Merge branch 'for-7.0/cxl-aer-prep' into cxl-for-next

Fixup and refactor downstream port enumeration to prepare for CXL port
protocol error handling. Main motivation is to move endpoint
component register mapping to a port object.

cxl/port: Unify endpoint and switch port lookup
cxl/port: Move endpoint component register management to cxl_port
cxl/port: Map Port RAS registers
cxl/port: Move dport RAS setup to dport add time
cxl/port: Move dport probe operations to a driver event
cxl/port: Move decoder setup before dport creation
cxl/port: Cleanup dport removal with a devres group
cxl/port: Reduce number of @DPORT variables in cxl_port_add_dport()
cxl/port: Cleanup handling of the nr_dports 0 -> 1 transition

Author: davejiang

drivers/cxl/core/core.h

@@ -144,6 +144,14 @@ int cxl_pci_get_bandwidth(struct pci_dev *pdev, struct access_coordinate *c);
 int cxl_port_get_switch_dport_bandwidth(struct cxl_port *port,
 					struct access_coordinate *c);
 
+static inline struct device *dport_to_host(struct cxl_dport *dport)
+{
+	struct cxl_port *port = dport->port;
+
+	if (is_cxl_root(port))
+		return port->uport_dev;
+	return &port->dev;
+}
 #ifdef CONFIG_CXL_RAS
 int cxl_ras_init(void);
 void cxl_ras_exit(void);
@@ -152,6 +160,7 @@ void cxl_handle_cor_ras(struct device *dev, void __iomem *ras_base);
 void cxl_dport_map_rch_aer(struct cxl_dport *dport);
 void cxl_disable_rch_root_ints(struct cxl_dport *dport);
 void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds);
+void devm_cxl_dport_ras_setup(struct cxl_dport *dport);
 #else
 static inline int cxl_ras_init(void)
 {
@@ -166,6 +175,7 @@ static inline void cxl_handle_cor_ras(struct device *dev, void __iomem *ras_base
 static inline void cxl_dport_map_rch_aer(struct cxl_dport *dport) { }
 static inline void cxl_disable_rch_root_ints(struct cxl_dport *dport) { }
 static inline void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds) { }
+static inline void devm_cxl_dport_ras_setup(struct cxl_dport *dport) { }
 #endif /* CONFIG_CXL_RAS */
 
 int cxl_gpf_port_setup(struct cxl_dport *dport);

drivers/cxl/core/hdm.c

@@ -1218,12 +1218,12 @@ static int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm,
 }
 
 /**
- * __devm_cxl_switch_port_decoders_setup - allocate and setup switch decoders
+ * devm_cxl_switch_port_decoders_setup - allocate and setup switch decoders
  * @port: CXL port context
  *
  * Return 0 or -errno on error
  */
-int __devm_cxl_switch_port_decoders_setup(struct cxl_port *port)
+int devm_cxl_switch_port_decoders_setup(struct cxl_port *port)
 {
 	struct cxl_hdm *cxlhdm;
 
@@ -1247,7 +1247,7 @@ int __devm_cxl_switch_port_decoders_setup(struct cxl_port *port)
 	dev_err(&port->dev, "HDM decoder capability not found\n");
 	return -ENXIO;
 }
-EXPORT_SYMBOL_NS_GPL(__devm_cxl_switch_port_decoders_setup, "CXL");
+EXPORT_SYMBOL_NS_GPL(devm_cxl_switch_port_decoders_setup, "CXL");
 
 /**
  * devm_cxl_endpoint_decoders_setup - allocate and setup endpoint decoders

drivers/cxl/core/pci.c

@@ -41,14 +41,14 @@ static int pci_get_port_num(struct pci_dev *pdev)
 }
 
 /**
- * __devm_cxl_add_dport_by_dev - allocate a dport by dport device
+ * devm_cxl_add_dport_by_dev - allocate a dport by dport device
  * @port: cxl_port that hosts the dport
  * @dport_dev: 'struct device' of the dport
  *
  * Returns the allocated dport on success or ERR_PTR() of -errno on error
  */
-struct cxl_dport *__devm_cxl_add_dport_by_dev(struct cxl_port *port,
-					      struct device *dport_dev)
+struct cxl_dport *devm_cxl_add_dport_by_dev(struct cxl_port *port,
+					    struct device *dport_dev)
 {
 	struct cxl_register_map map;
 	struct pci_dev *pdev;
@@ -69,7 +69,7 @@ struct cxl_dport *__devm_cxl_add_dport_by_dev(struct cxl_port *port,
 	device_lock_assert(&port->dev);
 	return devm_cxl_add_dport(port, dport_dev, port_num, map.resource);
 }
-EXPORT_SYMBOL_NS_GPL(__devm_cxl_add_dport_by_dev, "CXL");
+EXPORT_SYMBOL_NS_GPL(devm_cxl_add_dport_by_dev, "CXL");
 
 static int cxl_dvsec_mem_range_valid(struct cxl_dev_state *cxlds, int id)
 {

drivers/cxl/core/port.c

@@ -778,14 +778,15 @@ static int cxl_setup_comp_regs(struct device *host, struct cxl_register_map *map
 	return cxl_setup_regs(map);
 }
 
-static int cxl_port_setup_regs(struct cxl_port *port,
+int cxl_port_setup_regs(struct cxl_port *port,
 			resource_size_t component_reg_phys)
 {
 	if (dev_is_platform(port->uport_dev))
 		return 0;
 	return cxl_setup_comp_regs(&port->dev, &port->reg_map,
 				   component_reg_phys);
 }
+EXPORT_SYMBOL_NS_GPL(cxl_port_setup_regs, "CXL");
 
 static int cxl_dport_setup_regs(struct device *host, struct cxl_dport *dport,
 				resource_size_t component_reg_phys)
@@ -1068,11 +1069,15 @@ static int add_dport(struct cxl_port *port, struct cxl_dport *dport)
 		return -EBUSY;
 	}
 
+	/* Arrange for dport_dev to be valid through remove_dport() */
+	struct device *dev __free(put_device) = get_device(dport->dport_dev);
+
 	rc = xa_insert(&port->dports, (unsigned long)dport->dport_dev, dport,
 		       GFP_KERNEL);
 	if (rc)
 		return rc;
 
+	retain_and_null_ptr(dev);
 	port->nr_dports++;
 	return 0;
 }
@@ -1101,6 +1106,7 @@ static void cxl_dport_remove(void *data)
 	struct cxl_dport *dport = data;
 	struct cxl_port *port = dport->port;
 
+	port->nr_dports--;
 	xa_erase(&port->dports, (unsigned long) dport->dport_dev);
 	put_device(dport->dport_dev);
 }
@@ -1115,6 +1121,48 @@ static void cxl_dport_unlink(void *data)
 	sysfs_remove_link(&port->dev.kobj, link_name);
 }
 
+static void free_dport(void *dport)
+{
+	kfree(dport);
+}
+
+/*
+ * Upon return either a group is established with one action (free_dport()), or
+ * no group established and @dport is freed.
+ */
+static void *cxl_dport_open_dr_group_or_free(struct cxl_dport *dport)
+{
+	int rc;
+	struct device *host = dport_to_host(dport);
+	void *group = devres_open_group(host, dport, GFP_KERNEL);
+
+	if (!group) {
+		kfree(dport);
+		return NULL;
+	}
+
+	rc = devm_add_action_or_reset(host, free_dport, dport);
+	if (rc) {
+		devres_release_group(host, group);
+		return NULL;
+	}
+
+	return group;
+}
+
+static void cxl_dport_close_dr_group(struct cxl_dport *dport, void *group)
+{
+	devres_close_group(dport_to_host(dport), group);
+}
+
+static void del_dport(struct cxl_dport *dport)
+{
+	devres_release_group(dport_to_host(dport), dport);
+}
+
+/* The dport group id is the dport */
+DEFINE_FREE(cxl_dport_release_dr_group, void *, if (_T) del_dport(_T))
+
 static struct cxl_dport *
 __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
 		     int port_id, resource_size_t component_reg_phys,
@@ -1140,14 +1188,20 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
 	    CXL_TARGET_STRLEN)
 		return ERR_PTR(-EINVAL);
 
-	dport = devm_kzalloc(host, sizeof(*dport), GFP_KERNEL);
+	dport = kzalloc(sizeof(*dport), GFP_KERNEL);
 	if (!dport)
 		return ERR_PTR(-ENOMEM);
 
+	/* Just enough init to manage the devres group */
 	dport->dport_dev = dport_dev;
 	dport->port_id = port_id;
 	dport->port = port;
 
+	void *dport_dr_group __free(cxl_dport_release_dr_group) =
+		cxl_dport_open_dr_group_or_free(dport);
+	if (!dport_dr_group)
+		return ERR_PTR(-ENOMEM);
+
 	if (rcrb == CXL_RESOURCE_NONE) {
 		rc = cxl_dport_setup_regs(&port->dev, dport,
 					  component_reg_phys);
@@ -1183,21 +1237,6 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
 	if (rc)
 		return ERR_PTR(rc);
 
-	/*
-	 * Setup port register if this is the first dport showed up. Having
-	 * a dport also means that there is at least 1 active link.
-	 */
-	if (port->nr_dports == 1 &&
-	    port->component_reg_phys != CXL_RESOURCE_NONE) {
-		rc = cxl_port_setup_regs(port, port->component_reg_phys);
-		if (rc) {
-			xa_erase(&port->dports, (unsigned long)dport->dport_dev);
-			return ERR_PTR(rc);
-		}
-		port->component_reg_phys = CXL_RESOURCE_NONE;
-	}
-
-	get_device(dport_dev);
 	rc = devm_add_action_or_reset(host, cxl_dport_remove, dport);
 	if (rc)
 		return ERR_PTR(rc);
@@ -1215,6 +1254,12 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
 
 	cxl_debugfs_create_dport_dir(dport);
 
+	if (!dport->rch)
+		devm_cxl_dport_ras_setup(dport);
+
+	/* keep the group, and mark the end of devm actions */
+	cxl_dport_close_dr_group(dport, no_free_ptr(dport_dr_group));
+
 	return dport;
 }
 
@@ -1441,15 +1486,6 @@ static void delete_switch_port(struct cxl_port *port)
 	devm_release_action(port->dev.parent, unregister_port, port);
 }
 
-static void del_dport(struct cxl_dport *dport)
-{
-	struct cxl_port *port = dport->port;
-
-	devm_release_action(&port->dev, cxl_dport_unlink, dport);
-	devm_release_action(&port->dev, cxl_dport_remove, dport);
-	devm_kfree(&port->dev, dport);
-}
-
 static void del_dports(struct cxl_port *port)
 {
 	struct cxl_dport *dport;
@@ -1556,10 +1592,20 @@ static int match_port_by_uport(struct device *dev, const void *data)
 		return 0;
 
 	port = to_cxl_port(dev);
+	/* Endpoint ports are hosted by memdevs */
+	if (is_cxl_memdev(port->uport_dev))
+		return uport_dev == port->uport_dev->parent;
 	return uport_dev == port->uport_dev;
 }
 
-/*
+/**
+ * find_cxl_port_by_uport - Find a CXL port device companion
+ * @uport_dev: Device that acts as a switch or endpoint in the CXL hierarchy
+ *
+ * In the case of endpoint ports recall that port->uport_dev points to a 'struct
+ * cxl_memdev' device. So, the @uport_dev argument is the parent device of the
+ * 'struct cxl_memdev' in that case.
+ *
  * Function takes a device reference on the port device. Caller should do a
  * put_device() when done.
  */
@@ -1599,47 +1645,44 @@ static int update_decoder_targets(struct device *dev, void *data)
 	return 0;
 }
 
-DEFINE_FREE(del_cxl_dport, struct cxl_dport *, if (!IS_ERR_OR_NULL(_T)) del_dport(_T))
-static struct cxl_dport *cxl_port_add_dport(struct cxl_port *port,
-					    struct device *dport_dev)
+void cxl_port_update_decoder_targets(struct cxl_port *port,
+				     struct cxl_dport *dport)
 {
-	struct cxl_dport *dport;
-	int rc;
+	device_for_each_child(&port->dev, dport, update_decoder_targets);
+}
+EXPORT_SYMBOL_NS_GPL(cxl_port_update_decoder_targets, "CXL");
 
-	device_lock_assert(&port->dev);
-	if (!port->dev.driver)
-		return ERR_PTR(-ENXIO);
+static bool dport_exists(struct cxl_port *port, struct device *dport_dev)
+{
+	struct cxl_dport *dport = cxl_find_dport_by_dev(port, dport_dev);
 
-	dport = cxl_find_dport_by_dev(port, dport_dev);
 	if (dport) {
 		dev_dbg(&port->dev, "dport%d:%s already exists\n",
 			dport->port_id, dev_name(dport_dev));
-		return ERR_PTR(-EBUSY);
+		return true;
 	}
 
-	struct cxl_dport *new_dport __free(del_cxl_dport) =
-		devm_cxl_add_dport_by_dev(port, dport_dev);
-	if (IS_ERR(new_dport))
-		return new_dport;
+	return false;
+}
 
-	cxl_switch_parse_cdat(new_dport);
+static struct cxl_dport *probe_dport(struct cxl_port *port,
+				     struct device *dport_dev)
+{
+	struct cxl_driver *drv;
 
-	if (ida_is_empty(&port->decoder_ida)) {
-		rc = devm_cxl_switch_port_decoders_setup(port);
-		if (rc)
-			return ERR_PTR(rc);
-		dev_dbg(&port->dev, "first dport%d:%s added with decoders\n",
-			new_dport->port_id, dev_name(dport_dev));
-		return no_free_ptr(new_dport);
-	}
+	device_lock_assert(&port->dev);
+	if (!port->dev.driver)
+		return ERR_PTR(-ENXIO);
 
-	/* New dport added, update the decoder targets */
-	device_for_each_child(&port->dev, new_dport, update_decoder_targets);
+	if (dport_exists(port, dport_dev))
+		return ERR_PTR(-EBUSY);
 
-	dev_dbg(&port->dev, "dport%d:%s added\n", new_dport->port_id,
-		dev_name(dport_dev));
+	drv = container_of(port->dev.driver, struct cxl_driver, drv);
+	if (!drv->add_dport)
+		return ERR_PTR(-ENXIO);
 
-	return no_free_ptr(new_dport);
+	/* see cxl_port_add_dport() */
+	return drv->add_dport(port, dport_dev);
 }
 
 static struct cxl_dport *devm_cxl_create_port(struct device *ep_dev,
@@ -1686,7 +1729,7 @@ static struct cxl_dport *devm_cxl_create_port(struct device *ep_dev,
 	}
 
 	guard(device)(&port->dev);
-	return cxl_port_add_dport(port, dport_dev);
+	return probe_dport(port, dport_dev);
 }
 
 static int add_port_attach_ep(struct cxl_memdev *cxlmd,
@@ -1718,7 +1761,7 @@ static int add_port_attach_ep(struct cxl_memdev *cxlmd,
 	scoped_guard(device, &parent_port->dev) {
 		parent_dport = cxl_find_dport_by_dev(parent_port, dparent);
 		if (!parent_dport) {
-			parent_dport = cxl_port_add_dport(parent_port, dparent);
+			parent_dport = probe_dport(parent_port, dparent);
 			if (IS_ERR(parent_dport))
 				return PTR_ERR(parent_dport);
 		}
@@ -1754,7 +1797,7 @@ static struct cxl_dport *find_or_add_dport(struct cxl_port *port,
 	device_lock_assert(&port->dev);
 	dport = cxl_find_dport_by_dev(port, dport_dev);
 	if (!dport) {
-		dport = cxl_port_add_dport(port, dport_dev);
+		dport = probe_dport(port, dport_dev);
 		if (IS_ERR(dport))
 			return dport;