qconfig: Update the documentation

Update qconfig's documentation to better reflect its new purpose in life.

Signed-off-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Simon Glass 2023-09-23 13:44:16 -06:00
parent 519637929b
commit 4840b71bb0
2 changed files with 47 additions and 115 deletions

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@ -88,7 +88,7 @@ Refactoring
checkpatch
coccinelle
moveconfig
qconfig
Code quality
------------

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@ -1,148 +1,87 @@
.. SPDX-License-Identifier: GPL-2.0+
moveconfig - Migrating and querying CONFIG options
==================================================
qconfig - Querying CONFIG options
=================================
Since Kconfig was introduced to U-Boot, we have worked on moving
config options from headers to Kconfig (defconfig).
It is not possible to see all the CONFIG options used by a board without
building its `.config` file. This tool allows this to be done efficiently for
all boards, or a subset, writing the results to a unified database file.
This tool intends to help this tremendous work.
This database can be queried, to find boards which used a certain combination
of options, to aid in discovering Kconfig options which imply others.
Installing
----------
The tool also permits syncing of defconfigs, which corrects the ordering and
drops options which are implied by others.
Finally, it allows scanning the source code to look for inconsistencies in the
use of Kconfig options.
Installation
------------
You may need to install 'python3-asteval' for the 'asteval' module.
Usage
-----
First, you must edit the Kconfig to add the menu entries for the configs
you are moving.
Then run this tool giving CONFIG names you want to move.
For example, if you want to move CONFIG_CMD_USB and CONFIG_TEXT_BASE,
simply type as follows::
$ tools/moveconfig.py CONFIG_CMD_USB CONFIG_TEXT_BASE
The tool walks through all the defconfig files and move the given CONFIGs.
The log is also displayed on the terminal.
The log is printed for each defconfig as follows::
<defconfig_name>
<action1>
<action2>
<action3>
...
`<defconfig_name>` is the name of the defconfig.
`<action*>` shows what the tool did for that defconfig.
It looks like one of the following:
- Move 'CONFIG\_... '
This config option was moved to the defconfig
- CONFIG\_... is not defined in Kconfig. Do nothing.
The entry for this CONFIG was not found in Kconfig. The option is not
defined in the config header, either. So, this case can be just skipped.
- CONFIG\_... is not defined in Kconfig (suspicious). Do nothing.
This option is defined in the config header, but its entry was not found
in Kconfig.
There are two common cases:
- You forgot to create an entry for the CONFIG before running
this tool, or made a typo in a CONFIG passed to this tool.
- The entry was hidden due to unmet 'depends on'.
The tool does not know if the result is reasonable, so please check it
manually.
- 'CONFIG\_...' is the same as the define in Kconfig. Do nothing.
The define in the config header matched the one in Kconfig.
We do not need to touch it.
- Compiler is missing. Do nothing.
The compiler specified for this architecture was not found
in your PATH environment.
(If -e option is passed, the tool exits immediately.)
- Failed to process.
An error occurred during processing this defconfig. Skipped.
(If -e option is passed, the tool exits immediately on error.)
Finally, you will be asked, Clean up headers? [y/n]:
If you say 'y' here, the unnecessary config defines are removed
from the config headers (include/configs/\*.h).
It just uses the regex method, so you should not rely on it.
Just in case, please do 'git diff' to see what happened.
How does it work?
-----------------
This tool runs configuration and builds include/autoconf.mk for every
defconfig. The config options defined in Kconfig appear in the .config
file (unless they are hidden because of unmet dependency.)
When building a database (`-b`), this tool runs configuration and builds
include/autoconf.mk for every defconfig. The config options defined in Kconfig
appear in the .config file (unless they are hidden because of unmet dependency.)
On the other hand, the config options defined by board headers are seen
in include/autoconf.mk. The tool looks for the specified options in both
of them to decide the appropriate action for the options. If the given
config option is found in the .config, but its value does not match the
one from the board header, the config option in the .config is replaced
with the define in the board header. Then, the .config is synced by
"make savedefconfig" and the defconfig is updated with it.
in include/autoconf.mk.
For faster processing, this tool handles multi-threading. It creates
When resyncing defconfigs (`-s`) the .config is synced by "make savedefconfig"
and the defconfig is updated with it.
For faster processing, this tool is multi-threaded. It creates
separate build directories where the out-of-tree build is run. The
temporary build directories are automatically created and deleted as
needed. The number of threads are chosen based on the number of the CPU
cores of your system although you can change it via -j (--jobs) option.
Note that `*.config` fragments are not supported.
Toolchains
----------
Appropriate toolchain are necessary to generate include/autoconf.mk
Appropriate toolchains are necessary to generate include/autoconf.mk
for all the architectures supported by U-Boot. Most of them are available
at the kernel.org site, some are not provided by kernel.org. This tool uses
the same tools as buildman, so see that tool for setup (e.g. --fetch-arch).
at the kernel.org site. This tool uses the same tools as
:doc:`../build/buildman`, so you can use `buildman --fetch-arch` to fetch
toolchains.
Tips and trips
--------------
Examples
--------
To sync only X86 defconfigs::
./tools/moveconfig.py -s -d <(grep -l X86 configs/*)
./tools/qconfig.py -s -d <(grep -l X86 configs/*)
or::
grep -l X86 configs/* | ./tools/moveconfig.py -s -d -
grep -l X86 configs/* | ./tools/qconfig.py -s -d -
To process CONFIG_CMD_FPGAD only for a subset of configs based on path match::
ls configs/{hrcon*,iocon*,strider*} | \
./tools/moveconfig.py -Cy CONFIG_CMD_FPGAD -d -
./tools/qconfig.py -C CONFIG_CMD_FPGAD -d -
Finding boards with particular CONFIG combinations
--------------------------------------------------
You can use `moveconfig.py` to figure out which boards have a CONFIG enabled, or
You can use `qconfig.py` to figure out which boards have a CONFIG enabled, or
which do not. To use it, first build a database::
./tools/moveconfig.py -b
./tools/qconfig.py -b
Then you can run queries using the `-f` flag followed by a list of CONFIG terms.
Each term is CONFIG name, with or without a tilde (~) prefix. The tool searches
for boards which match the CONFIG name, or do not match if tilde is used. For
example, to find boards which enabled CONFIG_SCSI but not CONFIG_BLK::
tools/moveconfig.py -f SCSI ~BLK
tools/qconfig.py -f SCSI ~BLK
3 matches
pg_wcom_seli8_defconfig highbank_defconfig pg_wcom_expu1_defconfig
@ -158,11 +97,11 @@ each of the x86 defconfig files.
This tool can help find such configs. To use it, first build a database::
./tools/moveconfig.py -b
./tools/qconfig.py -b
Then try to query it::
./tools/moveconfig.py -i CONFIG_I8042_KEYB
./tools/qconfig.py -i CONFIG_I8042_KEYB
CONFIG_I8042_KEYB found in 33/5155 defconfigs
28 : CONFIG_X86
28 : CONFIG_SA_PCIEX_LENGTH
@ -193,12 +132,12 @@ indicates that CONFIG_I8042_KEYB is not needed for the remaining 5 boards. Many
of the options listed are not suitable as they are not related. E.g. it would be
odd for CONFIG_RAMBASE to imply CONFIG_I8042_KEYB.
Using this search you can reduce the size of moveconfig patches.
Using this search you can reduce the size of qconfig patches.
You can automatically add 'imply' statements in the Kconfig with the -a
option::
./tools/moveconfig.py -s -i CONFIG_SCSI \
./tools/qconfig.py -s -i CONFIG_SCSI \
-a CONFIG_ARCH_LS1021A,CONFIG_ARCH_LS1043A
This will add 'imply SCSI' to the two CONFIG options mentioned, assuming that
@ -220,7 +159,7 @@ the size of their defconfig files.
If you want to add an 'imply' to every imply config in the list, you can use::
./tools/moveconfig.py -s -i CONFIG_SCSI -a all
./tools/qconfig.py -s -i CONFIG_SCSI -a all
To control which ones are displayed, use -I <list> where list is a list of
options (use '-I help' to see possible options and their meaning).
@ -230,7 +169,7 @@ To skip showing you options that already have an 'imply' attached, use -A.
When you have finished adding 'imply' options you can regenerate the
defconfig files for affected boards with something like::
git show --stat | ./tools/moveconfig.py -s -d -
git show --stat | ./tools/qconfig.py -s -d -
This will regenerate only those defconfigs changed in the current commit.
If you start with (say) 100 defconfigs being changed in the commit, and add
@ -241,9 +180,9 @@ number of defconfigs changed in the commit.
Available options
-----------------
-c, --color
Surround each portion of the log with escape sequences to display it
in color on the terminal.
--nocolour
Disables colouring of output. This is normally used when writing to a
terminal.
-C, --commit
Create a git commit with the changes when the operation is complete. A
@ -275,9 +214,6 @@ Available options
because SPL related options (mostly prefixed with CONFIG_SPL\_) are
sometimes blocked by CONFIG_SPL_BUILD ifdef conditionals.
-H, --headers-only
Only cleanup the headers; skip the defconfig processing
-j, --jobs
Specify the number of threads to run simultaneously. If not specified,
the number of threads is the same as the number of CPU cores.
@ -293,10 +229,6 @@ Available options
-v, --verbose
Show any build errors as boards are built
-y, --yes
Instead of prompting, automatically go ahead with all operations. This
includes cleaning up headers, the config whitelist and the README.
To see the complete list of supported options, run::
tools/moveconfig.py -h
tools/qconfig.py -h