Reading and Decoding Data From ETB Buffer

[Ajay Bharadwaj]

Hi Mike,

Thanks for the quick reply!

On 12/01/21 11:37 pm, Mike Leach wrote:
[...]
>>>
>>> OpenCSD Output:
>>> Trace Packet Lister: CS Decode library testing
>>> -----------------------------------------------
>>>
>>> ** Library Version : 0.14.4
>>>
>>> Test Command Line:-
>>> ./tests/bin/linux64/dbg/trc_pkt_lister   -ss_dir
>>> tests/snapshots/stm_only/  -src_name  ETB_1
>>>
>>> Trace Packet Lister : reading snapshot from path tests/snapshots/stm_only/
>>> Using ETB_1 as trace source
>>> Trace Packet Lister : Protocol printer STM on Trace ID 0x1
>>> ID:1    END OF TRACE DATA
>>> Trace Packet Lister : Trace buffer done, processed 16384 bytes.
>>>
> 
> In general, if the trc_pkt_lister program doesn't find trace then
> there is none for the ID you have assigned to the STM in the snapshot
> .ini files.
> Try adding -o_raw_unpacked to your command line. Your will then see
> some output of raw bytes and associated trace ID as below..
> 
> Frame Data; Index  32704;   ID_DATA[0x20]; 83 01 6f ff ff ff 0c 01 06
> 10 7b 2b 6c ff

The problem was that the ETB buffer was overflowing and the initial
portion of the buffer was being overwritten. This was happening because
as soon as STM Source Console was enabled, the backlog of kernel
messages was being written to the STM_Console and flowing down to the ETB.

Reading from the ETB, and then writing to the STM_Console and reading
from the ETB again leads to this output while decoding:

Trace Packet Lister: CS Decode library testing
-----------------------------------------------

** Library Version : 0.14.4

Test Command Line:-
./tests/bin/linux64/dbg/trc_pkt_lister   -ss_dir
tests/snapshots/stm_only/  -src_name  ETB_1

Trace Packet Lister : reading snapshot from path tests/snapshots/stm_only/
Using ETB_1 as trace source
Trace Packet Lister : Protocol printer STM on Trace ID 0x1
Idx:0; ID:1;	NOTSYNC:STM not synchronised
Idx:16; ID:1;	NOTSYNC:STM not synchronised
Idx:32; ID:1;	NOTSYNC:STM not synchronised
Idx:48; ID:1;	NOTSYNC:STM not synchronised
Idx:64; ID:1;	NOTSYNC:STM not synchronised
Idx:80; ID:1;	NOTSYNC:STM not synchronised
Idx:96; ID:1;	NOTSYNC:STM not synchronised
Idx:112; ID:1;	NOTSYNC:STM not synchronised
ID:1	END OF TRACE DATA
Trace Packet Lister : Trace buffer done, processed 16384 bytes.

Is there any way to get around this and force the STM to send a
synchronization packet again without re-enabling the STM?

Is there already another tool or some setting for the Trace Packet
Lister that reverses the data and outputs it in a more human readable
format so that the decoded data is shown in the same way as the data
being written to the STM? This would make it much easier to use and
parse ftrace data, which is my end goal. Writing a script to do this
would be simple but a well maintained tool would be much better.

Input Data:
[   55.991806] printk: console [stm_console0] enabled
[   70.452733] AAAAAAAAAAAAAA

This what the output currently looks like:

Trace Packet Lister: CS Decode library testing
-----------------------------------------------

** Library Version : 0.14.4

Test Command Line:-
./tests/bin/linux64/dbg/trc_pkt_lister   -ss_dir
tests/snapshots/stm_only/  -src_name  ETB_1

Trace Packet Lister : reading snapshot from path tests/snapshots/stm_only/
Using ETB_1 as trace source
Trace Packet Lister : Protocol printer STM on Trace ID 0x1
Idx:0; ID:1;	ASYNC:Alignment synchronisation packet
Idx:11; ID:1;	VERSION:Version packet; Ver=3
Idx:13; ID:1;	FREQ:Frequency packet; Freq=0Hz
Idx:21; ID:1;	M8:Set current master; Master=0x44
Idx:22; ID:1;	D64TS:64 bit data + timestamp; Data=0x392e35352020205b;
TS=0x00000002E5004F22 ~[0x2E5004F22]
Idx:41; ID:1;	D64:64 bit data; Data=0x70205d3630383139
Idx:50; ID:1;	D64:64 bit data; Data=0x63203a6b746e6972
Idx:59; ID:1;	D64:64 bit data; Data=0x5b20656c6f736e6f
Idx:68; ID:1;	D64:64 bit data; Data=0x736e6f635f6d7473
Idx:77; ID:1;	D64:64 bit data; Data=0x6e65205d30656c6f
Idx:86; ID:1;	D32:32 bit data; Data=0x656c6261
Idx:91; ID:1;	D16:16 bit data; Data=0x0a64
Idx:93; ID:1;	FLAG:Flag packet
Idx:94; ID:1;	M8:Set current master; Master=0x43
Idx:97; ID:1;	D64TS:64 bit data + timestamp; Data=0x342e30372020205b;
TS=0x00000003915D477A ~[0x3915D477A]
Idx:113; ID:1;	D64:64 bit data; Data=0x41205d3333373235
Idx:122; ID:1;	D64:64 bit data; Data=0x4141414141414141
Idx:131; ID:1;	D32:32 bit data; Data=0x41414141
Idx:136; ID:1;	D16:16 bit data; Data=0x0a41
Idx:138; ID:1;	FLAG:Flag packet
ID:1	END OF TRACE DATA
Trace Packet Lister : Trace buffer done, processed 16384 bytes.

Regards,
Ajay