coresight: Use fwnode handle instead of device names

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>

1 files changed, 10 insertions, 4 deletions

diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
index 4394095ad224..49112a58478e 100644
--- a/drivers/hwtracing/coresight/coresight-platform.c
+++ b/drivers/hwtracing/coresight/coresight-platform.c
@@ -36,7 +36,7 @@ static int coresight_alloc_conns(struct device *dev,
 	return 0;
 }
 
-static int coresight_device_fwnode_match(struct device *dev, void *fwnode)
+int coresight_device_fwnode_match(struct device *dev, void *fwnode)
 {
 	return dev_fwnode(dev) == fwnode;
 }
@@ -219,9 +219,15 @@ static int of_coresight_parse_endpoint(struct device *dev,
 		}
 
 		conn->outport = endpoint.port;
-		conn->child_name = devm_kstrdup(dev,
-						dev_name(rdev),
-						GFP_KERNEL);
+		/*
+		 * Hold the refcount to the target device. This could be
+		 * released via:
+		 * 1) coresight_release_platform_data() if the probe fails or
+		 *    this device is unregistered.
+		 * 2) While removing the target device via
+		 *    coresight_remove_match()
+		 */
+		conn->child_fwnode = fwnode_handle_get(rdev_fwnode);
 		conn->child_port = rendpoint.port;
 		/* Connection record updated */
 		ret = 1;