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+#
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+# (C) Copyright 2014 Google, Inc
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+# Simon Glass <sjg@chromium.org>
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+#
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+# SPDX-License-Identifier: GPL-2.0+
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+#
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+
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+DEPRECATION NOTICE FOR arch/<arch>/lib/board.c
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+
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+For board maintainers: Please submit patches for boards you maintain before
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+July 2014, to make them use generic board.
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+
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+For architecture maintainers: Please submit patches to remove your
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+architecture-specific board.c file before October 2014.
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+
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+
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+Background
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+----------
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+
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+U-Boot has tranditionally had a board.c file for each architecture. This has
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+introduced quite a lot of duplication, with each architecture tending to do
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+initialisation slightly differently. To address this, a new 'generic board
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+init' feature was introduced a year ago in March 2013 (further motivation is
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+provided in the cover letter below).
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+
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+
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+What has changed?
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+-----------------
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+
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+The main change is that the arch/<arch>/lib/board.c file is being removed in
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+favour of common/board_f.c (for pre-relocation init) and common/board_r.c
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+(for post-relocation init).
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+
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+Related to this, the global_data and bd_t structures now have a core set of
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+fields which are common to all architectures. Architecture-specific fields
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+have been moved to separate structures.
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+
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+
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+Supported Arcthitectures
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+------------------------
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+
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+If you are unlucky then your architecture may not support generic board.
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+The following architectures are supported at the time of writing:
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+
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+ arc
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+ arm
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+ powerpc
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+ sandbox
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+ x86
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+
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+If your architecture is not supported, you need to adjust your
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+arch/<arch>/config.mk file to include:
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+
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+ __HAVE_ARCH_GENERIC_BOARD := y
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+
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+and test it with a suitable board, as follows.
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+
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+
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+Adding Support for your Board
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+-----------------------------
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+
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+To enable generic board for your board, define CONFIG_SYS_GENERIC_BOARD in
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+your board config header file.
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+
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+Test that U-Boot still functions correctly on your board, and fix any
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+problems you find. Don't be surprised if there are no problems - generic
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+board has had a reasonable amount of testing with common boards.
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+
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+
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+DeadLine
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+--------
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+
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+Please don't take this the wrong way - there is no intent to make your life
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+miserable, and we have the greatest respect and admiration for U-Boot users.
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+However, with any migration there has to be a period where the old way is
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+deprecated and removed. Every patch to the deprecated code introduces a
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+potential breakage in the new unused code. Therefore:
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+
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+Boards or architectures not converted over to general board by the
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+end of 2014 may be forcibly changed over (potentially causing run-time
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+breakage) or removed.
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+
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+
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+
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+Further Background
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+------------------
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+
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+The full text of the original generic board series is reproduced below.
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+
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+--8<-------------
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+
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+This series creates a generic board.c implementation which contains
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+the essential functions of the major arch/xxx/lib/board.c files.
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+
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+What is the motivation for this change?
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+
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+1. There is a lot of repeated code in the board.c files. Any change to
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+things like setting up the baud rate requires a change in 10 separate
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+places.
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+
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+2. Since there are 10 separate files, adding a new feature which requires
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+initialisation is painful since it must be independently added in 10
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+places.
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+
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+3. As time goes by the architectures naturely diverge since there is limited
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+pressure to compare features or even CONFIG options against simiilar things
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+in other board.c files.
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+
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+4. New architectures must implement all the features all over again, and
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+sometimes in subtley different ways. This places an unfair burden on getting
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+a new architecture fully functional and running with U-Boot.
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+
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+5. While it is a bit of a tricky change, I believe it is worthwhile and
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+achievable. There is no requirement that all code be common, only that
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+the code that is common should be located in common/board.c rather than
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+arch/xxx/lib/board.c.
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+
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+All the functions of board_init_f() and board_init_r() are broken into
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+separate function calls so that they can easily be included or excluded
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+for a particular architecture. It also makes it easier to adopt Graeme's
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+initcall proposal when it is ready.
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+
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+http://lists.denx.de/pipermail/u-boot/2012-January/114499.html
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+
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+This series removes the dependency on generic relocation. So relocation
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+happens as one big chunk and is still completely arch-specific. See the
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+relocation series for a proposed solution to this for ARM:
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+
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+http://lists.denx.de/pipermail/u-boot/2011-December/112928.html
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+
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+or Graeme's recent x86 series v2:
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+
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+http://lists.denx.de/pipermail/u-boot/2012-January/114467.html
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+
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+Instead of moving over a whole architecture, this series takes the approach
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+of simply enabling generic board support for an architecture. It is then up
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+to each board to opt in by defining CONFIG_SYS_GENERIC_BOARD in the board
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+config file. If this is not done, then the code will be generated as
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+before. This allows both sets of code to co-exist until we are comfortable
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+with the generic approach, and enough boards run.
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+
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+ARM is a relatively large board.c file and one which I can test, therefore
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+I think it is a good target for this series. On the other hand, x86 is
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+relatively small and simple, but different enough that it introduces a
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+few issues to be solved. So I have chosen both ARM and x86 for this series.
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+After a suggestion from Wolfgang I have added PPC also. This is the
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+largest and most feature-full board, so hopefully we have all bases
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+covered in this RFC.
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+
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+A generic global_data structure is also required. This might upset a few
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+people. Here is my basic reasoning: most fields are the same, all
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+architectures include and need it, most global_data.h files already have
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+#ifdefs to select fields for a particular SOC, so it is hard to
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+see why architecures are different in this area. We can perhaps add a
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+way to put architecture-specific fields into a separate header file, but
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+for now I have judged that to be counter-productive.
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+
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+Similarly we need a generic bd_info structure, since generic code will
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+be accessing it. I have done this in the same way as global_data and the
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+same comments apply.
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+
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+There was dicussion on the list about passing gd_t around as a parameter
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+to pre-relocation init functions. I think this makes sense, but it can
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+be done as a separate change, and this series does not require it.
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+
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+While this series needs to stand on its own (as with the link script
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+cleanup series and the generic relocation series) the goal is the
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+unification of the board init code. So I hope we can address issues with
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+this in mind, rather than focusing too narrowly on particular ARM, x86 or
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+PPC issues.
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+
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+I have run-tested ARM on Tegra Seaboard only. To try it out, define
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+CONFIG_SYS_GENERIC_BOARD in your board file and rebuild. Most likely on
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+x86 and PPC at least it will hang, but if you are lucky it will print
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+something first :-)
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+
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+I have run this though MAKEALL with CONFIG_SYS_GENERIC_BOARD on for all
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+ARM, PPC and x86 boards. There are a few failures due to errors in
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+the board config, which I have sent patches for. The main issue is
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+just the difference between __bss_end and __bss_end__.
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+
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+Note: the first group of commits are required for this series to build,
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+but could be separated out if required. I have included them here for
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+convenience.
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+
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+------------->8--
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+
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+Simon Glass, sjg@chromium.org
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+March 2014
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