cxl/core: Convert decoder range to resource

CXL decoders manage address ranges in a hierarchical fashion whereby a
leaf is a unique subregion of its parent decoder (midlevel or root). It
therefore makes sense to use the resource API for handling this.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> (v1)
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Link: https://lore.kernel.org/r/164298417191.3018233.5201055578165414714.stgit@dwillia2-desk3.amr.corp.intel.comSigned-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/cxl/acpi.c

@@ -108,10 +108,8 @@ static int cxl_parse_cfmws(union acpi_subtable_headers *header, void *arg,
 
 	cxld->flags = cfmws_to_decoder_flags(cfmws->restrictions);
 	cxld->target_type = CXL_DECODER_EXPANDER;
-	cxld->range = (struct range){
-		.start = cfmws->base_hpa,
-		.end = cfmws->base_hpa + cfmws->window_size - 1,
-	};
+	cxld->platform_res = (struct resource)DEFINE_RES_MEM(cfmws->base_hpa,
+							     cfmws->window_size);
 	cxld->interleave_ways = CFMWS_INTERLEAVE_WAYS(cfmws);
 	cxld->interleave_granularity = CFMWS_INTERLEAVE_GRANULARITY(cfmws);
 
@@ -121,14 +119,13 @@ static int cxl_parse_cfmws(union acpi_subtable_headers *header, void *arg,
 	else
 		rc = cxl_decoder_autoremove(dev, cxld);
 	if (rc) {
-		dev_err(dev, "Failed to add decoder for %#llx-%#llx\n",
-			cfmws->base_hpa,
-			cfmws->base_hpa + cfmws->window_size - 1);
+		dev_err(dev, "Failed to add decoder for %pr\n",
+			&cxld->platform_res);
 		return 0;
 	}
-	dev_dbg(dev, "add: %s node: %d range %#llx-%#llx\n",
-		dev_name(&cxld->dev), phys_to_target_node(cxld->range.start),
-		cfmws->base_hpa, cfmws->base_hpa + cfmws->window_size - 1);
+	dev_dbg(dev, "add: %s node: %d range %pr\n", dev_name(&cxld->dev),
+		phys_to_target_node(cxld->platform_res.start),
+		&cxld->platform_res);
 
 	return 0;
 }
@@ -270,10 +267,7 @@ static int add_host_bridge_uport(struct device *match, void *arg)
 	cxld->interleave_ways = 1;
 	cxld->interleave_granularity = PAGE_SIZE;
 	cxld->target_type = CXL_DECODER_EXPANDER;
-	cxld->range = (struct range) {
-		.start = 0,
-		.end = -1,
-	};
+	cxld->platform_res = (struct resource)DEFINE_RES_MEM(0, 0);
 
 	device_lock(&port->dev);
 	dport = list_first_entry(&port->dports, typeof(*dport), list);

drivers/cxl/core/port.c

@@ -46,8 +46,14 @@ static ssize_t start_show(struct device *dev, struct device_attribute *attr,
 			  char *buf)
 {
 	struct cxl_decoder *cxld = to_cxl_decoder(dev);
+	u64 start;
 
-	return sysfs_emit(buf, "%#llx\n", cxld->range.start);
+	if (is_root_decoder(dev))
+		start = cxld->platform_res.start;
+	else
+		start = cxld->decoder_range.start;
+
+	return sysfs_emit(buf, "%#llx\n", start);
 }
 static DEVICE_ATTR_ADMIN_RO(start);
 
@@ -55,8 +61,14 @@ static ssize_t size_show(struct device *dev, struct device_attribute *attr,
 			char *buf)
 {
 	struct cxl_decoder *cxld = to_cxl_decoder(dev);
+	u64 size;
+
+	if (is_root_decoder(dev))
+		size = resource_size(&cxld->platform_res);
+	else
+		size = range_len(&cxld->decoder_range);
 
-	return sysfs_emit(buf, "%#llx\n", range_len(&cxld->range));
+	return sysfs_emit(buf, "%#llx\n", size);
 }
 static DEVICE_ATTR_RO(size);
 
@@ -546,6 +558,13 @@ int cxl_decoder_add(struct cxl_decoder *cxld, int *target_map)
 	if (rc)
 		return rc;
 
+	/*
+	 * Platform decoder resources should show up with a reasonable name. All
+	 * other resources are just sub ranges within the main decoder resource.
+	 */
+	if (is_root_decoder(dev))
+		cxld->platform_res.name = dev_name(dev);
+
 	return device_add(dev);
 }
 EXPORT_SYMBOL_NS_GPL(cxl_decoder_add, CXL);

drivers/cxl/cxl.h

@@ -179,7 +179,8 @@ enum cxl_decoder_type {
  * struct cxl_decoder - CXL address range decode configuration
  * @dev: this decoder's device
  * @id: kernel device name id
- * @range: address range considered by this decoder
+ * @platform_res: address space resources considered by root decoder
+ * @decoder_range: address space resources considered by midlevel decoder
  * @interleave_ways: number of cxl_dports in this decode
  * @interleave_granularity: data stride per dport
  * @target_type: accelerator vs expander (type2 vs type3) selector
@@ -190,7 +191,10 @@ enum cxl_decoder_type {
 struct cxl_decoder {
 	struct device dev;
 	int id;
-	struct range range;
+	union {
+		struct resource platform_res;
+		struct range decoder_range;
+	};
 	int interleave_ways;
 	int interleave_granularity;
 	enum cxl_decoder_type target_type;