kvx: remove duplicated dtb symbols ...

dtb symbols (__dtb_start, __dtb_end) are already defined using
RO_DATA_SECTION. This duplicated dtb section is a leftover used by
Kalray internal tools to patch the dtb when loading the elf on a
target. Remove it to keep only one symbol definition.

Signed-off-by: Clement Leger <cleger@kalray.eu>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

kvx: add support for elf loading using bootm ...

In order to boot elfs files, add bootm command support for kvx. This support
can boot elf files using bootm elf support. initrd and device-tree handling
is also included and loads them after the elf file load address.

Signed-off-by: Clement Leger <cleger@kalray.eu>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

kvx: add I-cache and D-cache synchronisation ...

Before booting, we must make sure the I-cache is synchronized with the
D-cache to execute loaded instructions. In order to do that, add a
function which execute a fence to ensure every memory accesses have
been committed out of processor pipeline to memory and then invalidate
I-cache to reload from memory.

Signed-off-by: Clement Leger <cleger@kalray.eu>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

kbuild: fix typo in --no-whole-archive flag ...

"whole" was replaced with "while" during a previous patch. Fix this flag
to allow building correctly.

Fixes 0a78b33954 ("kbuild: switch over to thin archive")
Signed-off-by: Clement Leger <cleger@kalray.eu>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Merge branch 'for-next/kvx'

kbuild: switch over to thin archive ...

Starting v4.13, Linux always uses thin archive instead of relocatable
ELF to combine builtin objects.

The thin archive is basically a text file that only contains paths to
object files.

As Linux commit 98ced886dd79 mentioned, this has a lot of benefits:

 - save disk space for builds

 - speed-up building a little

 - fix some issues when liking a giant executable (for example,
   allyesconfig on ARM Linux)

 - work better with dead code elimination

The last one is important for barebox because pbl highly relies on the
dead code elimination (-f{function,data}-sections and --gc-sections)
dropping symbols that are unreachable from the linker's entry point.
The dead code elimination does not work if the same symbol names are
used in the pevious incremental link mechanism because the same name
symbols all go into the same section.

Commit a83c97f2a406 ("ARM: socfpga: generate smaller images when
multiple boards are selected") worked around it by giving a dedicate
section to each of the same name symbols. This workaround can go away.

built-in.o was renamed to built-in.a since it is now an archive.
built-in-pbl.o was renamed to built-in.pbl.a for consistency.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

kbuild: remove obj-dtb-y, pbl-dtb-y, lwl-dtb-y syntax ...

The embedded DTBs are compiled by the chain of pattern rules as follows:

  %.dts -> %.dtb -> %.dtb.S -> %.dtb.o       for barebox proper
  %.dts -> %.dtb -> %.dtb.S -> %.dtb.pbl.o   for pbl

Barebox introduced {obj,pbl,lwl}-dtb-y syntax to put the intermediate
files into extra-y. The purposes of doing so were:

 [1] prevent GNU Make from deleting the intermediate files
 [2] include .*.cmd files

In contrast, Linux does not use a special syntax for embedding DTBs
into the kernel.

For example, as you see in arch/sh/boot/dts/Makefile of Linux 5.6,

   obj-y += <basename>.dtb.o

... just works.

This is because scripts/Kbuild.include specifies .SECONDARY to cater
to [1], and scripts/Makefile.build adds the intermediates to 'targets'
to deal with [2].

Barebox had already imported the same code from Linux, so you can use
obj-y instead of obj-dtb-y, like Linux.

pbl-dtb-y and lwl-dtb-y are barebox-specific cases, so I added the
%.dtb.pbl.o pattern to intermediate_targets.

Going forward, please use obj-y, pbl-y, or lwl-y.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

kvx: do not include empty <config.h> ...

<config.h> is per-board config file, which is only allowed for old
boards.

For new boards, the top Makefile creates an empty include/config.h

kvx does not have config.h, so #include <config.h> is useless.

Also, remove meaningless board-$(CONFIG_GENERIC).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-By: Clement Leger <cleger@kalray.eu>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

kbuild: prefix compiler flag variables with KBUILD_ ...

In old days, Linux also used to use well-known variables such CFLAGS,
CPPFLAGS, etc.

They were prefixed with KBUILD_ presumably for preventing users from
overriding them accidentally.

Rename as follows:
  CFLAGS          ->  KBUILD_CFLAGS
  AFLAGS          ->  KBUILD_AFLAGS
  CPPFLAGS        ->  KBUILD_CPPFLAGS
  LDFLAGS         ->  KBUILD_LDFLAGS
  HOSTCFLAGS      ->  KBUILD_HOSTCFLAGS
  HOSTCXXFLAGS    ->  KBUILD_HOSTCXXFLAGS
  HOSTLDFLAGS     ->  KBUILD_HOSTLDFLAGS
  HOST_LOADLIBES  ->  KBUILD_HOSTLDLIBS

HOSTCFLAGS, HOSTCXXFLAGS, HOSTLDFLAGS, HOSTLDLIBS are re-used to allow
users to pass-in additional flags to the host compiler.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

watchdog: kvx: Add kvx watchdog support ...

Add a watchdog for kvx architecture based on core watchdog.

Signed-off-by: Clement Leger <cleger@kalray.eu>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clocksource: kvx: Add kvx clocksource support ...

Add a clocksource for kvx architecture based on core performance
counter. This performance counter is configured to count cycles and as
such can be used to be a clocksource.

Signed-off-by: Clement Leger <cleger@kalray.eu>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

kvx: Implement reset source and reset ...

Implement reset and reset source handling using ftu. This support uses
regmap to access the ftu easily using "kalray,kvx-syscon" compatible.

Signed-off-by: Clement Leger <cleger@kalray.eu>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

kvx: Add support for device tree ...

Add dts folder with minimal device tree for kalray K200 board.

Signed-off-by: Clement Leger <cleger@kalray.eu>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

kvx: Add processor definitions ...

This file is generated from processor description and is used to access
and modify processor registers.

Signed-off-by: Clement Leger <cleger@kalray.eu>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

kvx: Initial Kalray Coolidge (kv3) architecture support ...

Add kalray coolidge arch/ support.

Signed-off-by: Clement Leger <cleger@kalray.eu>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>