buildman: Incorporate the genboardscfg.py tool

Bring this tool into buildman, so we don't have to run it separately. The
board.cfg file is still produced as part of the build, to save time when
doing another build in the same working directory. If it is out of date
with respect to the Kconfig, it is updated.

Time to regenerate on a recent single-thread machine is 4.6s (1.3s on a
32-thread machine), so we do need some sort of cache if we want buildman
to be useful on incremental builds. We could use Python's pickle format
but:

- it seems useful to allow boards.cfg to be regenerated, at least for a
  while, in case other tools use it
- it is possible to grep the file easily, e.g. to find boards which use
  a particular SoC (similar to 'buildman -nv <soc>'

Signed-off-by: Simon Glass <sjg@chromium.org>
Suggested-by: Tom Rini <trini@konsulko.com>

1 files changed, 16 insertions, 5 deletions

diff --git a/tools/buildman/README b/tools/buildman/README
index c67a074cb50..0666bc7d564 100644
--- a/tools/buildman/README
+++ b/tools/buildman/README
@@ -128,10 +128,10 @@ Selecting which boards to build
 ===============================
 
 Buildman lets you build all boards, or a subset. Specify the subset by passing
-command-line arguments that list the desired board name, architecture name,
-SOC name, or anything else in the boards.cfg file. Multiple arguments are
-allowed. Each argument will be interpreted as a regular expression, so
-behaviour is a superset of exact or substring matching. Examples are:
+command-line arguments that list the desired build target, architecture,
+CPU, board name, vendor, SoC or options. Multiple arguments are allowed. Each
+argument will be interpreted as a regular expression, so behaviour is a superset
+of exact or substring matching. Examples are:
 
 * 'tegra20'      All boards with a Tegra20 SoC
 * 'tegra'        All boards with any Tegra Soc (Tegra20, Tegra30, Tegra114...)
@@ -1054,7 +1054,6 @@ between one commit and the next.
 For example:
 
 $ buildman -b squash brppt1 -sU
-boards.cfg is up to date. Nothing to do.
 Summary of 2 commits for 3 boards (3 threads, 3 jobs per thread)
 01: Migrate bootlimit to Kconfig
 02: Squashed commit of the following:
@@ -1309,6 +1308,18 @@ Some options you might like are:
         break anything. But note this does not check bisectability!
 
 
+Using boards.cfg
+================
+
+This file is no-longer needed by buildman but it is still generated in the
+working directory. This helps avoid a delay on every build, since scanning all
+the Kconfig files takes a few seconds. Use the -R flag to force regeneration
+of the file - in that case buildman exits after writing the file.
+
+You should use 'buildman -nv <criteria>' instead of greoing the boards.cfg file,
+since it may be dropped altogether in future.
+
+
 TODO
 ====