may be used and automatically
updated by the network boot commands ("bootp" and "rarpboot"),
depending the information provided by your boot server:
bootfile - see above
dnsip - IP address of your Domain Name Server
dnsip2 - IP address of your secondary Domain Name Server
gatewayip - IP address of the Gateway (Router) to use
hostname - Target hostname
ipaddr - see above
netmask - Subnet Mask
rootpath - Pathname of the root filesystem on the NFS server
serverip - see above
There are two special Environment Variables:
serial# - contains hardware identification information such
as type string and/or serial number
ethaddr - Ethernet address
These variables can be set only once (usually during manufacturing of
the board). U-Boot refuses to delete or overwrite these variables
once they have been set once.
Further special Environment Variables:
ver - Contains the U-Boot version string as printed
with the "version" command. This variable is
readonly (see CONFIG_VERSION_VARIABLE).
Please note that changes to some configuration parameters may take
only effect after the next boot (yes, that's just like Windoze :-).
Callback functions for environment variables:
---------------------------------------------
For some environment variables, the behavior of u-boot needs to change
when their values are changed. This functionality allows functions to
be associated with arbitrary variables. On creation, overwrite, or
deletion, the callback will provide the opportunity for some side
effect to happen or for the change to be rejected.
The callbacks are named and associated with a function using the
U_BOOT_ENV_CALLBACK macro in your board or driver code.
These callbacks are associated with variables in one of two ways. The
static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
in the board configuration to a string that defines a list of
associations. The list must be in the following format:
entry = variable_name[:callback_name]
list = entry[,list]
If the callback name is not specified, then the callback is deleted.
Spaces are also allowed anywhere in the list.
Callbacks can also be associated by defining the ".callbacks" variable
with the same list format above. Any association in ".callbacks" will
override any association in the static list. You can define
CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
".callbacks" environment variable in the default or embedded environment.
If CONFIG_REGEX is defined, the variable_name above is evaluated as a
regular expression. This allows multiple variables to be connected to
the same callback without explicitly listing them all out.
The signature of the callback functions is:
int callback(const char *name, const char *value, enum env_op op, int flags)
* name - changed environment variable
* value - new value of the environment variable
* op - operation (create, overwrite, or delete)
* flags - attributes of the environment variable change, see flags H_* in
include/search.h
The return value is 0 if the variable change is accepted and 1 otherwise.
Note for Redundant Ethernet Interfaces:
=======================================

25
board/sandbox/sandbox.env Normal file
View file

@ -0,0 +1,25 @@
stdin=serial
#ifdef CONFIG_SANDBOX_SDL
stdin+=,cros-ec-keyb,usbkbd
#endif
stdout=serial,vidconsole
stderr=serial,vidconsole
ethaddr=02:00:11:22:33:44
eth2addr=02:00:11:22:33:48
eth3addr=02:00:11:22:33:45
eth4addr=02:00:11:22:33:48
eth5addr=02:00:11:22:33:46
eth6addr=02:00:11:22:33:47
ipaddr=192.0.2.1
/*
* These are used for distro boot which is not supported. But once bootmethod
* is provided these will be used again.
*/
bootm_size=0x10000000
kernel_addr_r=0x1000000
fdt_addr_r=0xc00000
ramdisk_addr_r=0x2000000
scriptaddr=0x1000
pxefile_addr_r=0x2000

5
boot/bootm_os.c
View file

@ -26,12 +26,9 @@ DECLARE_GLOBAL_DATA_PTR;
static int do_bootm_standalone(int flag, int argc, char *const argv[],
bootm_headers_t *images)
{
char *s;
int (*appl)(int, char *const[]);
/* Don't start if "autostart" is set to "no" */
s = env_get("autostart");
if ((s != NULL) && !strcmp(s, "no")) {
if (!env_get_autostart()) {
env_set_hex("filesize", images->os.image_len);
return 0;
}

4
cmd/bootm.c
View file

@ -140,9 +140,7 @@ int do_bootm(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
int bootm_maybe_autostart(struct cmd_tbl *cmdtp, const char *cmd)
{
const char *ep = env_get("autostart");
if (ep && !strcmp(ep, "yes")) {
if (env_get_autostart()) {
char *local_args[2];
local_args[0] = (char *)cmd;
local_args[1] = NULL;

3
cmd/elf.c
View file

@ -41,7 +41,6 @@ int do_bootelf(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
unsigned long addr; /* Address of the ELF image */
unsigned long rc; /* Return value from user code */
char *sload = NULL;
const char *ep = env_get("autostart");
int rcode = 0;
/* Consume 'bootelf' */
@ -69,7 +68,7 @@ int do_bootelf(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
else
addr = load_elf_image_shdr(addr);
if (ep && !strcmp(ep, "no"))
if (!env_get_autostart())
return rcode;
printf("## Starting application at 0x%08lx ...\n", addr);

2
config.mk
View file

@ -50,8 +50,10 @@ endif
ifneq ($(BOARD),)
ifdef VENDOR
BOARDDIR = $(VENDOR)/$(BOARD)
ENVDIR=${vendor}/env
else
BOARDDIR = $(BOARD)
ENVDIR=${board}/env
endif
endif
ifdef BOARD

51
doc/develop/environment.rst Normal file
View file

@ -0,0 +1,51 @@
.. SPDX-License-Identifier: GPL-2.0+
Environment implementation
==========================
See :doc:`../usage/environment` for usage information.
Callback functions for environment variables
--------------------------------------------
For some environment variables, the behavior of u-boot needs to change
when their values are changed. This functionality allows functions to
be associated with arbitrary variables. On creation, overwrite, or
deletion, the callback will provide the opportunity for some side
effect to happen or for the change to be rejected.
The callbacks are named and associated with a function using the
U_BOOT_ENV_CALLBACK macro in your board or driver code.
These callbacks are associated with variables in one of two ways. The
static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
in the board configuration to a string that defines a list of
associations. The list must be in the following format::
entry = variable_name[:callback_name]
list = entry[,list]
If the callback name is not specified, then the callback is deleted.
Spaces are also allowed anywhere in the list.
Callbacks can also be associated by defining the ".callbacks" variable
with the same list format above. Any association in ".callbacks" will
override any association in the static list. You can define
CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
".callbacks" environment variable in the default or embedded environment.
If CONFIG_REGEX is defined, the variable_name above is evaluated as a
regular expression. This allows multiple variables to be connected to
the same callback without explicitly listing them all out.
The signature of the callback functions is::
int callback(const char *name, const char *value, enum env_op op, int flags)
* name - changed environment variable
* value - new value of the environment variable
* op - operation (create, overwrite, or delete)
* flags - attributes of the environment variable change, see flags H_* in
include/search.h
The return value is 0 if the variable change is accepted and 1 otherwise.

1
doc/develop/index.rst
View file

@ -16,6 +16,7 @@ Implementation
devicetree/index
distro
driver-model/index
environment
global_data
logging
makefiles

465
doc/usage/environment.rst Normal file
View file

@ -0,0 +1,465 @@
.. SPDX-License-Identifier: GPL-2.0+
Environment Variables
=====================
U-Boot supports user configuration using environment variables which
can be made persistent by saving to persistent storage, for example flash
memory.
Environment variables are set using "env set" (alias "setenv"), printed using
"env print" (alias "printenv"), and saved to persistent storage using
"env save" (alias "saveenv"). Using "env set"
without a value can be used to delete a variable from the
environment. As long as you don't save the environment, you are
working with an in-memory copy. In case the Flash area containing the
environment is erased by accident, a default environment is provided.
Some configuration is controlled by Environment Variables, so that setting the
variable can adjust the behaviour of U-Boot (e.g. autoboot delay, autoloading
from tftp).
Text-based Environment
----------------------
The default environment for a board is created using a `.env` environment file
using a simple text format. The base filename for this is defined by
`CONFIG_ENV_SOURCE_FILE`, or `CONFIG_SYS_BOARD` if that is empty.
The file must be in the board directory and have a .env extension, so
assuming that there is a board vendor, the resulting filename is therefore::
board/<vendor>/<board>/<CONFIG_ENV_SOURCE_FILE>.env
or::
board/<vendor>/<board>/<CONFIG_SYS_BOARD>.env
This is a plain text file where you can type your environment variables in
the form `var=value`. Blank lines and multi-line variables are supported.
The conversion script looks for a line that starts in column 1 with a string
and has an equals sign immediately afterwards. Spaces before the = are not
permitted. It is a good idea to indent your scripts so that only the 'var='
appears at the start of a line.
To add additional text to a variable you can use `var+=value`. This text is
merged into the variable during the make process and made available as a
single value to U-Boot. Variables can contain `+` characters but in the unlikely
event that you want to have a variable name ending in plus, put a backslash
before the `+` so that the script knows you are not adding to an existing
variable but assigning to a new one::
maximum\+=value
This file can include C-style comments. Blank lines and multi-line
variables are supported, and you can use normal C preprocessor directives
and CONFIG defines from your board config also.
For example, for snapper9260 you would create a text file called
`board/bluewater/snapper9260.env` containing the environment text.
Example::
stdout=serial
#ifdef CONFIG_LCD
stdout+=,lcd
#endif
bootcmd=
/* U-Boot script for booting */
if [ -z ${tftpserverip} ]; then
echo "Use 'setenv tftpserverip a.b.c.d' to set IP address."
fi
usb start; setenv autoload n; bootp;
tftpboot ${tftpserverip}:
bootm
failed=
/* Print a message when boot fails */
echo CONFIG_SYS_BOARD boot failed - please check your image
echo Load address is CONFIG_SYS_LOAD_ADDR
If CONFIG_ENV_SOURCE_FILE is empty and the default filename is not present, then
the old-style C environment is used instead. See below.
Old-style C environment
-----------------------
Traditionally, the default environment is created in `include/env_default.h`,
and can be augmented by various `CONFIG` defines. See that file for details. In
particular you can define `CONFIG_EXTRA_ENV_SETTINGS` in your board file
to add environment variables.
Board maintainers are encouraged to migrate to the text-based environment as it
is easier to maintain. The distro-board script still requires the old-style
environment but work is underway to address this.
List of environment variables
-----------------------------
Some device configuration options can be set using environment variables. In
many cases the value in the default environment comes from a CONFIG option - see
`include/env_default.h`) for this.
This is most-likely not complete:
baudrate
Used to set the baudrate of the UART - it defaults to CONFIG_BAUDRATE (which
defaults to 115200).
bootdelay
Delay before automatically running bootcmd. During this time the user
can choose to enter the shell (or the boot menu if
CONFIG_AUTOBOOT_MENU_SHOW=y):
- 0 to autoboot with no delay, but you can stop it by key input.
- -1 to disable autoboot.
- -2 to autoboot with no delay and not check for abort
The default value is defined by CONFIG_BOOTDELAY.
The value of 'bootdelay' is overridden by the /config/bootdelay value in
the device-tree if CONFIG_OF_CONTROL=y.
Does it really make sense that the devicetree overrides the user setting?
bootcmd
The command that is run if the user does not enter the shell during the
boot delay.
bootargs
Command line arguments passed when booting an operating system or binary
image
bootfile
Name of the image to load with TFTP
bootm_low
Memory range available for image processing in the bootm
command can be restricted. This variable is given as
a hexadecimal number and defines lowest address allowed
for use by the bootm command. See also "bootm_size"
environment variable. Address defined by "bootm_low" is
also the base of the initial memory mapping for the Linux
kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
bootm_mapsize.
bootm_mapsize
Size of the initial memory mapping for the Linux kernel.
This variable is given as a hexadecimal number and it
defines the size of the memory region starting at base
address bootm_low that is accessible by the Linux kernel
during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
as the default value if it is defined, and bootm_size is
used otherwise.
bootm_size
Memory range available for image processing in the bootm
command can be restricted. This variable is given as
a hexadecimal number and defines the size of the region
allowed for use by the bootm command. See also "bootm_low"
environment variable.
bootstopkeysha256, bootdelaykey, bootstopkey
See README.autoboot
updatefile
Location of the software update file on a TFTP server, used
by the automatic software update feature. Please refer to
documentation in doc/README.update for more details.
autoload
if set to "no" (any string beginning with 'n'),
"bootp" and "dhcp" will just load perform a lookup of the
configuration from the BOOTP server, but not try to
load any image using TFTP or DHCP.
autostart
if set to "yes", an image loaded using the "bootp", "dhcp",
"rarpboot", "tftpboot" or "diskboot" commands will
be automatically started (by internally calling
"bootm")
If unset, or set to "1"/"yes"/"true" (case insensitive, just the first
character is enough), a standalone image
passed to the "bootm" command will be copied to the load address
(and eventually uncompressed), but NOT be started.
This can be used to load and uncompress arbitrary
data.
fdt_high
if set this restricts the maximum address that the
flattened device tree will be copied into upon boot.
For example, if you have a system with 1 GB memory
at physical address 0x10000000, while Linux kernel
only recognizes the first 704 MB as low memory, you
may need to set fdt_high as 0x3C000000 to have the
device tree blob be copied to the maximum address
of the 704 MB low memory, so that Linux kernel can
access it during the boot procedure.
If this is set to the special value 0xffffffff (32-bit machines) or
0xffffffffffffffff (64-bit machines) then
the fdt will not be copied at all on boot. For this
to work it must reside in writable memory, have
sufficient padding on the end of it for u-boot to
add the information it needs into it, and the memory
must be accessible by the kernel.
fdtcontroladdr
if set this is the address of the control flattened
device tree used by U-Boot when CONFIG_OF_CONTROL is
defined.
initrd_high
restrict positioning of initrd images:
If this variable is not set, initrd images will be
copied to the highest possible address in RAM; this
is usually what you want since it allows for
maximum initrd size. If for some reason you want to
make sure that the initrd image is loaded below the
CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
variable to a value of "no" or "off" or "0".
Alternatively, you can set it to a maximum upper
address to use (U-Boot will still check that it
does not overwrite the U-Boot stack and data).
For instance, when you have a system with 16 MB
RAM, and want to reserve 4 MB from use by Linux,
you can do this by adding "mem=12M" to the value of
the "bootargs" variable. However, now you must make
sure that the initrd image is placed in the first
12 MB as well - this can be done with::
setenv initrd_high 00c00000
If you set initrd_high to 0xffffffff (32-bit machines) or
0xffffffffffffffff (64-bit machines), this is an
indication to U-Boot that all addresses are legal
for the Linux kernel, including addresses in flash
memory. In this case U-Boot will NOT COPY the
ramdisk at all. This may be useful to reduce the
boot time on your system, but requires that this
feature is supported by your Linux kernel.
ipaddr
IP address; needed for tftpboot command
loadaddr
Default load address for commands like "bootp",
"rarpboot", "tftpboot", "loadb" or "diskboot"
loads_echo
see CONFIG_LOADS_ECHO
serverip
TFTP server IP address; needed for tftpboot command
bootretry
see CONFIG_BOOT_RETRY_TIME
bootdelaykey
see CONFIG_AUTOBOOT_DELAY_STR
bootstopkey
see CONFIG_AUTOBOOT_STOP_STR
ethprime
controls which network interface is used first.
ethact
controls which interface is currently active.
For example you can do the following::
=> setenv ethact FEC
=> ping 192.168.0.1 # traffic sent on FEC
=> setenv ethact SCC
=> ping 10.0.0.1 # traffic sent on SCC
ethrotate
When set to "no" U-Boot does not go through all
available network interfaces.
It just stays at the currently selected interface. When unset or set to
anything other than "no", U-Boot does go through all
available network interfaces.
netretry
When set to "no" each network operation will
either succeed or fail without retrying.
When set to "once" the network operation will
fail when all the available network interfaces
are tried once without success.
Useful on scripts which control the retry operation
themselves.
silent_linux
If set then Linux will be told to boot silently, by
adding 'console=' to its command line. If "yes" it will be
made silent. If "no" it will not be made silent. If
unset, then it will be made silent if the U-Boot console
is silent.
tftpsrcp
If this is set, the value is used for TFTP's
UDP source port.
tftpdstp
If this is set, the value is used for TFTP's UDP
destination port instead of the default port 69.
tftpblocksize
Block size to use for TFTP transfers; if not set,
we use the TFTP server's default block size
tftptimeout
Retransmission timeout for TFTP packets (in milli-
seconds, minimum value is 1000 = 1 second). Defines
when a packet is considered to be lost so it has to
be retransmitted. The default is 5000 = 5 seconds.
Lowering this value may make downloads succeed
faster in networks with high packet loss rates or
with unreliable TFTP servers.
tftptimeoutcountmax
maximum count of TFTP timeouts (no
unit, minimum value = 0). Defines how many timeouts
can happen during a single file transfer before that
transfer is aborted. The default is 10, and 0 means
'no timeouts allowed'. Increasing this value may help
downloads succeed with high packet loss rates, or with
unreliable TFTP servers or client hardware.
tftpwindowsize
if this is set, the value is used for TFTP's
window size as described by RFC 7440.
This means the count of blocks we can receive before
sending ack to server.
vlan
When set to a value < 4095 the traffic over
Ethernet is encapsulated/received over 802.1q
VLAN tagged frames.
Note: This appears not to be used in U-Boot. See `README.VLAN`.
bootpretryperiod
Period during which BOOTP/DHCP sends retries.
Unsigned value, in milliseconds. If not set, the period will
be either the default (28000), or a value based on
CONFIG_NET_RETRY_COUNT, if defined. This value has
precedence over the valu based on CONFIG_NET_RETRY_COUNT.
memmatches
Number of matches found by the last 'ms' command, in hex
memaddr
Address of the last match found by the 'ms' command, in hex,
or 0 if none
mempos
Index position of the last match found by the 'ms' command,
in units of the size (.b, .w, .l) of the search
zbootbase
(x86 only) Base address of the bzImage 'setup' block
zbootaddr
(x86 only) Address of the loaded bzImage, typically
BZIMAGE_LOAD_ADDR which is 0x100000
Image locations
---------------
The following image location variables contain the location of images
used in booting. The "Image" column gives the role of the image and is
not an environment variable name. The other columns are environment
variable names. "File Name" gives the name of the file on a TFTP
server, "RAM Address" gives the location in RAM the image will be
loaded to, and "Flash Location" gives the image's address in NOR
flash or offset in NAND flash.
*Note* - these variables don't have to be defined for all boards, some
boards currently use other variables for these purposes, and some
boards use these variables for other purposes.
Also note that most of these variables are just a commonly used set of variable
names, used in some other variable definitions, but are not hard-coded anywhere
in U-Boot code.
================= ============== ================ ==============
Image File Name RAM Address Flash Location
================= ============== ================ ==============
u-boot u-boot u-boot_addr_r u-boot_addr
Linux kernel bootfile kernel_addr_r kernel_addr
device tree blob fdtfile fdt_addr_r fdt_addr
ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
================= ============== ================ ==============
Automatically updated variables
-------------------------------
The following environment variables may be used and automatically
updated by the network boot commands ("bootp" and "rarpboot"),
depending the information provided by your boot server:
========= ===================================================
Variable Notes
========= ===================================================
bootfile see above
dnsip IP address of your Domain Name Server
dnsip2 IP address of your secondary Domain Name Server
gatewayip IP address of the Gateway (Router) to use
hostname Target hostname
ipaddr See above
netmask Subnet Mask
rootpath Pathname of the root filesystem on the NFS server
serverip see above
========= ===================================================
Special environment variables
-----------------------------
There are two special Environment Variables:
serial#
contains hardware identification information such as type string and/or
serial number
ethaddr
Ethernet address. If CONFIG_REGEX=y, also eth*addr (where * is an integer).
These variables can be set only once (usually during manufacturing of
the board). U-Boot refuses to delete or overwrite these variables
once they have been set, unless CONFIG_ENV_OVERWRITE is enabled in the board
configuration.
Also:
ver
Contains the U-Boot version string as printed
with the "version" command. This variable is
readonly (see CONFIG_VERSION_VARIABLE).
Please note that changes to some configuration parameters may take
only effect after the next boot (yes, that's just like Windows).
External environment file
-------------------------
The `CONFIG_USE_DEFAULT_ENV_FILE` option provides a way to bypass the
environment generation in U-Boot. If enabled, then `CONFIG_DEFAULT_ENV_FILE`
provides the name of a file which is converted into the environment,
completely bypassing the standard environment variables in `env_default.h`.
The format is the same as accepted by the mkenvimage tool, with lines containing
key=value pairs. Blank lines and lines beginning with # are ignored.
Future work may unify this feature with the text-based environment, perhaps
moving the contents of `env_default.h` to a text file.
Implementation
--------------
See :doc:`../develop/environment` for internal development details.

2
doc/usage/index.rst
View file

@ -5,11 +5,13 @@ Use U-Boot
:maxdepth: 1
dfu
environment
fdt_overlays
fit
netconsole
partitions
cmdline
environment
Shell commands
--------------

18
env/Kconfig vendored
View file

@ -3,6 +3,24 @@ menu "Environment"
config ENV_SUPPORT
def_bool y
config ENV_SOURCE_FILE
string "Environment file to use"
default ""
help
This sets the basename to use to generate the default environment.
This a text file as described in doc/usage/environment.rst
The file must be in the board directory and have a .env extension, so
the resulting filename is typically
board/<vendor>/<board>/<CONFIG_ENV_SOURCE_FILE>.env
If the file is not present, an error is produced.
If this CONFIG is empty, U-Boot uses CONFIG SYS_BOARD as a default, if
the file board/<vendor>/<board>/<SYS_BOARD>.env exists. Otherwise the
environment is assumed to come from the ad-hoc
CONFIG_EXTRA_ENV_SETTINGS #define
config SAVEENV
def_bool y if CMD_SAVEENV

5
env/common.c vendored
View file

@ -235,6 +235,11 @@ int env_get_yesno(const char *var)
1 : 0;
}
bool env_get_autostart(void)
{
return env_get_yesno("autostart") == 1;
}
/*
* Look up the variable from the default environment
*/

1
env/embedded.c vendored
View file

@ -66,6 +66,7 @@
#endif
#define DEFAULT_ENV_INSTANCE_EMBEDDED
#include <config.h>
#include <env_default.h>
#ifdef CONFIG_ENV_ADDR_REDUND

40
include/configs/sandbox.h
View file

@ -39,16 +39,6 @@
#define CONFIG_SYS_BAUDRATE_TABLE {4800, 9600, 19200, 38400, 57600,\
115200}
#define BOOT_TARGET_DEVICES(func) \
func(HOST, host, 1) \
func(HOST, host, 0)
#ifdef __ASSEMBLY__
#define BOOTENV
#else
#include <config_distro_bootcmd.h>
#endif
#define CONFIG_KEEP_SERVERADDR
#define CONFIG_UDP_CHECKSUM
#define CONFIG_TIMESTAMP
@ -64,38 +54,8 @@
#define CONFIG_LCD_BMP_RLE8
#define CONFIG_KEYBOARD
#define SANDBOX_SERIAL_SETTINGS "stdin=serial,cros-ec-keyb,usbkbd\0" \
"stdout=serial,vidconsole\0" \
"stderr=serial,vidconsole\0"
#else
#define SANDBOX_SERIAL_SETTINGS "stdin=serial\0" \
"stdout=serial,vidconsole\0" \
"stderr=serial,vidconsole\0"
#endif
#define SANDBOX_ETH_SETTINGS "ethaddr=00:00:11:22:33:44\0" \
"eth2addr=00:00:11:22:33:48\0" \
"eth3addr=00:00:11:22:33:45\0" \
"eth4addr=00:00:11:22:33:48\0" \
"eth5addr=00:00:11:22:33:46\0" \
"eth6addr=00:00:11:22:33:47\0" \
"ipaddr=1.2.3.4\0"
#define MEM_LAYOUT_ENV_SETTINGS \
"bootm_size=0x10000000\0" \
"kernel_addr_r=0x1000000\0" \
"fdt_addr_r=0xc00000\0" \
"ramdisk_addr_r=0x2000000\0" \
"scriptaddr=0x1000\0" \
"pxefile_addr_r=0x2000\0"
#define CONFIG_EXTRA_ENV_SETTINGS \
SANDBOX_SERIAL_SETTINGS \
SANDBOX_ETH_SETTINGS \
BOOTENV \
MEM_LAYOUT_ENV_SETTINGS
#ifndef CONFIG_SPL_BUILD
#define CONFIG_SYS_IDE_MAXBUS 1
#define CONFIG_SYS_ATA_IDE0_OFFSET 0

7
include/env.h
View file

@ -133,6 +133,13 @@ int env_get_f(const char *name, char *buf, unsigned int len);
*/
int env_get_yesno(const char *var);
/**
* env_get_autostart() - Check if autostart is enabled
*
* @return true if the "autostart" env var exists and is set to "yes"
*/
bool env_get_autostart(void);
/**
* env_set() - set an environment variable
*

11
include/env_default.h
View file

@ -10,6 +10,10 @@
#include <env_callback.h>
#include <linux/stringify.h>
#ifndef USE_HOSTCC
#include <generated/environment.h>
#endif
#ifdef DEFAULT_ENV_INSTANCE_EMBEDDED
env_t embedded_environment __UBOOT_ENV_SECTION__(environment) = {
ENV_CRC, /* CRC Sum */
@ -110,6 +114,13 @@ const char default_environment[] = {
#if defined(CONFIG_BOOTCOUNT_BOOTLIMIT) && (CONFIG_BOOTCOUNT_BOOTLIMIT > 0)
"bootlimit=" __stringify(CONFIG_BOOTCOUNT_BOOTLIMIT)"\0"
#endif
#ifdef CONFIG_EXTRA_ENV_TEXT
# ifdef CONFIG_EXTRA_ENV_SETTINGS
# error "Your board uses a text-file environment, so must not define CONFIG_EXTRA_ENV_SETTINGS"
# endif
/* This is created in the Makefile */
CONFIG_EXTRA_ENV_TEXT
#endif
#ifdef CONFIG_EXTRA_ENV_SETTINGS
CONFIG_EXTRA_ENV_SETTINGS
#endif

80
scripts/env2string.awk Normal file
View file

@ -0,0 +1,80 @@
# SPDX-License-Identifier: GPL-2.0+
#
# Copyright 2021 Google, Inc
#
# SPDX-License-Identifier: GPL-2.0+
#
# Awk script to parse a text file containing an environment and convert it
# to a C string which can be compiled into U-Boot.
# The resulting output is:
#
# #define CONFIG_EXTRA_ENV_TEXT "<environment here>"
#
# If the input is empty, this script outputs a comment instead.
BEGIN {
# env holds the env variable we are currently processing
env = "";
ORS = ""
}
# Skip empty lines, as these are generated by the clang preprocessor
NF {
# Quote quotes
gsub("\"", "\\\"")
# Is this the start of a new environment variable?
if (match($0, "^([^ \t=][^ =]*)=(.*)$", arr)) {
if (length(env) != 0) {
# Record the value of the variable now completed
vars[var] = env
}
var = arr[1]
env = arr[2]
# Deal with += which concatenates the new string to the existing
# variable
if (length(env) != 0 && match(var, "^(.*)[+]$", var_arr))
{
# Allow var\+=val to indicate that the variable name is
# var+ and this is not actually a concatenation
if (substr(var_arr[1], length(var_arr[1])) == "\\") {
# Drop the backslash
sub(/\\[+]$/, "+", var)
} else {
var = var_arr[1]
env = vars[var] env
}
}
} else {
# Change newline to space
gsub(/^[ \t]+/, "")
# Don't keep leading spaces generated by the previous blank line
if (length(env) == 0) {
env = $0
} else {
env = env " " $0
}
}
}
END {
# Record the value of the variable now completed. If the variable is
# empty it is not set.
if (length(env) != 0) {
vars[var] = env
}
if (length(vars) != 0) {
printf("%s", "#define CONFIG_EXTRA_ENV_TEXT \"")
# Print out all the variables
for (var in vars) {
env = vars[var]
print var "=" vars[var] "\\0"
}
print "\"\n"
}
}

107
test/py/tests/test_env.py
View file

@ -7,6 +7,7 @@
import os
import os.path
from subprocess import call, check_call, CalledProcessError
import tempfile
import pytest
import u_boot_utils
@ -515,3 +516,109 @@ def test_env_ext4(state_test_env):
finally:
if fs_img:
call('rm -f %s' % fs_img, shell=True)
def test_env_text(u_boot_console):
"""Test the script that converts the environment to a text file"""
def check_script(intext, expect_val):
"""Check a test case
Args:
intext: Text to pass to the script
expect_val: Expected value of the CONFIG_EXTRA_ENV_TEXT string, or
None if we expect it not to be defined
"""
with tempfile.TemporaryDirectory() as path:
fname = os.path.join(path, 'infile')
with open(fname, 'w') as inf:
print(intext, file=inf)
result = u_boot_utils.run_and_log(cons, ['awk', '-f', script, fname])
if expect_val is not None:
expect = '#define CONFIG_EXTRA_ENV_TEXT "%s"\n' % expect_val
assert result == expect
else:
assert result == ''
cons = u_boot_console
script = os.path.join(cons.config.source_dir, 'scripts', 'env2string.awk')
# simple script with a single var
check_script('fred=123', 'fred=123\\0')
# no vars
check_script('', None)
# two vars
check_script('''fred=123
ernie=456''', 'fred=123\\0ernie=456\\0')
# blank lines
check_script('''fred=123
ernie=456
''', 'fred=123\\0ernie=456\\0')
# append
check_script('''fred=123
ernie=456
fred+= 456''', 'fred=123 456\\0ernie=456\\0')
# append from empty
check_script('''fred=
ernie=456
fred+= 456''', 'fred= 456\\0ernie=456\\0')
# variable with + in it
check_script('fred+ernie=123', 'fred+ernie=123\\0')
# ignores variables that are empty
check_script('''fred=
fred+=
ernie=456''', 'ernie=456\\0')
# single-character env name
check_script('''f=123
e=456
f+= 456''', 'e=456\\0f=123 456\\0')
# contains quotes
check_script('''fred="my var"
ernie=another"''', 'fred=\\"my var\\"\\0ernie=another\\"\\0')
# variable name ending in +
check_script('''fred\\+=my var
fred++= again''', 'fred+=my var again\\0')
# variable name containing +
check_script('''fred+jane=both
fred+jane+=again
ernie=456''', 'fred+jane=bothagain\\0ernie=456\\0')
# multi-line vars - new vars always start at column 1
check_script('''fred=first
second
\tthird with tab
after blank
confusing=oops
ernie=another"''', 'fred=first second third with tab after blank confusing=oops\\0ernie=another\\"\\0')
# real-world example
check_script('''ubifs_boot=
env exists bootubipart ||
env set bootubipart UBI;
env exists bootubivol ||
env set bootubivol boot;
if ubi part ${bootubipart} &&
ubifsmount ubi${devnum}:${bootubivol};
then
devtype=ubi;
run scan_dev_for_boot;
fi
''',
'ubifs_boot=env exists bootubipart || env set bootubipart UBI; '
'env exists bootubivol || env set bootubivol boot; '
'if ubi part ${bootubipart} && ubifsmount ubi${devnum}:${bootubivol}; '
'then devtype=ubi; run scan_dev_for_boot; fi\\0')