Allow booting in DSi direct mode without BIOS/firmware/NAND dumps. (#2523)

* Allow booting in DSi direct mode without BIOS/firmware/NAND dumps.

This is an initial patch which enables booting programs in DSi direct mode
without requiring BIOS/firmware/NAND dumps from increasingly expensive
consoles:

- The open DSi BIOS is derived from a modified build of FreeBIOS; minor patches
  have been done (such as moving SWI 0x12 to 0x02), but no new SWI functions
  have been implemented.
- The DSi firmware stub is generated in the same way as the NDS firmware stub;
  this appears to be good enough for BlocksDS's dswifi to pick up the new AP
  definitions.
- The DSi NAND is currently not stubbed at all; rather, the code has been
  edited to allow bringup without a NAND image. This is sufficient for DSi
  mode homebrew; programs running from the cartridge slot are likewise not
  expected to require NAND access.

More work has to be done before it's useful for non-homebrew scenarios.

* Implement a less stub DSi::NeedsDirectBoot()

* Do not block direct boots if DSi NAND is missing but BIOS/firmware is present

* Correctly initialize extended header for DSi generated firmware

* Fix overriding firmware language in DSi mode, add experimental support for Chinese language option

Author: asiekierka

.gitignore

@@ -21,3 +21,7 @@ compile_commands.json
 .vscode
 CMakeFiles
 CMakeCache.txt
+
+freebios/FreeBIOS_Data.h
+freebios/bios*
+freebios/build/

freebios/Makefile

@@ -1,17 +1,44 @@
-TC_PREFIX  = /home/exophase/pandora-dev
-PREFIX     = $(TC_PREFIX)/arm-2011.03
-AS         = $(PREFIX)/bin/arm-none-linux-gnueabi-gcc
-OBJCOPY    = $(PREFIX)/bin/arm-none-linux-gnueabi-objcopy
+# SPDX-License-Identifier: CC0-1.0
+#
+# SPDX-FileContributor: Adrian "asie" Siekierka, 2025
 
-BIN_ARM7   = drastic_bios_arm7
-BIN_ARM9   = drastic_bios_arm9
+BIOS_FILE_NTR_ARM9 = bios_ntr_arm9.bin
+BIOS_FILE_NTR_ARM7 = bios_ntr_arm7.bin
+BIOS_FILE_TWL_ARM9 = bios_twl_arm9.bin
+BIOS_FILE_TWL_ARM7 = bios_twl_arm7.bin
 
-all:
-	$(AS) bios_common.S -DBIOS_ARM7 -march=armv4 -c -Wa,-asl=$(BIN_ARM7).list -o $(BIN_ARM7).o
-	$(AS) bios_common.S -DBIOS_ARM9 -march=armv5 -c -Wa,-asl=$(BIN_ARM9).list -o $(BIN_ARM9).o
-	$(OBJCOPY) -O binary $(BIN_ARM7).o $(BIN_ARM7).bin
-	$(OBJCOPY) -O binary $(BIN_ARM9).o $(BIN_ARM9).bin
+BIOS_FILES = \
+	$(BIOS_FILE_NTR_ARM9) \
+	$(BIOS_FILE_NTR_ARM7) \
+	$(BIOS_FILE_TWL_ARM9) \
+	$(BIOS_FILE_TWL_ARM7)
 
-clean:
-	rm -f $(BIN_ARM7).bin $(BIN_ARM7).o $(BIN_ARM9).bin $(BIN_ARM9).o
+BIOS_HEADERS = \
+	 $(patsubst %.bin,%.h,$(BIOS_FILES))
+
+BIOS_HEADER_ALL = FreeBIOS_Data.h
+
+.PHONY: all clean $(BIOS_FILES) $(BIOS_HEADER_ALL)
+
+all: $(BIOS_FILES) $(BIOS_HEADER_ALL)
+
+$(BIOS_HEADER_ALL): $(BIOS_FILES)
+	cat $(BIOS_HEADERS) > $(BIOS_HEADER_ALL)
 
+$(BIOS_FILE_NTR_ARM9):
+	$(MAKE) -f Makefile.bios TARGET=arm9 PLATFORM=ntr OUTPUT=$(BIOS_FILE_NTR_ARM9)
+
+$(BIOS_FILE_NTR_ARM7):
+	$(MAKE) -f Makefile.bios TARGET=arm7 PLATFORM=ntr OUTPUT=$(BIOS_FILE_NTR_ARM7)
+
+$(BIOS_FILE_TWL_ARM9):
+	$(MAKE) -f Makefile.bios TARGET=arm9 PLATFORM=twl OUTPUT=$(BIOS_FILE_TWL_ARM9)
+
+$(BIOS_FILE_TWL_ARM7):
+	$(MAKE) -f Makefile.bios TARGET=arm7 PLATFORM=twl OUTPUT=$(BIOS_FILE_TWL_ARM7)
+
+clean:
+	rm -fr build || true
+	rm -r $(BIOS_FILES) || true
+	rm -r $(BIOS_HEADERS) || true
+	rm -r $(BIOS_HEADER_ALL) || true

freebios/Makefile.bios

@@ -0,0 +1,119 @@
+# SPDX-License-Identifier: CC0-1.0
+#
+# SPDX-FileContributor: Antonio Niño Díaz, 2023
+# SPDX-FileContributor: Adrian "asie" Siekierka, 2025
+
+SOURCEDIRS	:= src src/$(TARGET)
+
+DEFINES		:= \
+	-DPLATFORM_$(shell echo $(PLATFORM) | tr a-z A-Z) \
+	-DTARGET_$(shell echo $(TARGET) | tr a-z A-Z)
+
+HEADER_OUTPUT	:= $(patsubst %.bin,%.h,$(OUTPUT))
+NAME		:= bios_$(PLATFORM)_$(TARGET)
+BUILDDIR	:= build/$(NAME)
+ELF		:= build/$(NAME).elf
+DUMP		:= build/$(NAME).dump
+MAP		:= build/$(NAME).map
+
+# Tools
+# -----
+
+PREFIX		:= arm-none-eabi-
+CC		:= $(PREFIX)gcc
+LD		:= $(PREFIX)gcc
+OBJCOPY		:= $(PREFIX)objcopy
+OBJDUMP		:= $(PREFIX)objdump
+
+# Verbose flag
+# ------------
+
+ifeq ($(VERBOSE),1)
+V		:=
+else
+V		:= @
+endif
+
+# Source files
+# ------------
+
+SOURCES_S	:= $(shell find -L $(SOURCEDIRS) -maxdepth 1 -name "*.s")
+SOURCES_C	:= $(shell find -L $(SOURCEDIRS) -maxdepth 1 -name "*.c")
+
+# Compiler and linker flags
+# -------------------------
+
+ifeq ($(TARGET),arm9)
+ARCH		:= -mthumb -mcpu=arm946e-s+nofp -Wl,--use-blx
+else
+ARCH		:= -mthumb -mcpu=arm7tdmi
+endif
+
+INCLUDEFLAGS	:= $(foreach path,$(INCLUDEDIRS),-I$(path))
+
+ASFLAGS		:= -x assembler-with-cpp $(DEFINES) $(INCLUDEFLAGS) \
+		   $(ARCH) -ffunction-sections -fdata-sections
+
+CFLAGS		:= $(WARNFLAGS) $(DEFINES) $(INCLUDEFLAGS) \
+		   $(ARCH) -ffunction-sections -fdata-sections -Os
+
+LDFLAGS		:= $(ARCH) -Wl,-Map,$(MAP) $(DEFINES) -nostdlib \
+		   -Wl,--gc-sections -Wl,--no-warn-rwx-segments
+
+LDFLAGS		+= -Wl,-Ttext 0x00000000 -Wl,-e 0x00000000
+
+# Intermediate build files
+# ------------------------
+
+OBJS		:= $(addsuffix .o,$(addprefix $(BUILDDIR)/,$(SOURCES_S))) \
+		   $(addsuffix .o,$(addprefix $(BUILDDIR)/,$(SOURCES_C)))
+
+DEPS		:= $(OBJS:.o=.d)
+
+# Targets
+# -------
+
+.PHONY: all dump
+
+all: $(OUTPUT) $(HEADER_OUTPUT)
+
+$(HEADER_OUTPUT): $(OUTPUT)
+	@echo "  XXD     $@"
+	$(V)xxd -i -n $(patsubst %.bin,%,$(OUTPUT)) -c 16 $(OUTPUT) $(HEADER_OUTPUT)
+
+$(OUTPUT): $(ELF)
+	@echo "  OBJCOPY $@"
+	$(V)$(OBJCOPY) -O binary $< $@
+
+$(ELF): $(OBJS)
+	@echo "  LD      $@"
+	$(V)$(LD) -o $@ $(OBJS) $(LDFLAGS)
+
+$(DUMP): $(ELF)
+	@echo "  OBJDUMP $@"
+	$(V)$(OBJDUMP) -h -C -S $< > $@
+
+dump: $(DUMP)
+
+# Rules
+# -----
+
+$(BUILDDIR)/%.s.o : %.s
+	@echo "  AS      $<"
+	@mkdir -p $(@D)
+	$(V)$(CC) $(ASFLAGS) -MMD -MP -c -o $@ $<
+
+$(BUILDDIR)/%.c.o : %.c
+	@echo "  CC      $<"
+	@mkdir -p $(@D)
+	$(V)$(CC) $(CFLAGS) -MMD -MP -c -o $@ $<
+
+$(BUILDDIR)/%.arm.c.o : %.arm.c
+	@echo "  CC      $<"
+	@mkdir -p $(@D)
+	$(V)$(CC) $(CFLAGS) -MMD -MP -marm -mlong-calls -c -o $@ $<
+
+# Include dependency files if they exist
+# --------------------------------------
+
+-include $(DEPS)