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1a200ead4f
The rt-loader currently only supports booting piggy backed lzma compressed kernels. This requires a data layout where the kernel directly follows the loader. That might not be sufficient for more complex flash layouts. Especially bootbase devices (like ZyXEL GS1920) will need some kind of chain loading that needs to be explored yet. Enhance the rt-loader as follows: - Allow to build as standalone version - In this case a flash start address is given - During boot loader will search the ROM starting from that address - If it finds a uImage this will be loaded into RAM - Afterwards it will be decompressed to its load address - While we are here add uncompressed uImage support As always the implementation tries to be as simple as possible. - uImage detection works without magics - uImage will be loaded to highest possible memory address - Documentation in Makefile has been adapted accordingly Funny side fact: A standalone rt-loader can chain load a piggy backed rt-loader from flash. During bootup loader will show rt-loader Running on RTL8380M (chip id 6275C) with 256MB Relocate 15760 bytes from 0x82000000 to 0x8ffa0000 Searching for uImage starting at 0xb45a0000 ... uImage 'MIPS OpenWrt Linux-6.12.40' found at 0xb45a0000 with load address 0x80100000 Copy 2923034 bytes of image data to 0x8fcd61e6 ... Extract image with 2923034 bytes from 0x8fcd61e6 to 0x80100000 ... Final kernel size is 2923034 bytes Booting kernel from 0x80100000 ... Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Link: https://github.com/openwrt/openwrt/pull/19832 Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
124 lines
3.8 KiB
Makefile
124 lines
3.8 KiB
Makefile
# rt-loader make file
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# (c) 2025 Markus Stockhausen
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#
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# This is the make file for the rt-loader (aka runtime or realtek loader). It tries to
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# avoid copying files around where possible. Therefore it is controlled by the following
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# input parameters
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#
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# KERNEL_IMG_IN: The filename of an LZMA compressed kernel. If given the loader
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# and the kernel will be concatenated (piggy back loading).
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# FLASH_ADDR: The kernel address in the ROM. If given, the loeader will be
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# created standalone and search a LZMA compressed uImage on the
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# target device starting from this address.
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# KERNEL_IMG_OUT: The filename of the kernel image with the rt-loader prepended.
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# If not given it will be created as image.bin into the BUILD_DIR.
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# BUILD_DIR: The temporary build dir. If not given it will be set to "build".
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#
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# To add it into the OpenWrt toolchain just create the following new build commands
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#
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# define Build/rt-compress
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# $(STAGING_DIR_HOST)/bin/xz --format=lzma -9 --stdout "$@" > "$@.new"
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# mv "$@.new" "$@"
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# endef
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#
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# define Build/rt-loader-piggy-back
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# $(MAKE) all clean -C rt-loader CROSS_COMPILE="$(TARGET_CROSS)" \
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# KERNEL_IMG_IN="$@" KERNEL_IMG_OUT="$@.new" BUILD_DIR="$@.build"
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# mv "$@.new" "$@"
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# endef
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#
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# define Build/rt-loader-standalone
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# $(MAKE) all clean -C rt-loader CROSS_COMPILE="$(TARGET_CROSS)" \
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# FLASH_ADDR=$(FLASH_ADDR) KERNEL_IMG_OUT="$@.new" BUILD_DIR="$@.build"
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# mv "$@.new" "$@"
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# endef
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#
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# Finally use them in new kernel build recipes. E.g. as all-in-one self extracting uImage.
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#
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# define Device/uimage-rt-loader
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# KERNEL/rt-loader := kernel-bin | append-dtb | rt-compress | rt-loader-piggy-back
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# KERNEL := $$(KERNEL/rt-loader) | uImage none
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# KERNEL_INITRAMFS := $$(KERNEL/rt-loader) | uImage none
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# endef
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#
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# Or as direct startable standlone version plus a kernel uImage
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#
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# define Device/rt-loader-uimage
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# FLASH_ADDR := 0xb4000000
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# KERNEL/rt-loader := rt-loader-standalone
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# KERNEL := kernel-bin | append-dtb | rt-compress | uImage lzma
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# endef
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FLASH_ADDR_NONE := 0x0
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FLASH_ADDR ?= $(FLASH_ADDR_NONE)
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CC := $(CROSS_COMPILE)gcc
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LD := $(CROSS_COMPILE)ld
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OBJCOPY := $(CROSS_COMPILE)objcopy
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OBJDUMP := $(CROSS_COMPILE)objdump
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CFLAGS = -fpic -mabicalls -O2 -fno-builtin-printf -Iinclude
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CFLAGS += -DFLASH_ADDR=$(FLASH_ADDR)
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ASFLAGS = -fpic -msoft-float -Iinclude
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LDFLAGS = -static -nostdlib -T linker/linker.ld --no-warn-mismatch
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O_FORMAT = $(shell $(OBJDUMP) -i | head -2 | grep elf32)
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SOURCES = src/startup.S src/main.c src/board.c src/memory.c src/unlzma.c
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BUILD_DIR ?= build
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IMAGE_OBJ := $(BUILD_DIR)/image.o
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IMAGE_ELF := $(BUILD_DIR)/image.elf
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KERNEL_IMG_NONE := $(BUILD_DIR)/empty_kernel.bin
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KERNEL_IMG_IN ?= $(KERNEL_IMG_NONE)
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KERNEL_IMG_OUT ?= $(BUILD_DIR)/image.bin
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OBJECTS_C = $(filter %.c,$(SOURCES))
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OBJECTS_S = $(filter %.S,$(SOURCES))
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OBJECTS := $(OBJECTS_S:.S=.o) $(OBJECTS_C:.c=.o)
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OBJECTS := $(patsubst %.o, $(BUILD_DIR)/%.o, $(OBJECTS)) $(IMAGE_OBJ)
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ifneq ($(MAKECMDGOALS),clean)
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ifeq ($(KERNEL_IMG_IN)$(FLASH_ADDR),$(KERNEL_IMG_NONE)$(FLASH_ADDR_NONE))
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$(error Set either KERNEL_IMG_IN or FLASH_ADDR)
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else ifneq ($(FLASH_ADDR),$(FLASH_ADDR_NONE))
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$(info Create standalone rt-loader, loading uimage from address $(FLASH_ADDR))
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else
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$(info Create piggy backed rt-loader, loading appended kernel binary "$(KERNEL_IMG_IN)")
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endif
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endif
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all: $(KERNEL_IMG_OUT)
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install:
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$(BUILD_DIR)/%.o : %.c
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@mkdir -p $(dir $@)
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$(CC) $(CFLAGS) -c -o $@ $<
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$(BUILD_DIR)/%.o : %.S
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@mkdir -p $(dir $@)
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$(CC) $(ASFLAGS) -c -o $@ $<
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$(IMAGE_OBJ): $(KERNEL_IMG_IN)
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$(OBJCOPY) -I binary -O $(O_FORMAT) --rename-section .data=.kernel $< $@
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$(IMAGE_ELF): $(OBJECTS)
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$(LD) $(LDFLAGS) -o $@ $(OBJECTS)
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$(KERNEL_IMG_OUT): $(IMAGE_ELF)
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$(OBJCOPY) -O binary $< $@
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$(KERNEL_IMG_IN):
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@mkdir -p $(dir $@)
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@echo "DUMMY-KERNEL-IMAGE" > $@
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clean:
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rm -rf $(BUILD_DIR)/
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