1.. SPDX-License-Identifier: GPL-2.0 2 3============================= 4Coresight Dummy Trace Module 5============================= 6 7 :Author: Hao Zhang <quic_hazha@quicinc.com> 8 :Date: June 2023 9 10Introduction 11------------ 12 13The Coresight dummy trace module is for the specific devices that kernel don't 14have permission to access or configure, e.g., CoreSight TPDMs on Qualcomm 15platforms. For these devices, a dummy driver is needed to register them as 16Coresight devices. The module may also be used to define components that may 17not have any programming interfaces, so that paths can be created in the driver. 18It provides Coresight API for operations on dummy devices, such as enabling and 19disabling them. It also provides the Coresight dummy sink/source paths for 20debugging. 21 22Config details 23-------------- 24 25There are two types of nodes, dummy sink and dummy source. These nodes 26are available at ``/sys/bus/coresight/devices``. 27 28Example output:: 29 30 $ ls -l /sys/bus/coresight/devices | grep dummy 31 dummy_sink0 -> ../../../devices/platform/soc@0/soc@0:sink/dummy_sink0 32 dummy_source0 -> ../../../devices/platform/soc@0/soc@0:source/dummy_source0 33