Thread (88 messages) 88 messages, 6 authors, 2025-10-07

Re: [PATCH v18 04/20] cxl: allow Type2 drivers to map cxl component regs

From: Jonathan Cameron <jonathan.cameron@huawei.com>
Date: 2025-09-18 11:03:52
Also in: netdev

On Thu, 18 Sep 2025 10:17:30 +0100
alejandro.lucero-palau@amd.com wrote:
From: Alejandro Lucero <redacted>

Export cxl core functions for a Type2 driver being able to discover and
map the device component registers.

Use it in sfc driver cxl initialization.

Signed-off-by: Alejandro Lucero <redacted>
Reviewed-by: Dan Williams <redacted>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
quoted hunk ↗ jump to hunk
diff --git a/drivers/net/ethernet/sfc/efx_cxl.c b/drivers/net/ethernet/sfc/efx_cxl.c
index 56d148318636..cdfbe546d8d8 100644
--- a/drivers/net/ethernet/sfc/efx_cxl.c
+++ b/drivers/net/ethernet/sfc/efx_cxl.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2025, Advanced Micro Devices, Inc.
  */
 
+#include <cxl/cxl.h>
 #include <cxl/pci.h>
 #include <linux/pci.h>
 
@@ -19,6 +20,7 @@ int efx_cxl_init(struct efx_probe_data *probe_data)
 	struct pci_dev *pci_dev = efx->pci_dev;
 	struct efx_cxl *cxl;
 	u16 dvsec;
+	int rc;
 
 	probe_data->cxl_pio_initialised = false;
 
@@ -45,6 +47,37 @@ int efx_cxl_init(struct efx_probe_data *probe_data)
 	if (!cxl)
 		return -ENOMEM;
 
+	rc = cxl_pci_setup_regs(pci_dev, CXL_REGLOC_RBI_COMPONENT,
+				&cxl->cxlds.reg_map);
+	if (rc) {
+		dev_err(&pci_dev->dev, "No component registers (err=%d)\n", rc);
+		return rc;
+	}
+
+	if (!cxl->cxlds.reg_map.component_map.hdm_decoder.valid) {
+		dev_err(&pci_dev->dev, "Expected HDM component register not found\n");
+		return -ENODEV;
+	}
+
+	if (!cxl->cxlds.reg_map.component_map.ras.valid)
+		return dev_err_probe(&pci_dev->dev, -ENODEV,
+				     "Expected RAS component register not found\n");
Why the mix of dev_err() and dev_err_probe()?
I'd prefer dev_err_probe() for all these, but we definitely don't
want a mix.
quoted hunk ↗ jump to hunk
+
+	rc = cxl_map_component_regs(&cxl->cxlds.reg_map,
+				    &cxl->cxlds.regs.component,
+				    BIT(CXL_CM_CAP_CAP_ID_RAS));
+	if (rc) {
+		dev_err(&pci_dev->dev, "Failed to map RAS capability.\n");
+		return rc;
+	}
+
+	/*
+	 * Set media ready explicitly as there are neither mailbox for checking
+	 * this state nor the CXL register involved, both not mandatory for
+	 * type2.
+	 */
+	cxl->cxlds.media_ready = true;
+
 	probe_data->cxl = cxl;
 
 	return 0;
diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h
index 13d448686189..3b9c8cb187a3 100644
--- a/include/cxl/cxl.h
+++ b/include/cxl/cxl.h
+/**
+ * cxl_map_component_regs - map cxl component registers
+ *
Why 2 blank lines?
+ *
+ * @map: cxl register map to update with the mappings
+ * @regs: cxl component registers to work with
+ * @map_mask: cxl component regs to map
+ *
+ * Returns integer: success (0) or error (-ENOMEM)
+ *
+ * Made public for Type2 driver support.
+ */
+int cxl_map_component_regs(const struct cxl_register_map *map,
+			   struct cxl_component_regs *regs,
+			   unsigned long map_mask);
 #endif /* __CXL_CXL_H__ */
		       struct cxl_register_map *map);
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