Hi Hugh,
On Mon, 28 Mar 2022 at 11:41, Hugh O'Keeffe hugh.okeeffe@ashling.com wrote:
Hi Al and Mike,
Appreciate your response. It seems that OpenCSD and CSAL are very similar. Are they two different approaches to solving the same problem OR in fact are they inherently different? I note that OpenCSD appears to actually decode trace as well (which CSAL does not appear to support).
CSAL primarily configures and programs CoreSight components using the memory interface. Either bare metal, or under linux if the correct memory access is allowed by the kernel configuration. It also has a bunch of example programs demonstrating usage of the library, and extracting trace on certain platforms.
OpenCSD decodes any collected trace. It does not do any configuration - but requires certain trace configuration values to be provided in order to do the decode - alongside memory images if full CPU instruction trace decode is required. It does not do any data presentation or correlation - that is for any client application to do - though it does have packet printing routines that will give a human readable version of the decoded packets.
OpenCSD is used by perf in linux to do all the decode for this tool.
OpenCSD does come with its own standalone test program trc_pkt_lister - which will decode trace snapshots and output packets in the readable format mentioned above. These snapshots consist of trace data buffers + a set of .ini type files that contain the configuration of the hardware, and the memory images needed for full decode. If packet decode only is required then the memory images can be omitted. The specification for trace snapshots is provided in the OpenCSD github repository, and example snapshots are also in the repository.
There is no current ELA600 driver in the kernel - and I am unsure if there is one in development. If your ELA600 is configured to output to the Coresight trace bus - then configuring using CSAL / decoding using OpenCSD would be a possible path. If it is configured to use its own internal RAMs then OpenCSD will not help.
As Al mentions, the actual format of any given ELA data is SoC specific - so interpretation will have to be customized.
Assuming you configure and get the device to trace into an ETR / ETF then this data will be multiplexed into the CoreSight frame format - on an ATID basis. OpenCSD could help here in that the front end will demultiplex the data to produce a byte stream input for a decoder based on the ATID. OpenCSD contains an API that allows custom decoders to be registered with the library. Thus an ELA decoder can be registered, then an instance attached to the ATID being used for the ELA600 and the library would feed the demultiplexed stream to the decoder. Alternatively, it should be relatively easy to write a simple program using the library demux components to take in a formatted buffer and output a binary file of raw data for a given ATID.
Regards
Mike
Would appreciate any pointers or comments as to how they compare and what would be my best starting point.
Thanks Hugh
-----Original Message----- From: Al Grant Al.Grant@arm.com Sent: Friday 25 March 2022 09:49 To: Mike Leach mike.leach@linaro.org; Hugh O'Keeffe hugh.okeeffe@ashling.com Cc: coresight@lists.linaro.org Subject: RE: CoreSight ELA-600 Embedded Logic Analyzer
On Thu, 24 Mar 2022 at 17:47, Hugh O'Keeffe hugh.okeeffe@ashling.com wrote:
Hi All,
Couple of questions:
- Does anyone know of any other software options other than DS-5
for
configuring, capturing and viewing data using the ELA-600 ?
In https://github.com/ARM-software/CSAL, the csscan.py script has some basic support for reading the ELA config and dumping its SRAM buffer. No support for decoding ELA capture out of a CoreSight trace stream though, as it was only tested on ELA-500.
The assignment of input signals may be SoC-specific and there may also be SoC-specific obfuscation applied to the data - this is one of those "ask your SoC vendor" situations. The scripts that have gone upstream don't reveal anything that is not already public.
Al
- I could roll my own but I don't think OpenCSD has support for the
ELA-
- Correct ?
As I maintain OpenCSD I can answer this second question....
No - there is not an ELA specific decoder in OpenCSD. Nor are there plans to add one at present. That said the the OpenCSD infrastucture should allow a new decode module to be added easily.
Regards
Mike
Thanks in advance
Hugh
-----Original Message----- From: coresight-request@lists.linaro.org coresight-request@lists.linaro.org Sent: Thursday 24 March 2022 17:36 To: Hugh O'Keeffe hugh.okeeffe@ashling.com Subject: Welcome to the "CoreSight" mailing list
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