From 3c28d014b7b6d49f2daa33d03008a5355f7aa305 Mon Sep 17 00:00:00 2001 From: Patrick Georgi Date: Thu, 5 Feb 2015 23:36:32 +0100 Subject: documentation: begin documenting our use of git submodules git submodules have some surprising behaviour, and we make full use of it. Start building a canonical resource for that so developers can spend their time on better things than on fighting git. Change-Id: I5aa721e9b0acb2912a057858fd23a1d59d845ed1 Signed-off-by: Patrick Georgi Reviewed-on: http://review.coreboot.org/8371 Tested-by: build bot (Jenkins) Reviewed-by: Paul Menzel Reviewed-by: Stefan Reinauer Reviewed-by: Alexandru Gagniuc --- documentation/submodules.txt | 46 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 documentation/submodules.txt diff --git a/documentation/submodules.txt b/documentation/submodules.txt new file mode 100644 index 0000000000..631e351303 --- /dev/null +++ b/documentation/submodules.txt @@ -0,0 +1,46 @@ +Use of git submodules in coreboot +================================= +coreboot uses git submodules to keep certain parts of the tree separate, +with two major use cases: + +First, we use a vendor tool by NVIDIA for systems based on their SoC +and since they publish it through git, we can just import it into our +tree using submodules. + +Second, lots of boards these days require binaries and we want to keep +them separate from coreboot proper to clearly delineate shiny Open Source +from ugly blobs. +Since we don't want to impose blobs on users who really don't need them, +that repository is only downloaded and checked out on explicit request. + +Handling submodules +------------------- +For the most part, submodules should be automatically checked out on the +first execution of the coreboot Makefile. + +To manually fetch all repositories (eg. when you want to prepare the tree +for archiving, or to use it without network access), run + + $ git submodule update --init --checkout + +This also checks out the binaries below `3rdparty/` + +Mirroring coreboot +------------------ +When running a coreboot mirror to checkout from, for full operation, you +should also mirror the blobs and nvidia-cbootimage repository, and place +them in the same directory as the coreboot repository mirror. + +That is, when residing in coreboot's repository, `cd ../blobs.git` +should move you to the blobs repository. + +With that, no matter what the URL of your coreboot repository is, the +git client (of a sufficiently new version) is able to pick up the other +repositories transparently. + +Minimum requirements +-------------------- +git needs to be able to handle relative paths to submodule repositories, +and it needs to know about non-automatic submodules. + +For these features, we require git version 1.7.6.1 or newer. -- cgit v1.2.3