coresight: Add a helper for getting csdev->mode

Now that mode is in struct coresight_device accesses can be wrapped.

Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20240129154050.569566-12-james.clark@arm.com
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

coresight: Add explicit member initializers to coresight_dev_type

These could potentially become wrong silently if the enum is changed,
so explicitly initialize them.

Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20240129154050.569566-10-james.clark@arm.com
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

coresight: Remove atomic type from refcnt

Refcnt is only ever accessed from either inside the coresight_mutex, or
the device's spinlock, making the atomic type and atomic_dec_return()
calls confusing and unnecessary. The only point of synchronisation
outside of these two types of locks is already done with a compare and
swap on 'mode', which a comment has been added for.

There was one instance of refcnt being used outside of a lock in TPIU,
but that can easily be fixed by making it the same as all the other
devices and adding a spinlock. Potentially in the future all the
refcounting and locking can be moved up into the core code, and all the
mostly duplicate code from the individual devices can be removed.

Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20240129154050.569566-8-james.clark@arm.com
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

coresight: Move all sysfs code to sysfs file

At the moment the core file contains both sysfs functionality and
core functionality, while the Perf mode is in a separate file in
coresight-etm-perf.c

Many of the functions have ambiguous names like
coresight_enable_source() which actually only work in relation to the
sysfs mode. To avoid further confusion, move everything that isn't core
functionality into the sysfs file and append _sysfs to the ambiguous
functions.

Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20240129154050.569566-7-james.clark@arm.com
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

coresight: Fix CTI module refcount leak by making it a helper device

The CTI module has some hard coded refcounting code that has a leak.
For example running perf and then trying to unload it fails:

perf record -e cs_etm// -a -- ls
rmmod coresight_cti

rmmod: ERROR: Module coresight_cti is in use

The coresight core already handles references of devices in use, so by
making CTI a normal helper device, we get working refcounting for free.

Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230425143542.2305069-14-james.clark@arm.com

coresight: Store in-connections as well as out-connections

This will allow CATU to get its associated ETR in a generic way where
currently the enable path has some hard coded searches which avoid
the need to store input connections.

This also means that the full search for connected devices on removal
can be replaced with a loop through only the input and output devices.

Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230425143542.2305069-10-james.clark@arm.com

coresight: Rename connection members to make the direction explicit

When input connections are added they will use the same connection
object as the output so parent and child could be misinterpreted. Making
the direction unambiguous in the names should improve readability.

Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230425143542.2305069-6-james.clark@arm.com

coresight: Export global symbols

Export symbols used among coresight modules.

Tested-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>
Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200928163513.70169-6-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

coresight: Expose device connections via sysfs

Coresight device connections are a bit complicated and is not
exposed currently to the user. One has to look at the platform
descriptions (DT bindings or ACPI bindings) to make an understanding.
Given the new naming scheme, it will be helpful to have this information
to choose the appropriate devices for tracing. This patch exposes
the device connections via links in the sysfs directories.

e.g, for a connection devA[OutputPort_X] -> devB[InputPort_Y]
is represented as two symlinks:

/sys/bus/coresight/.../devA/out:X -> /sys/bus/coresight/.../devB
/sys/bus/coresight/.../devB/in:Y -> /sys/bus/coresight/.../devA

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
[Revised to use the generic sysfs links functions & link structures.
Provides a connections sysfs group in each device to hold the links.]
Co-developed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-5-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

coresight: Add generic sysfs link creation functions

To allow the connections between coresight components to be represented
in sysfs, generic methods for creating sysfs links between two coresight
devices are added.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-4-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>