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>
This commit is contained in:
Suzuki K Poulose 2020-05-18 12:02:23 -06:00 committed by Greg Kroah-Hartman
parent 8096152588
commit 8a7365c2d4
4 changed files with 121 additions and 12 deletions

View file

@ -140,12 +140,14 @@ struct coresight_desc {
* @chid_fwnode: remote component's fwnode handle.
* @child_dev: a @coresight_device representation of the component
connected to @outport.
* @link: Representation of the connection as a sysfs link.
*/
struct coresight_connection {
int outport;
int child_port;
struct fwnode_handle *child_fwnode;
struct coresight_device *child_dev;
struct coresight_sysfs_link *link;
};
/**