Commit 7f8faf96 authored by Dan Williams's avatar Dan Williams
Browse files

cxl/mem: Enumerate port targets before adding endpoints 



The port scanning algorithm in devm_cxl_enumerate_ports() walks up the
topology and adds cxl_port objects starting from the root down to the
endpoint. When those ports are initially created they know all their
dports, but they do not know the downstream cxl_port instance that
represents the next descendant in the topology. Rework create_endpoint()
into devm_cxl_add_endpoint() that enumerates the downstream cxl_port
topology into each port's 'struct cxl_ep' record for each endpoint it
that the port is an ancestor.

Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20220624041950.559155-7-dan.j.williams@intel.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 538831f1

drivers/cxl/core/port.c

+41 −0
Original line number Diff line number Diff line
@@ -1087,6 +1087,47 @@ static struct cxl_ep *cxl_ep_load(struct cxl_port *port, 
	return xa_load(&port->endpoints, (unsigned long)&cxlmd->dev);

}



int devm_cxl_add_endpoint(struct cxl_memdev *cxlmd,

			  struct cxl_dport *parent_dport)

{

	struct cxl_port *parent_port = parent_dport->port;

	struct cxl_dev_state *cxlds = cxlmd->cxlds;

	struct cxl_port *endpoint, *iter, *down;

	int rc;



	/*

	 * Now that the path to the root is established record all the

	 * intervening ports in the chain.

	 */

	for (iter = parent_port, down = NULL; !is_cxl_root(iter);

	     down = iter, iter = to_cxl_port(iter->dev.parent)) {

		struct cxl_ep *ep;



		ep = cxl_ep_load(iter, cxlmd);

		ep->next = down;

	}



	endpoint = devm_cxl_add_port(&parent_port->dev, &cxlmd->dev,

				     cxlds->component_reg_phys, parent_dport);

	if (IS_ERR(endpoint))

		return PTR_ERR(endpoint);



	dev_dbg(&cxlmd->dev, "add: %s\n", dev_name(&endpoint->dev));



	rc = cxl_endpoint_autoremove(cxlmd, endpoint);

	if (rc)

		return rc;



	if (!endpoint->dev.driver) {

		dev_err(&cxlmd->dev, "%s failed probe\n",

			dev_name(&endpoint->dev));

		return -ENXIO;

	}



	return 0;

}

EXPORT_SYMBOL_NS_GPL(devm_cxl_add_endpoint, CXL);



static void cxl_detach_ep(void *data)

{

	struct cxl_memdev *cxlmd = data;

drivers/cxl/cxl.h

+5 −0
Original line number Diff line number Diff line
@@ -385,10 +385,13 @@ struct cxl_dport { 
 * struct cxl_ep - track an endpoint's interest in a port

 * @ep: device that hosts a generic CXL endpoint (expander or accelerator)

 * @dport: which dport routes to this endpoint on @port

 * @next: cxl switch port across the link attached to @dport NULL if

 *	  attached to an endpoint

 */

struct cxl_ep {

	struct device *ep;

	struct cxl_dport *dport;

	struct cxl_port *next;

};



/*
@@ -411,6 +414,8 @@ struct pci_bus *cxl_port_to_pci_bus(struct cxl_port *port); 
struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport,

				   resource_size_t component_reg_phys,

				   struct cxl_dport *parent_dport);

int devm_cxl_add_endpoint(struct cxl_memdev *cxlmd,

			  struct cxl_dport *parent_dport);

struct cxl_port *find_cxl_root(struct device *dev);

int devm_cxl_enumerate_ports(struct cxl_memdev *cxlmd);

int cxl_bus_rescan(void);

drivers/cxl/mem.c

+1 −29
Original line number Diff line number Diff line
@@ -25,34 +25,6 @@ 
 * in higher level operations.

 */



static int create_endpoint(struct cxl_memdev *cxlmd,

			   struct cxl_dport *parent_dport)

{

	struct cxl_port *parent_port = parent_dport->port;

	struct cxl_dev_state *cxlds = cxlmd->cxlds;

	struct cxl_port *endpoint;

	int rc;



	endpoint = devm_cxl_add_port(&parent_port->dev, &cxlmd->dev,

				     cxlds->component_reg_phys, parent_dport);

	if (IS_ERR(endpoint))

		return PTR_ERR(endpoint);



	dev_dbg(&cxlmd->dev, "add: %s\n", dev_name(&endpoint->dev));



	rc = cxl_endpoint_autoremove(cxlmd, endpoint);

	if (rc)

		return rc;



	if (!endpoint->dev.driver) {

		dev_err(&cxlmd->dev, "%s failed probe\n",

			dev_name(&endpoint->dev));

		return -ENXIO;

	}



	return 0;

}



static void enable_suspend(void *data)

{

	cxl_mem_active_dec();
@@ -116,7 +88,7 @@ static int cxl_mem_probe(struct device *dev) 
		goto unlock;

	}



	rc = create_endpoint(cxlmd, dport);

	rc = devm_cxl_add_endpoint(cxlmd, dport);

unlock:

	device_unlock(&parent_port->dev);

	put_device(&parent_port->dev);