[PATCH v6 0/7] env: Allow environment in text files

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.
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>/env directory called <board>.env (or common.env if you want the same environment for all boards).
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.
Note: this series was originally sent eight years ago:
https://patchwork.ozlabs.org/project/uboot/patch/1382763695-2849-4-git-send-...
It has been updated to work with Kconfig, etc. Some review comments in that patch were infeasible so I have not addressed them. I would like this series to be considered independently, on its merits.
Rather than deal with the complexity of rewriting the distro-boot script, this is disabled for sandbox. The forthcoming bootmethod approach should provide the same functionality without needing the complex scripting in the environment.
Migration needs more thought, although it can be done later. It may be possible to do migrate automatically, using buildman to extract the built-in environmnent from the ELF file.
This would produce a pretty ugly conversion though, since it would drop all the intermediate variables used to create the environment.
Better would be to parse the config.h file, figure out the components of CONFIG_EXTRA_ENV_SETTINGS then output these as separate pieces in the file. It is not clear how easy that would be, nor whether the result would be very pretty. Also the __stringify() macro needs to be handled somehow.
This series is available at u-boot-dm/env-working
Comments welcome.
Changes in v6: - Move all updates to a separate patch - Combine the two env2string.awk patches into one - Move all updates to a separate patch - More updates and improvements - Add new patch to tidy up use of autostart env var
Changes in v5: - Minor updates as suggested by Wolfgang - Explain how to include the common.env file - Explain why variables starting with _ , and / are not supported - Expand the definition of how to declare an environment variable - Explain what happens to empty variables - Update maintainer - Move use of += to this patch - Explain that environment variables may not end in + - Minor updates as suggested by Wolfgang
Changes in v4: - Add new patch to move environment documentation to rST - Move this from being part of configuring U-Boot to part of building it - Don't put the environment in autoconf.mk as it is not needed - Add documentation in rST format instead of README - Drop mention of import/export - Update awk script to ignore blank lines, as generated by clang - Add documentation in rST format instead of README - Add new patch to move environment documentation to rST
Changes in v3: - Adjust Makefile to generate the .inc and .h files in separate fules - Add more detail in the README about the format of .env files - Improve the comment about " in the awk script - Correctly terminate environment files with \n - Define __UBOOT_CONFIG__ when collecting environment files - Add new patch to use a text-based environment for sandbox
Changes in v2: - Move .env file from include/configs to board/ - Use awk script to process environment since it is much easier on the brain - Add information and updated example script to README - Add dependency rule so that the environment is rebuilt when it changes - Add separate patch to enable C preprocessor for environment files - Enable var+=value form to simplify composing variables in multiple steps
Simon Glass (7): binman: Allow timeout to occur in the image or its section sandbox: Drop distro_boot doc: Move environment documentation to rST env: Allow U-Boot scripts to be placed in a .env file sandbox: Use a text-based environment doc: Improve environment documentation bootm: Tidy up use of autostart env var
MAINTAINERS | 7 + Makefile | 39 ++- README | 328 ------------------------ board/sandbox/env/sandbox.env | 25 ++ cmd/bootm.c | 4 +- cmd/elf.c | 3 +- common/bootm_os.c | 5 +- config.mk | 2 + doc/usage/environment.rst | 453 ++++++++++++++++++++++++++++++++++ doc/usage/index.rst | 1 + env/common.c | 7 + env/embedded.c | 1 + include/configs/sandbox.h | 40 --- include/env.h | 7 + include/env_default.h | 8 + scripts/env2string.awk | 56 +++++ tools/binman/ftest.py | 3 +- 17 files changed, 609 insertions(+), 380 deletions(-) create mode 100644 board/sandbox/env/sandbox.env create mode 100644 doc/usage/environment.rst create mode 100644 scripts/env2string.awk

At present testThreadTimeout() assumes that the expected timeout happens first when building the section, but it can just as easily happen at the top-level image. Update the test to cope with both.
Signed-off-by: Simon Glass sjg@chromium.org ---
(no changes since v1)
tools/binman/ftest.py | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/tools/binman/ftest.py b/tools/binman/ftest.py index cea3ebf2b9f..8199a4fc7e0 100644 --- a/tools/binman/ftest.py +++ b/tools/binman/ftest.py @@ -4565,8 +4565,7 @@ class TestFunctional(unittest.TestCase): with self.assertRaises(ValueError) as e: self._DoTestFile('202_section_timeout.dts', test_section_timeout=True) - self.assertIn("Node '/binman/section@0': Timed out obtaining contents", - str(e.exception)) + self.assertIn("Timed out obtaining contents", str(e.exception))
def testTiming(self): """Test output of timing information"""

This is a complicated set of #defines and it is painful to convert to a text file. We can (once pending patches are applied) provide the same functionality with bootmethod. Drop this for sandbox to allow conversion to a text-file environment.
Signed-off-by: Simon Glass sjg@chromium.org ---
(no changes since v1)
include/configs/sandbox.h | 11 ----------- 1 file changed, 11 deletions(-)
diff --git a/include/configs/sandbox.h b/include/configs/sandbox.h index 24c9a84fa35..c19232f202f 100644 --- a/include/configs/sandbox.h +++ b/include/configs/sandbox.h @@ -49,16 +49,6 @@ #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 @@ -103,7 +93,6 @@ #define CONFIG_EXTRA_ENV_SETTINGS \ SANDBOX_SERIAL_SETTINGS \ SANDBOX_ETH_SETTINGS \ - BOOTENV \ MEM_LAYOUT_ENV_SETTINGS
#ifndef CONFIG_SPL_BUILD

Move this from the README to rST format.
Drop i2cfast since it is obviously obsolete and breaks the formatting. Other changes and improvements are in a following patch.
Signed-off-by: Simon Glass sjg@chromium.org ---
Changes in v6: - Move all updates to a separate patch
Changes in v5: - Minor updates as suggested by Wolfgang
Changes in v4: - Add new patch to move environment documentation to rST
README | 328 -------------------------------- doc/usage/environment.rst | 382 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 382 insertions(+), 328 deletions(-) create mode 100644 doc/usage/environment.rst
diff --git a/README b/README index 840b192aae5..f20bc38a41c 100644 --- a/README +++ b/README @@ -2999,334 +2999,6 @@ 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: =======================================
diff --git a/doc/usage/environment.rst b/doc/usage/environment.rst new file mode 100644 index 00000000000..be785a8f717 --- /dev/null +++ b/doc/usage/environment.rst @@ -0,0 +1,382 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +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. + +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 + + +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. + +================= ============== ================ ============== +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 + +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. + +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 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.

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>/env directory called <board>.env (or common.env if you want the same environment for all boards).
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 ---
Changes in v6: - Combine the two env2string.awk patches into one
Changes in v5: - Explain how to include the common.env file - Explain why variables starting with _ , and / are not supported - Expand the definition of how to declare an environment variable - Explain what happens to empty variables - Update maintainer - Move use of += to this patch - Explain that environment variables may not end in +
Changes in v4: - Move this from being part of configuring U-Boot to part of building it - Don't put the environment in autoconf.mk as it is not needed - Add documentation in rST format instead of README - Drop mention of import/export - Update awk script to ignore blank lines, as generated by clang - Add documentation in rST format instead of README
Changes in v3: - Adjust Makefile to generate the .inc and .h files in separate fules - Add more detail in the README about the format of .env files - Improve the comment about " in the awk script - Correctly terminate environment files with \n - Define __UBOOT_CONFIG__ when collecting environment files
Changes in v2: - Move .env file from include/configs to board/ - Use awk script to process environment since it is much easier on the brain - Add information and updated example script to README - Add dependency rule so that the environment is rebuilt when it changes - Add separate patch to enable C preprocessor for environment files - Enable var+=value form to simplify composing variables in multiple steps
MAINTAINERS | 7 +++++ Makefile | 39 ++++++++++++++++++++++++++- config.mk | 2 ++ doc/usage/environment.rst | 54 +++++++++++++++++++++++++++++++++++++ env/embedded.c | 1 + include/env_default.h | 8 ++++++ scripts/env2string.awk | 56 +++++++++++++++++++++++++++++++++++++++ 7 files changed, 166 insertions(+), 1 deletion(-) create mode 100644 scripts/env2string.awk
diff --git a/MAINTAINERS b/MAINTAINERS index 71f468c00a8..36846528368 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -738,6 +738,13 @@ 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 diff --git a/Makefile b/Makefile index f911f703443..635221025da 100644 --- a/Makefile +++ b/Makefile @@ -513,6 +513,7 @@ 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 \ @@ -1785,6 +1786,42 @@ quiet_cmd_sym ?= SYM $@ u-boot.sym: u-boot FORCE $(call if_changed,sym)
+# We expect '<board>.env' but failing that will use 'common.env' +ENV_DIR := $(if $(VENDOR),$(VENDOR)/env,$(BOARD)/env) +ENV_FILE_BOARD := $(srctree)/board/${ENV_DIR}/$(BOARD).env +ENV_FILE_COMMON := $(srctree)/board/${ENV_DIR}/common.env +ENV_FILE := $(if $(wildcard $(ENV_FILE_BOARD)),$(ENV_FILE_BOARD),$(ENV_FILE_COMMON)) + +# Run the environment text file through the preprocessor +quiet_cmd_gen_envp = ENVP $@ + cmd_gen_envp = \ + if [ -f "$(ENV_FILE)" ]; then \ + $(CPP) -P $(CFLAGS) -x assembler-with-cpp -D__ASSEMBLY__ \ + -D__UBOOT_CONFIG__ \ + -I . -I include \ + -I $(srctree)/include -include include/config.h \ + -I$(srctree)/arch/$(ARCH)/include \ + $(ENV_FILE) -o $@; \ + else \ + echo -n >$@ ; \ + fi + +# 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 +include/generated/environment.in: \ + $(if $(wildcard $(ENV_FILE)),$(wildcard $(ENV_FILE)),FORCE) + $(call cmd,gen_envp) + +quiet_cmd_gen_envt = ENVT $@ + cmd_gen_envt = \ + echo -n "#define CONFIG_EXTRA_ENV_TEXT " >$@; \ + awk -f $(srctree)/scripts/env2string.awk $< >>$@ + +$(env_h): include/generated/environment.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) ; @@ -1840,7 +1877,7 @@ 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 $(LDSCRIPT)),) @echo >&2 " Could not find linker script." diff --git a/config.mk b/config.mk index 7bb1fd4ed1b..2595aed218b 100644 --- a/config.mk +++ b/config.mk @@ -50,8 +50,10 @@ endif ifneq ($(BOARD),) ifdef VENDOR BOARDDIR = $(VENDOR)/$(BOARD) +ENVDIR=${vendor}/env else BOARDDIR = $(BOARD) +ENVDIR=${board}/env endif endif ifdef BOARD diff --git a/doc/usage/environment.rst b/doc/usage/environment.rst index be785a8f717..76915484b85 100644 --- a/doc/usage/environment.rst +++ b/doc/usage/environment.rst @@ -16,6 +16,60 @@ environment is erased by accident, a default environment is provided.
Some configuration options can be set using Environment Variables.
+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 (see `CONFIG_EXTRA_ENV_SETTINGS` for details). + +It is also possible to create an environment file with the name +`board/<vendor>/env/<board>.env` for your board. If that file is not present +then U-Boot will look for `board/<vendor>/env/common.env` so that you can +have a common environment for all vendor boards. + +To include the common.env file in your board.env file, use `#include`. + +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. To support this, environment variables may not end +in `+`. + +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/env/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 + +Some configuration options can be set using Environment Variables. + List of environment variables (most likely not complete):
baudrate diff --git a/env/embedded.c b/env/embedded.c index 208553e6af1..9f26e6cad9c 100644 --- a/env/embedded.c +++ b/env/embedded.c @@ -66,6 +66,7 @@ #endif
#define DEFAULT_ENV_INSTANCE_EMBEDDED +#include <config.h> #include <env_default.h>
#ifdef CONFIG_ENV_ADDR_REDUND diff --git a/include/env_default.h b/include/env_default.h index 66e203eb6e4..48190a7c1af 100644 --- a/include/env_default.h +++ b/include/env_default.h @@ -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 */ @@ -112,6 +116,10 @@ const uchar default_environment[] = { #endif #ifdef CONFIG_EXTRA_ENV_SETTINGS CONFIG_EXTRA_ENV_SETTINGS +#endif +#ifdef CONFIG_EXTRA_ENV_TEXT + /* This is created in the Makefile */ + CONFIG_EXTRA_ENV_TEXT #endif "\0" #else /* CONFIG_USE_DEFAULT_ENV_FILE */ diff --git a/scripts/env2string.awk b/scripts/env2string.awk new file mode 100644 index 00000000000..6de3e3dd87e --- /dev/null +++ b/scripts/env2string.awk @@ -0,0 +1,56 @@ +# 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. + +# We output a double quote before starting, and again when we finish so that +# all output is quoted. +BEGIN { + # env holds the env variable we are currently processing + env = ""; + ORS = "" + print """ +} + +# 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($0, "^([^ =][^ =]*)=(.*)", arr)) { + if (length(env) != 0) { + # Record the value of the variable now completed + vars[var] = env + } + var = arr[1] + env = arr[2] + + # Deal with += + if (match(var, "(.*)[+]$", var_arr)) { + var = var_arr[1] + env = vars[var] env + } + } else { + # Change newline to \n + env = env "\n" $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 + } + + # Print out all the variables + for (var in vars) { + print var "=" vars[var] "\0"; + } + print ""\n" +}

Dear Simon Glass,
In message 20211014122254.v6.4.Ie78bfbfca0d01d9cba501e127f446ec48e1f7afe@changeid you wrote:
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>/env directory called <board>.env (or common.env if you want the same environment for all boards).
Argh... did you bother to read my comments? Apparently not.
Thus:
NAKed by: Wolfgang Denk wd@denx.de
I really think your fixed filename proposal does not work well in reality. The file name should be Kconfig configurable. See [1] for details.
[1] https://lists.denx.de/pipermail/u-boot/2021-October/462668.html
Thanks.
Wolfgang Denk

Hi Wolfgang,
On Fri, 15 Oct 2021 at 08:32, Wolfgang Denk wd@denx.de wrote:
Dear Simon Glass,
In message 20211014122254.v6.4.Ie78bfbfca0d01d9cba501e127f446ec48e1f7afe@changeid you wrote:
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>/env directory called <board>.env (or common.env if you want the same environment for all boards).
Argh... did you bother to read my comments? Apparently not.
Thus:
NAKed by: Wolfgang Denk wd@denx.de
I really think your fixed filename proposal does not work well in reality. The file name should be Kconfig configurable. See [1] for details.
[1] https://lists.denx.de/pipermail/u-boot/2021-October/462668.html
Yes I saw that but I forgot to look at it. I think it makes sense - we do that with devicetree, for example.
Is that the only thing holding you back? I haven't seen any positive comments to this series yet...
Regards, Simon

Dear Simon,
In message CAPnjgZ106dBqzJdVYpufp4mztf3_eFoX9isSm=W_c5uDoFJVGA@mail.gmail.com you wrote:
I really think your fixed filename proposal does not work well in reality. The file name should be Kconfig configurable. See [1] for details.
[1] https://lists.denx.de/pipermail/u-boot/2021-October/462668.html
Yes I saw that but I forgot to look at it. I think it makes sense - we do that with devicetree, for example.
Is that the only thing holding you back?
Basically yes - the only other concerns I have is about this += construct which makes the '+' character an illegal character for environment variable names, but only when used at the end of the variable. This is anything but nice or consistent. Iwonder what happens with notations like these:
foo+=bar -> "bar" gets appended to current value of "foo" But what for: foo+=bar or foo+ = bar
?
And please see also my comments about changing the autostart functionality for the user.
I haven't seen any positive comments to this series yet...
Maybe many long-term users of U-Boot don't see the current situation as such a big problem? I have no idea.
Best regards,
Wolfgang Denk

On Mon, Oct 18, 2021 at 01:58:57PM +0200, Wolfgang Denk wrote:
Dear Simon,
In message CAPnjgZ106dBqzJdVYpufp4mztf3_eFoX9isSm=W_c5uDoFJVGA@mail.gmail.com you wrote:
I really think your fixed filename proposal does not work well in reality. The file name should be Kconfig configurable. See [1] for details.
[1] https://lists.denx.de/pipermail/u-boot/2021-October/462668.html
Yes I saw that but I forgot to look at it. I think it makes sense - we do that with devicetree, for example.
Is that the only thing holding you back?
Basically yes - the only other concerns I have is about this += construct which makes the '+' character an illegal character for environment variable names, but only when used at the end of the variable. This is anything but nice or consistent. Iwonder what happens with notations like these:
foo+=bar -> "bar" gets appended to current value of "foo" But what for: foo+=bar or foo+ = bar
?
And please see also my comments about changing the autostart functionality for the user.
Perhaps we should just make "+" an illegal character in the variable name, for consistency?
I haven't seen any positive comments to this series yet...
Maybe many long-term users of U-Boot don't see the current situation as such a big problem? I have no idea.
Considering the number of external to U-Boot projects for dealing with the environment in U-Boot, I don't think that's the case.
Simon, perhaps it's worth poking some of those people off-list with a pointer to your series? Something like this should make integration much easier, for most of the existing OTA solutions that support U-Boot. It should also make it easier for OE/buildroot/etc to explain to users how to modify the environment as well.

Dear Tom,
In message 20211018133728.GQ7964@bill-the-cat you wrote:
And please see also my comments about changing the autostart functionality for the user.
Perhaps we should just make "+" an illegal character in the variable name, for consistency?
And break backward compatibility? I'd rather see a better definition of the syntax of the environment files, plus maybe a more powerful parser.
I mean, there is no technical reason to forbid the '+' character - and then it's only at the end of the variable name.
Hm... I can't find it right now but did I not also read about other restrictions to variable names, like they must noch begin with '_' when using this new tool?
I feel it is wrong to place new restrictions on something that was constant for 21 years, just because our parser cannot parse it...
Best regards,
Wolfgang Denk

On Mon, Oct 18, 2021 at 04:10:34PM +0200, Wolfgang Denk wrote:
Dear Tom,
In message 20211018133728.GQ7964@bill-the-cat you wrote:
And please see also my comments about changing the autostart functionality for the user.
Perhaps we should just make "+" an illegal character in the variable name, for consistency?
And break backward compatibility? I'd rather see a better definition of the syntax of the environment files, plus maybe a more powerful parser.
Are there examples today of scripts that use "+" in the variable names? That maybe someone wrote a custom an private thing that uses + in the name isn't the best argument. Someone saying that did would be better.
I mean, there is no technical reason to forbid the '+' character - and then it's only at the end of the variable name.
Of course yes, if we can just make the parser handle it, without it also being a tricky nightmare, that's the better solution.
Hm... I can't find it right now but did I not also read about other restrictions to variable names, like they must noch begin with '_' when using this new tool?
Any invalid characters need to be clearly documented, if they aren't, yes.
I feel it is wrong to place new restrictions on something that was constant for 21 years, just because our parser cannot parse it...
Sure. But if it's also the case that for 21 years no one has been using foo+bar, baz+, etc, in their variable names, maybe we just document that's not valid and move on?

Dear Tom,
In message 20211018142404.GR7964@bill-the-cat you wrote:
Perhaps we should just make "+" an illegal character in the variable name, for consistency?
And break backward compatibility? I'd rather see a better definition of the syntax of the environment files, plus maybe a more powerful parser.
Are there examples today of scripts that use "+" in the variable names?
None that I know of.
That maybe someone wrote a custom an private thing that uses + in the name isn't the best argument. Someone saying that did would be better.
Yes, I know. But then, changing existing APIs is not nice.
Of course yes, if we can just make the parser handle it, without it also being a tricky nightmare, that's the better solution.
Exactly.
Hm... I can't find it right now but did I not also read about other restrictions to variable names, like they must noch begin with '_' when using this new tool?
Any invalid characters need to be clearly documented, if they aren't, yes.
So far, only NUL and '=' were impossible to use in a variable name.
I feel it is wrong to place new restrictions on something that was constant for 21 years, just because our parser cannot parse it...
Sure. But if it's also the case that for 21 years no one has been using foo+bar, baz+, etc, in their variable names, maybe we just document that's not valid and move on?
We cannot know what people have been using in their environemnts. Even for those boards that are in mainline, the environment settings used in real life are often totally different.
Best regards,
Wolfgang Denk

Hi Wolfgang,
On Mon, 18 Oct 2021 at 08:10, Wolfgang Denk wd@denx.de wrote:
Dear Tom,
In message 20211018133728.GQ7964@bill-the-cat you wrote:
And please see also my comments about changing the autostart functionality for the user.
Perhaps we should just make "+" an illegal character in the variable name, for consistency?
And break backward compatibility? I'd rather see a better definition of the syntax of the environment files, plus maybe a more powerful parser.
I mean, there is no technical reason to forbid the '+' character - and then it's only at the end of the variable name.
Hm... I can't find it right now but did I not also read about other restrictions to variable names, like they must noch begin with '_' when using this new tool?
Yes but I took that out (I think in v6). I'll update the commit message.
I feel it is wrong to place new restrictions on something that was constant for 21 years, just because our parser cannot parse it...
We need the + thing and perhaps we should ask people to avoid punctuation, etc? But for now I'm not requiring it in this series, apart from +
Regards, Simon

Dear Simon,
In message CAPnjgZ2FGUCFDbSU8TvsV5p-5p3aqnwf7ju28xMKB__w2-ATGw@mail.gmail.com you wrote:
Hm... I can't find it right now but did I not also read about other restrictions to variable names, like they must noch begin with '_' when using this new tool?
Yes but I took that out (I think in v6). I'll update the commit message.
Why exactly is this now forbidden, too?
I feel it is wrong to place new restrictions on something that was constant for 21 years, just because our parser cannot parse it...
We need the + thing and perhaps we should ask people to avoid punctuation, etc? But for now I'm not requiring it in this series, apart from +
Punctuation? Well, we already have ".flags", so at least here we do have a real life use case.
I really would like to avoid new restictions of variable names, especially as I cannot see any good reason for it - yes, your awk script cannot handle this situation, but I tend to belive the fix is in a better parser than in placing restrictions on the input data.
Best regards,
Wolfgang Denk

Hi Wolfgang,
On Mon, 18 Oct 2021 at 05:59, Wolfgang Denk wd@denx.de wrote:
Dear Simon,
In message CAPnjgZ106dBqzJdVYpufp4mztf3_eFoX9isSm=W_c5uDoFJVGA@mail.gmail.com you wrote:
I really think your fixed filename proposal does not work well in reality. The file name should be Kconfig configurable. See [1] for details.
[1] https://lists.denx.de/pipermail/u-boot/2021-October/462668.html
Yes I saw that but I forgot to look at it. I think it makes sense - we do that with devicetree, for example.
Is that the only thing holding you back?
Basically yes - the only other concerns I have is about this += construct which makes the '+' character an illegal character for environment variable names, but only when used at the end of the variable. This is anything but nice or consistent. Iwonder what happens with notations like these:
foo+=bar -> "bar" gets appended to current value of "foo"
But what for: foo+=bar or foo+ = bar
?
Can we just ban + ?
In the above, foo+ gives an unknown escape sequence from the C preprocessor, then the whole line is ignored by the script
foo+ = bar produes a variable called "foo+ " in the environment with the value " bar" so you probably don't want that.
And please see also my comments about changing the autostart functionality for the user.
Yes I saw that and I think it is OK to change it. What do you think?
I haven't seen any positive comments to this series yet...
Maybe many long-term users of U-Boot don't see the current situation as such a big problem? I have no idea.
My original motivation was the complexity of getting the env you want using #define
My current motivation is to complete the CONFIG migration, now in its 8th year.
Regards, Simon

Dear Simon,
In message CAPnjgZ15KavTBZoML7dv_EaRJMyJvbA=kmY3Bgz4AeygwEppuQ@mail.gmail.com you wrote:
Can we just ban + ?
Why? Just because your awk script is a lousy parser?
In the above, foo+ gives an unknown escape sequence from the C preprocessor, then the whole line is ignored by the script
Really?
-> cat foo.c #define A ampersand #define B berta
int foo = A + B ; -> gcc -E foo.c # 0 "foo.c" # 0 "<built-in>" # 0 "<command-line>" # 1 "/usr/include/stdc-predef.h" 1 3 4 # 0 "<command-line>" 2 # 1 "foo.c"
int foo = ampersand + berta ;
I do not see any such error message?
foo+ = bar produes a variable called "foo+ " in the environment with the value " bar" so you probably don't want that.
This is only because your "parser" is very primitive and sensitive even to minimal white space changes.
My original motivation was the complexity of getting the env you want using #define
My current motivation is to complete the CONFIG migration, now in its 8th year.
I fully understand your motivation and appreciate your efforts.
Best regards,
Wolfgang Denk

Hi Wolfgang,
On Tue, 19 Oct 2021 at 04:46, Wolfgang Denk wd@denx.de wrote:
Dear Simon,
In message CAPnjgZ15KavTBZoML7dv_EaRJMyJvbA=kmY3Bgz4AeygwEppuQ@mail.gmail.com you wrote:
Can we just ban + ?
Why? Just because your awk script is a lousy parser?
In the above, foo+ gives an unknown escape sequence from the C preprocessor, then the whole line is ignored by the script
Really?
-> cat foo.c #define A ampersand #define B berta
int foo = A + B ; -> gcc -E foo.c # 0 "foo.c" # 0 "<built-in>" # 0 "<command-line>" # 1 "/usr/include/stdc-predef.h" 1 3 4 # 0 "<command-line>" 2 # 1 "foo.c"
int foo = ampersand + berta ;
I do not see any such error message?
I thought you were trying to use + at the end of a variable.
I used:
fred+=aaa
and got
cc1: warning: unknown escape sequence: '=''
You can try it yourself by editing sandbox.env in the u-boot-dm/env-working tree.
foo+ = bar produes a variable called "foo+ " in the environment with the value " bar" so you probably don't want that.
This is only because your "parser" is very primitive and sensitive even to minimal white space changes.
Agreed.
My original motivation was the complexity of getting the env you want using #define
My current motivation is to complete the CONFIG migration, now in its 8th year.
I fully understand your motivation and appreciate your efforts.
OK, so what exactly is needed here? I can do the above tweaks and the cover letter, but what else?
Regards, Simon

Dear Simon,
In message CAPnjgZ3KS06_cy8mLL2V-ezqZYO6QEecz2C78hVaUQAnAz0fNg@mail.gmail.com you wrote:
I thought you were trying to use + at the end of a variable.
I used:
fred+=aaa
and got
cc1: warning: unknown escape sequence: '=''
You can try it yourself by editing sandbox.env in the u-boot-dm/env-working tree.
Hmmm...
-> cat foo.c #define A ampersand #define B berta
foo+=B; -> gcc -E foo.c # 0 "foo.c" # 0 "<built-in>" # 0 "<command-line>" # 1 "/usr/include/stdc-predef.h" 1 3 4 # 0 "<command-line>" 2 # 1 "foo.c"
foo+=berta;
-> cat bar.c fred+=aaa -> gcc -E bar.c # 0 "bar.c" # 0 "<built-in>" # 0 "<command-line>" # 1 "/usr/include/stdc-predef.h" 1 3 4 # 0 "<command-line>" 2 # 1 "bar.c" fred+=aaa
I do not see this problem...
Best regards,
Wolfgang Denk

Hi Wolfgang,
On Tue, 19 Oct 2021 at 10:09, Wolfgang Denk wd@denx.de wrote:
Dear Simon,
In message CAPnjgZ3KS06_cy8mLL2V-ezqZYO6QEecz2C78hVaUQAnAz0fNg@mail.gmail.com you wrote:
I thought you were trying to use + at the end of a variable.
I used:
fred+=aaa
and got
cc1: warning: unknown escape sequence: '=''
You can try it yourself by editing sandbox.env in the u-boot-dm/env-working tree.
Hmmm...
-> cat foo.c #define A ampersand #define B berta
foo+=B; -> gcc -E foo.c # 0 "foo.c" # 0 "<built-in>" # 0 "<command-line>" # 1 "/usr/include/stdc-predef.h" 1 3 4 # 0 "<command-line>" 2 # 1 "foo.c"
foo+=berta;
-> cat bar.c fred+=aaa -> gcc -E bar.c # 0 "bar.c" # 0 "<built-in>" # 0 "<command-line>" # 1 "/usr/include/stdc-predef.h" 1 3 4 # 0 "<command-line>" 2 # 1 "bar.c" fred+=aaa
I do not see this problem...
Would you mind actually trying it in the env file, as I suggested?
Regards, Simon

Use a text file for the environment instead of the #define settings.
Signed-off-by: Simon Glass sjg@chromium.org ---
(no changes since v3)
Changes in v3: - Add new patch to use a text-based environment for sandbox
board/sandbox/env/sandbox.env | 25 +++++++++++++++++++++++++ include/configs/sandbox.h | 29 ----------------------------- 2 files changed, 25 insertions(+), 29 deletions(-) create mode 100644 board/sandbox/env/sandbox.env
diff --git a/board/sandbox/env/sandbox.env b/board/sandbox/env/sandbox.env new file mode 100644 index 00000000000..0f8d95b8db0 --- /dev/null +++ b/board/sandbox/env/sandbox.env @@ -0,0 +1,25 @@ +stdin=serial +#ifdef CONFIG_SANDBOX_SDL +stdin+=,cros-ec-keyb,usbkbd +#endif +stdout=serial,vidconsole +stderr=serial,vidconsole + +ethaddr=00:00:11:22:33:44 +eth2addr=00:00:11:22:33:48 +eth3addr=00:00:11:22:33:45 +eth4addr=00:00:11:22:33:48 +eth5addr=00:00:11:22:33:46 +eth6addr=00:00:11:22:33:47 +ipaddr=1.2.3.4 + +/* + * 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 diff --git a/include/configs/sandbox.h b/include/configs/sandbox.h index c19232f202f..c703a1330c0 100644 --- a/include/configs/sandbox.h +++ b/include/configs/sandbox.h @@ -64,37 +64,8 @@ #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 \ - MEM_LAYOUT_ENV_SETTINGS - #ifndef CONFIG_SPL_BUILD #define CONFIG_SYS_IDE_MAXBUS 1 #define CONFIG_SYS_ATA_IDE0_OFFSET 0

Make various updates suggested during review of the rST conversion.
Signed-off-by: Simon Glass sjg@chromium.org Suggested-by: Wolfgang Denk wd@denx.de ---
Changes in v6: - Move all updates to a separate patch - More updates and improvements
Changes in v5: - Minor updates as suggested by Wolfgang
Changes in v4: - Add new patch to move environment documentation to rST
doc/usage/environment.rst | 35 ++++++++++++++++++++++++++--------- doc/usage/index.rst | 1 + 2 files changed, 27 insertions(+), 9 deletions(-)
diff --git a/doc/usage/environment.rst b/doc/usage/environment.rst index 76915484b85..ef9cd20715a 100644 --- a/doc/usage/environment.rst +++ b/doc/usage/environment.rst @@ -5,16 +5,20 @@ Environment Variables
U-Boot supports user configuration using Environment Variables which -can be made persistent by saving to Flash memory. +can be made persistent by saving to persistent storage, for example flash +memory.
-Environment Variables are set using "setenv", printed using -"printenv", and saved to Flash using "saveenv". Using "setenv" +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 options can be set using Environment Variables. +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).
The default environment is created in `include/env_default.h`, and can be augmented by various `CONFIG` defines. See that file for details. In @@ -68,18 +72,25 @@ Example:: echo CONFIG_SYS_BOARD boot failed - please check your image echo Load address is CONFIG_SYS_LOAD_ADDR
-Some configuration options can be set using Environment Variables. +Some 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. +
List of environment variables (most likely not complete):
baudrate - see CONFIG_BAUDRATE + Current baud rate used by the serial console. The built-in value is set by + CONFIG_BAUDRATE (see `drivers/serial/Kconfig`)
bootdelay - see CONFIG_BOOTDELAY + Current autoboot delay. The built-in value is set by CONFIG_BOOTDELAY (see + `common/Kconfig`)
bootcmd - see CONFIG_BOOTCOMMAND + Defines a command string that is automatically executed when no character + is read on the console interface within a cetain boot delay after reset. + The built-in value is set by CONFIG_BOOTCOMMAND (see `common/Kconfig`)
bootargs Boot arguments when booting an RTOS image @@ -125,7 +136,7 @@ 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 + load any image using TFTP or DHCP.
autostart if set to "yes", an image loaded using the "bootp", @@ -291,6 +302,8 @@ vlan 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 @@ -332,6 +345,10 @@ flash or offset in NAND flash. 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 ================= ============== ================ ============== diff --git a/doc/usage/index.rst b/doc/usage/index.rst index 356f2a56181..1a79d1c03eb 100644 --- a/doc/usage/index.rst +++ b/doc/usage/index.rst @@ -5,6 +5,7 @@ Use U-Boot :maxdepth: 1
dfu + environment fdt_overlays fit netconsole

This has different semantics in different places. Go with the bootm method and put it in a common function so that the behaviour is consistent in U-Boot. Update the docs.
Signed-off-by: Simon Glass sjg@chromium.org Suggested-by: Wolfgang Denk wd@denx.de ---
Changes in v6: - Add new patch to tidy up use of autostart env var
cmd/bootm.c | 4 +--- cmd/elf.c | 3 +-- common/bootm_os.c | 5 +---- doc/usage/environment.rst | 4 ++-- env/common.c | 7 +++++++ include/env.h | 7 +++++++ 6 files changed, 19 insertions(+), 11 deletions(-)
diff --git a/cmd/bootm.c b/cmd/bootm.c index 92468d09a1f..b82a872a86c 100644 --- a/cmd/bootm.c +++ b/cmd/bootm.c @@ -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; diff --git a/cmd/elf.c b/cmd/elf.c index d75b21461c2..2b33c50bd02 100644 --- a/cmd/elf.c +++ b/cmd/elf.c @@ -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); diff --git a/common/bootm_os.c b/common/bootm_os.c index 39623f9126b..f30dcebbf7d 100644 --- a/common/bootm_os.c +++ b/common/bootm_os.c @@ -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; } diff --git a/doc/usage/environment.rst b/doc/usage/environment.rst index ef9cd20715a..99285115f29 100644 --- a/doc/usage/environment.rst +++ b/doc/usage/environment.rst @@ -144,8 +144,8 @@ autostart 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 + If unset, or set to anything other than "yes", 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. diff --git a/env/common.c b/env/common.c index 81e9e0b2aaf..ef9502a34f7 100644 --- a/env/common.c +++ b/env/common.c @@ -47,6 +47,13 @@ int env_get_yesno(const char *var) 1 : 0; }
+bool env_get_autostart(void) +{ + const char *val = env_get("autostart"); + + return val && !strcmp(val, "yes"); +} + /* * Look up the variable from the default environment */ diff --git a/include/env.h b/include/env.h index d5e2bcb530f..fdad495691f 100644 --- a/include/env.h +++ b/include/env.h @@ -143,6 +143,13 @@ 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 *

Dear Simon Glass,
In message 20211014182257.468649-6-sjg@chromium.org you wrote:
This has different semantics in different places. Go with the bootm method and put it in a common function so that the behaviour is consistent in U-Boot. Update the docs.
Signed-off-by: Simon Glass sjg@chromium.org Suggested-by: Wolfgang Denk wd@denx.de
It should be noted that this commit changes the behaviour of U-Boot for "autostart" users, thus it has the potential of breaking existent systems.
The problematic cases are in do_bootelf() [cmd/elf.c] and do_bootm_standalone() [common/bootm_os.c]; the 3rd place where this is used - bootm_maybe_autostart() [cmd/bootm.c] - does not change.
Or am I missing something?
Best regards,
Wolfgang Denk

Hi Wolfgang,
On Fri, 15 Oct 2021 at 08:45, Wolfgang Denk wd@denx.de wrote:
Dear Simon Glass,
In message 20211014182257.468649-6-sjg@chromium.org you wrote:
This has different semantics in different places. Go with the bootm method and put it in a common function so that the behaviour is consistent in U-Boot. Update the docs.
Signed-off-by: Simon Glass sjg@chromium.org Suggested-by: Wolfgang Denk wd@denx.de
It should be noted that this commit changes the behaviour of U-Boot for "autostart" users, thus it has the potential of breaking existent systems.
The problematic cases are in do_bootelf() [cmd/elf.c] and do_bootm_standalone() [common/bootm_os.c]; the 3rd place where this is used - bootm_maybe_autostart() [cmd/bootm.c] - does not change.
Or am I missing something?
Just to reply here, I sent an updated patch explaining that this does in fact change behaviour, but only in a case that seems safe enough.
Regards, Simon
participants (3)
-
Simon Glass
-
Tom Rini
-
Wolfgang Denk