This patch set provides enough to demo how the Kconfig fragment based defconfigs could be used to simplify both generating and managing the configs used to build Linaro kernels.
This is for the kernel config managment tool and dependent bluprints: https://blueprints.launchpad.net/linux-linaro/+spec/other-kernel-config-management-tool The basic idea is to use a Kconfig fragment to generate the per-board defconfigs. The Kconfig fragments contain a meta-option that defaults to yes, which then selects the needed config values to enable a system. This has been proposed by others, and we're using Stephen Rothwell's initial patch to start things off. Once we have the infrasturcture to use Kconfig fragments for defconfigs we had to overcome some limitations: 1) We cannot select items from a choice block 2) We need a way to select for values and modules. Limitation #1 is resolved by a patch to the kbuild system I made. Limitation #2 is unsolved, but Jason Hui found a workaround that is sufficient. Basically we can just redefine the default with a short declaration: config VAL default 256 or config VAL default m With these two solutions, I went forward generating basic Kconfig fragments for omap3, imx51 and vexpress. Getting per-board defconfigs is only of limited value, because we also want to be able to have a common policy settings for Linaro kernels. Many distros run into this problem, and use .config fragments which are then assembled at package build time. My solution is to have a Kconfig.distro file, which is patched with Distro specific policy config, such as which filesystems should be enabled, networking policy, debug options, or periphrial driver modules that should be enabled. Basically anything that isn't hardware specific (by that I mean, part of the architecture or wired on the board). >From there, I add in as much of the generic Linaro config policy as I could, utilizing the config files that were used to build the omap3, imx51 and vexpress hardware packs. Since the Linaro config polciy is not unified at this point (in other words, each board has totally different set of generic policy options configured). I added the per target differences into the board kconfig fragments. Ideally we can review and settle down on specific linaro config policy and this generic per-board stuff can go away. These are initial and rough patches, but are the result of lots of painful manual labor to match the Linaro .configs as closely as possible. There are a few remaining issues, but these can probably be worked around: 1) Omap has a strange tristate choice option for the usb gadget options. So you can only pick one, or you can pick multiple items as modules. My choice selection patch doesn't yet address this. I need to see how common this style of choice is and see if we can either just make it a non-choice options block or if other fixes are needed. 2) Not having a module selction is a little painful, as the module "default m" entries are numerous and annoyingly separate from the meta-config selects. 3) The Kconfig.distro file should be probably broken up into policy topics, like networking, filesystems, peripherials, etc. 4) The current board Kconfig fragments are named slightly differently from the standard defconfigs to allow testing with both. That will need to be fixed, and the old defconfigs removed prior to submitting. 5) The igep, overo, and panda configs all use the same omap3 config according to the hwpacks. I'm not sure I believe that, but went along with it to get this out the door. Many thanks to Jason for his help figuring out an approach here. Feedback and thoughts would be greatly appreciated. thanks -john CC: Grant Likely <grant.lik...@secretlab.ca> CC: Jason Hui <jason....@linaro.org> CC: patc...@linaro.org John Stultz (11): kbuild: Allow configs from choice blocks to be selected. kbuild: Use kconfig defaults as defconfig starting point kbuild: Avoid kconfig fragment defconfigs from having odd config order Add blank Kconfig.distro fragment file Initial omap3 Kconfig fragment Initial imx51 defconfig fragment Add initial vexpress defconfig fragment Add Linaro config policy to Kconfig.distro omap3 kconfig fragment changes to align with linaro build Update imx51 to better match linaro configs Update vexpress to be closer to linaro config Stephen Rothwell (1): kbuild: Enable building defconfigs from Kconfig files Kconfig.distro | 1754 +++++++++++++++++++++++++++++ arch/arm/configs/Kconfig.imx51 | 503 +++++++++ arch/arm/configs/Kconfig.omap3 | 2430 ++++++++++++++++++++++++++++++++++++++++ arch/arm/configs/Kconfig.vexp | 234 ++++ scripts/kconfig/Makefile | 16 +- scripts/kconfig/symbol.c | 15 +- 6 files changed, 4949 insertions(+), 3 deletions(-) create mode 100644 Kconfig.distro create mode 100644 arch/arm/configs/Kconfig.imx51 create mode 100644 arch/arm/configs/Kconfig.omap3 create mode 100644 arch/arm/configs/Kconfig.vexp -- 1.7.3.2.146.gca209 _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
