Re: [PATCH v14 0/9] Coresight: Add support for TPDM and TPDA
From: Suzuki K Poulose
Date: Tue Nov 08 2022 - 04:41:14 EST
On 08/11/2022 09:37, Suzuki K Poulose wrote:
On 08/11/2022 05:54, Jinlong Mao wrote:
On 11/8/2022 2:38 AM, Suzuki K Poulose wrote:
On 02/11/2022 09:19, Mao Jinlong wrote:
This series adds support for the trace performance monitoring and
diagnostics hardware (TPDM and TPDA). It is composed of two major
elements.
a) Changes for original coresight framework to support for TPDM and
TPDA.
b) Add driver code for TPDM and TPDA.
Introduction of changes for original coresight framework
Support TPDM as new coresight source.
Since only STM and ETM are supported as coresight source originally.
TPDM is a newly added coresight source. We need to change
the original way of saving coresight path to support more types source
for coresight driver.
The following patch is to add support more coresight sources.
coresight: core: Use IDR for non-cpu bound sources' paths.
---8>---
Introduction of TPDM and TPDA
TPDM - The trace performance monitoring and diagnostics monitor or
TPDM in
short serves as data collection component for various dataset types
specified in the QPMDA(Qualcomm performance monitoring and diagnostics
architecture) spec. The primary use case of the TPDM is to collect data
from different data sources and send it to a TPDA for packetization,
timestamping and funneling.
Coresight: Add coresight TPDM source driver
dt-bindings: arm: Adds CoreSight TPDM hardware definitions
coresight-tpdm: Add DSB dataset support
coresight-tpdm: Add integration test support
docs: sysfs: coresight: Add sysfs ABI documentation for TPDM
TPDA - The trace performance monitoring and diagnostics aggregator or
TPDA in short serves as an arbitration and packetization engine for the
performance monitoring and diagnostics network as specified in the
QPMDA
(Qualcomm performance monitoring and diagnostics architecture)
specification. The primary use case of the TPDA is to provide
packetization, funneling and timestamping of Monitor data as specified
in the QPMDA specification.
The following patch is to add driver for TPDA.
Coresight: Add TPDA link driver
dt-bindings: arm: Adds CoreSight TPDA hardware definitions
The last patch of this series is a device tree modification, which add
the TPDM and TPDA configuration to device tree for validating.
ARM: dts: msm: Add coresight components for SM8250
ARM: dts: msm: Add tpdm mm/prng for sm8250
Once this series patches are applied properly, the tpdm and tpda nodes
should be observed at the coresight path /sys/bus/coresight/devices
e.g.
/sys/bus/coresight/devices # ls -l | grep tpd
tpda0 -> ../../../devices/platform/soc@0/6004000.tpda/tpda0
tpdm0 -> ../../../devices/platform/soc@0/6c08000.mm.tpdm/tpdm0
We can use the commands are similar to the below to validate TPDMs.
Enable coresight sink first.
echo 1 > /sys/bus/coresight/devices/tmc_etf0/enable_sink
echo 1 > /sys/bus/coresight/devices/tpdm0/enable_source
echo 1 > /sys/bus/coresight/devices/tpdm0/integration_test
echo 2 > /sys/bus/coresight/devices/tpdm0/integration_test
The test data will be collected in the coresight sink which is enabled.
If rwp register of the sink is keeping updating when do
integration_test (by cat tmc_etf0/mgmt/rwp), it means there is data
generated from TPDM to sink.
There must be a tpda between tpdm and the sink. When there are some
other trace event hw components in the same HW block with tpdm, tpdm
and these hw components will connect to the coresight funnel. When
there is only tpdm trace hw in the HW block, tpdm will connect to
tpda directly.
+---------------+ +-------------+
| tpdm@6c08000 | |tpdm@684C000 |
+-------|-------+ +------|------+
| |
+-------|-------+ |
| funnel@6c0b000| |
+-------|-------+ |
| |
+-------|-------+ |
|funnel@6c2d000 | |
+-------|-------+ |
| |
| +---------------+ |
+----- tpda@6004000 -----------+
+-------|-------+
|
+-------|-------+
|funnel@6005000 |
+---------------+
--8<--
Please could you add the above to a Documentation file (Of course
skip the description of patches).
Sure. I will add them to the Documentation file.
This patch series depends on patch series:
"[v5,00/14] coresight: Add new API to allocate trace source ID values"
https://patchwork.kernel.org/project/linux-arm-kernel/cover/20221101163103.17921-1-mike.leach@xxxxxxxxxx/
So, is there a strict binding between a TPDM and a TPDA ?
i.e., Multiple TPDMs could never end up reaching the sam
TPDA ? I see that the TPDMs could be connected to funnels
and thus other TPDMs could be connected to the same funnels
and thus reach the same TPDA.
There is no strict binding between TPDM and TPDA.
TPDA can have multiple TPDMs connect to it.
But There must be only one TPDA in the path from the TPDM source to
TMC sink.
TPDM can directly connect to TPDA's inport
or connect to funnel which will connect to TPDA's inport.
Also, the trace-id is bound to TPDA and not TPDM. So, if
we have multiple TPDMs, trace decoding is going to be
impossible.
The TPDMs which are connected to same TPDA shares the same
trace-id. When TPDA does packetization, different port will have
unique channel number for decoding.
So this assumes that nobody connects two TPDMs to a funnel, which
then connects to a TPDA ? (i.e. tpdm@684C000 above must not be
connected to funnel@6c0b000 or funnel@6c2d000).
In which case, two of them end up in the same port of the TPDA.
Suzuki