/*
* On PowerNV platform, we might already have fenced PHB there.
* For that case, it's meaningless to recover frozen PE. Intead,
* We have to handle fenced PHB firstly.
*/
static int eeh_phb_check_failure(struct eeh_pe *pe)
{
struct eeh_pe *phb_pe;
unsigned long flags;
int ret;
if (!eeh_has_flag(EEH_PROBE_MODE_DEV))
return -EPERM;
/* Find the PHB PE */
phb_pe = eeh_phb_pe_get(pe->phb);
if (!phb_pe) {
pr_warn("%s Can't find PE for PHB#%d\n",
__func__, pe->phb->global_number);
return -EEXIST;
}
/* If the PHB has been in problematic state */
eeh_serialize_lock(&flags);
if (phb_pe->state & EEH_PE_ISOLATED) {
ret = 0;
goto out;
}
/* Check PHB state */
ret = eeh_ops->get_state(phb_pe, NULL);
if ((ret < 0) ||
(ret == EEH_STATE_NOT_SUPPORT) ||
(ret & (EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE)) ==
(EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE)) {
ret = 0;
goto out;
}
/* Isolate the PHB and send event */
eeh_pe_state_mark(phb_pe, EEH_PE_ISOLATED);
eeh_serialize_unlock(flags);
pr_err("EEH: PHB#%x failure detected, location: %s\n",
phb_pe->phb->global_number, eeh_pe_loc_get(phb_pe));
dump_stack();
eeh_send_failure_event(phb_pe);
return 1;
out:
eeh_serialize_unlock(flags);
return ret;
}
/**
* eeh_event_handler - Dispatch EEH events.
* @dummy - unused
*
* The detection of a frozen slot can occur inside an interrupt,
* where it can be hard to do anything about it. The goal of this
* routine is to pull these detection events out of the context
* of the interrupt handler, and re-dispatch them for processing
* at a later time in a normal context.
*/
static int eeh_event_handler(void * dummy)
{
unsigned long flags;
struct eeh_event *event;
struct eeh_pe *pe;
while (!kthread_should_stop()) {
if (down_interruptible(&eeh_eventlist_sem))
break;
/* Fetch EEH event from the queue */
spin_lock_irqsave(&eeh_eventlist_lock, flags);
event = NULL;
if (!list_empty(&eeh_eventlist)) {
event = list_entry(eeh_eventlist.next,
struct eeh_event, list);
list_del(&event->list);
}
spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
if (!event)
continue;
/* We might have event without binding PE */
pe = event->pe;
if (pe) {
eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
if (pe->type & EEH_PE_PHB)
pr_info("EEH: Detected error on PHB#%d\n",
pe->phb->global_number);
else
pr_info("EEH: Detected PCI bus error on "
"PHB#%d-PE#%x\n",
pe->phb->global_number, pe->addr);
eeh_handle_event(pe);
eeh_pe_state_clear(pe, EEH_PE_RECOVERING);
} else {
eeh_handle_event(NULL);
}
kfree(event);
}
/**
* eeh_reset_device - Perform actual reset of a pci slot
* @pe: EEH PE
* @bus: PCI bus corresponding to the isolcated slot
*
* This routine must be called to do reset on the indicated PE.
* During the reset, udev might be invoked because those affected
* PCI devices will be removed and then added.
*/
static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus)
{
struct pci_bus *frozen_bus = eeh_pe_bus_get(pe);
struct timeval tstamp;
int cnt, rc, removed = 0;
/* pcibios will clear the counter; save the value */
cnt = pe->freeze_count;
tstamp = pe->tstamp;
/*
* We don't remove the corresponding PE instances because
* we need the information afterwords. The attached EEH
* devices are expected to be attached soon when calling
* into pcibios_add_pci_devices().
*/
eeh_pe_state_mark(pe, EEH_PE_KEEP);
if (bus) {
pci_lock_rescan_remove();
pcibios_remove_pci_devices(bus);
pci_unlock_rescan_remove();
} else if (frozen_bus) {
eeh_pe_dev_traverse(pe, eeh_rmv_device, &removed);
}
/*
* Reset the pci controller. (Asserts RST#; resets config space).
* Reconfigure bridges and devices. Don't try to bring the system
* up if the reset failed for some reason.
*
* During the reset, it's very dangerous to have uncontrolled PCI
* config accesses. So we prefer to block them. However, controlled
* PCI config accesses initiated from EEH itself are allowed.
*/
eeh_pe_state_mark(pe, EEH_PE_RESET);
rc = eeh_reset_pe(pe);
if (rc) {
eeh_pe_state_clear(pe, EEH_PE_RESET);
return rc;
}
pci_lock_rescan_remove();
/* Restore PE */
eeh_ops->configure_bridge(pe);
eeh_pe_restore_bars(pe);
eeh_pe_state_clear(pe, EEH_PE_RESET);
/* Clear frozen state */
rc = eeh_clear_pe_frozen_state(pe);
if (rc)
return rc;
/* Give the system 5 seconds to finish running the user-space
* hotplug shutdown scripts, e.g. ifdown for ethernet. Yes,
* this is a hack, but if we don't do this, and try to bring
* the device up before the scripts have taken it down,
* potentially weird things happen.
*/
if (bus) {
pr_info("EEH: Sleep 5s ahead of complete hotplug\n");
ssleep(5);
/*
* The EEH device is still connected with its parent
* PE. We should disconnect it so the binding can be
* rebuilt when adding PCI devices.
*/
eeh_pe_traverse(pe, eeh_pe_detach_dev, NULL);
pcibios_add_pci_devices(bus);
} else if (frozen_bus && removed) {
pr_info("EEH: Sleep 5s ahead of partial hotplug\n");
ssleep(5);
eeh_pe_traverse(pe, eeh_pe_detach_dev, NULL);
pcibios_add_pci_devices(frozen_bus);
}
eeh_pe_state_clear(pe, EEH_PE_KEEP);
pe->tstamp = tstamp;
pe->freeze_count = cnt;
pci_unlock_rescan_remove();
return 0;
}