cxl/port: Record parent dport when adding ports

At the time that cxl_port instances are being created, cache the dport
from the parent port that points to this new child port. This will be
useful for region provisioning when walking the tree to calculate
decoder targets, and saves rewalking the dport list after the fact to
build this information.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20220624041950.559155-1-dan.j.williams@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 15 insertions, 12 deletions

diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 43b827b22bb2..0de6c1355393 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -526,7 +526,7 @@ static struct lock_class_key cxl_port_key;
 
 static struct cxl_port *cxl_port_alloc(struct device *uport,
 				       resource_size_t component_reg_phys,
-				       struct cxl_port *parent_port)
+				       struct cxl_dport *parent_dport)
 {
 	struct cxl_port *port;
 	struct device *dev;
@@ -549,11 +549,13 @@ static struct cxl_port *cxl_port_alloc(struct device *uport,
 	 * description.
 	 */
 	dev = &port->dev;
-	if (parent_port) {
+	if (parent_dport) {
+		struct cxl_port *parent_port = parent_dport->port;
 		struct cxl_port *iter;
 
 		dev->parent = &parent_port->dev;
 		port->depth = parent_port->depth + 1;
+		port->parent_dport = parent_dport;
 
 		/*
 		 * walk to the host bridge, or the first ancestor that knows
@@ -595,24 +597,24 @@ err:
  * @host: host device for devm operations
  * @uport: "physical" device implementing this upstream port
  * @component_reg_phys: (optional) for configurable cxl_port instances
- * @parent_port: next hop up in the CXL memory decode hierarchy
+ * @parent_dport: next hop up in the CXL memory decode hierarchy
  */
 struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport,
 				   resource_size_t component_reg_phys,
-				   struct cxl_port *parent_port)
+				   struct cxl_dport *parent_dport)
 {
 	struct cxl_port *port;
 	struct device *dev;
 	int rc;
 
-	port = cxl_port_alloc(uport, component_reg_phys, parent_port);
+	port = cxl_port_alloc(uport, component_reg_phys, parent_dport);
 	if (IS_ERR(port))
 		return port;
 
 	dev = &port->dev;
 	if (is_cxl_memdev(uport))
 		rc = dev_set_name(dev, "endpoint%d", port->id);
-	else if (parent_port)
+	else if (parent_dport)
 		rc = dev_set_name(dev, "port%d", port->id);
 	else
 		rc = dev_set_name(dev, "root%d", port->id);
@@ -1014,7 +1016,7 @@ static void delete_endpoint(void *data)
 	struct cxl_port *parent_port;
 	struct device *parent;
 
-	parent_port = cxl_mem_find_port(cxlmd);
+	parent_port = cxl_mem_find_port(cxlmd, NULL);
 	if (!parent_port)
 		goto out;
 	parent = &parent_port->dev;
@@ -1149,8 +1151,8 @@ static int add_port_attach_ep(struct cxl_memdev *cxlmd,
 {
 	struct device *dparent = grandparent(dport_dev);
 	struct cxl_port *port, *parent_port = NULL;
+	struct cxl_dport *dport, *parent_dport;
 	resource_size_t component_reg_phys;
-	struct cxl_dport *dport;
 	int rc;
 
 	if (!dparent) {
@@ -1164,7 +1166,7 @@ static int add_port_attach_ep(struct cxl_memdev *cxlmd,
 		return -ENXIO;
 	}
 
-	parent_port = find_cxl_port(dparent, NULL);
+	parent_port = find_cxl_port(dparent, &parent_dport);
 	if (!parent_port) {
 		/* iterate to create this parent_port */
 		return -EAGAIN;
@@ -1183,7 +1185,7 @@ static int add_port_attach_ep(struct cxl_memdev *cxlmd,
 	if (!port) {
 		component_reg_phys = find_component_registers(uport_dev);
 		port = devm_cxl_add_port(&parent_port->dev, uport_dev,
-					 component_reg_phys, parent_port);
+					 component_reg_phys, parent_dport);
 		/* retry find to pick up the new dport information */
 		if (!IS_ERR(port))
 			port = find_cxl_port_at(parent_port, dport_dev, &dport);
@@ -1290,9 +1292,10 @@ retry:
 }
 EXPORT_SYMBOL_NS_GPL(devm_cxl_enumerate_ports, CXL);
 
-struct cxl_port *cxl_mem_find_port(struct cxl_memdev *cxlmd)
+struct cxl_port *cxl_mem_find_port(struct cxl_memdev *cxlmd,
+				   struct cxl_dport **dport)
 {
-	return find_cxl_port(grandparent(&cxlmd->dev), NULL);
+	return find_cxl_port(grandparent(&cxlmd->dev), dport);
 }
 EXPORT_SYMBOL_NS_GPL(cxl_mem_find_port, CXL);