The current mechanism uses a completely separate build rule for each
file which must be built with system headers. This is tricky to
maintain.

Add a foreach template in the sandbox cpu Makefile which generates the
custom compile rules from a CFLAGS_USE_SYSHDRS list. This keeps the
rules data-driven without needing changes to the common
scripts/Makefile.lib, which could affect other architectures.

Move initjmp.o into the template since it uses the same pattern. Add
sdl.o to the list too, with an override for its command since it also
needs -fshort-wchar removed and -fno-lto added.

Signed-off-by: Simon Glass <sjg@chromium.org>

Add initjm[() to sandbox, a non-standard extension to setjmp()/
longjmp() allowing to initialize a jump buffer with a function pointer
and a stack pointer. This will be useful to later introduce threads.
With this new function it becomes possible to longjmp() to a particular
function pointer (rather than to a point previously reached during
program execution as is the case with setjmp()), and with a custom stack.
Both things are needed to spin off a new thread. Then the usual
setjmp()/longjmp() pair is enough to save and restore a context, i.e.,
switch thread. The implementation is taken verbatim from barebox [1] with
the exception of the additional stack_sz argument. It is quite complex
because contrary to U-Boot platform code we don't know how the system's
C library implements the jump buffer, so we can't just write the function
and stack pointers into it.

[1] https://github.com/barebox/barebox/blob/b2a15c383ddc/arch/sandbox/os/setjmp.c

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>

Use the new symbol to refer to any 'SPL' build, including TPL and VPL

Signed-off-by: Simon Glass <sjg@chromium.org>

sdl.c is compiled against the SDL library.

Trying to redefine wchar_t with -fshort-wchar is not necessary
and leads to build failures when compiling against musl.

Cc: Milan P. Stanić <mps@arvanta.net>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Before executing code that we have loaded from a file we need to flush the
data cache and invalidate the instruction flash.

Implement functions flush_cache() and invalidate_icache_all().

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

At present sandbox has a start.o in the 'start' target but also includes
it in the normal target list. This is not how this is normally handled. It
is needed because sandbox does not include the u-boot-init variable in its
link rule.

Update the rule and move start.o from the normal target list to the
'extras' list.

Signed-off-by: Simon Glass <sjg@chromium.org>

When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>

Add an sandbox implementation for the generic SPL framework. This supports
locating and running U-Boot proper.

Signed-off-by: Simon Glass <sjg@chromium.org>

Implement a bridge between U-Boot's network stack and Linux's raw packet
API allowing the sandbox to send and receive packets using the host
machine's network interface.

This raw Ethernet API requires elevated privileges.  You can either run
as root, or you can add the capability needed like so:

sudo /sbin/setcap "CAP_NET_RAW+ep" /path/to/u-boot

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

SDL (Simple DirectMedia Layer - see www.libsdl.org) is a library which
provides simple graphics and sound features. It works under X11 and also
with a simple frame buffer interface. It is ideally suited to sandbox
U-Boot since it fits nicely with the low-level feature set required by
U-Boot. For example, U-Boot has its own font drawing routines, its own
keyboard processing and just needs raw sound output.

We can use SDL to provide emulation of these basic functions for sandbox.
This significantly expands the testing that is possible with sandbox.

Add a basic SDL library which we will use in future commits.

Tested-by: Che-Liang Chiou <clchiou@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>