I am creating my own bootloader for an ATXmega128A4U. To use the bootloader I want to transform the ELF-file of the firmware into a memory map used in the the ATXmega. For that I use python and the modul "pyelftools". The documentation of it is poor and so I run into a problem: I do not know what information I can use to get the address, offset etc. from the data at the sections. My goal is to create a bytearray, copy the data/code into it and transfer it to the bootlaoder. Below is my code:
import sys
# If pyelftools is not installed, the example can also run from the root or
# examples/ dir of the source distribution.
sys.path[0:0] = ['.', '..']
from elftools.common.py3compat import bytes2str
from elftools.elf.elffile import ELFFile
# 128k flash for the ATXmega128a4u
flashsize = 128 * 1024
def process_file(filename):
with open(filename, 'rb') as f:
# get the data
elffile = ELFFile(f)
dataSec = elffile.get_section_by_name(b'.data')
textSec = elffile.get_section_by_name(b'.text')
# prepare the memory
flashMemory = bytearray(flashsize)
# the data section
startAddr = dataSec.header.sh_offset
am = dataSec.header.sh_size
i = 0
while i < am:
val = dataSec.stream.read(1)
flashMemory[startAddr] = val[0]
startAddr += 1
i += 1
# the text section
startAddr = textSec.header.sh_offset
am = textSec.header.sh_size
i = 0
while i < am:
print(str(startAddr) + ' : ' + str(i))
val = textSec.stream.read(1)
flashMemory[startAddr] = val[0]
startAddr += 1
i += 1
print('finished')
if __name__ == '__main__':
process_file('firmware.elf')
Hope someone can tell me how to solve this problem.
I manged to solve the problem. don't read the data manualy from the stream by "textSec.stream.read" use "textSec.data()" instead. Internaly (see "sections.py") a seek operation in the file is done. Afterwards the data is read. The result will be the valid data chunk. The following code reads the code(text) section of a atxmega firmware and copies it into a bytearray which has the layout of the flash of an atxmega128a4u device. @vlas_tepesch: the hex conversation is not needed and the the 64k pitfall is avoided.
sys.path[0:0] = ['.', '..']
from elftools.common.py3compat import bytes2str
from elftools.elf.elffile import ELFFile
# 128k flash for the ATXmega128a4u
flashsize = 128 * 1024
def __printSectionInfo (s):
print ('[{nr}] {name} {type} {addr} {offs} {size}'.format(
nr = s.header['sh_name'],
name = s.name,
type = s.header['sh_type'],
addr = s.header['sh_addr'],
offs = s.header['sh_offset'],
size = s.header['sh_size']
)
)
def process_file(filename):
print('In file: ' + filename)
with open(filename, 'rb') as f:
# get the data
elffile = ELFFile(f)
print ('sections:')
for s in elffile.iter_sections():
__printSectionInfo(s)
print ('get the code from the .text section')
textSec = elffile.get_section_by_name(b'.text')
# prepare the memory
flashMemory = bytearray(flashsize)
# the text section
startAddr = textSec.header['sh_addr']
val = textSec.data()
flashMemory[startAddr:startAddr+len(val)] = val
# print memory
print('finished')
if __name__ == '__main__':
process_file('firmware.elf')
Tanks for the comments!