capability.
+What: /sys/bus/cxl/devices/{port,endpoint}X/parent_dport
+Date: January, 2023
+KernelVersion: v6.3
+Contact: linux-cxl@vger.kernel.org
+Description:
+ (RO) CXL port objects are instantiated for each upstream port in
+ a CXL/PCIe switch, and for each endpoint to map the
+ corresponding memory device into the CXL port hierarchy. When a
+ descendant CXL port (switch or endpoint) is enumerated it is
+ useful to know which 'dport' object in the parent CXL port
+ routes to this descendant. The 'parent_dport' symlink points to
+ the device representing the downstream port of a CXL switch that
+ routes to {port,endpoint}X.
+
+
What: /sys/bus/cxl/devices/portX/dportY
Date: June, 2021
KernelVersion: v5.14
return devm_add_action_or_reset(host, cxl_unlink_uport, port);
}
+static void cxl_unlink_parent_dport(void *_port)
+{
+ struct cxl_port *port = _port;
+
+ sysfs_remove_link(&port->dev.kobj, "parent_dport");
+}
+
+static int devm_cxl_link_parent_dport(struct device *host,
+ struct cxl_port *port,
+ struct cxl_dport *parent_dport)
+{
+ int rc;
+
+ if (!parent_dport)
+ return 0;
+
+ rc = sysfs_create_link(&port->dev.kobj, &parent_dport->dport->kobj,
+ "parent_dport");
+ if (rc)
+ return rc;
+ return devm_add_action_or_reset(host, cxl_unlink_parent_dport, port);
+}
+
static struct lock_class_key cxl_port_key;
static struct cxl_port *cxl_port_alloc(struct device *uport,
if (rc)
return ERR_PTR(rc);
+ rc = devm_cxl_link_parent_dport(host, port, parent_dport);
+ if (rc)
+ return ERR_PTR(rc);
+
return port;
err:
device_lock(parent);
if (parent->driver && !endpoint->dead) {
+ devm_release_action(parent, cxl_unlink_parent_dport, endpoint);
devm_release_action(parent, cxl_unlink_uport, endpoint);
devm_release_action(parent, unregister_port, endpoint);
}
*/
static void delete_switch_port(struct cxl_port *port)
{
+ devm_release_action(port->dev.parent, cxl_unlink_parent_dport, port);
devm_release_action(port->dev.parent, cxl_unlink_uport, port);
devm_release_action(port->dev.parent, unregister_port, port);
}