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https://github.com/Rockbox/rockbox.git
synced 2026-04-11 16:37:45 -04:00
d5506dfa22
Add a 'make start' target which starts Rockbox using a debugger. This only works to load the main binary, but makes it much faster to test changes that don't affect plugins/codecs. Because SDRAM isn't accessible at reset and the main binary is usually too big to fit in SRAM, the bootloader must be flashed first before Rockbox can be loaded in this way. The boot protocol involves GDB writing a check pattern to SRAM while the CPU is held in reset. The bootloader detects the pattern and takes a breakpoint, by which time SDRAM is accessible; GDB can then upload a binary ELF image (copied as a raw file, since the ELF will be loaded using RB's ELF loader) and leave the breakpoint to continue booting. From there the bootloader can load the ELF binary from memory, exactly like a normal SD card boot. Change-Id: I4eb971b4162ea422e38660455cfa0958cefaa18d
57 lines
1.7 KiB
Makefile
57 lines
1.7 KiB
Makefile
GDB := gdb
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OPENOCD := openocd
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OPENOCD_CFG := $(ROOTDIR)/tools/echoplayer/openocd.cfg
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# GDB boot protocol 'registers' used for communicating with the bootloader
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GDBBOOT_REG_BASE := 0x38000000
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GDBBOOT_REG_MAGIC1 := ($(GDBBOOT_REG_BASE) + 0x00)
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GDBBOOT_REG_MAGIC2 := ($(GDBBOOT_REG_BASE) + 0x04)
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GDBBOOT_REG_MAGIC3 := ($(GDBBOOT_REG_BASE) + 0x08)
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GDBBOOT_REG_MAGIC4 := ($(GDBBOOT_REG_BASE) + 0x0c)
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GDBBOOT_REG_ELFADDR := ($(GDBBOOT_REG_BASE) + 0x10)
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GDBBOOT_REG_ELFSIZE := ($(GDBBOOT_REG_BASE) + 0x14)
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# Address where the RB binary will be loaded
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GDBBOOT_LOAD_ADDR := 0x71e00000
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GDBBOOT_LOAD_SIZE := 0x200000
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ifneq (,$(findstring bootloader,$(APPSDIR)))
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TARGET_ELF := $(BUILDDIR)/bootloader.elf
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else
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TARGET_ELF := $(BUILDDIR)/rockbox.elf
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TARGET_BIN := $(BUILDDIR)/rockbox.echo
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endif
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# Attach to running process
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debug:
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$(GDB) $(TARGET_ELF) \
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-ex "target extended-remote | openocd -c \"gdb_port pipe\" -f $(OPENOCD_CFG)"
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.PHONY: debug
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ifneq (,$(findstring bootloader,$(APPSDIR)))
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# Flash bootloader
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flash: $(TARGET_ELF)
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$(OPENOCD) -f $(OPENOCD_CFG) -c "program $< verify reset exit"
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.PHONY: flash
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else
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# Start Rockbox via debugger
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start: $(TARGET_BIN)
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$(GDB) $(TARGET_ELF) \
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-ex "target extended-remote | openocd -c \"gdb_port pipe\" -f $(OPENOCD_CFG)" \
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-ex "monitor reset halt" \
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-ex "set *$(GDBBOOT_REG_MAGIC1) = 0x726f636b" \
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-ex "set *$(GDBBOOT_REG_MAGIC2) = 0x424f4f54" \
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-ex "set *$(GDBBOOT_REG_MAGIC3) = 0x6764626c" \
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-ex "set *$(GDBBOOT_REG_MAGIC4) = 0x6f616455" \
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-ex "continue" \
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-ex "restore $(TARGET_BIN) binary $(GDBBOOT_LOAD_ADDR)" \
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-ex "set *$(GDBBOOT_REG_ELFADDR) = $(GDBBOOT_LOAD_ADDR)" \
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-ex "set *$(GDBBOOT_REG_ELFSIZE) = $(GDBBOOT_LOAD_SIZE)" \
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-ex "continue"
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.PHONY: start
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endif
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