LaunchXL-TMS57004: Switch to use big-endian, Cortex-R4 buildroot toolchain

configs/launchxl-tms57004/README.txt

@@ -8,23 +8,61 @@ README
 Contents
 ========
 
+  - Status
   - Toolchain
   - LEDs and Buttons
   - Serial Console
   - Debugging
   - Configurations
 
+Status
+======
+
+  The basic port to the TMS570 is complete.  Testing is, however, stalled.
+  The TMD570 hardware is big-endian and I have not yet found an ARM toolchain
+  that will support big-endian operation.
+
 Toolchain
 =========
 
+  Build Platform
+  --------------
   All of these configurations are set up to build with Cygwin under Windows
-  using the "GNU Tools for ARM Embedded Processors" that is maintained by ARM
   (unless stated otherwise in the description of the configuration).
 
+  Endian-ness Issues
+  ------------------
+  I started using the the "GNU Tools for ARM Embedded Processors" that is
+  maintained by ARM.
+
     https://launchpad.net/gcc-arm-embedded
 
-  That toolchain selection can easily be reconfigured using 'make menuconfig'.
-  Here are the relevant current settings:
+  However, that tool chain will not support the TMS570 big-endian mode.
+  Certainly the -mbig-endian options will compiler for big-endian, but the
+  final link fails because there is no big-endian version lib libgcc.
+
+  There are patches available here if you want to build that toolchain
+  from scratch:
+
+    https://launchpad.net/gcc-arm-embedded/+question/27995
+
+  I now use a version of the NuttX buildroot toolchain that can be built like
+  this:
+
+    cd buildroot/
+    cp configs/cortexr4-armeb-eabi-4.8.3-defconfig .config
+    make oldconfig
+    make
+
+  You have to have several obscure packages installed on your Linux or Cygwin
+  system to build the toolchain like this:  GMP, MPFR, MPC, and probably
+  others.  See the buildroot/README.txt file for additional important information
+  about building the toolchain.
+
+  Reconfiguring
+  -------------
+  The build configuration selections can easily be reconfigured using 'make
+  menuconfig'.  Here are the relevant current settings:
 
      Build Setup:
        CONFIG_HOST_WINDOWS=y               : Window environment

configs/launchxl-tms57004/nsh/Make.defs

@@ -107,8 +107,11 @@ LIBEXT = .a
 EXEEXT =
 
 ifneq ($(CROSSDEV),arm-nuttx-elf-)
+ifneq ($(CROSSDEV),armeb-nuttx-elf-)
   LDFLAGS += -nostartfiles -nodefaultlibs
 endif
+endif
+
 ifeq ($(CONFIG_DEBUG_SYMBOLS),y)
   LDFLAGS += -g
 endif

configs/launchxl-tms57004/nsh/defconfig

@@ -130,12 +130,13 @@ CONFIG_ARCH_LOWVECTORS=y
 CONFIG_ARMV7R_MEMINIT=y
 # CONFIG_ARMV7R_HAVE_L2CC is not set
 # CONFIG_ARMV7R_HAVE_L2CC_PL310 is not set
-# CONFIG_ARMV7R_TOOLCHAIN_BUILDROOT is not set
+CONFIG_ARMV7R_TOOLCHAIN_BUILDROOT=y
 # CONFIG_ARMV7R_TOOLCHAIN_CODESOURCERYW is not set
 # CONFIG_ARMV7R_TOOLCHAIN_DEVKITARM is not set
 # CONFIG_ARMV7R_TOOLCHAIN_GNU_EABIL is not set
-CONFIG_ARMV7R_TOOLCHAIN_GNU_EABIW=y
+# CONFIG_ARMV7R_TOOLCHAIN_GNU_EABIW is not set
 # CONFIG_ARMV7R_TOOLCHAIN_GNU_OABI is not set
+# CONFIG_ARMV7R_OABI_TOOLCHAIN is not set
 CONFIG_ARMV7R_HAVE_DECODEFIQ=y
 # CONFIG_ARMV7R_DECODEFIQ is not set
 # CONFIG_SERIAL_TERMIOS is not set

configs/launchxl-tms57004/nsh/setenv.sh

@@ -61,7 +61,7 @@ fi
 
 # This is the location where I installed the ARM "GNU Tools for ARM Embedded Processors"
 # You can this free toolchain here https://launchpad.net/gcc-arm-embedded
-export TOOLCHAIN_BIN="/cygdrive/c/Program Files (x86)/GNU Tools ARM Embedded/4.9 2015q2/bin"
+# export TOOLCHAIN_BIN="/cygdrive/c/Program Files (x86)/GNU Tools ARM Embedded/4.9 2015q2/bin"
 
 # This is the path to the location where I installed the devkitARM toolchain
 # You can get this free toolchain from http://devkitpro.org/ or http://sourceforge.net/projects/devkitpro/
@@ -69,7 +69,7 @@ export TOOLCHAIN_BIN="/cygdrive/c/Program Files (x86)/GNU Tools ARM Embedded/4.9
 
 # This is the Cygwin path to the location where I build the buildroot
 # toolchain.
-# export TOOLCHAIN_BIN="${WD}/../buildroot/build_arm_nofpu/staging_dir/bin"
+export TOOLCHAIN_BIN="${WD}/../buildroot/build_armeb/staging_dir/bin"
 
 # Add the path to the toolchain to the PATH varialble
 export PATH="${TOOLCHAIN_BIN}:/sbin:/usr/sbin:${PATH_ORIG}"