cxl/port: Limit the port driver to just the HDM Decoder Capability

Update the port driver to use cxl_map_component_registers() so that the
component register block can be shared between the cxl_pci driver and
the cxl_port driver. I.e. stop the port driver from reserving the entire
component register block for itself via request_region() when it only
needs the HDM Decoder Capability subset.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/166974411625.1608150.7149373371599960307.stgit@djiang5-desk3.ch.intel.comSigned-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/cxl/core/hdm.c

@@ -82,18 +82,22 @@ static void parse_hdm_decoder_caps(struct cxl_hdm *cxlhdm)
 		cxlhdm->interleave_mask |= GENMASK(14, 12);
 }
 
-static void __iomem *map_hdm_decoder_regs(struct cxl_port *port,
-					  void __iomem *crb)
+static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb,
+				struct cxl_component_regs *regs)
 {
-	struct cxl_component_reg_map map;
+	struct cxl_register_map map = {
+		.resource = port->component_reg_phys,
+		.base = crb,
+		.max_size = CXL_COMPONENT_REG_BLOCK_SIZE,
+	};
 
-	cxl_probe_component_regs(&port->dev, crb, &map);
-	if (!map.hdm_decoder.valid) {
+	cxl_probe_component_regs(&port->dev, crb, &map.component_map);
+	if (!map.component_map.hdm_decoder.valid) {
 		dev_err(&port->dev, "HDM decoder registers invalid\n");
-		return IOMEM_ERR_PTR(-ENXIO);
+		return -ENXIO;
 	}
 
-	return crb + map.hdm_decoder.offset;
+	return cxl_map_component_regs(&port->dev, regs, &map);
 }
 
 /**
@@ -103,25 +107,25 @@ static void __iomem *map_hdm_decoder_regs(struct cxl_port *port,
 struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port)
 {
 	struct device *dev = &port->dev;
-	void __iomem *crb, *hdm;
 	struct cxl_hdm *cxlhdm;
+	void __iomem *crb;
+	int rc;
 
 	cxlhdm = devm_kzalloc(dev, sizeof(*cxlhdm), GFP_KERNEL);
 	if (!cxlhdm)
 		return ERR_PTR(-ENOMEM);
 
 	cxlhdm->port = port;
-	crb = devm_cxl_iomap_block(dev, port->component_reg_phys,
-				   CXL_COMPONENT_REG_BLOCK_SIZE);
+	crb = ioremap(port->component_reg_phys, CXL_COMPONENT_REG_BLOCK_SIZE);
 	if (!crb) {
 		dev_err(dev, "No component registers mapped\n");
 		return ERR_PTR(-ENXIO);
 	}
 
-	hdm = map_hdm_decoder_regs(port, crb);
-	if (IS_ERR(hdm))
-		return ERR_CAST(hdm);
-	cxlhdm->regs.hdm_decoder = hdm;
+	rc = map_hdm_decoder_regs(port, crb, &cxlhdm->regs);
+	iounmap(crb);
+	if (rc)
+		return ERR_PTR(rc);
 
 	parse_hdm_decoder_caps(cxlhdm);
 	if (cxlhdm->decoder_count == 0) {