Merge branch 'for-6.7/cxl-rch-eh' into cxl/next

Restricted CXL Host (RCH) Error Handling undoes the topology munging of
CXL 1.1 to enabled some AER recovery, and lands some base infrastructure
for handling Root-Complex-Event-Collectors (RCECs) with CXL. Include
this long running series finally for v6.7.

10 files changed, 406 insertions, 129 deletions

diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 8e5f3d84311e..86d7ba23235e 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -73,6 +73,7 @@ struct cxl_rcrb_info;
 resource_size_t __rcrb_to_component(struct device *dev,
 				    struct cxl_rcrb_info *ri,
 				    enum cxl_rcrb which);
+u16 cxl_rcrb_to_aer(struct device *dev, resource_size_t rcrb);
 
 extern struct rw_semaphore cxl_dpa_rwsem;
 extern struct rw_semaphore cxl_region_rwsem;
diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index 506c9e14cdf9..d3d338509d96 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -81,26 +81,6 @@ static void parse_hdm_decoder_caps(struct cxl_hdm *cxlhdm)
 		cxlhdm->interleave_mask |= GENMASK(14, 12);
 }
 
-static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb,
-				struct cxl_component_regs *regs)
-{
-	struct cxl_register_map map = {
-		.dev = &port->dev,
-		.resource = port->component_reg_phys,
-		.base = crb,
-		.max_size = CXL_COMPONENT_REG_BLOCK_SIZE,
-	};
-
-	cxl_probe_component_regs(&port->dev, crb, &map.component_map);
-	if (!map.component_map.hdm_decoder.valid) {
-		dev_dbg(&port->dev, "HDM decoder registers not implemented\n");
-		/* unique error code to indicate no HDM decoder capability */
-		return -ENODEV;
-	}
-
-	return cxl_map_component_regs(&map, regs, BIT(CXL_CM_CAP_CAP_ID_HDM));
-}
-
 static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)
 {
 	struct cxl_hdm *cxlhdm;
@@ -153,9 +133,9 @@ static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)
 struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port,
 				   struct cxl_endpoint_dvsec_info *info)
 {
+	struct cxl_register_map *reg_map = &port->reg_map;
 	struct device *dev = &port->dev;
 	struct cxl_hdm *cxlhdm;
-	void __iomem *crb;
 	int rc;
 
 	cxlhdm = devm_kzalloc(dev, sizeof(*cxlhdm), GFP_KERNEL);
@@ -164,19 +144,29 @@ struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port,
 	cxlhdm->port = port;
 	dev_set_drvdata(dev, cxlhdm);
 
-	crb = ioremap(port->component_reg_phys, CXL_COMPONENT_REG_BLOCK_SIZE);
-	if (!crb && info && info->mem_enabled) {
+	/* Memory devices can configure device HDM using DVSEC range regs. */
+	if (reg_map->resource == CXL_RESOURCE_NONE) {
+		if (!info && !info->mem_enabled) {
+			dev_err(dev, "No component registers mapped\n");
+			return ERR_PTR(-ENXIO);
+		}
+
 		cxlhdm->decoder_count = info->ranges;
 		return cxlhdm;
-	} else if (!crb) {
-		dev_err(dev, "No component registers mapped\n");
-		return ERR_PTR(-ENXIO);
 	}
 
-	rc = map_hdm_decoder_regs(port, crb, &cxlhdm->regs);
-	iounmap(crb);
-	if (rc)
+	if (!reg_map->component_map.hdm_decoder.valid) {
+		dev_dbg(&port->dev, "HDM decoder registers not implemented\n");
+		/* unique error code to indicate no HDM decoder capability */
+		return ERR_PTR(-ENODEV);
+	}
+
+	rc = cxl_map_component_regs(reg_map, &cxlhdm->regs,
+				    BIT(CXL_CM_CAP_CAP_ID_HDM));
+	if (rc) {
+		dev_err(dev, "Failed to map HDM capability.\n");
 		return ERR_PTR(rc);
+	}
 
 	parse_hdm_decoder_caps(cxlhdm);
 	if (cxlhdm->decoder_count == 0) {
diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index b91bb9886991..72ee522e747d 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -1402,6 +1402,8 @@ struct cxl_memdev_state *cxl_memdev_state_create(struct device *dev)
 	mutex_init(&mds->mbox_mutex);
 	mutex_init(&mds->event.log_lock);
 	mds->cxlds.dev = dev;
+	mds->cxlds.reg_map.host = dev;
+	mds->cxlds.reg_map.resource = CXL_RESOURCE_NONE;
 	mds->cxlds.type = CXL_DEVTYPE_CLASSMEM;
 
 	return mds;
diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index c7a7887ebdcf..3da195caa4ad 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -5,6 +5,7 @@
 #include <linux/delay.h>
 #include <linux/pci.h>
 #include <linux/pci-doe.h>
+#include <linux/aer.h>
 #include <cxlpci.h>
 #include <cxlmem.h>
 #include <cxl.h>
@@ -646,32 +647,36 @@ void read_cdat_data(struct cxl_port *port)
 }
 EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL);
 
-void cxl_cor_error_detected(struct pci_dev *pdev)
+static void __cxl_handle_cor_ras(struct cxl_dev_state *cxlds,
+				 void __iomem *ras_base)
 {
-	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
 	void __iomem *addr;
 	u32 status;
 
-	if (!cxlds->regs.ras)
+	if (!ras_base)
 		return;
 
-	addr = cxlds->regs.ras + CXL_RAS_CORRECTABLE_STATUS_OFFSET;
+	addr = ras_base + CXL_RAS_CORRECTABLE_STATUS_OFFSET;
 	status = readl(addr);
 	if (status & CXL_RAS_CORRECTABLE_STATUS_MASK) {
 		writel(status & CXL_RAS_CORRECTABLE_STATUS_MASK, addr);
 		trace_cxl_aer_correctable_error(cxlds->cxlmd, status);
 	}
 }
-EXPORT_SYMBOL_NS_GPL(cxl_cor_error_detected, CXL);
+
+static void cxl_handle_endpoint_cor_ras(struct cxl_dev_state *cxlds)
+{
+	return __cxl_handle_cor_ras(cxlds, cxlds->regs.ras);
+}
 
 /* CXL spec rev3.0 8.2.4.16.1 */
-static void header_log_copy(struct cxl_dev_state *cxlds, u32 *log)
+static void header_log_copy(void __iomem *ras_base, u32 *log)
 {
 	void __iomem *addr;
 	u32 *log_addr;
 	int i, log_u32_size = CXL_HEADERLOG_SIZE / sizeof(u32);
 
-	addr = cxlds->regs.ras + CXL_RAS_HEADER_LOG_OFFSET;
+	addr = ras_base + CXL_RAS_HEADER_LOG_OFFSET;
 	log_addr = log;
 
 	for (i = 0; i < log_u32_size; i++) {
@@ -685,17 +690,18 @@ static void header_log_copy(struct cxl_dev_state *cxlds, u32 *log)
  * Log the state of the RAS status registers and prepare them to log the
  * next error status. Return 1 if reset needed.
  */
-static bool cxl_report_and_clear(struct cxl_dev_state *cxlds)
+static bool __cxl_handle_ras(struct cxl_dev_state *cxlds,
+				  void __iomem *ras_base)
 {
 	u32 hl[CXL_HEADERLOG_SIZE_U32];
 	void __iomem *addr;
 	u32 status;
 	u32 fe;
 
-	if (!cxlds->regs.ras)
+	if (!ras_base)
 		return false;
 
-	addr = cxlds->regs.ras + CXL_RAS_UNCORRECTABLE_STATUS_OFFSET;
+	addr = ras_base + CXL_RAS_UNCORRECTABLE_STATUS_OFFSET;
 	status = readl(addr);
 	if (!(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK))
 		return false;
@@ -703,7 +709,7 @@ static bool cxl_report_and_clear(struct cxl_dev_state *cxlds)
 	/* If multiple errors, log header points to first error from ctrl reg */
 	if (hweight32(status) > 1) {
 		void __iomem *rcc_addr =
-			cxlds->regs.ras + CXL_RAS_CAP_CONTROL_OFFSET;
+			ras_base + CXL_RAS_CAP_CONTROL_OFFSET;
 
 		fe = BIT(FIELD_GET(CXL_RAS_CAP_CONTROL_FE_MASK,
 				   readl(rcc_addr)));
@@ -711,13 +717,201 @@ static bool cxl_report_and_clear(struct cxl_dev_state *cxlds)
 		fe = status;
 	}
 
-	header_log_copy(cxlds, hl);
+	header_log_copy(ras_base, hl);
 	trace_cxl_aer_uncorrectable_error(cxlds->cxlmd, status, fe, hl);
 	writel(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK, addr);
 
 	return true;
 }
 
+static bool cxl_handle_endpoint_ras(struct cxl_dev_state *cxlds)
+{
+	return __cxl_handle_ras(cxlds, cxlds->regs.ras);
+}
+
+#ifdef CONFIG_PCIEAER_CXL
+
+static void cxl_dport_map_rch_aer(struct cxl_dport *dport)
+{
+	struct cxl_rcrb_info *ri = &dport->rcrb;
+	void __iomem *dport_aer = NULL;
+	resource_size_t aer_phys;
+	struct device *host;
+
+	if (dport->rch && ri->aer_cap) {
+		host = dport->reg_map.host;
+		aer_phys = ri->aer_cap + ri->base;
+		dport_aer = devm_cxl_iomap_block(host, aer_phys,
+				sizeof(struct aer_capability_regs));
+	}
+
+	dport->regs.dport_aer = dport_aer;
+}
+
+static void cxl_dport_map_regs(struct cxl_dport *dport)
+{
+	struct cxl_register_map *map = &dport->reg_map;
+	struct device *dev = dport->dport_dev;
+
+	if (!map->component_map.ras.valid)
+		dev_dbg(dev, "RAS registers not found\n");
+	else if (cxl_map_component_regs(map, &dport->regs.component,
+					BIT(CXL_CM_CAP_CAP_ID_RAS)))
+		dev_dbg(dev, "Failed to map RAS capability.\n");
+
+	if (dport->rch)
+		cxl_dport_map_rch_aer(dport);
+}
+
+static void cxl_disable_rch_root_ints(struct cxl_dport *dport)
+{
+	void __iomem *aer_base = dport->regs.dport_aer;
+	struct pci_host_bridge *bridge;
+	u32 aer_cmd_mask, aer_cmd;
+
+	if (!aer_base)
+		return;
+
+	bridge = to_pci_host_bridge(dport->dport_dev);
+
+	/*
+	 * Disable RCH root port command interrupts.
+	 * CXL 3.0 12.2.1.1 - RCH Downstream Port-detected Errors
+	 *
+	 * This sequence may not be necessary. CXL spec states disabling
+	 * the root cmd register's interrupts is required. But, PCI spec
+	 * shows these are disabled by default on reset.
+	 */
+	if (bridge->native_cxl_error) {
+		aer_cmd_mask = (PCI_ERR_ROOT_CMD_COR_EN |
+				PCI_ERR_ROOT_CMD_NONFATAL_EN |
+				PCI_ERR_ROOT_CMD_FATAL_EN);
+		aer_cmd = readl(aer_base + PCI_ERR_ROOT_COMMAND);
+		aer_cmd &= ~aer_cmd_mask;
+		writel(aer_cmd, aer_base + PCI_ERR_ROOT_COMMAND);
+	}
+}
+
+void cxl_setup_parent_dport(struct device *host, struct cxl_dport *dport)
+{
+	struct device *dport_dev = dport->dport_dev;
+	struct pci_host_bridge *host_bridge;
+
+	host_bridge = to_pci_host_bridge(dport_dev);
+	if (host_bridge->native_cxl_error)
+		dport->rcrb.aer_cap = cxl_rcrb_to_aer(dport_dev, dport->rcrb.base);
+
+	dport->reg_map.host = host;
+	cxl_dport_map_regs(dport);
+
+	if (dport->rch)
+		cxl_disable_rch_root_ints(dport);
+}
+EXPORT_SYMBOL_NS_GPL(cxl_setup_parent_dport, CXL);
+
+static void cxl_handle_rdport_cor_ras(struct cxl_dev_state *cxlds,
+					  struct cxl_dport *dport)
+{
+	return __cxl_handle_cor_ras(cxlds, dport->regs.ras);
+}
+
+static bool cxl_handle_rdport_ras(struct cxl_dev_state *cxlds,
+				       struct cxl_dport *dport)
+{
+	return __cxl_handle_ras(cxlds, dport->regs.ras);
+}
+
+/*
+ * Copy the AER capability registers using 32 bit read accesses.
+ * This is necessary because RCRB AER capability is MMIO mapped. Clear the
+ * status after copying.
+ *
+ * @aer_base: base address of AER capability block in RCRB
+ * @aer_regs: destination for copying AER capability
+ */
+static bool cxl_rch_get_aer_info(void __iomem *aer_base,
+				 struct aer_capability_regs *aer_regs)
+{
+	int read_cnt = sizeof(struct aer_capability_regs) / sizeof(u32);
+	u32 *aer_regs_buf = (u32 *)aer_regs;
+	int n;
+
+	if (!aer_base)
+		return false;
+
+	/* Use readl() to guarantee 32-bit accesses */
+	for (n = 0; n < read_cnt; n++)
+		aer_regs_buf[n] = readl(aer_base + n * sizeof(u32));
+
+	writel(aer_regs->uncor_status, aer_base + PCI_ERR_UNCOR_STATUS);
+	writel(aer_regs->cor_status, aer_base + PCI_ERR_COR_STATUS);
+
+	return true;
+}
+
+/* Get AER severity. Return false if there is no error. */
+static bool cxl_rch_get_aer_severity(struct aer_capability_regs *aer_regs,
+				     int *severity)
+{
+	if (aer_regs->uncor_status & ~aer_regs->uncor_mask) {
+		if (aer_regs->uncor_status & PCI_ERR_ROOT_FATAL_RCV)
+			*severity = AER_FATAL;
+		else
+			*severity = AER_NONFATAL;
+		return true;
+	}
+
+	if (aer_regs->cor_status & ~aer_regs->cor_mask) {
+		*severity = AER_CORRECTABLE;
+		return true;
+	}
+
+	return false;
+}
+
+static void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds)
+{
+	struct pci_dev *pdev = to_pci_dev(cxlds->dev);
+	struct aer_capability_regs aer_regs;
+	struct cxl_dport *dport;
+	struct cxl_port *port;
+	int severity;
+
+	port = cxl_pci_find_port(pdev, &dport);
+	if (!port)
+		return;
+
+	put_device(&port->dev);
+
+	if (!cxl_rch_get_aer_info(dport->regs.dport_aer, &aer_regs))
+		return;
+
+	if (!cxl_rch_get_aer_severity(&aer_regs, &severity))
+		return;
+
+	pci_print_aer(pdev, severity, &aer_regs);
+
+	if (severity == AER_CORRECTABLE)
+		cxl_handle_rdport_cor_ras(cxlds, dport);
+	else
+		cxl_handle_rdport_ras(cxlds, dport);
+}
+
+#else
+static void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds) { }
+#endif
+
+void cxl_cor_error_detected(struct pci_dev *pdev)
+{
+	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
+
+	if (cxlds->rcd)
+		cxl_handle_rdport_errors(cxlds);
+
+	cxl_handle_endpoint_cor_ras(cxlds);
+}
+EXPORT_SYMBOL_NS_GPL(cxl_cor_error_detected, CXL);
+
 pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
 				    pci_channel_state_t state)
 {
@@ -726,13 +920,16 @@ pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
 	struct device *dev = &cxlmd->dev;
 	bool ue;
 
+	if (cxlds->rcd)
+		cxl_handle_rdport_errors(cxlds);
+
 	/*
 	 * A frozen channel indicates an impending reset which is fatal to
 	 * CXL.mem operation, and will likely crash the system. On the off
 	 * chance the situation is recoverable dump the status of the RAS
 	 * capability registers and bounce the active state of the memdev.
 	 */
-	ue = cxl_report_and_clear(cxlds);
+	ue = cxl_handle_endpoint_ras(cxlds);
 
 	switch (state) {
 	case pci_channel_io_normal:
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 5ba606c6e03f..e2f888224362 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -625,7 +625,6 @@ static int devm_cxl_link_parent_dport(struct device *host,
 static struct lock_class_key cxl_port_key;
 
 static struct cxl_port *cxl_port_alloc(struct device *uport_dev,
-				       resource_size_t component_reg_phys,
 				       struct cxl_dport *parent_dport)
 {
 	struct cxl_port *port;
@@ -676,7 +675,6 @@ static struct cxl_port *cxl_port_alloc(struct device *uport_dev,
 	} else
 		dev->parent = uport_dev;
 
-	port->component_reg_phys = component_reg_phys;
 	ida_init(&port->decoder_ida);
 	port->hdm_end = -1;
 	port->commit_end = -1;
@@ -697,19 +695,21 @@ err:
 	return ERR_PTR(rc);
 }
 
-static int cxl_setup_comp_regs(struct device *dev, struct cxl_register_map *map,
+static int cxl_setup_comp_regs(struct device *host, struct cxl_register_map *map,
 			       resource_size_t component_reg_phys)
 {
-	if (component_reg_phys == CXL_RESOURCE_NONE)
-		return 0;
-
 	*map = (struct cxl_register_map) {
-		.dev = dev,
-		.reg_type = CXL_REGLOC_RBI_COMPONENT,
+		.host = host,
+		.reg_type = CXL_REGLOC_RBI_EMPTY,
 		.resource = component_reg_phys,
-		.max_size = CXL_COMPONENT_REG_BLOCK_SIZE,
 	};
 
+	if (component_reg_phys == CXL_RESOURCE_NONE)
+		return 0;
+
+	map->reg_type = CXL_REGLOC_RBI_COMPONENT;
+	map->max_size = CXL_COMPONENT_REG_BLOCK_SIZE;
+
 	return cxl_setup_regs(map);
 }
 
@@ -718,17 +718,27 @@ static int cxl_port_setup_regs(struct cxl_port *port,
 {
 	if (dev_is_platform(port->uport_dev))
 		return 0;
-	return cxl_setup_comp_regs(&port->dev, &port->comp_map,
+	return cxl_setup_comp_regs(&port->dev, &port->reg_map,
 				   component_reg_phys);
 }
 
-static int cxl_dport_setup_regs(struct cxl_dport *dport,
+static int cxl_dport_setup_regs(struct device *host, struct cxl_dport *dport,
 				resource_size_t component_reg_phys)
 {
+	int rc;
+
 	if (dev_is_platform(dport->dport_dev))
 		return 0;
-	return cxl_setup_comp_regs(dport->dport_dev, &dport->comp_map,
-				   component_reg_phys);
+
+	/*
+	 * use @dport->dport_dev for the context for error messages during
+	 * register probing, and fixup @host after the fact, since @host may be
+	 * NULL.
+	 */
+	rc = cxl_setup_comp_regs(dport->dport_dev, &dport->reg_map,
+				 component_reg_phys);
+	dport->reg_map.host = host;
+	return rc;
 }
 
 static struct cxl_port *__devm_cxl_add_port(struct device *host,
@@ -740,21 +750,36 @@ static struct cxl_port *__devm_cxl_add_port(struct device *host,
 	struct device *dev;
 	int rc;
 
-	port = cxl_port_alloc(uport_dev, component_reg_phys, parent_dport);
+	port = cxl_port_alloc(uport_dev, parent_dport);
 	if (IS_ERR(port))
 		return port;
 
 	dev = &port->dev;
-	if (is_cxl_memdev(uport_dev))
+	if (is_cxl_memdev(uport_dev)) {
+		struct cxl_memdev *cxlmd = to_cxl_memdev(uport_dev);
+		struct cxl_dev_state *cxlds = cxlmd->cxlds;
+
 		rc = dev_set_name(dev, "endpoint%d", port->id);
-	else if (parent_dport)
+		if (rc)
+			goto err;
+
+		/*
+		 * The endpoint driver already enumerated the component and RAS
+		 * registers. Reuse that enumeration while prepping them to be
+		 * mapped by the cxl_port driver.
+		 */
+		port->reg_map = cxlds->reg_map;
+		port->reg_map.host = &port->dev;
+	} else if (parent_dport) {
 		rc = dev_set_name(dev, "port%d", port->id);
-	else
-		rc = dev_set_name(dev, "root%d", port->id);
-	if (rc)
-		goto err;
+		if (rc)
+			goto err;
 
-	rc = cxl_port_setup_regs(port, component_reg_phys);
+		rc = cxl_port_setup_regs(port, component_reg_phys);
+		if (rc)
+			goto err;
+	} else
+		rc = dev_set_name(dev, "root%d", port->id);
 	if (rc)
 		goto err;
 
@@ -989,7 +1014,16 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
 	if (!dport)
 		return ERR_PTR(-ENOMEM);
 
-	if (rcrb != CXL_RESOURCE_NONE) {
+	dport->dport_dev = dport_dev;
+	dport->port_id = port_id;
+	dport->port = port;
+
+	if (rcrb == CXL_RESOURCE_NONE) {
+		rc = cxl_dport_setup_regs(&port->dev, dport,
+					  component_reg_phys);
+		if (rc)
+			return ERR_PTR(rc);
+	} else {
 		dport->rcrb.base = rcrb;
 		component_reg_phys = __rcrb_to_component(dport_dev, &dport->rcrb,
 							 CXL_RCRB_DOWNSTREAM);
@@ -998,6 +1032,14 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
 			return ERR_PTR(-ENXIO);
 		}
 
+		/*
+		 * RCH @dport is not ready to map until associated with its
+		 * memdev
+		 */
+		rc = cxl_dport_setup_regs(NULL, dport, component_reg_phys);
+		if (rc)
+			return ERR_PTR(rc);
+
 		dport->rch = true;
 	}
 
@@ -1005,14 +1047,6 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
 		dev_dbg(dport_dev, "Component Registers found for dport: %pa\n",
 			&component_reg_phys);
 
-	dport->dport_dev = dport_dev;
-	dport->port_id = port_id;
-	dport->port = port;
-
-	rc = cxl_dport_setup_regs(dport, component_reg_phys);
-	if (rc)
-		return ERR_PTR(rc);
-
 	cond_cxl_root_lock(port);
 	rc = add_dport(port, dport);
 	cond_cxl_root_unlock(port);
@@ -1223,35 +1257,39 @@ static struct device *grandparent(struct device *dev)
 	return NULL;
 }
 
+static struct device *endpoint_host(struct cxl_port *endpoint)
+{
+	struct cxl_port *port = to_cxl_port(endpoint->dev.parent);
+
+	if (is_cxl_root(port))
+		return port->uport_dev;
+	return &port->dev;
+}
+
 static void delete_endpoint(void *data)
 {
 	struct cxl_memdev *cxlmd = data;
 	struct cxl_port *endpoint = cxlmd->endpoint;
-	struct cxl_port *parent_port;
-	struct device *parent;
+	struct device *host = endpoint_host(endpoint);
 
-	parent_port = cxl_mem_find_port(cxlmd, NULL);
-	if (!parent_port)
-		goto out;
-	parent = &parent_port->dev;
-
-	device_lock(parent);
-	if (parent->driver && !endpoint->dead) {
-		devm_release_action(parent, cxl_unlink_parent_dport, endpoint);
-		devm_release_action(parent, cxl_unlink_uport, endpoint);
-		devm_release_action(parent, unregister_port, endpoint);
+	device_lock(host);
+	if (host->driver && !endpoint->dead) {
+		devm_release_action(host, cxl_unlink_parent_dport, endpoint);
+		devm_release_action(host, cxl_unlink_uport, endpoint);
+		devm_release_action(host, unregister_port, endpoint);
 	}
 	cxlmd->endpoint = NULL;
-	device_unlock(parent);
-	put_device(parent);
-out:
+	device_unlock(host);
 	put_device(&endpoint->dev);
+	put_device(host);
 }
 
 int cxl_endpoint_autoremove(struct cxl_memdev *cxlmd, struct cxl_port *endpoint)
 {
+	struct device *host = endpoint_host(endpoint);
 	struct device *dev = &cxlmd->dev;
 
+	get_device(host);
 	get_device(&endpoint->dev);
 	cxlmd->endpoint = endpoint;
 	cxlmd->depth = endpoint->depth;
@@ -2068,3 +2106,4 @@ static void cxl_core_exit(void)
 subsys_initcall(cxl_core_init);
 module_exit(cxl_core_exit);
 MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(CXL);
diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
index 6281127b3e9d..372786f80955 100644
--- a/drivers/cxl/core/regs.c
+++ b/drivers/cxl/core/regs.c
@@ -204,7 +204,7 @@ int cxl_map_component_regs(const struct cxl_register_map *map,
 			   struct cxl_component_regs *regs,
 			   unsigned long map_mask)
 {
-	struct device *dev = map->dev;
+	struct device *host = map->host;
 	struct mapinfo {
 		const struct cxl_reg_map *rmap;
 		void __iomem **addr;
@@ -216,16 +216,16 @@ int cxl_map_component_regs(const struct cxl_register_map *map,
 
 	for (i = 0; i < ARRAY_SIZE(mapinfo); i++) {
 		struct mapinfo *mi = &mapinfo[i];
-		resource_size_t phys_addr;
+		resource_size_t addr;
 		resource_size_t length;
 
 		if (!mi->rmap->valid)
 			continue;
 		if (!test_bit(mi->rmap->id, &map_mask))
 			continue;
-		phys_addr = map->resource + mi->rmap->offset;
+		addr = map->resource + mi->rmap->offset;
 		length = mi->rmap->size;
-		*(mi->addr) = devm_cxl_iomap_block(dev, phys_addr, length);
+		*(mi->addr) = devm_cxl_iomap_block(host, addr, length);
 		if (!*(mi->addr))
 			return -ENOMEM;
 	}
@@ -237,7 +237,7 @@ EXPORT_SYMBOL_NS_GPL(cxl_map_component_regs, CXL);
 int cxl_map_device_regs(const struct cxl_register_map *map,
 			struct cxl_device_regs *regs)
 {
-	struct device *dev = map->dev;
+	struct device *host = map->host;
 	resource_size_t phys_addr = map->resource;
 	struct mapinfo {
 		const struct cxl_reg_map *rmap;
@@ -259,7 +259,7 @@ int cxl_map_device_regs(const struct cxl_register_map *map,
 
 		addr = phys_addr + mi->rmap->offset;
 		length = mi->rmap->size;
-		*(mi->addr) = devm_cxl_iomap_block(dev, addr, length);
+		*(mi->addr) = devm_cxl_iomap_block(host, addr, length);
 		if (!*(mi->addr))
 			return -ENOMEM;
 	}
@@ -309,7 +309,7 @@ int cxl_find_regblock_instance(struct pci_dev *pdev, enum cxl_regloc_type type,
 	int regloc, i;
 
 	*map = (struct cxl_register_map) {
-		.dev = &pdev->dev,
+		.host = &pdev->dev,
 		.resource = CXL_RESOURCE_NONE,
 	};
 
@@ -386,10 +386,9 @@ int cxl_count_regblock(struct pci_dev *pdev, enum cxl_regloc_type type)
 }
 EXPORT_SYMBOL_NS_GPL(cxl_count_regblock, CXL);
 
-int cxl_map_pmu_regs(struct pci_dev *pdev, struct cxl_pmu_regs *regs,
-		     struct cxl_register_map *map)
+int cxl_map_pmu_regs(struct cxl_register_map *map, struct cxl_pmu_regs *regs)
 {
-	struct device *dev = &pdev->dev;
+	struct device *dev = map->host;
 	resource_size_t phys_addr;
 
 	phys_addr = map->resource;
@@ -403,15 +402,15 @@ EXPORT_SYMBOL_NS_GPL(cxl_map_pmu_regs, CXL);
 
 static int cxl_map_regblock(struct cxl_register_map *map)
 {
-	struct device *dev = map->dev;
+	struct device *host = map->host;
 
 	map->base = ioremap(map->resource, map->max_size);
 	if (!map->base) {
-		dev_err(dev, "failed to map registers\n");
+		dev_err(host, "failed to map registers\n");
 		return -ENOMEM;
 	}
 
-	dev_dbg(dev, "Mapped CXL Memory Device resource %pa\n", &map->resource);
+	dev_dbg(host, "Mapped CXL Memory Device resource %pa\n", &map->resource);
 	return 0;
 }
 
@@ -425,28 +424,28 @@ static int cxl_probe_regs(struct cxl_register_map *map)
 {
 	struct cxl_component_reg_map *comp_map;
 	struct cxl_device_reg_map *dev_map;
-	struct device *dev = map->dev;
+	struct device *host = map->host;
 	void __iomem *base = map->base;
 
 	switch (map->reg_type) {
 	case CXL_REGLOC_RBI_COMPONENT:
 		comp_map = &map->component_map;
-		cxl_probe_component_regs(dev, base, comp_map);
-		dev_dbg(dev, "Set up component registers\n");
+		cxl_probe_component_regs(host, base, comp_map);
+		dev_dbg(host, "Set up component registers\n");
 		break;
 	case CXL_REGLOC_RBI_MEMDEV:
 		dev_map = &map->device_map;
-		cxl_probe_device_regs(dev, base, dev_map);
+		cxl_probe_device_regs(host, base, dev_map);
 		if (!dev_map->status.valid || !dev_map->mbox.valid ||
 		    !dev_map->memdev.valid) {
-			dev_err(dev, "registers not found: %s%s%s\n",
+			dev_err(host, "registers not found: %s%s%s\n",
 				!dev_map->status.valid ? "status " : "",
 				!dev_map->mbox.valid ? "mbox " : "",
 				!dev_map->memdev.valid ? "memdev " : "");
 			return -ENXIO;
 		}
 
-		dev_dbg(dev, "Probing device registers...\n");
+		dev_dbg(host, "Probing device registers...\n");
 		break;
 	default:
 		break;
@@ -470,6 +469,42 @@ int cxl_setup_regs(struct cxl_register_map *map)
 }
 EXPORT_SYMBOL_NS_GPL(cxl_setup_regs, CXL);
 
+u16 cxl_rcrb_to_aer(struct device *dev, resource_size_t rcrb)
+{
+	void __iomem *addr;
+	u16 offset = 0;
+	u32 cap_hdr;
+
+	if (WARN_ON_ONCE(rcrb == CXL_RESOURCE_NONE))
+		return 0;
+
+	if (!request_mem_region(rcrb, SZ_4K, dev_name(dev)))
+		return 0;
+
+	addr = ioremap(rcrb, SZ_4K);
+	if (!addr)
+		goto out;
+
+	cap_hdr = readl(addr + offset);
+	while (PCI_EXT_CAP_ID(cap_hdr) != PCI_EXT_CAP_ID_ERR) {
+		offset = PCI_EXT_CAP_NEXT(cap_hdr);
+
+		/* Offset 0 terminates capability list. */
+		if (!offset)
+			break;
+		cap_hdr = readl(addr + offset);
+	}
+
+	if (offset)
+		dev_dbg(dev, "found AER extended capability (0x%x)\n", offset);
+
+	iounmap(addr);
+out:
+	release_mem_region(rcrb, SZ_4K);
+
+	return offset;
+}
+
 resource_size_t __rcrb_to_component(struct device *dev, struct cxl_rcrb_info *ri,
 				    enum cxl_rcrb which)
 {
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 76d92561af29..378fc96ff7ff 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -221,6 +221,14 @@ struct cxl_regs {
 	struct_group_tagged(cxl_pmu_regs, pmu_regs,
 		void __iomem *pmu;
 	);
+
+	/*
+	 * RCH downstream port specific RAS register
+	 * @aer: CXL 3.0 8.2.1.1 RCH Downstream Port RCRB
+	 */
+	struct_group_tagged(cxl_rch_regs, rch_regs,
+		void __iomem *dport_aer;
+	);
 };
 
 struct cxl_reg_map {
@@ -247,7 +255,7 @@ struct cxl_pmu_reg_map {
 
 /**
  * struct cxl_register_map - DVSEC harvested register block mapping parameters
- * @dev: device for devm operations and logging
+ * @host: device for devm operations and logging
  * @base: virtual base of the register-block-BAR + @block_offset
  * @resource: physical resource base of the register block
  * @max_size: maximum mapping size to perform register search
@@ -257,7 +265,7 @@ struct cxl_pmu_reg_map {
  * @pmu_map: cxl_reg_maps for CXL Performance Monitoring Units
  */
 struct cxl_register_map {
-	struct device *dev;
+	struct device *host;
 	void __iomem *base;
 	resource_size_t resource;
 	resource_size_t max_size;
@@ -278,8 +286,7 @@ int cxl_map_component_regs(const struct cxl_register_map *map,
 			   unsigned long map_mask);
 int cxl_map_device_regs(const struct cxl_register_map *map,
 			struct cxl_device_regs *regs);
-int cxl_map_pmu_regs(struct pci_dev *pdev, struct cxl_pmu_regs *regs,
-		     struct cxl_register_map *map);
+int cxl_map_pmu_regs(struct cxl_register_map *map, struct cxl_pmu_regs *regs);
 
 enum cxl_regloc_type;
 int cxl_count_regblock(struct pci_dev *pdev, enum cxl_regloc_type type);
@@ -572,11 +579,10 @@ struct cxl_dax_region {
  * @regions: cxl_region_ref instances, regions mapped by this port
  * @parent_dport: dport that points to this port in the parent
  * @decoder_ida: allocator for decoder ids
- * @comp_map: component register capability mappings
+ * @reg_map: component and ras register mapping parameters
  * @nr_dports: number of entries in @dports
  * @hdm_end: track last allocated HDM decoder instance for allocation ordering
  * @commit_end: cursor to track highest committed decoder for commit ordering
- * @component_reg_phys: component register capability base address (optional)
  * @dead: last ep has been removed, force port re-creation
  * @depth: How deep this port is relative to the root. depth 0 is the root.
  * @cdat: Cached CDAT data
@@ -592,11 +598,10 @@ struct cxl_port {
 	struct xarray regions;
 	struct cxl_dport *parent_dport;
 	struct ida decoder_ida;
-	struct cxl_register_map comp_map;
+	struct cxl_register_map reg_map;
 	int nr_dports;
 	int hdm_end;
 	int commit_end;
-	resource_size_t component_reg_phys;
 	bool dead;
 	unsigned int depth;
 	struct cxl_cdat {
@@ -620,19 +625,21 @@ struct cxl_rcrb_info {
 /**
  * struct cxl_dport - CXL downstream port
  * @dport_dev: PCI bridge or firmware device representing the downstream link
- * @comp_map: component register capability mappings
+ * @reg_map: component and ras register mapping parameters
  * @port_id: unique hardware identifier for dport in decoder target list
  * @rcrb: Data about the Root Complex Register Block layout
  * @rch: Indicate whether this dport was enumerated in RCH or VH mode
  * @port: reference to cxl_port that contains this downstream port
+ * @regs: Dport parsed register blocks
  */
 struct cxl_dport {
 	struct device *dport_dev;
-	struct cxl_register_map comp_map;
+	struct cxl_register_map reg_map;
 	int port_id;
 	struct cxl_rcrb_info rcrb;
 	bool rch;
 	struct cxl_port *port;
+	struct cxl_regs regs;
 };
 
 /**
@@ -706,6 +713,13 @@ struct cxl_dport *devm_cxl_add_rch_dport(struct cxl_port *port,
 					 struct device *dport_dev, int port_id,
 					 resource_size_t rcrb);
 
+#ifdef CONFIG_PCIEAER_CXL
+void cxl_setup_parent_dport(struct device *host, struct cxl_dport *dport);
+#else
+static inline void cxl_setup_parent_dport(struct device *host,
+					  struct cxl_dport *dport) { }
+#endif
+
 struct cxl_decoder *to_cxl_decoder(struct device *dev);
 struct cxl_root_decoder *to_cxl_root_decoder(struct device *dev);
 struct cxl_switch_decoder *to_cxl_switch_decoder(struct device *dev);
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 6933bc20e76b..a2fcbca253f3 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -400,6 +400,7 @@ enum cxl_devtype {
  *
  * @dev: The device associated with this CXL state
  * @cxlmd: The device representing the CXL.mem capabilities of @dev
+ * @reg_map: component and ras register mapping parameters
  * @regs: Parsed register blocks
  * @cxl_dvsec: Offset to the PCIe device DVSEC
  * @rcd: operating in RCD mode (CXL 3.0 9.11.8 CXL Devices Attached to an RCH)
@@ -407,13 +408,13 @@ enum cxl_devtype {
  * @dpa_res: Overall DPA resource tree for the device
  * @pmem_res: Active Persistent memory capacity configuration
  * @ram_res: Active Volatile memory capacity configuration
- * @component_reg_phys: register base of component registers
  * @serial: PCIe Device Serial Number
  * @type: Generic Memory Class device or Vendor Specific Memory device
  */
 struct cxl_dev_state {
 	struct device *dev;
 	struct cxl_memdev *cxlmd;
+	struct cxl_register_map reg_map;
 	struct cxl_regs regs;
 	int cxl_dvsec;
 	bool rcd;
@@ -421,7 +422,6 @@ struct cxl_dev_state {
 	struct resource dpa_res;
 	struct resource pmem_res;
 	struct resource ram_res;
-	resource_size_t component_reg_phys;
 	u64 serial;
 	enum cxl_devtype type;
 };
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 317c7548e4e9..e087febf9af0 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -49,7 +49,6 @@ static int devm_cxl_add_endpoint(struct device *host, 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;
 
@@ -65,8 +64,8 @@ static int devm_cxl_add_endpoint(struct device *host, struct cxl_memdev *cxlmd,
 		ep->next = down;
 	}
 
-	endpoint = devm_cxl_add_port(host, &cxlmd->dev,
-				     cxlds->component_reg_phys,
+	/* Note: endpoint port component registers are derived from @cxlds */
+	endpoint = devm_cxl_add_port(host, &cxlmd->dev, CXL_RESOURCE_NONE,
 				     parent_dport);
 	if (IS_ERR(endpoint))
 		return PTR_ERR(endpoint);
@@ -158,6 +157,8 @@ static int cxl_mem_probe(struct device *dev)
 	else
 		endpoint_parent = &parent_port->dev;
 
+	cxl_setup_parent_dport(dev, dport);
+
 	device_lock(endpoint_parent);
 	if (!endpoint_parent->driver) {
 		dev_err(dev, "CXL port topology %s not enabled\n",
diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 06fafe59c054..4067afca6389 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -474,7 +474,7 @@ static int cxl_rcrb_get_comp_regs(struct pci_dev *pdev,
 	resource_size_t component_reg_phys;
 
 	*map = (struct cxl_register_map) {
-		.dev = &pdev->dev,
+		.host = &pdev->dev,
 		.resource = CXL_RESOURCE_NONE,
 	};
 
@@ -824,16 +824,14 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	 * If the component registers can't be found, the cxl_pci driver may
 	 * still be useful for management functions so don't return an error.
 	 */
-	cxlds->component_reg_phys = CXL_RESOURCE_NONE;
-	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_COMPONENT, &map);
+	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_COMPONENT,
+				&cxlds->reg_map);
 	if (rc)
 		dev_warn(&pdev->dev, "No component registers (%d)\n", rc);
-	else if (!map.component_map.ras.valid)
+	else if (!cxlds->reg_map.component_map.ras.valid)
 		dev_dbg(&pdev->dev, "RAS registers not found\n");
 
-	cxlds->component_reg_phys = map.resource;
-
-	rc = cxl_map_component_regs(&map, &cxlds->regs.component,
+	rc = cxl_map_component_regs(&cxlds->reg_map, &cxlds->regs.component,
 				    BIT(CXL_CM_CAP_CAP_ID_RAS));
 	if (rc)
 		dev_dbg(&pdev->dev, "Failed to map RAS capability.\n");
@@ -894,7 +892,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 			break;
 		}
 
-		rc = cxl_map_pmu_regs(pdev, &pmu_regs, &map);
+		rc = cxl_map_pmu_regs(&map, &pmu_regs);
 		if (rc) {
 			dev_dbg(&pdev->dev, "Could not map PMU regs\n");
 			break;