Baremetal Raspberry PI build support (nesbox#918)

* Raspberry PI baremetal support

* boot utils for baremetal RPI

* Building instructions

* fix surf continuously accessing disk

.gitignore

@@ -130,6 +130,8 @@ lib/
 *.cmake
 CMakeCache.txt
 Makefile
+!build/baremetalpi/Makefile
+!build/baremetalpi/boot/Makefile
 build/android/.gradle/
 build/android/app/.externalNativeBuild/
 build/android/app/build/

CMakeLists.txt

@@ -3,6 +3,8 @@ cmake_minimum_required(VERSION 3.3)
 project(TIC-80 C CXX)
 message("Building for target : ${CMAKE_SYSTEM_NAME}")
 
+
+
 if(ANDROID OR EMSCRIPTEN)
 	set(BUILD_SOKOL_DEFAULT OFF)
 	set(BUILD_LIBRETRO_DEFAULT OFF)
@@ -19,6 +21,59 @@ option(BUILD_LIBRETRO "libretro Enabled" ${BUILD_LIBRETRO_DEFAULT})
 option(BUILD_DEMO_CARTS "Demo Carts Enabled" ${BUILD_DEMO_CARTS_DEFAULT})
 option(BUILD_PRO "Build PRO version" FALSE)
 
+if (BAREMETALPI)
+
+set(BUILD_SDL off)
+set(BUILD_DEMO_CARTS OFF)
+
+set(CMAKE_SYSTEM_NAME Generic)
+set(CMAKE_SYSTEM_PROCESSOR ARM)
+
+if(MINGW OR CYGWIN OR WIN32)
+    set(UTIL_SEARCH_CMD where)
+elseif(UNIX OR APPLE)
+    set(UTIL_SEARCH_CMD which)
+endif()
+
+set(TOOLCHAIN_PREFIX arm-none-eabi-)
+
+execute_process(
+  COMMAND ${UTIL_SEARCH_CMD} ${TOOLCHAIN_PREFIX}gcc
+  OUTPUT_VARIABLE BINUTILS_PATH
+  OUTPUT_STRIP_TRAILING_WHITESPACE
+)
+message("Crosscompiler path is ${BINUTILS_PATH}")
+get_filename_component(ARM_TOOLCHAIN_DIR ${BINUTILS_PATH} DIRECTORY)
+
+# Without that flag CMake is not able to pass test compilation check
+if (${CMAKE_VERSION} VERSION_EQUAL "3.6.0" OR ${CMAKE_VERSION} VERSION_GREATER "3.6")
+    set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
+else()
+    set(CMAKE_EXE_LINKER_FLAGS_INIT "-Wl,-E")
+endif()
+
+# removed squirrel language as it doesn't seem to compile under arm. Needs investigation.
+# note: hardcoded flags are for RPI2. Should try to use the ones
+# generated in CIRCLE during config
+set(CMAKE_C_FLAGS " -DTIC_BUILD_WITH_FENNEL -DTIC_BUILD_WITH_MOON -DTIC_BUILD_WITH_JS -DTIC_BUILD_WITH_WREN -DTIC_BUILD_WITH_LUA -DLUA_32BITS -std=c99 -march=armv7-a+neon-vfpv4  -D AARCH=32 -D __circle__ -D BAREMETALPI  --specs=nosys.specs -O3 -mabi=aapcs -marm  -mfloat-abi=hard -mfpu=neon-vfpv4  -D__DYNAMIC_REENT__")
+
+set(CMAKE_C_COMPILER ${TOOLCHAIN_PREFIX}gcc)
+set(CMAKE_ASM_COMPILER ${CMAKE_C_COMPILER})
+set(CMAKE_CXX_COMPILER ${TOOLCHAIN_PREFIX}g++)
+
+set(CMAKE_OBJCOPY ${ARM_TOOLCHAIN_DIR}/${TOOLCHAIN_PREFIX}objcopy CACHE INTERNAL "objcopy tool")
+set(CMAKE_SIZE_UTIL ${ARM_TOOLCHAIN_DIR}/${TOOLCHAIN_PREFIX}size CACHE INTERNAL "size tool")
+
+set(CMAKE_SYSROOT ${ARM_TOOLCHAIN_DIR}/../arm-none-eabi)
+set(CMAKE_FIND_ROOT_PATH ${BINUTILS_PATH})
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+
+endif()
+
+
+
 if(UNIX AND NOT APPLE AND NOT EMSCRIPTEN AND NOT ANDROID)
 	set(LINUX TRUE)
 endif()

build/baremetalpi/Makefile

@@ -0,0 +1,47 @@
+#
+# Makefile
+#
+TIC80HOME = ../..
+TIC803RD = $(TIC80HOME)/3rd-party
+CIRCLESTDLIB = $(TIC803RD)/circle-stdlib/
+CIRCLEHOME = $(CIRCLESTDLIB)/libs/circle
+NEWLIBDIR = $(CIRCLESTDLIB)/install/arm-none-circle
+TIC80LIB = $(TIC80HOME)/build/lib
+TIC80SRC = $(TIC80HOME)/src
+BAREMETALSYSTEM = $(TIC80SRC)/system/baremetalpi
+
+OBJS	= \
+	$(BAREMETALSYSTEM)/main.o $(BAREMETALSYSTEM)/kernel.o $(BAREMETALSYSTEM)/customchargenerator.o \
+	$(BAREMETALSYSTEM)/customscreen.o $(BAREMETALSYSTEM)/utils.o $(BAREMETALSYSTEM)/gamepads.o
+
+include $(CIRCLEHOME)/Rules.mk
+
+CFLAGS += -I "$(NEWLIBDIR)/include" -I $(STDDEF_INCPATH) -I $(CIRCLESTDLIB)/include -I $(TIC80HOME)/include -I $(TIC80SRC) \
+	  -D BAREMETALPI
+
+
+LIBS :=  \
+	$(TIC80LIB)/libtic80lib.a \
+	$(TIC80LIB)/libtic80core.a \
+	$(TIC80LIB)/libgiflib.a \
+	$(TIC80LIB)/liblpeg.a \
+ 	$(TIC80LIB)/liblua.a \
+	$(TIC80LIB)/libwren.a \
+	$(TIC80LIB)/libzlib.a \
+	$(NEWLIBDIR)/lib/libc.a \
+        $(NEWLIBDIR)/lib/libcirclenewlib.a \
+	$(CIRCLEHOME)/addon/vc4/sound/libvchiqsound.a \
+        $(CIRCLEHOME)/addon/vc4/vchiq/libvchiq.a \
+        $(CIRCLEHOME)/addon/linux/liblinuxemu.a \
+ 	$(CIRCLEHOME)/addon/SDCard/libsdcard.a \
+ 	$(CIRCLEHOME)/addon/fatfs/libfatfs.a \
+  	$(CIRCLEHOME)/lib/usb/libusb.a \
+ 	$(CIRCLEHOME)/lib/input/libinput.a \
+ 	$(CIRCLEHOME)/lib/fs/fat/libfatfs.a \
+ 	$(CIRCLEHOME)/lib/fs/libfs.a \
+  	$(CIRCLEHOME)/lib/net/libnet.a \
+  	$(CIRCLEHOME)/lib/sched/libsched.a \
+  	$(CIRCLEHOME)/lib/libcircle.a \
+	$(NEWLIBDIR)/lib/libm.a
+
+#	$(TIC80LIB)/libsquirrel.a \

build/baremetalpi/README.md

@@ -0,0 +1,93 @@
+
+# Raspberry PI Baremetal build
+
+The following explains how to build TIC-80 for the Raspberry PI boards in baremetal mode, that is, without an operating system (the board boots directly in TIC-80)
+
+# Requirements
+
+You need:
+
+- A Linux machine
+- gcc ARM toolchain. You can get it [here](https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-rm/downloads). Successfully tested with version: gcc-arm-none-eabi-8-2018-q4-major
+- A standard building environment (make, cmake, gcc, wget, etc)
+
+# Building instructions
+
+Following are all the building steps for building the system.
+
+First, set the path to include the arm toolkit (fix the command with your path):
+
+```
+PATH=/home/you/gcc-arm-none-eabi-8-2018-q4-major/bin/:$PATH
+```
+
+Get a fresh copy of TIC-80 repository and build demo carts:
+
+```
+git clone --recursive https://github.com/nesbox/TIC-80
+cd TIC-80
+sh build_demos.sh
+```
+
+Clone and build circle/circle-stdlib:
+
+```
+cd 3rd-party
+git clone --recursive https://github.com/smuehlst/circle-stdlib.git
+cd circle-stdlib
+./configure -r 2
+make
+```
+
+Make some addon that are not compiled automatically:
+
+```
+cd libs/circle/addon/vc4/sound/
+make
+cd ../vchiq
+make
+cd ../../linux
+make
+cd ../fatfs
+make
+cd ../../../../../..
+```
+
+Build `tic80lib` for arm with baremetal customizations:
+
+```
+cd build
+cmake -DCMAKE_BUILD_TYPE=MinSizeRel -DBAREMETALPI=1 ..
+make tic80lib
+```
+
+Build the kernel:
+
+```
+cd baremetalpi
+make
+```
+
+This generates the final `kernel7.img` file. Copy it into your SD card root.
+
+Now you have to prepare some bootup files that need to be copied to the SD card root together with your kernel7.img. This only need to be done once:
+
+```
+cd boot
+make
+```
+
+Now copy the following files to your SD card
+
+- `config.txt`
+- `LICENCE.broadcom`
+- `bootcode.bin`
+- `fixup.dat`
+- `start.elf`
+
+You need to create a `tic80` folder into your SD card. Your carts go in there.
+
+# Thanks
+
+This project is built on two awesome projects, [circle](https://github.com/rsta2/circle) and [circle-stdlib](https://github.com/smuehlst/circle-stdlib). Without them, this version of TIC-80 would not exists.
+

build/baremetalpi/boot/Makefile

@@ -0,0 +1,14 @@
+#
+# Download the firmware files to be required for boot (requires wget)
+#
+# These files must be copied along with the generated kernel.img
+#     onto a SD(HC) card with FAT file system.
+#
+
+firmware:
+	wget -q -O LICENCE.broadcom https://github.com/raspberrypi/firmware/blob/master/boot/LICENCE.broadcom?raw=true
+	wget -q -O bootcode.bin https://github.com/raspberrypi/firmware/blob/master/boot/bootcode.bin?raw=true
+	wget -q -O fixup.dat https://github.com/raspberrypi/firmware/blob/master/boot/fixup.dat?raw=true
+	wget -q -O start.elf https://github.com/raspberrypi/firmware/blob/master/boot/start.elf?raw=true
+
+all: firmware

build/baremetalpi/boot/config.txt

@@ -0,0 +1,3 @@
+hdmi_group=1
+hdmi_mode=16
+scaling_kernel=8

include/tic80_types.h

@@ -27,10 +27,18 @@
 
 typedef uint8_t u8;
 typedef uint16_t u16;
+#if defined(BAREMETALPI)
+typedef unsigned int u32;
+#else
 typedef uint32_t u32;
+#endif
 typedef uint64_t u64;
 
 typedef int8_t s8;
 typedef int16_t s16;
+#if defined(BAREMETALPI)
+typedef signed int s32; // TODO understand why it breaks
+#else
 typedef int32_t s32;
+#endif
 typedef int64_t s64;