[Skiboot] [PATCH v3 4/9] core/pci: Update PCI topology after power change

[Gavin Shan]

When OPAL_SUCCESS is returned from slot->ops.set_power_state(),
we need update the PCI toplogy accordingly. This scenario can
happen when builtin power control functionality is ignored to
accomodate PCI surprise hotplug or not supported at all by the
hardware.

Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>
---
 core/pci-opal.c | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/core/pci-opal.c b/core/pci-opal.c
index ba7a261..27872aa 100644
--- a/core/pci-opal.c
+++ b/core/pci-opal.c
@@ -805,8 +805,8 @@ static int64_t opal_pci_set_power_state(uint64_t async_token,
 			return OPAL_PARAMETER;
 
 		pci_remove_bus(phb, &pd->children);
-		rc = OPAL_SUCCESS;
-		break;
+		phb_unlock(phb);
+		return OPAL_SUCCESS;
 	case OPAL_PCI_SLOT_ONLINE:
 		if (!pd)
 			return OPAL_PARAMETER;
@@ -814,19 +814,35 @@ static int64_t opal_pci_set_power_state(uint64_t async_token,
 			     &pd->children, pd, true);
 		pci_add_device_nodes(phb, &pd->children, pd->dn,
 				     &phb->lstate, 0);
-		rc = OPAL_SUCCESS;
-		break;
+		phb_unlock(phb);
+		return OPAL_SUCCESS;
 	default:
 		rc = OPAL_PARAMETER;
 	}
 
-	phb_unlock(phb);
+	/*
+	 * OPAL_ASYNC_COMPLETION is returned when delay is needed to change
+	 * the power state in the backend. When it can be finished without
+	 * delay, OPAL_SUCCESS is returned. The PCI topology needs to be
+	 * updated in both cases.
+	 */
 	if (rc == OPAL_ASYNC_COMPLETION) {
 		slot->retries = 500;
 		init_timer(&slot->timer, set_power_timer, slot);
 		schedule_timer(&slot->timer, msecs_to_tb(10));
+	} else if (rc == OPAL_SUCCESS) {
+		if (*state == OPAL_PCI_SLOT_POWER_OFF) {
+			pci_remove_bus(phb, &pd->children);
+		} else {
+			slot->ops.prepare_link_change(slot, true);
+			pci_scan_bus(phb, pd->secondary_bus,
+				pd->subordinate_bus, &pd->children, pd, true);
+			pci_add_device_nodes(phb, &pd->children, pd->dn,
+				&phb->lstate, 0);
+		}
 	}
 
+	phb_unlock(phb);
 	return rc;
 }
 opal_call(OPAL_PCI_SET_POWER_STATE, opal_pci_set_power_state, 3);
-- 
2.1.0