[PATCH v11 05/23] cxl: Move CXL driver RCH error handling into CONFIG_CXL_RCH_RAS conditional block

Terry Bowman
2025-08-27T01:36:46Z

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@amd.com>

---
v10->v11:
- New patch
---
drivers/cxl/core/ras.c | 175 +++++++++++++++++++++--------------------
1 file changed, 90 insertions(+), 85 deletions(-)

diff --git a/drivers/cxl/core/ras.c b/drivers/cxl/core/ras.c
index 0875ce8116ff..f42f9a255ef8 100644
--- a/drivers/cxl/core/ras.c
+++ b/drivers/cxl/core/ras.c
@@ -126,6 +126,7 @@ void cxl_ras_exit(void)
cancel_work_sync(&cxl_cper_prot_err_work);
}

+#ifdef CONFIG_CXL_RCH_RAS
static void cxl_dport_map_rch_aer(struct cxl_dport *dport)
{
resource_size_t aer_phys;
@@ -141,18 +142,6 @@ static void cxl_dport_map_rch_aer(struct cxl_dport *dport)
}
}

-static void cxl_dport_map_ras(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");
-}
-
static void cxl_disable_rch_root_ints(struct cxl_dport *dport)
{
void __iomem *aer_base = dport->regs.dport_aer;
@@ -177,6 +166,95 @@ static void cxl_disable_rch_root_ints(struct cxl_dport *dport)
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;
+}
+
+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;
+ 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);
+}
+#else
+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
+
+static void cxl_dport_map_ras(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");
+}

/**
* cxl_dport_init_ras_reporting - Setup CXL RAS report on this dport
@@ -270,79 +348,6 @@ static bool cxl_handle_ras(struct cxl_dev_state *cxlds, void __iomem *ras_base)
return true;
}

-/*
- * 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;
- 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);
-}
-
void cxl_cor_error_detected(struct pci_dev *pdev)
{
struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
--
2.51.0.rc2.21.ge5ab6b3e5a