A DTSL configuration can contain several trace capture devices. The following
are some possible reasons for this:
- The target platform contains several CoreSight ETB components.
- The target platform can output to an external DSTREAM device, in addition to
an internal CoreSight ETB.
In some cases, there can only be one active trace capture device. In this case,
you can choose whether to use the DSTREAM or the ETB. In other cases, there can be
several trace capture devices active at the same time. This is common when the platform
contains multiple clusters of cores, each of which outputs trace to its own CoreSight
Figure 15-17 Example of Multiple Trace Capture Devices
To allow trace clients to receive trace data from a trace source, the DTSL
configuration can be told about the association between a trace source and one or more
trace capture devices. In the figure, for example, the trace source named PTM_2 is
associated with the trace capture device named ETB_1. If a client wants to display the
trace data for PTM_2, it can ask DTSL which trace capture devices are associated with
that trace source, and direct its trace read requests to the correct trace capture
NoteIt is possible for a trace source to be associated with multiple trace
capture devices, such as an internal ETB and an external DSTREAM. In such cases, you
might need to provide more information to the client about which trace capture device to
use when reading trace data.