.. highlight:: shell
.. index:: Ashling, SDP, AXS101, AXS102, AXS103, GDB
Using Ashling Opella-XD GDB server with AXS SDP
===============================================
.. note::
The Ashling GDB Server software for ARC is implemented by Ashling and
delivered as part of the Ashling Opella-XD probe for ARC processors
product. This guide aims to provide all necessary information to
successfully debug ARC applications using the GNU toolchain for ARC and the
Ashling GDB server, however for all issues related to the Ashling GDB
Server application, user should contact `Ashling Microsystems Ltd.
`_ for further assistance.
Ashling GDB Server can be used to debug application running on the AXS10x
family of software development platforms. It is recommended to use latest
version of Ashling drivers and software package available.
Building an application
-----------------------
To learn how to build applications for AXS SDP, please refer to corresponding
section of :ref:`OpenOCD manual `.
.. _axs-opella-board-configuration:
Board configuration
-------------------
Board should be configured mostly the same way as for the OpenOCD, but it is
required to change *JP1402* and *JP1403* jumpers - to debug with Opella-XD it is
required to set *JP1403* and unset *JP1402*, while for OpenOCD it is otherwise.
Refer to :ref:`OpenOCD manual ` and to the
User Guide of the AXC00x CPU card you are using for more details.
.. _run-ashling-gdb-server:
Running Ashling GDB Server
--------------------------
.. note::
Starting from Ashling ver. 1.2.6 **--device** option should contain specific cpu name of the board:
"arc-600", "arc-700", "arc-em", "arc-hs". Using simple "arc" would cause an error.
Options of the Ashling GDB Server are described in its User Manual. It is
highly recommended that users be familiar with Ashling GDB Server operation
before proceeding. In a nutshell, to run GDB Server with multiple cores in the
JTAG chain::
$ ./ash-arc-gdb-server --device arc --arc-reg-file \
--scan-file arc2core.xml --tap-number 1,2
Command for Ashling version starting from 1.2.6::
$ ./ash-arc-gdb-server --device arc-{CPU} --arc-reg-file \
--scan-file arc2core.xml --tap-number 1,2
where "arc-{CPU}" is equal to "arc-600", "arc-700", "arc-em", "arc-hs".
That will open GDB server connections on port 2331 (core 1) and 2332 (core 2).
Use GDB to connect to the core you want to debug. ```` is a path
to a file with AUX register definitions for the core you are going to debug.
Actual file that should be used depends on what target core is. A set of files
can be found in this ``toolchain`` repository in ``extras/opella-xd``
directory. In this directory there are ``arc600-cpu.xml``, ``arc700-cpu.xml``,
``arc-em-cpu.xml`` and ``arc-hs-cpu.xml`` files for GDB server, `direct link
`_.
To run with AXS101 with all four cores in a chain ::
$ ./ash-arc-gdb-server --device arc --arc-reg-file \
--scan-file arc4core.xml --tap-number 1,2,3,4
Command for Ashling version starting from 1.2.6::
$ ./ash-arc-gdb-server --device arc-{CPU} --arc-reg-file \
--scan-file arc4core.xml --tap-number 1,2,3,4
where "arc-{CPU}" is equal to "arc-600", "arc-700", "arc-em", "arc-hs".
File ``arc4core.xml`` is not shipped with Ashling GDB Server, but can be easily
created after looking at ``arc2core.xml`` and reading Ashling Opella-XD User
Manual.
To run Ashling GDB Server with JTAG chain of a single core::
$ ./ash-arc-gdb-server --device arc --arc-reg-file
Command for Ashling version starting from 1.2.6::
$ ./ash-arc-gdb-server --device arc-{CPU} --arc-reg-file
where "arc-{CPU}" is equal to "arc-600", "arc-700", "arc-em", "arc-hs".
Option ``--jtag-frequency ...MHz`` can be passed to gdbserver to change JTAG
frequency from default 1MHz. Rule of the thumb is that maximum frequency can
be no bigger than half of the frequency, but for cores with external memory
that value can be much lower. Most of the cores in different SDP models can
work safely with JTAG frequencies around 10 ~ 12 MHz. ARC EM6 in the AXS101 is
an exception - maximum recommended frequency is 5MHz.
Running GDB
-----------
Run GDB::
$ arc-elf32-gdb ./application.to.debug
Then it is required to specify description of target core that will be debugged
with Ashling GDB Server.
Then it is required to specify XML target description file appropriate for the
``ARC_REG_FILE`` used to start Ashling GDB server. XML target description files
for ``arc600-cpu.xml``, ``arc700-cpu.xml``, ``arc-em-cpu.xml`` and
``arc-hs-cpu.xml`` can be found in this ``toolchain`` repository in
``extras/opella-xd``, `direct link
`_.
Provided files are: ``opella-arc600-tdesc.xml``, ``opella-arc700-tdesc.xml``,
``opella-arcem-tdesc.xml`` and ``opella-archs-tdesc.xml``.
File ``aux-minimal.xml`` should be also downloaded from that folder
and put into the same folder as ``opella-*-tdesc.xml``. This file
contains description common to all architectures and is included by all
"tdesc" files.
It is important that ``ARC_REG_FILE`` for Ashling GDB server and target
description file for GDB match each other, so if Opella's file has been
modified, so should be the target description.::
(gdb) set tdesc filename
Connect to the target GDB server::
(gdb) target remote :
where ```` is a hostname/IP-address of the host that runs OpenOCD
(can be omitted if it is localhost), and ```` is a number of port of
the core you want to debug (see previous section).
In most cases you need to load application into the target::
(gdb) load
The system is now ready to debug the application.
To debug several cores on the AXC00x card simultaneously, start
additional GDBs and connect to the required TCP ports. Cores are controlled
independently from each other.
.. _known-issues:
Known issues
------------
* XML register file is specified only once in the GDB Server argument, that
means that if your JTAG chain includes multiple cores of different model
(e.g. ARC 700 and EM) you cannot debug them simultaneously, but you can debug
multiple cores of they same type (e.g. all EM).
* GDB on Windows can't read XML files with Windows line endings (CR/LF) - tdesc
XML file must be converted to UNIX line endings (LF).
* HS36 core of the AXS102 cannot be used when both cores are in the JTAG chain
- if "resume" operation is initiated on the core, GDB Server and GDB will
behave like it is running and never halting, but in reality it never started
to run. To workaround this issue remove HS34 from the JTAG chain (remove
JP1200 jumper on the AXC002 card, remove ``--scan-file`` and ``--tap-number``
options from Ashling GDB Server command line). If you need both HS34 and HS36
in the JTAG chain use OpenOCD instead of Ashling GDB Server. Why this problem
happens is a mystery, since HS36 works without problems when it is single in
the JTAG chain, and HS34 always work fine; this is likely a problem with
Ashling GDB Server.
* In Opella software version of 1.0.6 prior to 1.0.6-D it has been observed
that in some cases target core may hang on application load, if target has
external memory attached. This happens when P-packet is disabled, and since
P-packet should be disabled when using new GDB with those versions of Opella
software, effectively it is not possible to use GDB >= 7.9 with Ashling
GDBserver < 1.0.6-D to debug cores that employ external memory.
* In version of 1.0.6 it has been observed that breakpoint set at ``main()``
function of application may be not hit on first run in HS34 core in AXS102.
* In version 1.0.6-D it has been observed that gdbserver doesn't invalidate I$
of the second ARC 600 core of AXS101 - if this core hits a software
breakpoint it gets stuck at it forever.
* On Windows Ashling might not work at the beginning. After installing Ashling
software try to run ``opxdarc.exe`` application. If it fails to start with error
like "mfc110.dll missing" try to install "Visual C++ Redistributable for Visual
Studio". When ``opxdarc.exe`` application was launched press ``Connect`` button.
If in the list ``Serial Number`` the message ``No Opella-XD Found`` appears
go to device manager and check if Ashling driver is installed correctly.
If not try to update Ashling driver setting search location with the path
to installed Ashling software.
Known Issues of previous versions of Ashling software
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
* In version of Ashling software up to 1.0.5B, passing option ``--tap-number
2`` will cause GDB Server to print that it opened connection on port 2331 for
core 2, however that is not true, instead GDB Server will create this
connection for core 1. Therefore if your JTAG chain contains multiple ARC
TAPs you _must_ specify all of them in the argument to ``--tap-number``
option.
* Up to version 1.0.5F there is an error in handling of 4-byte software
breakpoints at 2-byte aligned addresses. For example in this sample of code
attempt to set breakpoint at 0x2b2 will fail.::
0x000002b0 <+0>: push_s blink
0x000002b2 <+2>: st.a fp,[sp,-4]
0x000002b6 <+6>: mov_s fp,sp
0x000002b8 <+8>: sub_s sp,sp,16
* Big endian ARC v2 cores are not supported on versions prior to 1.0.5-F.