sandbox: Add SDL library for LCD, keyboard, audio

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>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/sandbox/cpu/Makefile b/arch/sandbox/cpu/Makefile
index 63deded..7d4410c 100644
--- a/arch/sandbox/cpu/Makefile
+++ b/arch/sandbox/cpu/Makefile
@@ -8,6 +8,7 @@
 #
 
 obj-y	:= cpu.o os.o start.o state.o
+obj-$(CONFIG_SANDBOX_SDL)	+= sdl.o
 
 # os.c is build in the system environment, so needs standard includes
 # CFLAGS_REMOVE_os.o cannot be used to drop header include path
@@ -17,3 +18,5 @@ cmd_cc_os.o = $(CC) $(filter-out -nostdinc, \
 
 $(obj)/os.o: $(src)/os.c FORCE
 	$(call if_changed_dep,cc_os.o)
+$(obj)/sdl.o: $(src)/sdl.c FORCE
+	$(call if_changed_dep,cc_os.o)