cxl/core: Drop ->platform_res attribute for root decoders

Root decoders are responsible for hosting the available host address
space for endpoints and regions to claim. The tracking of that available
capacity can be done in iomem_resource directly. As a result, root
decoders no longer need to host their own resource tree. The
current ->platform_res attribute was added prematurely.

Otherwise, ->hpa_range fills the role of conveying the current decode
range of the decoder.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Adam Manzanares <a.manzanares@samsung.com>
Link: https://lore.kernel.org/r/165603873619.551046.791596854070136223.stgit@dwillia2-xfh
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/cxl/acpi.c

@@ -108,8 +108,10 @@ 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->platform_res = (struct resource)DEFINE_RES_MEM(cfmws->base_hpa,
-							     cfmws->window_size);
+	cxld->hpa_range = (struct range) {
+		.start = cfmws->base_hpa,
+		.end = cfmws->base_hpa + cfmws->window_size - 1,
+	};
 	cxld->interleave_ways = CFMWS_INTERLEAVE_WAYS(cfmws);
 	cxld->interleave_granularity = CFMWS_INTERLEAVE_GRANULARITY(cfmws);
 
@@ -119,13 +121,14 @@ 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 %pr\n",
-			&cxld->platform_res);
+		dev_err(dev, "Failed to add decode range [%#llx - %#llx]\n",
+			cxld->hpa_range.start, cxld->hpa_range.end);
 		return 0;
 	}
-	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);
+	dev_dbg(dev, "add: %s node: %d range [%#llx - %#llx]\n",
+		dev_name(&cxld->dev),
+		phys_to_target_node(cxld->hpa_range.start),
+		cxld->hpa_range.start, cxld->hpa_range.end);
 
 	return 0;
 }

drivers/cxl/core/pci.c

@@ -225,7 +225,6 @@ static int dvsec_range_allowed(struct device *dev, void *arg)
 {
 	struct range *dev_range = arg;
 	struct cxl_decoder *cxld;
-	struct range root_range;
 
 	if (!is_root_decoder(dev))
 		return 0;
@@ -237,12 +236,7 @@ static int dvsec_range_allowed(struct device *dev, void *arg)
 	if (!(cxld->flags & CXL_DECODER_F_RAM))
 		return 0;
 
-	root_range = (struct range) {
-		.start = cxld->platform_res.start,
-		.end = cxld->platform_res.end,
-	};
-
-	return range_contains(&root_range, dev_range);
+	return range_contains(&cxld->hpa_range, dev_range);
 }
 
 static void disable_hdm(void *_cxlhdm)

drivers/cxl/core/port.c

@@ -73,14 +73,8 @@ static ssize_t start_show(struct device *dev, struct device_attribute *attr,
 			  char *buf)
 {
 	struct cxl_decoder *cxld = to_cxl_decoder(dev);
-	u64 start;
 
-	if (is_root_decoder(dev))
-		start = cxld->platform_res.start;
-	else
-		start = cxld->hpa_range.start;
-
-	return sysfs_emit(buf, "%#llx\n", start);
+	return sysfs_emit(buf, "%#llx\n", cxld->hpa_range.start);
 }
 static DEVICE_ATTR_ADMIN_RO(start);
 
@@ -88,14 +82,8 @@ 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->hpa_range);
-
-	return sysfs_emit(buf, "%#llx\n", size);
+	return sysfs_emit(buf, "%#llx\n", range_len(&cxld->hpa_range));
 }
 static DEVICE_ATTR_RO(size);
 
@@ -1233,7 +1221,10 @@ static struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port,
 	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);
+	cxld->hpa_range = (struct range) {
+		.start = 0,
+		.end = -1,
+	};
 
 	return cxld;
 err:
@@ -1347,13 +1338,6 @@ int cxl_decoder_add_locked(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_locked, CXL);

drivers/cxl/cxl.h

@@ -197,7 +197,6 @@ enum cxl_decoder_type {
  * struct cxl_decoder - CXL address range decode configuration
  * @dev: this decoder's device
  * @id: kernel device name id
- * @platform_res: address space resources considered by root decoder
  * @hpa_range: Host physical address range mapped by this decoder
  * @interleave_ways: number of cxl_dports in this decode
  * @interleave_granularity: data stride per dport
@@ -210,10 +209,7 @@ enum cxl_decoder_type {
 struct cxl_decoder {
 	struct device dev;
 	int id;
-	union {
-		struct resource platform_res;
-		struct range hpa_range;
-	};
+	struct range hpa_range;
 	int interleave_ways;
 	int interleave_granularity;
 	enum cxl_decoder_type target_type;