pico_build/bs2_default/BUILD.gn

import("//build_overrides/pigweed.gni")

import("$dir_pw_build/target_types.gni")

_pico_sdk_dir = rebase_path(dir_third_party_pico_sdk)

pw_executable("bs2_default") {
  defines = [
    "PICO_H_LOCATION=\"${_pico_sdk_dir}/src/boards/include/boards/pico.h\"",
    "RENAME_EXCEPTIONS_H_LOCATION=\"$_pico_sdk_dir/src/rp2_common/cmsis/include/cmsis/rename_exceptions.h\"",
    "PICO_BOARD=\"pico\"",
    "PICO_BUILD=1",
    "PICO_NO_HARDWARE=0",
    "PICO_ON_DEVICE=1",
  ]
  asmflags = [
    "-mcpu=cortex-m0plus",
    "-mthumb",
    "-O3",
    "-DNDEBUG",
  ]
  include_dirs = [
    "${_pico_sdk_dir}/src/boards/include",
    "${_pico_sdk_dir}/src/common/pico_base/include",
    "${_pico_sdk_dir}/src/rp2040/hardware_regs/include",
    "${_pico_sdk_dir}/src/rp2_common/boot_stage2/asminclude",
    "${_pico_sdk_dir}/src/rp2_common/boot_stage2/include",
    "${_pico_sdk_dir}/src/rp2_common/hardware_base/include",
    "${_pico_sdk_dir}/src/rp2_common/pico_platform/include",
    "$dir_pico_build/public_overrides",
  ]
  sources =
      [ "${_pico_sdk_dir}/src/rp2_common/boot_stage2/compile_time_choice.S" ]
  ldflags = [
    "-Wl,--build-id=none",
    "-nostartfiles",
    "-Wl,--script=${_pico_sdk_dir}/src/rp2_common/boot_stage2/boot_stage2.ld",
    "-Wl,-Map=bs2_default.elf.map",
  ]
}

# Followup steps for bs2_default.elf

# 1. arm-none-eabi-objdump -h bs2_default.elf >bs2_default.dis
# 2. arm-none-eabi-objdump -d bs2_default.elf >>bs2_default.dis
# 3. Generating bs2_default.bin
#   cd pico-sdk/src/rp2_common/boot_stage2 &&
#   ../../../../../.environment/cipd/pigweed/bin/arm-none-eabi-objcopy
#   -Obinary
#   /home/tonymd/pico/picohellousbserial/outcmake/pico-sdk/src/rp2_common/boot_stage2/bs2_default.elf
#   /home/tonymd/pico/picohellousbserial/outcmake/pico-sdk/src/rp2_common/boot_stage2/bs2_default.bin
# 4. Generating bs2_default_padded_checksummed.S
#   cd pico-sdk/src/rp2_common/boot_stage2 &&
#   /usr/bin/python3.8
#   ./picohellousbserial/third_party/pico-sdk/src/rp2_common/boot_stage2/pad_checksum
#   -s 0xffffffff
#   ./picohellousbserial/outcmake/pico-sdk/src/rp2_common/boot_stage2/bs2_default.bin
#   ./picohellousbserial/outcmake/pico-sdk/src/rp2_common/boot_stage2/bs2_default_padded_checksummed.S