trace/coresight/coresight-config.rst

1 .. SPDX-License-Identifier: GPL-2.0
14 programming of the CoreSight system with pre-defined configurations that
17 Many CoreSight components can be programmed in complex ways - especially ETMs.
30 --------
37 a matching device, either when the feature is loaded into the system, or when the
40 The load process involves interpreting the descriptor into a set of register
41 accesses in the driver - the resource usage and parameter descriptions
42 translated into appropriate register accesses. This interpretation makes it easy
47 will be programmed into the device hardware.
67 system - which is described below.
69 The current value of the parameter is loaded into the device when the feature
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82 enabled on a class of devices - i.e. any ETMv4, or specific devices, e.g. a
118     perf record -e cs_etm/autofdo/ myapp
125    In this case 'strobing' is enabled & programmed into the ETMv4.
136 The set of configurations and features that are currently loaded into the
139 Mount configfs as normal and the 'cs-syscfg' subsystem will appear::
142     cs-syscfg  stp-policy
144 This has two sub-directories::
146     $ cd cs-syscfg/
150 The system has the configuration 'autofdo' built in. It may be examined as
212 The configurations loaded into the CoreSight configuration management are
220 The key directory here is 'events' - a generic perf directory which allows
224 The entry in the 'events' directory uses perfs built in syntax generator
234     $ perf record -e cs_etm/autofdo/u --per-thread <application>
238     $ perf record -e cs_etm/autofdo,preset=1/u --per-thread <application>
256 This will then use any default parameter values in the features - which can be
264 The valid values for preset are 0 - to deselect presets, and any value of
265 <n> where a preset<n> sub-directory is present.
280 Custom configurations and / or features can be dynamically loaded into the
285 This creates a new configuration that uses the existing built in
289 file system and is selectable in the same way as the built in configuration