cxl/pci: Refactor component register discovery for reuse

The endpoint implements component register setup code. Refactor it for
reuse with RCRB, downstream port, and upstream port setup.

Move PCI specifics from cxl_setup_regs() into cxl_pci_setup_regs().

Move cxl_setup_regs() into cxl/core/regs.c and export it. This also
includes supporting static functions cxl_map_registerblock(),
cxl_unmap_register_block() and cxl_probe_regs().
Co-developed-by: Robert Richter <rrichter@amd.com>
Signed-off-by: Robert Richter <rrichter@amd.com>
Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20230622205523.85375-8-terry.bowman@amd.comSigned-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/cxl/core/regs.c

@@ -338,6 +338,83 @@ int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
 }
 EXPORT_SYMBOL_NS_GPL(cxl_find_regblock, CXL);
 
+static int cxl_map_regblock(struct cxl_register_map *map)
+{
+	struct device *dev = map->dev;
+
+	map->base = ioremap(map->resource, map->max_size);
+	if (!map->base) {
+		dev_err(dev, "failed to map registers\n");
+		return -ENOMEM;
+	}
+
+	dev_dbg(dev, "Mapped CXL Memory Device resource %pa\n", &map->resource);
+	return 0;
+}
+
+static void cxl_unmap_regblock(struct cxl_register_map *map)
+{
+	iounmap(map->base);
+	map->base = NULL;
+}
+
+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;
+	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);
+		if (!comp_map->hdm_decoder.valid) {
+			dev_err(dev, "HDM decoder registers not found\n");
+			return -ENXIO;
+		}
+
+		if (!comp_map->ras.valid)
+			dev_dbg(dev, "RAS registers not found\n");
+
+		dev_dbg(dev, "Set up component registers\n");
+		break;
+	case CXL_REGLOC_RBI_MEMDEV:
+		dev_map = &map->device_map;
+		cxl_probe_device_regs(dev, 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_map->status.valid ? "status " : "",
+				!dev_map->mbox.valid ? "mbox " : "",
+				!dev_map->memdev.valid ? "memdev " : "");
+			return -ENXIO;
+		}
+
+		dev_dbg(dev, "Probing device registers...\n");
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+int cxl_setup_regs(struct cxl_register_map *map)
+{
+	int rc;
+
+	rc = cxl_map_regblock(map);
+	if (rc)
+		return rc;
+
+	rc = cxl_probe_regs(map);
+	cxl_unmap_regblock(map);
+
+	return rc;
+}
+EXPORT_SYMBOL_NS_GPL(cxl_setup_regs, CXL);
+
 resource_size_t __rcrb_to_component(struct device *dev, struct cxl_rcrb_info *ri,
 				    enum cxl_rcrb which)
 {

drivers/cxl/cxl.h

@@ -264,6 +264,7 @@ int cxl_map_device_regs(struct cxl_register_map *map,
 enum cxl_regloc_type;
 int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
 		      struct cxl_register_map *map);
+int cxl_setup_regs(struct cxl_register_map *map);
 struct cxl_dport;
 resource_size_t cxl_rcd_component_reg_phys(struct device *dev,
 					   struct cxl_dport *dport);

drivers/cxl/pci.c

@@ -274,69 +274,7 @@ static int cxl_pci_setup_mailbox(struct cxl_dev_state *cxlds)
 	return 0;
 }
 
-static int cxl_map_regblock(struct cxl_register_map *map)
-{
-	struct device *dev = map->dev;
-
-	map->base = ioremap(map->resource, map->max_size);
-	if (!map->base) {
-		dev_err(dev, "failed to map registers\n");
-		return -ENOMEM;
-	}
-
-	dev_dbg(dev, "Mapped CXL Memory Device resource %pa\n", &map->resource);
-	return 0;
-}
-
-static void cxl_unmap_regblock(struct cxl_register_map *map)
-{
-	iounmap(map->base);
-	map->base = NULL;
-}
-
-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;
-	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);
-		if (!comp_map->hdm_decoder.valid) {
-			dev_err(dev, "HDM decoder registers not found\n");
-			return -ENXIO;
-		}
-
-		if (!comp_map->ras.valid)
-			dev_dbg(dev, "RAS registers not found\n");
-
-		dev_dbg(dev, "Set up component registers\n");
-		break;
-	case CXL_REGLOC_RBI_MEMDEV:
-		dev_map = &map->device_map;
-		cxl_probe_device_regs(dev, 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_map->status.valid ? "status " : "",
-				!dev_map->mbox.valid ? "mbox " : "",
-				!dev_map->memdev.valid ? "memdev " : "");
-			return -ENXIO;
-		}
-
-		dev_dbg(dev, "Probing device registers...\n");
-		break;
-	default:
-		break;
-	}
-
-	return 0;
-}
-
-static int cxl_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
+static int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
 			      struct cxl_register_map *map)
 {
 	int rc;
@@ -345,14 +283,7 @@ static int cxl_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
 	if (rc)
 		return rc;
 
-	rc = cxl_map_regblock(map);
-	if (rc)
-		return rc;
-
-	rc = cxl_probe_regs(map);
-	cxl_unmap_regblock(map);
-
-	return rc;
+	return cxl_setup_regs(map);
 }
 
 /*
@@ -683,7 +614,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		dev_warn(&pdev->dev,
 			 "Device DVSEC not present, skip CXL.mem init\n");
 
-	rc = cxl_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map);
+	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map);
 	if (rc)
 		return rc;
 
@@ -696,7 +627,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	 * still be useful for management functions so don't return an error.
 	 */
 	cxlds->component_reg_phys = CXL_RESOURCE_NONE;
-	rc = cxl_setup_regs(pdev, CXL_REGLOC_RBI_COMPONENT, &map);
+	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_COMPONENT, &map);
 	if (rc)
 		dev_warn(&pdev->dev, "No component registers (%d)\n", rc);