Merge branch 'for-6.16/cxl-cleanups' into cxl-for-next

In preparation for code changes related to AMD Zen5 address translation
support, a number of small code refactor and cleanups are send ahead.

Author: davejiang

drivers/cxl/acpi.c

@@ -419,7 +419,15 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws,
 	rc = cxl_decoder_add(cxld, target_map);
 	if (rc)
 		return rc;
-	return cxl_root_decoder_autoremove(dev, no_free_ptr(cxlrd));
+
+	rc = cxl_root_decoder_autoremove(dev, no_free_ptr(cxlrd));
+	if (rc)
+		return rc;
+
+	dev_dbg(root_port->dev.parent, "%s added to %s\n",
+		dev_name(&cxld->dev), dev_name(&root_port->dev));
+
+	return 0;
 }
 
 static int cxl_parse_cfmws(union acpi_subtable_headers *header, void *arg,

drivers/cxl/core/cdat.c

@@ -28,7 +28,7 @@ static u32 cdat_normalize(u16 entry, u64 base, u8 type)
 	 */
 	if (entry == 0xffff || !entry)
 		return 0;
-	else if (base > (UINT_MAX / (entry)))
+	if (base > (UINT_MAX / (entry)))
 		return 0;
 
 	/*

drivers/cxl/core/hdm.c

@@ -34,7 +34,8 @@ static int add_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
 	if (rc)
 		return rc;
 
-	dev_dbg(&cxld->dev, "Added to port %s\n", dev_name(&port->dev));
+	dev_dbg(port->uport_dev, "%s added to %s\n",
+		dev_name(&cxld->dev), dev_name(&port->dev));
 
 	return 0;
 }

drivers/cxl/core/memdev.c

@@ -153,8 +153,8 @@ static ssize_t security_state_show(struct device *dev,
 		return sysfs_emit(buf, "frozen\n");
 	if (state & CXL_PMEM_SEC_STATE_LOCKED)
 		return sysfs_emit(buf, "locked\n");
-	else
-		return sysfs_emit(buf, "unlocked\n");
+
+	return sysfs_emit(buf, "unlocked\n");
 }
 static struct device_attribute dev_attr_security_state =
 	__ATTR(state, 0444, security_state_show, NULL);

drivers/cxl/core/pci.c

@@ -415,17 +415,20 @@ int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm,
 	 */
 	if (global_ctrl & CXL_HDM_DECODER_ENABLE || (!hdm && info->mem_enabled))
 		return devm_cxl_enable_mem(&port->dev, cxlds);
-	else if (!hdm)
-		return -ENODEV;
 
-	root = to_cxl_port(port->dev.parent);
-	while (!is_cxl_root(root) && is_cxl_port(root->dev.parent))
-		root = to_cxl_port(root->dev.parent);
-	if (!is_cxl_root(root)) {
-		dev_err(dev, "Failed to acquire root port for HDM enable\n");
+	/*
+	 * If the HDM Decoder Capability does not exist and DVSEC was
+	 * not setup, the DVSEC based emulation cannot be used.
+	 */
+	if (!hdm)
 		return -ENODEV;
-	}
 
+	/* The HDM Decoder Capability exists but is globally disabled. */
+
+	/*
+	 * If the DVSEC CXL Range registers are not enabled, just
+	 * enable and use the HDM Decoder Capability registers.
+	 */
 	if (!info->mem_enabled) {
 		rc = devm_cxl_enable_hdm(&port->dev, cxlhdm);
 		if (rc)
@@ -434,6 +437,26 @@ int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm,
 		return devm_cxl_enable_mem(&port->dev, cxlds);
 	}
 
+	/*
+	 * Per CXL 2.0 Section 8.1.3.8.3 and 8.1.3.8.4 DVSEC CXL Range 1 Base
+	 * [High,Low] when HDM operation is enabled the range register values
+	 * are ignored by the device, but the spec also recommends matching the
+	 * DVSEC Range 1,2 to HDM Decoder Range 0,1. So, non-zero info->ranges
+	 * are expected even though Linux does not require or maintain that
+	 * match. Check if at least one DVSEC range is enabled and allowed by
+	 * the platform. That is, the DVSEC range must be covered by a locked
+	 * platform window (CFMWS). Fail otherwise as the endpoint's decoders
+	 * cannot be used.
+	 */
+
+	root = to_cxl_port(port->dev.parent);
+	while (!is_cxl_root(root) && is_cxl_port(root->dev.parent))
+		root = to_cxl_port(root->dev.parent);
+	if (!is_cxl_root(root)) {
+		dev_err(dev, "Failed to acquire root port for HDM enable\n");
+		return -ENODEV;
+	}
+
 	for (i = 0, allowed = 0; i < info->ranges; i++) {
 		struct device *cxld_dev;
 
@@ -453,15 +476,6 @@ int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm,
 		return -ENXIO;
 	}
 
-	/*
-	 * Per CXL 2.0 Section 8.1.3.8.3 and 8.1.3.8.4 DVSEC CXL Range 1 Base
-	 * [High,Low] when HDM operation is enabled the range register values
-	 * are ignored by the device, but the spec also recommends matching the
-	 * DVSEC Range 1,2 to HDM Decoder Range 0,1. So, non-zero info->ranges
-	 * are expected even though Linux does not require or maintain that
-	 * match. If at least one DVSEC range is enabled and allowed, skip HDM
-	 * Decoder Capability Enable.
-	 */
 	return 0;
 }
 EXPORT_SYMBOL_NS_GPL(cxl_hdm_decode_init, "CXL");

drivers/cxl/core/port.c

@@ -602,17 +602,19 @@ struct cxl_port *to_cxl_port(const struct device *dev)
 }
 EXPORT_SYMBOL_NS_GPL(to_cxl_port, "CXL");
 
+struct cxl_port *parent_port_of(struct cxl_port *port)
+{
+	if (!port || !port->parent_dport)
+		return NULL;
+	return port->parent_dport->port;
+}
+
 static void unregister_port(void *_port)
 {
 	struct cxl_port *port = _port;
-	struct cxl_port *parent;
+	struct cxl_port *parent = parent_port_of(port);
 	struct device *lock_dev;
 
-	if (is_cxl_root(port))
-		parent = NULL;
-	else
-		parent = to_cxl_port(port->dev.parent);
-
 	/*
 	 * CXL root port's and the first level of ports are unregistered
 	 * under the platform firmware device lock, all other ports are
@@ -1035,15 +1037,6 @@ struct cxl_root *find_cxl_root(struct cxl_port *port)
 }
 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;