cxl/hdm: Use stored Component Register mappings to map HDM decoder capability

Now, that the Component Register mappings are stored, use them to
enable and map the HDM decoder capabilities. The Component Registers
do not need to be probed again for this, remove probing code.

The HDM capability applies to Endpoints, USPs and VH Host Bridges. The
Endpoint's component register mappings are located in the cxlds and
else in the port's structure. Duplicate the cxlds->reg_map in
port->reg_map for endpoint ports.

Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Signed-off-by: Robert Richter <rrichter@amd.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
[rework to drop cxl_port_get_comp_map()]
Link: https://lore.kernel.org/r/20231018171713.1883517-8-rrichter@amd.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Author: Robert Richter

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 = {
-		.host = &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) {

drivers/cxl/core/port.c

@@ -751,16 +751,31 @@ static struct cxl_port *__devm_cxl_add_port(struct device *host,
 		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;
 

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);