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Message-ID: <20251104170305.4163840-7-terry.bowman@amd.com>
Date: Tue, 4 Nov 2025 11:02:46 -0600
From: Terry Bowman <terry.bowman@....com>
To: <dave@...olabs.net>, <jonathan.cameron@...wei.com>,
	<dave.jiang@...el.com>, <alison.schofield@...el.com>,
	<dan.j.williams@...el.com>, <bhelgaas@...gle.com>, <shiju.jose@...wei.com>,
	<ming.li@...omail.com>, <Smita.KoralahalliChannabasappa@....com>,
	<rrichter@....com>, <dan.carpenter@...aro.org>,
	<PradeepVineshReddy.Kodamati@....com>, <lukas@...ner.de>,
	<Benjamin.Cheatham@....com>, <sathyanarayanan.kuppuswamy@...ux.intel.com>,
	<linux-cxl@...r.kernel.org>, <alucerop@....com>, <ira.weiny@...el.com>
CC: <linux-kernel@...r.kernel.org>, <linux-pci@...r.kernel.org>,
	<terry.bowman@....com>
Subject: [RESEND v13 06/25] cxl: Move CXL driver's RCH error handling into core/ras_rch.c

Restricted CXL Host (RCH) protocol error handling uses a procedure distinct
from the CXL Virtual Hierarchy (VH) handling. This is because of the
differences in the RCH and VH topologies. Improve the maintainability and
add ability to enable/disable RCH handling.

Move and combine the RCH handling code into a single block conditionally
compiled with the CONFIG_CXL_RCH_RAS kernel config.

Signed-off-by: Terry Bowman <terry.bowman@....com>

---

Changes in v12->v13:
- None

Changes v11->v12:
- Moved CXL_RCH_RAS Kconfig definition here from following commit.

Changes v10->v11:
- New patch
---
 drivers/cxl/Kconfig        |   7 +++
 drivers/cxl/core/Makefile  |   1 +
 drivers/cxl/core/core.h    |   5 +-
 drivers/cxl/core/pci.c     | 115 -----------------------------------
 drivers/cxl/core/ras_rch.c | 120 +++++++++++++++++++++++++++++++++++++
 tools/testing/cxl/Kbuild   |   1 +
 6 files changed, 132 insertions(+), 117 deletions(-)
 create mode 100644 drivers/cxl/core/ras_rch.c

diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
index 217888992c88..ffe6ad981434 100644
--- a/drivers/cxl/Kconfig
+++ b/drivers/cxl/Kconfig
@@ -237,4 +237,11 @@ config CXL_RAS
 	def_bool y
 	depends on ACPI_APEI_GHES && PCIEAER && CXL_PCI
 
+config CXL_RCH_RAS
+	bool "CXL: Restricted CXL Host (RCH) protocol error handling"
+	def_bool n
+	depends on CXL_RAS
+	help
+	  RAS support for Restricted CXL Host (RCH) defined in CXL1.1.
+
 endif
diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
index b2930cc54f8b..fa1d4aed28b9 100644
--- a/drivers/cxl/core/Makefile
+++ b/drivers/cxl/core/Makefile
@@ -20,3 +20,4 @@ cxl_core-$(CONFIG_CXL_MCE) += mce.o
 cxl_core-$(CONFIG_CXL_FEATURES) += features.o
 cxl_core-$(CONFIG_CXL_EDAC_MEM_FEATURES) += edac.o
 cxl_core-$(CONFIG_CXL_RAS) += ras.o
+cxl_core-$(CONFIG_CXL_RCH_RAS) += ras_rch.o
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index bc818de87ccc..c30ab7c25a92 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -4,6 +4,7 @@
 #ifndef __CXL_CORE_H__
 #define __CXL_CORE_H__
 
+#include <linux/pci.h>
 #include <cxl/mailbox.h>
 #include <linux/rwsem.h>
 
@@ -167,7 +168,7 @@ static inline void cxl_handle_cor_ras(struct cxl_dev_state *cxlds, void __iomem
 #endif /* CONFIG_CXL_RAS */
 
 /* Restricted CXL Host specific RAS functions */
-#ifdef CONFIG_CXL_RAS
+#ifdef CONFIG_CXL_RCH_RAS
 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);
@@ -175,7 +176,7 @@ void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds);
 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) { }
-#endif /* CONFIG_CXL_RAS */
+#endif /* CONFIG_CXL_RCH_RAS */
 
 int cxl_gpf_port_setup(struct cxl_dport *dport);
 
diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index cd73cea93282..a66f7a84b5c8 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -711,121 +711,6 @@ void read_cdat_data(struct cxl_port *port)
 }
 EXPORT_SYMBOL_NS_GPL(read_cdat_data, "CXL");
 
-#ifdef CONFIG_CXL_RAS
-void cxl_dport_map_rch_aer(struct cxl_dport *dport)
-{
-	resource_size_t aer_phys;
-	struct device *host;
-	u16 aer_cap;
-
-	aer_cap = cxl_rcrb_to_aer(dport->dport_dev, dport->rcrb.base);
-	if (aer_cap) {
-		host = dport->reg_map.host;
-		aer_phys = aer_cap + dport->rcrb.base;
-		dport->regs.dport_aer = devm_cxl_iomap_block(host, aer_phys,
-						sizeof(struct aer_capability_regs));
-	}
-}
-
-void cxl_disable_rch_root_ints(struct cxl_dport *dport)
-{
-	void __iomem *aer_base = dport->regs.dport_aer;
-	u32 aer_cmd_mask, aer_cmd;
-
-	if (!aer_base)
-		return;
-
-	/*
-	 * 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.
-	 */
-	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);
-}
-
-/*
- * 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;
-}
-
-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;
-	int severity;
-
-	struct cxl_port *port __free(put_cxl_port) =
-		cxl_pci_find_port(pdev, &dport);
-	if (!port)
-		return;
-
-	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_cor_ras(cxlds, dport->regs.ras);
-	else
-		cxl_handle_ras(cxlds, dport->regs.ras);
-}
-#endif
-
 static int cxl_flit_size(struct pci_dev *pdev)
 {
 	if (cxl_pci_flit_256(pdev))
diff --git a/drivers/cxl/core/ras_rch.c b/drivers/cxl/core/ras_rch.c
new file mode 100644
index 000000000000..f6de5492a8b7
--- /dev/null
+++ b/drivers/cxl/core/ras_rch.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2025 AMD Corporation. All rights reserved. */
+
+#include <linux/pci.h>
+#include <linux/aer.h>
+#include <cxl/event.h>
+#include <cxlmem.h>
+#include "trace.h"
+
+void cxl_dport_map_rch_aer(struct cxl_dport *dport)
+{
+	resource_size_t aer_phys;
+	struct device *host;
+	u16 aer_cap;
+
+	aer_cap = cxl_rcrb_to_aer(dport->dport_dev, dport->rcrb.base);
+	if (aer_cap) {
+		host = dport->reg_map.host;
+		aer_phys = aer_cap + dport->rcrb.base;
+		dport->regs.dport_aer = devm_cxl_iomap_block(host, aer_phys,
+							     sizeof(struct aer_capability_regs));
+	}
+}
+
+void cxl_disable_rch_root_ints(struct cxl_dport *dport)
+{
+	void __iomem *aer_base = dport->regs.dport_aer;
+	u32 aer_cmd_mask, aer_cmd;
+
+	if (!aer_base)
+		return;
+
+	/*
+	 * 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.
+	 */
+	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);
+}
+
+/*
+ * 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;
+}
+
+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;
+	int severity;
+
+	struct cxl_port *port __free(put_cxl_port) =
+		cxl_pci_find_port(pdev, &dport);
+	if (!port)
+		return;
+
+	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_cor_ras(cxlds, dport->regs.ras);
+	else
+		cxl_handle_ras(cxlds, dport->regs.ras);
+}
diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
index 927fbb6c061f..6905f8e710ab 100644
--- a/tools/testing/cxl/Kbuild
+++ b/tools/testing/cxl/Kbuild
@@ -64,6 +64,7 @@ cxl_core-$(CONFIG_CXL_MCE) += $(CXL_CORE_SRC)/mce.o
 cxl_core-$(CONFIG_CXL_FEATURES) += $(CXL_CORE_SRC)/features.o
 cxl_core-$(CONFIG_CXL_EDAC_MEM_FEATURES) += $(CXL_CORE_SRC)/edac.o
 cxl_core-$(CONFIG_CXL_RAS) += $(CXL_CORE_SRC)/ras.o
+cxl_core-$(CONFIG_CXL_RCH_RAS) += $(CXL_CORE_SRC)/ras_rch.o
 cxl_core-y += config_check.o
 cxl_core-y += cxl_core_test.o
 cxl_core-y += cxl_core_exports.o
-- 
2.34.1


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