So far we have reused the name of the "platform" device for
the CoreSight device. But this is not very intuitive when
we move to ACPI. Also, the ACPI device names have ":" in them
(e.g, ARMHC97C:01), which the perf tool doesn't like very much.
This patch introduces a generic naming scheme, givin more intuitive
names for the devices that appear on the CoreSight bus.
The names follow the pattern "prefix" followed by "index" (e.g, etm5).
We maintain a list of allocated devices per "prefix" to make sure
we don't allocate a new name when it is reprobed (e.g, due to
unsatisifed device dependencies). So, we maintain the list
of "fwnodes" of the parent devices to allocate a consistent name.
All devices except the ETMs get an index allocated in the order
of probing. ETMs get an index based on the CPU they are attached to.
TMC devices are named using "tmc_etf", "tmc_etb", and "tmc_etr"
prefixes depending on the configuration of the device.
The replicators and funnels are not classified as dynamic/static
anymore. One could easily figure that out by checking the presence
of "mgmt" registers under sysfs.
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We rely on the device names to find a CoreSight device on the
coresight bus. The device name however is obtained from the platform,
which is bound to the real platform/amba device. As we are about
to use different naming scheme for the coresight devices, we can't
rely on the platform device name to find the corresponding
coresight device. Instead we use the platform agnostic
"fwnode handle" of the parent device to find the devices.
We also reuse the same fwnode as the parent for the Coresight
device we create.
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The platform specific information describes the connections and
the ports of a given coresigh device. This information is also
recorded in the coresight device as separate fields. Let us reuse
the original platform description to streamline the handling
of the data.
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We are about to use a name independent of the parent AMBA device
name. As such, there is no need to have it in the platform description.
Let us move this to coresight description instead.
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CPU field is only used by ETMs and there is a separate API
for fetching the same. So, let us use that instead of using
the common platform probing helper. Also, remove it from the
platform_data.
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The CoreSight components ETM and CPU-Debug are always associated
with CPUs. Replace the of_coresight_get_cpu() with a platform
agnostic helper, in preparation to add ACPI support.
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
So far we have hard coded the DT platform parsing code in
every driver. Introduce generic helper to parse the information
provided by the firmware in a platform agnostic manner, in preparation
for the ACPI support.
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Make struct perf_event available to sink buffer allocation functions in
order to use the pid they carry to allocate and free buffer memory along
with regimenting access to what source a sink can collect data for.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Robert Walker <robert.walker@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In preparation to handle device reference counting inside of the sink
drivers, add a return code to the sink::disable() operation so that
proper action can be taken if a sink has not been disabled.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Tested-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Robert Walker <robert.walker@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a "sinks" directory entry so that users can see all the sinks
available in the system in a single place. Individual sink are added
as they are registered with the coresight bus.
Committer tests:
Test built on a ubuntu 18.04 container with a cross build environment to
arm64, the new field is there, need to find a machine with this feature
to do further testing in the future.
root@d15263e5734a:/git/perf# grep CORESIGHT /tmp/build/v5.0-rc2+/.config
CONFIG_CORESIGHT=y
CONFIG_CORESIGHT_LINKS_AND_SINKS=y
CONFIG_CORESIGHT_LINK_AND_SINK_TMC=y
CONFIG_CORESIGHT_CATU=y
CONFIG_CORESIGHT_SINK_TPIU=y
CONFIG_CORESIGHT_SINK_ETBV10=y
CONFIG_CORESIGHT_SOURCE_ETM4X=y
CONFIG_CORESIGHT_DYNAMIC_REPLICATOR=y
CONFIG_CORESIGHT_STM=y
CONFIG_CORESIGHT_CPU_DEBUG=m
root@d15263e5734a:/git/perf#
root@d15263e5734a:/git/perf# file /tmp/build/v5.0-rc2+/drivers/hwtracing/coresight/*.o
.../coresight/coresight-catu.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-cpu-debug.mod.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-cpu-debug.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-dynamic-replicator.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-etb10.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-etm-perf.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-etm4x-sysfs.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-etm4x.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-funnel.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-replicator.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-stm.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-tmc-etf.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-tmc-etr.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-tmc.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight-tpiu.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/coresight.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
.../coresight/of_coresight.o: ELF 64-bit MSB relocatable, ARM aarch64, version 1 (SYSV), not stripped
root@d15263e5734a:/git/perf#
root@d15263e5734a:/git/perf# pahole -C coresight_device /tmp/build/v5.0-rc2+/drivers/hwtracing/coresight/coresight.o
struct coresight_device {
struct coresight_connection * conns; /* 0 8 */
int nr_inport; /* 8 4 */
int nr_outport; /* 12 4 */
enum coresight_dev_type type; /* 16 4 */
union coresight_dev_subtype subtype; /* 20 8 */
/* XXX 4 bytes hole, try to pack */
const struct coresight_ops * ops; /* 32 8 */
struct device dev; /* 40 1408 */
/* XXX last struct has 7 bytes of padding */
/* --- cacheline 22 boundary (1408 bytes) was 40 bytes ago --- */
atomic_t * refcnt; /* 1448 8 */
bool orphan; /* 1456 1 */
bool enable; /* 1457 1 */
bool activated; /* 1458 1 */
/* XXX 5 bytes hole, try to pack */
struct dev_ext_attribute * ea; /* 1464 8 */
/* size: 1472, cachelines: 23, members: 12 */
/* sum members: 1463, holes: 2, sum holes: 9 */
/* paddings: 1, sum paddings: 7 */
};
root@d15263e5734a:/git/perf#
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Link: http://lkml.kernel.org/r/20190131184714.20388-3-mathieu.poirier@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Coresight architecture defines CLAIM tags for a device to negotiate
control of the components (external agent vs self-hosted). Each device
has a pair of registers (CLAIMSET & CLAIMCLR) for managing the CLAIM
tags. However, the protocol for the CLAIM tags is IMPLEMENTATION DEFINED.
PSCI has recommendations for the use of the CLAIM tags to negotiate
controls for external agent vs self-hosted use. This patch implements
the recommended protocol by PSCI.
The claim/disclaim operations are performed from the device specific
drivers. The disadvantage is that the calls are sprinkled in each driver,
but this makes the operation much simpler.
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In coresight perf mode, we need to prepare the sink before
starting a session, which is done via set_buffer call back.
We then proceed to enable the tracing. If we fail to start
the session successfully, we leave the sink configuration
unchanged. In order to make the operation atomic and to
avoid yet another call back to clear the buffer, we get
rid of the "set_buffer" call back and pass the buffer details
via enable() call back to the sink.
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Right now we issue an update_buffer() and reset_buffer() call backs
in succession when we stop tracing an event. The update_buffer is
supposed to check the status of the buffer and make sure the ring buffer
is updated with the trace data. And we store information about the
size of the data collected only to be consumed by the reset_buffer
callback which always follows the update_buffer. This was originally
designed for handling future IPs which could trigger a buffer overflow
interrupt. This patch gets rid of the reset_buffer callback altogether
and performs the actions in update_buffer, making it return the size
collected. We can always add the support for handling the overflow
interrupt case later.
This removes some not-so pretty hack (storing the new head in the
size field for snapshot mode) and cleans it up a little bit.
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The platform code parses the component connections and populates
a platform-description of the output connections in arrays of fields
(which is never freed). This is later copied in the coresight_register
to a newly allocated area, represented by coresight_connection(s).
This patch cleans up the code dealing with connections by making
use of the "coresight_connection" structure right at the platform
code and lets the generic driver simply re-use information provided
by the platform.
Thus making it reader friendly as well as avoiding the wastage of
unused memory.
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add the initial support for Coresight Address Translation Unit, which
augments the TMC in Coresight SoC-600 by providing an improved Scatter
Gather mechanism. CATU is always connected to a single TMC-ETR and
converts the AXI address with a translated address (from a given SG
table with specific format). The CATU should be programmed in pass
through mode and enabled even if the ETR doesn't use the translation
by CATU.
This patch provides mechanism to enable/disable the CATU always in the
pass through mode.
We reuse the existing ports mechanism to link the TMC-ETR to the
connected CATU.
i.e, TMC-ETR:output_port0 -> CATU:input_port0
Reference manual for CATU component is avilable in version r2p0 of :
"Arm Coresight System-on-Chip SoC-600 Technical Reference Manual".
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a new coresight device type, which do not belong to any
of the existing types, i.e, source, sink, link etc. A helper
device could be connected to a coresight device, which could
augment the functionality of the coresight device.
This is intended to cover Coresight Address Translation Unit (CATU)
devices, which provide improved Scatter Gather mechanism for TMC
ETR. The idea is that the helper device could be controlled by
the driver of the device it is attached to (in this case ETR),
transparent to the generic coresight driver (and paths).
The operations include enable(), disable(), both of which could
accept a device specific "data" which the driving device and
the helper device could share. Since they don't appear in the
coresight "path" tracked by software, we have to ensure that
they are powered up/down whenever the master device is turned
on.
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Clean up our struct a little bit by using a union instead of
a struct for tracking the subtype of a device.
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that we prevent users from using contextID tracing when PID namespaces
are involved there is no client for function coresight_vpid_to_pid(). As
such simply remove it.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Kim Phillips <kim.phillips@arm.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Moving all kernel side CoreSight framework and drivers to SPDX identifier.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is refactor to add function of_coresight_get_cpu(), so it's used to
retrieve CPU id for coresight component. Finally can use it as a common
function for multiple places.
Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Almost low level functions from open firmware have used const to
qualify device_node structures, so add const for device_node
parameters in of_coresight related functions.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In preparation for adding more flags to perf AUX records, introduce a
separate API for setting the flags for a session, rather than appending
more bool arguments to perf_aux_output_end. This allows to set each
flag at the time a corresponding condition is detected, instead of
tracking it in each driver's private state.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/20170220133352.17995-3-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With this commit [1] address range filter information is now found
in the struct hw_perf_event::addr_filters. As such pass the event
itself to the coresight_source::enable/disable() functions so that
both event attribute and filter can be accessible for configuration.
[1] 'commit 375637bc52 ("perf/core: Introduce address range filtering")'
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adding an ETB10 specific AUX area operations to be used
by the perf framework when events are initialised.
Part of this operation involves modeling the mmap'ed area
based on the specific ways a sink buffer gathers information.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adding an operation mode to the sink->enable() API in order
to prevent simultaneous access from different callers.
TPIU and TMC won't be supplemented with the AUX area
API immediately and as such ignore the new mode.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
That way traces can be enabled and disabled automatically
from the Perf subystem using the PMU abstraction.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adding a new mode to source API enable() in order to
distinguish where the request comes from. That way it is
possible to perform different operations based on where
the request was issued from.
The ETM4x driver is also modified to keep in sync with the
new interface.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When using the Coresight framework from the sysFS interface a
tracer is always handling a single session and as such, a path
can be associated with a tracer. But when supporting multiple
session per tracer there is no guarantee that sessions will always
have the same path from source to sink.
This patch is removing the automatic association between path and
tracers. The building of a path and enablement of the components
in the path are decoupled, allowing for the association of a path
with a session rather than a tracer.
To keep backward functionality with the current sysFS access methods
a per-cpu place holder is used to keep a handle on the path built when
tracers are enabled. Lastly APIs to build paths and enable tracers are
made public so that other subsystem can interact with the Coresight
framework.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Other than plainly parsing the device tree there is no way to
know which CPU a tracer is affined to. As such adding an
interface to lookup the CPU field enclosed in the etm_drvdata
structure that was initialised at boot time.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tracing gets enabled _for_ a source rather than _from_ a source.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The patch "Coresight: Add an interface for supporting ETM3/4 Context ID
tracing" adds uses of find_task_by_vpid() and task_pid_nr() from
linux/sched.h but does not include that header causing build errors in
at least an ARM allmodconfig where it is not implicitly included. Add an
explicit include to fix that.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If PID namespace is enabled, everytime users configure the Context ID
register to trace the specific process, there needs to be a translation
between the real PID seen from the kernel and VPID seen from the
namespace in which the user's process resides .
This patch just adds the translation interface for ETMs.
Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This function coresight_is_bit_set() isn't called, so we should
remove it.
Signed-off-by: Kaixu Xia <xiakaixu@huawei.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixing problem reported by:
https://lkml.org/lkml/2015/1/6/86
The #ifdef/#endif is wrong and prevents the stub of function
of_get_coresight_platform_data() from being visible when
CONFIG_OF is not defined.
Moving CONFIG_OF condition out of CONFIG_CORESIGHT, making
them both independent.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Debugfs isn't used for coresight configuration, so the macro
CORESIGHT_DEBUGFS_ENTRY is unnecessary, just remove it.
Signed-off-by: Xia Kaixu <xiakaixu@huawei.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fixes following minor issues in code comments in coresight.h
- typo %s/enpoint/endpoint
- alignment of comment section for struct coresight_desc
- correction of comment for struct coresight_connection and
struct coresight_device.
Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CoreSight components are compliant with the ARM CoreSight
architecture specification and can be connected in various
topologies to suit a particular SoC tracing needs. These trace
components can generally be classified as sources, links and
sinks. Trace data produced by one or more sources flows through
the intermediate links connecting the source to the currently
selected sink.
The CoreSight framework provides an interface for the CoreSight trace
drivers to register themselves with. It's intended to build up a
topological view of the CoreSight components and configure the
correct serie of components on user input via sysfs.
For eg., when enabling a source, the framework builds up a path
consisting of all the components connecting the source to the
currently selected sink(s) and enables all of them.
The framework also supports switching between available sinks
and provides status information to user space applications
through the debugfs interface.
Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
