[PATCH v2 4/9] rockchip: rk3399: Get bl31.elf via BL31

[Jagan Teki <jagan-dyjBcgdgk7Pe9wHmmfpqLFaTQe2KTcn/@public.gmane.org>]

Right now rockchip platform need to copy bl31.elf into u-boot
source directory to make use of building u-boot.itb.

So, add environment variable BL31 like Allwinner SoC so-that the
bl31.elf would available via BL31.

If the builds are not exporting BL31 env, the make_fit_atf.py
explicitly create dummy bl31.elf in u-boot root directory to
satisfy travis builds and it will show the warning on console as

 WARNING: BL31 file bl31.elf NOT found, resulting binary is non-functional
 WARNING: Please read Building section in doc/README.rockchip

Note, that the dummy bl31 files were created during not exporting
BL31 case would be removed via clean target in Makefile.

Cc: Emmanuel Vadot <manu-xXdDKFdH5B3kFDPD4ZthVA@public.gmane.org> <manu-h+KGxgPPiopAfugRpC6u6w@public.gmane.org>
Signed-off-by: Jagan Teki <jagan-dyjBcgdgk7Pe9wHmmfpqLFaTQe2KTcn/@public.gmane.org>
---
 Makefile                               |  2 +-
 arch/arm/mach-rockchip/make_fit_atf.py | 11 ++++++++++-
 doc/README.rockchip                    |  4 ++--
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index ba0cce9f33..2471340c71 100644
--- a/Makefile
+++ b/Makefile
@@ -1782,7 +1782,7 @@ clean: $(clean-dirs)
 		-o -name 'dsdt.aml' -o -name 'dsdt.asl.tmp' -o -name 'dsdt.c' \
 		-o -name '*.efi' -o -name '*.gcno' -o -name '*.so' \) \
 		-type f -print | xargs rm -f \
-		bl31_*.bin image.map
+		bl31.c bl31.elf bl31_*.bin image.map
 
 # mrproper - Delete all generated files, including .config
 #
diff --git a/arch/arm/mach-rockchip/make_fit_atf.py b/arch/arm/mach-rockchip/make_fit_atf.py
index d1faff1957..327875d87b 100755
--- a/arch/arm/mach-rockchip/make_fit_atf.py
+++ b/arch/arm/mach-rockchip/make_fit_atf.py
@@ -10,6 +10,7 @@ usage: $0 <dt_name> [<dt_name> [<dt_name] ...]
 import os
 import sys
 import getopt
+import logging
 
 # pip install pyelftools
 from elftools.elf.elffile import ELFFile
@@ -194,8 +195,16 @@ def get_bl31_segments_info(bl31_file_name):
 
 def main():
     uboot_elf="./u-boot"
-    bl31_elf="./bl31.elf"
     FIT_ITS=sys.stdout
+    if "BL31" in os.environ:
+        bl31_elf=os.getenv("BL31");
+    else:
+        os.system("echo 'int main(){}' > bl31.c")
+        os.system("${CROSS_COMPILE}gcc -c bl31.c -o bl31.elf")
+        bl31_elf="./bl31.elf"
+        logging.basicConfig(format='%(levelname)s:%(message)s', level=logging.DEBUG)
+        logging.warning(' BL31 file bl31.elf NOT found, resulting binary is non-functional')
+        logging.warning(' Please read Building section in doc/README.rockchip')
 
     opts, args = getopt.getopt(sys.argv[1:], "o:u:b:h")
     for opt, val in opts:
diff --git a/doc/README.rockchip b/doc/README.rockchip
index ca4d6473b0..98a3824e2c 100644
--- a/doc/README.rockchip
+++ b/doc/README.rockchip
@@ -149,8 +149,8 @@ For example:
 	=> make realclean
 	=> make CROSS_COMPILE=aarch64-linux-gnu- PLAT=rk3399
 
-	(copy bl31.elf into U-Boot root dir)
-	=> cp build/rk3399/release/bl31/bl31.elf /path/to/u-boot
+	(export bl31.elf)
+	=> export BL31=/path/to/arm-trusted-firmware/build/rk3399/release/bl31/bl31.elf
 
    - Compile PMU M0 firmware
 
-- 
2.18.0.321.gffc6fa0e3