1 files changed, 139 insertions, 28 deletions

diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index b7c93bb18f6e..e59d9d37aa65 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -9,6 +9,7 @@
 #include <linux/pci.h>
 #include <linux/slab.h>
 #include <linux/idr.h>
+#include <linux/node.h>
 #include <cxlmem.h>
 #include <cxlpci.h>
 #include <cxl.h>
@@ -172,14 +173,10 @@ static ssize_t target_list_show(struct device *dev,
 {
 	struct cxl_switch_decoder *cxlsd = to_cxl_switch_decoder(dev);
 	ssize_t offset;
-	unsigned int seq;
 	int rc;
 
-	do {
-		seq = read_seqbegin(&cxlsd->target_lock);
-		rc = emit_target_list(cxlsd, buf);
-	} while (read_seqretry(&cxlsd->target_lock, seq));
-
+	guard(rwsem_read)(&cxl_region_rwsem);
+	rc = emit_target_list(cxlsd, buf);
 	if (rc < 0)
 		return rc;
 	offset = rc;
@@ -541,7 +538,10 @@ static void cxl_port_release(struct device *dev)
 	xa_destroy(&port->dports);
 	xa_destroy(&port->regions);
 	ida_free(&cxl_port_ida, port->id);
-	kfree(port);
+	if (is_cxl_root(port))
+		kfree(to_cxl_root(port));
+	else
+		kfree(port);
 }
 
 static ssize_t decoders_committed_show(struct device *dev,
@@ -669,17 +669,31 @@ static struct lock_class_key cxl_port_key;
 static struct cxl_port *cxl_port_alloc(struct device *uport_dev,
 				       struct cxl_dport *parent_dport)
 {
-	struct cxl_port *port;
+	struct cxl_root *cxl_root __free(kfree) = NULL;
+	struct cxl_port *port, *_port __free(kfree) = NULL;
 	struct device *dev;
 	int rc;
 
-	port = kzalloc(sizeof(*port), GFP_KERNEL);
-	if (!port)
-		return ERR_PTR(-ENOMEM);
+	/* No parent_dport, root cxl_port */
+	if (!parent_dport) {
+		cxl_root = kzalloc(sizeof(*cxl_root), GFP_KERNEL);
+		if (!cxl_root)
+			return ERR_PTR(-ENOMEM);
+	} else {
+		_port = kzalloc(sizeof(*port), GFP_KERNEL);
+		if (!_port)
+			return ERR_PTR(-ENOMEM);
+	}
 
 	rc = ida_alloc(&cxl_port_ida, GFP_KERNEL);
 	if (rc < 0)
-		goto err;
+		return ERR_PTR(rc);
+
+	if (cxl_root)
+		port = &no_free_ptr(cxl_root)->port;
+	else
+		port = no_free_ptr(_port);
+
 	port->id = rc;
 	port->uport_dev = uport_dev;
 
@@ -731,10 +745,6 @@ static struct cxl_port *cxl_port_alloc(struct device *uport_dev,
 	dev->type = &cxl_port_type;
 
 	return port;
-
-err:
-	kfree(port);
-	return ERR_PTR(rc);
 }
 
 static int cxl_setup_comp_regs(struct device *host, struct cxl_register_map *map,
@@ -841,6 +851,9 @@ static struct cxl_port *__devm_cxl_add_port(struct device *host,
 	if (rc)
 		return ERR_PTR(rc);
 
+	if (parent_dport && dev_is_pci(uport_dev))
+		port->pci_latency = cxl_pci_get_latency(to_pci_dev(uport_dev));
+
 	return port;
 
 err:
@@ -884,6 +897,22 @@ struct cxl_port *devm_cxl_add_port(struct device *host,
 }
 EXPORT_SYMBOL_NS_GPL(devm_cxl_add_port, CXL);
 
+struct cxl_root *devm_cxl_add_root(struct device *host,
+				   const struct cxl_root_ops *ops)
+{
+	struct cxl_root *cxl_root;
+	struct cxl_port *port;
+
+	port = devm_cxl_add_port(host, host, CXL_RESOURCE_NONE, NULL);
+	if (IS_ERR(port))
+		return (struct cxl_root *)port;
+
+	cxl_root = to_cxl_root(port);
+	cxl_root->ops = ops;
+	return cxl_root;
+}
+EXPORT_SYMBOL_NS_GPL(devm_cxl_add_root, CXL);
+
 struct pci_bus *cxl_port_to_pci_bus(struct cxl_port *port)
 {
 	/* There is no pci_bus associated with a CXL platform-root port */
@@ -939,7 +968,7 @@ static bool dev_is_cxl_root_child(struct device *dev)
 	return false;
 }
 
-struct cxl_port *find_cxl_root(struct cxl_port *port)
+struct cxl_root *find_cxl_root(struct cxl_port *port)
 {
 	struct cxl_port *iter = port;
 
@@ -949,10 +978,19 @@ struct cxl_port *find_cxl_root(struct cxl_port *port)
 	if (!iter)
 		return NULL;
 	get_device(&iter->dev);
-	return iter;
+	return to_cxl_root(iter);
 }
 EXPORT_SYMBOL_NS_GPL(find_cxl_root, CXL);
 
+void put_cxl_root(struct cxl_root *cxl_root)
+{
+	if (!cxl_root)
+		return;
+
+	put_device(&cxl_root->port.dev);
+}
+EXPORT_SYMBOL_NS_GPL(put_cxl_root, CXL);
+
 static struct cxl_dport *find_dport(struct cxl_port *port, int id)
 {
 	struct cxl_dport *dport;
@@ -1108,6 +1146,9 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
 	if (rc)
 		return ERR_PTR(rc);
 
+	if (dev_is_pci(dport_dev))
+		dport->link_latency = cxl_pci_get_latency(to_pci_dev(dport_dev));
+
 	return dport;
 }
 
@@ -1633,7 +1674,7 @@ EXPORT_SYMBOL_NS_GPL(cxl_mem_find_port, CXL);
 static int decoder_populate_targets(struct cxl_switch_decoder *cxlsd,
 				    struct cxl_port *port, int *target_map)
 {
-	int i, rc = 0;
+	int i;
 
 	if (!target_map)
 		return 0;
@@ -1643,19 +1684,16 @@ static int decoder_populate_targets(struct cxl_switch_decoder *cxlsd,
 	if (xa_empty(&port->dports))
 		return -EINVAL;
 
-	write_seqlock(&cxlsd->target_lock);
-	for (i = 0; i < cxlsd->nr_targets; i++) {
+	guard(rwsem_write)(&cxl_region_rwsem);
+	for (i = 0; i < cxlsd->cxld.interleave_ways; i++) {
 		struct cxl_dport *dport = find_dport(port, target_map[i]);
 
-		if (!dport) {
-			rc = -ENXIO;
-			break;
-		}
+		if (!dport)
+			return -ENXIO;
 		cxlsd->target[i] = dport;
 	}
-	write_sequnlock(&cxlsd->target_lock);
 
-	return rc;
+	return 0;
 }
 
 struct cxl_dport *cxl_hb_modulo(struct cxl_root_decoder *cxlrd, int pos)
@@ -1725,7 +1763,6 @@ static int cxl_switch_decoder_init(struct cxl_port *port,
 		return -EINVAL;
 
 	cxlsd->nr_targets = nr_targets;
-	seqlock_init(&cxlsd->target_lock);
 	return cxl_decoder_init(port, &cxlsd->cxld);
 }
 
@@ -2059,6 +2096,80 @@ bool schedule_cxl_memdev_detach(struct cxl_memdev *cxlmd)
 }
 EXPORT_SYMBOL_NS_GPL(schedule_cxl_memdev_detach, CXL);
 
+static void combine_coordinates(struct access_coordinate *c1,
+				struct access_coordinate *c2)
+{
+		if (c2->write_bandwidth)
+			c1->write_bandwidth = min(c1->write_bandwidth,
+						  c2->write_bandwidth);
+		c1->write_latency += c2->write_latency;
+
+		if (c2->read_bandwidth)
+			c1->read_bandwidth = min(c1->read_bandwidth,
+						 c2->read_bandwidth);
+		c1->read_latency += c2->read_latency;
+}
+
+/**
+ * cxl_endpoint_get_perf_coordinates - Retrieve performance numbers stored in dports
+ *				   of CXL path
+ * @port: endpoint cxl_port
+ * @coord: output performance data
+ *
+ * Return: errno on failure, 0 on success.
+ */
+int cxl_endpoint_get_perf_coordinates(struct cxl_port *port,
+				      struct access_coordinate *coord)
+{
+	struct access_coordinate c = {
+		.read_bandwidth = UINT_MAX,
+		.write_bandwidth = UINT_MAX,
+	};
+	struct cxl_port *iter = port;
+	struct cxl_dport *dport;
+	struct pci_dev *pdev;
+	unsigned int bw;
+
+	if (!is_cxl_endpoint(port))
+		return -EINVAL;
+
+	dport = iter->parent_dport;
+
+	/*
+	 * Exit the loop when the parent port of the current port is cxl root.
+	 * The iterative loop starts at the endpoint and gathers the
+	 * latency of the CXL link from the current iter to the next downstream
+	 * port each iteration. If the parent is cxl root then there is
+	 * nothing to gather.
+	 */
+	while (iter && !is_cxl_root(to_cxl_port(iter->dev.parent))) {
+		combine_coordinates(&c, &dport->sw_coord);
+		c.write_latency += dport->link_latency;
+		c.read_latency += dport->link_latency;
+
+		iter = to_cxl_port(iter->dev.parent);
+		dport = iter->parent_dport;
+	}
+
+	/* Augment with the generic port (host bridge) perf data */
+	combine_coordinates(&c, &dport->hb_coord);
+
+	/* Get the calculated PCI paths bandwidth */
+	pdev = to_pci_dev(port->uport_dev->parent);
+	bw = pcie_bandwidth_available(pdev, NULL, NULL, NULL);
+	if (bw == 0)
+		return -ENXIO;
+	bw /= BITS_PER_BYTE;
+
+	c.write_bandwidth = min(c.write_bandwidth, bw);
+	c.read_bandwidth = min(c.read_bandwidth, bw);
+
+	*coord = c;
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(cxl_endpoint_get_perf_coordinates, CXL);
+
 /* for user tooling to ensure port disable work has completed */
 static ssize_t flush_store(const struct bus_type *bus, const char *buf, size_t count)
 {