thanks, just a couple tweaks On Mon, Mar 29, 2021 at 12:13 PM Christian Mauderer <o...@c-mauderer.de> wrote: > > --- > user/bsps/arm/beagle.rst | 67 ++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 65 insertions(+), 2 deletions(-) > > diff --git a/user/bsps/arm/beagle.rst b/user/bsps/arm/beagle.rst > index ac49b1c..dedd01b 100644 > --- a/user/bsps/arm/beagle.rst > +++ b/user/bsps/arm/beagle.rst > @@ -102,8 +102,8 @@ The function prototype is given below: > rtems_vector_number irq > ); > > -Debugging > ---------- > +Debugging using libdebugger > +--------------------------- > > RTEMS's ``libdebugger`` requires the ARM debug resources be enabled for it to > work. The TI SOC used on the ``beagleboneblack`` board provides no access for > @@ -162,3 +162,66 @@ If ``libdebugger`` fails to detect the registers open > the ``bspdebug.c`` > source and change ``has_tdo`` to ``1``, save then rebuild and install the > BSP. This will turn on an internal feeback to check the JTAG logic. Discard > the edit once the hardware is working. > + > +Debugging Beagle Bone Black using a JTAG debugger and gdb > +--------------------------------------------------------- > + > +Debugging a Beagle Bone Black (or variants) is also possible using a hardware > +JTAG debugger. The JTAG is available via P2. The connector is thought for a 'thought for'? through?
> +ARM 20 pin cTI connector. That connector should be used, if it is relevant to relevant -> necessary > +have access to commercially available adapters. > + > +For hand-made cables and adapters a standard 1.27mm pitch header and a > 0.635mm > +ribbon cable can be much cheaper. But note that even if it looks compatible, > +it's not the same pin out as a ARM Cortex 20 pin connector! > + > +A lot of JTAG adapters that are working together with OpenOCD will work. > There > +are also commercially available systems (like Segger J-Link) that work well > with > +the Beagle. Note that the JTAG debugger has to be compatible with ARM Cortex > A8. > +Cortex M only debuggers (like the Segger J-Link Edu Mini) won't work. > + > +If the debugger offers a gdb server (like OpenOCD or Segger J-Link) the > +following gdb start script can be used: > + > +.. code-block:: > + > + define reset > + echo -- Reset target and wait for U-Boot to start kernel.\n > + monitor reset > + # RTEMS U-Boot starts at this address. > + tbreak *0x80000000 > + # Linux starts here. > + tbreak *0x82000000 > + continue > + > + echo -- Disable watchdog.\n > + set *(uint32_t*)0x44e35048=0xAAAA > + while (*(uint32_t*)0x44e35034 != 0) > + end > + set *(uint32_t*)0x44e35048=0x5555 > + while (*(uint32_t*)0x44e35034 != 0) > + end > + > + echo -- Overwrite kernel with application to debug.\n > + load > + end > + > + target remote :2331 > + > +Note that you might have to replace the ``monitor reset`` by some other > command > +that resets the target using your specific debugger. You also have to replace > +the ``target remote :2331`` to match the port of your gdb server. > + > +The script expects that the Beagle Bone Black starts some application from > an SD > +card or from eMMC. It defines a ``reset`` command that does the following: > + > + * reset the target > + * let U-Boot run, initialize the base system, load an FDT and an application > + * break at the application entry point > + * disable the watchdog > + * overwrite the application that has been loaded by U-Boot with the > application > + provided as an command line argument to gdb > + > +This method has the advantage that the application is executed in nearly > exact delete exact > +the same environment like it would be executed if loaded by U-Boot directly > +(except for the watchdog). > -- > 2.30.2 > > _______________________________________________ > devel mailing list > devel@rtems.org > http://lists.rtems.org/mailman/listinfo/devel _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
