Re: [Openocd-development] 'flash write_image' and 'verify_image' commands fail if there are no more hardware breakpoints available

[Dario V. <dar...@ti...>]

> You could define a few step/breakpoint commands in tcl that has this
> functionality. The existing functions would then be the low level implementation
> of hardware/software breakpoints.

with the "breakpoints list/save/restore" patch one can use a similar script:

----------------------------------------------------------------------------
reset
sleep 1000

arm7_9 fast_memory_access enable
arm7_9 dcc_downloads enable
str9x flash_config 0 4 2 0 0x80000

# save breakpoints
bpsave bp.bpt
# remove all breakpoints
rbp

flash protect 0 0 7 off
flash write_image erase prog.elf
flash protect 0 0 7 on

verify_image prog.elf

# restore breakpoints
script bp.bpt

resume

----------------------------------------------------------------------------

> This isn't a problem when debugging with GDB, is it?

no

> How do you propose to deal with this from a users point of view?

The first issue for users (like me) is to be aware of risks and problems.
When a user execute:

> load_image zero.img 0x50000000 bin
256 byte written at address 0x50000000
downloaded 256 byte in 0.015625s

openocd says everything is ok but is not (not always) true.

Some idea can be:

- In the default scripts add a comment like "this area is reserved for the
  debugger and should not be used by the application"
- Set 'backup' as default
- In the default scripts set a 'working_area' at the end of internal SRAM
  (where is the stack? where is the heap?)
- chek overlapping of 'working_area' and image load in the load_image implementation (this should be 
easy and mandatory)
  - if possible, allocate the 'working_area' needed for the algorithm outside
    of the loading image space (but inside the 'working_area' defined in the config file)
  - if not enough space (e.g. the loading image space completely overlaps the
    'working_area' defined in the config file) give an error and do not load
    or load without dcc (or at least tell the user to disable dcc)

Regards,
        Dario