Merge tag 'cxl-fixes-6.13-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl

Pull cxl fixes from Ira Weiny:

 - prevent probe failure when non-critical RAS unmasking fails

 - fix CXL 1.1 link status sysfs attribute

 - fix 4 way (and greater) switch interleave region creation

* tag 'cxl-fixes-6.13-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl:
  cxl/region: Fix region creation for greater than x2 switches
  cxl/pci: Check dport->regs.rcd_pcie_cap availability before accessing
  cxl/pci: Fix potential bogus return value upon successful probing

Author: torvalds

drivers/cxl/core/region.c

@@ -1295,6 +1295,7 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 	struct cxl_region_params *p = &cxlr->params;
 	struct cxl_decoder *cxld = cxl_rr->decoder;
 	struct cxl_switch_decoder *cxlsd;
+	struct cxl_port *iter = port;
 	u16 eig, peig;
 	u8 eiw, peiw;
 
@@ -1311,16 +1312,26 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 
 	cxlsd = to_cxl_switch_decoder(&cxld->dev);
 	if (cxl_rr->nr_targets_set) {
-		int i, distance;
+		int i, distance = 1;
+		struct cxl_region_ref *cxl_rr_iter;
 
 		/*
-		 * Passthrough decoders impose no distance requirements between
-		 * peers
+		 * The "distance" between peer downstream ports represents which
+		 * endpoint positions in the region interleave a given port can
+		 * host.
+		 *
+		 * For example, at the root of a hierarchy the distance is
+		 * always 1 as every index targets a different host-bridge. At
+		 * each subsequent switch level those ports map every Nth region
+		 * position where N is the width of the switch == distance.
 		 */
-		if (cxl_rr->nr_targets == 1)
-			distance = 0;
-		else
-			distance = p->nr_targets / cxl_rr->nr_targets;
+		do {
+			cxl_rr_iter = cxl_rr_load(iter, cxlr);
+			distance *= cxl_rr_iter->nr_targets;
+			iter = to_cxl_port(iter->dev.parent);
+		} while (!is_cxl_root(iter));
+		distance *= cxlrd->cxlsd.cxld.interleave_ways;
+
 		for (i = 0; i < cxl_rr->nr_targets_set; i++)
 			if (ep->dport == cxlsd->target[i]) {
 				rc = check_last_peer(cxled, ep, cxl_rr,

drivers/cxl/pci.c

@@ -836,6 +836,9 @@ static ssize_t rcd_pcie_cap_emit(struct device *dev, u16 offset, char *buf, size
 	if (!root_dev)
 		return -ENXIO;
 
+	if (!dport->regs.rcd_pcie_cap)
+		return -ENXIO;
+
 	guard(device)(root_dev);
 	if (!root_dev->driver)
 		return -ENXIO;
@@ -1032,8 +1035,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (rc)
 		return rc;
 
-	rc = cxl_pci_ras_unmask(pdev);
-	if (rc)
+	if (cxl_pci_ras_unmask(pdev))
 		dev_dbg(&pdev->dev, "No RAS reporting unmasked\n");
 
 	pci_save_state(pdev);