In particular, the default image file is changed from .hex to .elf. I don't know of any boards that do any special magic translations of the elf file when creating the hex. Flashing should work correctly for any board which have fully working GDB debugging through OpenOCD, because that means that the symbols are loading properly from the ELF file.

I like this PR! It comes in the moment I'm actually working on a solution to force all (openocd-flashed) boards to flash bin (easier to distribute for updates). My current solution is:

do_flash_bin() {
    test_config
    test_binfile
    if [ -n "${PRE_FLASH_CHECK_SCRIPT}" ]; then
        sh -c "${PRE_FLASH_CHECK_SCRIPT} '${HEXFILE}'"
        RETVAL=$?
        if [ $RETVAL -ne 0 ]; then
            echo "pre-flash checks failed, status=$RETVAL"
            exit $RETVAL
        fi
    fi
    # flash device
    sh -c "${OPENOCD} -f '${OPENOCD_CONFIG}' \
            ${OPENOCD_EXTRA_INIT} \
            -c 'tcl_port 0' \
            -c 'telnet_port 0' \
            -c 'gdb_port 0' \
            -c 'init' \
            -c 'targets' \
            -c 'reset halt' \
            ${OPENOCD_PRE_FLASH_CMDS} \
            -c 'program \"${BINFILE}\" \"${FLASH_ADDR}\"' \
            -c 'reset halt' \
            ${OPENOCD_PRE_VERIFY_CMDS} \
            -c 'verify_image \"${BINFILE}\" \"${FLASH_ADDR}\" bin' \
            -c 'reset run' \
            -c 'shutdown'" &&
    echo 'Done flashing'
}

Which can be also merged to the HEX or ELF solutions, except for the command, which is program instead of flash.

So, in summary, I like the work but I don't see a strong reason to flash always ELF, however I do agree that we don't need to flash HEX for openocd flashing.

It should be easy to refactor this in a follow up to support setting the base address that you need for bin flashing.

My main motivation for this was to make it possible to run ddd automatically and to prepare for an upcoming separation of board configuration from debug interface adapter configuration, which will be useful to reduce code duplication in the repo, as well as being able to use any freestanding jtag/swd adapter for programming any board (especially useful for custom boards without integrated debug adapters)

@kYc0o btw, you should not need to switch to the program command in openocd, it should be enough to put your flash base address as an extra argument after the file name to flash write_image.

@kYc0o btw, you should not need to switch to the program command in openocd, it should be enough to put your flash base address as an extra argument after the file name to flash write_image.

Ok I see, but then I need to provide also the type, which is not harmful... thanks for the hint!

So, In short, can we use this PR for the default debugging interface but maybe we use bin for the flash command? Are these two necessarily together? I think flashing bin and debugging with ELF is possible and would ease other procedures like bin file distribution.

I don't like the idea of using bin as the default. Bin is just a raw memory dump with no extra information. Also since it's a raw dump it doesn't support memory holes. It is way easier to mess up a flash unintentionally when you don't have any header information for the image.
I don't mind providing bin as an option though.
How about this:

• Rename ELFFILE -> IMAGE_FILE, in flashing only
• Introduce IMAGE_OFFSET and IMAGE_TYPE, both optional, default is 0 for offset and empty string for type (means openocd will figure out from the file automatically)
• Keep ELFFILE for debug target
• Default value for IMAGE_FILE is $ELFFILE
• Add file existence check for IMAGE_FILE in flashing only.

In a future PR:

• Search the boards tree for HEXFILE definitions and remove them when they do not add any value to the board. I noticed that some boards seem to specify various special image builds even though they use the regular openocd script for flashing, I don't know why this was done so or if it's just a remnant from some ancient Makefile before the openocd tool usage was consolidated.

How about this:

Rename ELFFILE -> IMAGE_FILE, in flashing only
Introduce IMAGE_OFFSET and IMAGE_TYPE, both optional, default is 0 for offset and empty string for type (means openocd will figure out from the file automatically)
Keep ELFFILE for debug target
Default value for IMAGE_FILE is $ELFFILE
Add file existence check for IMAGE_FILE in flashing only.

It seems perfect to me, I didn't considered having a mess in the resulting binary since the goal is to generate it exactly in the same way as the HEX are generated (using objcopy), so for me it seemed legit. However I prefer you solution since it avoids any mistake if a different binary is loaded.

In a future PR:

Search the boards tree for HEXFILE definitions and remove them when they do not add any value to the board. I noticed that some boards seem to specify various special image builds even though they use the regular openocd script for flashing, I don't know why this was done so or if it's just a remnant from some ancient Makefile before the openocd tool usage was consolidated.

I'd like to do that job.

@kYc0o
Added IMAGE_TYPE, IMAGE_FILE, IMAGE_OFFSET
Updated mulle to use the check elf-file script instead of hex. The other Kinetis boards already used the elf version.

Perfect, will test very soon.

Please squash, I think this is ready.

Will rebase tomorrow

squashed

Amended a small documentation error (ELFFILE vs. IMAGE_FILE in the docs for the flash command)

Let's go for #7686

Thanks @kYc0o