Error handling may trigger spurious link events, which may trigger
hotplug handling to re-enumerate the topology. This patch temporarily
disables notification during such error handling and checks the topology
for changes after reset.
Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx>
---
drivers/pci/hotplug/pciehp.h | 1 +
drivers/pci/hotplug/pciehp_core.c | 39 +++++++++++++++++++++++++++++++++++++++
drivers/pci/hotplug/pciehp_hpc.c | 9 +++++++++
3 files changed, 49 insertions(+)
diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index 3a53a24f22f0..f43bcf291c4e 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -194,6 +194,7 @@ void pciehp_get_attention_status(struct slot *slot, u8 *status);
void pciehp_set_attention_status(struct slot *slot, u8 status);
void pciehp_get_latch_status(struct slot *slot, u8 *status);
void pciehp_get_adapter_status(struct slot *slot, u8 *status);
+void pciehp_get_adapter_changed(struct slot *slot, u8 *changed);
int pciehp_query_power_fault(struct slot *slot);
void pciehp_green_led_on(struct slot *slot);
void pciehp_green_led_off(struct slot *slot);
diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index ec48c9433ae5..7181fd991068 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -301,6 +301,43 @@ static void pciehp_remove(struct pcie_device *dev)
pciehp_release_ctrl(ctrl);
}
+static void pciehp_error_detected(struct pcie_device *dev)
+{
+ struct controller *ctrl = get_service_data(dev);
+
+ /*
+ * Shutdown notification to ignore hotplug events during error
+ * handling. We'll recheck the status when error handling completes.
+ *
+ * It is possible link event related to this error handling may have
+ * triggered a the hotplug interrupt ahead of this notification, but we
+ * can't do anything about that race.
+ */
+ pcie_shutdown_notification(ctrl);
+}
+
+static void pciehp_slot_reset(struct pcie_device *dev)
+{
+ struct controller *ctrl = get_service_data(dev);
+ u8 changed;
+
+ /*
+ * Cache presence detect change, but ignore other hotplug events that
+ * may occur during error handling. Ports that implement only in-band
+ * presence detection may inadvertently believe the device has changed,
+ * so those devices will have to be re-enumerated.
+ */
+ pciehp_get_adapter_changed(ctrl->slot, &changed);
+ pcie_clear_hotplug_events(ctrl);
+ pcie_init_notification(ctrl);
+
+ if (changed) {
+ pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);
+ __pci_walk_bus(parent, pci_dev_set_disconnected, NULL);
+ } else if (atomic_read(&ctrl->pending_events) && !pciehp_poll_mode)
+ irq_wake_thread(ctrl->pcie->irq, ctrl);
+}
+
#ifdef CONFIG_PM
static int pciehp_suspend(struct pcie_device *dev)
{
@@ -340,6 +377,8 @@ static struct pcie_port_service_driver hpdriver_portdrv = {
.probe = pciehp_probe,
.remove = pciehp_remove,
+ .error_detected = pciehp_error_detected,
+ .slot_reset = pciehp_slot_reset,
#ifdef CONFIG_PM
.suspend = pciehp_suspend,
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 52a18a7ec2a2..5ec2bc871a9c 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -382,6 +382,15 @@ void pciehp_get_adapter_status(struct slot *slot, u8 *status)
*status = !!(slot_status & PCI_EXP_SLTSTA_PDS);
}
+void pciehp_get_adapter_changed(struct slot *slot, u8 *changed)
+{
+ struct pci_dev *pdev = ctrl_dev(slot->ctrl);
+ u16 slot_status;
+
+ pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
+ *changed = !!(slot_status & PCI_EXP_SLTSTA_PDC);
+}
+
int pciehp_query_power_fault(struct slot *slot)
{
struct pci_dev *pdev = ctrl_dev(slot->ctrl);
--
2.14.4
