cxl/core/port: Make passthrough decoder init implicit

Unused CXL decoders, or ports which use a passthrough decoder (no HDM
decoder registers) are expected to be initialized in a specific way.
Since upcoming drivers will want the same initialization, and it was
already a requirement to have consumers of the API configure the decoder
specific to their needs, initialize to this passthrough state by
default.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/164298418778.3018233.13573986275832546547.stgit@dwillia2-desk3.amr.corp.intel.comSigned-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/cxl/acpi.c

@@ -264,11 +264,6 @@ static int add_host_bridge_uport(struct device *match, void *arg)
 	if (IS_ERR(cxld))
 		return PTR_ERR(cxld);
 
-	cxld->interleave_ways = 1;
-	cxld->interleave_granularity = PAGE_SIZE;
-	cxld->target_type = CXL_DECODER_EXPANDER;
-	cxld->platform_res = (struct resource)DEFINE_RES_MEM(0, 0);
-
 	device_lock(&port->dev);
 	dport = list_first_entry(&port->dports, typeof(*dport), list);
 	device_unlock(&port->dev);

drivers/cxl/core/port.c

@@ -505,7 +505,8 @@ static int decoder_populate_targets(struct cxl_decoder *cxld,
  * some address space for CXL.mem utilization. A decoder is expected to be
  * configured by the caller before registering.
  *
- * Return: A new cxl decoder to be registered by cxl_decoder_add()
+ * Return: A new cxl decoder to be registered by cxl_decoder_add(). The decoder
+ *	   is initialized to be a "passthrough" decoder.
  */
 static struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port,
 					     unsigned int nr_targets)
@@ -537,6 +538,12 @@ static struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port,
 	else
 		cxld->dev.type = &cxl_decoder_switch_type;
 
+	/* Pre initialize an "empty" decoder */
+	cxld->interleave_ways = 1;
+	cxld->interleave_granularity = PAGE_SIZE;
+	cxld->target_type = CXL_DECODER_EXPANDER;
+	cxld->platform_res = (struct resource)DEFINE_RES_MEM(0, 0);
+
 	return cxld;
 err:
 	kfree(cxld);