commit fe0c826464620fde9124f903d97102bb4237afa7
Author: Haren Myneni <haren@linux.ibm.com>
Date:   Fri Jun 21 15:43:24 2024 -0700

    drmgr/phb: Add multipath partner device support for hotplug add
    
    The PHB node can have "ibm,multipath-partner-drc" property
    which means the device can be also configured with multipath
    partner path. This property provides the DRC index of the
    partner device. So for the hotplug add, both paths should be
    added and the following steps will be executed for the PHB add:
    
    - Add the specified PHB device
    - Find the partner path DRC index from "ibm,multipath-partner-drc"
      property for the specified device
    - If the node has this property and the partner path is
      already added, notify user about the partner device.
    - If the node has this property and the partner path can be
      configured, notify user to configure and add the partner
      device.
    
    Signed-off-by: Haren Myneni <haren@linux.ibm.com>
    Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>

diff --git a/src/drmgr/drslot_chrp_phb.c b/src/drmgr/drslot_chrp_phb.c
index b3a4190..220d844 100644
--- a/src/drmgr/drslot_chrp_phb.c
+++ b/src/drmgr/drslot_chrp_phb.c
@@ -441,8 +441,13 @@ static int acquire_phb(char *drc_name, struct dr_node **phb)
  */
 static int add_phb(void)
 {
-	struct dr_node *phb = NULL;
+	struct dr_node *phb = NULL, *partner_phb = NULL;
+	uint32_t partner_drc_index = 0;
+	char drc_index_str[10];
 	int rc, n_children = 0;
+	struct dr_connector drc;
+	char path[DR_PATH_MAX];
+	int partner_rc = 0;
 
 	phb = get_node_by_name(usr_drc_name, PHB_NODES);
 	if (phb) {
@@ -507,10 +512,40 @@ static int add_phb(void)
 		}
 	}
 
+	if (!rc) {
+		/* Find the multipath partner device index if available */
+		partner_rc = get_my_partner_drc_index(phb, &partner_drc_index);
+		if (!partner_rc && partner_drc_index) {
+			sprintf(drc_index_str, "%d", partner_drc_index);
+			/* If the partner device is already added */
+			partner_phb = get_node_by_name(drc_index_str,
+							PHB_NODES);
+			if (partner_phb) {
+				printf("<%s> has partner device <%s>\n",
+				       phb->drc_name, partner_phb->drc_name);
+			} else {
+				/*
+				 * Find out if the partner device can be
+				 * configured. Get the DRC info for the
+				 * partner DRC index
+				 */
+				partner_rc = get_drc_by_index(partner_drc_index,
+							&drc, path, OFDT_BASE);
+				if (partner_rc)
+					printf("<%s> can have partner "
+						"device but not assigned to "
+						"LPAR yet\n", phb->drc_name);
+			}
+		}
+	}
+
 phb_add_error:
 	if (phb)
 		free_node(phb);
 
+	if (partner_phb)
+		free_node(partner_phb);
+
 	return rc;
 }